Electronic image pickup system

Abstract

The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-banding zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Claims

1. An image pickup apparatus, comprising: a zoom lens, and an image pickup device located on an image side thereof, wherein: said zoom lens comprises a fixed lens group that includes a lens and a reflecting element, and remains fixed in position upon zooming from a wide-angle end to a telephoto end thereof, and at least two moving lens groups that are located on an image side with respect to said fixed lens group and move upon zooming from the wide-angle end to the telephoto end, and wherein: said reflecting element reflects a light ray after it enters a refractive entrance surface of said zoom lens, said zoom lens includes one reflecting element in all, said image pickup element is positioned on a side of a path taken by light reflected off said reflecting element, a most-object-side moving lens group of said at least two moving lens groups is a positive-refracting-power moving lens group, and said reflecting element is a prism having a refractive entrance surface and a refractive exit surface.

2. The image pickup apparatus according to claim 1, wherein said positive-refracting-power moving lens group includes three lenses, and a most-object-side lens in said positive-refracting-power moving lens group is a positive lens.

3. The image pickup apparatus according to claim 1, wherein said positive-refracting-power moving lens group includes five lenses.

4. The image pickup apparatus according to claim 1, wherein said positive-refracting-power moving lens group includes a cemented lens component.

5. An image pickup apparatus, comprising: a zoom lens, and an image pickup device located on an image side thereof, wherein: said zoom lens comprises a fixed lens group that includes a lens and a reflecting element, and remains fixed in position upon zooming from a wide-angle end to a telephoto end thereof, and at least two moving lens groups that are located on an image side with respect to said fixed lens group and move upon zooming from the wide-angle end to the telephoto end, and wherein: said reflecting element reflects a light ray after it enters a refractive entrance surface of said zoom lens, said zoom lens includes one reflecting element in all, said image pickup element is positioned on a side of a path taken by light reflected off said reflecting element, a most-object-side moving lens group of said at least two moving lens groups is a positive-refracting-power moving lens group, and said positive-refracting-power moving lens group includes five lenses.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIGS. 1(a) to 1(c) are sections in schematic illustrative of Example 1 of the optical path-bending zoom optical system used with the electronic image pickup system of the invention at the telephoto end (a), intermediate state (b) and wide-angle end (c) when the optical path-bending zoom optical system is focused on an object point at infinity.

(2) FIGS. 2(a) to 2(c) are sections in schematic illustrative of Example 2 of the optical path bending-zoom optical system, similar to FIGS. 1(a) to 1(c).

(3) FIGS. 3(a) to 3(c) are sections in schematic illustrative of Example 3 of the optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(4) FIGS. 4(a) to 4(c) are sections in schematic illustrative of Example 4 of the optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(5) FIGS. 5(a) to 5(c) are sections in schematic illustrative of Example 5 of the optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(6) FIGS. 6(a) to 6(c) are sections in schematic illustrative of Example 6 of the optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(7) FIGS. 7(a) to 7(c) are sections in schematic illustrative of Example 7 of the Optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(8) FIGS. 8(a) to 8(c) are sections in schematic illustrative of Example 8 of the optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(9) FIGS. 9(a) to 9(c) are sections in schematic illustrative of Example 9 of the optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(10) FIGS. 10(a) to 10(c) are sections in schematic illustrative of Example 10 of the optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(11) FIGS. 11(a) to 11(c) are sections in schematic illustrative of Example 11 of the optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(12) FIGS. 12(a) to 12(c) are sections in schematic illustrative of Example 12 of the optical path-bending zoom optical system, similar to FIGS. 1(a) to 1(c).

(13) FIGS. 13(a) to 13(c) are aberration diagrams of Example 1 upon focused on an object point at infinity.

(14) FIGS. 14(a) to 14(c) are aberration diagrams of Example 12 upon focused on an object point at infinity.

(15) FIGS. 15(a) and 15(b) are conceptual schematics illustrative of one embodiment of how to receive the optical path bending-zoom optical system of the invention in place.

(16) FIG. 16 is a conceptual schematic illustrative of one embodiment of how to receive the optical system body in place when the reflecting optical element for bending an optical path is constructed of a mirror.

(17) FIG. 17 is a conceptual schematic illustrative of another embodiment of how to receive the optical system in place when the reflecting optical element for bending an optical path is constructed of a mirror.

(18) FIGS. 18(a) and 18(b) are conceptual schematics illustrative of one embodiment of how to receive the optical system in place when the reflecting optical element for bending an optical path is constructed of a liquid or transformable prism.

(19) FIG. 19 is a conceptual schematic illustrative of how to carry out focusing when the reflecting optical element for bending an optical path is constructed of a variable-shape mirror.

(20) FIG. 20 is a conceptual schematic illustrative of the surface shape of a variable-shape mirror.

(21) FIG. 21 is a conceptual schematic illustrative of how to correct camera movements when the reflecting optical element for bending an optical path is constructed of a variable-shape mirror,

(22) FIG. 22 is a conceptual schematic illustrative of how to split a finder optical path from the optical path-bending zoom optical system,

(23) FIG. 23 is a diagram indicative of the transmittance characteristics of one example of the near-infrared sharp cut coat.

(24) FIG. 24 is a diagram indicative of the transmittance characteristics of one example of the color filter located on the exit surface side of the low-pass filter.

(25) FIG. 25 is a schematic illustrative of how the color filter elements are arranged in the complementary mosaic filter.

(26) FIG. 26 is a diagram indicative of one example of the wavelength characteristics of the complementary mosaic filter.

(27) FIG. 27 is a detailed perspective view illustrative of one example of the aperture stop portion in each example.

(28) FIGS. 28 (a) and 28(b) are illustrative in detail of another example of the aperture stop in each example.

(29) FIG. 29 is a front perspective schematic illustrative of the outside shape of & digital camera with the inventive optical path-bending zoom optical system built therein.

(30) FIG. 30 is a rear perspective schematic of the digital camera of FIG. 29.

(31) FIG. 31 is a sectional schematic of the digital camera of FIG. 29.

(32) FIG. 32 is a front perspective view of an uncovered personal computer in which the inventive optical path-bending zoom optical system is built in the form of an objective optical system.

(33) FIG. 33 is a sectional schematic of a phototaking optical system for a personal computer.

(34) FIG. 34 is a side view of FIG. 32.

(35) FIGS. 35(a) to 35(c) are a front and a side view of a cellular phone with the inventive optical path-bending zoom optical system built in as an objective optical system, and a sectional view of a phototaking optical system therefore, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(36) Examples 1 to 12 of the optical path-bending zoom optical system used with the electronic image pickup system of the invention are now explained. Sectional lens configurations of these examples at the telephoto end (a), intermediate state (b) and wide-angle end (c) upon focused on an object point at infinity are shown in FIGS. 1 through 12 wherein G1 represents a first lens group, G1-1 a 1-1st lens group, G1-2 a 1-2nd lens group, G2 a second lens group, G3 a third lens group, G4 a fourth lens group, G5 a fifth lens group, P an optical path-bending prism, S an aperture stop (in an independent case), IF a near infrared cut filter, IC a near infrared cut coat surface, LF a low-pass filter, CG a cover glass for an electronic image pickup device CCD, and I the image plane of CCD. The near infrared cut filter IF and low-pass filter LF or the near infrared cut coat surface IC, low-pass filter LF and cover glass CG, located in order from the object side of the zoom optical system, are fixedly provided between the final lens group and the image plane I.

(37) As shown in FIG. 1, Example 1 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group G1-1 consisting of an optical path-bending prism P equivalent to a double-concave negative lens, a 1-2nd lens group G1-2 consisting of a double-convex positive lens, a second lens group G1 consisting of an aperture stop and a double-convex positive lens, a third lens group G3 consisting of a doublet composed of a double-convex positive lens and a double-concave negative lens and a double-convex positive lens, a fourth lens group G4 consisting of a negative meniscus lens convex on its object side, and a fifth lens group G5 consisting of a double-convex positive lens. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side while the spacing between them becomes wide and then narrow, and the fourth lens group G4 and the third lens group G3 move toward the object side while the spacing between them becomes wide.

(38) Four aspheric surfaces are used, one at the object-side surface of the double-convex positive lens in the 1-2nd lens group G1-2, one at the object-side surface of the double-convex positive lens in the second lens group G2, one at the image-side surface of the negative meniscus lens in the fourth lens group G4, and one at the image-side surface of the double-convex positive lens in the fifth lens group G5.

(39) As shown in FIG. 2, Example 2 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group consisting of an optical path bending-prism P equivalent to a double-concave negative-lens, a 1-2nd lens group consisting of a double-convex positive lens, an independently moving aperture stop S, a second lens group G2 consisting of a double-convex positive lens, a positive meniscus lens convex on its object side and a negative meniscus lens convex on its object side, a third lens group G3 consisting of a double-convex positive lens and a negative meniscus lens convex on its image side, and a fourth lens group G4 consisting of a positive meniscus lens convex on its object side. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group move toward the object side while the spacing between them becomes wide. The aperture stop S located between the 1-2nd lens group 1-2 and the second lens group G2, too, moves toward the object side while the spacing between the 1-2nd lens group G1-2 and the fourth lens group G4 becomes narrow.

(40) Three aspheric surfaces are used, one at the object-side surface of the double-convex positive lens in the 1-2nd lens group G1-2, one at the surface of the second lens group G2 located nearest to its object side, and one at the object-side surface of the positive meniscus lens in the fourth lens group G4.

(41) As shown in FIG. 3, Example 3 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group G1-1 consisting of a negative meniscus lens convex on its object side and an optical path bending prism P equivalent to a plane-parallel plate, a 1-2nd lens group G1-2 consisting of a double-concave negative lens and a double-convex positive lens, a second lens group G2 consisting of an aperture stop and a double-convex positive lens, a third lens group G3 consisting of a double-convex positive lens, a negative meniscus lens convex on its object side, a double-convex positive lens and a negative meniscus lens convex on its image side, and a fourth lens group G4 consisting of a positive meniscus lens convex on its image side. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side of the zoom optical system while the spacing between them becomes wide and then narrow.

(42) Three aspheric surface are used, one at the object side-surface of the double-convex positive lens in the 1-2nd group G1-2, one at the surface of the third lens group G3 located nearest to its object side, and one at the object side-surface of the positive meniscus lens in the fourth lens group G4.

(43) As shown in FIG. 4, Example 4 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group G1-1 consisting of a negative meniscus lens convex on its object side and an optical path bending prism P equivalent to a plane-parallel plate, a 1-2nd lens group G1-2 consisting of a double-concave negative lens and a double-convex positive lens, a second lens group G2 consisting of an aperture stop, a double-convex positive lens, a double-convex positive lens and a negative meniscus lens convex on its object side, a third lens group G3 consisting of a positive meniscus lens convex on its object side, and a fourth lens group G4 consisting of a positive meniscus lens convex on its image side. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side of the zoom optical system while the spacing between them becomes wide and then narrow.

(44) Three aspheric surfaces are used, one at the object-side surface of the double-convex positive lens in the 1-2nd lens group G1-2, one at the object-side surface of the double-convex positive lens located after the stop in the second lens group G2, and one at the object-side surface of the positive meniscus lens in the second lens group G4.

