JP2009198955A - Relay optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relay optical system for making a confocal observation optical system usable in a zoom observation optical system having an objective lens. <P>SOLUTION: In a microscope device 1 having the objective lens 11, the zoom observation optical system 10 and the confocal observation optical system 30, the relay optical system 20 is arranged between an optical path division element M1 and the confocal observation optical system 30. The relay optical system 20 includes a first lens group G1 having positive refractive power, a second lens group G2 having positive refractive power, a variable aperture stop AS, and a third lens group G3 having positive refractive power, which are arranged in order from the optical path division element M1 side. A primary image of a sample 10A formed on a primary imaging surface IM1 by the first lens group G1 is formed as a secondary image of the sample 10A on a secondary imaging surface IM2 by the second lens group G2 and the third lens group G3, and also the variable aperture stop AS is arranged at a position nearly conjugate to a rear side focal position (pupil position) P1 of the objective lens 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a relay optical system, and more particularly to a relay optical system for enabling the use of a confocal observation optical system in a zoom observation optical system having an objective lens.

The applicant has an objective lens, an aperture stop, an afocal zoom system, and an imaging optical system, which are arranged in order from the specimen side, and the magnification range can be easily expanded by exchanging the objective lens. A zoom microscope that can be used has been proposed (see, for example, Patent Document 1).
JP 2006-178440 A

  Conventionally, there is a scanning confocal microscope as a microscope that irradiates a sample with light and receives light reflected by the sample to measure the surface shape of the sample. In measurement of a sample using a scanning confocal microscope, the surface of the sample is scanned with light (for example, laser light) by a scanning optical system. Light from the sample (for example, reflected light) is received by the light receiving element through the confocal observation optical system, and the height distribution information of the sample, ultra-deep image (image with very deep depth of focus), etc. Image information is acquired. When the distance between the specimen placed on the stage and the objective lens is changed in the optical axis direction, the intensity of light entering the light receiving element through the pinhole of the confocal observation optical system (the amount of received light) changes, The amount of received light is maximized when the surface of the specimen is in focus. Therefore, the height information of the surface of the sample is calculated from the distance information between the sample and the objective lens when the maximum amount of received light is obtained, and the height distribution of the surface of the sample is obtained by scanning the surface of the sample with light. Be able to.

  By the way, in recent years, in the medical / biological field, from observation of conventional cell units, observation using relatively large living body specimens (such as nematodes and zebrafish) or expression of specific genes in vivo Observation with a wide field of view has come to be performed, and there has been a demand for obtaining a tomographic image of the focal plane, which is a feature of the confocal microscope. In view of this, it has been proposed to incorporate a confocal microscope into the zoom microscope of Patent Document 1 having a variable magnification range of extremely low magnification to middle magnification (about 0.5 to 40 times).

  Here, in the zoom microscope of Patent Document 1, the entrance pupil position of the objective lens does not change during zooming of the afocal zoom system, but it is connected by an aperture stop provided between the objective lens and the afocal zoom system. The exit pupil position of the image optical system moves. Although this does not cause any significant inconvenience in normal usage in a zoom microscope, such as visual observation or image acquisition using an image sensor, in order to obtain a uniform image in a confocal microscope, In order to prevent a decrease in the amount of light at the portion, it is necessary to set a strict pupil conjugate position, which is not preferable.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a relay optical system for enabling the use of a confocal observation optical system in a zoom observation optical system having an objective lens. To do.

  In order to achieve such an object, the present invention includes an objective lens, a zoom observation optical system, and a confocal observation optical system, and the light from the specimen emitted from the objective lens is reflected by the optical path dividing element. In a microscope apparatus configured to be guided to a zoom observation optical system and the confocal observation optical system, a relay optical system is disposed between the optical path dividing element and the confocal observation optical system, and the relay optical system is The first lens group having positive refractive power, the second lens group having positive refractive power, the variable aperture stop, and the third lens group having positive refractive power, which are arranged in order from the optical path dividing element side. A primary image of the specimen imaged on a primary imaging plane by the first lens group, and a secondary image of the specimen on a secondary imaging plane by the second lens group and the third lens group. The variable aperture stop is formed as an image. The characterized in that arranged in a position substantially conjugate with the back focal position of the objective lens.

  According to the present invention, in a microscope apparatus having an objective lens and a zoom observation optical system, in order to enable the use of a confocal observation optical system, fluctuations in the pupil position of the objective lens accompanying zooming of the zoom observation optical system are reduced. It is possible to provide a relay optical system that can satisfactorily transmit the sample image formed by the objective lens to the confocal observation optical system while suppressing the image.

  Hereinafter, the present embodiment will be described with reference to the drawings. The relay optical system 20 according to the present embodiment includes a zoom observation optical system 10 having an objective lens 11 and a confocal observation optical system 30, and the light from the sample 10 </ b> A emitted from the objective lens 11 is an optical path dividing element. In the microscope apparatus 1 configured to guide the zoom observation optical system 10 and the confocal observation optical system 30 by M1, it is provided between the optical path dividing element M1 and the confocal observation optical system 30.

  First, the microscope apparatus 1 will be described. As shown in FIG. 1, the microscope apparatus 1 includes a zoom observation optical system 10, a relay optical system 20, and a confocal observation optical system 30.

  The zoom observation optical system 10 includes an objective lens 11, a (variable) aperture stop 12, an afocal zoom system 13, and an imaging optical system 14, which are arranged in order from the specimen 10A side. A light beam generated from each point of the specimen 10A is converted into a parallel light beam through the objective lens 11, is scaled through the afocal zoom system 13, is condensed through the imaging optical system 14, and the image plane I To reach. In order to observe the image of the specimen 10A formed on the image plane I, an image sensor such as a CCD is disposed on the image plane I. Further, instead of the imaging optical system 14, an observation binocular tube (eyepiece tube) including an equivalent imaging optical system, a photographic straight tube, an observation / photographing trinocular tube, and the like may be arranged depending on the application. Is possible. By using the zoom observation optical system 10 having such a configuration, it is possible to vertically observe the specimen 10A and acquire an image.

  The observation magnification is determined by the ratio between the focal length of the objective lens 11 and the focal length of the afocal zoom system 13 (combined with the imaging optical system 14). The objective lens 11 is an infinity correction type, and the rear focal plane of the objective lens 11 (so-called pupil position of the objective lens 11) is between the objective lens 11 and the afocal zoom system 13.

