JP5836087B2 - Microscope relay optical system - Google Patents

Description

  The present invention relates to a microscope relay optical system, and more particularly to a microscope relay optical system that relays a primary image of a specimen to infinity.

  The microscope relay optical system is an optical system that relays the specimen image and the pupil of the objective lens, and is used, for example, for the purpose of adjusting the optical path length and securing the location of the pupil modulation element.

As a document disclosing a relay optical system whose main purpose is adjustment of the optical path length, for example, there is Patent Document 1.
Patent Document 1 discloses an image relay optical system that relays a primary image of a specimen formed by an objective lens and an imaging lens to form a secondary image near the eye point position. The image relay optical system disclosed in Patent Document 1 includes a front group and a rear group, and relays an image to infinity between the front group and the rear group. For this reason, the eye point position can be easily adjusted only by changing the interval between the front group and the rear group.

Further, as a document disclosing a relay optical system whose main purpose is to secure an arrangement place of a pupil modulation element, for example, there is Patent Document 2.
Patent Document 2 discloses a relay optical system that relays light from a primary image formed by an objective lens and an imaging lens to form a secondary image. The relay optical system disclosed in Patent Document 2 has a first relay lens and a second relay lens from the primary image side, a parallel light beam is formed between them, and an image of the exit pupil of the objective lens is formed therebetween. It is comprised so that. For this reason, the pupil modulation element can be arranged on the pupil conjugate plane between the first relay lens and the second relay lens.

JP-A-8-136811 JP 2009-122624 A

  By the way, an optical system composed of a plurality of lenses such as a relay optical system is generally designed so that desired optical performance can be obtained in a state where optical axes of a plurality of lenses constituting the optical system coincide with each other. Yes.

For this reason, the assembly of the optical system is based on a so-called frame centering configuration in which a centering operation for correcting the deviation of the optical axis of the lens (hereinafter referred to as eccentricity) is performed after the frame placing operation for dropping the lens into the lens frame. Usually done. This is because the optical axes of the plurality of lenses do not always coincide with each other only by the frame placing operation, and as a result, the optical system may not exhibit the desired optical performance.
However, if the deterioration of the optical performance against the decentration of the lens can be suppressed, the centering operation can be omitted and the assembly process of the optical system can be simplified.

  In view of the above circumstances, an object of the present invention is to provide a technique for a relay optical system for a microscope having excellent optical performance, in which deterioration of optical performance with respect to lens decentration is suppressed.

A first aspect of the present invention is a microscope relay optical system that relays a primary image of a specimen to infinity, and has a positive power composed of a first cemented lens in order from the primary image side. A first lens group having a negative meniscus lens having a convex surface facing the primary image, and a plano-concave lens having a flat surface facing the primary image. is the provide a third lens group having a negative power, and a second cemented lens, a fourth lens group having a positive power, a microscope relay optical system comprising.

  According to a second aspect of the present invention, the first cemented lens includes, in order from the primary image side, a biconvex lens and a negative meniscus lens having a concave surface facing the primary image side. The lens provides the microscope relay optical system according to the first aspect, which includes, in order from the primary image side, a biconcave lens and a biconvex lens.

A third aspect of the present invention is the microscope according to the second aspect that satisfies the following conditional expression when F is a focal length of the microscope relay optical system and f3G is a focal length of the third lens group. A relay optical system is provided.
−0.77 <f3G / F <−0.46

According to a fourth aspect of the present invention, when F is a focal length of the microscope relay optical system and f4G is a focal length of the fourth lens group, the second aspect or the third aspect satisfying the following conditional expression: A relay optical system for a microscope according to an aspect is provided.
0.43 <f4G / F <0.76

  According to a fifth aspect of the present invention, there is provided a microscope including an objective lens and the microscope relay optical system according to any one of the first to fourth aspects.

  According to a sixth aspect of the present invention, there is provided the microscope according to the fifth aspect, wherein a pupil conjugate position of the objective lens is disposed on any surface of the third lens group or the fourth lens group.

  ADVANTAGE OF THE INVENTION According to this invention, the technique of the relay optical system for microscopes which has the favorable optical performance which suppressed the deterioration of the optical performance with respect to eccentricity of a lens can be provided.

