Zoom objective lens

Abstract

The invention relates to a zoom objective lens with continuously adjustable magnification, comprising five lens groups, where the first lens group, the second lens group and the fifth lens group are fixed in relation to an object. The third lens group and the fourth lens group are axially displaceable. The following conditions apply to the lens: the variable air gap between the second lens group and the third lens group decreases or has a turning point with a transition from a low to a high magnification , the refractive power of the second, third and fifth lens groups is positive and the refractive power of the fourth lens group is negative.

Claims

1. A zoom objective lens with continuously adjustable magnification , comprising five lens groups, the first lens group, the second lens group and the fifth lens group being fixed in relation to an object and the third lens group and the fourth lens group being axially displaceable, in which the following conditions apply: a variable air gap between the second lens group and the third lens group decreases or has a turning point with a transition from a low to a high magnification , the refractive power of the second, third and fifth lens groups is positive and the refractive power of the fourth lens group is negative, wherein the first lens group is a single meniscus lens, wherein the second lens group consists of a maximum of two individual lenses, each having a positive refractive power, and a cemented lens component consisting of a maximum of three lenses, wherein the third lens group has either two individual lenses or a dual cemented lens component, wherein the fourth lens group consists of either a dual cemented lens component or a dual cemented lens component and an individual lens, wherein the dual cemented lens component has a meniscus lens, the centers of curvature of which lie on the object side, and wherein the fifth lens group is a dual cemented lens component, in which the biconvex lens lies on the image side.

2. The zoom objective lens according to claim 1, with a parfocal length of 60 mm and a structural length of 63.56 mm, the parfocal length being the length from the object plane to the objective lens mounting surface in front of a back stop, and the structural length being defined as the length from the object plane to the back stop.

3. The zoom objective lens according to claim 1, characterized in that, for displacing the third lens group and the fourth lens group, two adjustment elements are provided, which are actuated manually or by a motorized mechanism, in each case by means of a correcting ring.

4. The zoom objective lens according to claim 1, characterized in that the lenses have rims for the purpose of delimiting the beam bundle.

5. The zoom objective lens according to claim 1, characterized in that no aperture with an adjustable diameter for adjusting the magnification is provided.

6. A zoom objective lens with continuously adjustable magnification , comprising five lens groups, the first lens group, the second lens group and the fifth lens group being fixed in relation to an object and the third lens group and the fourth lens group being axially displaceable, in which the following conditions apply: a variable air gap between the second lens group and the third lens group decreases or has a turning point with a transition from a low to a high magnification , the refractive power of the second, third and fifth lens groups is positive and the refractive power of the fourth lens group is negative, wherein the first lens group is a cemented lens component, in which a front lens of the first lens group has a flat surface oriented toward the object side, wherein the second lens group consists of a maximum of two individual lenses, each having a positive refractive power, and a cemented lens component consisting of a maximum of three lenses, wherein the third lens group has either two individual lenses or a dual cemented lens component, wherein the fourth lens group consists of either a dual cemented lens component or a dual cemented lens component and an individual lens, wherein the dual cemented lens component has a meniscus lens, the centers of curvature of which lie on the object side, and the fifth lens group is a dual cemented lens component, in which the biconvex lens lies on the image side.

7. The zoom objective lens according to claim 6, with a parfocal length of 60 mm and a structural length of 63.56 mm, the parfocal length being the length from the object plane to the objective lens mounting surface in front of a back stop, and the structural length being defined as the length from the object plane to the back stop.

8. The zoom objective lens according to claim 6, characterized in that, for displacing the third lens group and the fourth lens group, two adjustment elements are provided, which are actuated manually or by a motorized mechanism, in each case by means of a correcting ring.

9. The zoom objective lens according to claim 6, characterized in that the lenses have rims for the purpose of delimiting the beam bundle.