  An optical path splitting element M1 is provided between the objective lens 11 and the afocal zoom system 13. The optical path splitting element M1 includes a half mirror or a total reflection mirror, and the light beam generated from the specimen 10A emitted from the objective lens 11 is transmitted to the zoom observation optical system 10 (afocal zoom system 13) and the confocal observation optical system 30. Lead. In addition, the optical path splitting element M1 can be inserted and removed according to the intended use.

  Between the optical path dividing element M1 and the confocal observation optical system 30, the relay optical system 20 according to the present embodiment is provided. The relay optical system 20 includes a first lens group G1 having a positive refractive power, arranged in order from the optical path dividing element M1 side (that is, arranged in order from the sample 10A side), a bending mirror M2, and a positive refractive power. It has a second lens group G2, a variable aperture stop AS, and a third lens group G3 having a positive refractive power. The variable aperture stop AS is disposed at a position substantially conjugate with the rear focal position (pupil position) P1 of the objective lens 11. In the relay optical system 20 having this configuration, the light beam from the specimen 10A guided by the optical path splitting element M1 is condensed by the first lens group G1, and after the optical path is deflected by the bending mirror M2, the primary coupling is performed. The image is formed as a primary image of the specimen 10A on the image plane IM1, and is formed as a secondary image of the specimen 10A on the secondary imaging plane IM2 by the third lens group G3 via the second lens group G2 and the variable aperture stop AS. The

  When observing the secondary image of the specimen 10A imaged on the secondary imaging surface IM2, when observing the entire field of view, the aperture diameter of the variable aperture stop AS is reduced and a part of the field of view is enlarged. When observing, the aperture diameter of the variable aperture stop AS is increased so that the maximum numerical aperture of the objective lens 11 can be used. Further, it is preferable that the variable aperture stop AS is variable in conjunction with zooming of the afocal zoom system 13 so that the numerical apertures of the zoom observation optical system 10 and the relay optical system 20 are substantially the same. .

  The confocal observation optical system 30 includes a scanning lens GS and a scanning optical system 31. The pupil of the objective lens 11 is formed by the third lens group G3 and the scanning lens GS on the pupil conjugate plane P2 located on the opposite side of the secondary imaging plane IM2 of the scanning lens GS. The confocal observation optical system 30 can be appropriately used by arranging the scanning optical system 31 on the pupil conjugate plane P2.

  Hereinafter, features of the relay optical system 20 according to the present embodiment will be described in detail. As described above, the relay optical system 20 includes the first lens group G1 having a positive refractive power arranged in order from the optical path dividing element M1 side (that is, arranged in order from the sample 10A side), and the positive refractive power. Of the sample 10A having a second lens group G2, a variable aperture stop AS, and a third lens group G3 having a positive refractive power, and formed on the primary imaging plane IM1 by the first lens group G1. A primary image is formed as a secondary image of the specimen 10A on the secondary imaging surface IM2 by the third lens group G3 via the second lens group G2, and the variable aperture stop AS is positioned at the rear focal position of the objective lens 11 ( It is characterized by being arranged so as to be substantially conjugate with the pupil position P1.

  In the relay optical system 20 according to the present embodiment having such a configuration, the distance from the rear focal position P1 of the objective lens 11 to the secondary imaging plane IM2 is ΣD, and the focal length of the first lens group G1 is f1. It is preferable that the condition of the following formula (1) is satisfied.

    0.25 <f1 / ΣD <0.4 (1)

  The conditional expression (1) is a condition for the relay optical system 20 according to the present embodiment to obtain good imaging performance while satisfying the predetermined pupil position and image position. If the lower limit value of the conditional expression (1) is not reached, the positive refractive power of the first lens group G1 becomes strong, and it becomes difficult to correct aberrations generated in the first lens group G1, particularly spherical aberration. When observing with a light beam having a high numerical aperture, the imaging performance deteriorates, which is not preferable. Further, since the imaging magnification in the second lens group G2 and the third lens group G3 is further increased, the influence of various aberrations generated in the second lens group G2 and the third lens group G3 is increased, which is not preferable. . On the other hand, if the upper limit value of conditional expression (1) is exceeded, the distance between the first lens group G1 and the second lens group G2 becomes large, so that the incident height of the peripheral luminous flux at the second lens group G2 increases. Further, it is difficult to correct off-axis aberrations, particularly astigmatism and coma aberration, and imaging performance deteriorates when the entire screen is observed with a light beam having a low numerical aperture.

  In the relay optical system 20 of the present embodiment, the first lens group G1 is arranged in order from the optical path dividing element M1 side (that is, arranged in order from the sample 10A side), and has a weak positive or negative refractive power. The front group GF has a group GF and a rear group GR having a positive refractive power, and the front group GF has a single meniscus lens having a concave surface facing the optical path splitting element M1 or a concave surface facing the optical path splitting element M1. It is preferable that the lens is composed of a meniscus cemented lens as a whole. As a result, the front group GF causes the peripheral light beam from the pupil of the objective lens 11 to be incident on a surface that is close to a concentric circle. In addition to having a function to prevent, it also has a function to correct aberrations near the center of the screen, particularly spherical aberration and coma aberration, when observing a part of the field of view with magnification. The rear group GR bears most of the refractive power of the first lens group G1 and has a function of correcting axial chromatic aberration.

  In the relay optical system 20 of the present embodiment, the focal length of the front group GF of the first lens group G1 is f11, and the surface of the front group GF closest to the specimen 10A from the rear focal position (pupil position) P1 of the objective lens 11 is used. It is preferable to satisfy the conditions of the following expressions (2) and (3), where DP is the distance up to DP and the radius of curvature of the surface of the front group GF closest to the specimen 10A is r1.

f1 / | f11 | <0.7 (2)
−1.2 <r1 / DP <−0.4 (3)

  The conditional expressions (2) and (3) are conditions indicating the optimum lens configuration of the first lens group G1.

  The conditional expression (2) is a condition that defines an appropriate refractive power of the front group GF constituting the first lens group G1. If this conditional expression (2) cannot be satisfied, the refractive power of the front group GF becomes strong, and the ability to correct spherical aberration and coma aberration deteriorates when magnifying a part of the field of view. Absent.

  The conditional expression (3) defines an appropriate shape of the front group GF. More specifically, the conditional expression (3) is closest to the rear focal position (pupil position) P1 of the objective lens 11 and is closest to the front group GF. This is a condition for arranging the center of curvature of the surface on the specimen 10A side. When the lower limit value of the conditional expression (3) is not reached, the radius of curvature of the surface of the front group GF closest to the specimen 10A becomes large, and when observing the entire field of view, aberrations in the peripheral area of the screen, especially field curvature aberrations are observed. Since it will deteriorate, it is not preferable. On the other hand, when the value exceeds the upper limit value of conditional expression (3), correction of spherical aberration and coma aberration becomes excessive when magnifying a part of the field of view, which is not preferable.