It is the figure which illustrated the composition of the microscope provided with the relay optical system for microscopes concerning Example 1 of the present invention. It is sectional drawing of the optical system of the microscope provided with the relay optical system for microscopes concerning Example 1 of this invention. FIG. 3 is an aberration diagram on an image plane of the optical system of the microscope exemplified in FIG. 2. 3 is a spot diagram on an image plane of an optical system of a microscope exemplified in FIG. 2. It is sectional drawing of the optical system of the microscope provided with the relay optical system for microscopes concerning Example 2 of this invention. FIG. 6 is an aberration diagram on an image plane of the optical system of the microscope exemplified in FIG. 5. 6 is a spot diagram on the image plane of the optical system of the microscope exemplified in FIG. 5. It is sectional drawing of the optical system of the microscope provided with the relay optical system for microscopes concerning Example 3 of this invention. FIG. 9 is an aberration diagram on an image plane of the optical system of the microscope illustrated in FIG. 8. FIG. 9 is a spot diagram on an image plane of the optical system of the microscope illustrated in FIG. 8.

FIG. 1 is a diagram illustrating a configuration of a microscope including the microscope relay optical system according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of an optical system of a microscope including the microscope relay optical system according to the first embodiment of the present invention.
First, the configuration and operation of the microscope and the optical system common to each embodiment will be described with reference to the microscope and the optical system according to the first embodiment illustrated in FIGS.

  As illustrated in FIG. 1, the microscope 100 is an inverted microscope that illuminates and observes a specimen with transmitted illumination. The microscope 100 includes a light source unit 10, a transmission column 20, and a capacitor 30 in order from the light emitting surface EP side to the sample surface SP side on the illumination optical path. The microscope 100 further includes an objective lens 40, an imaging lens 50, a prism group 60, a microscope relay optical system 1, and a prism group in order from the specimen surface SP side to the image plane side on the observation optical path. 70, an imaging lens 80, and a prism group 90.

FIG. 2 shows a detailed configuration of the optical system arranged on the image side of the objective lens 40 in the optical system of the microscope 100 illustrated in FIG.
The imaging lens 50 is a cemented lens of a biconvex lens 51 and a meniscus lens 52 having a concave surface facing the object side, and condenses parallel light incident from the object side (objective lens 40 side) on the primary image surface IP1. Thus, a primary image of the specimen is formed.

  The microscope relay optical system 1 is a microscope relay optical system that relays a primary image of a specimen formed by the imaging lens 50 to infinity, and has a first power having a positive power in order from the primary image side. It includes a lens group G1, a second lens group G2 having negative power, a third lens group G3 having negative power, and a fourth lens group G4 having positive power.

  The first lens group G1 includes, in order from the primary image side, a cemented lens CL1 (first cemented lens) including a biconvex lens L1 and a negative meniscus lens L2 having a concave surface facing the primary image side. The second lens group G2 includes a negative meniscus lens L3 having a convex surface directed toward the primary image side. The third lens group G3 is composed of a plano-concave lens L4 having a plane directed to the primary image side. The fourth lens group G4 includes, in order from the primary image side, a cemented lens CL2 (second cemented lens) including a biconcave lens L5 and a biconvex lens L6.

  The imaging lens 80 includes a meniscus lens 81 having a concave surface facing the image side, and a cemented lens composed of a biconvex lens 82 and a biconcave lens 83, and is parallel light incident from the object side formed by the microscope relay optical system 1. Is condensed on the secondary image plane IP2 to form a secondary image of the specimen.

  Note that a prism group 60 disposed between the imaging lens 50 and the primary image plane IP1, a prism group 70 disposed between the microscope relay optical system 1 and the imaging lens 80, and the imaging lens 80 and the secondary lens. The prism group 90 disposed between the image plane IP2 is composed of two prisms (prism 61 and prism 62, prism 71 and prism 72, prism 91 and prism 92) of the same material.

