Display apparatus with non-overlap image region

Abstract

A display apparatus of the present disclosure includes: a left eyepiece display unit including a left-eye image display device and a left eyepiece optical system guiding a displayed left-eye display image to a left eye; and a right eyepiece display unit including a right-eye image display device and a right eyepiece optical system guiding a displayed right-eye display image to a right eye, and an image magnification upon observation by both eyes is twice or more. The left eyepiece optical system and the right eyepiece optical system each include a plurality of single lenses, and at least one of the single lenses is a free-form surface lens including a resin material. At least one of the single lenses is arranged in at least one of an eccentric state or a rotated state with respect to an optical axis of the left-eye image display device or the right-eye image display device.

Claims

1. A display apparatus comprising: a left eyepiece display unit including a left-eye image display device and a left eyepiece optical system that guides a left-eye display image displayed on the left-eye image display device to a left eye; and a right eyepiece display unit including a right-eye image display device and a right eyepiece optical system that guides a right-eye display image displayed on the right-eye image display device to a right eye, an image magnification upon observation by both eyes being twice or more, the left eyepiece optical system and the right eyepiece optical system each including a plurality of single lenses, at least one of the plurality of single lenses comprising a free-form surface lens including a resin material, at least one of the plurality of single lenses being arranged in at least one of an eccentric state or a rotated state with respect to an optical axis of the left-eye image display device or the right-eye image display device, and the left-eye display image and the right-eye display image each including an overlap image region and a non-overlap image region, the overlap image region including a mutually common image part, the non-overlap image region including a mutually different image part and being a region outside the overlap image region, wherein the left eyepiece optical system and the right eyepiece optical system each include an eyepiece of a three-group three-lens configuration in which a first lens, a second lens, and a third lens are arranged as the plurality of single lenses in order from side of an eye point toward image side, and at least one of the first lens, the second lens, or the third lens is arranged in at least one of the eccentric state or the rotated state with respect to a reference optical axis which employs the eye point as a reference, and the following expressions:
si,max<25 (mm)  (1)
θi,max<25(°)  (2) are satisfied, where si,max denotes a maximum absolute value of an eccentric amount of each of respective optical axes of the first lens, the second lens, and the third lens with respect to the reference optical axis in a direction orthogonal to the reference optical axis, and θi,max denotes a maximum absolute value of a rotational amount of each of the respective optical axes of the first lens, the second lens, and the third lens with respect to the reference optical axis.

2. The display apparatus according to claim 1, wherein the first lens comprises a spherical lens having a positive refractive power including a material of a refractive index of 1.439 or more with respect to a d-line, and a lens surface of the first lens on the side of the eye point has a convex shape or a planar shape.

3. The display apparatus according to claim 1, wherein an optical axis of the first lens is parallel to the reference optical axis which employs the eye point as the reference.

4. The display apparatus according to claim 1, wherein at least one of the second lens or the third lens comprises a free-form surface lens.

5. The display apparatus according to claim 1, wherein an optical axis of the first lens is non-parallel to a reference optical axis which employs the eye point as a reference.

6. The display apparatus according to claim 1, wherein the first lens comprises a Fresnel lens.

7. The display apparatus according to claim 1, wherein the left eyepiece optical system and the right eyepiece optical system each include an eyepiece of a four-group four-lens configuration in which a first lens, a second lens, a third lens, and a fourth lens are arranged as the plurality of single lenses in order from side of an eye point toward image side.

8. The display apparatus according to claim 7, wherein the first lens comprises a spherical lens having a positive refractive power including a material of a refractive index of 1.439 or more with respect to a d-line, and a lens surface of the first lens on the side of the eye point has a convex shape or a planar shape.

9. The display apparatus according to claim 7, wherein an optical axis of the first lens is parallel to a reference optical axis which employs the eye point as a reference.

10. The display apparatus according to claim 7, wherein at least one of the second lens, the third lens, or the fourth lens comprises a free-form surface lens.

11. The display apparatus according to claim 7, wherein at least one of the first lens, the second lens, the third lens, or the fourth lens is arranged in at least one of the eccentric state or the rotated state with respect to a reference optical axis which employs the eye point as a reference, and the following expressions:
si,max<25 (mm)  (1)
θi,max<25(°)  (2) are satisfied, where si,max denotes a maximum absolute value of an eccentric amount of each of respective optical axes of the first lens, the second lens, and the third lens with respect to the reference optical axis in a direction orthogonal to the reference optical axis, and θi,max denotes a maximum absolute value of a rotational amount of each of the respective optical axes of the first lens, the second lens, and the third lens with respect to the reference optical axis.

12. The display apparatus according to claim 7, wherein an optical axis of the first lens is non-parallel to a reference optical axis which employs the eye point as a reference.

13. The display apparatus according to claim 7, wherein the first lens comprises a Fresnel lens.

14. The display apparatus according to claim 1, wherein, in each of the left eyepiece optical system and the right eyepiece optical system, the plurality of single lenses includes a varifocal lens group.

15. The display apparatus according to claim 14, wherein, in each of the left eyepiece optical system and the right eyepiece optical system, the plurality of single lenses includes an eccentric lens group and the varifocal lens group in order from side of an eye point toward image side.

16. The display apparatus according to claim 1, wherein the non-overlap image region is a region on an outer left side of the overlap image region in the left-eye display image, and the non-overlap image region is a region on an outer right side of the overlap image region in the right-eye display image.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an explanatory diagram illustrating a first configuration example of an eyepiece display unit used in a head-mounted display, for example.

(2) FIG. 2 is an explanatory diagram illustrating a second configuration example of the eyepiece display unit used in the head-mounted display, for example.

(3) FIG. 3 is an explanatory diagram of image magnification.

(4) FIG. 4 is a plan view of an overview of a display apparatus according to an embodiment of the present disclosure.

(5) FIG. 5 is a side view of an overview of the display apparatus according to an embodiment.

(6) FIG. 6 is an explanatory diagram illustrating an overview of an appearance of an image by a display apparatus according to a comparative example.

(7) FIG. 7 is an explanatory diagram illustrating an overview of an appearance of an image according to the display apparatus according to an embodiment.

(8) FIG. 8 is an explanatory diagram illustrating an overview of a left-eye display image and a right-eye display image by the display apparatus according to an embodiment.

(9) FIG. 9 is an explanatory diagram schematically illustrating an observation virtual image to be observed by a single eye in the display apparatus according to an embodiment.

(10) FIG. 10 is an explanatory diagram schematically illustrating an observation virtual image to be observed by both eyes in the display apparatus according to an embodiment.

(11) FIG. 11 is an explanatory diagram schematically illustrating a relationship between magnitude of a field angle of view (FOV) as well as magnitude of an eye relief (E.R.) and a height of a light beam passing an outermost of a first surface of an eyepiece.

(12) FIG. 12 is an explanatory diagram of an optical axis of an eyepiece according to each of embodiments.

(13) FIG. 13 is a cross-sectional view of lenses of an eyepiece according to Example 1.

(14) FIG. 14 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 1.

(15) FIG. 15 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 1.

(16) FIG. 16 is a cross-sectional view of lenses of an eyepiece according to Example 2.

(17) FIG. 17 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 2.

(18) FIG. 18 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 2.

(19) FIG. 19 is a cross-sectional view of lenses of an eyepiece according to Example 3.

(20) FIG. 20 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 3.

(21) FIG. 21 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 3.

(22) FIG. 22 is a cross-sectional view of lenses of an eyepiece according to Example 4.

(23) FIG. 23 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 4.

(24) FIG. 24 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 4.

(25) FIG. 25 is a cross-sectional view of lenses of an eyepiece according to Example 5.

(26) FIG. 26 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 5.

(27) FIG. 27 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 5.

(28) FIG. 28 is a cross-sectional view of lenses of an eyepiece according to Example 6.

(29) FIG. 29 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 6.

(30) FIG. 30 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 6.

(31) FIG. 31 is a cross-sectional view of lenses of an eyepiece according to Example 7.

(32) FIG. 32 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 7.

(33) FIG. 33 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 7.

(34) FIG. 34 is a cross-sectional view of lenses of an eyepiece according to Example 8.

(35) FIG. 35 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 8.

(36) FIG. 36 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 8.

(37) FIG. 37 is a cross-sectional view of lenses of an eyepiece according to Example 9.

(38) FIG. 38 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 9.

(39) FIG. 39 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 9.

(40) FIG. 40 is a cross-sectional view of lenses of an eyepiece according to Example 10.

(41) FIG. 41 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 10.

(42) FIG. 42 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 10.

(43) FIG. 43 is a cross-sectional view of lenses of an eyepiece according to Example 11.

(44) FIG. 44 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 11.

(45) FIG. 45 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 11.

(46) FIG. 46 is a cross-sectional view of lenses of an eyepiece according to Example 12.

(47) FIG. 47 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 12.

(48) FIG. 48 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 12.

(49) FIG. 49 is a cross-sectional view of lenses of an eyepiece according to Example 13.

(50) FIG. 50 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 13.

(51) FIG. 51 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 13.

(52) FIG. 52 is a cross-sectional view of lenses of an eyepiece according to Example 14.

(53) FIG. 53 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 14.

(54) FIG. 54 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 14.

(55) FIG. 55 is a cross-sectional view of lenses of an eyepiece according to Example 15.

(56) FIG. 56 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 15.

(57) FIG. 57 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 15.

(58) FIG. 58 is a cross-sectional view of lenses of an eyepiece according to Example 16.

(59) FIG. 59 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 16.

(60) FIG. 60 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 16.

(61) FIG. 61 is a cross-sectional view of lenses of an eyepiece according to Example 17.

(62) FIG. 62 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 17.

(63) FIG. 63 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 17.

(64) FIG. 64 is a cross-sectional view of lenses of an eyepiece according to Example 18.

(65) FIG. 65 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 18.

(66) FIG. 66 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 18.

(67) FIG. 67 is a cross-sectional view of lenses of an eyepiece according to Example 19.

(68) FIG. 68 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 19.

(69) FIG. 69 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 19.

(70) FIG. 70 is a cross-sectional view of lenses of an eyepiece according to Example 20.

(71) FIG. 71 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 20.

(72) FIG. 72 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 20.

(73) FIG. 73 is a cross-sectional view of lenses of an eyepiece according to Example 21.

(74) FIG. 74 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 21.

(75) FIG. 75 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 21.

(76) FIG. 76 is a cross-sectional view of lenses of an eyepiece according to Example 22.

(77) FIG. 77 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 22.

(78) FIG. 78 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 22.

(79) FIG. 79 is a cross-sectional view of lenses of an eyepiece according to Example 23.

(80) FIG. 80 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 23.

(81) FIG. 81 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 23.

(82) FIG. 82 is a cross-sectional view of lenses of an eyepiece according to Example 24.

(83) FIG. 83 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 24.

(84) FIG. 84 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 24.

(85) FIG. 85 is a lens cross-sectional view of an overview of a third configuration example of an eyepiece according to an embodiment.

(86) FIG. 86 is a cross-sectional view of lenses of an eyepiece according to Example 25 at a visual acuity of 1.0.

(87) FIG. 87 is a cross-sectional view of lenses of the eyepiece according to Example 25 at a visual acuity of 0.2.

(88) FIG. 88 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 25 at a visual acuity of 1.0.

(89) FIG. 89 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 25 at a visual acuity of 1.0.

(90) FIG. 90 is an aberration diagram illustrating field curvature and distortion of the eyepiece according to Example 25 at a visual acuity of 0.2.

(91) FIG. 91 is an aberration diagram illustrating chromatic aberration of magnification of the eyepiece according to Example 25 at a visual acuity of 0.2.

(92) FIG. 92 is an external perspective view of a head-mounted display as an example of a display apparatus as viewed obliquely from the front.

(93) FIG. 93 is an external perspective view of the head-mounted display as an example of the display apparatus as viewed obliquely from the rear.

MODES FOR CARRYING OUT THE INVENTION

(94) Hereinafter, description is given in detail of embodiments of the present disclosure with reference to the drawings. It is to be noted that the description is given in the following order.

(95) 0. Comparative Example

(96) 1. Overview of Display Apparatus according to Embodiment

(97) 2. Configuration Example and Workings and Effects of Eyepiece Optical System (Eyepiece)

(98) 3. Example of Application to Head-Mounted Display

(99) 4. Numerical Examples of Eyepiece Optical System (Eyepiece)

(100) 5. Other Embodiments

0. Comparative Example

(101) FIG. 1 illustrates a first configuration example of an eyepiece display unit 102 used in a head-mounted display, for example. FIG. 2 illustrates a second configuration example of the eyepiece display unit 102 used in the head-mounted display, for example.

(102) The eyepiece display unit 102 includes an eyepiece optical system 101 and an image display device 100 in order from side of an eye point E.P. along an optical axis Z1.

(103) The image display device 100 is, for example, a display panel such as an LCD (Liquid Crystal Display) or an organic EL display. The eyepiece optical system 101 is used to magnify and display an image displayed on the image display device 100. The eyepiece optical system 101 is configured by, for example, an eyepiece including a plurality of lenses. With use of the eyepiece optical system 101, an observer observes a virtual image Im that is displayed in a magnified manner. A sealing glass, etc. adapted to protect the image display device 100 may be disposed on a front surface of the image display device 100. The eye point E.P. corresponds to a position of a pupil of the observer and also serves as an aperture stop STO.

(104) Here, FIG. 1 illustrates a configuration example in a case where a size of the image display device 100 is smaller than a diameter of the eyepiece optical system 101. FIG. 2 illustrates a configuration example in a case where the size of the image display device 100 is large than the diameter of the eyepiece optical system 101.