In the relay optical system 20 of the present embodiment, the first lens group G1 has nd ₁ <1.6 and νd ₁ > 65 when the refractive index for the d-line is nd ₁ and the Abbe number is νd ₁ . When there is at least one convex lens using a glass material that satisfies the conditions, the focal length of the first lens group G1 is f1, and the focal length of the convex lens of the first lens group G1 is f1P, the following equation (4) It is preferable to satisfy the following conditions.

    0.25 <f1P / f1 <0.5 (4)

  The above conditions are conditions for the first lens group G1 to achieve good chromatic aberration correction. In the present embodiment, the first lens group G1 has a function of forming a light beam emitted from the surface of the specimen 10A and made substantially parallel to the objective lens 11 on the primary imaging plane IM1, and a rear focal position P1 of the objective lens 11. As well as the second lens group G2 in the vicinity of the variable aperture stop AS. Therefore, good correction of various aberrations (particularly longitudinal chromatic aberration and lateral chromatic aberration) of the first lens group G1 leads to good imaging performance on the secondary imaging surface IM2.

  In the present embodiment, the first lens group G1 satisfies the condition that it has at least one convex lens G1P using a glass material that satisfies the conditions of nd <1.6 and νd> 65, and the conditional expression (4). This makes it possible to correct chromatic aberration. The former condition is to secure the correction ability of the chromatic aberration of the convex lens G1P included in the first lens group G1, and the conditional expression (4) defines the optimum refractive power of the convex lens G1P. . Note that if the lower limit value of conditional expression (4) is not reached, the refractive power of the convex lens G1P becomes strong, and correction of chromatic aberration becomes excessive, which is not preferable. On the other hand, when the value exceeds the upper limit value of the conditional expression (4), the refractive power of the convex lens G1P becomes weak, so that correction of chromatic aberration becomes insufficient, which is also not preferable.

In the relay optical system 20 of the present embodiment, the third lens group G3 has nd ₃ <1.6 and νd ₃ > 65 when the refractive index for the d-line is nd ₃ and the Abbe number is νd ₃ . When there is at least one convex lens using a glass material that satisfies the conditions, the focal length of the third lens group is f3, and the focal length of the convex lens of the third lens group is f3P, the condition of the following equation (5) Is preferably satisfied.

    0.4 <f3P / f3 <1.5 (5)

  The above conditions are conditions for the third lens group G3 to achieve good chromatic aberration correction. The third lens group G3 has a function of forming an image of light from the specimen 10A (which has passed through the first lens group G1, the second lens group G2, and the variable aperture stop AS) on the secondary imaging surface IM2. . For this reason, it is a condition for maintaining good imaging performance on the secondary imaging surface IM2 to satisfactorily correct the axial chromatic aberration and lateral chromatic aberration of the third lens group G3. Here, the third lens group G3 satisfies the condition of having at least one convex lens G3P using a glass material that satisfies the conditions of nd <1.6 and νd> 65, and the conditional expression (5). This makes it possible to correct chromatic aberration. The former condition is to secure the correction ability of the chromatic aberration of the convex lens G3P of the third lens group G3, and the conditional expression (5) defines the optimum refractive power of the convex lens G3P. . Note that if the lower limit value of conditional expression (5) is not reached, the refractive power of the convex lens G3P becomes strong, and correction of chromatic aberration is excessive, which is not preferable. On the other hand, when the value exceeds the upper limit value of the conditional expression (5), the refractive power of the convex lens G3P of the third lens group becomes weak.

  Hereinafter, each example according to the present embodiment will be described with reference to the drawings. Tables 1 to 5 are shown below, but these are tables of specifications in the first to fifth examples. In [Surface data], f is the combined focal length of the relay optical system 20 according to each embodiment, the surface number is the order of the lens surfaces from the object side along the traveling direction of the light beam, and r is each lens surface. , D is the surface spacing, which is the distance on the optical axis from each optical surface to the next optical surface (or image surface), nd is the refractive index for the d-line (wavelength 587.6 nm), and νd is Abbe Indicates a number. Note that OP represents a surface with an objective cylinder, P1 represents a pupil plane of the objective lens 11, M1 represents an optical path dividing element (mirror), M2 represents a bending mirror, and AS represents a variable aperture stop. The curvature radius “0.0000” indicates a plane or an opening. In [various data], M indicates the magnification of the zoom observation optical system, Y indicates the image height on the secondary image plane IM2, and fai indicates the aperture diameter of the variable aperture stop AS. In [Conditional Expression], values corresponding to the conditional expressions (1) to (5) are shown.

  In the table, “mm” is generally used as the unit of focal length f, radius of curvature r, surface interval d, and other lengths. However, since the optical system can obtain the same optical performance even when proportionally enlarged or proportionally reduced, the unit is not limited to “mm”, and other appropriate units can be used.

  The description of the above table is the same in other examples, and the description thereof is omitted.

(First embodiment)
The relay optical system 20 according to the first example will be described with reference to FIGS. 2, 3, 4 and Table 1. FIG. FIG. 2 is a cross-sectional view illustrating a lens configuration of the relay optical system 20 according to the first example. As shown in FIG. 2, the relay optical system 20 according to the first example is arranged in order from the specimen 10 </ b> A side (objective surface OP, objective lens pupil plane P <b> 1, optical path splitting element M <b> 1). A first lens group G1 having a refractive power of 1, a bending mirror M2, a second lens group G2 having a positive refractive power, a variable aperture stop AS, and a third lens group G3 having a positive refractive power. Configured.

  The first lens group G1 is formed by joining a front group GF composed of a negative meniscus lens L11 having a convex surface toward the image side and a negative meniscus lens L12 having a concave surface toward the image side and a biconvex lens L13 arranged in order from the sample side. The rear group GR is composed of a lens. The second lens group G2 includes a positive meniscus lens L21 having a convex surface directed to the image side, a cemented lens of a negative meniscus lens L22 having a concave surface directed to the image side, and a biconvex lens L23, and the image side. And a positive meniscus lens L24 having a concave surface facing the lens, and a biconcave lens L25. The third lens group G3 includes a cemented lens of a biconcave lens L31 and a biconvex lens L32, a cemented lens of a biconvex lens L33 and a biconcave lens L34, and a biconvex lens L35, which are arranged in order from the sample side.

