JP2001100093A - Relay optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relay optical system constituted so that an image pickup device can be mounted on a microscope without causing any structural interference between the microscope and image pickup device. SOLUTION: This system is composed of a 1st group G1 with negative refracting power and 2nd group G2 with positive refracting power which are arranged in order from an intermediate imaging position I to an projection side and the distance from the final lens surface r8 of the 2nd group G2 to an exit pupil position EXP is set to 30 to 90 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay optical system used for picking up an image formed by an objective lens with an electronic camera or the like.

[0002]

2. Description of the Related Art As means for recording an image formed by an objective lens of a microscope, there is a method using a silver halide camera and a method using a television camera. Of these, when photographed with a silver halide camera, the specimen image was recorded on film.

On the other hand, an imaging method using a television camera is disclosed in Japanese Patent Application Laid-Open No. Hei 6-331903. In this case, an eyepiece observation lens barrel, an adapter, an attachment for a television camera, and a television camera connection mirror comprising an imaging section of the television camera. A tube is shown. Although the image sensor is not specifically described, for example, a solid-state image sensor (CCD) is used.

Conventionally, the number of pixels of a solid-state imaging device is roughly determined according to the number of scanning lines of a television monitor. For example, in the case of a standard system (NTSC), for example, 512 × 512
Pixels or 640 × 512 pixels, for example, 1024 × 768 pixels for high definition.

[0005]

As described above, in conventional photography, a sample image is recorded on a film, but in recent years, a solid-state image sensor has been used instead of a film as a recording medium. Digital cameras have appeared and started to spread. The feature of this digital camera is that the number of pixels is large compared to the area of the solid-state imaging device.
100-2 in inch size or 1/2 inch size
It has more than one million pixels or more.

However, in a digital camera, a photographing lens is fixed to a camera body, and an entrance pupil position exists in the photographing lens or in the digital camera body. Therefore, when attempting to use the microscope in combination with a microscope to capture a specimen image, the digital camera body must be moved to the microscope in order to match the exit pupil position of the microscope (or a position conjugate to the exit pupil position) with the entrance pupil position of the digital camera. It must be located close to the lens barrel. As a result, there arises a problem that the microscope and the digital camera cause structural interference. It should be noted that Japanese Patent Application Laid-Open Nos.
JP-A-54258, JP-A-9-133875 and JP-A-10-39235 disclose an optical system for observing an image (intermediate image) formed by an objective lens. It is difficult to use as a relay optical system for an imaging device because it is assumed that the image is observed with the eyes of the subject.

SUMMARY OF THE INVENTION An object of the present invention is to provide a relay optical system which allows a microscope to be mounted on an image pickup apparatus without causing structural interference between the microscope and the image pickup apparatus when a sample image is taken by the image pickup apparatus. Is to do.

[0008]

A relay optical system according to the present invention comprises a first group having a negative refractive power and a second group having a positive refractive power, which are arranged in order from the intermediate image forming position to the exit side. Wherein the distance from the last lens surface of the second group to the exit pupil position is 30 mm to 90 mm. The relay optical system according to the present invention is characterized in that the first group includes a cemented lens, and the second group includes two positive lenses. Further, the relay optical system according to the present invention is characterized in that the first group includes a negative meniscus lens having a convex surface facing the intermediate image forming position side, and the second group includes a cemented lens and a positive lens. Further, the relay optical system according to the present invention is characterized in that the first group includes a biconcave lens, and the second group includes a cemented lens and a positive lens. The relay optical system according to the present invention is characterized by satisfying the following condition (1). 0.3 ≦ L / f ≦ 1.25 (1) where L is the total length of the relay optical system, and is the distance from the lens surface on which light is first incident to the lens surface on which light is emitted last, and f is the focal point Distance. Further, the relay optical system according to the present invention is characterized by satisfying the following conditions (2) to (4). −12 ≦ f1 / f ≦ −0.5 (2) 0.45 ≦ f2 / f ≦ 1.5 (3) 0.9 ≦ d _EXP /f≦1.5 (4) where f is the relay optical The focal length of the system, f1 is the focal length of the first group, f2 is the focal length of the second group, d
_EXP is the distance from the last lens surface of the second group to the exit pupil position.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below with reference to the illustrated embodiments. Each embodiment includes a first group having a negative refractive power and a second group having a positive refractive power, which are arranged on the emission side in order from the intermediate imaging position. In the first configuration, the first group having a negative refractive power is composed of a cemented lens, and the second group having a positive refractive power is 2
Consists of a single positive lens. In the second configuration, the first group having a negative refractive power includes a negative meniscus lens having a convex surface facing the intermediate imaging position, and the second group having a positive refractive power includes a cemented lens and a positive lens. Become. In the third configuration, the first group having a negative refractive power includes a biconcave lens,
The second group having a positive refractive power includes a cemented lens and a positive lens. Here, it is desirable that the first to third configurations satisfy the following condition (1). 0.3 ≦ L / f ≦ 1.25 (1) where L is the total length of the relay optical system, and is the distance from the lens surface on which light is first incident to the lens surface on which light is emitted last, and f is the focal point Distance.