(105) In a head-mounted display having a high viewing angle with a field angle of view over 70° and using the coaxial eyepiece optical system 101, the image display device 100 is often larger than the diameter of the eyepiece optical system 101. In such a head-mounted display, an image magnification My is suppressed to be small, but a focal length f becomes relatively long. This leads to a concern that the eyepiece optical system 101 has along total length. In addition, the size of the eyepiece optical system 101 is sometimes limited not by the size of the eyepiece optical system 101 but by the size of the image display device 100. This further leads to an issue of unsuitableness for reduction in size.

(106) For example, as illustrated in FIG. 1, in a case where the size of the image display device 100 is small, the size of the entire eyepiece display unit 102 is limited by the size of the eyepiece optical system 101. In contrast, as illustrated in FIG. 2, in a case where the size of the image display device 100 is large, the size of the entire eyepiece display unit 102 is limited by the size of the image display device 100.

(107) It is to be noted that the image magnification My is expressed by Mv=α′/α. As illustrated in the upper part of FIG. 3, a denotes a field angle of view in a case where the eyepiece optical system 101 is not provided. In addition, as illustrated in a lower part of FIG. 3, α′ denotes a field angle of view (field angle of view with respect to the virtual image Im) in a case where the eyepiece optical system 101 is provided. In FIG. 3, h is a maximum image height of an image to be observed, and is, for example, a maximum image height of an image displayed on the image display device 100. For example, in a case where the image display device 100 has a rectangular shape, h is a half value of a diagonal size of the image display device 100. f denotes a focal length of the eyepiece optical system 101.

(108) In addition, the image magnification My is expressed by the following expression (A):
Mv=ω′/(tan.sup.−1(h/L))  (A) where ω′ is a half value (rad) of a maximum field angle of view, h is a maximum image height, and L is a total length (a distance from the eye point E.P. to an image).

(109) It is to be noted that the image refers to an image displayed on the image display device 100, for example. For example, in the case where the image display device 100 has the rectangular shape, h is the half value of the diagonal size of the image display device 100, as described above. L corresponds to the total length of the eyepiece optical system 101 described above (a distance from the eye point E.P. to a display surface of the image display device 100), for example.

(110) In the head-mounted display having a high viewing angle with a field angle of view over 70°, using the image display device 100 having a small size relative to the diameter of the eyepiece optical system 101 as illustrated in the configuration example in FIG. 1 enables reduction in the total length and size of the eyepiece optical system 101 as compared with the case of using the image display device 100 having a large size. This is believed to contribute advantageously to reduction in size of the head-mounted display. However, in a case of attempting to achieve such a head-mounted display without using a reflective device, there is an issue of difficulty in increasing the image magnification My when attempting to increase an image-forming capability.

(111) To address the above-described issue, PTL 1 (Japanese Unexamined Patent Application Publication No. H7-244246) has attempted to solve the issue by an eyepiece optical system using a Fresnel lens. In the eyepiece optical system described in PTL 1, use of a meniscus-shaped Fresnel lens achieves both a high imaging-forming capability and a high image magnification Mv. However, the Fresnel lens generates stray light depending on the shape of a Fresnel lens surface, thus causing a concern about generation of a sense of discomfort when observing an image through the eyepiece optical system.

(112) It is therefore desired to develop a display apparatus suitable for the head-mounted display, etc. that makes it possible to achieve a lighter weight and a wider angle of view upon observation by both eyes without causing a concern about generation of stray light and to provide high-definition beauty of an image.

1. Overview of Display Apparatus According to Embodiment

(113) A display apparatus according to an embodiment of the present disclosure is applicable to the head-mounted display, for example.

(114) FIGS. 4 and 5 each illustrate an overview of a display apparatus 1 according to an embodiment of the present disclosure. FIG. 4 illustrates a configuration of the display apparatus 1 in an x-z plane. FIG. 5 illustrates a configuration of the display apparatus 1 as viewed from a side surface (y-z plane). FIG. 6 illustrates an overview of an appearance of an image by a display apparatus according to a comparative example. FIG. 7 illustrates an overview of an appearance of an image by the display apparatus 1. FIG. 8 illustrates an overview of a left-eye display image 10L and a right-eye display image 10R by the display apparatus 1.

(115) As illustrated in FIGS. 4 and 5, the display apparatus 1 includes a left eyepiece display unit 102L and a right eyepiece display unit 102R arranged side by side at positions corresponding to locations of both eyes. The display apparatus 1 is configured to allow the image magnification My to be twice or more upon observation by both eyes.

(116) The left eyepiece display unit 102L includes a left-eye image display device 100L and a left eyepiece optical system 101L that guides the left-eye display image 10L displayed on the left-eye image display device 100L to a left eye 2L.

(117) The right eyepiece display unit 102R includes a right-eye image display device 100R and a right eyepiece optical system 101R that guides the right-eye display image 10R displayed on the right-eye image display device 100R to a right eye 2R.

(118) Each of the left eyepiece optical system 101L and the right eyepiece optical system 101R is configured by an eyepiece including a plurality of single lenses.

(119) In the left eyepiece optical system 101L and the right eyepiece optical system 101R, at least one of the plurality of single lenses is a free-form surface lens including a resin material. Employing a resin material for at least one of the plurality of single lenses makes it possible to reduce weights of the left eyepiece optical system 101L and the right eyepiece optical system 101R. In addition, employing the free-form surface lens for at least one of the plurality of single lenses makes it possible to suppress generation of aberration.

(120) In the left eyepiece optical system 101L and the right eyepiece optical system 101R, at least one of the plurality of single lenses is arranged in at least one of an eccentric state or a rotated state with respect to an optical axis of the left-eye image display device 100L or the right-eye image display device 100R. Arranging the lens in such a state makes it possible to suppress aberration and to achieve a light-weighted optical system with a wide angle of view.

(121) Each of the left-eye image display device 100L and the right-eye image display device 100R is configured by, for example, a flat-type small display panel such as an LCD and an organic EL display.

(122) Here, as illustrated in the comparative example in FIG. 6, in the normal display apparatus such as a head-mounted display, the identical image is displayed in the left-eye image display device 100L and the right-eye image display device 100R, and the identical image is observed in the left eye 2L and the right eye 2R, as illustrated in the upper part of FIG. 6. As a result, as illustrated in the lower part of FIG. 6, when viewed by both eyes, an image is observed at the identical angle of view as the field angle of view in a single eye.

(123) In contrast, in the display apparatus 1 according to the present disclosure, as illustrated in FIG. 7, images partially different from each other are displayed in the left-eye image display device 100L and the right-eye image display device 100R, and images partially different from each other are observed in the left eye 2L and the right eye 2R, as illustrated in the upper part of FIG. 7. As a result, as illustrated in the lower part of FIG. 7, when viewed by both eyes, an image is observed in a wider angle of view than the field angle of view by a single eye.

(124) As illustrated in FIG. 8, each of the left-eye display image 10L and the right-eye display image 10R includes an overlap image region 11 and a non-overlap image region 12. The overlap image region 11 is an image region including an image part mutually common to the left-eye display image 10L and the right-eye display image 10R.

(125) The non-overlap image region 12 is an image region including an image part mutually different between the left-eye display image 10L and the right-eye display image 10R; the non-overlap image region 12 is a region outside the overlap image region 11 in each of the left-eye display image 10L and the right-eye display image 10R. For example, as illustrated in FIG. 8, in the left-eye display image 10L, the non-overlap image region 12 constitutes a region on outer left side of the overlap image region 11. In addition, in the right-eye display image 10R, the non-overlap image region 12 constitutes a region on outer right side of the overlap image region 11. It is to be noted that a front gaze point C0L of the observer in the left-eye display image 10L and a front gaze point C0R of the observer in the right-eye display image 10R are within the overlap image region 11.

(126) As described above, providing the overlap image region 11 and the non-overlap image region 12 in the left-eye display image 10L and the right-eye display image 10R allows for prospects of a wider angle of view upon observation by both eyes as compared with the case where the left-eye display image 10L and the right-eye display image 10R are configured only by an overlapped region.

(127) (Concerning Field Angle of View (FOV))

(128) FIG. 9 schematically illustrates an observations virtual image (a left-eye observation virtual image ImL or a right-eye observation virtual image ImR) to be observed by a single eye in the display apparatus 1. FIG. 10 schematically illustrates an observations virtual image (a both-eye observation virtual image ImLR) to be observed by both eyes in the display apparatus 1.

(129) As illustrated in FIG. 9, upon observation by a single eye, the maximum angle of view of one side (left side or right side) with reference to the front gaze point (C0L, C0R) is defined as θa, and the maximum angle of view of the other side (right side or left side) is defined as θb (θa>θb). θb corresponds to the maximum angle of view of the overlap image region 11. As for the maximum angle of view upon observation by both eyes, the maximum angle of view is θa on both the left side and the right side with reference to the front gaze point C0, and thus the maximum angle of view is wider than that upon observation by a single eye.

2. Configuration Example and Workings and Effects of Eyepiece Optical System (Eyepiece)

(130) Next, description is given of first to third configuration examples of the eyepiece that configures the left eyepiece optical system 101L and the right eyepiece optical system 101R in the display apparatus 1.

First Configuration Example

(131) The configuration of the eyepiece according to the first configuration example corresponds to configurations of eyepieces (FIG. 13, etc.) according to Examples 1 to 11 described later. Each of the left eyepiece optical system 101L and the right eyepiece optical system 101R may be configured by an eyepiece of a three-group three-lens configuration in which a first lens L1, a second lens L2, and a third lens L3 are arranged as the plurality of single lenses in order from side of the eye point E.P. toward image side (side of the left-eye image display device 100L or side of the right-eye image display device 100R), as in the eyepieces (FIG. 13, etc.) according to Examples 1 to 11 described later.

(132) In the above-described eyepiece (eyepiece according to the first configuration example) of the three-group three-lens configuration, the first lens L1 is preferably a spherical lens having a positive refractive power including a material of a refractive index of 1.439 or more with respect to ad-line. In addition, a lens surface of the first lens L1 on the side of the eye point E.P. preferably has a convex shape or a planar shape. Causing the first lens L1 to have a positive refractive power and the lens surface on the side of the eye point E.P. to have a convex shape or a planar shape makes it possible to suppress the maximal height of a marginal light beam. This allows for prospects of a reduction in capacitance of the optical system of each of the left eyepiece optical system 101L and the right eyepiece optical system 101R as well as a reduction in weight. In addition, using a spherical lens as the first lens L1 makes it possible to suppress manufacturing costs as compared with the case of using an aspherical lens or a free-form surface lens.

(133) In the eyepiece according to the first configuration example, an optical axis AX (L1) of the first lens L1 is preferably parallel to a reference optical axis AX (E.P.), which employs the eye point E.P. as a reference (see FIGS. 12 and 13, etc. described later). This enables the capacitance of the optical system of each of the left eyepiece optical system 101L and the right eyepiece optical system 101R to be suppressed the most for the same eye relief.

(134) In addition, in the eyepiece according to the first configuration example, at least one of the second lens L2 or the third lens L3 is preferably a free-form surface lens. Using the free-form surface lens makes it possible to favorably correct aberration to be generated.

(135) In addition, in the eyepiece according to the first configuration example, at least one of the first lens L1, the second lens L2, and the third lens L3 is preferably arranged in at least one of an eccentric state or a rotated state with respect to the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference (see FIGS. 12 and 13, etc. described later). In this case, the eyepiece according to the first configuration example preferably satisfies the following conditions.
Si,max<25 (mm)  (1)
θi,max<25(°)  (2)

(136) Here, in the eyepiece according to the first configuration example, si,max denotes the maximum absolute value of an eccentric amount of each of respective optical axes AX (L1), (L2), and (L3) of the first lens L1, the second lens L2, and the third lens L3 with respect to the reference optical axis AX (E.P.) in a direction orthogonal to the reference optical axis AX (E.P.). In addition, in the eyepiece according to the first configuration example, θi,max denotes the maximum absolute value of a rotational amount of each of the respective optical axes AX (L1), (L2), and (L3) of the first lens L1, the second lens L2, and the third lens L3 with respect to the reference optical axis AX (E.P.).

(137) In the eyepiece according to the first configuration example, in a case where there is a lens element in which an eccentric amount and a rotational amount exceed values of the conditional expressions (1) and (2), respectively, the eccentric amount and the rotational amount become too large, thereby increasing a volume of the optical system of each of the left eyepiece optical system 101L and the right eyepiece optical system 101R. This may possibly prevent reduction in size of the entire display apparatus 1, which is not preferable.

Modification Example of First Configuration Example

(138) In contrast to the configuration of the eyepiece according to the first configuration example described above, the optical axis AX (L1) of the first lens L1 may also be configured to be non-parallel, instead of parallel, to the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference, as in a configuration of an eyepiece (FIG. 79) according to Example 23 described later.

(139) In addition, in contrast to the configuration of the eyepiece according to the first configuration example described above, the first lens L1 may also be configured to use a Fresnel lens, instead of a spherical lens, as in the configuration of the eyepiece (FIG. 79) according to Example 23 described later. For example, a lens surface of the first lens L1 on the image side (side opposite to the eye point E.P.) is preferably a Fresnel lens surface.

(140) Using a Fresnel lens as the first lens L1 makes it possible to achieve higher magnification of each of the left eyepiece optical system 101L and the right eyepiece optical system 101R while suppressing increase in the weight of the entire optical system. In addition, it is possible to arrange the first lens L1 to have an optimum eccentric amount and an optimum rotational amount with respect to the FOV described above, thus making it possible to suppress increase in an aperture of the first lens L1. [Second Configuration Example]

(141) A configuration of the eyepiece according to the second configuration example corresponds to configurations of the eyepiece (FIG. 46, etc.) according to Examples 12 to 22 described later. Each of the left eyepiece optical system 101L and the right eyepiece optical system 101R may be configured by an eyepiece of a four-group four-lens configuration in which the first lens L1, the second lens L2, the third lens L3, and a fourth lens L4 are arranged as a plurality of single lenses in order from the side of the eye point E.P. toward the image side (side of the left-eye image display device 100L or side of the right-eye image display device 100R), as in the eyepiece (FIG. 46, etc.) according to Examples 12 to 22 described later.