  The relay optical system 20 according to the present embodiment having such a configuration uses the second lens group G2 and the third lens group G3 to generate a primary image of the specimen imaged on the primary imaging surface IM1 by the first lens group G1. It is configured to form an image as a secondary image of the sample on the secondary imaging surface IM2. In FIG. 1, the primary imaging plane IM1 is omitted.

  The variable aperture stop AS is located between the second lens group G2 and the third lens group G3, and is disposed at a position substantially conjugate with the rear focal position (pupil position) P1 of the objective lens 11. The variable aperture stop AS has a variable aperture diameter so that the NA is substantially equal to the NA of the zoom observation optical system 10 described above.

  Table 1 shows a table of specifications in the first embodiment. In addition, the surface numbers 1-27 in Table 1 respond | correspond to the surfaces 1-27 shown in FIG.

The first lens group G1 is a convex lens using a glass material that satisfies the conditions of nd ₁ <1.6 and νd ₁ > 65, where the refractive index for the d-line is nd ₁ and the Abbe number is νd _1. And a biconvex lens L13 (corresponding to surface numbers 7 and 8). The third lens group G3 is a convex lens using a glass material that satisfies the conditions of nd ₃ <1.6 and νd ₃ > 65, where the refractive index for the d-line is nd ₃ and the Abbe number is νd _3. , And biconvex lenses L32 and L33 (surface numbers 20, 21 and surface numbers 23, 24).

(Table 1)
[Surface data]
f = 100
Surface number r d nd νd
1 0.0000 10.0000 1.000000 Surface with objective cylinder OP
2 0.0000 20.0000 1.000000 Objective lens pupil plane P1
3 0.0000 22.0000 1.000000 Optical path splitter M1
4 -39.0489 2.0000 1.516800 64.10
5 -53.8869 0.5000 1.000000
6 65.7092 2.0000 1.696800 55.60
7 29.9500 6.0000 1.497820 82.52
8 -56.4114 20.0000 1.000000
9 0.0000 116.0000 1.000000 Bending mirror M2
10 -96.3987 4.5000 1.603110 60.64
11 -24.8859 0.5000 1.000000
12 43.3698 2.0000 1.713000 53.93
13 13.9986 8.0000 1.497820 82.52
14 -36.5677 0.5000 1.000000
15 10.9376 4.5000 1.603110 60.64
16 17.9274 8.0000 1.000000
17 -33.9433 1.5000 1.688930 31.08
18 5.1757 2.0000 1.000000
19 0.0000 5.5000 1.000000 Variable aperture stop AS
20 -58.5331 1.5000 1.516800 64.10
21 13.1764 6.0000 1.497820 82.52
22 -8.6870 0.5000 1.000000
23 146.2677 6.0000 1.497820 82.52
24 -9.0832 1.5000 1.696800 55.60
25 249.2480 0.5000 1.000000
26 38.0553 4.0000 1.603110 60.64
27 -28.3532 42.8011 1.000000
[Various data]
M 1.0000 8.0000
Y 9.0000 1.1250
Fai 1.3800 4.4800
[Conditional expression]
f1 = 105.1171
ΣD = 288.3011
f11 = -287.6157
r1 = -39.0489
DP = 42.0000
f1P = 40.2270
f3 = 16.8549
f3P = 11.5721,17.4026
Conditional expression (1) f1 / ΣD = 0.3646
Conditional expression (2) f1 / | f11 | = 0.3655
Conditional expression (3) r1 / DP = -0.9297
Conditional expression (4) f1P / f1 = 0.3827
Conditional expression (5) f3P / f3 = 0.6866,1.0325

  From the table of specifications shown in Table 1, it can be seen that the relay optical system 20 according to the first example satisfies all the conditional expressions (1) to (5).

  FIG. 3 shows various aberration diagrams when the magnification of the zoom observation optical system is 1 in the relay optical system 20 according to the first example. FIG. 4 shows various aberration diagrams when the magnification of the zoom observation optical system is 8 × in the relay optical system 20 according to the first example.

  In the spherical aberration diagram, FNO represents the F number corresponding to the maximum aperture. In the astigmatism diagram and the distortion diagram, Y represents the maximum image height. In the coma aberration diagram, Y indicates the value of each image height. In the astigmatism diagram, the solid line indicates the sagittal image plane, and the broken line indicates the meridional image plane. Further, in the distortion diagram, the aberration with respect to the d-line as the reference wavelength is shown. Further, d indicates various aberrations with respect to the d-line (wavelength 587.6 nm), g indicates various aberrations with respect to the g-line (wavelength 435.8 nm), and those not described indicate various aberrations with respect to the d-line. The explanation of the above aberration diagrams is the same in the other examples, and the explanation is omitted.

  As is apparent from the respective aberration diagrams shown in FIGS. 3 and 4, it can be seen that in the relay optical system 20 according to the first example, various aberrations are well corrected and excellent imaging performance is ensured. .

(Second embodiment)
The relay optical system 20 according to the second example will be described with reference to FIGS. FIG. 5 is a sectional view showing the lens configuration of the relay optical system 20 according to the second example. As shown in FIG. 5, the relay optical system 20 according to the second example is arranged in order from the sample side (positive surface with objective cylinder OP, objective lens pupil plane P1, and optical path dividing element M1). A first lens group G1 having a refractive power; a bending mirror M2; a second lens group G2 having a positive refractive power; a variable aperture stop AS; and a third lens group G3 having a positive refractive power. Configured.

  The first lens group G1 is formed by joining a front group GF composed of a negative meniscus lens L11 having a convex surface toward the image side and a negative meniscus lens L12 having a concave surface toward the image side and a biconvex lens L13 arranged in order from the sample side. The rear group GR is composed of lenses. The second lens group G2 includes a cemented lens of a negative meniscus lens L21 having a concave surface facing the image side and a biconvex lens L22, a positive meniscus lens L23 having a concave surface facing the image side, and a biconcave lens. L24. The third lens group G3 includes a negative meniscus lens L31 having a concave surface facing the image side and a biconvex lens L32 arranged in order from the sample side, and a negative meniscus lens L34 having a biconvex lens L33 and a convex surface facing the image side. And a biconvex lens L35.

  The relay optical system 20 according to the present embodiment having such a configuration uses the second lens group G2 and the third lens group G3 to generate a primary image of the specimen imaged on the primary imaging surface IM1 by the first lens group G1. It is configured to form an image as a secondary image of the sample on the secondary imaging surface IM2. In FIG. 5, the primary imaging plane IM1 is omitted.