In the condition (1), when the value of L / f is smaller than the lower limit of 0.3, the number of lenses is reduced, and it is difficult to satisfactorily correct the aberration of the relay optical system. Further, when the value exceeds the upper limit value of 1.25, it is difficult to secure a necessary distance to the exit pupil position. Therefore, it is more desirable to satisfy the following condition (1 ′). 0.40 ≦ L / f ≦ 1.25 (1 ′) In the first to third configurations, it is preferable that the following conditions (2) to (4) are satisfied. −12 ≦ f1 / f ≦ −0.5 (2) 0.45 ≦ f2 / f ≦ 1.5 (3) 0.9 ≦ d _EXP /f≦1.5 (4) where f is the relay optical Focal length of the system, f1 is the focal length of the first group, f2 is the focal length of the second group, d _EXP
Is the distance from the last lens surface of the second group to the exit pupil position.

In the condition (2), if the value of f1 / f becomes smaller than the lower limit of −12, the refractive power of the first lens unit becomes weak, the Petzval sum cannot be reduced, and the field curvature cannot be sufficiently reduced. Cannot be corrected. If the value exceeds the upper limit of -0.5, the refractive power of the first lens unit increases, making it difficult to satisfactorily correct the aberration of the entire relay optical system. Becomes large.

In condition (3), when the value of f2 / f is smaller than the lower limit of 0.45, the refractive power of the second lens unit increases, and accordingly, the refractive power of the first lens unit also increases. In this case, since the amount of aberration generated in each of the first and second units increases, spherical aberration and curvature of field cannot be canceled out in the first and second units, and it becomes difficult to perform well-balanced aberration correction. . Also, if the value exceeds the upper limit of 1.5, the second
The refractive power of the group becomes weaker, and accordingly, the refractive power of the first group becomes weaker. As a result, the negative refractive power is insufficient, and it becomes difficult to effectively correct the field curvature.

In the condition (4), if the value of d _EXP / f becomes smaller than the lower limit of 0.9 or becomes larger than the upper limit of 1.5, the d _EXP / f may be used in combination with a microscope. In addition, it is difficult to dispose the imaging device at an appropriate position with good balance. Note that d _EXP is a value when the entrance pupil position of the relay optical system is at approximately infinity.

FIG. 1 shows a microscope using the relay optical system of the present invention. In the figure, 1 is a microscope main body, 2 is an observation lens barrel, 3 is a relay optical system, 4 is a first holding member for holding the relay optical system 3, 5 is a second holding member, and 6 is a digital camera (electronic camera). Imaging camera). Reference numeral 11 denotes a revolver, 12 denotes an objective lens, and 13 denotes a stage on which the sample S is mounted.