(142) In the above-described eyepiece (eyepiece according to the second configuration example) of the four-group four-lens configuration, the first lens L1 is preferably a spherical lens having a positive refractive power including a material of a refractive index of 1.439 or more with respect to a d-line. In addition, the lens surface of the first lens L1 on the side of the eye point E.P. preferably has a convex shape or a planar shape. Causing the first lens L1 to have a positive refractive power and the lens surface on the side of the eye point E.P. to have a convex shape or a planar shape makes it possible to suppress the maximal height of a marginal light beam. This allows for prospects of a reduction in capacitance of the optical system of each of the left eyepiece optical system 101L and the right eyepiece optical system 101R as well as a reduction in weight. In addition, using a spherical lens as the first lens L1 makes it possible to suppress manufacturing costs as compared with the case of using an aspherical lens or a free-form surface lens.

(143) In the eyepiece according to the second configuration example, the optical axis AX (L1) of the first lens L1 is preferably parallel to the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference (see FIGS. 12 and 46, etc. described later). This enables the capacitance of the optical system of each of the left eyepiece optical system 101L and the right eyepiece optical system 101R to be suppressed the most for the same eye relief.

(144) In addition, in the eyepiece according to the second configuration example, at least one of the second lens L2, the third lens L3, or the fourth lens L4 is preferably a free-form surface lens. Using the free-form surface lens makes it possible to favorably correct aberration to be generated.

(145) In addition, in the eyepiece according to the second configuration example, at least one of the second lens L2, the third lens L3, or the fourth lens L4 is preferably arranged in at least one of an eccentric state or a rotated state with respect to the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference (see FIGS. 12 and 46, etc. described later). In this case, the eyepiece according to the second configuration example preferably satisfies the following conditions.
Si,max<25 (mm)  (1)
θi,max<25(°)  (2)

(146) Here, in the eyepiece according to the second configuration example, si,max denotes the maximum absolute value of an eccentric amount of each of respective optical axes AX (L1), (L2), (L3), and (L4) of the second lens L2, the third lens L3, and the fourth lens L4 with respect to the reference optical axis AX (E.P.) in a direction orthogonal to the reference optical axis AX (E.P.). In addition, in the eyepiece according to the second configuration example, θi,max denotes the maximum absolute value of a rotational amount of each of the respective optical axes AX (L1), (L2), (L3), and (L4) of the second lens L2, the third lens L3, and the fourth lens L4 with respect to the reference optical axis AX (E.P.).

(147) In the eyepiece according to the second configuration example, in a case where there is a lens element in which an eccentric amount and a rotational amount exceed values of the conditional expressions (1) and (2), respectively, the eccentric amount and the rotational amount become too large, thereby increasing a volume of the optical system of each of the left eyepiece optical system 101L and the right eyepiece optical system 101R. This may possibly prevent reduction in size of the entire display apparatus 1, which is not preferable.

Modification Example of Second Configuration Example

(148) In contrast to the configuration of the eyepiece according to the second configuration example described above, the optical axis AX (L1) of the first lens L1 may also be configured to be non-parallel, instead of parallel, to the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference, as in a configuration of an eyepiece (FIG. 82) according to Example 24 described later.

(149) In addition, in contrast to the configuration of the eyepiece according to the second configuration example described above, the first lens L1 may also be configured to use a Fresnel lens, instead of a spherical lens, as in the configuration of the eyepiece (FIG. 82) according to Example 24 described later. For example, a lens surface of the first lens L1 on the image side (side opposite to the eye point E.P.) is preferably a Fresnel lens surface.

(150) Using a Fresnel lens as the first lens L1 makes it possible to achieve higher magnification of each of the left eyepiece optical system 101L and the right eyepiece optical system 101R while suppressing increase in the weight of the entire optical system. In addition, it is possible to arrange the first lens L1 to have an optimum eccentric amount and an optimum rotational amount with respect to the FOV described above, thus making it possible to suppress increase in the aperture of the first lens L1. [Third Configuration Example]

(151) FIG. 85 illustrates an overview of a third configuration example of an eyepiece according to an embodiment. The configuration of the eyepiece according to the third configuration example corresponds to configurations of eyepieces (FIGS. 86 and 87) according to Example 25 described later.

(152) In contrast to the configurations of the eyepieces according to the first and second configuration examples described above, a configuration including a varifocal lens group may be employed. For example, as in the eyepiece according to the third configuration example illustrated in FIG. 85, a configuration may be employed which includes an eccentric lens group G1 and a varifocal lens group G2 in order from the side of the eye point E.P. toward the image side. Each of the eccentric lens group G1 and the varifocal lens group G2 is configured by a plurality of single lenses, for example.

(153) The varifocal lens group G2 may be configured by an Alvarez lens, for example. The Alvarez lens is able to change a focal length by moving two lenses mutually in a direction different from an optical axis.

(154) The varifocal lens group G2 is preferably arranged in eccentric and rotated states with respect to the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference. In a case where the varifocal lens group G2 is configured by the Alvarez lens, for example, the two lenses are moved mutually in directions opposite to each other and in directions different from the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference, thereby making it possible to change the focal length.

(155) The eyepiece according to the third configuration example is configured to include the varifocal lens group G2, thereby enabling adjustment of visibility. This makes it possible to provide an image corresponding to a user having a wide range of visual acuity (e.g., 0.1 or more). In addition, it becomes unnecessary to ensure an eye relief (e.g., 15 mm) which assumes a user of glasses. For this reason, higher FOV, higher definition, and reduced weight of the optical system are expected as ripple effects as a result of shorter eye relief.

Effects of Invention

(156) According to the display apparatus of an embodiment of the present disclosure, the configuration of the lenses is optimized that configure the left eyepiece optical system 101L and the right eyepiece optical system 101R, and the non-overlap image region 12 is included in the left-eye display image 10L and the right-eye display image 10R. This makes it possible to achieve a lighter weight and a wider angle of view upon observation by both eyes without causing a concern about generation of stray light and to provide high-definition beauty of an image.

(157) In particular, each of the left eyepiece optical system 101L and the right eyepiece optical system 101R is configured by the plurality of single lenses including a free-form surface lens including a resin material to optimize the configuration of each lens, thereby achieving a lighter weight without causing the concern about the generation of stray light. In addition, use of the resin material makes it possible to suppress material costs and manufacturing costs. In addition, at least one of the plurality of single lenses is arranged in at least one of an eccentric state or a rotated state with respect to the optical axis of the left-eye image display device 100L or the right-eye image display device 100R, and the non-overlap image region 12, which constitutes a region outside the overlap image region 11, is included in each of the left-eye display image 10L and the right-eye display image 10R. This makes it possible to achieve a wider angle of view upon observation by both eyes.

(158) Applying the display apparatus according to an embodiment to a head-mounted display makes it possible to provide high-definition beauty of an image at a high viewing angle. In a head-mounted display having a high viewing angle, a pupil position shifts when observing a peripheral region of an image (hereinafter, referred to as “eye shift”). At this time, it is difficult to secure desired optical characteristics for an amount of the eye shift assumed in the head-mounted display. According to the display apparatus of an embodiment, configuring the left eyepiece optical system 101L and the right eyepiece optical system 101R as described above makes it possible to achieve an optical system that is robust against the eye shift.

(159) It is to be noted that the effects described herein are merely illustrative and non-limiting, and may have other effects.

3. Example of Application to Head-Mounted Display

(160) FIGS. 92 and 93 illustrate a configuration example of a head-mounted display 200 to which the display apparatus 1 according to an embodiment of the present disclosure is applied. The head-mounted display 200 includes a body 201, a forehead rest 202, a nose rest 203, a headband 204, and headphones 205. The forehead rest 202 is provided at an upper-middle part of the body 201. The nose rest 203 is provided at a lower-middle part of the body 201.

(161) When the user wears the head-mounted display 200 on the head, the forehead rest 202 abuts the forehead of the user, and the nose rest 203 abuts the nose. Further, the headband 204 abuts the rear of the head. As a result, the head-mounted display 200 distributes a load of the apparatus over the entire head. This makes it possible for the user to wear the head-mounted display 200 with a less burden on the user.

(162) The headphones 205 are provided for the left ear and the right ear. This makes it possible to provide sounds to the left ear and the right ear independently.

(163) The body 201 is provided with a circuit board, an optical system, etc. that are built in the body 201 and are adapted to display an image. As illustrated in FIG. 93, a left-eye display part 210L and a right-eye display part 210R are provided in the body 201. This makes it possible to provide images to the left eye and the right eye independently. The left-eye display part 210L is provided with a left eyepiece display unit including an image display device for the left eye and an eyepiece optical system for the left eye that magnifies an image displayed on the image display device for the left eye. The right-eye display part 210R is provided with a right eyepiece display unit including an image display device for the right eye and an eyepiece optical system for the right eye that magnifies an image displayed on the image display device for the right eye. The left eyepiece display unit 102L and the right eyepiece display unit 102R in the display apparatus 1 according to an embodiment of the present disclosure are applicable as the left eyepiece display unit configuring the left-eye display part 210L and the right eyepiece display unit configuring the right-eye display part 210R.

(164) It is to be noted that image data is supplied to the image display device from an unillustrated image reproducing apparatus. It is also possible to perform three-dimensional display by supplying three-dimensional image data from the image reproducing apparatus and displaying images having parallaxes with respect to each other by means of the left-eye display part 210L and the right-eye display part 210R.

EXAMPLES

Overview of Examples

(165) FIG. 11 schematically illustrates a relationship between magnitude of a field angle of view (FOV) as well as magnitude of an eye relief E.R. and a height of a light beam (marginal light beam) passing an outermost of a first surface of an eyepiece.

(166) As illustrated in FIG. 11, increasing the field angle of view and the eye relief E.R. causes the height of the marginal light beam at the first surface of the eyepiece to increase. In a case of considering that the marginal light beam is caused to form an image on an equally-sized image display device, the light beam needs to be bent greater, as the height of the light beam increases. Accordingly, the amount of generation of aberration increases, thus causing the imaging-forming capability to be lowered. In this manner, the magnitude of each of the field angle of view and the eye relief E.R. is in a trade-off relationship with the imaging-forming capability.

(167) In consideration of such characteristics, the following examples illustrate design examples of specifications in which the magnitudes of the field angle of view and the eye relief E.R. are changed as illustrated in Tables 1 and 2. Here, Examples 1 to 11 and 23 correspond to the eyepiece (eyepiece of three-group three-lens configuration) of the foregoing first configuration example and modification example thereof. Examples 12 to 22 and 24 correspond to the eyepiece (eyepiece of four-group four-lens configuration) of the foregoing second configuration example and modification example thereof. Example 25 corresponds to the eyepiece (eyepiece of the configuration including the varifocal lens group G2) of the foregoing third configuration example. As illustrated in Tables 1 and 2, in each of the eyepiece of the three-group three-lens configuration and the eyepiece of the four-group four-lens configuration, the lens surface of the first lens L1 on the side of the eye point E.P. exhibits examples of a convex shape and examples of a planar shape. In addition, as illustrated in Tables 1 and 2, design examples are exhibited in which the number of the free-form surface lenses is changed in each of the eyepiece of the three-group three-lens configuration and the eyepiece of the four-group four-lens configuration.

(168) It is to be noted that, as illustrated in the above-mentioned FIG. 9, as for the field angle of view, the maximum angle of view of one side (left side or right side), upon observation by a single eye, with reference to the front gaze point (C0L, C0R) is defined as θa, and the maximum angle of view of the other side (right side or left side) is defined as θb (θa>θb). θb corresponds to the maximum angle of view of the overlap image region 11. As for the maximum angle of view upon observation by both eyes, the maximum angle of view is θa on both the left side and the right side with reference to the front gaze point C0, as illustrated in the above-mentioned FIG. 10.