  The variable aperture stop AS is located between the second lens group G2 and the third lens group G3, and is disposed at a position substantially conjugate with the rear focal position (pupil position) P1 of the objective lens 11. The variable aperture stop AS has a variable aperture diameter so that the NA is substantially equal to the NA of the zoom observation optical system 10 described above.

  Table 2 shows a table of specifications in the second embodiment. Note that surface numbers 1 to 25 in Table 2 correspond to surfaces 1 to 25 shown in FIG.

The first lens group G1 is a convex lens using a glass material that satisfies the conditions of nd ₁ <1.6 and νd ₁ > 65, where the refractive index for the d-line is nd ₁ and the Abbe number is νd _1. And a biconvex lens L13 (corresponding to surface numbers 7 and 8). The third lens group G3 is a convex lens using a glass material that satisfies the conditions of nd ₃ <1.6 and νd ₃ > 65, where the refractive index for the d-line is nd ₃ and the Abbe number is νd _3. , And biconvex lenses L32 and L33 (surface numbers 19 and 20 and surface numbers 21 and 22).

(Table 2)
[Surface data]
f = 100
Surface number r d nd νd
1 0.0000 10.0000 1.000000 Surface with objective cylinder OP
2 0.0000 20.0000 1.000000 Objective lens pupil plane P1
3 0.0000 22.0000 1.000000 Optical path splitter M1
4 -32.3500 2.0000 1.772789 49.45
5 -38.5266 0.5000 1.000000
6 74.2146 2.0000 1.772789 49.45
7 36.8537 6.0000 1.497820 82.52
8 -52.4711 20.0000 1.000000
9 0.0000 111.0000 1.000000 Bending mirror M2
10 199.9465 2.0000 1.804540 39.61
11 22.9204 9.0000 1.620409 60.14
12 -25.2396 0.5000 1.000000
13 15.3842 6.0000 1.620409 60.14
14 91.2852 11.5000 1.000000
15 -10.6556 1.5000 1.672700 32.17
16 7.3459 1.0000 1.000000
17 0.0000 7.5000 1.000000 Variable aperture stop AS
18 43.3704 1.5000 1.696800 55.60
19 19.4161 6.5000 1.497820 82.52
20 -10.6155 0.5000 1.000000
21 6037.7963 6.0000 1.497820 82.52
22 -10.2993 1.5000 1.696800 55.60
23 -40.2639 0.5000 1.000000
24 55.2268 3.0000 1.589130 61.09
25 -78.8452 46.0756 1.000000
[Various data]
M 1.0000 8.0000
Y 9.0000 1.1250
Fai 1.3000 4.2000
[Conditional expression]
f1 = 105.3067
ΣD = 288.0756
f11 = -304.0255
r1 = -32.3500
DP = 42.0000
f1P = 44.4798
f3 = 16.5477
f3P = 14.8550,20.6605
Conditional expression (1) f1 / ΣD = 0.3656
Conditional expression (2) f1 / | f11 | = 0.3464
Conditional expression (3) r1 / DP = -0.7702
Conditional expression (4) f1P / f1 = 0.4224
Conditional expression (5) f3P / f3 = 0.8977,1.2485

  From the specification table shown in Table 2, it can be seen that the relay optical system 20 according to the second example satisfies all the conditional expressions (1) to (5).

  FIG. 6 shows various aberration diagrams when the magnification of the zoom observation optical system is 1 in the relay optical system 20 according to the second example. FIG. 7 shows various aberration diagrams when the magnification of the zoom observation optical system is 8 × in the relay optical system 20 according to the second example. As is apparent from the respective aberration diagrams shown in FIGS. 6 and 7, it can be seen that in the relay optical system 20 according to the second example, various aberrations are corrected well and excellent imaging performance is ensured. .

(Third embodiment)
The relay optical system 20 according to the third example will be described with reference to FIGS. 8, 9, 10 and Table 3. FIG. FIG. 8 is a sectional view showing the lens configuration of the relay optical system 20 according to the third example. As shown in FIG. 8, the relay optical system 20 according to the third example is arranged in order from the sample side (a surface with an objective cylinder OP, an objective lens pupil plane P1, and an optical path splitting element M1). A first lens group G1 having a refractive power; a bending mirror M2; a second lens group G2 having a positive refractive power; a variable aperture stop AS; and a third lens group G3 having a positive refractive power. Configured.

  The first lens group G1 is composed of a front lens group GF composed of a positive meniscus lens having a convex surface facing the image side and a cemented lens of a negative meniscus lens having a concave surface facing the image side and a biconvex lens arranged in order from the sample side. It consists of rear group GR. The second lens group G2 includes a biconvex lens L21 arranged in order from the sample side, a cemented lens of a negative meniscus lens L22 having a concave surface on the image side and a positive meniscus lens L23 having a concave surface on the image side, and an image side. And a negative meniscus lens L24 having a concave surface facing the surface. The third lens group G3 includes a cemented lens of a biconcave lens L31 and a biconvex lens L32, a cemented lens of a biconvex lens L33 and a negative meniscus lens L34 having a convex surface facing the image side, and a biconvex lens arranged in order from the sample side. L35.

  The relay optical system 20 according to the present embodiment having such a configuration uses the second lens group G2 and the third lens group G3 to generate a primary image of the specimen imaged on the primary imaging surface IM1 by the first lens group G1. It is configured to form an image as a secondary image of the sample on the secondary imaging surface IM2. In FIG. 8, the primary imaging plane IM1 is omitted.

  The variable aperture stop AS is located between the second lens group G2 and the third lens group G3, and is disposed at a position substantially conjugate with the rear focal position (pupil position) P1 of the objective lens 11. The variable aperture stop AS has a variable aperture diameter so that the NA is substantially equal to the NA of the zoom observation optical system 10 described above.

  Table 3 shows a table of specifications in the third embodiment. The surface numbers 1 to 25 in Table 3 correspond to the surfaces 1 to 25 shown in FIG.

The first lens group G1 is a convex lens using a glass material that satisfies the conditions of nd ₁ <1.6 and νd ₁ > 65, where the refractive index for the d-line is nd ₁ and the Abbe number is νd _1. And a biconvex lens L13 (corresponding to surface numbers 7 and 8). The third lens group G3 is a convex lens using a glass material that satisfies the conditions of nd ₃ <1.6 and νd ₃ > 65, where the refractive index for the d-line is nd ₃ and the Abbe number is νd _3. , And biconvex lenses L32 and L33 (surface numbers 19 and 20 and surface numbers 21 and 22).

