JP2008197190A - Microscope photographic optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microscope photographic optical system designed so that size and cost are reduced, even if conditions for an intermediate lens barrel length is changed at reduction magnification, a decrease in a quantity of ambient light and occurrence of shading are suppressed and occurrence of aberration is also suppressed, and system performance can be improved according to the various microscope applications. <P>SOLUTION: The microscope photographic optical system includes, in order from the object side: an infinity correction type objective lens 1; an imaging lens group 2 forming an intermediate image from a luminous flux from the objective lens 1; and a relay optical system 3 for image forming the luminous flux from the imaging lens group 2. The imaging lens group 2 has a front group 21 (21" and 21"') and a rear group 22 (21" and 21"') with the intermediate image position between them. The microscope photographic optical system is composed so as to be replaceable as an imaging lens group 2 (2" and 2"') in which the composing conditions are differed so that according to a change in the pupil position of the objective lens 1, the incident pupil position IP1 of the objective lens 1 and the position of the incident pupil IP3 of a relay optical system 3 are substantially conjugate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a microscope photographing optical system for guiding an image of an observation object to photographing means such as an image pickup device such as a CCD in microscope observation.

  Conventionally, in a microscopic optical system, in general, light from an observation object is once formed as an intermediate image via an objective optical system or an objective optical system and an imaging lens, and then re-imaged on an imaging surface via a relay system. In addition, the image of the re-imaged observation object is picked up via the image sensor.

By the way, in the photographing optical system configured to re-image the intermediate image once formed through the relay system as described above, the exit pupil of the objective lens becomes smaller as the magnification of the photographing optical system becomes a reduction magnification. The angle of the principal ray emitted from the relay system with respect to the optical axis changes greatly due to the change in the length of the intermediate lens barrel, which varies depending on the objective lens replacement, microscope application, etc., and does not match the entrance pupil position of the relay system. Is likely to change. For this reason, there is a problem that peripheral light quantity is insufficient and shading is likely to occur on an image pickup device such as a CCD.
However, conventionally, for example, optical systems described in Patent Documents 1 and 2 have been proposed as microscope optical systems that solve such problems.
Japanese Patent No. 2990871 Japanese Patent Application Laid-Open No. 07-281091

The optical system described in Patent Document 1 has a configuration including an optical system that relays an intermediate image by the objective optical system to a detection surface (that is, an imaging surface), and changes in magnification of the objective optical system or the intermediate zoom system An optical element that conjugates the entrance pupil of the relay optical system to the entrance pupil of the objective optical system at an intermediate image in the optical system or a position in the vicinity thereof so that the imaging device side becomes telecentric even if the exit pupil position changes. It is configured to be replaceable.
That is, in the optical system described in Patent Document 1, even if the magnification of the photographic optical system is changed, the deviation of the pupil conjugate position arranged in the vicinity of the intermediate image, that is, the exit pupil position of the objective optical system and the relay optical system By exchanging the optical element for correcting the positional deviation with respect to the entrance pupil position, it is configured such that the peripheral light quantity is insufficient and shading hardly occurs on the image pickup element such as a CCD.

The optical system described in Patent Document 2 includes an objective optical system that forms an intermediate image in the optical system and a relay optical system that forms a final image, and the optical system is provided between the objective lens system and the relay optical system. A variable magnification optical system in which a plurality of variable magnification lens groups can be switched is provided, and the conjugate relationship of the pupil is maintained in the variable magnification optical system.
Further, the optical system described in Patent Document 2 maintains the pupil conjugate relationship of the variable power optical system even when the variable power lens group is switched, so that distortion caused by replacement of the variable power lens, lack of peripheral light amount, and the like do not occur. In addition, the configuration satisfies a predetermined conditional expression.

However, even in the photographing optical systems configured as described in Patent Documents 1 and 2, when the fluctuation range of the intermediate lens barrel length is around 100 mm, the aberration tends to deteriorate.
In the microscope observation, the length of the intermediate lens barrel constituting the microscope observation optical system can be changed by about 100 to 200 mm due to diversification of applications to be observed.
For example, when combined with a fluorescent illumination optical system and a thermostat unit for thermostating an objective lens or the like for cell culture, the intermediate lens barrel length of the microscope observation optical system changes by about 100 mm.

Here, if the length of the intermediate lens barrel is fixed to the longest intermediate lens barrel length in various applications, the microscope imaging optical system is configured to maintain the pupil conjugate relationship between the objective lens and the relay lens. Even when observed by an application, it is possible to prevent the peripheral light amount from being insufficient, shading, or the like.
However, this is not preferable because the microscope apparatus itself becomes large.

It is also conceivable that the entire photographing optical system is configured separately including the relay optical system so as to maintain the pupil conjugate relationship for each different intermediate lens barrel.
However, as the magnification of the photographic optical system becomes a reduction magnification, the focal length of the imaging lens becomes shorter, and as described above, the deviation between the exit pupil position of the objective lens and the entrance pupil position of the relay optical system increases. As the shading and the decrease in the amount of peripheral light increase, the lens configuration of the relay optical system tends to be complicated. In addition, it is difficult to take a sufficient rear focal length of the relay optical system.
For this reason, if the entire imaging optical system is configured separately including the relay optical system so as to maintain the pupil conjugate relationship for each different intermediate lens barrel, the cost for constructing a system that can handle various applications is extremely high. This is not preferable.

  In this way, conventional microscopic optical systems are adapted to various applications, especially when scaling to a reduction ratio, so that shading and lack of peripheral light quantity do not occur without increasing the size and cost. It was difficult to do.

  The present invention has been made in view of the above-described conventional problems, and is small in size and low in cost. Even if the length of the intermediate lens barrel is changed at the reduction magnification, the reduction in the amount of peripheral light and the occurrence of shading are suppressed, and aberrations are reduced. An object of the present invention is to provide a microscope photographing optical system capable of suppressing the occurrence and improving the system performance according to various microscope applications.

  In order to achieve the above object, a microscope optical system according to the present invention includes, in order from the object side, an infinitely corrected objective lens, an imaging lens group that forms an intermediate image from a light beam from the objective lens, and the imaging A relay optical system for imaging a light beam from the lens group, the imaging lens group having a front group and a rear group across an intermediate image position, and according to a change in a pupil position of the objective lens It is characterized in that it is configured to be interchangeable as an imaging lens group having different configuration conditions so that the entrance pupil position of the objective lens and the entrance pupil position of the relay optical system are substantially conjugate. .

  In the microscopic optical system of the present invention, when the pupil position of the objective lens changes, the connection is made so that the entrance pupil position of the objective lens and the entrance pupil of the relay optical system are substantially conjugate. It is preferable that the image lens group is configured so that the combination of lenses constituting the image forming lens group can be changed.

  In the microscopic optical system of the present invention, when the pupil position of the objective lens changes, the connection is made so that the entrance pupil position of the objective lens and the entrance pupil of the relay optical system are substantially conjugate. It is preferable that the image lens group is configured to be able to change a distance between predetermined lenses constituting the imaging lens group.

  In the microscopic optical system of the present invention, it is preferable that the imaging lens group is composed of an afocal optical system.

  Further, in the microscopic optical system of the present invention, the imaging lens group moves the at least one lens group constituting the afocal optical system in the optical axis direction, thereby obtaining the entrance pupil position of the objective lens. It is preferable that the entrance pupil position of the relay optical system is substantially conjugate.

  In the microscopic optical system of the present invention, it is preferable that the imaging lens group is further configured to have a zooming action.

  In the microscopic optical system of the present invention, the relay optical system includes a plurality of lens groups, and an entrance pupil position of the relay optical system is disposed between the imaging lens group and the relay optical system. It is preferable.

In the microscopic optical system of the present invention, the focal length of the relay optical system is F1, the focal length of the entire system is F, the variation of the pupil position of the objective lens is ΔD, and from the most image side in the relay optical system. It is preferable that the following conditional expressions (1) to (3) are satisfied, where d is the distance to the final image plane and L0 is the total length from the imaging lens group to the final image plane.
0.2 ≦ ΔD / L0 ≦ 0.4 (1)
0.4 ≦ | F1 / F | ≦ 0.9 (2)
0.5 ≦ F1 / d ≦ 0.8 (3)

  According to the present invention, for example, even if the intermediate lens barrel length varies greatly according to various applications in the reduction magnification, the objective optical system can be simply changed by changing the configuration of the imaging lens, such as replacing the imaging lens unit. The exit pupil of the relay optical system can be made almost coincident with the entrance pupil position of the relay optical system, so that the reduction of the peripheral light amount and the occurrence of shading can be suppressed, and the relay optical system can be made common, thereby reducing the cost. Thus, a microscope photographing optical system capable of improving the system performance according to various microscope applications can be obtained.