(169) TABLE-US-00001 TABLE 1 Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple 1 2 3 4 5 6 Lens Config- 3-Group 3-Group 3-Grow 3-Grow 3-Grow 3-Grow uration 3-Lens 3-Lens 3-Lens 3-Lens 3-Lens 3-Lens FOV θa [degree] 55.0 55.0 55.0 57.5 57.5 57.5 θb [degree] 40 40 40 40 40 40 Eye Relief 11 13 15 11 13 15 E.R. [mm] Shape of L1 Con- Con- Con- Con- Con- Con- on E.P. Side vex vex vex vex vex vex Number of 1 1 1 1 1 1 Free-Form Surface Lens Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple 7 8 9 10 11 23 Lens Config- 3-Group 3-Group 3-Grow 3-Grow 3-Grow 3-Grow uration 3-Lens 3-Lens 3-Lens 3-Lens 3-Lens 3-Lens FOV θa [degree] 60.0 60.0 60.0 55.0 55.0 70.0 θb [degree] 40 40 40 40 40 40 Eye Relief 11 13 15 11 11 10 E.R. [mm] Shape of L1 Con- Con- Con- Flat Con- Con- on E.P. Side vex vex vex vex vex Number of 1 1 1 1 2 1 Free-Form Surface Lens

(170) TABLE-US-00002 TABLE 2 Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple 12 13 14 15 16 17 Lens Config- 4-Group 4-Group 4-Grow 4-Grow 4-Grow 4-Grow uration 4-Lens 4-Lens 4-Lens 4-Lens 4-Lens 4-Lens FOV θa [degree] 55.0 55.0 55.0 57.5 57.5 57.5 θb [degree] 40 40 40 40 40 40 Eye Relief 11 13 15 11 13 15 E.R. [mm] Shape of L1 Con- Con- Con- Con- Con- Con- on E.P. Side vex vex vex vex vex vex Number of 1 1 1 1 1 1 Free-Form Surface Lens Exam- Exam- Exam- Exam- Exam- Exam- ple ple ple ple ple ple 18 19 20 21 22 24 Lens Config- 4-Group 4-Group 4-Grow 4-Grow 4-Grow 4-Grow uration 4-Lens 4-Lens 4-Lens 4-Lens 4-Lens 4-Lens FOV θa [degree] 60.0 60.0 60.0 55.0 55.0 70.0 θb [degree] 40 40 40 40 40 40 Eye Relief 11 13 15 11 11 10 E.R. [min] Shape of L1 Con- Con- Con- Flat Con- Con- on E.P. Side vex vex vex vex vex Number of 1 1 1 1 3 2 Free-Form Surface Lens Example 25 Lens Configuration 5-Group 5-Lens FOV θa [degree] 65.0 θb [degree] 40 Eye Relief E.R. [mm] 10 Shape of L1 on E.P. Side Convex Number of Free-Form 3 Surface Lens

4. Numerical Examples of Eyepiece Optical System (Eyepiece)

(171) Specific lens data of eyepieces according to respective examples exhibited in Tables 1 and 2 are given below. The eyepiece according to each of the examples corresponds to each of the left eyepiece optical system 101L and the right eyepiece optical system 101R, and is applied to each of the left eyepiece display unit 102L and the right eyepiece display unit 102R. In the eyepiece according to each of the examples, the left-eye image display device 100L or the right-eye image display device 100R is referred to as the image display device 100 without distinction between the left and the right.

(172) It is to be noted that meanings, etc. of symbols used in the following tables and descriptions are as follows. “Si” denotes the number of i-th surface, which is numbered to sequentially increase toward the image side, with the eye point E.P. being numbered as the first. “Ri” denotes a paraxial curvature radius (mm) of the i-th surface. “Ndi” denotes a value of a refractive index at a d-line (a wavelength of 587.6 nm) of a material (medium) of an optical element having the i-th surface. “vdi” denotes a value of Abbe's number at the d-line of the material of the optical element having the i-th surface. A surface having a curvature radius of “o” indicates a planar surface or a stop surface (an aperture stop STO (eye point E.P.)).

Description of Definitions of Eccentric Amount, Rotational Amount, and Interval

(173) FIG. 12 illustrates a definition of an optical axis of the eyepiece according to each of the examples. In the eyepiece according to each of the embodiments, at least one lens element and the image display device 100 are eccentric and/or rotated with respect to the eye point E.P. It is to be noted that, FIG. 12 exemplifies the eyepiece of the three-group three-lens configuration, but the same applies also to the eyepiece, etc. of the four-group four-lens configuration.

(174) In each of the examples, as illustrated in FIG. 12, (Y-coordinate and Z-coordinate) of the eye point E.P. is set to (0, 0), and the optical axis AX (E.P.) of the eye point E.P. is set as a reference optical axis. In addition, an optical axis of an i-th lens Li is represented as an optical axis AX (Li). An optical axis of the image display device 100 is represented as AX (Pa). As for the positions of each lens element and the image display device 100 in the following tables, absolute positions (Y-coordinate and Z-coordinate) are indicated on each optical axis in a case where the eye point E.P. is set to (0,0). In addition, similarly, also for the rotational amount, an absolute amount is indicated with reference to the optical axis AX (E.P.) of eye point E.P.

Description of Definition of Image Magnification

(175) The image magnification My is defined as Mv=α′/α as described above referring to FIG. 3; in the eyepiece according to each of the examples, at least one lens element and the image display device 100 are eccentric and/or rotated with respect to the eye point E.P. Accordingly, an observation angle is asymmetric with respect to an eccentric direction and a rotational direction. In the present example, in order to handle the observation angle in an average manner, the image magnification My was calculated using an observation angle in a case of replacing a Y-position and a rotational amount of the image display device 100 with 0 (mm) and 0 (degree), respectively, while keeping a Z-position thereof as it is.

(176) (Expressions of Aspherical Surface and Free-Form Surface)

(177) The eyepiece according to each of the examples includes a free-form surface lens. In addition, an aspherical lens may be included in some cases. An aspherical shape is defined by the following expression (1.1) of an aspherical surface. In addition, a free-form surface shape is defined by the following expression (1.2) of a free-form surface. It is to be noted that, in each of the following tables exhibiting aspherical surfaces and free-form surfaces, “E-n” denotes an exponential expression with a base of 10, i.e., “minus n-th power of 10”. For example, “0.12345E-05” denotes “0.12345×(minus fifth power of 10)”.

(178) $\begin{array}{cc}\mathrm{Za}\left(s\right)=\frac{\frac{1}{R}{s}^2}{1+\sqrt{1-\left(1+k\right)\frac{1}{R^2}{s}^2}}+A4s^4+A6s^6+A8s^8+\mathrm{.Math.}& \left(1.1\right)\\ \mathrm{Zf}\left(s\right)=\frac{\frac{1}{R}{s}^2}{1+\sqrt{1-\left(1+k\right)\frac{1}{R^2}{s}^2}}+B1.Math.x^1{y}^0+B2.Math.x^0{y}^1+B3.Math.x^2{y}^0+B4.Math.x^1{y}^1+B5.Math.x^0{y}^2+\mathrm{.Math.}& \left(1.2\right)\end{array}$

(179) In the expressions,

(180) Za (s) denotes a sag amount of an aspherical shape with reference to an optical axis of each lens element,

(181) Zf (s) denotes a sag amount of a free-form surface shape with reference to an optical axis of each lens element,

(182) s denotes a distance from an optical axis of each lens element (tangential direction),

(183) x denotes a distance from an optical axis of each lens element (x-direction, see FIG. 4),

(184) y denotes a distance from an optical axis of each lens element (z-direction, see FIG. 4),

(185) R denotes a curvature radius,

(186) k denotes a conic constant,

(187) Ai denotes an aspherical coefficient of degree i, and

(188) Bj denotes a j-th polynomial coefficient.

Example 1

(189) Table 3 exhibits basic lens data of an eyepiece according to Example 1. In addition, Table 4 exhibits data of polynomials representing a free-form surface.

(190) TABLE-US-00003 TABLE 3 Example 1 Lens Data Si Surface Yi Y- Zi Z- θi Rotational Ri Curvature Ndi Refractive νdi Abbe's No. Coordinate Coordinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 3.068 11.000 0.000 117.55 1.439 94.7 3 3.068 17.840 0.000 −23.594 — — 4 −4.125 19.475 −16.931 30.743 1.883 40.8 5 −1.438 28.302 −16.931 66.256 — — 6 4.672 28.145 −3.546 ∞ 1.661 20.4 7 5.336 38.862 −3.546 ∞ — — 8 4.456 44.133 −1.542 ∞ — —

(191) TABLE-US-00004 TABLE 4 Example 1 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 — −1.049E−02 1.622E−02 — 1.734E−02 7 1.000 — −3.454E−02 1.267E−03 — 1.585E−02 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −6.660E−04 — −7.088E−05  1.947E−08 — 7 —  1.061E−04 —  1.438E−04 −5.462E−07 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 −4.343E−07 — −7.021E−07 — −6.229E−08 — 7  1.630E−06 — −5.819E−08 —  4.693E−08 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6 8.976E−08 — −1.408E−07 7 1.764E−07 — −4.885E−08

(192) FIG. 13 illustrates a lens cross-section of the eyepiece according to Example 1. FIGS. 14 to 15 illustrate various aberrations of the eyepiece according to Example 1. Each aberration is obtained by tracing a light beam from the side of the eye point E.P. In particular, FIG. 14 illustrates astigmatism (field curvature) and distortion. FIG. 15 illustrates chromatic aberration of magnification. An astigmatism diagram and a distortion diagram indicate a value for a wavelength of 587.6 (nm). In the astigmatism diagram, S denotes a value on a sagittal image plane, and T denotes a value on a tangential image plane. A diagram of chromatic aberration of magnification indicates values for a wavelength of 486.1 (nm) and a wavelength of 656.3 (nm), with the wavelength of 587.6 (nm) as a reference wavelength.

(193) It is to be noted that each aberration diagram illustrates aberrations in a case where alight beam tracing angle is changed in ay-direction (see FIG. 5). The same holds true also for aberration diagrams in other examples below.

(194) As can be appreciated from each of the aberration diagrams, it is obvious that Example 1 exhibits favorable optical performance.

Example 2

(195) Table 5 exhibits basic lens data of an eyepiece according to Example 2. In addition, Table 6 exhibits data of polynomials representing a free-form surface.

(196) TABLE-US-00005 TABLE 5 Example 2 Lens Data Si Surface Yi Y- Zi Z- θi Rotational Ri Curvature Ndi Refractive νdi Abbe's No. Coordinate Coordinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 9.610 13.000 0.000 100.774 1.963 24.1 3 9.610 20.678 0.000 −81.970 — — 4 1.420 22.801 −16.180 31.526 1.877 40.8 5 4.207 32.405 −16.180 107.653 — — 6 3.196 33.967 −21.124 ∞ 1.661 20.4 7 6.597 42.768 −21.124 ∞ — — 8 8.571 46.980 −15.557 ∞ — —

(197) TABLE-US-00006 TABLE 6 Example 2 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  1.848E−01 1.740E−02 — 7.679E−03 7 1.000 — −1.348E−01 1.363E−03 — 7.594E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −3.376E−04 — −9.993E−05 1.210E−05 — 7 — −5.174E−04 —  1.268E−04 1.057E−07 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 −1.013E−06 —  8.241E−06 — −1.547E−06 — 7  1.442E−05 — −1.182E−05 —  6.905E−07 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6 7.160E−07 — −9.968E−08 7 5.755E−07 —  5.268E−07

(198) FIG. 16 illustrates a lens cross-section of the eyepiece according to Example 2. FIGS. 17 to 18 illustrate various aberrations of the eyepiece according to Example 2.

(199) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 2 has favorable optical performance.

Example 3

(200) Table 7 exhibits basic lens data of an eyepiece according to Example 3. In addition, Table 8 exhibits data of polynomials representing a free-form surface.

(201) TABLE-US-00007 TABLE 7 Example 3 Lens Data Si Surface Yi Y- Zi Z- θi Rotational Ri Curvature Ndi Refractive νdi Abbe's No. Coordinate Coordinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 4.419 15.000 0.000 117.898 1.963 24.1 3 4.419 21.000 0.000 −63.595 — — 4 3.474 21.987 −6.712 36.807 1.883 40.8 5 4.092 27.237 −6.712 68.665 — — 6 2.556 28.402 −20.433 ∞ 1.661 20.4 7 6.863 39.964 −20.433 ∞ — — 8 7.064 46.421 −7.516 ∞ — —

(202) TABLE-US-00008 TABLE 8 Example 3 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  1.867E−01  1.995E−02 —  1.599E−02 7 1.000 — −1.686E−02 −2.022E−03 — −8.243E−04 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −2.152E−04 — −1.233E−04 −5.823E−07 — 7 — −1.792E−05 —  1.523E−04 −2.820E−08 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 1.429E−06 — 4.564E−06 — −5.170E−07 — 7 9.605E−06 — 1.703E−06 —  6.917E−08 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6 9.236E−08 — −2.292E−07 7 7.955E−08 — −8.027E−08

(203) FIG. 19 illustrates a lens cross-section of the eyepiece according to Example 3. FIGS. 20 to 21 illustrate various aberrations of the eyepiece according to Example 3.

(204) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 3 has favorable optical performance.

Example 4

(205) Table 9 exhibits basic lens data of an eyepiece according to Example 4. In addition, Table 10 exhibits data of polynomials representing a free-form surface.

(206) TABLE-US-00009 TABLE 9 Example 4 Lens Data Si Surface Yi Y- Zi Z- θi Rotational Ri Curvature Ndi Refractive νdi Abbe's No. Coordinate Coordinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 10.305 11.000 0.000 90.820 1.963 24.1 3 10.305 18.328 0.000 −85.996 — — 4 1.475 20.545 −17.590 31.077 1.883 40.8 5 4.497 30.077 −17.590 107.953 — — 6 5.490 31.649 −22.975 ∞ 1.661 20.4 7 8.526 38.809 −22.975 ∞ — — 8 8.995 43.683 −16.386 ∞ — —

(207) TABLE-US-00010 TABLE 10 Example 4 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  2.470E−01  1.904E−02 — 5.829E−03 7 1.000 — −1.048E−01 −2.424E−05 — 6.589E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −4.424E−04 — −1.444E−04 1.104E−05 — 7 — −5.535E−04 —  9.045E−05 1.135E−05 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 −3.767E−06 —  1.061E−05 — −2.438E−06 — 7  1.475E−05 — −5.901E−06 —  1.094E−06 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6 6.333E−07 — 2.238E−08 7 8.520E−08 — 5.317E−07

(208) FIG. 22 illustrates a lens cross-section of the eyepiece according to Example 4. FIGS. 23 to 24 illustrate various aberrations of the eyepiece according to Example 4.

(209) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 4 has favorable optical performance.

Example 5

(210) Table 11 exhibits basic lens data of an eyepiece according to Example 5. In addition, Table 12 exhibits data of polynomials representing a free-form surface.