10. The zoom objective lens according to claim 6, characterized in that no aperture with an adjustable diameter for adjusting the magnification is provided.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the zoom objective lens according to the invention will be specified in greater detail in reference to embodiment examples. The appended drawings show:

(2) FIG. 1: a schematic representation of a first embodiment example of the zoom objective lens for a magnification of 5 to 20,

(3) FIG. 2: a schematic representation of a second embodiment example of the zoom objective lens for a magnification of 10 to 40,

(4) FIG. 3: a schematic representation of a third embodiment example of the zoom objective lens for a magnification of 10 to 40,

(5) FIG. 4: a schematic representation of a fourth embodiment example of the zoom objective lens for a magnification of 10 to 40,

(6) FIG. 5: a graphic representation of longitudinal aberrations as a function of aperture for four wavelengths, in each case for minimum and maximum magnification, field curvature, astigmatism and distortion, according to the first embodiment,

(7) FIG. 6: a graphic representation of longitudinal aberrations as a function of aperture for four wavelengths, in each case for minimum and maximum magnification, field curvature, astigmatism and distortion, according to the second embodiment,

(8) FIG. 7: a graphic representation of longitudinal aberrations as a function of aperture for four wavelengths, in each case for minimum and maximum magnification, field curvature, astigmatism and distortion, according to the third embodiment, and

(9) FIG. 8: a graphic representation of longitudinal aberrations as a function of aperture for four wavelengths, in each case for minimum and maximum magnification, field curvature, astigmatism and distortion, according to the fourth embodiment.

(10) The present disclosure is susceptible of various modifications and alternative forms, and some representative embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the inventive aspects are not limited to the particular forms illustrated in the drawings. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.

DETAILED DESCRIPTION OF ILLUSTRATED EXAMPLES

(11) FIG. 1 shows a schematic representation of a first embodiment of the zoom objective lens for magnifications of 5 (minimum), 10 (medium) and 20 (maximum), comprising, coming from the object side Obj, the lens groups G1, G2, G3, G4 and G5, wherein the first lens group G1, the second lens group G2, and the fifth lens group G5 are fixed in relation to the object plane Obj, and the third lens group G3 and the fourth lens group G4 are axially displaceable and are characterized by variable air gaps A1, A2 and A3. The figure also shows surfaces FL11 to FL19 and radii r1 to r19 of lenses L1 to L10, and the thicknesses thereof, and air gaps d1 to d18. The variable air gap L1v=A1, designated as L1v, between lens groups G2 and G3 decreases with a transition from a low to a high magnification.

(12) The first lens group G1 of the zoom objective lens shown in this embodiment example, which is used without immersion, consists of a single meniscus lens L1. The refractive power of each of lens groups G2, G3 and G5 is positive, whereas the refractive power of lens group G4 is negative.

(13) Lens group G2 consists of at least one single lens L4 with positive refractive power and a cemented lens component consisting of at least two lenses L2 and L3.

(14) Lens group G3 comprises two lenses L5 and L6, which are either separate or cemented, whereas lens group G4 consists of a dual cemented lens component consisting of lenses L7 and L8, in which the meniscus lens L7 and both centers of curvature thereof are on the objective side Obj. Lens group G5 is a dual cemented lens component comprising lenses L9 and L10, in which biconvex lens L10 is located on the image side.

(15) The first embodiment of the zoom objective lens for magnifications of 5 to 20 with numerical apertures NA of 0.18 (at magnification 5) and 0.25 (at magnification 20) is characterized by the design data shown in the following table, in which radii r1 to r19 and the thicknesses, or air gaps d1 to d18, or the variable air gaps A1, A2 and A3 are indicated in mm, while n.sub.e is the refractive index and v.sub.e is the Abbe number,

(16) TABLE-US-00001 Surface Number Radius Thickness FL1-FL19 r1-r19 d1-d18 n.sub.e v.sub.e 1 flat 0.170 1.526 54.3 2 flat 6.000 3 6.7653 5.400 1.808 46.3 4 8.4532 2.636 5 175.5037 2.571 1.530 76.6 6 14.5588 1.200 1.658 39.5 7 38.5031 0.800 8 129.2733 2.000 1.530 76.6 9 17.1705 A1 10 29.1381 2.900 1.597 67.4 11 7.3667 1.200 1.617 44.3 12 24.3758 A2 13 15.6934 2.000 1.813 25.2 14 8.0534 1.300 1.716 53.7 15 28.5432 A3 16 783.1668 1.500 1.678 32.0 17 29.4250 4.500 1.489 70.2 18 16.6791 0.200 19 flat

(17) and with an achromatically corrected tube having a focal length of 195 mm, which is known per se.