When the above conditional expressions (1) to (3) are satisfied, the distance between the objective lens and the imaging lens group is ΔD, and it is configured with different imaging lens groups and a common relay optical system. Aberration performance and the principal ray angle on the image plane can be relaxed (the exit pupil position can be increased).
If the lower limit of conditional expression (1) is not reached, the total length of the optical system becomes long, which is not preferable. In addition, the chief ray height at the intermediate image position becomes high, and it becomes difficult to correct off-axis coma and field curvature.
On the other hand, if the upper limit value of conditional expression (1) is exceeded, the total length of the relay optical system becomes too short, and an appropriate number of lenses cannot be arranged, so that aberration correction deteriorates. Or the back focus to the CCD camera which is an image sensor cannot be secured.
If the lower limit value of conditional expression (2) is not reached, the pupil relay magnification is reduced and the principal ray angle incident on the relay optical system becomes too large, making it difficult to correct off-axis aberrations.
On the other hand, if the upper limit value of conditional expression (2) is exceeded, the axial ray height in the relay optical system becomes larger and it becomes difficult to correct spherical aberration.
If the lower limit of conditional expression (3) is not reached, the principal ray angle on the image plane becomes larger and shading occurs, or the amount of peripheral light is insufficient, which is not preferable.
On the other hand, if the upper limit value of conditional expression (3) is exceeded, it is difficult to ensure back focus up to the image sensor.

First Embodiment FIGS. 1A and 1B are schematic configuration diagrams along the optical axis of a microscope photographing optical system according to a first embodiment of the present invention. 2A to 2C are schematic configuration diagrams along the optical axis of a conventional microscopic optical system according to a comparative example of the present invention. In FIGS. 1 and 2, reference numeral 4 denotes an image sensor disposed at a position where the microscope imaging optical system finally forms an image of the observation object.
As shown in FIG. 1, the microscopic optical system according to the first embodiment includes an infinity correction objective lens 1, an imaging lens group 2, and a relay optical system 3 in order from the object side.
The imaging lens group 2 includes a front group 21 and a rear group 22, and is configured to form an intermediate image of the observation object at a predetermined position P1 sandwiched between the front group 21 and the rear group 22.
The rear group 22 is configured to emit a divergent light beam incident through the intermediate image position P1 as a parallel light beam, and the imaging lens group 2 is configured by a substantially afocal optical system.
In FIG. 1, S denotes an aperture stop disposed at the intermediate image position P1.

The relay optical system 3 is configured to form an image of the light flux from the imaging lens group 2 on the surface of the image sensor 4.
In the present application, for convenience of explanation, these configurations are also substantially the same in the imaging optical system of the comparative example.

Here, as shown in FIGS. 1A and 1B, the microscopic optical system according to the first embodiment is different from the microscopic optical system of the comparative example shown in FIG. In accordance with the change in the pupil position of the objective lens 1, the imaging lens group 2 ″ having different configuration conditions so that the pupil position of the objective lens 1 and the position of the entrance pupil of the relay optical system 3 are substantially conjugate. 2 ′ ″ are configured to be exchangeable.
This point will be described in detail below using a comparative example.

  In the microscopic optical system of the comparative example shown in FIG. 2A, an intermediate lens barrel having an intermediate lens length L1 is used between the objective lens 1 and the imaging lens group 2. 2A, the exit pupil position OP1 of the objective lens 1 and the entrance pupil position IP3 of the relay optical system 3 substantially coincide at the position P2 (that is, the objective lens 1). The pupil (here, the entrance pupil IP1) is substantially conjugate with the entrance pupil IP3 of the relay optical system 3), and the principal ray from the relay optical system 3 is substantially parallel to the optical axis so that the imaging element 4 It is comprised so that it may inject into a surface. The exit pupil position OP1 is located between the imaging lens group 2 and the relay optical system 3.

  Here, in the microscopic optical system of the comparative example shown in FIG. 2A, it is assumed that the intermediate barrel length is changed from L1 to L2 by exchanging the intermediate barrel. Then, as shown in FIG. 2B, the exit pupil position OP1 of the objective lens 1 changes (here, the exit pupil position OP1 moves into the relay optical system 3). As a result, the exit pupil position OP1 of the objective lens 1 does not coincide with the entrance pupil position IP3 when the principal ray from the relay optical system 3 is parallel to the optical axis. For this reason, the principal ray from the relay optical system 3 changes to a state inclined by a predetermined amount with respect to the optical axis, and is incident on the surface of the image pickup device 4 obliquely.

Also, here, the main optical system from the relay optical system 3 when the focal length of the front group 21 constituting the imaging lens group 2 is different from the microscopic optical system of the comparative example shown in FIG. The relationship between the angle of the light beam and the angle with respect to the optical axis will be described with reference to FIGS.
FIG. 2 (c) shows that the focal length of the front group in the imaging lens group is longer and the focal length of the rear group is substantially the same as in the comparative example of the microscopic optical system shown in FIG. 2 (b). The structural example of the comprised microscope imaging optical system is shown.
As shown in FIG. 2C, the focal length of the front group 21 ′ constituting the imaging lens group 2 ′ is longer than that in FIG. Even if the length is changed from L1 to L2, the exit pupil position OP1 can be easily matched with the entrance pupil position IP3 when the principal ray from the relay optical system 3 is parallel to the optical axis.
On the other hand, as shown in FIG. 2 (b), the focal length of the front group 21 constituting the imaging lens group 2 is shorter than that of FIG. 2 (b). When the lens barrel length is changed from L1 to L2, the exit pupil position OP1 is likely to be greatly shifted from the entrance pupil position IP3 when the principal ray from the relay optical system 3 is parallel to the optical axis. As described above, the principal ray from the relay optical system 3 is inclined by a predetermined amount and easily enters the surface of the image sensor 4. As a result, problems such as shading, insufficient amount of peripheral light, and coloring occur on the surface of the image sensor 4.

  Therefore, in the microscopic optical system of the first embodiment, as shown in FIGS. 1A and 1B, the pupil position of the objective lens 1 (incidence pupil position IP1) according to the change of the pupil position of the objective lens 1. And an imaging lens group 2 (2 ″, 2 ″ ′) configured so that the entrance pupil position IP3 of the relay optical system 3 is substantially conjugate with each other.

  For example, in the configuration example of FIG. 1A, the exit pupil position OP1 of the objective lens 1 and the entrance pupil position IP3 of the relay optical system 3 substantially coincide (that is, the pupil of the objective lens (in this case, the entrance pupil IP1)). Is coupled to the entrance pupil IP3 of the relay optical system 3) so that the chief ray from the relay optical system 3 is incident on the surface of the image pickup device 4 substantially parallel to the optical axis. A front group 21 ″ and a rear group 22 ″ of the image lens group 2 ″ are configured.

Here, it is assumed that the pupil position (incidence pupil position) of the objective optical system is changed to the position shown in FIG. In other words, it is assumed that the intermediate lens barrel length is shortened by the predetermined amount Lx.
At this time, in the microscopic optical system of the first embodiment, the pupil position of the objective lens 1 (here, the entrance pupil position IP1) and the entrance pupil position IP3 of the relay optical system 3 according to the change in the pupil position of the objective lens 1. Can be replaced with an imaging lens group 2 ″ ′ composed of a front group 21 ″ ′ and a rear group 22 ″ ′ with the intermediate imaging position P1 interposed therebetween (FIG. 1B). For this reason, the exit pupil position OP1 of the objective lens 1 is made to substantially coincide with the entrance pupil position of the relay optical system 3, and the principal ray from the relay optical system 3 is made substantially parallel to the optical axis so that the image pickup device is obtained. 4 can be made incident.
As a result, it is possible to suppress the occurrence of shading, lack of peripheral light quantity, coloring, and the like on the surface of the image sensor 4.

According to the microscope photographing optical system of the first embodiment, when the intermediate lens barrel length is changed, the imaging lens is used to suppress the occurrence of shading, insufficient peripheral light amount, coloring, etc. on the surface of the image sensor 4. Since it is sufficient to replace the group 2, the relay optical system 3 can be made common and the cost can be reduced.
For this reason, according to the microscope photographing optical system of the first embodiment, a microscope system corresponding to various applications can be configured at low cost, and the system performance can be improved. For example, a constant temperature unit of an objective lens when combined with an incubator, a fluorescent floodlight, and the like can be combined. Furthermore, it is possible to combine other relay optical systems with different magnifications with a common relay optical system, or to combine the afocal zoom optical system with other photographing magnifications.