  In the microscope 100 configured as described above, the illumination light emitted from the light emitting surface EP in the light source unit 10 is irradiated onto the sample surface SP via the transmission column 20 and the capacitor 30. The light from the specimen surface SP irradiated with the illumination light is converted into parallel light by the objective lens 40 and enters the imaging lens 50. The imaging lens 50 condenses the incident parallel light on the primary image plane IP1 via the prism group 60 to form a primary image of the sample. The light from the primary image of the specimen on the primary image plane IP1 is converted into parallel light again by the microscope relay optical system 1 and enters the imaging lens 80. The imaging lens 80 condenses the parallel light incident through the prism group 70 on the secondary image plane IP2 through the prism group 90 to form a secondary image of the sample. Thereby, the user of the microscope can observe this secondary image via an eyepiece lens (not shown).

Next, main actions of each lens group constituting the microscope relay optical system 1 will be described.
In the microscope relay optical system 1, the first lens group G1 constituted by the cemented lens CL1 mainly controls the chromatic aberration of magnification, and the second lens group G2 constituted by the negative meniscus lens mainly suppresses the Petzval sum. Thus, the curvature of field is controlled, and the third lens group G3 composed of plano-concave lenses and the fourth lens group G4 composed of the cemented lens CL2 mainly control the image position and magnification. The fourth lens group G4 also plays a role of controlling spherical aberration.

  If the first lens group G1 and the second lens group G2 are defined as the front group, and the third lens group G3 and the fourth lens group G3 are defined as the rear group, in the microscope relay optical system 1, the front group mainly has the pupil. The rear group is responsible for controlling the image.

  In addition to the concave surface of the second lens group, the microscope relay optical system 1 disperses so-called concave power by having concave surfaces in contact with air in the third lens group and the fourth lens group, respectively. Thereby, the power of both the third lens group G3 and the fourth lens group G4 is kept relatively small while the Petzval sum is kept small and the curvature of field is satisfactorily corrected.

  Accordingly, since the microscope relay optical system 1 can correct aberrations satisfactorily while suppressing the power of each lens group, the optical performance deterioration with respect to the decentration of the lens is suppressed, and good optical performance is realized. be able to.

In addition to the above-described configuration, the microscope relay optical system 1 preferably satisfies the following conditional expressions. Here, F is the focal length of the microscope relay optical system 1, f3G is the focal length of the third lens group G3, and f4G is the focal length of the fourth lens group G4.
−0.77 <f3G / F <−0.46 (1)
0.43 <f4G / F <0.76 (2)

Conditional expression (1) is defined by the ratio of the focal length of the third lens group G3 to the focal length of the microscope relay optical system 1, and represents the degree of divergence of the light flux in the third lens group.
If the lower limit value of conditional expression (1) is not reached, the power of the third lens group G3 is relatively weak, so that it is possible to suppress degradation of optical performance against lens decentration. However, in order to satisfactorily correct aberrations, it is necessary to increase the distance between the third lens group G3 and the fourth lens group G4, and therefore, within the limited total length allowed for the microscope relay optical system 1. This makes it difficult to correct aberrations satisfactorily. On the other hand, if the upper limit of conditional expression (1) is exceeded, the power of the third lens group G3 becomes relatively strong, and the light beam is refracted at a steep angle. For this reason, the optical performance is greatly deteriorated with respect to the eccentricity of the lens.

Conditional expression (2) is defined by the ratio of the focal length of the fourth lens group G4 to the focal length of the microscope relay optical system 1, and represents the degree of divergence of the light flux in the fourth lens group.
When the lower limit value of conditional expression (2) is not reached, the power of the fourth lens group G4 becomes relatively strong, and the light beam is refracted at a steep angle. For this reason, the optical performance is greatly deteriorated with respect to the eccentricity of the lens. On the other hand, if the upper limit value of conditional expression (2) is exceeded, the power of the fourth lens group G4 is relatively weak, so that it is possible to suppress degradation of optical performance against lens decentration. However, since the power is insufficient, it is difficult to correct aberrations satisfactorily.

Note that, as shown by the conditional expressions (1) and (2), the microscope relay optical system 1 has substantially the same negative power of the third lens group G3 and positive power of the fourth lens group G4. It is desirable to make it about. As a result, the power of one of the third lens group G3 and the fourth lens group G4 is prevented from becoming excessively strong, so that the degree of deterioration in performance with respect to the eccentricity of the microscope relay optical system 1 as a whole can be kept low. it can.
In addition, it is effective for the present invention to satisfy one of conditional expression (1) and conditional expression (2).