(18) With an entry pupil set to infinity and a visual field index of 23, variable air gaps A1, A2 and A3 are characterized by the following variables:

(19) TABLE-US-00002 NA A1 A2 A3 5x 0.18 15.327 0.800 13.056 7.5x 0.20 9.613 8.862 10.707 10x 0.23 4.401 15.069 9.712 15x 0.23 2.852 21.831 4.499 20x 0.25 0.350 27.432 1.400

(20) wherein the delimiting surface FL12 has a diameter of 8.50 mm.

(21) FIG. 2 shows a schematic representation of a second embodiment of the zoom objective lens for magnifications of 10 (minimum), 20 (medium) and 40 (maximum), comprising, coming from the object side Obj, lens groups G1, G2, G3, G4 and G5, wherein, the first lens group G1, the second lens group G2, and the fifth lens group G5 are fixed in relation to the object plane, and the third lens group G3 and fourth lens group G4 are axially displaceable and are characterized by variable air gaps A1, A2 and A3. The figure further shows surfaces FL1 to FL23 and radii r1 to r23 of lenses L1 to L12 and the thicknesses or air gaps d1 to d22 thereof. In this case, the variable air gap L1v=A1, designated as L1v, between lens groups G2 and G3 has a turning point, not shown in greater detail, for a transition from a low to a high magnification.

(22) First lens group G1 of the zoom objective lens shown in this embodiment, which is likewise used without immersion, consists of a single meniscus lens L1 like in the first embodiment. The refractive power of each of lens groups G2. G3 and G5 is positive, whereas the refractive power of lens group G4 is negative.

(23) Lens group G2 consists of two individual lenses L2 and L3 and a triple cemented lens component consisting of lenses L4, L5 and L6, while Lens group G3 comprises two lenses L7 and L8, which are either separate, as shown in this embodiment, or alternatively cemented.

(24) Lens group G4 is a dual cemented lens component consisting of lenses L9 and L10, in which the meniscus lens L9 and both of the centers of curvature thereof are located on the object side Obj.

(25) Lens group G5 is a dual cemented lens component comprising lenses L11 and L12, in which biconvex lens L12 is located on the image side.

(26) The second embodiment of the zoom objective lens for magnifications of 10 to 40 with numerical apertures NA of 0.3 (at 10 magnification) and of 0.6 (at 40 magnification) is characterized by the design data showing in the following table, in which radii r1 to r23 and the thicknesses or air gaps d1 to d22 or the variable air gaps A1, A2 and A3 are given in mm, while n.sub.e is the refractive index and v.sub.e is the Abbe number:

(27) TABLE-US-00003 Surface Number Radius Thickness FL1-FL23 r1-r23 d1-d22 n.sub.e v.sub.e 1 Flat 0.170 1.526 54.3 2 Flat 2.214 3 3.2550 3.680 1.758 52.1 4 5.1580 0.512 5 18.3030 2.500 1.498 81.1 6 14.0240 0.500 7 50.1187 1.800 1.530 76.6 8 12.9580 0.499 9 133.3541 1.200 1.658 39.5 10 9.3070 5.600 1.440 94.5 11 6.1313 2.150 1.658 39.5 12 11.3030 A1 13 9.0390 3.000 1.620 63.1 14 7.6060 2.000 15 19.6700 2.050 1.530 76.6 16 66.8362 A2 17 9.1730 1.650 1.624 36.1 18 5.0120 1.200 1.489 70.2 19 14.3310 A3 20 325.4810 1.200 1.624 36.1 21 27.5827 3.100 1.530 76.6 22 21.9103 0.300 23 Flat

(28) and further comprising an achromatically corrected tube having a focal length of 195 mm, which is known per se.