In the configuration example of FIG. 1, the relay optical system 3 having a configuration in which the entrance pupil position IP3 is located between the relay optical system 3 and the imaging lens group 2 is used. The relay optical system 3 used in the photographing optical system may be configured such that the entrance pupil position IP3 is located inside the relay optical system 3.
If the entrance pupil position IP3 of the relay optical system 3 is located between the relay optical system 3 and the imaging lens group 2, a diaphragm for phase difference observation can be arranged at that position, or the pupil Even if a parallel plate for modulation is arranged, there is an advantage that the pupil position does not change.

  Further, as described above, the imaging lens group 2 in FIG. 1 is configured by a substantially afocal optical system. For this reason, it becomes easy to optically connect with the subsequent relay lens 3. Note that the imaging lens group 2 in the microscopic optical system of the present invention can be applied even if it is not necessarily composed of an afocal optical system.

In addition to the configuration of the first embodiment, the imaging lens group 2 of the present invention may be configured such that the imaging lens group 2 can perform zooming by switching the configuration.
Furthermore, in addition to the configuration of the first embodiment, the imaging optical system of the present invention includes the imaging lens group 2 as an afocal zoom lens having an intermediate image inside and an exit pupil outside on the exit side. May be.

Second Embodiment FIGS. 3A to 3C are schematic configuration diagrams along the optical axis of a microscope photographing optical system according to a second embodiment of the present invention.
In the microscopic optical system of the second embodiment, the imaging lens group 2 is configured to function as a magnification unit that can perform magnification by switching its configuration.
FIG. 3A shows a configuration in which the reference imaging lens group 2 is combined. FIG. 3B shows a configuration example in which an imaging lens group 2 ′ that changes the magnification from the magnification in the reference state to the reduction magnification is combined. FIG. 3 (c) shows a configuration example in which an imaging lens group 2 ″ that changes the magnification from the magnification in the standard state to the magnification is combined.
In the microscopic optical system of the second embodiment, the exit pupil position of the objective lens 1 and the entrance pupil position of the relay lens 3 are the same in any configuration in which any imaging lens group 2 is combined, and the conjugate relationship of the pupils. Each objective lens group 2 is configured so that is maintained.
Other configurations and operational effects are almost the same as those of the microscope photographing optical system according to the first embodiment shown in FIG.

In the microscopic optical system of the second embodiment, the imaging lens group is configured as a variable power unit that can be changed according to the magnification. However, it may be configured as a variable focal length afocal zoom optical system.
That is, it may be configured such that zooming can be performed by moving at least one of the front group 21 and the rear group 22 constituting the imaging lens group 2 along the optical axis.

In the microscopic optical system of each embodiment of the present invention, the focal length of the relay optical system is F1, the focal length of the entire system is F, the variation of the pupil position of the objective lens is ΔD, and the relay optical system When the distance from the image side surface to the final image surface is d and the total length from the imaging lens group to the final image surface is L0, the following conditional expressions (1) to (3) are satisfied.
0.2 ≦ ΔD / L0 ≦ 0.4 (1)
0.4 ≦ | F1 / F | ≦ 0.9 (2)
0.5 ≦ F1 / d ≦ 0.8 (3)

Next, embodiments of the present invention will be described with reference to the drawings.
Example 1
FIG. 4 is a cross-sectional view along the optical axis showing a schematic configuration of the main part of the microscopic optical system according to Example 1 of the present invention, where (a) is a state corresponding to FIG. (State 1) and (b) show states corresponding to FIG. 1 (b) (hereinafter referred to as state 2). FIG. 5 is a graph showing the spherical aberration, field curvature, distortion, and coma aberration of the microscopic optical system of FIG. 4, where (a) shows the aberration in state 1 and (b) shows the aberration in state 2. Respectively. For convenience, the infinity corrected objective lens is not shown.
The microscopic optical system of Example 1 includes an infinity correction objective lens, an imaging lens group 2 and a relay optical system 3 (not shown) in order from the object side.
The imaging lens group 2 includes a front group 21 and a rear group 22, and is configured to form an intermediate image of the observation object at a predetermined position P1 sandwiched between the front group 21 and the rear group 22.
The rear group 22 is configured to emit a divergent light beam incident through the intermediate image position P1 as a parallel light beam, and the imaging lens group 2 includes a substantially afocal optical system.
In FIG. 4, S is an aperture stop arranged at the intermediate image position P1.
The relay optical system 3 is configured to image the light flux from the imaging lens group 2 on the surface IM of the image sensor.
In addition, the imaging lens group 2 is configured so that the pupil position (incidence pupil position IP1) of the objective lens and the entrance pupil position IP3 of the relay optical system 3 are substantially conjugate with the change in the pupil position of the objective lens. The imaging lens groups 2 ″, 2 ′ ″ having different configuration conditions are configured to be interchangeable.

Specifically, in the state shown in FIG. 4A, the exit pupil position OP1 of the objective lens and the entrance pupil position IP3 of the relay optical system 3 substantially coincide with each other, and the principal ray from the relay optical system 3 is relative to the optical axis. The front group 21 ″ and the rear group 22 ″ of the imaging lens group 2 ″ are configured so as to be substantially parallel and incident on the surface of the image pickup device 4.
Further, when the pupil position (incidence pupil position IP1) of the objective optical system is changed to the position shown in FIG. 4B by exchanging the intermediate lens barrel and the intermediate lens barrel length is shortened, the pupil position of the objective lens is changed. The front group 21 ″ ′ and the rear group sandwiching the intermediate imaging position P1 so that the pupil position (incidence pupil position IP1) of the objective lens and the entrance pupil position IP3 of the relay optical system 3 are substantially conjugate with each other according to the change. It can be exchanged for an imaging lens group 2 ″ ′ composed of 22 ″ ′.

  In the state shown in FIG. 4A, the front lens group 21 ″ of the imaging lens group 2 ″ includes, in order from the object side, a cemented lens of a biconvex lens L211 and a negative meniscus lens L212 having a concave surface facing the object side. It is composed of a cemented lens composed of a positive meniscus lens L213 having a convex surface facing the object side and a negative meniscus lens L214 having a convex surface facing the object side. Further, the rear group 22 ″ includes a positive meniscus lens L221 having a convex surface directed toward the object side.

  On the other hand, in the state shown in FIG. 4B, the front group 21 ′ ″ of the imaging lens group 2 ′ ″ includes, in order from the object side, a biconvex lens L211 and a negative meniscus lens L212 having a concave surface facing the object side. The lens includes a cemented lens and a cemented lens of a biconvex lens L213 ′ and a positive meniscus lens L214 ′ having a concave surface facing the object side. Further, the rear group 22 ′ ″ has a cemented lens of a plano-convex lens L221 ′ having a convex surface on the object side and a flat surface on the image side and a plano-concave lens L222 having a flat surface on the object side and a concave surface on the image side, and a convex surface facing the object side. And a positive meniscus lens L223.

  4A and 4B, the relay optical system 3 includes, in order from the object side, a negative meniscus lens L31 having a concave surface on the object side and a positive surface having a concave surface on the object side. A cemented lens with a meniscus lens L32, a cemented lens with a biconcave lens L33 and a biconvex lens L34, a cemented lens with a biconvex lens L35 and a negative meniscus lens L36 having a concave surface on the object side, and a convex surface on the object side. It comprises a negative meniscus lens L37.

Next, numerical data of optical members constituting the microscopic optical system of Example 1 are shown. In the numerical data, S ₁ , S ₂ ,... Are surface numbers of optical members constituting the microscope photographing optical system, r ₁ , r ₂ ,... Are curvature radii of optical members constituting the microscope photographing optical system, d ₁ , D ₂ ,... _Are interplanar spacings, n _d1 , n _d2 ,... Refractive index at the d-line of an optical member constituting the microscope photographing optical system, ν _d1 , ν _d2,. The Abbe number at d line. These symbols are common to the following embodiments.