(45) As shown in FIG. 5, Example 5 is directed to an optical path-bending zoom optical system made up of a first lens group G1 consisting of a positive meniscus lens convex on its object side, a negative meniscus lens convex on its object side and an optical path bending prism P equivalent to a plane-parallel plate, a second lens group G2 consisting of an aperture stop and a double-convex positive lens, a third lens group G3 consisting of a doublet consisting of a double-convex positive lens and a double-concave negative lens and a double-convex positive lens, a fourth lens group G4 consisting of a negative meniscus lens convex on its object side, and a fifth lens group G5 consisting of a positive meniscus lens convex on its object side. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side of the zoom optical system while the spacing between them becomes wide and then narrow, the third lens group G3 and the fourth lens group G4 move toward the object side while the spacing between them becomes wide, and the fifth lens group moves slightly toward the image side of the zoom optical system.

(46) Four aspheric surfaces are used, one at the image-side surface of the double-convex positive lens in the first lens group G1, one at the object side-surface of the double-convex positive lens in the second lens group G2, one at the image side-surface of the negative meniscus lens in the fourth lens group G4 and one at the image side-surface of the positive meniscus lens in the fifth lens group G5.

(47) As shown in FIG. 6, Example 6 is directed to an optical path-bending zoom optical system made up of a first lens group G1 consisting of a double-convex positive lens, a double-concave negative lens and an optical path bending prism P equivalent to a plane-parallel plate, a second lens group G2 consisting of an aperture stop and a doublet consisting of a double-convex positive lens and a negative meniscus lens convex on its image side, a third lens group G3 consisting of a negative meniscus lens convex on its object side, and a fourth lens group G4 consisting of a double-convex positive lens. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group 92 and the third lens group G3 move toward the object side of the zoom optical system while the spacing between them becomes wide, and the fourth lens group G4 moves slightly toward the object side on the telephoto side while it moves in a convex orbit toward the image side of the zoom lens optical system.

(48) Three aspheric surfaces are used, one at the object side-surface of the double-concave negative lens in the first lens group G1, one at the surface of the second lens group G2 located nearest to its object side and one at the image side-surface of the negative meniscus lens in the third lens group G3.

(49) As shown in FIG. 7, Example 7 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group G1-1 consisting of a negative meniscus lens convex on its object side and an optical path bending prism F equivalent to a plane-parallel plate, a 1-2nd lens group G1-2 consisting of a double-concave positive lens and a double-convex positive lens, a second lens group G2 consisting of an aperture stop, a double-convex positive lens, a doublet composed of a double-convex positive lens and a negative meniscus lens convex on its image side, a third lens group G3 consisting of a positive meniscus lens convex on its image side, and a fourth lens group G4 consisting of a positive meniscus lens convex on its image side. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side of the zoom optical system while the spacing between them becomes wide and then narrow.

(50) Three aspheric surfaces are used, one at the image side-surface of the negative meniscus lens in the 1-1st lens group G1-1, one at the surface of the second lens group G2 located nearest to the object side and one at the object side-surface of the positive meniscus lens in the fourth lens group G4.

(51) As shown in FIG. 8, Example 8 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group G1-1 consisting of a negative meniscus lens convex on its object side and an optical path bending prism P equivalent to a plane-parallel plate, a 1-2nd lens group G1-2 consisting of a double-concave negative lens and a positive meniscus lens convex on its object side, a second lens group G2 consisting of an aperture stop, a double-convex positive lens and a doublet composed of a double-convex positive lens and a double-concave negative lens, a third lens group G3 consisting of a positive meniscus lens convex on its image side, and a fourth lens group G4 consisting of a positive meniscus lens convex on its image side. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side of the zoom optical system while the spacing between them becomes wide and then narrow.

(52) Three aspheric surfaces are used, one at the object side-surface of the negative meniscus lens in the 1-1st lets group G1-1, the surface of the second lens group G2 located nearest to its object side and one at the image side-surface of the positive meniscus lens in the fourth lens group G4.

(53) As shown in FIG. 9, Example 9 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group G1-1 consisting of a negative meniscus lens convex on its object side and an optical path bending prism P equivalent to a plane-parallel plate, a 1-2nd lens group G1-2 consisting of a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, a second lens group G2 consisting of an aperture stop and a double-convex positive lens, a third lens group G3 consisting of a double-convex positive lens, a negative meniscus lens convex on its object side and a doublet composed of a double-convex positive lens and a double-concave negative lens, and a fourth lens group G9 consisting of a positive meniscus lens convex on its image side. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side while the spacing between them becomes wide and then narrow.

(54) Three aspheric surfaces are used, one at the image side-surface of the negative meniscus lens in the 1-2nd lens group G1-2, one at the surface of the third lens group G3 located nearest to its object side and one at the object side-surface of the positive meniscus lens in the fourth lens group G4.

(55) As shown in FIG. 10, Example 10 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group G1-1 consisting of a negative meniscus lens convex on its object side and an optical path bending prism P equivalent to a plane-parallel plate, a 1-2nd lens group G1-2 consisting: of a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, a second lens group G2 consisting of an aperture stop and a doublet composed of a double-convex positive lens and a negative meniscus lens convex on its image plane side, a third lens group G3 consisting of a positive meniscus lens convex on its object side, a negative meniscus lens convex on its object side and a doublet composed of a double-convex positive lens- and a double-concave negative lens, and a fourth lens group G4 consisting of a positive meniscus lens convex on its image plane side. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side of the zoom lens system while the spacing between them becomes wide and then narrow.

(56) Three aspheric surfaces are used, one at the image plane side-surface of the negative meniscus lens in the 1-2nd lens group G1-2, one at the surface of the third lens group G3 located nearest to its object side and one at the object side-surface of the positive meniscus lens in the fourth lens group G4.

(57) As shown in FIG. 11, Example 11 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group G1-1 consisting of a negative meniscus lens convex on its object side and an optical path bending prism P equivalent to a plane-parallel plate, a 1-2nd lens group consisting of a negative meniscus lens convex on its object side and a positive meniscus lens convex on its object side, a second lens group G2 consisting of an aperture stop and a doublet composed of a double-convex positive lens and a negative meniscus lens convex on its image plane side, a third lens group G3 consisting of a positive meniscus lens convex on its object side and a doublet composed of a planoconvex positive lens and a planoconcave negative lens, and a fourth lens group G4 consisting of a double-convex positive lens. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side of the zoom optical system while the spacing between them becomes wide and then narrow.

(58) Three aspheric surfaces are used, one at the image plane side-surface of the negative meniscus lens in the 1-2nd lens group G1-2, one at the object side-surface of the positive meniscus lens in the third lens group G3 and one at the image plane side-surface of the double-convex positive lens in the fourth lens group G4.

(59) As shown in FIG. 12, Example 12 is directed to an optical path-bending zoom optical system made up of a 1-1st lens group G1-1 consisting of an optical path bending prism P equivalent to a planoconcave negative lens, a 1-2nd lens group G1-2 consisting of a doublet composed of a negative meniscus lens concave on its object side and a positive meniscus lens concave on its object side, a second lens group G2 consisting of a positive meniscus lens convex on its object side and a negative meniscus lens convex on its object side, a third lens group G3 consisting of a double-convex positive lens, and a fourth lens group G4 consisting of a positive meniscus lens convex on its image plane side. For zooming from the wide-angle end to the telephoto end of the zoom optical system, the second lens group G2 and the third lens group G3 move toward the object side of the zoom optical system while the spacing between them becomes wide and then narrow.

(60) Three aspheric surfaces are used, one at the object side-surface of the optical path bending prism P in the 1-1st lens group G1-1, one at the surface of the second lens group G2 located nearest to its object side and one at the image plane side-surface of the positive meniscus lens in the fourth lens group G4.

(61) Set out below are the numerical data on each example. Symbols used hereinafter but not hereinbefore have the following meanings: f: focal length of the zoom optical system 2: field angle F.sub.NO: F-number WE: wide-angle end ST: standard or intermediate state TE: telephoto end r.sub.1, r.sub.2, . . . : radius of curvature of each lens element d.sub.1, d.sub.2, . . . : spacing between the adjacent lens elements n.sub.d1, n.sub.d2, . . . : d-line refractive index of each lens element v.sub.d1, v.sub.d2, . . . : Abbe constant of each lens element

(62) Here let x be an optical axis on condition that the direction of propagation of light is positive and y be a direction perpendicular to the optical axis. Then, aspheric configuration is given by
x=(y.sup.2/r)/[1+{1(K+1)(y/r).sup.2}.sup.1/2]+A.sub.4y.sup.4+A.sub.6y.sup.6+A.sub.8y.sup.8+A.sub.10y.sup.10
where r is a paraxial radius of curvature, K is a conical coefficient, and A.sub.4, A.sub.6, A.sub.8 and A.sub.10 are the fourth, sixth, eighth and tenth aspheric coefficients, respectively.

Example 1

(63) TABLE-US-00001 r.sub.1 = 26.8147 d.sub.1 = 3.8000 n.sub.d1 = 1.73400 .sub.d1 = 51.47 r.sub.2 = (Mirror) d.sub.2 = 3.2000 n.sub.d2 = 1.73400 .sub.d2 = 51.47 r.sub.3 = 6.2254 d.sub.3 = 1.7202 r.sub.4 = 424.9864 (Aspheric) d.sub.4 = 2.4297 n.sub.d3 = 1.84666 .sub.d3 = 23.78 r.sub.5 = 48.1247 d.sub.5 = (Variable) r.sub.6 = (Stop) d.sub.6 = 0.5000 r.sub.7 = 17.8731 (Aspheric) d.sub.7 = 2.0000 n.sub.d4 = 1.58913 .sub.d4 = 61.26 r.sub.8 = 16.6911 d.sub.8 = (Variable) r.sub.9 = 7.9903 d.sub.9 = 6.2379 n.sub.d5 = 1.48749 .sub.d5 = 70.23 r.sub.10 = 14.7007 d.sub.10 = 0.8488 n.sub.d6 = 1.84666 .sub.d6 = 23.78 r.sub.11 = 7.0178 d.sub.11 = 1.1903 r.sub.12 = 11.2307 d.sub.12 = 1.6307 n.sub.d7 = 1.84666 .sub.d7 = 23.78 r.sub.13 = 24.5400 d.sub.13 = (Variable) r.sub.14 = 18.1763 d.sub.14 = 0.5000 n.sub.d8 = 1.84666 .sub.d8 = 23.78 r.sub.15 = 5.9110 (Aspheric) d.sub.15 = (Variable) r.sub.16 = 14.1876 d.sub.16 = 3.0000 n.sub.d9 = 1.58913 .sub.d9 = 61.26 r.sub.17 = 7.1178 (Aspheric) d.sub.17 = 0.5006 r.sub.18 = d.sub.18 = 0.8000 n.sub.d10 = 1.51633 .sub.d10 = 64.14 r.sub.19 = d.sub.19 = 1.8000 n.sub.d11 = 1.54771 .sub.d11 = 62.84 r.sub.20 = d.sub.20 = 0.5000 r.sub.21 = d.sub.21 = 0.5000 n.sub.d12 = 1.51633 .sub.d12 = 64.14 r.sub.22 = d.sub.22 = 1.1914 r.sub.23 = (Image Plane) Aspherical Coefficients 4th surface K = 0.0195 A.sub.4 = 5.4111 10.sup.4 A.sub.6 = 2.1984 10.sup.6 A.sub.8 = 4.5957 10.sup.7 A.sub.10 = 1.0754 10.sup.8 7th surface K = 5.8821 A.sub.4 = 2.7575 10.sup.4 A.sub.6 = 5.8194 10.sup.6 A.sub.8 = 7.9649 10.sup.7 A.sub.10 = 3.4848 10.sup.8 15th surface K = 3.6043 A.sub.4 = 2.6150 10.sup.3 A.sub.6 = 8.5623 10.sup.6 A.sub.8 = 2.8972 10.sup.6 A.sub.10 = 1.5174 10.sup.7 17th surface K = 0.8882 A.sub.4 = 1.1140 10.sup.3 A.sub.6 = 8.5962 10.sup.6 A.sub.8 = 3.9677 10.sup.7 A.sub.10 = 3.1086 10.sup.8 Zooming Data () WE ST TE f (mm) 4.59000 8.95000 13.23000 FNO 2.8316 3.8724 4.6438 2 () 65.5 34.0 23.0 d.sub.5 12.93741 5.34873 2.00000 d.sub.8 2.61607 2.85689 0.50000 d.sub.13 1.09671 5.22639 10.38165 d.sub.15 1.00016 4.21405 4.71724

