JP2003172881A - Imaging camera connection adapter for microscope - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make a contribution to acquiring of high-quality observation images by decreasing spot flare phenomena. <P>SOLUTION: The imaging camera connection adapter is formed by housing and arranging a beam attenuating lens 33 interposed between a splitting prism 17 of a lens barrel 15 and an imaging element 21 of a TV camera to an adapter body 30 at a prescribed angle of inclination with an imaging optical axis X' in such a manner that the reflected light reflected by the surface of the imaging element 21 is effectively attenuated by this beam attenuating filter 33. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a microscope, and more particularly to an image pickup camera connection adapter used for connecting and arranging an image pickup camera such as a television camera for picking up an optical image captured by an objective lens thereof.

[0002]

2. Description of the Related Art Generally, a microscope image pickup camera connection adapter of this type is installed in a microscope body 10 as shown in FIG.
The stage 12 on which the specimen 11 is placed, the lamp house 1
3, the revolver 14, the lens barrel 15 and the like are assembled. The revolver 14 has an objective lens 16 on the stage 1
1. The split prism 17 housed in the lens barrel 15 is mounted on the observation optical axis of the objective lens 16 so as to be opposed thereto.
Is provided. An eyepiece lens 18 is disposed on one observation optical axis X of the split prism 17, and an image of the sample 11 captured by the objective lens 16 is guided through the eyepiece lens 18 through the split prism 17. Observer 1
Observed by 9.

An adapter body 1 for connecting an image pickup camera is detachably mounted on the other image pickup optical axis X'of the split prism 17. A projection lens 2 is built in the adapter body 1, and a television (TV) camera 20 is assembled so as to face the projection lens 2.

In the above structure, when observing the sample 11, the lamp house 13 is turned on with the sample 11 placed on the stage 12. Then, the illumination light emitted from the lamp house 13 illuminates the sample 11 on the stage 12, and the sample image is guided to the split prism 17 through the objective lens 16 to form the observation optical axis X and the imaging optical axis X ′. It is divided and guided to the eyepiece lens 18 and the projection lens 2 of the adapter body 1. The image guided to the eyepiece lens 18 is directly observed by the observer 19.

On the other hand, the image guided to the projection lens 2 is projected on the image pickup device 21 of the TV camera 20 by the projection lens 2, displayed on a monitor (not shown), and observed through a monitor (not shown). To be done.

However, in the microscope camera connection adapter, when observing a sample 11 having a high reflectance such as a flat surface of a semiconductor or a polished metal body, the amount of light reflected from the sample 11 is large. Moreover, since the directivity is strong, the reflected light reflected by the surface of the image pickup device 21 of the TV camera 20 (or the cover glass generally arranged on the surface of the image pickup device for dustproof) is reflected by the surface of the split prism 17. There is a problem that the so-called spot flare phenomenon occurs in which the center of the returning light is emphasized brightly again by returning to the image pickup device 21. If the spot flare occurs on the observed image due to the spot flare phenomenon, there is a possibility that erroneous observation may be caused when inspecting a semiconductor or observing a sample having a high reflectance.

[0007] Particularly, in recent microscope systems, the observation method of picking up and observing the sample 11 with an image pickup camera such as a TV camera 20 or a digital camera is often adopted, and the number of pixels of the image pickup element 21 is increased. There is a strong demand for promotion of high sensitivity, which is one of the important issues for the future.

[0008]

As described above, in the conventional microscope, when the image of the sample is acquired by using the imaging camera, in the case of the sample having high reflectance, the spot flare phenomenon causes an erroneous observation in the image observation. May lead to

The present invention has been made in view of the above circumstances, and is connected to a microscope image pickup camera having a simple structure to reduce the spot flare phenomenon and contribute to acquisition of a high-quality observation image. The purpose is to provide an adapter.

[0010]

According to the present invention, there is provided a first connecting portion for connecting to an optical device, a second connecting portion for connecting to an image pickup camera, and an optical image of the optical device projected on the image pickup camera. In a microscope image pickup camera connection adapter having a projection optical system, an optical element is arranged on the image pickup optical axis between the optical device and the image pickup camera with a predetermined inclination angle with respect to the image pickup optical axis. It is configured as follows.