Numerical data 1-1 (Example 1: State 1)
S ₁ (objective pupil position) r ₁ = ∞ d ₁ = 20.000
S ₂ (with objective lens barrel) r ₂ = ∞ d ₂ = 220.000
S ₃ (imaging lens front group) r ₃ = 234.906 d ₃ = 6.100 n _d3 = 1.48749 ν _d3 = 70.23
S ₄ r ₄ = -64.885 d ₄ = 4.000 n _d4 = 1.7185 ν _d4 = 33.52
S ₅ r ₅ = −101.900 d ₅ = 16.843
S ₆ r ₆ = 59.353 d ₆ = 7.356 n _d6 = 1.48749 ν _d6 = 70.23
S ₇ r ₇ = 147.577 d ₇ = 5.499 n _d7 = 1.51633 ν _d7 = 64.14
S ₈ r ₈ = 116.639 d ₈ = 81.999
S ₉ (intermediate image position) r ₉ = ∞ d ₉ = 61.648
S ₁₀ (back lens group) r ₁₀ = 15.718 d ₁₀ = 7.728 n _d10 = 1.7552 ν _d10 = 27.51
S ₁₁ r ₁₁ = 20.892 d ₁₁ = 4.000
S ₁₂ (pupil conjugate position) r ₁₂ = ∞ d ₁₂ = 3.846
S ₁₃ (Relay lens group) r ₁₃ = -9.801 d ₁₃ = 9.538 n _d13 = 1.7725 ν _d13 = 49.6
S ₁₄ r ₁₄ = -78.026 d ₁₄ = 6.308 n _d14 = 1.497 ν _d14 = 81.54
S ₁₅ r ₁₅ = -13.819 d ₁₅ = 1.319
S ₁₆ r ₁₆ = −150.852 d ₁₆ = 2.008 n _d16 = 1.741 ν _d16 = 52.64
S ₁₇ r ₁₇ = 20.314 d ₁₇ = 6.032 n _d17 = 1.43875 ν _d17 = 94.93
S ₁₈ r ₁₈ = -35.441 d ₁₈ = 0.300
S ₁₉ r ₁₉ = 24.989 d ₁₉ = 7.912 n _d19 = 1.43875 ν _d19 = 94.93
S ₂₀ r ₂₀ = -19.798 d ₂₀ = 2.045 n _d20 = 1.7725 ν _d20 = 49.6
S ₂₁ r ₂₁ = -42.410 d ₂₁ = 0.163
S ₂₂ r ₂₂ = 18.795 d ₂₂ = 9.636 n _d22 = 1.618 ν _d22 = 63.33
S ₂₃ r ₂₃ = 15.659 d ₂₃ = 65.720
S ₂₄ (imaging surface) r ₂₄ = ∞

Numerical data 1-2 (Example 1: State 2)
S ₁ (objective pupil position) r ₁ = ∞ d ₁ = 20.000
S ₂ (with objective lens barrel) r ₂ = ∞ d ₂ = 120.000
S ₃ (imaging lens front group) r ₃ = 234.906 d ₃ = 6.100 n _d3 = 1.48749 ν _d3 = 70.23
S ₄ r ₄ = -64.885 d ₄ = 4.000 n _d4 = 1.7185 ν _d4 = 33.52
S ₅ r ₅ = −101.900 d ₅ = 62.490
_{S 6 r 6 = 62.597 d 6} = 4.292 n d6 = 1.48749 ν d6 = 70.23
S ₇ r ₇ = −728.204 d ₇ = 3.500 n _d7 = 1.58267 ν _d7 = 46.42
_{S 8 r 8 = -304.389 d 8} = 50.862
S ₉ (intermediate image position) r ₉ = ∞ d ₉ = 49.669
S ₁₀ (imaging lens rear group) r ₁₀ = 17.686 d ₁₀ = 3.140 n _d10 = 1.618 ν _d10 = 63.33
S ₁₁ r ₁₁ = ∞ d ₁₁ = 3.0000 n _d11 = 1.48749 ν _d11 = 70.23
S ₁₂ r ₁₂ = 14.477 d ₁₂ = 0.500
S ₁₃ r ₁₃ = 14.539 d ₁₃ = 3.710 n _d13 = 1.72825 ν _d13 = 28.46
S ₁₄ r ₁₄ = 21.083 d ₁₄ = 3.910
S ₁₅ (pupil conjugate position) r ₁₅ = ∞ d ₁₅ = 3.846
S ₁₆ (relay lens group) r ₁₆ = −9.801 d ₁₆ = 9.538 n _d16 = 1.7725 ν _d16 = 49.6
S ₁₇ r ₁₇ = -78.026 d ₁₇ = 6.308 n _d17 = 1.497 ν _d17 = 81.54
S ₁₈ r ₁₈ = -13.819 d ₁₈ = 1.319
S ₁₉ r ₁₉ = -150.852 d ₁₉ = 2.008 n _d19 = 1.741 ν _d19 = 52.64
S ₂₀ r ₂₀ = 20.314 d ₂₀ = 6.032 n _d20 = 1.43875 ν _d20 = 94.93
S ₂₁ r ₂₁ = -35.441 d ₂₁ = 0.300
S ₂₂ r ₂₂ = 24.989 d ₂₂ = 7.912 n _d22 = 1.43875 ν _d22 = 94.93
S ₂₃ r ₂₃ = -19.798 d ₂₃ = 2.045 n _d23 = 1.7725 ν _d23 = 49.6
S ₂₄ r ₂₄ = -42.410 d ₂₄ = 0.163
_{S 25 r 25 = 18.795 d 25} = 9.636 n d25 = 1.618 ν d25 = 63.33
S ₂₆ r ₂₆ = 15.659 d ₂₆ = 65.720
S ₂₇ (imaging surface) r ₂₇ = ∞

Example 2
FIG. 6 is a cross-sectional view along the optical axis showing a schematic configuration of the main part of the microscopic optical system according to the second embodiment of the present invention, in which (a) is a state corresponding to FIG. ) And (b) respectively show states (state 2) corresponding to FIG. 1 (b). FIG. 7 is a graph showing the spherical aberration, field curvature, distortion, and coma aberration of the microscopic optical system of FIG. 6, where (a) shows the aberration in state 1 and (b) shows the aberration in state 2. Respectively. For convenience, the infinity corrected objective lens is not shown.
The microscopic optical system of Example 2 includes an infinity correction objective lens, an imaging lens group 2, and a relay optical system 3 (not shown) in order from the object side.
The imaging lens group 2 includes a front group 21 and a rear group 22, and is configured to form an intermediate image of the observation object at a predetermined position P1 sandwiched between the front group 21 and the rear group 22.
The rear group 22 is configured to emit a divergent light beam incident through the intermediate image position P1 as a parallel light beam, and the imaging lens group 2 includes a substantially afocal optical system.
In FIG. 6, S denotes an aperture stop disposed at the intermediate image position P1.
The relay optical system 3 is configured to image the light flux from the imaging lens group 2 on the surface IM of the image sensor.
In addition, the imaging lens group 2 is configured so that the pupil position (incidence pupil position IP1) of the objective lens and the entrance pupil position IP3 of the relay optical system 3 are substantially conjugate with the change in the pupil position of the objective lens. The imaging lens groups 2 ″, 2 ′ ″ having different configuration conditions are configured to be interchangeable.

Specifically, in the state shown in FIG. 6A, the exit pupil position OP1 of the objective lens and the entrance pupil position IP3 of the relay optical system 3 are substantially coincident, and the principal ray from the relay optical system 3 is relative to the optical axis. The front group 21 ″ and the rear group 22 ″ of the imaging lens group 2 ″ are configured so as to be substantially parallel and incident on the surface of the image pickup device 4.
When the intermediate lens barrel is replaced and the pupil position (incidence pupil position IP1) of the objective optical system is changed to the position shown in FIG. 6B and the intermediate lens barrel length is shortened, the pupil position of the objective lens is changed. The front group 21 ″ ′ and the rear group sandwiching the intermediate imaging position P1 so that the pupil position (incidence pupil position IP1) of the objective lens and the entrance pupil position IP3 of the relay optical system 3 are substantially conjugate with each other according to the change. It can be exchanged for an imaging lens group 2 ″ ′ composed of 22 ″ ′.

  In the state shown in FIG. 6A, the front lens group 21 ″ of the imaging lens group 2 ″ includes, in order from the object side, a cemented lens of a biconvex lens L211 and a negative meniscus lens L212 having a concave surface facing the object side. It is composed of a cemented lens of a biconvex lens L213 ′ and a biconcave lens L214 ″. The rear group 22 ″ is composed of a positive meniscus lens L221 having a convex surface facing the object side.