Example 2

(64) TABLE-US-00002 r.sub.1 = 129.7294 d.sub.1 = 4.5500 n.sub.d1 = 1.80400 .sub.d1 = 46.57 r.sub.2 = (Mirror) d.sub.2 = 4.0019 n.sub.d2 = 1.80400 .sub.d2 = 46.57 r.sub.3 = 5.3898 d.sub.3 = 1.6465 r.sub.4 = 30.0332 (Aspheric) d.sub.4 = 1.4609 n.sub.d3 = 1.84666 .sub.d3 = 23.78 r.sub.5 = 35.8611 d.sub.5 = (Variable) r.sub.6 = (Stop) d.sub.6 = (Variable) r.sub.7 = 9.6063 (Aspheric) d.sub.7 = 2.7296 n.sub.d4 = 1.48749 .sub.d4 = 70.23 r.sub.8 = 30.8421 d.sub.8 = 0.1469 r.sub.9 = 10.1172 d.sub.9 = 2.1277 n.sub.d5 = 1.69680 .sub.d5 = 55.53 r.sub.10 = 97.1974 d.sub.10 = 0.0500 r.sub.11 = 12.1982 d.sub.11 = 0.7949 n.sub.d6 = 1.84666 .sub.d6 = 23.78 r.sub.12 = 5.7271 d.sub.12 = (Variable) r.sub.13 = 14.2960 d.sub.13 = 4.0342 n.sub.d7 = 1.48749 .sub.d7 = 70.23 r.sub.14 = 15.7323 d.sub.14 = 0.1401 r.sub.15 = 18.5671 d.sub.15 = 1.1241 n.sub.d8 = 1.84666 .sub.d8 = 23.78 r.sub.16 = 29.8834 d.sub.16 = (Variable) r.sub.17 = 46.3841 (Aspheric) d.sub.17 = 1.1752 n.sub.d9 = 1.58913 .sub.d9 = 61.26 r.sub.18 = 541.6142 d.sub.18 = 0.4453 r.sub.19 = d.sub.19 = 0.8000 n.sub.d10 = 1.51633 .sub.d10 = 64.14 r.sub.20 = d.sub.20 = 1.8000 n.sub.d11 = 1.54771 .sub.d11 = 62.84 r.sub.21 = d.sub.21 = 0.5000 r.sub.22 = d.sub.22 = 0.5000 n.sub.d12 = 1.51633 .sub.d12 = 64.14 r.sub.23 = d.sub.23 = 1.2588 r.sub.24 = (Image Plane) Aspherical Coefficients 4th surface K = 42.6072 A.sub.4 = 4.5281 10.sup.4 A.sub.6 = 1.2752 10.sup.6 A.sub.8 = 2.9327 10.sup.7 A.sub.10 = 0 7th surface K = 0 A.sub.4 = 2.9136 10.sup.4 A.sub.6 = 7.7511 10.sup.7 A.sub.8 = 2.4221 10.sup.8 A.sub.10 = 0 17th surface K = 0 A.sub.4 = 8.0585 10.sup.4 A.sub.6 = 1.7583 10.sup.5 A.sub.8 = 1.1309 10.sup.6 A.sub.10 = 0 Zooming Data () WE ST TE f (mm) 4.71141 7.84455 13.21508 FNO 2.8000 3.6612 5.0650 2 () 67.8 41.2 24.8 d.sub.5 10.20144 4.70557 1.12127 d.sub.6 7.09024 5.59391 1.24849 d.sub.12 3.08267 9.70509 10.04403 d.sub.16 0.98577 1.28696 8.72623

Example 3

(65) TABLE-US-00003 r.sub.1 = 22.0799 d.sub.1 = 0.7823 n.sub.d1 = 1.80400 .sub.d1 = 46.57 r.sub.2 = 7.0105 d.sub.2 = 1.1905 r.sub.3 = d.sub.3 = 3.8000 n.sub.d2 = 1.80400 .sub.d2 = 46.57 r.sub.4 = (Mirror) d.sub.4 = 3.4483 n.sub.d3 = 1.80400 .sub.d3 = 46.57 r.sub.5 = d.sub.5 = 0.4000 r.sub.6 = 43.4610 d.sub.6 = 0.7742 n.sub.d4 = 1.77250 .sub.d4 = 49.60 r.sub.7 = 9.6384 d.sub.7 = 0.6369 r.sub.8 = 19.1908 (Aspheric) d.sub.8 = 1.6810 n.sub.d5 = 1.84666 .sub.d5 = 23.78 r.sub.9 = 40.1274 d.sub.9 = (Variable) r.sub.10 = (Stop) d.sub.10 = 0.5000 r.sub.11 = 85.1662 d.sub.11 = 1.5117 n.sub.d6 = 1.58913 .sub.d6 = 61.26 r.sub.12 = 18.3807 d.sub.12 = (Variable) r.sub.13 = 5.5347 (Aspheric) d.sub.13 = 2.9473 n.sub.d7 = 1.48749 .sub.d7 = 70.23 r.sub.14 = 102.8346 d.sub.14 = 0.1500 r.sub.15 = 68.5128 d.sub.15 = 3.4582 n.sub.d8 = 1.84666 .sub.d8 = 23.78 r.sub.16 = 5.6774 d.sub.16 = 2.1376 r.sub.17 = 7.8453 d.sub.17 = 2.3148 n.sub.d9 = 1.60542 .sub.d9 = 45.99 r.sub.18 = 12.6010 d.sub.18 = 0.5441 r.sub.19 = 6.0465 d.sub.19 = 0.7255 n.sub.d10 = 1.61800 .sub.d10 = 63.33 r.sub.20 = 17.9513 d.sub.20 = (Variable) r.sub.21 = 17.2238 d.sub.21 = 1.4117 n.sub.d11 = 1.58913 .sub.d11 = 61.26 (Aspheric) r.sub.22 = 9.8048 d.sub.22 = 0.5599 r.sub.23 = d.sub.23 = 0.8000 n.sub.d12 = 1.51633 .sub.d12 = 64.14 r.sub.24 = d.sub.24 = 1.8000 n.sub.d13 = 1.54771 .sub.d13 = 62.84 r.sub.25 = d.sub.25 = 0.5000 r.sub.26 = d.sub.26 = 0.5000 n.sub.d14 = 1.51633 .sub.d14 = 64.14 r.sub.27 = d.sub.27 = 1.3641 r.sub.28 = (Image Plane) Aspherical Coefficients 8th surface K = 1.5876 A.sub.4 = 2.6616 10.sup.4 A.sub.6 = 3.3939 10.sup.6 A.sub.8 = 1.0023 10.sup.7 A.sub.10 = 0 13th surface K = 0 A.sub.4 = 2.7230 10.sup.4 A.sub.6 = 5.7432 10.sup.6 A.sub.8 = 3.4301 10.sup.7 A.sub.10 = 0 21th surface K = 0 A.sub.4 = 8.9975 10.sup.4 A.sub.6 = 1.8358 10.sup.5 A.sub.8 = 1.4143 10.sup.6 A.sub.10 = 0 Zooming Data () WE ST TE f (mm) 4.60758 7.85021 13.40785 FNO 2.8000 3.4489 4.6187 2 () 65.3 39.0 22.9 d.sub.9 14.75212 6.67783 2.00000 d.sub.12 0.67500 4.26744 1.54139 d.sub.20 1.35767 6.03580 13.51290

Example 4

(66) TABLE-US-00004 r.sub.1 = 29.0184 d.sub.1 = 0.7437 n.sub.d1 = 1.80400 .sub.d1 = 46.57 r.sub.2 = 7.3275 d.sub.2 = 1.3049 r.sub.3 = d.sub.3 = 4.0000 n.sub.d2 = 1.80400 .sub.d2 = 46.57 r.sub.4 = (Mirror) d.sub.4 = 3.5133 n.sub.d3 = 1.80400 .sub.d3 = 46.57 r.sub.5 = d.sub.5 = 0.3000 r.sub.6 = 31.2038 d.sub.6 = 0.7673 n.sub.d4 = 1.80400 .sub.d4 = 46.57 r.sub.7 = 15.2085 d.sub.7 = 1.5760 r.sub.8 = 33.1818 d.sub.8 = 1.5628 n.sub.d5 = 1.84666 .sub.d5 = 23.78 (Aspheric) r.sub.9 = 29.4113 d.sub.9 = (Variable) r.sub.10 = (Stop) d.sub.10 = 0.5000 r.sub.11 = 20.3172 d.sub.11 = 1.9876 n.sub.d6 = 1.58913 .sub.d6 = 61.26 (Aspheric) r.sub.12 = 14.3558 d.sub.12 = 0.1387 r.sub.13 = 7.0863 d.sub.13 = 2.5021 n.sub.d7 = 1.48749 .sub.d7 = 70.23 r.sub.14 = 521.1337 d.sub.14 = 0.0001 r.sub.15 = 217.6721 d.sub.15 = 5.9501 n.sub.d8 = 1.84666 .sub.d8 = 23.78 r.sub.16 = 4.5340 d.sub.16 = (Variable) r.sub.17 = 10.1062 d.sub.17 = 1.8686 n.sub.d9 = 1.60300 .sub.d9 = 65.44 r.sub.18 = 46.5940 d.sub.18 = (Variable) r.sub.19 = 22.5387 d.sub.19 = 2.3721 n.sub.d10 = 1.58913 .sub.d10 = 61.26 (Aspheric) r.sub.20 = 5.8538 d.sub.20 = 0.4297 r.sub.21 = d.sub.21 = 0.8000 n.sub.d11 = 1.51633 .sub.d11 = 64.14 r.sub.22 = d.sub.22 = 0.8000 n.sub.d12 = 1.54771 .sub.d12 = 62.84 r.sub.23 = d.sub.23 = 0.5000 r.sub.24 = d.sub.24 = 0.5000 n.sub.d13 = 1.51633 .sub.d13 = 64.14 r.sub.25 = d.sub.25 = 1.3824 r.sub.27 = (Image Plane) Aspherical Coefficients 8th surface K = 1.9221 A.sub.4 = 1.0674 10.sup.4 A.sub.6 = 7.5509 10.sup.7 A.sub.8 = 6.9692 10.sup.8 A.sub.10 = 0 11th surface K = 0 A.sub.4 = 1.4582 10.sup.4 A.sub.6 = 4.2034 10.sup.8 A.sub.8 = 1.1204 10.sup.8 A.sub.10 = 0 19th surface K = 0 A.sub.4 = 1.8514 10.sup.3 A.sub.6 = 6.5803 10.sup.6 A.sub.8 = 9.0686 10.sup.7 A.sub.10 = 0 Zooming Data () WE ST TE f (mm) 4.65117 7.85007 13.29161 FNO 2.5000 3.4944 4.8337 2 () 68.4 41.7 24.7 d.sub.9 13.35295 7.17214 2.00000 d.sub.16 1.22323 4.89168 2.01917 d.sub.18 0.94992 3.89804 12.56077