(29) With an entry pupil set to infinity and a visual field index of 22, the variable air gaps A1, A2 and A3 are characterized by the following variables:

(30) TABLE-US-00004 NA A1 A2 A3 10x 0.30 7.217 0.800 20.217 20x 0.45 0.500 13.258 14.477 30x 0.55 2.505 17.785 7.944 40x 0.60 7.570 19.864 0.800

(31) wherein the delimiting surfaces FL3, FL13, FL19 and FL23 have the following diameters:

(32) TABLE-US-00005 Surface Number Diameter FL3 3.04 FL13 12.60 FL19 5.44 FL23 14.60

(33) FIG. 3 shows a schematic illustration of a third embodiment of the zoom objective lens for magnifications of 10 (minimum), 20 (medium) and 40 (maximum) comprising, coming from the object side Obj, lens groups G1, G2, G3, G4 and G5, in which, the first lens group G1 the second lens group G2 and the fifth lens group G5 are fixed in relation to the object plane Obj and the third lens group G3 and the fourth lens group G4 are axially displaceable and are characterized by variable air gaps A1. A2 and A3, as described in the previous embodiments. The figure further shows surfaces FL1 to FL24 and radii r1 to r24 of lenses L1 to L14 and the thicknesses or air gaps d1 to d23 thereof. The variable air gap L1v=A1, designated as L1v, between lens groups G2 and G3, decreases with a transition from a low to a high magnification.

(34) First lens group G1 of the zoom objective lens is used with immersion, it consists of a cemented lens component comprising lenses L1, L2 and L3, wherein the front lens L1 has a flat surface on the object side Obj. The refractive power of each of lens groups G2, G3 and G5 is positive, whereas the refractive power of lens group G4 is negative.

(35) In this case, lens group G2 consists of an individual lens L4 and a triple cemented lens component L5, L6 and L7, whereas lens group G3 has two lenses L8 and L9, which are either cemented as shown or alternatively separate.

(36) Lens group G4 consists of an individual lens L10 and a dual cemented lens component, consisting of lenses L11 and L12, in which meniscus lens L11 and the two centers of curvature thereof are located on the object side Obj.

(37) Lens group G5 is a dual cemented lens component having lenses L13 and L14, in which biconvex lens L14 is located on the image side.

(38) The third embodiment example of the zoom objective lens, suited for magnifications of 10 to 40 with numerical apertures NA of 0.3 (at magnification 10) and 0.8 (at magnification 40) is characterized by design data shown in the following table, in which radii r1 to r24 and the thicknesses or air gaps d1 to d23, and the variable air gaps A1, A2 and A3 are indicated in mm, while n.sub.e is the refractive index and v.sub.e is the Abbe number:

(39) TABLE-US-00006 Surface Number Radius Thickness FL1-FL24 r1-r24 d1-d23 n.sub.e v.sub.e 1 Flat 0.170 1.526 54.3 2 Flat 1.300 1.334 55.9 3 Flat 1.100 1.489 70.2 4 1.4487 2.229 1.888 40.5 5 7.5654 2.400 1.620 63.1 6 4.3205 0.500 7 60.7020 2.650 1.530 76.6 8 8.2476 0.500 9 80.3925 1.200 1.617 44.3 10 13.0369 5.400 1.440 94.5 11 7.6168 1.400 1.617 44.3 12 16.7348 A1 13 23.5032 3.400 1.700 55.2 14 14.2452 1.100 1.617 44.3 15 92.0615 A2 16 104.7364 1.100 1.561 53.8 17 11.4708 1.500 18 5.9185 2.020 1.855 23.7 19 5.2823 1.100 1.617 44.3 20 12.8144 A3 21 1355.4370 1.200 1.607 37.8 22 16.6021 3.100 1.530 76.6 23 15.5387 0.300 24 Flat

(40) and further comprising an achromatically corrected tube having a focal length of 195 mm, which is known per se.