(211) TABLE-US-00011 TABLE 11 Example 5 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 5.303 13.000 0.000 120.654 1.963 24.1 3 5.303 18.697 0.000 −57.614 — — 4 2.218 19.693 −7.535 30.891 1.883 40.8 5 3.024 25.783 −7.535 47.292 — — 6 3.043 26.788 −24.657 ∞ 1.661 20.4 7 7.796 37.142 −24.657 ∞ — — 8 6.486 43.728 −11.536 ∞ — —

(212) TABLE-US-00012 TABLE 12 Example 5 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  2.552E−01  1.857E−02 — 1.427E−02 7 1.000 — −1.738E−02 −9.378E−04 — 5.698E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −1.353E−04 — 1.172E−05  1.190E−05 — 7 —  3.387E−04 — 1.652E−04  5.166E−06 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 2.346E−05 —  1.096E−05 — −4.930E−07 — 7 4.088E−06 —  2.767E−07 — −1.302E−07 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6  1.210E−06 —  2.685E−08 7 −1.710E−07 — −3.769E−08

(213) FIG. 25 illustrates a lens cross-section of the eyepiece according to Example 5. FIGS. 26 to 27 illustrate various aberrations of the eyepiece according to Example 5.

(214) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 5 has favorable optical performance.

Example 6

(215) Table 13 exhibits basic lens data of an eyepiece according to Example 6. In addition, Table 14 exhibits data of polynomials representing a free-form surface.

(216) TABLE-US-00013 TABLE 13 Example 6 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 6.102 15.000 0.000 144.881 1.963 24.1 3 6.102 21.672 0.000 −58.056 — — 4 6.175 22.642 −2.564 31.881 1.883 40.8 5 6.562 31.288 −2.564 68.988 — — 6 4.375 32.372 −15.548 ∞ 1.661 20.4 7 7.797 44.670 −15.548 ∞ — — 8 8.108 48.477 −7.653 ∞ — —

(217) TABLE-US-00014 TABLE 14 Example 6 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  1.520E−01  1.803E−02 — 1.608E−02 7 1.000 — −2.101E−02 −6.245E−03 — 2.661E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −7.265E−05 —  1.107E−04  6.109E−06 — 7 — −3.278E−05 —  8.072E−05  1.103E−05 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 −3.507E−05 —  1.130E−05 — −4.401E−07 — 7  1.313E−05 —  2.110E−06 —  1.861E−07 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6  2.703E−07 — −1.934E−07 7 −3.533E−07 —  1.185E−07

(218) FIG. 28 illustrates a lens cross-section of the eyepiece according to Example 6. FIGS. 29 to 30 illustrate various aberrations of the eyepiece according to Example 6.

(219) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 6 has favorable optical performance.

Example 7

(220) Table 15 exhibits basic lens data of an eyepiece according to Example 7. In addition, Table 16 exhibits data of polynomials representing a free-form surface.

(221) TABLE-US-00015 TABLE 15 Example 7 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 8.164 11.000 0.000 106.869 1.963 24.1 3 8.164 17.071 0.000 −69.691 — — 4 2.550 18.691 −12.402 31.990 1.883 40.8 5 4.148 25.956 −12.402 95.134 — — 6 4.017 27.007 −22.859 ∞ 1.661 20.4 7 7.727 35.806 −22.859 ∞ — — 8 7.655 41.528 −15.229 ∞ — —

(222) TABLE-US-00016 TABLE 16 Example 7 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  2.434E−01  1.778E−02 — 9.768E−03 7 1.000 — −9.913E−02 −9.620E−04 — 6.362E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −2.761E−04 — −2.649E−05  1.220E−05 — 7 — −2.757E−04 —  1.125E−04  9.131E−06 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 5.701E−06 —  9.602E−06 — −1.386E−06 — 7 1.242E−05 — −2.344E−06 —  6.675E−07 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6 5.079E−07 — −3.483E−08 7 5.504E−08 —  2.161E−07

(223) FIG. 31 illustrates a lens cross-section of the eyepiece according to Example 7. FIGS. 32 to 33 illustrate various aberrations of the eyepiece according to Example 7.

(224) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 7 has favorable optical performance.

Example 8

(225) Table 17 exhibits basic lens data of an eyepiece according to Example 8. In addition, Table 18 exhibits data of polynomials representing a free-form surface.

(226) TABLE-US-00017 TABLE 17 Example 8 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 6.087 13.000 0.000 145.639 1.963 24.1 3 6.087 18.690 0.000 −58.772 — — 4 4.637 19.700 −6.076 34.456 1.883 40.8 5 5.528 28.073 −6.076 106.086 — — 6 5.225 29.094 −16.363 ∞ 1.661 20.4 7 8.727 41.023 −16.363 ∞ — — 8 8.156 45.036 −10.397 ∞ — —

(227) TABLE-US-00018 TABLE 18 Example 8 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  1.881E−01  1.874E−02 — 1.538E−02 7 1.000 — −9.178E−02 −1.280E−03 — 1.310E−04 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −4.576E−05 —  1.627E−05  1.134E−05 — 7 — −1.994E−05 —  2.069E−04  6.041E−06 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 −3.447E−06 —  3.054E−06 — −1.192E−06 — 7  1.639E−05 —  4.083E−06 —  3.124E−07 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6  6.740E−08 — −4.197E−07 7 −3.351E−07 — −2.053E−07

(228) FIG. 34 illustrates a lens cross-section of the eyepiece according to Example 8. FIGS. 35 to 36 illustrate various aberrations of the eyepiece according to Example 8.

(229) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 8 has favorable optical performance.

Example 9

(230) Table 19 exhibits basic lens data of an eyepiece according to Example 9. In addition, Table 20 exhibits data of polynomials representing a free-form surface.

(231) TABLE-US-00019 TABLE 19 Example 9 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 6.650 15.000 0.000 455.108 1.963 24.1 3 6.650 21.749 0.000 −43.366 — — 4 7.554 22.538 −4.101 35.315 1.883 40.8 5 8.150 30.848 −4.101 124.555 — — 6 7.178 31.691 −9.970 ∞ 1.661 20.4 7 9.190 43.134 −9.970 ∞ — — 8 8.588 47.901 −5.568 ∞ — —

(232) TABLE-US-00020 TABLE 20 Example 9 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  9.748E−02  1.623E−02 —  9.174E−03 7 1.000 — −1.451E−01 −7.876E−03 — −1.578E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −2.910E−04 —  1.909E−05 −6.615E−07 — 7 —  9.549E−05 —  1.558E−04  9.511E−06 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 −1.191E−05 —  6.147E−06 — −1.063E−07 — 7  1.676E−05 —  6.500E−07 —  5.331E−08 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6  5.896E−09 — −7.203E−08 7 −6.427E−07 —  7.155E−08

(233) FIG. 37 illustrates a lens cross-section of the eyepiece according to Example 9. FIGS. 38 to 39 illustrate various aberrations of the eyepiece according to Example 9.

(234) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 9 has favorable optical performance.

Example 10

(235) Table 21 exhibits basic lens data of an eyepiece according to Example 10. In addition, Table 22 exhibits data of polynomials representing a free-form surface.

(236) TABLE-US-00021 TABLE 21 Example 10 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 −4.846 11.000  0.000 ∞ 1.883 40.8 3 −4.846 17.644  0.000 −52.074 — — 4 −4.968 18.643 −13.673  44.962 1.963 24.1 5 −3.477 24.771 −13.673 146.53  — — 6  2.357 25.803  7.818 ∞ 1.661 20.4 7  0.728 37.669  7.818 ∞ — — 8  1.991 44.822  5.663 ∞ — —

(237) TABLE-US-00022 TABLE 22 Example 10 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 — −9.072E−02  1.664E−02 — 1.348E−02 7 1.000 —  2.704E−01 −9.567E−03 — 8.981E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — 4.352E−04 — −1.428E−04 −2.783E−06 — 7 — 1.224E−04 —  6.393E−05  4.744E−06 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 3.222E−05 —  2.186E−06 — 1.901E−07 — 7 4.340E−05 — −1.834E−05 — 1.715E−07 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 6 1.563E−07 —  3.928E−07 7 7.564E−07 — −4.527E−07

(238) FIG. 40 illustrates a lens cross-section of the eyepiece according to Example 10. FIGS. 41 to 42 illustrate various aberrations of the eyepiece according to Example 10.

(239) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 10 has favorable optical performance.

Example 11

(240) Table 23 exhibits basic lens data of an eyepiece according to Example 11. In addition, Table 24 exhibits data of polynomials representing a free-form surface.

(241) TABLE-US-00023 TABLE 23 Example 11 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 3.002 11.000 0.000 66.331 1.883 40.8 3 3.002 15.715 0.000 −84.880 — — 4 4.449 16.714 −4.301 ∞ 1.553 56.0 5 5.199 26.679 −4.301 ∞ — — 6 4.920 27.703 −2.842 ∞ 1.553 56.0 7 5.430 37.985 −2.842 ∞ — — 8 4.778 43.297 −5.411 ∞ — —

(242) TABLE-US-00024 TABLE 24 Example 11 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 4 1.000 —  3.418E−02  1.102E−02 — 1.699E−02 5 1.000 — −1.173E−01 −1.027E−02 — 8.020E−04 6 1.000 —  1.282E−02  1.034E−02 — 1.259E−02 7 1.000 — −1.326E−01 −1.967E−02 — 5.867E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 4 — −1.099E−04 —  1.149E−05 −1.497E−05 — 5 —  2.093E−04 —  5.762E−05  1.191E−05 6 — −1.995E−05 — −1.965E−04 −6.439E−06 — 7 — −8.895E−06 — −2.080E−04 −7.325E−07 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 4  6.347E−06 —  7.432E−06 — −9.015E−08 — 5  8.445E−07 — −3.513E−06 —  2.770E−07 — 6  8.070E−06 — −1.278E−05 — −1.511E−07 — 7  5.109E−05 —  7.038E−07 — −7.652E−08 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 4 −1.082E−06 — −9.090E−08 5 −9.540E−07 —  3.590E−07 6  1.877E−06 —  7.667E−07 7  4.346E−07 — −7.416E−08

(243) FIG. 43 illustrates a lens cross-section of the eyepiece according to Example 11. FIGS. 44 to 45 illustrate various aberrations of the eyepiece according to Example 11.

(244) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 11 has favorable optical performance.

Example 12

(245) Table 25 exhibits basic lens data of an eyepiece according to Example 12. In addition, Table 26 exhibits aspherical surface data. In addition, Table 27 exhibits data of polynomials representing a free-form surface.

(246) TABLE-US-00025 TABLE 25 Example 12 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number  1 — — — ∞ — — (STO)  2 2.621 11.000 0.000 82.238 1.439 94.7  3 2.621 16.191 0.000 −51.611 — —  4 1.170 17.204 6.359 46.290 1.877 40.8  5 1.660 21.598 −6.359 116.776 — —  6 3.398 22.387 −2.321 27.015 1.661 20.4  7 3.770 31.559 −2.321 ∞ — —  8 3.943 33.542 −0.443 ∞ 1.553 56.0  9 4.009 42.077 −0.443 ∞ — — 10 3.553 45.982 −3.046 ∞ — —

(247) TABLE-US-00026 TABLE 26 Example 12 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6 −1.479E+00   1.853E−06 −1.163E−09 −3.097E−12 7 0.000E+00 −1.659E−06   −1.132E−09   3.141E−12

(248) TABLE-US-00027 TABLE 27 Example 12 Free-Form Surface Data r Si Normalized Surface No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 8 1.000 — 1.293E−01   7.061E−03 —   7.641E−03 9 1.000 — 4.285E−03 −6.969E−03 — −6.120E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 8 — −1.943E−04 — −1.263E−04 9 — −1.290E−05 — −5.333E−05

(249) FIG. 46 illustrates a lens cross-section of the eyepiece according to Example 12. FIGS. 47 to 48 illustrate various aberrations of the eyepiece according to Example 12.

(250) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 12 has favorable optical performance.

Example 13

(251) Table 28 exhibits basic lens data of an eyepiece according to Example 13. In addition, Table 29 exhibits aspherical surface data. In addition, Table 30 exhibits data of polynomials representing a free-form surface.

(252) TABLE-US-00028 TABLE 28 Example 13 Lens Data Yi Zi θi Ri Ndi Si Y- Z- Rota- Curva- Re- vdi Surface Coor- Coor- tional ture fractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 2.516 13.000 0.000 169.491 1.963 24.1 3 2.516 18.325 0.000 −52.997 — — 4 3.068 19.283 −3.871 33.826 1.877 40.8 5 3.496 25.619 −3.871 113.512 — — 6 2.275 26.631 −3.042 56.955 1.661 20.4 7 2.813 36.764 −3.042 1208.724 — — 8 3.471 38.737 0.237 ∞ 1.553 56.0 9 3.448 44.344 0.237 ∞ — — 10 3.734 46.374 −4.315 ∞ — —

(253) TABLE-US-00029 TABLE 29 Example 13 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6 1.850E+00 1.063E−06 −1.540E−09 −3.273E−12 7 2.562E+03 3.877E−07   3.155E−09   7.262E−12

(254) TABLE-US-00030 TABLE 30 Example 13 Free-Form Surface Data r Si Normalized Surface No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 8 1.000 —   6.856E−03   3.314E−03 — 4.035E−03 9 1.000 — −5.687E−03 −2.512E−03 — 9.521E−04 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 8 — −2.332E−04 —   1.804E−06 9 —   7.197E−06 — −7.216E−05

(255) FIG. 49 illustrates a lens cross-section of the eyepiece according to Example 13. FIGS. 50 to 51 illustrate various aberrations of the eyepiece according to Example 13.

(256) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 13 has favorable optical performance.

Example 14

(257) Table 31 exhibits basic lens data of an eyepiece according to Example 14. In addition, Table 32 exhibits aspherical surface data. In addition, Table 33 exhibits data of polynomials representing a free-form surface.