  The microscope relay optical system 1 is preferably designed so that the pupil conjugate plane of the objective lens 40 is positioned on the optical surface of the microscope relay optical system 1. For example, the pupil conjugate plane is on one of the optical surfaces of the third lens group G3 when the stage of the microscope 100 is in the reference state, and on one of the optical surfaces of the fourth lens group G4 when it is in the stage-up state. It may be designed to be located. Thus, by forming a phase film on the optical surface of the microscope relay optical system 1, the lens of the microscope relay optical system 1 can function as a pupil modulation element.

Hereinafter, a relay optical system for a microscope and a microscope according to each example will be described.
Note that the microscope according to Example 1 is the microscope 100 illustrated in FIG. 1 and is as described above. Further, the microscope 200 according to the second embodiment and the microscope 300 according to the third embodiment are different in that the relay optical system for the microscope is different for each embodiment and the distance from the final surface of the prism group 90 to the secondary image plane IP2 is different for each embodiment. The microscope 100 is the same as the microscope 100 according to the first embodiment except for the differences. Therefore, in each Example, detailed description about a microscope is abbreviate | omitted.

  FIG. 1 is a diagram illustrating the configuration of a microscope including a microscope relay optical system according to the present embodiment. FIG. 2 is a cross-sectional view of an optical system of a microscope provided with the microscope relay optical system according to the present embodiment. The microscope relay optical system 1 illustrated in FIG. 2 is a microscope relay optical system that relays the primary image of the specimen formed by the imaging lens 50 to infinity, and the lens configuration thereof is as described above. It is.

Hereinafter, various data according to the present embodiment will be described.
The focal length F of the microscope relay optical system 1, the focal length f3G of the third lens group G3, the focal length f4G of the fourth lens group G4, the image-side numerical aperture NAI of the microscope relay optical system 1, and the image height Each FIY is as follows.
F = 180.23 mm, f3G = −127.33 mm, f4G = 123.14 mm,
NAI = 0.04, FIY = 11mm

The lens data of the optical system of the microscope 100 according to this embodiment illustrated in FIG. 2 is as follows.
srd nd vd
1 INF 177.5
2 178.4248 6.1 1.48749 70.23
3 -63.4109 4 1.7185 33.52
4 -111.259 2.0047
5 INF 18 1.51633 64.14
6 INF 18 1.51633 64.14
7 INF 153.3395
8 INF 87.201
9 109.6828 5.2 1.6516 58.55
10 -60.1401 3.8 1.6727 32.1
11 -250.569 6.2577
12 27.0219 13.7 1.56883 56.36
13 19.4164 52.0723
14 INF 2.5 1.48749 70.23
15 62.0738 43
16 -292.5594 3 1.51742 52.43
17 72.321 3.5 1.497 81.54
18 -49.2626 2.93
19 INF 25 1.51633 64.14
20 INF 25 1.51633 64.14
21 INF 37.367
22 54.9349 3 1.48749 70.2
23 278.88 0.3359
24 32.9209 6 1.72342 37.9
25 -90.9349 2.6 1.7185 33.5
26 25.9272 62.726
27 INF 26 1.56883 56.36
28 INF 4
29 INF 65 1.56883 56.36
30 INF 25.94

  Here, s is a surface number, r is a radius of curvature (mm), d is a surface interval (mm), nd is a refractive index with respect to the d line, and vd is an Abbe number with respect to the d line. The surface number s1 indicates the pupil position of the objective lens 40 illustrated in FIG. Surface numbers s2 to s4 indicate optical surfaces of the imaging lens 50. Surface numbers s5 to s7 indicate optical surfaces of the prism group 60. The surface number s8 indicates the primary image surface IP1. Surface numbers s9 to s18 indicate optical surfaces of the microscope relay optical system 1. Surface numbers s19 to s21 indicate optical surfaces of the prism group 70. Surface numbers s22 to s26 indicate optical surfaces of the imaging lens 80. Surface numbers s27 to s30 indicate optical surfaces of the prism group 90. The surface interval d30 indicates the interval between the final surface (surface number s30) of the prism group 70 and the secondary image surface IP2.