  On the other hand, in the state shown in FIG. 6B, the front group 21 ′ ″ of the imaging lens group 2 ′ ″ includes, in order from the object side, a biconvex lens L211 and a negative meniscus lens L212 having a concave surface facing the object side. It is composed of a cemented lens, a cemented lens of a biconvex lens L213 ′ and a negative meniscus lens L214 ′ ″ having a concave surface facing the object side. The rear group 22 ′ ″ has a convex surface on the object side in order from the object side. And a cemented lens of a plano-convex lens L221 ′ having a flat image side, a plano-concave lens L222 having a flat object side and a concave surface on the image side, and a positive meniscus lens L223 having a convex surface facing the object side.

  6A and 6B, the relay optical system 3 includes, in order from the object side, a negative meniscus lens L31 having a concave surface on the object side and a positive surface having a concave surface on the object side. A cemented lens of the meniscus lens L32, a cemented lens of the biconcave lens L33 and the biconvex lens L34, a cemented lens of the biconvex lens L35 and the negative meniscus lens L36 having a concave surface facing the object side, and a convex surface facing the object side. And a positive meniscus lens L37 ′.

Next, numerical data of optical members constituting the microscopic optical system of Example 2 are shown.
Numerical data 2-1 (Example 2: State 1)
S ₁ (objective pupil position) r ₁ = ∞ d ₁ = 20.000
S ₂ (with objective lens barrel) r ₂ = ∞ d ₂ = 220.000
S ₃ (imaging lens front group) r ₃ = 234.906 d ₃ = 6.100 n _d3 = 1.48749 ν _d3 = 70.23
S ₄ r ₄ = -64.885 d ₄ = 4.000 n _d4 = 1.7185 ν _d4 = 33.52
S ₅ r ₅ = −101.900 d ₅ = 24.111
S ₆ r ₆ = 54.794 d ₆ = 7.034 n _d6 = 1.48749 ν _d6 = 70.23
S ₇ r ₇ = −53.602 d ₇ = 5.404 n _d7 = 1.51633 ν _d7 = 64.14
S ₈ r ₈ = 110.695 d ₈ = 81.030
S ₉ (intermediate image position) r ₉ = ∞ d ₉ = 67.736
S ₁₀ (back lens group) r ₁₀ = 16.528 d ₁₀ = 8.053 n _d10 = 1.7552 ν _d10 = 27.51
S ₁₁ r ₁₁ = 20.401 d ₁₁ = 4.309
S ₁₂ (pupil conjugate position) r ₁₂ = ∞ d ₁₂ = 3.301
S ₁₃ (relay lens group) r ₁₃ = -10.467 d ₁₃ = 9.545 n _d13 = 1.7725 ν _d13 = 49.6
S ₁₄ r ₁₄ = -63.909 d ₁₄ = 6.392 n _d14 = 1.497 ν _d14 = 81.54
S ₁₅ r ₁₅ = -14.408 d ₁₅ = 1.440
S ₁₆ r ₁₆ = −63.790 d ₁₆ = 2.272 n _d16 = 1.741 ν _d16 = 52.64
S ₁₇ r ₁₇ = 25.476 d ₁₇ = 6.074 n _d17 = 1.43875 ν _d17 = 94.93
S ₁₈ r ₁₈ = -28.649 d ₁₈ = 0.300
S ₁₉ r ₁₉ = 30.011 d ₁₉ = 7.616 n _d19 = 1.43875 ν _d19 = 94.93
S ₂₀ r ₂₀ = -19.924 d ₂₀ = 2.000 n _d20 = 1.7725 ν _d20 = 49.6
S ₂₁ r ₂₁ = -42.478 d ₂₁ = 0.150
S ₂₂ r ₂₂ = 22.531 d ₂₂ = 9.919 n _d22 = 1.618 ν _d22 = 63.33
S ₂₃ r ₂₃ = 26.974 d ₂₃ = 53.216
S ₂₄ (imaging surface) r ₂₄ = ∞

Numerical data 2-2 (Example 2: State 2)
S ₁ (objective pupil position) r ₁ = ∞ d ₁ = 20.000
S ₂ (with objective lens barrel) r ₂ = ∞ d ₂ = 120.000
S ₃ (imaging lens front group) r ₃ = 234.906 d ₃ = 6.100 n _d3 = 1.48749 ν _d3 = 70.23
S ₄ r ₄ = -64.885 d ₄ = 4.000 n _d4 = 1.7185 ν _d4 = 33.52
S ₅ r ₅ = −101.900 d ₅ = 68.476
S ₆ r ₆ = 51.269 d ₆ = 6.196 n _d6 = 1.48749 ν _d6 = 70.23
S ₇ r ₇ = −63.016 d ₇ = 3.500 n _d7 = 1.72916 ν _d7 = 54.68
_{S 8 r 8 = -211.424 d 8} = 49.212
S ₉ (intermediate image position) r ₉ = ∞ d ₉ = 55.584
S ₁₀ (imaging lens rear group) r ₁₀ = 18.490 d ₁₀ = 3.140 n _d10 = 1.618 ν _d10 = 63.33
S ₁₁ r ₁₁ = ∞ d ₁₁ = 3.0000 n _d11 = 1.48749 ν _d11 = 70.23
S ₁₂ r ₁₂ = 15.055 d ₁₂ = 0.500
S ₁₃ r ₁₃ = 14.873 d ₁₃ = 4.047 n _d13 = 1.72825 ν _d13 = 28.46
S ₁₄ r ₁₄ = 19.733 d ₁₄ = 4.023
S ₁₅ (pupil conjugate position) r ₁₅ = ∞ d ₁₅ = 3.301
S ₁₆ (Relay lens group) r ₁₆ = -10.467 d ₁₆ = 9.545 n _d16 = 1.7725 ν _d16 = 49.6
S ₁₇ r ₁₇ = −63.909 d ₁₇ = 6.392 n _d17 = 1.497 ν _d17 = 81.54
S ₁₈ r ₁₈ = -14.408 d ₁₈ = 1.440
S ₁₉ r ₁₉ = -63.790 d ₁₉ = 2.272 n _d19 = 1.741 ν _d19 = 52.64
S ₂₀ r ₂₀ = 25.476 d ₂₀ = 6.074 n _d20 = 1.43875 ν _d20 = 94.93
S ₂₁ r ₂₁ = -28.649 d ₂₁ = 0.300
S ₂₂ r ₂₂ = 30.011 d ₂₂ = 7.616 n _d22 = 1.43875 ν _d22 = 94.93
S ₂₃ r ₂₃ = -19.924 d ₂₃ = 2.000 n _d23 = 1.7725 ν _d23 = 49.6
S ₂₄ r ₂₄ = -42.478 d ₂₄ = 0.150
_{S 25 r 25 = 22.531 d 25} = 9.919 n d25 = 1.618 ν d25 = 63.33
S ₂₆ r ₂₆ = 26.974 d ₂₆ = 53.216
S ₂₇ (imaging surface) r ₂₇ = ∞

Example 3
FIG. 8 is a cross-sectional view along the optical axis showing a schematic configuration of the main part of the microscopic optical system according to Example 3 of the present invention, where (a) is a state corresponding to FIG. ) And (b) respectively show states (state 2) corresponding to FIG. 1 (b). FIG. 9 is a graph showing the spherical aberration, field curvature, distortion, and coma aberration of the microscopic optical system of FIG. 8, where (a) shows aberrations in state 1 and (b) shows aberrations in state 2. Respectively. For convenience, the infinity corrected objective lens is not shown.
The microscopic optical system of Example 3 includes an infinity correction objective lens, an imaging lens group 2, and a relay optical system 3 (not shown) in order from the object side.
The imaging lens group 2 includes a front group 21 and a rear group 22, and is configured to form an intermediate image of the observation object at a predetermined position P1 sandwiched between the front group 21 and the rear group 22.
The rear group 22 is configured to emit a divergent light beam incident through the intermediate image position P1 as a parallel light beam, and the imaging lens group 2 includes a substantially afocal optical system.
In FIG. 8, S is an aperture stop disposed at the intermediate image position P1.
The relay optical system 3 is configured to image the light flux from the imaging lens group 2 on the surface IM of the image sensor.
In addition, the imaging lens group 2 is configured so that the pupil position (incidence pupil position IP1) of the objective lens and the entrance pupil position IP3 of the relay optical system 3 are substantially conjugate with the change in the pupil position of the objective lens. The imaging lens groups 2 ″, 2 ′ ″ having different configuration conditions are configured to be interchangeable.