Example 5

(67) TABLE-US-00005 r.sub.1 = 15.9959 d.sub.1 = 2.0000 n.sub.d1 = 1.84666 .sub.d1 = 23.78 r.sub.2 = 17.9366 d.sub.2 = 0.8000 (Aspheric) r.sub.3 = 122.3665 d.sub.3 = 1.0000 n.sub.d2 = 1.72916 .sub.d2 = 54.68 r.sub.4 = 6.1500 d.sub.4 = 1.9000 r.sub.5 = d.sub.5 = 4.1000 n.sub.d3 = 1.56883 .sub.d3 = 56.36 r.sub.6 = (Mirror) d.sub.6 = 3.9000 n.sub.d4 = 1.56883 .sub.d4 = 56.36 r.sub.7 = d.sub.7 = (Variable) r.sub.8 = (Stop) d.sub.8 = 0.5928 r.sub.9 = 14.1418 d.sub.9 = 3.0000 n.sub.d5 = 1.80610 .sub.d5 = 40.92 (Aspheric) r.sub.10 = 138.1914 d.sub.10 = (Variable) r.sub.11 = 9.2691 d.sub.11 = 3.2000 n.sub.d6 = 1.48749 .sub.d6 = 70.23 r.sub.12 = 18.4588 d.sub.12 = 1.0064 n.sub.d7 = 1.84666 .sub.d7 = 23.78 r.sub.13 = 7.4386 d.sub.13 = 0.5000 r.sub.14 = 9.1725 d.sub.14 = 2.4000 n.sub.d8 = 1.80518 .sub.d8 = 25.42 r.sub.15 = 16.4170 d.sub.15 = (Variable) r.sub.16 = 44.6119 d.sub.16 = 0.8000 n.sub.d9 = 1.84666 .sub.d9 = 23.78 r.sub.17 = 8.9511 d.sub.17 = (Variable) (Aspheric) r.sub.18 = 11.2550 d.sub.18 = 2.6000 n.sub.d10 = 1.58913 .sub.d10 = 61.26 r.sub.19 = 673.2282 d.sub.19 = (Variable) (Aspheric) r.sub.20 = d.sub.20 = 1.5000 n.sub.d11 = 1.51633 .sub.d11 = 64.14 r.sub.21 = d.sub.21 = 1.4400 n.sub.d12 = 1.54771 .sub.d12 = 62.84 r.sub.22 = d.sub.22 = 0.8000 r.sub.23 = d.sub.23 = 0.8000 n.sub.d13 = 1.51633 .sub.d13 = 64.14 r.sub.24 = d.sub.24 = 1.0000 r.sub.25 = (Image Plane) Aspherical Coefficients 2nd surface K = 0 A.sub.4 = 2.1855 10.sup.4 A.sub.6 = 3.4923 10.sup.7 A.sub.8 = 0 A.sub.10 = 0 9th surface K = 5.1530 A.sub.4 = 2.4340 10.sup.4 A.sub.6 = 7.4872 10.sup.6 A.sub.8 = 2.0515 10.sup.7 A.sub.10 = 1.0188 10.sup.8 17th surface K = 3.7152 A.sub.4 = 1.2209 10.sup.3 A.sub.6 = 1.7576 10.sup.5 A.sub.8 = 2.5810 10.sup.6 A.sub.10 = 1.2193 10.sup.7 19th surface K = 1.4583 A.sub.4 = 1.5578 10.sup.4 A.sub.6 = 1.1072 10.sup.5 A.sub.8 = 5.6481 10.sup.7 A.sub.10 = 8.6742 10.sup.9 Zooming Data () WE ST TE f (mm) 5.43000 10.61200 15.80000 FNO 2.7116 3.7726 4.5293 2 () 63.5 35.7 24.5 d.sub.7 13.12435 4.47821 0.50000 d.sub.10 0.81880 1.71785 0.50000 d.sub.15 0.60000 2.00387 4.09707 d.sub.17 1.40000 8.20925 11.93740 d.sub.19 2.71758 2.25155 1.62627

Example 6

(68) TABLE-US-00006 r.sub.1 = 49.3427 d.sub.1 = 2.0000 n.sub.d1 = 1.84666 .sub.d1 = 23.78 r.sub.2 = 115.4656 d.sub.2 = 0.4000 r.sub.3 = 52.5304 d.sub.3 = 1.0000 n.sub.d2 = 1.69350 .sub.d2 = 53.21 (Aspheric) r.sub.4 = 5.8428 d.sub.4 = 1.8000 r.sub.5 = d.sub.5 = 4.0000 n.sub.d3 = 1.56883 .sub.d3 = 56.36 r.sub.6 = (Mirror) d.sub.6 = 3.8000 n.sub.d4 = 1.56883 .sub.d4 = 56.36 r.sub.7 = d.sub.7 = (Variable) r.sub.8 = (Stop) d.sub.8 = 0.6000 r.sub.9 = 8.0295 (Aspheric) d.sub.9 = 2.8000 n.sub.d5 = 1.69350 .sub.d5 = 53.21 r.sub.10 = 5.9145 d.sub.10 = 0.8000 n.sub.d6 = 1.80440 .sub.d6 = 39.59 r.sub.11 = 12.3640 d.sub.11 = (Variable) r.sub.12 = 26.8805 d.sub.12 = 0.8000 n.sub.d7 = 1.84666 .sub.d7 = 23.78 r.sub.13 = 7.1849 d.sub.13 = (Variable) (Aspheric) r.sub.14 = 10.7803 d.sub.14 = 3.1000 n.sub.d8 = 1.48749 .sub.d8 = 70.23 r.sub.15 = 52.9481 d.sub.15 = (Variable) r.sub.16 = d.sub.16 = 1.5000 n.sub.d9 = 1.51633 .sub.d9 = 64.14 r.sub.17 = d.sub.17 = 1.4400 n.sub.d10 = 1.54771 .sub.d10 = 62.84 r.sub.18 = d.sub.18 = 0.8000 r.sub.19 = d.sub.19 = 0.8000 n.sub.d11 = 1.51633 .sub.d11 = 64.14 r.sub.20 = d.sub.20 = 1.0000 r.sub.21 = (Image Plane) Aspherical Coefficients 3rd surface K = 0 A.sub.4 = 2.6048 10.sup.4 A.sub.6 = 3.2365 10.sup.6 A.sub.8 = 2.2913 10.sup.8 A.sub.10 = 0 9th surface K = 0 A.sub.4 = 3.0615 10.sup.4 A.sub.6 = 2.0330 10.sup.6 A.sub.8 = 1.0403 10.sup.7 A.sub.10 = 0 13th surface K = 3.5241 A.sub.4 = 1.8328 10.sup.3 A.sub.6 = 1.6164 10.sup.5 A.sub.8 = 3.5495 10.sup.6 A.sub.10 = 1.2410 10.sup.7 Zooming Data () WE ST TE f (mm) 5.38001 8.50001 13.45001 FNO 3.0358 3.8702 4.5606 2 () 65.8 43.8 28.4 d.sub.7 11.53527 6.15290 0.50000 d.sub.11 2.10162 2.49863 3.68430 d.sub.13 3.96820 9.09478 10.56416 d.sub.15 1.75491 1.61369 4.61155

Example 7

(69) TABLE-US-00007 r.sub.1 = 21.0760 d.sub.1 = 1.4000 n.sub.d1 = 1.74320 .sub.d1 = 49.34 r.sub.2 = 7.9352 (Aspheric) d.sub.2 = 2.8000 r.sub.3 = d.sub.3 = 6.5000 n.sub.d2 = 1.56883 .sub.d2 = 56.36 r.sub.4 = (Mirror) d.sub.4 = 6.0000 n.sub.d3 = 1.56883 .sub.d3 = 56.36 r.sub.5 = d.sub.5 = 0.8000 r.sub.6 = 18.8610 d.sub.6 = 0.8000 n.sub.d4 = 1.72916 .sub.d4 = 54.68 r.sub.7 = 29.7460 d.sub.7 = 0.5273 r.sub.8 = 25.1850 d.sub.8 = 1.9000 n.sub.d5 = 1.84666 .sub.d5 = 23.78 r.sub.9 = 121.8149 d.sub.9 = (Variable) r.sub.10 = (Stop) d.sub.10 = 0.8000 r.sub.11 = 11.8772 d.sub.11 = 1.9992 n.sub.d6 = 1.49700 .sub.d6 = 81.54 (Aspheric) r.sub.12 = 22.2117 d.sub.12 = 0.3000 r.sub.13 = 8.0295 d.sub.13 = 1.9997 n.sub.d7 = 1.48749 .sub.d7 = 70.23 r.sub.14 = 16.2855 d.sub.14 = 0.7997 n.sub.d8 = 1.64769 .sub.d8 = 33.79 r.sub.15 = 52.6732 d.sub.15 = 0.3000 r.sub.16 = 7.3242 d.sub.16 = 1.3308 n.sub.d9 = 1.84666 .sub.d9 = 23.78 r.sub.17 = 4.4772 d.sub.17 = 1.2000 r.sub.18 = 17.2769 d.sub.18 = 1.1317 n.sub.d10 = 1.80610 .sub.d10 = 40.92 r.sub.19 = 6.2199 d.sub.19 = (Variable) r.sub.20 = 9.0812 d.sub.20 = 2.0000 n.sub.d11 = 1.61800 .sub.d11 = 63.33 r.sub.21 = 19.8406 d.sub.21 = (Variable) r.sub.22 = 34.2139 d.sub.22 = 2.0000 n.sub.d12 = 1.58313 .sub.d12 = 59.38 (Aspheric) r.sub.23 = 9.7728 d.sub.23 = 1.0032 r.sub.24 = d.sub.25 = 1.4400 n.sub.d13 = 1.54771 .sub.d13 = 62.84 r.sub.25 = d.sub.26 = 0.8000 r.sub.26 = d.sub.27 = 0.8000 n.sub.d14 = 1.51633 .sub.d14 = 64.14 r.sub.27 = d.sub.28 = 1.0003 r.sub.28 = (Image Plane) Aspherical Coefficients 2nd surface K = 0 A.sub.4 = 9.3483 10.sup.5 A.sub.6 = 1.4787 10.sup.7 A.sub.8 = 4.5620 10.sup.8 A.sub.10 = 0 11th surface K = 0 A.sub.4 = 2.6863 10.sup.4 A.sub.6 = 1.0879 10.sup.7 A.sub.8 = 3.8711 10.sup.9 A.sub.10 = 0 22nd surface K = 0 A.sub.4 = 4.8081 10.sup.4 A.sub.6 = 5.9535 10.sup.6 A.sub.8 = 1.6767 10.sup.7 A.sub.10 = 0 Zooming Data () WE ST TE f (mm) 5.80000 9.17005 14.49992 FNO 2.6880 3.4974 4.5402 2 () 60.8 40.1 25.4 d.sub.9 14.10553 7.78994 2.48873 d.sub.19 1.54225 5.16705 2.56297 d.sub.21 2.32790 5.01801 12.92472