The observation lens barrel 2 has its lower part installed on the upper surface of the lens body 1, and an observation optical path 2 A for observing an image of the sample S with the eye and an image pickup lens for photographing with the digital camera 6. Has an imaging optical path 2B. An eyepiece 9 is arranged on the observation optical path 2A of the observation lens barrel 2, so that observation by the observer's eyes is possible. Observation optical path 2A and photographing optical path 2B
Is switched by operating a switching lever (not shown) and inserting and removing the prism 10 in and out of the optical path. Also, I is an intermediate image of the specimen, which is formed outside the observation lens barrel 2.

A first holding member 4 is provided on the upper part of the observation lens barrel 2, and the first holding member 4 is connected to the observation lens barrel 2 via its lower end 4A. The first holding member 4 has a cylindrical shape, and the relay optical system 3 is disposed inside the first holding member 4.

The relay optical system 3 is disposed near the upper end 4B of the first holding member 4 so that the sample image I is focused on its front focal position,
Alternatively, it is held inside the first holding member 4 so as to coincide with the vicinity thereof. Accordingly, light from each point of the sample image I is converted into a parallel light beam or a substantially parallel light beam by the relay optical system 3 and enters the digital camera 6. Further, the exit pupil of the microscope (or a conjugate point thereof) and the entrance pupil of the digital camera 6 coincide with each other by the relay optical system 3.

A second holding member 5 is provided above the first holding member 4.
Is installed, and the upper end 4B of the first holding member 4 and the lower end 5A of the second holding member 5 are connected. The second holding member 5 is
It has a cylindrical shape like the holding member 4 of 1, but has no lens inside and is hollow.

A digital camera is provided above the second holding member 5.
6 is connected. Shooting lens 6A of digital camera 6
An adapter 7 for connecting to the second holding member 5 is provided on an outer peripheral portion of the second holding member 5.
Is connected to the upper end 5B. Note that the digital camera 6 may be directly connected to the second holding member 5 if structurally possible.

The connection of each member such as the connection between the main body 1 and the observation lens barrel 2 and the connection between the second holding member 5 and the adapter 7 is conventionally used such as a screw mechanism or a round dovetail mechanism. A mechanism is appropriately selected and used.

The relay optical system 3 satisfies the following condition (5)
Are satisfied. 30 mm ≦ D ≦ 90 mm (5) Here, D is the distance from the lens surface of the relay optical system 3 closest to the digital camera 6 to the entrance pupil position 8 of the digital camera 6.

When the distance D is smaller than the lower limit of 30 mm, the distance between the observation lens barrel 2 and the digital camera 6 becomes short, and a structural stroll occurs. In addition, when a digital camera having a photographing lens with a long focal length is connected, the entrance pupil of such a digital camera is located near the image pickup device, so that there is a problem that light rays of a peripheral image are shaded. .

On the other hand, when the distance D exceeds the upper limit of 90 mm, the distance from the observation lens barrel 2 to the digital camera 6 is too large, so that the stability is deteriorated and a sharp sample image cannot be photographed. In addition, it is difficult to increase the magnification of the relay optical system 3, and it is not possible to take an image up to the angle of view that the photographing lens 6A of the digital camera 6 originally has without being blurred. Occurs.

Since the relay optical system 3 according to the present invention satisfies the above condition (5), the digital camera 6 and the observation lens barrel 2 can be separated without deteriorating the stability. Therefore, it is possible to capture a stable sample image without causing structural interference. Further, since the optical system optically matches the optical characteristics of the photographing lens 6A of the digital camera, it is possible to obtain a good sample image without shading over the entire photographing range.

The relay optical system 3 satisfies the following condition (6):
Is preferably satisfied. 60mm ≦ D ≦ 80mm (6)

Embodiment 1 FIG. 2 shows a first embodiment of the relay optical system 3 according to the present invention. This embodiment is a relay optical system having a first configuration, in which a first group G1 having a negative refractive power is arranged in the order of a biconcave lens and a biconvex lens from the intermediate image position side to the exit pupil position EXP side. A second group G2 composed of a lens and having a positive refractive power
Consists of two biconvex lenses. The first with negative refractive power
The biconcave lens and the biconvex lens of the group G1 are all lenses having the same radius of curvature. Further, the two biconvex lenses of the second group G2 having a positive refractive power have different shapes from each other, but are arranged such that surfaces having a small radius of curvature face each other.