Specifically, in the state shown in FIG. 8 (a), the exit pupil position OP1 of the objective lens and the entrance pupil position IP3 of the relay optical system 3 substantially coincide with each other, and the principal ray from the relay optical system 3 is relative to the optical axis. The front group 21 ″ and the rear group 22 ″ of the imaging lens group 2 ″ are configured so as to be substantially parallel and incident on the surface of the image pickup device 4.
Further, when the pupil position (incidence pupil position IP1) of the objective optical system is changed to the position shown in FIG. 8B by exchanging the intermediate lens barrel and the intermediate lens barrel length is shortened, the pupil position of the objective lens is changed. The front group 21 ″ ′ and the rear group sandwiching the intermediate imaging position P1 so that the pupil position (incidence pupil position IP1) of the objective lens and the entrance pupil position IP3 of the relay optical system 3 are substantially conjugate with each other according to the change. It can be exchanged for an imaging lens group 2 ″ ′ composed of 22 ″ ′.

  In the state shown in FIG. 8A, the front lens group 21 ″ of the imaging lens group 2 ″ includes, in order from the object side, a cemented lens of a biconvex lens L211 and a negative meniscus lens L212 having a concave surface facing the object side; It is composed of a cemented lens of a biconvex lens L213 ′ and a biconcave lens L214 ″. The rear group 22 ″ is composed of a positive meniscus lens L221 having a convex surface facing the object side.

  On the other hand, in the state shown in FIG. 8B, the front group 21 ′ ″ of the imaging lens group 2 ′ ″ includes, in order from the object side, a biconvex lens L211 and a negative meniscus lens L212 having a concave surface facing the object side. It is composed of a cemented lens, a cemented lens of a biconvex lens L213 ′ and a negative meniscus lens L214 ′ ″ having a concave surface facing the object side. The rear group 22 ′ ″ has a convex surface on the object side in order from the object side. And a cemented lens of a plano-convex lens L221 ′ having a flat image side, a plano-concave lens L222 having a flat object side and a concave surface on the image side, and a positive meniscus lens L223 having a convex surface facing the object side.

  8A and 8B, the relay optical system 3 includes, in order from the object side, a plano-concave lens L31 ′ having a concave surface on the object side and a plane on the image side and a convex surface on the object side and a convex surface on the image side. A cemented lens of a planoconvex lens L32 ′, a cemented lens of a biconcave lens L33 and a biconvex lens L34, a cemented lens of a biconvex lens L35 and a negative meniscus lens L36 having a concave surface facing the object side, and a biconvex lens L37 ″. It consists of

Next, numerical data of optical members constituting the microscopic optical system of Example 3 are shown.
Numerical data 3-1 (Example 3: State 1)
S ₁ (objective pupil position) r ₁ = ∞ d ₁ = 20.000
S ₂ (with objective lens barrel) r ₂ = ∞ d ₂ = 220.000
S ₃ (imaging lens front group) r ₃ = 234.906 d ₃ = 6.1 n _d3 = 1.48749 ν _d3 = 70.23
S ₄ r ₄ = -64.885 d ₄ = 4 n _d4 = 1.7185 ν _d4 = 33.52
S ₅ r ₅ = −101.900 d ₅ = 26.557
S ₆ r ₆ = 48.963 d ₆ = 7.1 n _d6 = 1.48749 ν _d6 = 70.23
S ₇ r ₇ = −51.717 d ₇ = 5.25 n _d7 = 1.51633 ν _d7 = 64.14
_{S 8 r 8 = 84.987 d 8} = 80.653
S ₉ (intermediate image position) r ₉ = ∞ d ₉ = 72.0133
S ₁₀ (imaging lens rear group) r ₁₀ = 15.272 d ₁₀ = 8.15 n _d10 = 1.7552 ν _d10 = 27.51
S ₁₁ r ₁₁ = 17.552 d ₁₁ = 4.15
S ₁₂ (pupil conjugate position) r ₁₂ = ∞ d ₁₂ = 3.4258
S ₁₃ (Relay lens group) r ₁₃ = -9.204 d ₁₃ = 9.4 n _d13 = 1.741 ν _d13 = 52.64
S ₁₄ r ₁₄ = ∞ d ₁₄ = 6.46 n _d14 = 1.497 ν _d14 = 81.54
S ₁₅ r ₁₅ = -13.282 d ₁₅ = 1.5068
S ₁₆ r ₁₆ = -72.689 d ₁₆ = 2.3 n _d16 = 1.741 ν _d16 = 52.64
S ₁₇ r ₁₇ = 23.944 d ₁₇ = 6.1 n _d17 = 1.43875 ν _d17 = 94.93
S ₁₈ r ₁₈ = -33.547 d ₁₈ = 0.3
S ₁₉ r ₁₉ = 27.204 d ₁₉ = 8.24 n _d19 = 1.43875 ν _d19 = 94.93
S ₂₀ r ₂₀ = -19.488 d ₂₀ = 2 n _d20 = 1.7725 ν _d20 = 49.6
S ₂₁ r ₂₁ = -59.577 d ₂₁ = 0.15
S ₂₂ r ₂₂ = 37.913 d ₂₂ = 7.96 n _d22 = 1.618 ν _d22 = 63.33
S ₂₃ r ₂₃ = -133.245 d ₂₃ = 48.1442
S ₂₄ (imaging surface) r ₂₄ = ∞

Numerical data 3-2 (Example 3: State 2)
S ₁ (objective pupil position) r ₁ = ∞ d ₁ = 20.000
S ₂ (with objective lens barrel) r ₂ = ∞ d ₂ = 120.000
S ₃ (imaging lens front group) r ₃ = 234.9061 d ₃ = 6.100 n _d3 = 1.48749 ν _d3 = 70.23
S ₄ r ₄ = -64.8854 d ₄ = 4.000 n _d4 = 1.7185 ν _d4 = 33.52
S ₅ r ₅ = −101.9 d ₅ = 68.672
S ₆ r ₆ = 50.1089 d ₆ = 7.240 n _d6 = 1.48749 ν _d6 = 70.23
S ₇ r ₇ = -77.2757 d ₇ = 3.500 n _d7 = 1.72916 ν _d7 = 54.68
S ₈ r ₈ = -371.269 d ₈ = 49.665
S ₉ (intermediate image position) r ₉ = ∞ d ₉ = 56.924
S ₁₀ (imaging lens rear group) r ₁₀ = 17.5826 d ₁₀ = 3.140 n _d10 = 1.618 ν _d10 = 63.33
S ₁₁ r ₁₁ = ∞ d ₁₁ = 3.0000 n _d11 = 1.48749 ν _d11 = 70.23
S ₁₂ r ₁₂ = 13.9098 d ₁₂ = 3.412
S ₁₃ r ₁₃ = 13.3327 d ₁₃ = 4.240 n _d13 = 1.72825 ν _d13 = 28.46
S ₁₄ r ₁₄ = 16.5691 d ₁₄ = 4.080
S ₁₅ (pupil conjugate position) r ₁₅ = ∞ d ₁₅ = 3.426
S ₁₆ (relay lens group) r ₁₆ = -9.2044 d ₁₆ = 9.440 n _d16 = 1.741 ν _d16 = 52.64
S ₁₇ r ₁₇ = ∞ d ₁₇ = 6.460 n _d17 = 1.497 ν _d17 = 81.54
_{S 18 r 18 = -13.2821 d 18} = 1.507
S ₁₉ r ₁₉ = -72.6888 d ₁₉ = 2.300 n _d19 = 1.741 ν _d19 = 52.64
S ₂₀ r ₂₀ = 23.9439 d ₂₀ = 6.100 n _d20 = 1.43875 ν _d20 = 94.93
S ₂₁ r ₂₁ = -33.5471 d ₂₁ = 0.300
S ₂₂ r ₂₂ = 27.2039 d ₂₂ = 8.240 n _d22 = 1.43875 ν _d22 = 94.93
S ₂₃ r ₂₃ = -19.4876 d ₂₃ = 2.000 n _d23 = 1.7725 ν _d23 = 49.6
S ₂₄ r ₂₄ = -59.5768 d ₂₄ = 0.150
_{S 25 r 25 = 37.9125 d 25} = 7.960 n d25 = 1.618 ν d25 = 63.33
S ₂₆ r ₂₆ = -133.245 d ₂₆ = 48.144
S ₂₇ (imaging surface) r ₂₇ = ∞