Example 8

(70) TABLE-US-00008 r.sub.1 = 16.1825 d.sub.1 = 1.4000 n.sub.d1 = 1.80610 .sub.d1 = 40.92 (Aspheric) r.sub.2 = 7.3872 d.sub.2 = 3.5000 r.sub.3 = d.sub.3 = 6.5000 n.sub.d2 = 1.60311 .sub.d2 = 60.64 r.sub.4 = (Mirror) d.sub.4 = 6.0000 n.sub.d3 = 1.60311 .sub.d3 = 60.64 r.sub.5 = d.sub.5 = 0.7950 r.sub.6 = 27.1461 d.sub.6 = 0.8000 n.sub.d4 = 1.72916 .sub.d4 = 54.68 r.sub.7 = 20.2982 d.sub.7 = 0.5273 r.sub.8 = 17.2255 d.sub.8 = 1.9000 n.sub.d5 = 1.84666 .sub.d5 = 23.78 r.sub.9 = 90.2451 d.sub.9 = (Variable) r.sub.10 = (Stop) d.sub.10 = 0.8000 r.sub.11 = 17.0416 d.sub.11 = 1.9965 n.sub.d6 = 1.56384 .sub.d6 = 60.67 (Aspheric) r.sub.12 = 13.7245 d.sub.12 = 0.5000 r.sub.13 = 5.5039 d.sub.13 = 3.7857 n.sub.d7 = 1.48749 .sub.d7 = 70.23 r.sub.14 = 38.8943 d.sub.14 = 0.8000 n.sub.d8 = 1.69895 .sub.d8 = 30.13 r.sub.15 = 4.2611 d.sub.15 = (Variable) r.sub.16 = 16.8715 d.sub.16 = 2.0000 n.sub.d9 = 1.48749 .sub.d9 = 70.23 r.sub.17 = 96.4706 d.sub.17 = (Variable) r.sub.18 = 60.1937 d.sub.18 = 2.0000 n.sub.d10 = 1.56384 .sub.d10 = 60.67 r.sub.19 = 11.5463 d.sub.19 = 1.0039 (Aspheric) r.sub.20 = d.sub.20 = 1.4400 n.sub.d11 = 1.54771 .sub.d11 = 62.84 r.sub.21 = d.sub.21 = 0.8000 r.sub.22 = d.sub.22 = 0.8000 n.sub.d12 = 1.51633 .sub.d12 = 64.14 r.sub.23 = d.sub.23 = 1.0021 r.sub.24 = (Image Plane) Aspherical Coefficients 1st surface K = 0 A.sub.4 = 5.1308 10.sup.5 A.sub.6 = 2.3428 10.sup.7 A.sub.8 = 3.7916 10.sup.9 A.sub.10 = 7.2819 10.sup.11 11th surface K = 0 A.sub.4 = 1.6960 10.sup.4 A.sub.6 = 1.0587 10.sup.6 A.sub.8 = 5.6885 10.sup.8 A.sub.10 = 2.0816 10.sup.10 19th surface K = 0 A.sub.4 = 2.9238 10.sup.4 A.sub.6 = 1.4179 10.sup.5 A.sub.8 = 6.7945 10.sup.7 A.sub.10 = 1.6439 10.sup.8 Zooming Data () WE ST TE f (mm) 5.80001 9.17026 14.49938 FNO 2.6926 3.5230 4.5194 2 () 61.1 40.1 25.7 d.sub.9 14.09978 8.00554 2.48873 d.sub.15 2.47558 7.50212 3.24411 d.sub.17 3.07729 4.13993 13.92316

Example 9

(71) TABLE-US-00009 r.sub.1 = 21.2658 d.sub.1 = 1.0000 n.sub.d1 = 1.74100 .sub.d1 = 52.64 r.sub.2 = 8.6245 d.sub.2 = 3.3711 r.sub.3 = d.sub.3 = 5.8400 n.sub.d2 = 1.80400 .sub.d2 = 46.57 r.sub.4 = (Mirror) d.sub.4 = 5.4952 n.sub.d3 = 1.80400 .sub.d3 = 46.57 r.sub.5 = d.sub.5 = 0.3221 r.sub.6 = 300.0000 d.sub.6 = 1.0000 n.sub.d4 = 1.74320 .sub.d4 = 49.34 r.sub.7 = 15.3314 d.sub.7 = 0.5979 (Aspheric) r.sub.8 = 15.8974 d.sub.8 = 1.4903 n.sub.d5 = 1.84666 .sub.d5 = 23.78 r.sub.9 = 43.0822 d.sub.9 = (Variable) r.sub.10 = (Stop) d.sub.10 = 0.6000 r.sub.11 = 63.9771 d.sub.11 = 1.3913 n.sub.d6 = 1.61800 .sub.d6 = 63.33 r.sub.12 = 23.2380 d.sub.12 = (Variable) r.sub.13 = 7.9674 d.sub.13 = 2.3478 n.sub.d7 = 1.48749 .sub.d7 = 70.23 (Aspheric) r.sub.14 = 68.3182 d.sub.14 = 0.1000 r.sub.15 = 24.3652 d.sub.15 = 3.3012 n.sub.d8 = 1.84666 .sub.d8 = 23.78 r.sub.16 = 7.7880 d.sub.16 = 0.2484 r.sub.17 = 9.2912 d.sub.17 = 2.1349 n.sub.d9 = 1.72916 .sub.d9 = 54.68 r.sub.18 = 19.4929 d.sub.18 = 0.7000 n.sub.d10 = 1.53172 .sub.d10 = 48.84 r.sub.19 = 5.2999 d.sub.19 = (Variable) r.sub.20 = 22.5496 d.sub.20 = 2.5068 n.sub.d11 = 1.58913 .sub.d11 = 61.14 (Aspheric) r.sub.21 = 6.5395 d.sub.21 = 1.0000 r.sub.22 = d.sub.22 = 1.5000 n.sub.d12 = 1.51633 .sub.d12 = 64.14 r.sub.23 = d.sub.23 = 1.4400 n.sub.d13 = 1.54771 .sub.d13 = 62.84 r.sub.24 = d.sub.24 = 0.8000 r.sub.25 = d.sub.25 = 0.8000 n.sub.d14 = 1.51633 .sub.d14 = 64.14 r.sub.26 = d.sub.26 = 1.0894 r.sub.27 = (Image Plane) Aspherical Coefficients 7th surface K = 0 A.sub.4 = 6.9423 10.sup.5 A.sub.6 = 1.9216 10.sup.7 A.sub.8 = 2.3395 10.sup.8 A.sub.10 = 0 13th surface K = 0 A.sub.4 = 2.1881 10.sup.4 A.sub.6 = 2.0288 10.sup.6 A.sub.8 = 7.6472 10.sup.10 A.sub.10 = 0 20th surface K = 0 A.sub.4 = 1.0095 10.sup.3 A.sub.6 = 3.4022 10.sup.8 A.sub.8 = 1.7165 10.sup.7 A.sub.10 = 0 Zooming Data () WE ST TE f (mm) 5.52179 7.96811 15.98093 FNO 2.4770 2.9873 4.5000 2 () 64.5 44.7 22.7 d.sub.9 17.73448 10.81643 2.00000 d.sub.12 1.20000 3.80000 3.50000 d.sub.19 2.60300 5.58623 15.86209

Example 10

(72) TABLE-US-00010 r.sub.1 = 24.8917 d.sub.1 = 1.0000 n.sub.d1 = 1.74100 .sub.d1 = 52.64 r.sub.2 = 8.0792 d.sub.2 = 2.3760 r.sub.3 = d.sub.3 = 5.2400 n.sub.d2 = 1.80400 .sub.d2 = 46.57 r.sub.4 = (Mirror) d.sub.4 = 5.0006 n.sub.d3 = 1.80400 .sub.d3 = 46.57 r.sub.5 = d.sub.5 = 0.2922 r.sub.6 = 300.0000 d.sub.6 = 1.0000 n.sub.d4 = 1.74320 .sub.d4 = 49.34 r.sub.7 = 14.5213 d.sub.7 = 0.1000 (Aspheric) r.sub.8 = 14.5896 d.sub.8 = 1.7517 n.sub.d5 = 1.84666 .sub.d5 = 23.78 r.sub.9 = 64.9869 d.sub.9 = (Variable) r.sub.10 = (Stop) d.sub.10 = 0.60000 r.sub.11 = 33.4595 d.sub.11 = 1.8985 n.sub.d6 = 1.61800 .sub.d6 = 63.33 r.sub.12 = 11.1499 d.sub.12 = 0.7000 n.sub.d7 = 1.80518 .sub.d7 = 25.42 r.sub.13 = 20.0542 d.sub.13 = (Variable) r.sub.14 = 10.2987 d.sub.14 = 2.0299 n.sub.d8 = 1.48749 .sub.d8 = 70.23 (Aspheric) r.sub.15 = 18890.0000 d.sub.15 = 0.1000 r.sub.16 = 19.8062 d.sub.16 = 4.5045 n.sub.d9 = 1.84666 .sub.d9 = 23.78 r.sub.17 = 9.7836 d.sub.17 = 0.2000 r.sub.18 = 11.2175 d.sub.18 = 1.7598 n.sub.d10 = 1.72916 .sub.d10 = 54.68 r.sub.19 = 51.5183 d.sub.19 = 0.7000 n.sub.d11 = 1.53172 .sub.d11 = 48.84 r.sub.20 = 5.5430 d.sub.20 = (Variable) r.sub.21 = 23.0137 d.sub.21 = 1.9685 n.sub.d12 = 1.58913 .sub.d12 = 61.14 (Aspheric) r.sub.22 = 7.0933 d.sub.22 = 1.0000 r.sub.23 = d.sub.23 = 1.5000 n.sub.d13 = 1.51633 .sub.d13 = 64.14 r.sub.24 = d.sub.24 = 1.4400 n.sub.d14 = 1.54771 .sub.d14 = 62.84 r.sub.25 = d.sub.15 = 0.8000 r.sub.26 = d.sub.16 = 0.8000 n.sub.d15 = 1.51633 .sub.d15 = 64.14 r.sub.27 = d.sub.17 = 1.0106 r.sub.28 = (Image Plane) Aspherical Coefficients 7th surface K = 0 A.sub.4 = 8.0580 10.sup.5 A.sub.6 = 7.6927 10.sup.7 A.sub.8 = 2.7173 10.sup.8 A.sub.10 = 0 14th surface K = 0 A.sub.4 = 1.1033 10.sup.4 A.sub.6 = 1.4285 10.sup.8 A.sub.8 = 1.8629 10.sup.8 A.sub.10 = 0 21st surface K = 0 A.sub.4 = 8.5891 10.sup.4 A.sub.6 = 1.0215 10.sup.5 A.sub.8 = 3.2143 10.sup.7 A.sub.10 = 0 Zooming Data () WE ST TE f (mm) 5.86879 9.99877 17.39648 FNO 2.4340 3.2140 4.5000 2 () 61.4 35.8 21.0 d.sub.9 17.88781 8.41716 2.00000 d.sub.13 1.20000 6.81663 3.50000 d.sub.20 3.14136 7.01231 16.74709