The microscope relay optical system 1 according to the present example satisfies the conditional expressions (1) and (2) as represented by the following expressions (A1) and (A2). Expressions (A1) and (A2) correspond to conditional expressions (1) and (2), respectively.
f3G / F = −0.706 (A1)
f4G / F = 0.683 (A2)

  FIG. 3 is an aberration diagram of the optical system of the microscope illustrated in FIG. 2, and shows aberrations on the secondary image plane IP2 when the axial light beam enters the imaging lens 50 as parallel light parallel to the optical axis. ing. 3A is a spherical aberration diagram, FIG. 3B is an astigmatism diagram, and FIGS. 3C and 3D are an image height ratio of 0.5 and an image height ratio of 0. 0, respectively. FIG. 3E is a coma aberration diagram at position 8, FIG. 3E is a chromatic aberration of magnification, and FIG. 3F is a distortion aberration. It is shown that each aberration is satisfactorily corrected in any state. In the figure, “M” indicates a meridional component and “S” indicates a sagittal component.

  FIG. 4 is a spot diagram of the optical system of the microscope illustrated in FIG. 2, and is a spot diagram at a position of an image height ratio of 0.8 on the secondary image plane IP2. FIG. 4A is a spot diagram in the non-eccentric state. FIGS. 4B, 4C, 4D, and 4E are the first lens group G1 and the second lens group, respectively. It is a spot diagram in a state where G2, the third lens group G3, and the fourth lens group G4 are decentered by shifting by 0.1 mm in a direction orthogonal to the optical axis.

FIG. 5 is a cross-sectional view of an optical system of a microscope provided with the microscope relay optical system according to the present embodiment. The microscope relay optical system 2 illustrated in FIG. 5 is a microscope relay optical system that relays the primary image of the specimen formed by the imaging lens 50 to infinity, and the lens configuration thereof is shown in FIG. This is the same as the microscope relay optical system 1 according to Example 1 illustrated.
Hereinafter, various data according to the present embodiment will be described.

The focal length F of the microscope relay optical system 2, the focal length f3G of the third lens group G3, the focal length f4G of the fourth lens group G4, the image-side numerical aperture NAI of the microscope relay optical system 2, and the image height Each FIY is as follows.
F = 180.4 mm, f3G = −85.5 mm, f4G = 80 mm,
NAI = 0.04, FIY = 11mm

The lens data of the optical system of the microscope 200 according to this embodiment illustrated in FIG. 5 is as follows.
srd nd vd
1 INF 177.5
2 178.4248 6.1 1.48749 70.23
3 -63.4109 4 1.7185 33.52
4 -111.259 2.0047
5 INF 18 1.51633 64.14
6 INF 18 1.51633 64.14
7 INF 153.3395
8 INF 87.201
9 743.6761 5.2 1.6516 58.55
10 -41.432 3.8 1.6727 32.1
11 -80.2437 50.8917
12 26.0066 13.7 1.56883 56.36
13 15.9765 25.1856
14 INF 2.5 1.48749 70.23
15 41.6584 25.2527
16 -117.96 3 1.51742 52.43
17 62.4083 3.5 1.497 81.54
18 -29.437 2.93
19 INF 25 1.51633 64.14
20 INF 25 1.51633 64.14
21 INF 37.367
22 54.9349 3 1.48749 70.2
23 278.88 0.3359
24 32.9209 6 1.72342 37.9
25 -90.9349 2.6 1.7185 33.5
26 25.9272 62.726
27 INF 26 1.56883 56.36
28 INF 4
29 INF 65 1.56883 56.36
30 INF 26.2672

  Here, s is a surface number, r is a radius of curvature (mm), d is a surface interval (mm), nd is a refractive index with respect to the d line, and vd is an Abbe number with respect to the d line. The surface number s1 indicates the pupil position of the objective lens 40 illustrated in FIG. Surface numbers s2 to s4 indicate optical surfaces of the imaging lens 50. Surface numbers s5 to s7 indicate optical surfaces of the prism group 60. The surface number s8 indicates the primary image surface IP1. Surface numbers s9 to s18 indicate optical surfaces of the microscope relay optical system 2. Surface numbers s19 to s21 indicate optical surfaces of the prism group 70. Surface numbers s22 to s26 indicate optical surfaces of the imaging lens 80. Surface numbers s27 to s30 indicate optical surfaces of the prism group 90. The surface interval d30 indicates the interval between the final surface (surface number s30) of the prism group 70 and the secondary image surface IP2.