(258) TABLE-US-00031 TABLE 31 Example 14 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 3.854 15.000 0.000 178.931 1.963 24.1 3 3.854 21.534 0.000 −46.746 — — 4 4.217 22.444 −5.515 34.235 1.877 40.8 5 4.85  28.999 −5.515 108.170 — — 6 3.255 30.087 −7.004 52.885 1.661 20.4 7 4.328 38.823 −.004 1222.183 — — 8 5.850 40.579 −5.044 ∞ 1.553 56.0 9 6.362 46.369 −5.044 ∞ — — 10 6.499 48.077 −6.876 ∞ — —

(259) TABLE-US-00032 TABLE 32 Example 14 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6 1.850E+00 4.503E−07 −2.824E−09 −4.297E−12 7 2.562E+03 1.348E−06   4.384E−09   1.171E−11

(260) TABLE-US-00033 TABLE 33 Example 14 Free-Form Surface Data r Si Normalized Surface No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 8 1.000 —   1.274E−01   4.777E−03 — 4.783E−03 9 1.000 — −1.130E−02 −4.742E−03 — 1.945E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 8 — −6.056E-04 — −1.935E−04 9 — −6.780E-05 — −1.328E−05

(261) FIG. 52 illustrates a lens cross-section of the eyepiece according to Example 14. FIGS. 53 to 54 illustrate various aberrations of the eyepiece according to Example 14.

(262) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 14 has favorable optical performance.

Example 15

(263) Table 34 exhibits basic lens data of an eyepiece according to Example 15. In addition, Table 35 exhibits aspherical surface data. In addition, Table 36 exhibits data of polynomials representing a free-form surface.

(264) TABLE-US-00034 TABLE 34 Example 15 Lens Data Yi Zi θi Si Y- Z- Rota- Ri Ndi vdi Surface Coor- Coor- tional Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 0.124 11.000 0.000 433.316 1.963 24.1 3 0.124 16.816 0.000 −41.964 — — 4 4.150 17.813 2.804 36.431 1.877 40.8 5 3.875 23.412 2.804 125.658 — — 6 1.942 24.317 −0.944 43.233 1.661 20.4 7 2.042 30.361 −0.944 −1550.721 — — 8 4.254 32.321 −2.378 ∞ 1.553 56.0 9 4.491 38.023 −2.378 ∞ — — 10 3.837 41.909 −3.227 ∞ — —

(265) TABLE-US-00035 TABLE 35 Example 15 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6 1.850E+00 −5.838E−06 6.687E−09 −8.245E−12 7 2.562E+03 −8.251E−07 2.478E−10   3.438E−11

(266) TABLE-US-00036 TABLE 36 Example 15 Free-Form Surface Data r Si Normalized Surface No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 8 1.000 —   1.548E−01   4.670E−03 — 6.268E−03 9 1.000 — −6.431E−02 −1.923E−03 — 1.242E−02 Si Surface No. x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.2y.sup.1 8 — −1.907E−04 — −1.304E−04 9 —   3.233E−04 —   2.805E−04

(267) FIG. 55 illustrates a lens cross-section of an eyepiece according to Example 15. FIGS. 56 to 57 illustrate various aberrations of the eyepiece according to Example 15.

(268) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 15 has favorable optical performance.

Example 16

(269) Table 37 exhibits basic lens data of an eyepiece according to Example 16. In addition, Table 38 exhibits aspherical surface data. In addition, Table 39 exhibits data of polynomials representing a free-form surface.

(270) TABLE-US-00037 TABLE 37 Example 16 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 2.790 13.000 0.000 578.888 1.963 24.1 3 2.790 18.871 0.000 −42.153 — — 4 5.246 19.821 0.872 40.177 1.877 40.8 5 5.159 25.484 0.872 143.830 — — 6 2.405 26.420 −6.425 41.863 1.661 20.4 7 3.237 33.809 −6.425 −5175.045 — — 8 5.871 35.498 −5.818 ∞ 1.553 56.0 9 6.385 40.546 −5.818 ∞ — — 10 5.842 44.244 −5.784 ∞ — —

(271) TABLE-US-00038 TABLE 38 Example 16 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6 1.850E+00 −5.793E−06   8.399E−09 1.067E−13 7 2.562E+03   1.475E−06 −7.980E−10 2.903E−11

(272) TABLE-US-00039 TABLE 39 Example 16 Free-Form Surface Data r Si Normalized Surface No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 8 1.000 —   2.506E−01   9.750E−03 — 1.356E−02 9 1.000 — −5.628E−02 −9.366E−04 — 1.135E−02 Si Surface No. x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.2y.sup.1 8 — −7.832E−04 — −3.009E−04 9 —   8.495E−06 —   2.416E−04

(273) FIG. 58 illustrates a lens cross-section of the eyepiece according to Example 16. FIGS. 59 to 60 illustrate various aberrations of the eyepiece according to Example 16.

(274) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 16 has favorable optical performance.

Example 17

(275) Table 40 exhibits basic lens data of an eyepiece according to Example 17. In addition, Table 41 exhibits aspherical surface data. In addition, Table 42 exhibits data of polynomials representing a free-form surface.

(276) TABLE-US-00040 TABLE 40 Example 17 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 5.185 15.000 0.000 557.103 1.963 24.1 3 5.185 21.270 0.000 −40.615 — — 4 5.028 22.124 −5.413 43.200 1.877 40.8 5 5.584 27.997 −5.413 149.594 — — 6 3.304 29.127 −7.184 43.600 1.661 20.4 7 4.293 36.972 −7.184 −4816.589 — — 8 7.311 38.472 −3.044 ∞ 1.553 56.0 9 7.657 44.989 −3.044 ∞ — — 10 7.129 47.436 −3.274 ∞ — —

(277) TABLE-US-00041 TABLE 41 Example 17 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6 1.850E+00 −5.045E−06   7.511E−09 1.795E−12 7 2.562E+03   1.443E−06 −1.285E−09 2.200E−11

(278) TABLE-US-00042 TABLE 42 Example 17 Free-Form Surface Data r Si Normalized Surface No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 8 1.000 —   1.823E−01   1.328E−02 — 1.502E−02 9 1.000 — −6.807E−02 −7.354E−04 — 5.839E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 8 — −1.386E−03 — −1.642E−04 9 —   1.369E−04 —   2.677E−04

(279) FIG. 61 illustrates a lens cross-section of the eyepiece according to Example 17. FIGS. 62 to 63 illustrate various aberrations of the eyepiece according to Example 17.

(280) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 17 has favorable optical performance.

Example 18

(281) Table 43 exhibits basic lens data of an eyepiece according to Example 18. In addition, Table 44 exhibits aspherical surface data. In addition, Table 45 exhibits data of polynomials representing a free-form surface.

(282) TABLE-US-00043 TABLE 43 Example 18 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 4.896 11.000 0.000 281.221 1.963 24.1 3 4.896 14.803 0.000 −58.856 — — 4 4.174 15.778 −4.345 56.119 1.877 40.8 5 4.496 20.017 −4.345 428.654 — — 6 3.437 21.013 −8.382 54.419 1.661 20.4 7 4.437 27.803 −8.382 582.994 — — 8 8.779 29.095 −0.069 ∞ 1.553 56.0 9 8.791 39.060 −0.069 ∞ — — 10 6.469 41.991 −3.042 ∞ — —

(283) TABLE-US-00044 TABLE 44 Example 18 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6 −7.069E−01   1.108E−05 −7.547E−09 −5.249E−12 7   3.135E+02 −4.413E−06   3.499E−09   6.237E−13

(284) TABLE-US-00045 TABLE 45 Example 18 Free-Form Surface Data r Si Normalized Surface No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 8 1.000 —   2.326E−01   1.694E−02 — 2.289E−02 9 1.000 — −5.781E−02 −2.073E−03 — 6.542E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 8 — −1.505E−03 — −1.749E−04 9 —   8.705E−05 —   1.936E−04

(285) FIG. 64 illustrates a lens cross-section of the eyepiece according to Example 18. FIGS. 65 to 66 illustrate various aberrations of the eyepiece according to Example 18.

(286) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 18 has favorable optical performance.

Example 19

(287) Table 46 exhibits basic lens data of an eyepiece according to Example 19. In addition, Table 47 exhibits aspherical surface data. In addition, Table 48 exhibits data of polynomials representing a free-form surface.

(288) TABLE-US-00046 TABLE 46 Example 19 Lens Data Yi Zi Si Y- Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 2.824 13.000 0.000 1458.068 1.963 24.1 3 2.824 19.686 0.000 −41.251 4 3.432 20.542 −8.457 42.599 1.877 40.8 5 4.546 28.034 −8.457 1022.287 6 5.438 28.759 −7.315 47.384 1.661 20.4 7 5.993 33.083 −7.315 94.137 8 16.390 33.599 6.027 ∞ 1.553 56.0 9 15.615 40.943 6.027 ∞ 10 6.307 46.038 −3.390 ∞

(289) TABLE-US-00047 TABLE 47 Example 19 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6   2.626E−01 −3.222E−07 −2.402E−09 −4.110E−12 7 −1.311E+02   4.817E−07   1.209E−09   6.360E−12

(290) TABLE-US-00048 TABLE 48 Example 19 Free-Form Surface Data r Si Normalized Surface No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 8 1.000 —   2.144E−02   2.507E−03 — 6.629E−03 9 1.000 — −2.778E−01 −5.116E−03 — 2.479E−04 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 8 — −9.579E−04 — −2.197E−04 9 — −6.130E−06 —   1.300E−04

(291) FIG. 67 illustrates a lens cross-section of the eyepiece according to Example 19. FIGS. 68 to 69 illustrate various aberrations of the eyepiece according to Example 19.

(292) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 19 has favorable optical performance.

Example 20

(293) Table 49 exhibits basic lens data of an eyepiece according to Example 20. In addition, Table 50 exhibits aspherical surface data. In addition, Table 51 exhibits data of polynomials representing a free-form surface.

(294) TABLE-US-00049 TABLE 49 Example 20 Lens Data Si θi Ri Ndi Sur- Yi Y- Zi Z- Rota- Curva- Refrac- vdi face Coor- Coor- tional ture tive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 3.410 15.000 0.000 6044.561 1.963 24.1 3 3.410 23.219 0.000 −40.250 — — 4 2.840 24.160 −11.471 46.586 1.877 40.8 5 4.463 32.162 −11.471 423.115 — — 6 4.644 33.023 −2.076 31.090 1.661 20.4 7 4.983 42.391 −2.076 42.129 — — 8 20.477 43.948 2.522 ∞ 1.553 56.0 9 20.181 50.668 2.522 ∞ — — 10 6.431 51.705 −0.185 ∞ — —

(295) TABLE-US-00050 TABLE 50 Example 20 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6 −1.376E−01 5.512E−06 −2.299E−10 −8.308E−13 7 −1.369E+02 3.107E−07   1.663E−09   1.522E−12

(296) TABLE-US-00051 TABLE 51 Example 20 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 8 1.000 — 5.397E−02 −3.073E-03 — 9 1.000 — 1.141E−02 −2.527E-03 — Si Surface No. x.sup.0y.sup.2 x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 8 4.286E−03 — −1.122E-03 — −3.694E-05 9 7.135E−04 — −3.558E-04 — −1.284E-05

(297) FIG. 70 illustrates a lens cross-section of the eyepiece according to Example 20. FIGS. 71 to 72 illustrate various aberrations of the eyepiece according to Example 20.

(298) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 20 has favorable optical performance.

Example 21

(299) Table 52 exhibits basic lens data of an eyepiece according to Example 21. In addition, Table 53 exhibits aspherical surface data. In addition, Table 54 exhibits data of polynomials representing a free-form surface.

(300) TABLE-US-00052 TABLE 52 Example 21 Lens Data Si Yi Y- Zi Z- θi Ri Ndi vdi Surface Coor- Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 1.589 11.000 0.000 ∞ 1.963 24.1 3 1.589 15.517 0.000 −34.853 — — 4 1.584 16.467 −4.849 30.907 1.877 40.8 5 2.134 22.954 −4.849 60.290 — — 6 2.629 25.033 −1.816 52.112 1.661 20.4 7 2.884 33.081 −1.816 12228.557 — — 8 3.335 35.594 −3.883 ∞ 1.553 56.0 9 3.591 39.364 −3.883 ∞ — — 10 3.220 41.727 −4.575 ∞ — —

(301) TABLE-US-00053 TABLE 53 Example 21 Aspherical Surface Data k Si Conic Surface No. Constant A4 A6 A8 6 −4.107E+00 −3.198E−07 −3.725E−09 1.044E−13 7   3.012E+05 −4.862E−06   1.626E−09 1.324E−11

(302) TABLE-US-00054 TABLE 54 Example 21 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 8 1.000 —  1.430E−01  1.853E−03 — 9 1.000 — −7.058E−02 −5.334E−03 — Si Surface No. x.sup.0y.sup.2 x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 8 2.786E-03 — −6.715E−04 — −1.506E−04 9 2.031E-03 — −6.952E−05 —  5.811E−04

(303) FIG. 73 illustrates a lens cross-section of the eyepiece according to Example 21. FIGS. 74 to 75 illustrate various aberrations of the eyepiece according to Example 21.

(304) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 21 has favorable optical performance.

Example 22

(305) Table 55 exhibits basic lens data of an eyepiece according to Example 22. In addition, Table 56 exhibits data of polynomials representing a free-form surface.