Hereinafter, numerical data of this embodiment will be shown. Here, R represents the radius of curvature of each lens surface, T represents the thickness or air space of each lens, nd represents the refractive index of each lens in the d-line, and νd represents the Abbe number of each lens. ,
These are commonly used in each embodiment described later. However, the INF on the first surface indicates the intermediate imaging position, and the INF on the ninth surface
Indicates the exit pupil position EXP. FIG. 3 is an aberration curve diagram showing spherical aberration, astigmatism, and distortion in the present embodiment.

Surface number (r) R T nd νd 1 INF 11.1142 2 -30.393 4.2000 1.84666 23.78 3 30.393 10.9000 1.58913 61.14 4 -30.393 1.0000 5 145.200 6.1000 1.48749 70.23 6 -45.256 1.0000 7 34.698 8.4000 1.48749 70.23 8 -87.355 35.9300 9 INF

Embodiment 2 FIG. 4 shows a second embodiment of the relay optical system according to the present invention. In the present embodiment, similarly to the first embodiment, the first negative refractive power
The group G1 is composed of a cemented lens arranged in the order of a biconcave lens and a biconvex lens from the intermediate image position side, and the second group G2 having a positive refractive power is composed of two biconvex lenses. The biconcave lens of the first group G1 having a negative refractive power has the same radius of curvature on both surfaces. The two biconvex lenses of the second group G2 having a positive refractive power are lenses having the same shape, and are arranged such that surfaces having a small radius of curvature face each other. Hereinafter, numerical data of the present embodiment will be shown. Each aberration curve of the present embodiment is substantially the same as each aberration curve of the first embodiment, and can be calculated from the data by ray tracing, and is not shown.

Surface number (r) R T nd νd 1 INF 7.1015 2 -19.467 3.0000 1.84666 23.78 3 19.467 11.4000 1.58913 61.14 4 -24.763 1.0000 5 68.589 6.0000 1.48749 70.23 6 -36.368 1.0000 7 36.368 6.0000 1.48749 70.23 8 -68.589 35.5870 9 INF

Embodiment 3 FIG. 5 shows a third embodiment of the relay optical system according to the present invention. In the present embodiment, similarly to the first embodiment, the first negative refractive power
The group G1 is composed of a cemented lens arranged in the order of a biconcave lens and a biconvex lens from the intermediate image position side, and the second group G2 having a positive refractive power is composed of two biconvex lenses. The biconvex lenses of the first group G1 having a negative refractive power have the same radius of curvature on both surfaces. Further, the two biconvex lenses of the second group G2 having a positive refractive power have different shapes from each other, but are arranged such that surfaces having a small radius of curvature face each other. Hereinafter, numerical data of the present embodiment will be shown. Each aberration curve of the present embodiment is the same as that of the first embodiment.
Are substantially the same as those of the respective aberration curves and can be calculated by ray tracing from the data, and are not shown.

Surface number (r) R T nd νd 1 INF 12.2390 2 -45.876 5.1000 1.84666 23.78 3 32.066 11.0000 1.58913 61.14 4 -32.066 1.0000 5 97.713 5.9000 1.48749 70.23 6 -71.183 1.0000 7 29.992 9.2000 1.48749 70.23 8 -168.989 31.0529 9 INF

Embodiment 4 FIG. 6 shows a relay optical system according to a fourth embodiment of the present invention. This embodiment is a relay optical system having a second configuration,
The first group G1 having a negative refractive power includes a negative meniscus lens having a convex surface facing the intermediate image position side, and the second group G2 having a positive refractive power.
Denotes a relay optical system including a cemented lens arranged in the order of a positive lens and a negative lens from the intermediate image position side, and one positive lens. The cemented lens of the second group G2 having a positive refractive power includes a biconvex lens and a negative meniscus lens having a concave surface facing the intermediate image position side, and has a positive refractive power as a whole. Also,
The positive lens of the second group G2 having a positive refractive power is a biconvex lens. Hereinafter, numerical data of the present embodiment will be shown. FIG. 7 is an aberration curve diagram showing spherical aberration, astigmatism, and distortion in the present example.