The microscope relay optical system 2 according to the present example satisfies the conditional expressions (1) and (2) as represented by the following expressions (B1) and (B2). Expressions (B1) and (B2) correspond to conditional expressions (1) and (2), respectively.
f3G / F = −0.47 (B1)
f4G / F = 0.44 (B2)

  FIG. 6 is an aberration diagram of the optical system of the microscope illustrated in FIG. 5 and shows aberrations on the secondary image plane IP2 when the axial light beam enters the imaging lens 50 as parallel light parallel to the optical axis. ing. 6A is a spherical aberration diagram, FIG. 6B is an astigmatism diagram, and FIGS. 6C and 6D are an image height ratio of 0.5 and an image height ratio of 0. 0, respectively. FIG. 6E is a chromatic aberration of magnification, and FIG. 6F is a distortion aberration. It is shown that each aberration is corrected well in any state. In the figure, “M” indicates a meridional component and “S” indicates a sagittal component.

  FIG. 7 is a spot diagram of the optical system of the microscope illustrated in FIG. 5, and is a spot diagram at a position of an image height ratio of 0.8 on the secondary image plane IP2. FIG. 7A is a spot diagram in the non-eccentric state, and FIGS. 7B, 7C, 7D, and 7E are the first lens group G1 and the second lens group, respectively. It is a spot diagram in a state where G2, the third lens group G3, and the fourth lens group G4 are decentered by shifting by 0.1 mm in a direction orthogonal to the optical axis.

FIG. 8 is a cross-sectional view of an optical system of a microscope including the microscope relay optical system according to the present embodiment. The microscope relay optical system 3 illustrated in FIG. 8 is a microscope relay optical system that relays the primary image of the specimen formed by the imaging lens 50 to infinity, and the lens configuration thereof is shown in FIG. This is the same as the microscope relay optical system 1 according to Example 1 illustrated.
Hereinafter, various data according to the present embodiment will be described.

The focal length F of the microscope relay optical system 3, the focal length f3G of the third lens group G3, the focal length f4G of the fourth lens group G4, the image-side numerical aperture NAI of the microscope relay optical system 3, and the image height Each FIY is as follows.
F = 180.17 mm, f3G = −137.13 mm, f4G = 135 mm,
NAI = 0.04, FIY = 11mm

The lens data of the optical system of the microscope 300 according to this embodiment illustrated in FIG. 8 is as follows.
srd nd vd
1 INF 177.5
2 178.4248 6.1 1.48749 70.23
3 -63.4109 4 1.7185 33.52
4 -111.259 2.0047
5 INF 18 1.51633 64.14
6 INF 18 1.51633 64.14
7 INF 153.3395
8 INF 87.201
9 76.2816 5.2 1.6516 58.55
10 -80.8252 3.8 1.6727 32.1
11 -509.78 6.2577
12 33.4447 13.7 1.56883 56.36
13 22.8655 45.7834
14 INF 2.5 1.48749 70.23
15 66.85 51.2189
16 -345.554 3 1.51742 52.43
17 68.8332 3.5 1.497 81.54
18 -54.3927 1
19 INF 25 1.51633 64.14
20 INF 25 1.51633 64.14
21 INF 37.367
22 54.9349 3 1.48749 70.2
23 278.88 0.3359
24 32.9209 6 1.72342 37.9
25 -90.9349 2.6 1.7185 33.5
26 25.9272 62.726
27 INF 26 1.56883 56.36
28 INF 4
29 INF 65 1.56883 56.36
30 INF 25.9404

  Here, s is a surface number, r is a radius of curvature (mm), d is a surface interval (mm), nd is a refractive index with respect to the d line, and vd is an Abbe number with respect to the d line. The surface number s1 indicates the pupil position of the objective lens 40 illustrated in FIG. Surface numbers s2 to s4 indicate optical surfaces of the imaging lens 50. Surface numbers s5 to s7 indicate optical surfaces of the prism group 60. The surface number s8 indicates the primary image surface IP1. Surface numbers s9 to s18 indicate optical surfaces of the microscope relay optical system 3. Surface numbers s19 to s21 indicate optical surfaces of the prism group 70. Surface numbers s22 to s26 indicate optical surfaces of the imaging lens 80. Surface numbers s27 to s30 indicate optical surfaces of the prism group 90. The surface interval d30 indicates the interval between the final surface (surface number s30) of the prism group 70 and the secondary image surface IP2.