Example 4
FIG. 10 is a cross-sectional view along the optical axis showing the schematic configuration of the main part of the microscope optical system according to Example 4 of the present invention, where (a) is a state corresponding to FIG. ) And (b) respectively show states (state 2) corresponding to FIG. 1 (b). FIG. 11 is a graph showing the spherical aberration, field curvature, distortion, and coma aberration of the microscope photographing optical system of FIG. 10, where (a) shows the aberration in state 1 and (b) shows the aberration in state 2. Respectively. For convenience, the infinity corrected objective lens is not shown.
The microscope optical system of Example 4 includes an infinity correction objective lens, an imaging lens group 2, and a relay optical system 3 (not shown) in order from the object side.
The imaging lens group 2 includes a front group 21 and a rear group 22, and is configured to form an intermediate image of the observation object at a predetermined position P1 sandwiched between the front group 21 and the rear group 22.
The rear group 22 is configured to emit a divergent light beam incident through the intermediate image position P1 as a parallel light beam, and the imaging lens group 2 includes a substantially afocal optical system.
In FIG. 10, S is an aperture stop disposed at the intermediate image position P1.
The relay optical system 3 is configured to image the light flux from the imaging lens group 2 on the surface IM of the image sensor.
In addition, the imaging lens group 2 is configured so that the pupil position of the objective lens (incidence pupil position IP1) and the entrance pupil position IP3 of the relay optical system 3 are substantially conjugate with changes in the pupil position of the objective lens. The imaging lens groups 2 ″, 2 ′ ″ having different configuration conditions are configured to be interchangeable.

Specifically, in the state shown in FIG. 10A, the exit pupil position OP1 of the objective lens and the entrance pupil position IP3 of the relay optical system 3 substantially coincide with each other, and the principal ray from the relay optical system 3 is relative to the optical axis. The front group 21 ″ and the rear group 22 ″ of the imaging lens group 2 ″ are configured so as to be substantially parallel and incident on the surface of the image pickup device 4.
Further, when the intermediate lens barrel is replaced and the pupil position (incidence pupil position IP1) of the objective optical system is changed to the position shown in FIG. The front group 21 ″ ′ and the rear group sandwiching the intermediate imaging position P1 so that the pupil position (incidence pupil position IP1) of the objective lens and the entrance pupil position IP3 of the relay optical system 3 are substantially conjugate with each other according to the change. It can be exchanged for an imaging lens group 2 ″ ′ composed of 22 ″ ′.

  In the state shown in FIG. 10A, the front group 21 ″ of the imaging lens group 2 ″ includes, in order from the object side, a cemented lens of a biconvex lens L211 and a negative meniscus lens L212 having a concave surface facing the object side. A negative meniscus lens L213 ″ having a convex surface facing the object side and a cemented lens of a positive meniscus lens L214 ″ ″ having a convex surface facing the object side. The rear group 22 ″ has a concave surface facing the object side. And a positive meniscus lens L221 ′ ″.

  On the other hand, in the state shown in FIG. 10B, the front group 21 ′ ″ of the imaging lens group 2 ′ ″ includes, in order from the object side, a biconvex lens L211 and a negative meniscus lens L212 having a concave surface facing the object side. The cemented lens is composed of a cemented lens of a biconvex lens L213 ′ and a negative meniscus lens L214 ′ ″ with a concave surface facing the object side. The rear group 22 ′ ″ is also composed of a biconvex lens L221 in order from the object side. ”And a biconcave lens L222 ′, and a positive meniscus lens L223 ′ having a concave surface facing the object side.

  10A and 10B, the relay optical system 3 includes, in order from the object side, a negative meniscus lens L31 having a concave surface on the object side and a negative meniscus having a concave surface on the object side. A cemented lens with a meniscus lens L32 ″, a cemented lens with a negative meniscus lens L33 ′ having a convex surface facing the object side and a biconvex lens L34, a cemented lens with a biconvex lens L35 and a biconcave lens L36 ′, and a biconvex lens L37 ″ And a positive meniscus lens L38 having a convex surface facing the object side.

Next, numerical data of optical members constituting the microscopic optical system of Example 4 are shown.
Numerical data 4-1 (Example 4: State 1)
S ₁ (objective pupil position) r ₁ = ∞ d ₁ = 20.000
S ₂ (with objective lens barrel) r ₂ = ∞ d ₂ = 220.000
S ₃ (imaging lens front group) r ₃ = 102.633 d ₃ = 6.100 n _d3 = 1.48749 ν _d3 = 70.23
S ₄ r ₄ = -67.351 d ₄ = 4.000 n _d4 = 1.7185 ν _d4 = 33.52
S ₅ r ₅ = −168.369 d ₅ = 27.119
S ₆ r ₆ = 142.751 d ₆ = 9.009 n _d6 = 1.58267 ν _d6 = 46.42
S ₇ r ₇ = 70.046 d ₇ = 6.944 n _d7 = 1.618 ν _d7 = 63.33
S ₈ r ₈ = 1571.694 d ₈ = 81.450
S ₉ (intermediate image position) r ₉ = ∞ d ₉ = 76.769
S ₁₀ (back lens group) r ₁₀ = -30.624 d ₁₀ = 7.937 n _d10 = 1.78472 ν _d10 = 25.68
S ₁₁ r ₁₁ = -21.519 d ₁₁ = 4.248
S ₁₂ (pupil conjugate position) r ₁₂ = ∞ d ₁₂ = 4.347
S ₁₃ (Relay lens group) r ₁₃ = -9.402 d ₁₃ = 9.973 n _d13 = 1.7725 ν _d13 = 49.6
S ₁₄ r ₁₄ = -16.463 d ₁₄ = 6.676 n _d14 = 1.497 ν _d14 = 81.54
S ₁₅ r ₁₅ = -17.349 d ₁₅ = 1.556
S ₁₆ r ₁₆ = 270.157 d ₁₆ = 2.703 n _d16 = 1.741 ν _d16 = 52.64
S ₁₇ r ₁₇ = 24.096 d ₁₇ = 8.196 n _d17 = 1.43875 ν _d17 = 94.93
S ₁₈ r ₁₈ = -20.324 d ₁₈ = 0.300
S ₁₉ r ₁₉ = 54.582 d ₁₉ = 7.500 n _d19 = 1.43875 ν _d19 = 94.93
S ₂₀ r ₂₀ = -20.227 d ₂₀ = 2.000 n _d20 = 1.7725 ν _d20 = 49.6
S ₂₁ r ₂₁ = 55.591 d ₂₁ = 0.150
S ₂₂ r ₂₂ = 26.701 d ₂₂ = 6.516 n _d22 = 1.497 ν _d22 = 81.54
S ₂₃ r ₂₃ = -87.254 d ₂₃ = 0.463
S ₂₄ r ₂₄ = 28.755 d ₂₄ = 7.557 n _d24 = 1.618 ν _d24 = 63.33
S ₂₅ r ₂₅ = 100.475 d ₂₅ = 28.487
S ₂₄ (imaging surface) r ₂₄ = ∞