Surface number (r) R T nd νd 1 INF 11.8417 2 32.1231 4.0000 1.69895 30.13 3 20.1111 3.0925 4 55.7176 10.6575 1.51633 64.14 5 -16.7356 3.8973 1.74077 27.79 6 -43.3920 1.0000 7 55.3289 9.0162 1.69100 54.82 8 -39.7557 30.1409 9 INF

Embodiment 5 FIG. 8 shows a fifth embodiment of the relay optical system according to the present invention. In the present embodiment, as in the case of the fourth embodiment, the first refractive power having the negative refractive power
A group G1 is composed of a meniscus lens having a negative refractive power with the convex surface facing the intermediate image position side, and a second group G2 having a positive refractive power is a cemented lens arranged in the order of a biconvex lens and a biconcave lens from the intermediate image position side. 1 is a relay optical system including one positive lens. The cemented lens of the second group G2 having a positive refractive power includes a biconvex lens and a negative meniscus lens having a concave surface facing the intermediate image position side, and has a positive refractive power as a whole. The positive lens of the second group G2 having a positive refractive power is a positive meniscus lens having a concave surface facing the intermediate image position side. Hereinafter, numerical data of the present embodiment will be shown. Each aberration curve of the present embodiment is substantially the same as each aberration curve of the fourth embodiment, and can be calculated by ray tracing from data, and is not shown.

Surface number (r) R T nd νd 1 INF 35.5987 2 89.0738 4.0000 1.69895 30.13 3 27.0854 5.2995 4 38.2208 11.0000 1.51633 64.14 5 -27.3767 4.0000 1.74077 27.79 6 -35.9861 1.8190 7 -110.2847 6.0000 1.69100 54.82 8 -61.0450 65.6

Embodiment 6 FIG. 9 shows a relay optical system according to a sixth embodiment of the present invention. This embodiment is a relay optical system having a third configuration,
The first group G1 having a negative refractive power includes a biconcave lens, and the second group G2 having a positive refractive power includes a cemented lens arranged in the order of a positive lens and a negative lens from the intermediate image position side, and a single positive lens. This is a relay optical system. The cemented lens of the second group G2 having a positive refractive power includes a biconvex lens and a negative meniscus lens having a concave surface facing the intermediate image position side, and has a positive refractive power as a whole. The positive lens of the second group G2 having a positive refractive power is a biconvex lens. Hereinafter, numerical data of the present embodiment will be shown. FIG. 10 is an aberration curve diagram showing spherical aberration, astigmatism, and distortion in the present example.

Surface number (r) R T nd νd 1 INF 14.6795 2 -417.2840 3.5000 1.68893 31.07 3 34.6376 3.6016 4 47.5064 10.9500 1.49700 81.54 5 -18.3517 3.8598 1.74077 27.79 6 -29.4224 0.5000 7 47.2898 6.4300 1.74100 52.64 8 9 -157.4495 3181

Embodiment 7 FIG. 11 shows a relay optical system according to a seventh embodiment of the present invention. In the present embodiment, similarly to the sixth embodiment, the first unit G1 having a negative refractive power includes a biconcave lens, and the second unit G having a positive refractive power.
Reference numeral 2 denotes a relay optical system including a cemented lens arranged in the order of a positive lens and a negative lens from the intermediate image position side, and one positive lens. The cemented lens of the second group G2 having a positive refractive power includes a biconvex lens and a negative meniscus lens having a concave surface facing the intermediate image position side, and has a positive refractive power as a whole. The positive lens of the second group G2 having a positive refractive power is a positive meniscus lens having a convex surface facing the intermediate image position side. Hereinafter, numerical data of the present embodiment will be shown. Each aberration curve of this embodiment is
The aberration curves are almost the same as those of the sixth embodiment, and can be calculated from the data by ray tracing.