The microscope relay optical system 3 according to the present example satisfies the conditional expressions (1) and (2) as represented by the following expressions (C1) and (C2). Expressions (C1) and (C2) correspond to conditional expressions (1) and (2), respectively.
f3G / F = −0.76 (C1)
f4G / F = 0.75 (C2)

  FIG. 9 is an aberration diagram of the optical system of the microscope illustrated in FIG. 8, and shows aberrations on the secondary image plane IP2 when the axial light beam enters the imaging lens 50 as parallel light parallel to the optical axis. ing. FIG. 9A is a spherical aberration diagram, FIG. 9B is an astigmatism diagram, and FIGS. 9C and 9D are an image height ratio of 0.5 and an image height ratio of 0. 0, respectively. FIG. 9E is a coma aberration diagram at position 8, FIG. 9E is a chromatic aberration of magnification, and FIG. 9F is a distortion aberration. It is shown that each aberration is satisfactorily corrected in any state. In the figure, “M” indicates a meridional component and “S” indicates a sagittal component.

  FIG. 10 is a spot diagram of the optical system of the microscope illustrated in FIG. 8, and is a spot diagram at a position of an image height ratio of 0.8 on the secondary image plane IP2. FIG. 10A is a spot diagram in the non-eccentric state, and FIGS. 10B, 10C, 10D, and 10E show the first lens group G1 and the second lens group, respectively. It is a spot diagram in a state where G2, the third lens group G3, and the fourth lens group G4 are decentered by shifting by 0.1 mm in a direction orthogonal to the optical axis.

1, 2, 3 ... Relay optical system for microscope 10 ... Light source unit 20 ... Transmission column 30 ... Condenser 40 ... Objective lens 50, 80 ... Imaging lens 51, 82, L1 , L6... Biconvex lens 52, 81... Meniscus lens 83, L5 .. biconcave lens L2, L3... Negative meniscus lens L4 .. planoconcave lenses CL1, CL2. 90 ... Prism group 61, 62, 71, 72, 91, 92 ... Prism 100, 200, 300 ... Microscope G1 ... First lens group G2 ... Second lens group G3 ... Third lens group G4 ... Fourth lens group EP ... Light emitting surface SP ... Sample surface PP ... Pupil surface IP1 ... Primary image surface IP2 ... Secondary image surface

Claims (6)

A microscope relay optical system that relays a primary image of a specimen to infinity, in order from the primary image side,
A first lens group having a positive power and composed of a first cemented lens;
A second lens group having a negative power composed of a negative meniscus lens having a convex surface facing the primary image side;
A third lens group having a negative power, composed of a plano-concave lens having a plane facing the primary image side;
A relay optical system for a microscope, comprising: a fourth lens group having a positive power composed of a second cemented lens. The first cemented lens, in order from the primary image side,
A biconvex lens,
A negative meniscus lens having a concave surface facing the primary image side,
The second cemented lens, in order from the primary image side,
A biconcave lens,
The relay optical system for a microscope according to claim 1, comprising a biconvex lens. When F is the focal length of the microscope relay optical system and f3G is the focal length of the third lens group, the following conditional expression −0.77 <f3G / F <−0.46
3. The microscope relay optical system according to claim 2, wherein: When F is the focal length of the microscope relay optical system and f4G is the focal length of the fourth lens group, the following conditional expression 0.43 <f4G / F <0.76
The relay optical system for a microscope according to claim 2 or 3, wherein:   A microscope comprising: an objective lens; and the relay optical system for a microscope according to any one of claims 1 to 4.   The microscope according to claim 5, wherein a pupil conjugate position of the objective lens is disposed on any surface of the third lens group or the fourth lens group.