According to the above arrangement, when the image captured by the optical device is guided, the optical element dims the light of the image and projects it on the image pickup element of the image pickup camera through the projection optical system. , Observation image data is acquired. This observation image data is automatically light-adjusted by, for example, an automatic gain control function and displayed on a monitor.

At this time, of the light reflected on the sample, the reflected light reflected on the surface of the image pickup element is again guided to the optical element, dimmed, and then guided to the optical device, and then the surface of the optical device. It is reflected by, and is again guided through the optical element to the image pickup element via the projection optical system. As a result, it is possible to prevent the spot flare phenomenon due to the reflected light on the surface of the image pickup device, easily realize a highly accurate observation image with the image pickup camera, and improve the observation precision. Here, the reflection of the reflected light on the surface of the optical element does not affect the observed image because it is arranged so as to be inclined with respect to the observation optical axis.

Further, according to the present invention, any one of a plurality of optical element portions having different spectral transmittances and an aperture portion arranged at a predetermined interval on the image pickup optical axis between the optical device and the image pickup camera is selected. It is configured with an element switching mechanism that can be arranged physically.

According to the above construction, by switching and setting the aperture of the optical element or a plurality of optical element sections, it becomes possible to cope with an image pickup camera having a desired performance and to diversify the usage form. Is possible.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows a microscope image pickup camera connection adapter according to an embodiment of the present invention. The adapter body 30 is, for example, the image pickup optical axis X of the split prism 17 of the lens barrel 15 shown in FIG. ′ Is detachably mounted on top.
Therefore, in the description of the adapter body 30 which is the feature of the present invention shown in FIG. 1, the same parts as those shown in FIG. 8 are designated by the same reference numerals, and the detailed description thereof will be omitted.

That is, an optical path 31 is formed in the adapter body 30 which is a feature of the present invention, corresponding to the image pickup optical axis X'of the split prism 17. Then, the adapter body 31
On the incident side of the optical path 31, a dovetail 32 is formed corresponding to a dovetail groove (not shown) provided on the lens barrel 15, and the dovetail 32 is used to attach the lens barrel 15 to the lens barrel 15. Detachable.

Further, in the optical path 31 of the adapter body 30,
A step portion 311 for mounting a filter is formed at an intermediate portion thereof with a predetermined inclination angle with respect to the image pickup optical axis X ′, and a neutral density filter 33 such as an ND filter is attached to this step portion 311 by a pressing ring 34. Is attached with a predetermined inclination with respect to the image pickup optical axis X '. Then, in the optical path 31 of the adapter body 30, the lens mounting portion 3 is provided at a stage subsequent to the step 311.
12 is formed, and the projection lens 35 is attached to the lens attachment portion 312 by using the pressing ring 36.

On the other side of the adapter body 30, a concave guide portion 37 for adjusting the focus is formed, and an adjusting screw portion 371 is formed at the tip of this guide portion. The adjusting screw portion 371 has a mount member 38 called a C mount.
The screw portion 381 of the above is screwed so as to be freely screwed and adjusted. This screwing adjustment range corresponds to the parfocal adjustment range L.

A camera mounting portion 382 is formed at the tip of the mount member 38, and the camera mounting portion 38 is formed.
The TV camera 20 is attached / detached to / from 2.

Further, a screw hole 39 for mount positioning is formed in the adapter body 30 so as to be orthogonal to the image pickup optical axis X ', and a clamp screw 40 is screwed into the screw hole 39. The clamp screw 39 has a concave portion (not shown for convenience of illustration) whose tip is formed on the outer periphery of the mount member 38.
When the mount member 38 is pressed against, the positioning of the mount member 38 in the direction of the image pickup optical axis X'is executed.

In the above structure, the adapter body 30 is
The dovetail 32 is fitted into a dovetail groove (not shown) of the lens barrel 15 to be attached to the lens barrel 15, and a mount member 38 is provided.
The not-shown attached portion of the TV camera 20 is attached to the camera attachment portion 382 of FIG. At this time, the clamp screw 3
9 is loosened, and the screw portion 381 of the mount member 38 is
And the adjustment screw portion 371 of the adapter body 30 is adjusted to adjust the focus of the TV camera 20. When the adjustment is completed, the clamp screw 40 is screwed in and the outer periphery of the mount member 38 is tipped. The parts are pressed against the above-mentioned recesses (not shown) to perform mutual positioning.