Example 11

(73) TABLE-US-00011 r.sub.1 = 41.9739 d.sub.1 = 1.2000 n.sub.d1 = 1.77250 .sub.d1 = 49.60 r.sub.2 = 11.1642 d.sub.2 = 2.9000 r.sub.3 = d.sub.3 = 6.5000 n.sub.d2 = 1.78590 .sub.d2 = 44.20 r.sub.4 = (Mirror) d.sub.4 = 6.0000 n.sub.d3 = 1.78590 .sub.d3 = 44.20 r.sub.5 = d.sub.5 = 0.3971 r.sub.6 = 28.0000 d.sub.6 = 1.2000 n.sub.d4 = 1.74330 .sub.d4 = 49.33 r.sub.7 = 11.3578 d.sub.7 = 0.3457 (Aspheric) r.sub.8 = 9.4845 d.sub.8 = 1.7925 n.sub.d5 = 1.84666 .sub.d5 = 23.78 r.sub.9 = 14.2959 d.sub.9 = (Variable) r.sub.10 = (Stop) d.sub.10 = 1.0000 r.sub.11 = 47.8757 d.sub.11 = 1.9600 n.sub.d6 = 1.72916 .sub.d6 = 54.68 r.sub.12 = 9.0806 d.sub.12 = 0.7000 n.sub.d7 = 1.72825 .sub.d7 = 28.46 r.sub.13 = 25.4395 d.sub.13 = (Variable) r.sub.14 = 9.1761 d.sub.14 = 1.9500 n.sub.d8 = 1.74330 .sub.d8 = 49.33 (Aspheric) r.sub.15 = 75.3616 d.sub.15 = 0.8461 r.sub.16 = 24.3002 d.sub.16 = 3.8969 n.sub.d9 = 1.74330 .sub.d9 = 49.33 r.sub.17 = d.sub.17 = 1.0000 n.sub.d10 = 1.72825 .sub.d10 = 28.46 r.sub.18 = 4.8249 d.sub.18 = (Variable) r.sub.19 = 49.5382 d.sub.19 = 2.7500 n.sub.d11 = 1.69350 .sub.d11 = 53.20 r.sub.20 = 10.0407 d.sub.20 = 0.8269 (Aspheric) r.sub.21 = d.sub.21 = 1.4400 n.sub.d12 = 1.54771 .sub.d12 = 62.84 r.sub.22 = d.sub.22 = 0.8000 r.sub.23 = d.sub.23 = 0.8000 n.sub.d13 = 1.51633 .sub.d13 = 64.14 r.sub.24 = d.sub.24 = 1.0447 r.sub.25 = (Image Plane) Aspherical Coefficients 7th surface K = 0 A.sub.4 = 2.2504 10.sup.5 A.sub.6 = 2.6875 10.sup.6 A.sub.8 = 1.2962 10.sup.7 A.sub.10 = 2.8718 10.sup.9 14th surface K = 0 A.sub.4 = 9.8664 10.sup.5 A.sub.6 = 4.0400 10.sup.6 A.sub.8 = 4.4986 10.sup.7 A.sub.10 = 1.3851 10.sup.8 20th surface K = 0 A.sub.4 = 5.3089 10.sup.4 A.sub.6 = 1.6198 10.sup.5 A.sub.8 = 4.4581 10.sup.7 A.sub.10 = 4.9080 10.sup.9 Zooming Data () WE ST TE f (mm) 6.02622 9.31725 14.28897 FNO 2.7652 3.4888 4.5271 2 () 62.4 42.8 28.7 d.sub.9 14.24100 6.97804 2.00694 d.sub.13 2.10000 6.51339 5.34809 d.sub.18 2.46549 5.31403 11.45279

Example 12

(74) TABLE-US-00012 r.sub.1 = 14.2761 d.sub.1 = 5.1000 n.sub.d1 = 1.50913 .sub.d1 = 56.20 (Aspheric) r.sub.2 = (Mirror) d.sub.2 = 5.7941 n.sub.d2 = 1.50913 .sub.d2 = 56.20 r.sub.3 = d.sub.3 = 2.1000 r.sub.4 = 6.4892 d.sub.4 = 0.8000 n.sub.d3 = 1.64000 .sub.d3 = 60.07 r.sub.5 = 84.1654 d.sub.5 = 1.1935 n.sub.d4 = 1.84666 .sub.d4 = 23.78 r.sub.6 = 16.8306 d.sub.6 = (Variable) r.sub.7 = (Stop) d.sub.7 = 0.4000 r.sub.8 = 34.9225 d.sub.8 = 1.4006 n.sub.d5 = 1.74330 .sub.d5 = 49.33 (Aspheric) r.sub.9 = 15.2934 d.sub.9 = 0.1500 r.sub.10 = 6.1210 d.sub.10 = 3.3481 n.sub.d6 = 1.61800 .sub.d6 = 63.33 r.sub.11 = 27.4556 d.sub.11 = 0.8000 n.sub.d7 = 1.84666 .sub.d7 = 23.78 r.sub.12 = 4.9467 d.sub.12 = (Variable) r.sub.13 = 13.6380 d.sub.13 = 1.4415 n.sub.d8 = 1.51633 .sub.d8 = 64.14 r.sub.14 = 143.7586 d.sub.14 = (Variable) r.sub.15 = 19.5436 d.sub.15 = 1.3641 n.sub.d9 = 1.58913 .sub.d9 = 61.25 r.sub.16 = 7.1346 d.sub.16 = 0.8000 (Aspheric) r.sub.17 = d.sub.17 = 1.0500 n.sub.d10 = 1.54771 .sub.d10 = 62.84 r.sub.18 = d.sub.18 = 0.8000 r.sub.19 = d.sub.19 = 0.8000 n.sub.d11 = 1.51633 .sub.d11 = 64.14 r.sub.20 = d.sub.20 = 0.9669 r.sub.21 = (Image Plane) Aspherical Coefficients 1st surface K = 0 A.sub.4 = 3.2165 10.sup.4 A.sub.6 = 9.1756 10.sup.7 A.sub.8 = 4.1788 10.sup.9 A.sub.10 = 0.0000 8th surface K = 0 A.sub.4 = 1.2083 10.sup.4 A.sub.6 = 1.1516 10.sup.7 A.sub.8 = 2.9381 10.sup.8 A.sub.10 = 0.0000 16th surface K = 0 A.sub.4 = 1.3137 10.sup.3 A.sub.6 = 2.0878 10.sup.5 A.sub.8 = 4.9397 10.sup.7 A.sub.10 = 0.0000 Zooming Data () WE ST TE f (mm) 5.02898 8.69474 14.52092 FNO 2.6544 3.5217 4.5079 2 () 64.8 38.2 22.6 d.sub.6 14.61860 7.39251 1.80000 d.sub.12 3.75585 8.20107 4.39975 d.sub.14 3.16733 5.96897 15.38987

(75) Aberration diagrams for Example 1 and Example 2 upon focused on an object point at infinity are shown in FIG. 13 and FIG. 14, respectively. In these aberration diagrams, spherical aberrations SA, astigmatisms AS, distortions DT and chromatic aberrations of magnification CC are illustrated at the wide-angle end (a), intermediate or standard state (b) and telephoto end (c).

(76) Enumerated below are the values of L, d/L, D.sub.FT/f.sub.T, M.sub.3/M.sub.2, f.sub.11/f.sub.12, .sub.Rt, a, and t.sub.LPF concerning conditions (a) to (f) in the aforesaid examples.

(77) TABLE-US-00013 Ex. L d/L D.sub.FT/f.sub.T M.sub.3/M.sub.2 f.sub.11/f.sub.12 1 5.6 0.72088 0.78471 1.19347 0.12343 2 6.0 0.79009 0.76004 0.53348 0.32094 3 5.6 0.71748 0.11496 0.93206 0.36284 4 6.0 0.69413 0.15191 0.92989 0.20195 5 6.64 0.76797 0.25931 3rd-negative 0 6 6.64 0.74877 0.27393 3rd-negative 0 7 6.64 1.19996 0.17676 0.91213 0.37232 8 6.64 1.17430 0.22374 0.93381 0.39484 9 6.64 0.94629 0.21901 0.85382 0.22917 10 6.64 0.85491 0.20119 0.85523 0.05553 11 6.64 0.94867 0.37452 0.73366 0.09671 12 6.0 1.20313 0.30301 0.95350 1.26698 Ex. .sub.Rt a t.sub.LPF 1 1.6884 3.0 1.80 2 1.19598 3.0 1.80 3 1.49396 3.0 1.80 4 1.26884 3.0 0.80 5 1.51672 3.0 1.55 6 1.38530 3.0 1.44 7 1.26560 3.0 1.44 8 1.30121 3.0 1.44 9 1.05735 3.0 1.44 10 1.14882 3.0 1.44 11 0.86588 3.0 1.44 12 1.36309 2.5 1.20

(78) How to receive the inventive optical path-bending zoom optical system in place is now explained specifically. FIGS. 15(a) and 15(b) are illustrative of how to receive the optical path-bending zoom optical system of FIG. 9 (Example 9) in place. FIG. 15(b) is a sectional schematic inclusive of an optical path-bending axis, showing Example 9 of the optical path-bending zoom optical system at the wide-angle end. In this state, two lenses forming the second lens group G2 and the optical path-bending prism P forming a part of the 1-1st lens group G1-1 are relocated in a space between the 1-2nd lens group G1-2 and the second lens group G2, and the negative meniscus lens L1 located in front of the optical path-bending prism P in the 1-1st lens group G1-1 is received in the resulting space, so that the thickness of the optical path-bending zoom optical system in its entrance axis direction (in the depth direction of the camera) can be reduced. It is here noted that when there is a space on the image plane I side with respect to the second lens group G2, it is preferable to relocate the optical path-bending prism P and the 1-2nd lens group G-2 as well as the second lens group G2, etc. on the image plane I side.