Surface number (r) RT nd νd 1 INF 41.1156 2 -89.8328 7.5000 1.68893 31.07 3 41.3356 3.7277 4 56.6411 11.0304 1.49700 81.54 5 -31.3968 4.6442 1.74077 27.79 6 -33.6487 0.5000 7 59.6636 5.9477 1.74100 52.64 8 146.6294 88.0016 9 INF

Hereinafter, the values of the conditional expressions in the above embodiments are collectively displayed. IM.H is the size of the intermediate image, and NA is the numerical aperture on the incident side (intermediate image side).

[0042]

As described above, according to the present invention, when a specimen image is taken by an imaging device, the imaging device can be mounted on the microscope without causing structural interference between the microscope and the imaging device. A relay optical system can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a microscope using a relay optical system of the present invention.

FIG. 2 is a sectional view taken along the optical axis of the first embodiment of the relay optical system according to the present invention.

FIG. 3 is an aberration diagram in the first example.

FIG. 4 is a sectional view taken along the optical axis of a second embodiment of the relay optical system according to the present invention.

FIG. 5 is a sectional view taken along the optical axis of a third embodiment of the relay optical system according to the present invention.

FIG. 6 is a sectional view taken along the optical axis of a fourth embodiment of the relay optical system according to the present invention.

FIG. 7 is an aberration diagram in the fourth embodiment.

FIG. 8 is a sectional view taken along the optical axis of a fifth embodiment of the relay optical system according to the present invention.

FIG. 9 is a sectional view taken along the optical axis of a sixth embodiment of the relay optical system according to the present invention.

FIG. 10 is an aberration diagram in the sixth example.

FIG. 11 is a sectional view taken along the optical axis of a seventh embodiment of the relay optical system according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Microscope main body 2 Observation lens barrel 3 Relay optical system 4 First holding member 5 Second holding member 6 Electronic imaging camera (digital camera) 7 Adapter 8 Entrance pupil position 9 Eyepiece 10 Prism 11 Revolver 12 Objective lens 13 Stage S sample I Intermediate image of sample

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H052 AB24 AD33 AF14 2H087 KA09 LA27 NA02 PA03 PA18 PB04 QA02 QA03 QA06 QA07 QA12 QA14 QA21 QA22 QA25 QA37 QA39 QA41 QA45 QA46

Claims (6)

[Claims] A first lens unit having a negative refractive power and a second lens unit having a positive refractive power, arranged in order from an intermediate image forming position to an exit side; A relay optical system in which the distance from the surface to the exit pupil position is 30 mm to 90 mm. 2. The relay optical system according to claim 1, wherein said first group comprises a cemented lens, and said second group comprises two positive lenses. 3. The relay optical system according to claim 1, wherein the first group comprises a negative meniscus lens having a convex surface facing the intermediate image forming position, and the second group comprises a cemented lens and a positive lens. 4. The relay optical system according to claim 1, wherein said first group comprises a biconcave lens, and said second group comprises a cemented lens and a positive lens. 5. The relay optical system according to claim 1, wherein the following condition (1) is satisfied. 0.3 ≦ L / f ≦ 1.25 (1) where L is the total length of the relay optical system, and is the distance from the lens surface on which light is first incident to the lens surface on which light is emitted last, and f is the focal point Distance. 6. The relay optical system according to claim 1, wherein the following conditions (2) to (4) are satisfied. −12 ≦ f1 / f ≦ −0.5 (2) 0.45 ≦ f2 / f ≦ 1.5 (3) 0.9 ≦ d _EXP /f≦1.5 (4) where f is the relay optical The focal length of the system, f1 is the focal length of the first group, f2 is the focal length of the second group, d
_EXP is the distance from the last lens surface of the second group to the exit pupil position.