In this state, the lamp house 13 is turned on, the sample 11 is illuminated, and the objective lens 16 captures the image of the sample 11 and guides it to the eyepiece 18 from the observation optical axis X of the split prism 17. The observer 19 observes the sample through the eyepiece lens 18. At the same time, sample 1
The image of No. 1 is guided to the optical path 31 of the adapter body 30 from the imaging optical axis X ′ of the split prism 17. This adapter body 3
The image guided to 0 is reduced by the neutral density filter 33,
Observation image data is acquired by being projected onto the image pickup device 21 via the projection lens 35. This observation image data is automatically light-adjusted by, for example, an automatic gain control function and displayed on a monitor.

At this time, of the incident light reflected on the sample 11, the reflected light reflected on the surface of the image pickup device 21 again passes through the neutral density filter 33, is attenuated, and is guided to the split prism 17. The reflected light reflected by the surface of the split prism 17 again passes through the neutral density filter 33, is dimmed, and is guided onto the image sensor 21 via the projection lens 35. In this way, by repeatedly passing the dimming of the reflected light, a high-quality observation image can be obtained on the monitor (not shown).
Displayed above, high-precision observation is realized.

Here, since reflection does not occur on the surface of the neutral density filter 33 of the reflected light, the neutral density filter 33 is tilted with respect to the image pickup optical axis X ', and thus the observed image is observed. The effect is dimmed.

For example, when an ND filter having a spectral transmittance of 50% is used as the neutral density filter 33, the light incident from the observation optical axis X'is halved by the neutral density filter 33.
The light is dimmed to enter the image sensor 21 through the projection lens 35. Here, the image pickup device 21 has a sufficiently wide range of light receiving sensitivity as compared with human eyes, and its observation image data is automatically dimmed by, for example, an auto gain control function and displayed on the monitor (not shown). As a result, there is almost no effect on the observed image.

In this observation state, the reflected light reflected on the surface of the image pickup device 21 travels in the direction reverse to the image pickup optical axis X ',
The light passes through the neutral density filter 33, is guided to the split prism 17, is reflected by the surface of the split prism 17, is transmitted through the neutral density filter 33 again, and is incident on the image sensor 21. Since this reflected light is transmitted through the neutral density filter 33 twice,
It is reduced to 1/4 of the original light intensity.

Further, when the monitor image is dark, such as when the TV camera 20 having a narrow light receiving sensitivity range of the image pickup device 21 is used, the neutral density filter 33 of the adapter body 30 is
The observation image is acquired by replacing with the one having the optimum spectral transmittance.

Then, the neutral density filter may be detached from the adapter body 30 for observation in accordance with the image pickup performance of the TV camera 20 attached to the camera attachment portion 382 of the mount member 38. In this case, the adapter body 30
Loosen the clamp screw 40 screwed into the screw hole 39 of
The mount member 38 is rotationally adjusted to move and adjust in the direction of the imaging optical axis X ′, and the optical path length is adjusted (parfocal adjustment) so that a desired observation image can be acquired.

As described above, the image pickup camera connection adapter for a microscope has the neutral density filter 3 interposed between the split prism 17 of the lens barrel 15 and the image pickup device 21 of the TV camera 20.
3 is housed and arranged in the adapter body 30 at a predetermined tilt angle with respect to the image pickup optical axis X ', and the light reduction filter 33 effectively reduces the light reflected by the surface of the image pickup device 21. did.

According to this, the spot flare phenomenon due to the reflected light on the surface of the image pickup device 21 can be prevented, and the characteristics of the image pickup device 21 of the TV camera 20 are not affected.
High-accuracy observation images can be easily obtained, and the observation accuracy can be improved. As a result, the observer 19 can freely set the TV camera 20 and acquire an observation image with high accuracy, and the usage pattern of the microscope can be diversified.

The present invention is not limited to the above-mentioned embodiment, but it is also possible to construct a neutral density filter as shown in FIG. 2, for example. However, in FIG. 2, the same parts as those in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted.

That is, in the adapter body 30, a guide through-hole portion 301 is formed in the middle portion thereof in the directions of arrows A and B orthogonal to the optical path 31 (direction orthogonal to the image pickup optical axis X ').
The slide member 41 which is formed on the through hole 301 and constitutes a neutral density filter is movably accommodated in the through hole 301. The slide member 41 has first to third openings 42, 43, 44 corresponding to the optical path 31 of the adapter body 30.
Are formed at predetermined intervals.