(41) With an entry pupil set to infinity and a vision field index of 20, variable air gaps A1, A2 and A3 are characterized by the following parameters:

(42) TABLE-US-00007 NA A1 A2 A3 10x 0.30 20.181 0.800 8.911 20x 0.52 6.300 17.244 6.342 30x 0.70 1.528 24.687 3.693 40x 0.80 0.500 28.524 0.800

(43) wherein delimiting surfaces FL3, FL15, FL20 and FL24 have the following diameters:

(44) TABLE-US-00008 Surface Number Diameter FL3 2.80 FL15 12.90 FL20 7.20 FL24 12.00

(45) FIG. 4 shows a schematic representation of a fourth embodiment of the zoom objective lens for magnifications of 10 (minimum), 20 (medium) and 40 (maximum), comprising, coming from the object side Obj, lens groups G1, G2, G3, G4 and G5, wherein the first lens group G1, the second lens group G2 and the fifth lens group G5 are fixed in relation to the object plane Obj and the third lens group G3 and fourth lens group G4 are axially displaceable and are characterized by variable air gaps A1. A2 and A3, as described in the previous embodiments. The figure further shows surfaces FL1 to FL23 and radii r1 to r23 of lenses L1 to L13, and the thicknesses or air gaps d1 to d22 thereof. The variable air gap L1v=A1, designated as L1v, between lens groups G2 and G3 decreases with a transition from a low to a high magnification.

(46) The first lens group G1 of the zoom objective lens shown in this embodiment, which is used with immersion, consists of a cemented lens component comprising lenses L1 and L2, in which front lens L1 has a flat surface on the object side Obj. The refractive power of each of lens groups G2, G3 and G5 is positive, whereas the refractive power of lens group G4 is negative.

(47) Lens group G2 consists of two individual lenses L3 and L4 and a triple cemented lens component, consisting of lenses L5, L6 and L7, whereas lens group G3 has two lenses L8 and L9, which are either cemented as shown, or are alternatively separate.

(48) Lens group G4 consists of a dual cemented lens component comprising lenses L10 and L11, in which the meniscus lens L10 and the two centers of curvature thereof are located on the object side Obj.

(49) Lens group G5 is a dual cemented lens component having lenses L12 and L13, in which biconvex lens L13 is located on the image side.

(50) The fourth embodiment of the zoom objective lens for magnifications of 10 to 40 with numerical apertures NA of 0.3 (at magnification 10) and 0.8 (at magnification 40) is characterized by the design data shown in the following table, in which radii r1 to r23 and the thicknesses or air gaps d1 to d22, and the variable air gaps A1, A2 and A3 are given in mm, whereas n.sub.e is the refractive index and v.sub.e is the Abbe number:

(51) TABLE-US-00009 Surface Number Radius Thickness FL1-FL23 r1-r23 d1-d22 n.sub.e v.sub.e 1 Flat 0.170 1.526 54.3 2 Flat 1.047 1.334 55.9 3 Flat 1.110 1.460 67.7 4 1.4130 6.010 1.888 40.5 5 5.9570 0.300 6 20.8340 2.130 1.594 68.0 7 10.7450 0.262 8 47.6566 2.900 1.594 68.0 9 16.4292 0.304 10 28.7996 1.200 1.561 53.8 11 9.7156 4.800 1.435 94.7 12 12.4080 1.100 1.607 37.8 13 20.8340 A1 14 20.2422 4.400 1.530 76.6 15 9.4424 1.200 1.617 44.3 16 23.5430 A2 17 11.7130 1.300 1.855 23.7 18 7.9440 1.200 1.561 53.8 19 20.8340 A3 20 115.4813 1.200 1.624 36.1 21 28.1840 2.900 1.498 81.2 22 15.9619 0.180 23 Flat

(52) and further comprising a tube corrected according to ICS (Infinity-Color-Corrected System) having a focal length of 164.5 mm.

(53) With an entry pupil set to infinity and a vision field index of 20, the variable air gaps A1, A2 and A3 are characterized by the following parameters:

(54) TABLE-US-00010 NA A1 A2 A3 10x 0.30 15.278 1.000 13.570 20x 0.48 6.664 14.753 8.431 30x 0.65 2.835 22.722 4.290 40x 0.80 0.500 28.547 0.800

(55) wherein delimiting surfaces FL3, FL6, FL17 and FL23 have the following diameters:

(56) TABLE-US-00011 Surface Number Diameter FL3 2.56 FL6 11.10 FL17 5.86 FL23 12.30

(57) FIG. 5 shows, for the zoom objective lens according to first embodiment, a representation of longitudinal aberrations in the exit pupil, as a function of the aperture for four wavelengths (0.480 nm, 0.546 nm, 0.644 nm and 0.436 nm), for the minimum magnification of 5 (image I) and the maximum magnification of 20 (image II). The field curvature and astigmatism for this zoom objective lens are also shown (images III and V).