(Table 3)
[Surface data]
f = 100
Surface number r d nd νd
1 0.0000 10.0000 1.000000 Surface with objective cylinder OP
2 0.0000 20.0000 1.000000 Objective lens pupil plane P1
3 0.0000 21.0000 1.000000 Optical path splitter M1
4 -20.2304 2.5000 1.603110 60.64
5 -19.8760 0.5000 1.000000
6 108.9076 2.0000 1.696800 55.60
7 23.8144 6.5000 1.497820 82.52
8 -48.7242 20.0000 1.000000
9 0.0000 116.0000 1.000000 Bending mirror M2
10 48.4606 5.0000 1.772789 49.45
11 -57.8797 0.5000 1.000000
12 14.6823 2.0000 1.803840 33.89
13 9.2641 7.0000 1.497820 82.52
14 44.1853 9.5000 1.000000
15 9.0517 2.0000 1.795040 28.56
16 4.8144 4.0000 1.000000
17 0.0000 4.5000 1.000000 Variable aperture stop AS
18 -7.2597 1.5000 1.696800 55.60
19 14.7837 5.0000 1.497820 82.52
20 -8.8545 0.5000 1.000000
21 25.5080 7.0000 1.497820 82.52
22 -8.3365 1.5000 1.516800 64.10
23 -25.8610 0.5000 1.000000
24 598.5743 3.0000 1.603110 60.64
25 -49.7391 48.1261 1.000000
[Various data]
M 1.0000 8.0000
Y 9.0000 1.1250
Fa 1.5500 5.2200
[Conditional expression]
f1 = 94.6988
ΣD = 290.1261
f11 = 514.8870
r1 = -20.2304
DP = 41.0000
f1P = 33.1187
f3 = 22.4936
f3P = 13.5528,11.9652
Conditional expression (1) f1 / ΣD = 0.3264
Conditional expression (2) f1 / | f11 | = 0.1839
Conditional expression (3) r1 / DP = −0.4934
Conditional expression (4) f1P / f1 = 0.3497
Conditional expression (5) f3P / f3 = 0.6025,0.5319

  From the table of specifications shown in Table 3, it can be seen that the relay optical system 20 according to the third example satisfies all the conditional expressions (1) to (5).

  FIG. 9 shows various aberration diagrams when the magnification of the zoom observation optical system is 1 in the relay optical system 20 according to the third example. FIG. 10 shows various aberration diagrams when the magnification of the zoom observation optical system is 8 × in the relay optical system 20 according to the third example. As is clear from the aberration diagrams shown in FIGS. 9 and 10, it can be seen that in the relay optical system 20 according to the third example, various aberrations are well corrected and excellent imaging performance is secured. .

(Fourth embodiment)
The relay optical system 20 according to the fourth example will be described with reference to FIGS. 11, 12, 13 and Table 4. FIG. FIG. 11 is a cross-sectional view illustrating a lens configuration of the relay optical system 20 according to the fourth example. As shown in FIG. 11, the relay optical system 20 according to the fourth example is arranged in order from the specimen side (positive surface with objective cylinder OP, objective lens pupil plane P1, and optical path dividing element M1). A first lens group G1 having a refractive power; a bending mirror M2; a second lens group G2 having a positive refractive power; a variable aperture stop AS; and a third lens group G3 having a positive refractive power. Configured.

  The first lens group G1 is formed by joining a front group GF including a positive meniscus lens L11 having a convex surface toward the image side and a negative meniscus lens L12 having a concave surface toward the image side and a biconvex lens L13, which are arranged in order from the sample side. The rear group GR is composed of lenses. The second lens group G2 includes a biconvex lens L21, a positive meniscus lens L22 having a concave surface facing the image surface, a negative meniscus lens L23 having a concave surface facing the image side, and a concave surface facing the image surface. And a cemented lens with a positive meniscus lens L24. The third lens group G3 includes a cemented lens of a biconcave lens L31 and a biconvex lens L32, a cemented lens of a biconvex lens L33 and a negative meniscus lens L34 having a convex surface facing the image side, and a biconvex lens arranged in order from the sample side. L35.

  The relay optical system 20 according to the present embodiment having such a configuration uses the second lens group G2 and the third lens group G3 to generate a primary image of the specimen imaged on the primary imaging surface IM1 by the first lens group G1. An image is formed as a secondary image of the sample on the secondary imaging surface IM2. In FIG. 11, the primary imaging plane IM1 is omitted.

  The variable aperture stop AS is located between the second lens group G2 and the third lens group G3, and is disposed at a position substantially conjugate with the rear focal position (pupil position) P1 of the objective lens 11. The variable aperture stop AS has a variable aperture diameter so that the NA is substantially equal to the NA of the zoom observation optical system 10 described above.

  Table 4 shows a table of specifications in the fourth embodiment. In addition, the surface numbers 1-25 in Table 4 respond | correspond to the surfaces 1-25 shown in FIG.

The first lens group G1 is a convex lens using a glass material that satisfies the conditions of nd ₁ <1.6 and νd ₁ > 65, where the refractive index for the d-line is nd ₁ and the Abbe number is νd _1. And a biconvex lens L13 (corresponding to surface numbers 7 and 8). The third lens group is a convex lens using a glass material that satisfies the conditions of nd ₃ <1.6 and νd ₃ > 65 when the refractive index for d-line is nd ₃ and the Abbe number is νd ₃ . Biconvex lenses L32 and L33 (surface numbers 19 and 20 and surface numbers 21 and 22) are provided.