(79) FIG. 16 is a conceptual schematic of one embodiment of how to receive the optical path-bending zoom optical system in place when the reflecting optical element is constructed of a mirror M. The mirror M is tilted at a position indicated by a broken line, and lenses L2 and L3 located on the image plane I side with respect to the mirror M are tilted at positions indicated by broken lines, so that the thickness of the zoom optical system in its optical axis direction (in the depth direction of a camera) can be reduced.

(80) FIG. 17 is a conceptual schematic of another embodiment of how to receive the optical path-bending zoom optical system in place when the reflecting optical element is formed of a mirror M. The mirror M is tilted at a position indicated by a broken line and a lens group LG located on the object side with respect to the mirror M is received in the resulting space, thereby achieving similar thickness reductions. Instead of tilting the mirror M, it may be relocated along the optical axis after bending, as shown in FIG. 15.

(81) FIGS. 18(a) and 18(b) are illustrative of one embodiment of the reflecting optical element for bending an optical path, which is constructed of a liquid or transformable prism LP (see FIG. 18(a)). This reflecting optical element may be received in place as by removing the liquid therefrom as shown in FIG. 18(b), thereby achieving thickness reductions. Alternatively, lens groups located on the object side with respect to the prism LP may be received in the resulting space (see FIG. 17), or other lenses may be tilted (see FIG. 16), again achieving thickness reductions.

(82) In the optical path-bending zoom optical system of the present invention, the reflecting optical element for bending an optical path may also be constructed of a variable-shape mirror. The variable-shape mirror is a reflecting mirror comprising a transformable film with a reflecting mirror coating applied thereon. This reflecting mirror may be relocated by folding or winding.

(83) When the reflecting optical element for bending an optical path is constructed of a variable-shape mirror, it is acceptable to carry out focusing by the transformation of that mirror, as shown conceptually in FIG. 19. For focusing on a nearby object, only the transformation of a planar form of variable-shape mirror DM into a concave surface is needed upon focused on a point at infinity, as shown by an arrow. That is, for focusing on a nearby object, the surface shape of the variable-shape mirror DM is transformed into an aspheric surface shape within an effective reflecting surface area. Especially when power is imparted to a reflecting surface that is of rotationally symmetric shape, decentration aberrations are produced at that surface due to decentered incidence of light thereon. It is thus desired that the variable-shape mirror DM be defined by a rotationally asymmetric curved surface.

(84) Off-axis, rotationally asymmetric distortions or the like, too, are produced by decentration. To make correction for decentration aberrations symmetric with respect to plane, it is preferable to transform the surface of the variable-shape mirror DM into a curved surface with respect to plane, where only one symmetric surface is defined by a plane including an optical axis entered in and reflected at the reflecting surface of the variable-shape mirror DM, as shown in FIG. 20.

(85) Referring again to FIG. 19, the variable-shape mirror DM takes a planar form upon focused on a point at infinity. To make correction for decentration aberrations produced upon focused on a nearby object point, however, it is preferable to transform the reflecting surface of the mirror DM into a rotationally asymmetric surface having only one symmetric plane, as shown in FIG. 20. With this arrangement, it is possible to achieve the size reduction of the whole of an electronic image pickup system and maintain its performance.

(86) FIG. 21 is illustrative of one embodiment of how to correct camera movements by tilting the reflecting surface of a variable-shape mirror DM in an arrow direction. In the state of FIG. 19, there is no camera movement, and in the state of FIG. 21, the function of correcting camera movements by tilting the reflecting surface of the variable-shape mirror DM is brought into action. When an image pickup device turns down with respect to a phototaking direction as shown in FIG. 21, the inclination of the reflecting surface of the variable-shape mirror DM displaces from a broken-line position to a solid-line position so that the entrance optical axis is kept from inclination. Preferably in this case, the whole surface shape of the variable-shape mirror DM is so transformed that fluctuations of aberrations can be prevented.

(87) In the present invention, it is acceptable to impart power the reflecting surface of the reflecting optical element for bending an optical path and configure its surface shape with a free-form surface or the like. Alternatively, it is acceptable to construct the reflecting surface of the reflecting optical element with a holographic optical element (HOE).

(88) When the reflecting optical element is constructed of an optical path-bending prism P as set forth in Examples 1 to 12, it is acceptable to cement the prism P to lenses located before and after the same.

(89) When an electronic image pickup system such as a digital camera is constructed using the optical path-bending zoom optical system of the present invention, it is acceptable to interpose an optical path splitter element between the optical path-bending zoom optical system and an electronic image pickup device such as a CCD to split an phototaking optical path to a finder optical path, as shown in FIG. 22. FIG. 22 is a front view of a digital camera 40. In this case, an optical path-bending zoom optical system comprises a reflecting optical element M1 for bending an optical path through 900 and a lens group LA located on the image, plane side of the element M1, with an image pickup device CCD 49 positioned on the image plane. Between the lens group LA and CCD 49, there is interposed an optical path splitter element M2 such as a half-silvered mirror to split the optical path, so that a part thereof is deflected to a side substantially vertical to a plane including an optical axis before and after reflection at the reflecting optical element M1 (the upper side of FIG. 22). It is understood that the optical path splitter element M2 may be defined by a reflecting surface that is inserted only when a light beam is guided to the finder optical path. An optical path reflected at the optical path splitter element M2 is bent by another reflecting surface M3 through 90 in a plane including an optical axis before and after reflected at the optical path splitter element M2 and further bent by a fourth reflecting surface M4 through 90, running substantially parallel with the optical axis entered in the reflecting optical element M1. Although an eyepiece optical system is not shown in FIG. 22, it is understood that it is located on the exit side of the fourth reflecting surface M4 or before and after a plane including that reflecting surface M4, so that a subject image under observation is viewed by the viewer's eyeball positioned on the exit side of the fourth reflecting surface M4.

(90) Throughout Examples 1 to 12, the low-pass filter LF is constructed of three filter elements one upon another. However, it is appreciated that many modifications may be made to the aforesaid examples without departing from the scope of the invention. For instance, the low-pass filter may be formed of one single low-pass filter element.

(91) In each of the aforesaid examples, the final lens group is provided on its image side with a near-infrared cut filter IF or a low-pass filter LF having a near-infrared sharp cut coat surface IC on its entrance surface side. This near-infrared cut filter IF or near-infrared sharp cut coat surface IC is designed to have a transmittance of at least 0.80% at 600 nm wavelength and a transmittance of up to 10% at 700 nm wavelength. More specifically, the low-pass filter has a multilayer structure made up of such 27 layers as mentioned below; however, the design wavelength is 780 nm.

(92) TABLE-US-00014 Substrate Material Physical Thickness (nm) /4 1st layer Al.sub.2O.sub.3 58.96 0.50 2nd layer TiO.sub.2 84.19 1.00 3rd layer SiO.sub.2 134.14 1.00 4th layer TiO.sub.2 84.19 1.00 5th layer SiO.sub.2 134.14 1.00 6th layer TiO.sub.2 84.19 1.00 7th layer SiO.sub.2 134.14 1.00 8th layer TiO.sub.2 84.19 1.00 9th layer SiO.sub.2 134.14 1.00 10th layer TiO.sub.2 84.19 1.00 11th layer SiO.sub.2 134.14 1.00 12th layer TiO.sub.2 84.19 1.00 13th layer SiO.sub.2 134.14 1.00 14th layer TiO.sub.2 84.19 1.00 15th layer SiO.sub.2 178.41 1.33 16th layer TiO.sub.2 101.03 1.21 17th layer SiO.sub.2 167.67 1.25 18th layer TiO.sub.2 96.82 1.15 19th layer SiO.sub.2 147.55 1.05 20th layer TiO.sub.2 84.19 1.00 21st layer SiO.sub.2 160.97 1.20 22nd layer TiO.sub.2 84.19 1.00 23rd layer SiO.sub.2 154.26 1.15 24th layer TiO.sub.2 95.13 1.13 25th layer SiO.sub.2 160.97 1.20 26th layer TiO.sub.2 99.34 1.18 27th layer SiO.sub.2 87.19 0.65

(93) Air

(94) The aforesaid near-infrared sharp cut coat has such transmittance characteristics as shown in FIG. 23.

(95) The low-pass filter LF is provided on its exit surface side with a color filter or coat for reducing the transmission of colors at such a short wavelength band as shown in FIG. 24, thereby enhancing the color reproducibility of electronic images.

(96) Preferably, such a filter or coat should be such that the ratio of the transmittance of 420 nm wavelength with respect to the transmittance of a wavelength in the range of 400 nm to 700 nm at which the highest transmittance is found is at least 15% and that the ratio of 400 nm wavelength with respect to the highest wavelength transmittance is up to 6%.

(97) It is thus possible to reduce a discernible difference between the colors perceived by the human eyes and the colors of the image to be picked up and reproduced. In other words, it is possible to prevent degradation in images due to the fact that a color of short wavelength less likely to be perceived through the human sense of sight can be readily seen by the human eyes.

(98) When the ratio of the 400 nm wavelength transmittance is greater than 6%, the short wavelength region less likely to be perceived by the human eyes would be reproduced with perceivable wavelengths. When the ratio of the 420 nm wavelength transmittance is less than 15%, a wavelength region perceivable by the human eyes is less likely to be reproduced, putting colors in an ill-balanced state.

(99) Such means for limiting wavelengths can be more effective for image pickup systems using a complementary mosaic filter.

(100) In each of the aforesaid examples, coating is applied in such a way that, as shown in FIG. 24, the transmittance for 400 nm wavelength is 0%, the transmittance for 420 nm is 90%, and the transmittance for 440 nm peaks or reaches 100%.

(101) With the synergistic action of the aforesaid near-infrared sharp cut coat and that coating, the transmittance for 400 nm is set at 0%, the transmittance for 420 nm at 80%, the transmittance for 600 nm at 82%, and the transmittance for 700 nm at 2% with the transmittance for 450 nm wavelength peaking at 99%, thereby ensuring more faithful color reproduction.

(102) The low-pass filter LF is made up of three different filter elements stacked one upon another in the optical axis direction, each filter element having crystallographic axes in directions where, upon projected onto the image plane, the azimuth angle is horizontal (=0) and 45 therefrom. Three such filter elements are mutually displaced by a m in the horizontal direction and by SQRT()a in the 45 direction for the purpose of moir control, wherein SQRT means a square root as already mentioned.

(103) The image pickup plane I of a CCD is provided thereon with a complementary mosaic filter wherein, as' shown in FIG. 25, color filter elements of four colors, cyan, magenta, yellow and green are arranged in a mosaic fashion corresponding to image pickup pixels. More specifically, these four different color filter elements, used in almost equal numbers, are arranged in such a mosaic fashion that neighboring pixels do not correspond to the same type of color filter elements, thereby ensuring more faithful color reproduction.

(104) To be more specific, the complementary mosaic filter is composed of at least four different color filter elements, as shown in FIG. 25, which should preferably have such characteristics as given below.