(58) Images III and V depict the sagittal and tangential image curves for the four wavelengths, as a function of the image height Y (maximum 11 mm), for both the minimum and maximum magnifications. Here, S stands for the sagittal and T for the tangential image curves. The S and T image curves are always indicated in pairs, and therefore only the T image curves are identified in the graphs. The astigmatism is derived from the difference between the two image curves.

(59) The distortion (images IV and VI) as a function of the image height Y (maximum 11 mm) for the four different wavelengths is likewise shown for the minimum and maximum magnifications.

(60) FIG. 6 shows, for the zoom objective lens according to the second embodiment, a representation of longitudinal aberrations in the exit pupil as a function of the aperture for four wavelengths (0.644 nm, 0.546 nm, 0.480 nm and 0.436 nm), for the minimum magnification of 10 (image I) and the maximum magnification of 40 (image II). Also shown for this zoom objective lens are the field curvature and the astigmatism (images III and V). Images III and V each depict the sagittal and tangential image curves for the four wavelengths, as a function of the image height Y (maximum 11 mm), each for the minimum and maximum magnifications. Here, S stands for the sagittal image curve and T for the tangential image curve. The S and T image curves are always indicated in pairs, therefore only the T image curves are labeled in the graph. The astigmatism is derived from the difference between the two image curves. The distortion (images IV and VI) as a function of the image height Y (maximum 11 mm) for the four different wavelengths is likewise shown for the minimum and maximum magnifications.

(61) FIG. 7 shows, for the zoom objective lens according to the third embodiment, a representation of longitudinal aberrations in the exit pupil, as a function of the aperture for four wavelengths (0.644 nm, 0.546 nm, 0.480 nm and 0.436 nm), for the minimum magnification of 10 (image I) and the maximum magnification of 40 (image II) with a zoom objective lens according to embodiment example 3.

(62) Also shown for this zoom objective lens are the field curvature and the astigmatism (images III and V). Images III and V each depict the sagittal and tangential image curve for the four wavelengths, as a function of the image height Y (maximum 11 mm), in each case for the minimum and maximum magnifications. Here, S stands for the sagittal image curve and T for the tangential image curve. The S and T image curves are always indicated in pairs, therefore only the T image curves are labeled in the graphs. The astigmatism is derived from the difference between the two image curves. The distortion (images IV and VI) as a function of the image height Y (maximum 11 mm) for the four different wavelengths is likewise represented for the minimum and maximum magnifications.

(63) FIG. 8 shows, for the zoom objective lens according to the fourth embodiment, a representation of longitudinal aberrations in the exit pupil as a function of the aperture for four wavelengths (0.480 nm, 0.436 nm, 0.546 nm and 0.644 nm), for the minimum magnification of 10 (image I) and the maximum magnification of 40 (image II) with a zoom objective lens according to embodiment example 4. Also shown for this zoom objective lens are the field curvature and the astigmatism (images III and V). Images III and V each depict the sagittal and tangential image curves for the four wavelengths, as a function of the image height Y (maximum 11 mm), in each case for the minimum and maximum magnifications. Here, S stands for the sagittal image curve and T for the tangential image curve. The S and T image curves are always indicated in pairs, therefore only the T image curves are labeled in the graphs. The astigmatism is derived from the difference between the two image curves. The distortion (images IV and VI) as a function of the image height Y (maximum 11 mm) for the four different wavelengths is likewise shown for the minimum and maximum magnifications.

(64) The present disclosure is not limited to the precise construction and compositions disclosed herein; any and all modifications, changes, and variations apparent from the foregoing descriptions are within the spirit and scope of the disclosure as defined in the appended claims. Moreover, the present concepts expressly include any and all combinations and sub combinations of the preceding elements and aspects.