(306) TABLE-US-00055 TABLE 55 Example 22 Lens Data Si Yi Zi θi Ri Ndi vdi Surface Y-Coor- Z-Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 1.498 11.000 0.000 134.500 1.963 24.1 3 1.498 16.309 0.000 −43.316 — — 4 1.121 17.302 −7.602 ∞ 1.553 56.0 5 1.952 23.531 −7.602 ∞ — — 6 2.738 26.111 −4.629 ∞ 1.553 56.0 7 3.248 32.409 −4.629 ∞ — — 8 3.986 34.397 −3.950 ∞ 1.553 56.0 9 4.298 38.914 −3.950 ∞ — — 10 3.637 41.093 −4.019 ∞ — —

(307) TABLE-US-00056 TABLE 56 Example 22 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 4 1.000 — −4.042E−02  1.208E−02 — 5 1.000 — −2.014E−02 −2.971E−03 — 6 1.000 —  7.422E−02  1.356E−02 — 7 1.000 — −9.236E−02 −1.514E−03 — 8 1.000 — −1.032E−01  5.241E−03 — 9 1.000 —  6.426E−02  5.089E−03 — Si Surface No. x.sup.0y.sup.2 x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 4  1.979E−02 — −1.678E−04 — −4.433E−05 5  3.780E−03 —  1.312E−05 — −5.897E−05 6  6.226E−03 —  4.724E−04 —  2.984E−05 7 −5.977E−03 — −4.038E−04 —  3.334E−04 8 −1.446E−03 — −2.939E−04 — −2.939E−04 9  1.406E−04 — −2.838E−04 — −2.838E−04

(308) FIG. 76 illustrates a lens cross-section of the eyepiece according to Example 22. FIGS. 77 to 78 illustrate various aberrations of the eyepiece according to Example 22.

(309) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 22 has favorable optical performance.

Example 23

(310) Table 57 illustrates basic lens data of an eyepiece according to Example 23. In addition, Table 58 exhibits aspherical surface data. In addition, Table 59 exhibits data of polynomials representing a free-form surface. The eyepiece according to Example 23 is configured to allow the optical axis AX (L1) of the first lens L1 to be non-parallel, instead of parallel, to the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference. In addition, a lens surface of the first lens L1 on the image side (side opposite to the eye point E.P.) is a Fresnel lens surface. In addition, a lens surface of the second lens L2 on the side of the eye point E.P. is a Fresnel lens surface. It is to be noted here that data of the Fresnel lens surface are exhibited as aspherical surface data.

(311) TABLE-US-00057 TABLE 57 Example 23 Lens Data Si Yi Zi θi Ri Ndi vdi Surface Y-Coor- Z-Coor- Rotational Curvature Refractive Abbe's No. dinate dinate Amount Radius Index Number 1 (STO) — — — ∞ — — 2 3.532 10.270 −8.234 25.886 1.535 55.6 3 4.249 15.219 −8.234 −32.792 — — 4 4.277 15.417 −8.234 47.291 1.535 55.6 5 5.168 21.571 −8.234 93.522 — — 6 8.923 24.476 −9.574 ∞ 1.535 55.6 7 9.988 30.792 −9.574 ∞ — — 8 7.746 37.273 −10.566 ∞ — —

(312) TABLE-US-00058 TABLE 58 Example 23 Aspherical Surface Data k Si Conic Surface No. Constant A3 A4 A5 2 −6.731   1.481E−04 −7.834E−06 −3.819E−07 3 −4.281 — −1.311E−05 — 4   1.819 —   2.092E−05 — 5   1.872 −1.525E−04 −3.551E−06 −8.483E−08 Si Surface No. A6 A7 A8 A9 2 −1.427E−08 −3.503E−10 −6.812E−13   6.227E−13 3 −1.787E−08 — −3.355E−11 — 4   5.356E−10 — −2.941E−12 — 5 −4.233E−10   1.145E−10   5.700E−12   1.980E−13 Si Surface No. A10 A11 A12   2   4.291E−14   1.321E−15 −5.131E−17   3   8.207E−14 — —   4 −1.872E−14 — —   5   3.836E−15 −1.107E−16 −1.682E−17

(313) TABLE-US-00059 TABLE 59 Example 23 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 — 1.479E−01 2.348E−02 — 1.495E−02 7 1.000 — 1.566E−03 1.236E−02 — 2.061E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −8.875E−04 — −5.738E−04 −3.572E−05 — 7 — −1.289E−03 — −7.640E−06 −1.012E−05 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 −1.096E−04 — 4.633E−07 — −2.517E−07 — 7 −9.719E−05 — 3.036E−05 —  2.643E−06 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 x.sup.6y.sup.0 x.sup.5y.sup.1 x.sup.4y.sup.2 6 −2.203E−06 — 1.536E−06 −5.008E-08 — 8.406E−08 7 −5.058E−06 — 6.434E−07 −1.876E-07 — 5.710E−08 Si Surface No. x.sup.3y.sup.3 x.sup.2y.sup.4 x.sup.1y.sup.5 x.sup.0y.sup.6 6 — 7.830E−09 — 2.894E−08 7 — 1.090E−09 — 8.062E−08

(314) FIG. 79 illustrates a lens cross-section of the eyepiece according to Example 23. FIGS. 80 to 81 illustrate various aberrations of the eyepiece according to Example 23.

(315) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 23 has favorable optical performance.

Example 24

(316) Table 60 exhibits basic lens data of an eyepiece according to Example 24. In addition, Table 61 exhibits aspherical surface data. In addition, Table 62 exhibits data of polynomials representing a free-form surface. The eyepiece according to Example 24 is configured to allow the optical axis AX (L1) of the first lens L1 to be non-parallel, instead of parallel, to the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference. In addition, a lens surface of the first lens L1 on the image side (side opposite to the eye point E.P.) is a Fresnel lens surface. In addition, a lens surface of the second lens L2 on the side of the eye point E.P. is a Fresnel lens surface. It is to be noted here that data of the Fresnel lens surface are exhibited as aspherical surface data.

(317) TABLE-US-00060 TABLE 60 Example 24 Lens Data Si θi Ri Ndi Sur- Yi Zi Rota- Curva- Refrac- vdi face Y-Coor- Z-Coor- tional ture tive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 5.512 11.450 −10.580 45.805 1.535 55.6 3 6.430 16.365 −10.580 −32.568 — — 4 6.467 16.562 −10.580 33.853 1.535 55.6 5 6.781 18.244 −10.580 −165.977 — — 6 8.260 20.494 −11.358 ∞ 1.535 55.6 7 9.443 26.382 −11.358 ∞ — — 8 11.736 27.950 −13.213 ∞ 1.535 55.6 9 12.955 33.141 −13.213 ∞ — — 10 11.219 40.537 −14.691 ∞ — —

(318) TABLE-US-00061 TABLE 61 Example 24 Aspherical Surface Data k Si Conic Surface No. Constant A3 A4 A5 2  −11.300   1.253E−04 −6.493E−06 −7.018E−08 3    0.179 — −3.760E−07 — 4  −0.215 —   1.040E−05 — 5 −213.619   3.656E−05   2.800E−06   6.890E−08 Si Surface No. A6 A7 A8 A9 2  −1.976E−09 −1.484E−11 −4.463E−13 −1.718E−14 3    7.928E−09 — −2.142E−11 — 4    3.388E−09 —   1.925E−12 — 5    2.004E−09 −5.067E−11 −1.799E−13   1.025E−13 Si Surface No. A10 A11 A12    2 −8.827E−16 −5.470E−17 −2.480E−18    3 −9.065E−15 — —    4 −1.200E−15 — —    5   4.129E−15   7.352E−18 −8.332E−18

(319) TABLE-US-00062 TABLE 62 Example 24 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  4.051E−02 1.051E−03 —  8.132E−04 7 1.000 — −1.804E−02 2.333E−03 — −3.040E−04 8 1.000 —  3.400E−02 7.580E−03 —  1.639E−03 9 1.000 —- −6.424E−02 7.580E−03 —  1.639E−03 Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −4.301E−05 — −1.413E−05  5.153E−07 — 7 —  4.797E−05 — −1.249E−05  7.397E−07 — 8 —  1.001E−04 — −4.812E−05 −2.219E−06 — 9 —  1.001E−04 — −4.812E−05 −2.219E−06 — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 −2.180E−06 —  9.997E−08 — −1.795E−07 — 7 −2.133E−06 — −6.975E−08 — −8.531E−08 — 8  2.364E−06 —  2.418E−07 —  7.312E−07 — 9 −1.890E−06 — −2.055E−08 — −2.145E−07 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 x.sup.6y.sup.0 x.sup.5y.sup.1 x.sup.4y.sup.2 6 −8.093E−08 —  2.733E−09 4.402E−09 — 1.616E−09 7  1.256E−08 —  1.393E−09 8.804E−09 — 1.965E−08 8  4.954E−08 — −4.832E−09 1.551E−08 — 4.886E−08 9 −1.190E−06 —  1.180E−08 6.141E−08 — 5.534E−08 Si Surface No. x.sup.3y.sup.3 x.sup.2y.sup.4 x.sup.1y.sup.5 x.sup.0y.sup.6 6 — 3.506E−09 — −1.921E−11 7 — 5.536E−09 —  1.020E−10 8 — 4.551E−09 —  1.694E−10 9 — 4.905E−08 —  7.974E−11

(320) FIG. 82 illustrates a lens cross-section of the eyepiece according to Example 24. FIGS. 83 to 84 illustrate various aberrations of the eyepiece according to Example 24.

(321) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 24 has favorable optical performance.

Example 25

(322) Tables 63 and 64 illustrate basic lens data of an eyepiece according to Example 25. Table 63 exhibits data at a visual acuity of 1.0, and Table 64 exhibits data at a visual acuity of 0.2. In addition, Table 65 exhibits aspherical surface data. In addition, Table 66 exhibits data of polynomials representing a free-form surface.

(323) FIGS. 86 and 87 each illustrate a lens cross-section of the eyepiece according to Example 25. FIG. 86 illustrates a lens cross-section at a visual acuity of 1.0, and FIG. 87 illustrates a lens cross-section at a visual acuity of 0.2.

(324) The eyepiece according to Example 25 includes the eccentric lens group G1 and the varifocal lens group G2 in order from the side of the eye point E.P. toward the image side. The eccentric lens group G1 has a configuration in which the first lens L1, the second lens L2, and the third lens L3 are arranged in order from the side of the eye point E.P. toward the image side. The varifocal lens group G2 has a configuration in which the fourth lens L4 and a fifth lens L5 are arranged in order from the side of the eye point E.P. toward the image side. The fourth lens L4 and the fifth lens L5 are each an Alvarez lens, and move mutually in directions opposite to each other and in directions different from the reference optical axis AX (E.P.), which employs the eye point E.P. as a reference, to thereby change a focal length. In addition, a lens surface of the first lens L1 on the image side (side opposite to the eye point E.P.) is a Fresnel lens surface. In addition, a lens surface of the second lens L2 on the side of the eye point E.P. is a Fresnel lens surface. It is to be noted here that data of the Fresnel lens surface are exhibited as aspherical surface data.

(325) TABLE-US-00063 TABLE 63 Example 25 Lens Data (at VISUAL ACUITY of 1.0) Si θi Ri Ndi Sur- Yi Zi Rota- Curva- Refrac- vdi face Y-Coor- Z-Coor- tional ture tive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 3.532 10.270 −8.234 25.886 1.535 55.6 3 4.249 15.219 −8.234 −32.792 — — 4 4.277 15.417 −8.234 47.291 1.535 55.6 5 5.168 21.571 −8.234 93.522 — — 6 7.803 24.638 −4.671 ∞ 1.535 55.6 7 8.325 31.022 −4.671 ∞ — — 8 3.586 34.419 −4.671 ∞ 1.535 55.6 9 3.708 35.914 −4.671 ∞ — — 10 13.691 35.299 −4.671 ∞ 1.535 55.6 11 13.813 36.794 −4.671 ∞ — — 12 8.193 39.059 −5.521 ∞ — —

(326) TABLE-US-00064 TABLE 64 Example 25 Lens Data (at VISUAL ACUITY of 0.2) Si θi Ri Ndi Sur - Yi Zi Rota- Curva- Refrac- vdi face Y-Coor- Z-Coor- tional ture tive Abbe's No. dinate dinate Amount Radius Index Number 1 — — — ∞ — — (STO) 2 3.532 10.270 −8.234 25.886 1.535 55.6 3 4.249 15.219 −8.234 −32.792 — — 4 4.277 15.417 −8.234 47.291 1.535 55.6 5 5.168 21.571 −8.234 93.522 — — 6 7.803 24.638 −4.671 ∞ 1.535 55.6 7 8.325 31.022 −4.671 ∞ — — 8 13.558 33.604 −4.671 ∞ 1.535 55.6 9 13.680 35.099 −4.671 ∞ — — 10 3.719 36.114 −4.671 ∞ 1.535 55.6 11 3.841 37.609 −4.671 ∞ — — 12 8.193 39.059 −5.521 ∞ — —

(327) TABLE-US-00065 TABLE 65 Example 25 Aspherical Surface Data k Si Conic Surface No. Constant A3 A4 A5 2 −6.731   8.131E−06   2.585E−06 −4.901E−07 3 −4.281 — −1.311E−05 — 4   1.819 —   2.092E−05 — 5   1.872 −3.676E−04   2.007E−05 −3.493E−07 Si Surface No. A6 A7 A8 A9 2 −2.285E−08 −2.995E−10   8.844E−12   7.727E−13 3 −1.787E−08 — −3.355E−11 — 4   5.356E−10 — −2.941E−12 — 5 −1.095E−08 −1.639E−10   9.240E−12   7.331E−13 Si Surface No. A10 A11 A12   2   4.191E−14   1.368E−15 −6.812E−17   3   8.207E−14 — —   4 −1.872E−14 — —   5   2.512E−14   5.250E−17 −6.437E−17