(105) Each green color filter element G has a spectral strength peak at a wavelength Gp, each yellow filter element Ye has a spectral strength peak at a wavelength Y.sub.P, each cyan filter element C has a spectral strength peak at, a wavelength C.sub.P, and each magenta filter element M has spectral strength peaks at wavelengths M.sub.P1 and M.sub.P2, and these wavelengths satisfy the following conditions. 510 nm<G.sub.P<540 nm 5 nm<Y.sub.PG.sub.P<35 nm 100 nm<C.sub.PG.sub.P<5 nm 430 nm<M.sub.P1<480 nm 580 nm<M.sub.P2<640 nm

(106) To ensure higher color reproducibility, it is preferred that the green, yellow and cyan filter elements have a strength of at least 80% at 530 nm wavelength with respect to their respective spectral strength peaks, and the magenta filter elements have a strength of 10% to 50% at 530 nm wavelength with their spectral strength peak.

(107) One example of the wavelength characteristics in the aforesaid respective examples is shown in FIG. 26. The green filter element G has a spectral strength peak at 525 nm. The yellow filter element Ye has a spectral strength peak at 555 nm. The cyan filter element C has a spectral strength peak at 510 rm. The magenta filter element M has peaks at 445 nm and 620 nm. At 530 nm, the respective color filter elements have, with respect to their respective spectral strength peaks, strengths of 99% for G, 95% for Ye, 97% for C and 38% for M.

(108) For such a complementary filter, such signal processing as mentioned below is electrically carried out by means of a controller (not shown) (or a controller used with digital cameras).

(110) In this regard, it is noted that the aforesaid near-infrared sharp cut coat may be located anywhere on the optical path, and that the number of low-pass filters F may be either two as mentioned above or one.

(111) One typical detailed aperture stop portion in each example is shown in FIG. 27. At the stop position on the optical axis between the first lens group G1 and the second lens group G2 forming part of the image pickup optical System, there is located a turret 10 capable of making five-stage brightness adjustments at 0, 1, 2, 3 and 4 stages. The turret 10 is provided with a 0 stage adjustment opening 1A having a fixed circular aperture shape of about 4 mm in diameter (which has a 550 nm wavelength transmittance of 100%), a 1 stage correction opening 1B having an aperture area about half that of the opening 1A and a fixed aperture shape and comprising a transparent plane-parallel plate (having a 550 nm wavelength transmittance of 99%) and 2, 3, 4 stage correction openings 1C, 1D and 1E provided with ND filters having a 550 nm wavelength transmittance of 50%, 25% and 13%, respectively.

(112) The turret 10 is rotated around its rotating shaft 11 to locate any one of the openings at the stop position for light quantity adjustments.

(113) In the opening, there is also located an ND filter designed to have a 550 nm wavelength transmittance of less than 80% when the effective F-number or F.sub.no is F.sub.no>a/0.4 m. More specifically in Example 1, it is when the effective F-number at the 2 stage is 9.0 upon stop-in (the 0 stage) that the effective F-number at the telephoto end meets the aforesaid formula. The then opening is 1C, so that any image degradation due to diffraction phenomena by the stop is suppressed.

(114) As shown, a turret 10 of FIG. 28(a) may be used in place of the turret of FIG. 27. This turret 10 is capable of making five-stage brightness adjustments at 0, 1, 2, 3 and 4 stages, and located at an aperture stop position on the optical axis between the first lens group G1 and the second lens group G2 forming part of the image pickup optical system. The turret 10 is provided with a 0-stage adjustment opening 1A having a circular fixed aperture shape of about 4 mm in diameter, a 1 stage correction opening 1B having an aperture area about half that of the opening 1A and a fixed aperture shape, and 2, 3 and 4 stage correction openings 1C, 1D and 1E having a decreasing area in this order. The turret 10 is rotated around its rotating shaft 11 to locate any one of the openings at the stop position for light quantity adjustments.

(115) A plurality of such openings 1A to 1D are each provided with an optical low-pass filter having different spatial frequency characteristics. As shown in FIG. 28(b), the arrangement is such that the smaller the aperture diameter, the higher the spatial frequency characteristics of the optical filter, thereby reducing any image degradation due to diffraction phenomena by stop-down. The respective curves in FIG. 28(b) show the spatial frequency characteristics of the low-pass filters alone. In this regard, it is noted that the characteristics of the openings inclusive of diffractions by the stops are all equally determined.

(116) The electronic image pickup system constructed as described above may be applied to phototaking systems where object images formed through image-formation optical systems such as zoom lenses are received at image pickup devices such as CCDs or silver salt films, especially, digital cameras or video cameras as well as PCs and telephone sets which are typical information processors, in particular, easy-to-carry cellular phones. Given below are some such embodiments.

(117) FIGS. 29 to 31 are conceptual illustrations of a phototaking optical system 41 for digital cameras, in which the image-formation optical system of the invention is incorporated. FIG. 29 is a front perspective view of the outside shape of a digital camera 40, and FIG. 30 is a rear perspective view of the same. FIG. 31 is a sectional view of the construction of the digital camera 40. In this embodiment, the digital camera 40 comprises a phototaking optical system 41 including a phototaking, optical path 42, a finder optical system 43 including a finder optical path 44, a shutter 45, a flash 46, a liquid crystal monitor 47 and so on. As the shutter 45 mounted on the upper portion of the camera 40 is pressed down, phototaking takes place through the phototaking optical system 41, for instance, the optical path bending zoom optical system according to Example 2. An object image formed by the phototaking optical system 41 is formed on the image pickup plane of a CCD 49 via a near-infrared cut filter IF and an optical low-pass filter. The object image received at CCD 49 is displayed as an electronic image on the liquid crystal monitor 47 via processing means 51, which monitor is mounted on the back of the camera. This processing means 51 is connected with recording means 52 in which the phototaken electronic image may be recorded. It is here noted that the recording means 52 may be provided separately from the processing means 51 or, alternatively, it may be constructed in such a way that images are electronically recorded and written therein by means of floppy discs, memory cards, MOs or the like. This camera may also be constructed in the form of a silver salt camera using a silver salt camera in place of CCD 49.

(118) Moreover, a finder objective optical system 53 is located on the finder optical path 44. An object image formed by the finder objective optical path 53 is in turn formed on the field frame 57 of a Porro prism 55 that is an image erecting member. In the rear of the Porro prism 55 there is located an eyepiece optical system 59 for guiding an erected image into the eyeball E of an observer. It is here noted that cover members 50 are provided on the entrance sides of the phototaking optical system 41 and finder objective optical system 53 as well as on the exit side of the eyepiece optical system 59.

(119) With the thus constructed digital camera 40, it is possible to achieve high performance and cost reductions, because the phototaking optical system 41 is constructed of a fast zoom lens having a high zoom ratio at the wide-angle end with satisfactory aberrations and a back focus large enough to receive a filter, etc. therein.

(120) In the embodiment of FIG. 31, plane-parallel plates are used as the cover members 50; however, it is acceptable to use powered lenses.

(121) FIGS. 32 to 34 illustrates a personal computer that is one embodiment of information processors in which the image-formation optical system of the invention is built in the form of an objective optical system. FIG. 32 is a front perspective view of a personal computer or PC 300 in an uncovered state, FIG. 34 is a sectional view of a phototaking optical system 303 in PC 300, and FIG. 34 is a side view of FIG. 32. As shown in FIGS. 32 to 34, PC 300 comprises a keyboard 301 for allowing an operator to enter information therein from outside, information processing and recording means (not illustrated), a monitor 302 for displaying the information to the operator, and a phototaking optical system 303 for phototaking an image of the operator per se and nearby images. The monitor 302 used herein may be a transmission type liquid crystal display illuminated from its back side by means of a backlight (not shown), a reflection type liquid crystal display designed to reflect light from its front side for display purposes, a CRT display or the like. As shown, the phototaking optical system 303 is built in the right upper portion of the monitor 302; however, it may be located at any desired position, for instance, around the monitor 302 or the keyboard 301.

(122) This phototaking optical system 303 comprises an objective lens 112 mounted on a phototaking optical path 304 and formed of the optical path-bending zoom optical system of the invention (roughly shown) and an image pickup chip 162 for receiving images, which are built in PC 300.

(123) In this embodiment, a low-pass filter LF is additionally applied onto the image pickup chip 162 to form a one-piece unit 160 that can be mounted at the rear end of the lens barrel 113 of the objective lens 112 in one-touch snap operation. Thus, any centering or inter-surface adjustment for the objective lens 112 and image pickup chip 162 can be dispensed with, and so smooth assembly is achieved. Further, the lens barrel 113 is provided at the other end with a cover glass 114 for protection of the objective lens 112. It is here noted that the zoom lens drive mechanism in the lens barrel 113 is not shown.

(124) An object image received at the image pickup chip 162 is entered into the processing means of PC 300 via a terminal 166 and displayed as an electronic image on the monitor 302. As an example, an image 305 phototaken of the operator is shown in FIG. 32. The image 305 may be displayed on a personal computer on the other end of the line by way of processing means and the Internet or a telephone.

(125) FIG. 35 is illustrative of a telephone set, especially a convenient-to-carry cellular phone that is one exemplary information processor in which the image-formation optical system of the invention is built as a phototaking optical system. FIGS. 35(a) and 35(b) are a front view and a side view of a cellular phone 400, and FIG. 35(c) is a sectional view of a phototaking optical system 405. As shown in FIGS. 35(a) to 35(c), the cellular phone 400 comprises a microphone 401 through which the voice of an operator is entered as information, a speaker 402 through which the voice of a person on the other end of the like is produced, an input dial 403 through which the information is entered by the operator, a monitor 404 for displaying images phototaken of the operator per se, the person on the other end of the line and so on as well as information such as telephone numbers, a phototaking optical system 405, an antenna 406 for transmission and reception of radio waves for communications, and processing means (not shown) for processing image information, communications information, input signals, etc. Here a liquid crystal display is used for the monitor 404. How the respective devices are arranged is not particularly limited to the arrangement shown in FIG. 41. This phototaking optical system 405 comprises an objective lens 112 mounted on a phototaking optical path 407 and formed of the optical path-bending zoom optical system of the invention (roughly shown) and an image pickup chip 162 for receiving object images, which are built in the cellular phone 400.

(126) In this embodiment, a low-pass filter LF is additionally applied onto the image pickup chip 162 to form a one-piece unit 160 that can be mounted at the rear end of the lens barrel 113 of the objective lens 112 in one-touch snap operation. Thus, any centering or inter-surface adjustment for the objective lens 112 and image pickup chip 162 can be dispensed with, and so smooth assembly is achieved. Further, the lens barrel 113 is provided at the other end (not shown) with a cover glass 114 for protection of the objective lens 112. It is here noted that the zoom lens drive mechanism in the lens barrel 113, etc. are not shown.

(127) An object image received at the image pickup chip 162 is entered into processing means (not shown) via a terminal 166, so that the image is displayed as an electronic image on the monitor 404 and/or a monitor on the other end of the line. To transmit the image to the person on the other end, the signal processing means has a signal processing function of converting information on the object image received at the image pickup chip 162 to transmittable signals.

(128) As can be appreciated from the foregoing explanation, the present invention can provide a zoom lens that is received in a lens mount with smaller thickness and efficiency, has high magnifications and is excellent in image-formation capability even on rear focusing, and enables video cameras or digital cameras to be thoroughly slimmed down.

Electronic image pickup system

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G02B13/006

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H04N23/55

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G02B15/145123

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Abstract

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