(Table 4)
[Surface data]
f = 100
Surface number r d nd νd
1 0.0000 10.0000 1.000000 Surface with objective cylinder OP
2 0.0000 20.0000 1.000000 Objective lens pupil plane P1
3 0.0000 20.0000 1.000000 Optical path splitter M1
4 -36.4068 3.0000 1.603110 60.64
5 -27.8309 0.5000 1.000000
6 79.3604 2.0000 1.696800 55.60
7 19.8162 6.5000 1.497820 82.52
8 -88.7678 20.0000 1.000000
9 0.0000 101.0000 1.000000 Bending mirror M2
10 414.9002 3.0000 1.603110 60.64
11 -119.0380 0.5000 1.000000
12 35.0921 4.0000 1.603110 60.64
13 149.1508 0.5000 1.000000
14 17.1128 2.0000 1.696800 55.60
15 11.0615 8.0000 1.497820 82.52
16 124.9941 19.0000 1.000000
17 0.0000 3.0000 1.000000 Variable aperture stop AS
18 -4.2897 2.0000 1.654115 39.68
19 25.2398 7.0000 1.497820 82.52
20 -9.4297 1.0000 1.000000
21 88.2580 7.5000 1.497820 82.52
22 -10.5071 1.5000 1.516800 64.10
23 -18.6000 1.0000 1.000000
24 186.1969 3.0000 1.603110 60.64
25 -70.9628 56.3995 1.000000
[Various data]
M 1.0000 8.0000
Y 9.0000 1.1250
Fa 1.5400 4.9800
[Conditional expression]
f1 = 97.9460
ΣD = 292.3995
f11 = 173.1174
r1 = -36.4068
DP = 40.0000
f1P = 33.2020
f3 = 25.8344
f3P = 19.3491,14.7820
Conditional expression (1) f1 / ΣD = 0.3350
Conditional expression (2) f1 / | f11 | = 0.5658
Conditional expression (3) r1 / DP = -0.9102
Conditional expression (4) f1P / f1 = 0.3390
Conditional expression (5) f3P / f3 = 0.7490,0.5722

  It can be seen from the table of specifications shown in Table 4 that the relay optical system 20 according to the fourth example satisfies all the conditional expressions (1) to (5).

  FIG. 12 shows various aberration diagrams when the magnification of the zoom observation optical system is 1 in the relay optical system 20 according to the fourth example. FIG. 13 shows various aberration diagrams when the magnification of the zoom observation optical system is 8 × in the relay optical system 20 according to the fourth example. As is apparent from the respective aberration diagrams shown in FIGS. 12 and 13, it is understood that the relay optical system 20 according to the fourth example corrects various aberrations satisfactorily and ensures excellent imaging performance. .

(5th Example)
A relay optical system 20 according to the fifth example will be described with reference to FIGS. 14, 15, 16 and Table 5. FIG. FIG. 14 is a sectional view showing the lens configuration of the relay optical system 20 according to the fifth example. As shown in FIG. 14, the relay optical system 20 according to the fifth example is arranged in order from the sample side (positive surface with objective cylinder OP, objective lens pupil plane P1, optical path splitting element M1) and positive. A first lens group G1 having a refractive power; a bending mirror M2; a second lens group G2 having a positive refractive power; a variable aperture stop AS; and a third lens group G3 having a positive refractive power. Configured.

  The first lens group G1 includes a front group GF that is arranged in order from the sample side and includes a cemented lens of a negative meniscus lens L11 having a convex surface facing the image side and a positive meniscus lens L12 having a convex surface facing the image side. And a rear group GR composed of a cemented lens of a negative meniscus lens L13 having a concave surface facing the lens and a biconvex lens L14. The second lens group G2 includes a biconvex lens L21 arranged in order from the sample side, a cemented lens of a negative meniscus lens L22 having a concave surface on the image side and a positive meniscus lens L23 having a concave surface on the image surface, and an image side. And a negative meniscus lens L24 having a concave surface facing the surface. The third lens group G3 includes a cemented lens composed of a biconcave lens L31 and a biconvex lens L32, a cemented lens composed of a biconvex lens L33 and a negative meniscus lens L34 having a convex surface facing the image side, and an image plane, which are arranged in order from the sample side. And a positive meniscus lens L35 having a convex surface.

  The relay optical system 20 according to the present embodiment having such a configuration uses the second lens group G2 and the third lens group G3 to generate a primary image of the specimen imaged on the primary imaging surface IM1 by the first lens group G1. It is configured to form an image as a secondary image of the sample on the secondary imaging surface IM2. In FIG. 14, the primary imaging plane IM1 is omitted.

  The variable aperture stop AS is located between the second lens group G2 and the third lens group G3, and is disposed at a position substantially conjugate with the rear focal position (pupil position) P1 of the objective lens 11. The variable aperture stop AS has a variable aperture diameter so that the NA is substantially equal to the NA of the zoom observation optical system 10 described above.

  Table 5 shows a table of specifications in the fifth embodiment. In addition, the surface numbers 1-26 in Table 5 respond | correspond to the surfaces 1-26 shown in FIG.

The first lens group G1 is a convex lens using a glass material that satisfies the conditions of nd ₁ <1.6 and νd ₁ > 65, where the refractive index for the d-line is nd ₁ and the Abbe number is νd _1. And a biconvex lens L14 (corresponding to surface numbers 8 and 9). The third lens group is a convex lens using a glass material that satisfies the conditions of nd ₃ <1.6 and νd ₃ > 65 when the refractive index for d-line is nd ₃ and the Abbe number is νd ₃ . Biconvex lenses L32 and L33 (surface numbers 20, 21 and surface numbers 22, 23) are included.

(Table 5)
[Surface data]
f = 100
Surface number r d nd νd
1 0.0000 10.0000 1.000000 Surface with objective cylinder OP
2 0.0000 20.0000 1.000000 Objective lens pupil plane P1
3 0.0000 19.0000 1.000000 Optical path splitter M1
4 -24.2006 1.5000 1.613397 44.27
5 -162.7555 4.5000 1.622801 57.03
6 -24.1968 0.5000 1.000000
7 77.0175 2.0000 1.651599 58.50
8 23.0015 6.0000 1.497820 82.52
9 -102.0144 19.0000 1.000000
10 0.0000 117.0000 1.000000 Bending mirror M2
11 27.0523 5.5000 1.804109 46.54
12 -234.9228 0.5000 1.000000
13 14.3489 2.0000 1.803840 33.89
14 8.4727 7.0000 1.497820 82.52
15 25.4793 8.5000 1.000000
16 6.7106 2.0000 1.772789 49.45
17 4.2414 4.0000 1.000000
18 0.0000 4.0000 1.000000
19 -7.0758 1.5000 1.696800 55.60
20 19.5826 5.0000 1.497820 82.52
21 -8.9714 0.5000 1.000000
22 41.9846 6.0000 1.497820 82.52
23 -8.6335 1.5000 1.516800 64.10
24 -21.7393 0.5000 1.000000
25 -1742.3133 3.5000 1.603110 60.64
26 -32.7677 48.1115 1.000000
[Various data]
M 1.0000 8.0000
Y 9.0000 1.1250
Fa 1.4300 4.8000
[Conditional expression]
f1 = 100.4309
ΣD = 289.6115
f11 = 363.1974
r1 = -24.2006
DP = 39.0000
f1P = 38.3145
f3 = 20.8178
f3P = 14.9745, 13.1230
Conditional expression (1) f1 / ΣD = 0.3468
Conditional expression (2) f1 / | f11 | = 0.2765
Conditional expression (3) r1 / DP = −0.6205
Conditional expression (4) f1P / f1 = 0.3815
Conditional expression (5) f3P / f3 = 0.7193,0.6304

  From the table of specifications shown in Table 5, it can be seen that the relay optical system 20 according to the fifth example satisfies all the conditional expressions (1) to (5).