(328) TABLE-US-00066 TABLE 66 Example 25 Free-Form Surface Data Si r Surface Normalized No. Radius x.sup.1y.sup.0 x.sup.0y.sup.1 x.sup.2y.sup.0 x.sup.1y.sup.1 x.sup.0y.sup.2 6 1.000 —  1.187E−01  7.011E−03 —  7.175E−03 7 1.000 — −8.173E−02 −1.245E−02 — −4.657E−03 8 1.000 —  1.747E−02 — — — 11 1.000 —  1.747E−02 — — Si Surface No. x.sup.3y.sup.0 x.sup.2y.sup.1 x.sup.1y.sup.2 x.sup.0y.sup.3 x.sup.4y.sup.0 x.sup.3y.sup.1 6 — −1.079E−03 — −6.305E−04 −4.676E−05 — 7 —  1.714E−05 —  1.349E−04 −8.275E−07 — 8 — −5.739E−05 — −1.672E−04 — — 11 — −5.739E−05 — −1.672E−04 — — Si Surface No. x.sup.2y.sup.2 x.sup.1y.sup.3 x.sup.0y.sup.4 x.sup.5y.sup.0 x.sup.4y.sup.1 x.sup.3y.sup.2 6 −9.503E−05 — −9.184E−06 —  3.179E−06 — 7 −1.273E−05 —  2.746E−05 —  2.129E−06 — 8 — — — — −7.204E−07 — 11 — — — — −7.204E−07 — Si Surface No. x.sup.2y.sup.3 x.sup.1y.sup.4 x.sup.0y.sup.5 x.sup.6y.sup.0 x.sup.5y.sup.1 x.sup.4y.sup.2 6  5.334E−07 — 1.613E−06 2.596E−07 — 2.706E−07 7 −4.830E−06 — 7.559E−07 4.553E−07 — 8.710E−09 8  1.388E−07 — 2.302E−07 — — — 11  1.388E−07 — 2.302E−07 — — — Si Surface No. x.sup.3y.sup.3 x.sup.2y.sup.4 x.sup.1y.sup.5 x.sup.0y.sup.6 6 — 2.387E−07 — 5.132E−08 7 — 3.036E−07 — 5.935E−09 8 — — — — 11 — — — —

(329) FIGS. 88 to 91 illustrate various aberrations of the eyepiece according to Example 25. FIGS. 88 to 89 illustrate various aberrations at a visual acuity of 1.0, and FIGS. 90 to 91 illustrate various aberrations at a visual acuity of 0.2.

(330) As can be appreciated from each of the aberration diagrams, it is obvious that the eyepiece according to Example 25 has favorable optical performance.

Other Numerical Data of Respective Examples

(331) Tables 67 and 68 exhibit, in a summarized manner for respective examples, specifications of the eyepieces according to the respective examples and values of other numerical data (such as values concerning conditional expressions) satisfied by the eyepieces according to the respective examples. It is to be noted that L denotes a total length (a distance from the eye point E.P. to the image (image display device 100)). As can be appreciated from Tables 67 and 68, desired configurations are satisfied for the respective examples. As exhibited in Tables 67 and 68, the image magnification My of each of the examples is twice or more. In addition, in each of the examples, a refractive index of the first lens L1 with respect to the d-line is 1.439 or more. In addition, in each of the examples, relationships of the conditional expressions (1) and (2) concerning the eccentric amount si,max and the rotational amount θi,max are satisfied.

(332) TABLE-US-00067 TABLE 67 Example Example Example Example Example Example 1 2 3 4 5 6 Lens 3-Group 3-Group 3-Group 3-Group 3-Group 3-Group Configuration 3-Lens 3-Lens 3-Lens 3-Lens 3-Lens 3-Lens L [mm] 44.133 46.98 46.421 43.683 43.728 48.477 Mv 2.747 2.911 2.879 2.845 2.848 3.133 Refractive 1.439 1.963 1.963 1.963 1.963 1.963 Index of L1 Shape of L1 Convex Convex Convex Convex Convex Convex on E.P. Side Relationship Parallel Parallel Parallel Parallel Parallel Parallel between L1 and Virtual Image Plane si,max [mm] 5.336 9.610 7.064 10.305 7.796 8.108 θi,max 16.931 21.124 20.433 22.975 24.657 15.548 [degree] Example Example Example Example Example Example 7 8 9 10 11 23 Lens 3-Group 3-Group 3-Group 3-Group 3-Group 3-Group Configuration 3-Lens 3-Lens 3-Lens 3-Lens 3-Lens 3-Lens L [mm] 41.528 45.036 47.901 44.822 43.297 37.273 Mv 2.835 3.054 3.233 3.040 2.945 2.357 Refractive 1.963 1.963 1.963 1.883 1.883 1.535 Index of L1 Shape of L1 Convex Convex Convex Flat Convex Convex on E.P. Side Relationship Parallel Parallel Parallel Parallel Parallel Non- between L1 Parallel and Virtual Image Plane si,max [mm] 8.164 8.727 9.190 4.968 5.430 9.988 θi,max 22.859 16.363 9.970 13.673 5.411 10.566 [degree]

(333) TABLE-US-00068 TABLE 68 Example Example Example Example Example 12 13 14 15 16 Lens 4-Group 4-Group 4-Group 4-Group 4-Group Configuration 4-Lens 4-Lens 4-Lens 4-Lens 4-Lens L [mm] 45.982 46.374 48.077 41.909 44.244 Mv 2.853 2.876 2.974 2.739 2.879 Refractive 1.439 1.963 1.963 1.963 1.963 Index of L1 Shape of L1 Convex Convex Convex Convex Convex on E.P. Side Relationship Parallel Parallel Parallel Parallel Parallel between L1 and Virtual Image Plane si,max [mm] 4.009 3.496 6.499 4.491 6.385 θi,max 6.359 4.315 7.004 3.227 6.425 [degree] Example Example Example Example 17 18 19 20 Lens 4-Group 4-Group 4-Group 4-Group Configuration 4-Lens 4-Lens 4-Lens 4-Lens L [mm] 47.436 41.991 46.038 51.705 Mv 3.071 2.863 3.116 3.473 Refractive 1.963 1.963 1.963 1.963 Index of L1 Shape of L1 Convex Convex Convex Convex on E.P. Side Relationship Parallel Parallel Parallel Parallel between L1 and Virtual Image Plane si,max [mm] 7.657 8.791 16.390 20.477 θi,max 7.184 8.382 8.457 11.471 [degree] Example Example Example Example 21 22 24 25 Lens 4-Group 4-Group 4-Group 5-Group Configuration 4-Lens 4-Lens 4-Lens 5-Lens L [mm] 41.727 41.093 40.537 39.059 Mv 2.847 2.808 2.532 2.458 Refractive 1.963 1.963 1.535 1.535 Index of L1 Shape of L1 Flat Convex Convex Convex on E.P. Side Relationship Parallel Parallel Non- Non- between L1 Parallel Parallel and Virtual Image Plane si,max [mm] 3.591 4.298 12.955 13.813 θi,max 4.849 7.602 14.691 8.234 [degree]

5. Other Embodiments

(334) The technique according to the present disclosure is not limited to the description of the foregoing embodiments and examples, and may be modified and worked in a wide variety of ways.

(335) For example, shapes and numerical values of the respective parts illustrated in each of the above numerical examples are each a mere example of implementation of the present technology, and the technical scope of the present technology should not be construed as being limited by these examples.

(336) In addition, although the description has been given, in the foregoing embodiments and examples, of the configuration substantially including three or four lenses, a configuration may be employed that further includes a lens having no substantial refractive power.

(337) In addition, a surface forming an aspherical surface or a free-form surface is not limited to the lens surfaces exhibited in the respective examples; a surface other than the lens surfaces exhibited in the respective examples may be an aspherical surface or a free-form surface.

(338) In addition, for example, the present technology may have the following configurations.

(339) According to the present technology having the following configurations, the configuration of the lenses is optimized that configure the left eyepiece optical system and the right eyepiece optical system, and the non-overlap image region is included in the left-eye display image and the right-eye display image. This makes it possible to achieve a lighter weight and a wider angle of view upon observation by both eyes without causing a concern about generation of stray light and to provide high-definition beauty of an image.

(340) [1]

(341) A display apparatus including:

(342) a left eyepiece display unit including a left-eye image display device and a left eyepiece optical system that guides a left-eye display image displayed on the left-eye image display device to a left eye; and

(343) a right eyepiece display unit including a right-eye image display device and a right eyepiece optical system that guides a right-eye display image displayed on the right-eye image display device to a right eye,

(344) an image magnification upon observation by both eyes being twice or more,

(345) the left eyepiece optical system and the right eyepiece optical system each including a plurality of single lenses,

(346) at least one of the plurality of single lenses including a free-form surface lens including a resin material,

(347) at least one of the plurality of single lenses being arranged in at least one of an eccentric state or a rotated state with respect to an optical axis of the left-eye image display device or the right-eye image display device, and

(348) the left-eye display image and the right-eye display image each including an overlap image region and a non-overlap image region, the overlap image region including a mutually common image part, the non-overlap image region including a mutually different image part and being a region outside the overlap image region.

(349) [2]

(350) The display apparatus according to [1], in which the left eyepiece optical system and the right eyepiece optical system each include an eyepiece of a three-group three-lens configuration in which a first lens, a second lens, and a third lens are arranged as the plurality of single lenses in order from side of an eye point toward image side.

(351) [3]

(352) The display apparatus according to [2], in which

(353) the first lens includes a spherical lens having a positive refractive power including a material of a refractive index of 1.439 or more with respect to a d-line, and

(354) a lens surface of the first lens on the side of the eye point has a convex shape or a planar shape.

(355) [4]

(356) The display apparatus according to [2] or [3], in which an optical axis of the first lens is parallel to a reference optical axis which employs the eye point as a reference.

(357) [5]

(358) The display apparatus according to any one of [2] to [4], in which at least one of the second lens or the third lens includes a free-form surface lens.

(359) [6]

(360) The display apparatus according to any one of [2] to [5], in which

(361) at least one of the first lens, the second lens, or the third lens is arranged in at least one of the eccentric state or the rotated state with respect to the reference optical axis which employs the eye point as a reference, and

(362) the following expressions:
si,max<25 (mm)  (1)
θi,max<25(°)  (2)
are satisfied, where

(363) si,max denotes a maximum absolute value of an eccentric amount of each of respective optical axes of the first lens, the second lens, and the third lens with respect to the reference optical axis in a direction orthogonal to the reference optical axis, and

(364) θi,max denotes a maximum absolute value of a rotational amount of each of the respective optical axes of the first lens, the second lens, and the third lens with respect to the reference optical axis.

(365) [7]

(366) The display apparatus according to any one of [2], [5], and [6], in which the optical axis of the first lens is non-parallel to the reference optical axis which employs the eye point as a reference.

(367) [8]

(368) The display apparatus according to any one of [2] and [5] to [7], in which the first lens includes a Fresnel lens.

(369) [9]

(370) The display apparatus according to [1], in which the left eyepiece optical system and the right eyepiece optical system each include an eyepiece of a four-group four-lens configuration in which a first lens, a second lens, a third lens, and a fourth lens are arranged as the plurality of single lenses in order from side of an eye point toward image side.

(371) [10]

(372) The display apparatus according to [9], in which

(373) the first lens includes a spherical lens having a positive refractive power including a material of a refractive index of 1.439 or more with respect to a d-line, and

(374) a lens surface of the first lens on the side of the eye point has a convex shape or a planar shape.

(375) [11]

(376) The display apparatus according to [9] or [10], in which an optical axis of the first lens is parallel to a reference optical axis which employs the eye point as a reference.

(377) [12]

(378) The display apparatus according to any one of [9] to [11], in which at least one of the second lens, the third lens, or the fourth lens includes a free-form surface lens.

(379) [13]

(380) The display apparatus according to any one of [9] to [12], in which

(381) at least one of the first lens, the second lens, the third lens, or the fourth lens is arranged in at least one of the eccentric state or the rotated state with respect to the reference optical axis which employs the eye point as a reference, and

(382) the following expressions:
si,max<25 (mm)  (1)
θi,max<25(°)  (2)
are satisfied, where

(383) si,max denotes a maximum absolute value of an eccentric amount of each of respective optical axes of the first lens, the second lens, the third lens, and the fourth lens with respect to the reference optical axis in a direction orthogonal to the reference optical axis, and

(384) θi,max denotes a maximum absolute value of a rotational amount of each of the respective optical axes of the first lens, the second lens, the third lens, and the fourth lens with respect to the reference optical axis.

(385) [14]

(386) The display apparatus according to any one of [9], [12], and [13], in which the optical axis of the first lens is non-parallel to the reference optical axis which employs the eye point as a reference.

(387) [15]

(388) The display apparatus according to any one of [9] and [12] to [14], in which the first lens includes a Fresnel lens.

(389) [16]

(390) The display apparatus according to [1], in which, in each of the left eyepiece optical system and the right eyepiece optical system, the plurality of single lenses includes a varifocal lens group.

(391) [17]

(392) The display apparatus according to [16], in which, in each of the left eyepiece optical system and the right eyepiece optical system, the plurality of single lenses includes an eccentric lens group and the varifocal lens group in order from side of an eye point toward image side.

(393) [18]

(394) The display apparatus according to any one of [1] to [17], in which

(395) the non-overlap image region is a region on outer left side of the overlap image region in the left-eye display image, and

(396) the non-overlap image region is a region on outer right side of the overlap image region in the right-eye display image.

(397) This application claims the benefits of Japanese priority Patent Application JP2018-143854 filed with the Japan Patent Office on Jul. 31, 2018, and Japanese priority Patent Application JP2019-032308 filed with the Japan Patent Office on Feb. 26, 2019, the entire contents of which are incorporated herein by reference.

(398) It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.