Numerical data 4-2 (Example 4: State 2)
S ₁ (objective pupil position) r ₁ = ∞ d ₁ = 20.000
S ₂ (with objective lens barrel) r ₂ = ∞ d ₂ = 120.000
S ₃ (imaging lens front group) r ₃ = 102.633 d ₃ = 6.100 n _d3 = 1.48749 ν _d3 = 70.23
S ₄ r ₄ = -67.351 d ₄ = 4.000 n _d4 = 1.7185 ν _d4 = 33.52
S ₅ r ₅ = −168.369 d ₅ = 58.365
S ₆ r ₆ = 80.897 d ₆ = 6.328 n _d6 = 1.48749 ν _d6 = 70.23
S ₇ r ₇ = -52.228 d ₇ = 3.500 n _d7 = 1.72916 ν _d7 = 54.68
S ₈ r ₈ = −109.117 d ₈ = 56.196
S ₉ (intermediate image position) r ₉ = ∞ d ₉ = 59.403
S ₁₀ (imaging lens rear group) r ₁₀ = 28.234 d ₁₀ = 3.599 n _d10 = 1.618 ν _d10 = 63.33
S ₁₁ r ₁₁ = -45.585 d ₁₁ = 4.372 n _d11 = 1.48749 ν _d11 = 70.23
S ₁₂ r ₁₂ = 24.912 d ₁₂ = 10.950
S ₁₃ r ₁₃ = -30.433 d ₁₃ = 8.591 n _d13 = 1.78472 ν _d13 = 25.68
S ₁₄ r ₁₄ = -22.987 d ₁₄ = 2.171
S ₁₅ (pupil conjugate position) r ₁₅ = ∞ d ₁₅ = 4.347
S ₁₆ (relay lens group) r ₁₆ = −9.402 d ₁₆ = 9.973 n _d16 = 1.7725 ν _d16 = 49.6
S ₁₇ r ₁₇ = -16.463 d ₁₇ = 6.676 n _d17 = 1.497 ν _d17 = 81.54
S ₁₈ r ₁₈ = -17.349 d ₁₈ = 1.556
S ₁₉ r ₁₉ = 270.157 d ₁₉ = 2.703 n _d19 = 1.741 ν _d19 = 52.64
S ₂₀ r ₂₀ = 24.096 d ₂₀ = 8.196 n _d20 = 1.43875 ν _d19 = 94.93
S ₂₁ r ₂₁ = -20.324 d ₂₁ = 0.300
S ₂₂ r ₂₂ = 54.582 d ₂₂ = 7.500 n _d22 = 1.43875 ν _d22 = 94.93
S ₂₃ r ₂₃ = -20.227 d ₂₃ = 2.000 n _d23 = 1.7725 ν _d23 = 49.6
S ₂₄ r ₂₄ = 55.591 d ₂₄ = 0.150
_{S 25 r 25 = 26.701 d 25} = 6.516 n d25 = 1.497 ν d25 = 81.54
S ₂₆ r ₂₆ = -87.254 d ₂₆ = 0.463
S ₂₇ r ₂₇ = 28.755 d ₂₇ = 7.557 n _d27 = 1.618 ν _d27 = 63.33
S ₂₈ r ₂₈ = 100.475 d ₂₈ = 28.487
S ₂₉ (imaging surface) r ₂₉ = ∞

Next, Table 1 shows the values corresponding to the conditional expression and the paraxial amount in each example.
Table 1

  The microscopic optical system of the present invention is useful in the field of taking microscopic observation images in various applications, particularly in the field where it is necessary to take microscopic observation images at a reduction magnification.

(a), (b) is a schematic block diagram along the optical axis of the microscope imaging optical system concerning 1st Embodiment of this invention. (a)-(c) is a schematic block diagram along the optical axis of the conventional microscope imaging optical system concerning the comparative example of this invention. (a)-(c) is a schematic block diagram along the optical axis of the microscope optical system concerning 2nd Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing in alignment with the optical axis which shows schematic structure about the principal part of the microscope imaging optical system concerning Example 1 of this invention, Comprising: (a) is a state corresponding to FIG. (B) shows a state corresponding to FIG. 1 (b) (hereinafter referred to as state 2). FIG. 5 is a graph showing spherical aberration, field curvature, distortion, and coma aberration of the microscopic optical system of FIG. 4, where (a) shows aberrations in state 1 and (b) shows aberrations in state 2, respectively. ing. It is sectional drawing in alignment with the optical axis which shows schematic structure about the principal part of the microscope imaging optical system concerning Example 2 of this invention, Comprising: (a) is the state (state 1) corresponding to FIG. b) shows a state (state 2) corresponding to FIG. 1 (b). FIG. 7 is a graph showing the spherical aberration, field curvature, distortion, and coma aberration of the microscopic optical system of FIG. 6, where (a) shows the aberration in state 1 and (b) shows the aberration in state 2. Respectively. It is sectional drawing in alignment with the optical axis which shows schematic structure about the principal part of the microscope imaging optical system concerning Example 3 of this invention, Comprising: (a) is the state (state 1) corresponding to FIG. b) shows a state (state 2) corresponding to FIG. 1 (b). FIG. 9 is a graph showing spherical aberration, field curvature, distortion aberration, and coma aberration of the microscope photographing optical system in FIG. 8, where (a) shows aberration in state 1 and (b) shows aberration in state 2, respectively. ing. It is sectional drawing in alignment with the optical axis which shows schematic structure about the principal part of the microscope imaging optical system concerning Example 4 of this invention, Comprising: (a) is the state (state 1) corresponding to FIG. b) shows a state (state 2) corresponding to FIG. 1 (b). FIG. 11 is a graph showing spherical aberration, curvature of field, distortion, and coma aberration of the microscopic optical system of FIG. 10, where (a) shows aberrations in state 1 and (b) shows aberrations in state 2, respectively. ing.

Explanation of symbols

1 Infinity Correction Objective Lens 2, 2 ', 2 ", 2"' Imaging Lens Group 21, 21 ', 21 ", 21"' Front Group 22, 22 ', 22 ", 22"' Rear Group 3 Relay Lens 4 Image sensor L211 Biconvex lens L212 Negative meniscus lens L213 with concave surface facing the object side Positive meniscus lens L213 ′ with convex surface facing the object side Biconvex lens L213 ”Negative meniscus lens L214 with convex surface facing the object side Convex surface on the object side Negative meniscus lens L214 'with a concave surface facing the object side Bimenular lens L214'"negative meniscus lens L214" with a concave surface facing the object side positive meniscus lens L221 with a convex surface facing the object side A positive meniscus lens L221 ′ having a convex surface facing the side. A planoconvex lens L221 ″ having a convex surface on the object side and a flat surface on the image side. Positive meniscus lens L222 having a concave surface facing the body side Plano-concave lens L222 ′ having a flat object side and a concave surface on the image side Bi-concave lens L223 Positive meniscus lens L223 ′ having a convex surface facing the object side Positive meniscus lens L31 having a concave surface facing the object side A negative meniscus lens L31 ′ having a concave surface facing the object and a plano-concave lens L32 ′ having a concave surface on the object side and a flat surface on the image side. Negative meniscus lens L33 Bi-concave lens L33 ′ Negative meniscus lens L34 with convex surface facing the object side Biconvex lens L35 Biconvex lens L36 Negative meniscus lens L36 ′ with concave surface facing the object side Bi-concave lens L37 Negative with convex surface facing the object side Meniscus lens L37 ′ Positive meniscus lens L with a convex surface facing the object side 7 "Biconvex lens L38 Positive meniscus lens with convex surface facing the object side IP1 Entrance pupil position OP1 of objective lens Exit pupil position IP3 of objective lens Entrance pupil position IM of relay lens Imaging plane P1 Intermediate imaging position P2 Entrance pupil of objective lens Position S conjugate with position IP3 Brightness stop

Claims (8)

In order from the object side, an infinity correction objective lens, an imaging lens group that forms an intermediate image from the light beam from the objective lens, and a relay optical system for imaging the light beam from the imaging lens group ,
The imaging lens group has a front group and a rear group across an intermediate image position, and the entrance pupil position of the objective lens and the entrance pupil position of the relay optical system according to a change in the pupil position of the objective lens A microscope optical system characterized in that it is configured to be interchangeable as an imaging lens group having different configuration conditions so that and are substantially conjugated. The imaging lens group constitutes the imaging lens group such that when the pupil position of the objective lens changes, the entrance pupil position of the objective lens and the entrance pupil of the relay optical system are substantially conjugate. The microscope photographing optical system according to claim 1, wherein the combination of lenses to be changed is configured to be changeable. The imaging lens group constitutes the imaging lens group such that when the pupil position of the objective lens changes, the entrance pupil position of the objective lens and the entrance pupil of the relay optical system are substantially conjugate. The microscope photographing optical system according to claim 1, wherein an interval between predetermined lenses is changed. The microscope imaging optical system according to any one of claims 1 to 3, wherein the imaging lens group includes an afocal optical system. The imaging lens group moves at least one lens group constituting the afocal optical system in the optical axis direction so that the entrance pupil position of the objective lens and the entrance pupil position of the relay optical system are substantially conjugate. The microscope photographing optical system according to claim 4, wherein the microscope photographing optical system is configured as follows. The microscope imaging optical system according to claim 1, wherein the imaging lens group is further configured to have a zooming action. The relay optical system includes a plurality of lens groups, and an entrance pupil position of the relay optical system is disposed between the imaging lens group and the relay optical system. A microscope photographing optical system according to the above. The focal length of the relay optical system is F1, the focal length of the entire system is F, the amount of fluctuation of the pupil position of the objective lens is ΔD, the distance from the most image side surface to the final image plane in the relay optical system is d, 8. The microscopic optical system according to claim 1, wherein the following conditional expressions (1) to (3) are satisfied when the total length from the image lens group to the final image plane is L0. .
0.2 ≦ ΔD / L0 ≦ 0.4 (1)
0.4 ≦ | F1 / F | ≦ 0.9 (2)
0.5 ≦ F1 / d ≦ 0.8 (3)