  FIG. 15 shows various aberration diagrams when the magnification of the zoom observation optical system is 1 in the relay optical system 20 according to the fifth example. FIG. 16 shows various aberration diagrams when the magnification of the zoom observation optical system is 8 × in the relay optical system 20 according to the fifth example. As is apparent from the respective aberration diagrams shown in FIGS. 15 and 16, it can be seen that in the relay optical system 20 according to the fifth example, various aberrations are well corrected and excellent imaging performance is secured. .

  According to the present invention having the above-described configuration, in the zoom observation optical system 10 having the objective lens 11, the zoom observation optical system 10 is accompanied by zooming so that the confocal observation optical system 30 can be used. The relay optical system 20 that can satisfactorily transmit the sample 10A image formed by the objective lens 11 to the confocal observation optical system 30 while suppressing the fluctuation of the pupil position of the objective lens 11 can be provided.

  The present invention as described above is not limited to the above-described embodiment, and can be appropriately improved as long as it does not depart from the gist of the present invention.

It is a schematic block diagram which shows the zoom microscope and relay optical system to which this invention is applied. It is a lens block diagram of the microscope objective lens which concerns on 1st Example. FIG. 7 is an aberration diagram when the magnification of the zoom observation optical system is 1 in the relay optical system according to the first example. FIG. 12 is a diagram illustrating various aberrations when the magnification of the zoom observation optical system is 8 × in the relay optical system according to the first example. It is a lens block diagram of the microscope objective lens which concerns on 2nd Example. FIG. 11 is a diagram illustrating all aberrations when the magnification of the zoom observation optical system is 1 in the relay optical system according to the second example. FIG. 11 is a diagram illustrating all aberrations when the magnification of the zoom observation optical system is 8 × in the relay optical system according to the second example. It is a lens block diagram of the microscope objective lens which concerns on 3rd Example. FIG. 11 is a diagram illustrating all aberrations when the magnification of the zoom observation optical system is 1 in the relay optical system according to the third example. FIG. 12 is a diagram illustrating various aberrations when the magnification of the zoom observation optical system is 8 × in the relay optical system according to the third example. It is a lens block diagram of the microscope objective lens which concerns on 4th Example. FIG. 10 is various aberration diagrams when the magnification of the zoom observation optical system is 1 in the relay optical system according to the fourth example. FIG. 44 is various aberration diagrams when the magnification of the zoom observation optical system is 8 × in the relay optical system according to the forty-first example. It is a lens block diagram of the microscope objective lens which concerns on 5th Example. FIG. 11 is a diagram illustrating all aberrations when the magnification of the zoom observation optical system is 1 in the relay optical system according to the fifth example. FIG. 12 is a diagram illustrating all aberrations when the magnification of the zoom observation optical system is 8 × in the relay optical system according to the fifth example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microscope apparatus 10 Zoom observation optical system 10A Sample 11 Objective lens 12 1st variable aperture stop 13 Afocal zoom system 14 Imaging optical system I Image surface M1 Optical path dividing element 20 Relay optical system G1 1st lens group G2 2nd lens group G3 Third lens group AS Variable aperture stop M2 Bending mirror 30 Confocal observation optical system 31 Scanning optical system GS Scanning lens P1 Objective lens pupil position P2 Objective lens pupil conjugate plane IM1 Primary imaging plane IM2 Secondary imaging plane

Claims (6)

An objective lens, a zoom observation optical system, and a confocal observation optical system, and the light emitted from the specimen emitted from the objective lens is transmitted to the zoom observation optical system and the confocal observation optical system by an optical path dividing element. In the microscope apparatus configured to guide, a relay optical system is disposed between the optical path splitting element and the confocal observation optical system,
The relay optical system is
A first lens group having a positive refractive power, a second lens group having a positive refractive power, a variable aperture stop, and a third lens group having a positive refractive power, which are arranged in order from the optical path dividing element side. Have
The primary image of the specimen imaged on the primary imaging plane by the first lens group is imaged as a secondary image of the specimen on the secondary imaging plane by the second lens group and the third lens group. With
A relay optical system, wherein the variable aperture stop is disposed at a position substantially conjugate with a rear focal position of the objective lens. When the distance from the back focal position of the objective lens to the secondary imaging plane is ΣD, and the focal length of the first lens group is f1, the following formula 0.25 <f1 / ΣD <0.4
The relay optical system according to claim 1, wherein the following condition is satisfied. The first lens group has a front group having a weak positive or negative refractive power, and a rear group having a positive refractive power, arranged in order from the optical path dividing element side,
The front group includes a single meniscus lens having a concave surface facing the optical path dividing element, or a meniscus cemented lens as a whole with the concave surface facing the optical path dividing element. The relay optical system according to 1 or 2. The focal length of the front group of the first lens group is f11, the distance from the rear focal position (pupil position) of the objective lens to the most specimen-side surface of the front group is DP, and the most specimen of the front group When the radius of curvature of the surface on the side is r1, the following expression f1 / | f11 | <0.7
−1.2 <r1 / DP <−0.4
The relay optical system according to claim 3, wherein the following condition is satisfied. Wherein the first lens group, the refractive index at the d-line as a nd _1, when the Abbe number was _{νd 1, nd 1 <1.6,} νd 1> at least a convex lens using glass material which satisfies the condition of 65 Have
When the focal length of the first lens group is f1, and the focal length of the convex lens of the first lens group is f1P,
0.25 <f1P / f1 <0.5
The relay optical system according to claim 1, wherein the following condition is satisfied. The third lens group includes at least one convex lens using a glass material that satisfies the conditions of nd ₃ <1.6 and νd ₃ > 65, where the refractive index for d-line is nd ₃ and the Abbe number is νd _3. Have
When the focal length of the third lens group is f3 and the focal length of the convex lens of the third lens group is f3P,
0.4 <f3P / f3 <1.5
The relay optical system according to claim 1, wherein the following condition is satisfied.

Images