Of these, in the first and second openings 42 and 43, step portions 421 and 431 forming a filter portion are respectively formed with a predetermined inclination angle with respect to the image pickup optical axis X '. First and second neutral density filters 45 and 46 such as ND filters having different spectral transmittances are attached to the step portions 421 and 431 by using the pressing rings 47 and 47.
It is attached with a predetermined inclination with respect to. As the first and second neutral density filters 45 and 46, those having different spectral transmittances such as 50% and 25% are used.

In the above structure, when observing the sample 11, the slide member 41 is moved and adjusted in the directions of arrows A and B, and any one of the first to third openings 42, 43 and 44 of the slide member 41 is adjusted to the adapter body. The optical paths 31 of 30 are selectively opposed to each other. Then, in a state in which one of the first and second openings 42 and 43 is arranged to face the optical path 31 of the adapter body 30, the first and second neutral density filters 45 and 4 are provided.
Attenuation corresponding to the spectral transmittance of 6 is realized. Also, the third
In a state in which the opening 44 of the above is opposed to the optical path 31 of the adapter body 30, an observation image in which the reflected light is not dimmed is acquired in a usage pattern in which the filter is not interposed.

In the embodiment described in FIG. 2, the slide member 41 is arranged so as to be movable in the directions of arrows A and B with respect to the optical path 31 of the adapter body 30. , But not limited to this,
A plurality of filter portions are arranged in a disc-shaped turret member at predetermined intervals corresponding to the optical path 31 of the adapter body 30, and the turret members are rotationally adjusted to form a filter portion or an opening on the optical path 31 of the adapter body 30. To place,
It is also possible to configure the so-called turret structure.

Further, in each of the above-mentioned embodiments, the case where the optical element is constituted by using the neutral density filter 33 and the first and second neutral density filters 45 and 46 has been described, but the present invention is not limited to this. In addition, it is possible to use an optical element such as an IR cut filter.

Furthermore, the present invention is not limited to the above-mentioned respective embodiments, but in addition to this, as shown in FIG.
A similar effect is expected. However, in FIG. 3, the same portions as those in FIG. 1 described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

First, prior to describing the embodiment shown in FIG. 3, the operation of this embodiment will be described.

On the front surface of the light receiving surface of the image pickup element (the side on which light is incident), a glass plate having a substantially parallel flat surface shape is provided for protecting the light receiving surface. It is considered that the flare generated when the image pickup camera is connected to the microscope is mainly generated in the glass (or the glass block) having the substantially parallel plane. This is because the reflectance of the surface of this plane-parallel glass is relatively high. A part of the light incident on the light receiving surface is reflected by the plane-parallel glass. Then, the reflected light is reflected again toward the image pickup element by the lens of the microscope optical system and other optical elements. This is repeated multiple times, and so-called multiple reflection occurs. As a result, many spot-shaped flares (hereinafter referred to as spot flares) are generated.

At this time, if the reflectance of the surface of the plane-parallel glass is high, the light quantity (light intensity) of the spot flare also becomes large. Therefore, the spot flare is imaged together with the image. In particular, since the shape of the lens surface near the optical axis is close to a flat surface, bright spot flare is likely to occur near the optical axis. Therefore, in the present invention, an optical element having a predetermined spectral transmittance for light in a predetermined wavelength region is arranged between the microscope optical system and the image pickup element. As this optical element, a neutral density filter, for example, an ND filter is suitable. Therefore, the ND filter will be described as an example.

In the above arrangement, the multiple-reflected light passes through the ND filter many times each time it is reflected. Therefore, the light quantity of the multiple-reflected light is rapidly attenuated, and the light quantity of the spot flare is relatively reduced with respect to the light quantity of the image. Finally, the difference between the light quantity of the image and the light quantity of the spot flare becomes so large that the spot flare becomes inconspicuous. That is, according to the present invention, it is possible to obtain the same effect as that of lowering the reflectance of the parallel flat glass provided on the image pickup element. As a result, it is possible to realize an imaging camera that causes less spot flare at low cost.

Furthermore, the amount of light from the sample is limited by the ND filter. Therefore, it becomes possible to photograph a specimen that could not be photographed due to too high reflectance or spectral transmittance in the past.

The ND filter is classified into an absorption type and a reflection type. Of these, absorption type (colored glass type)
Impurities such as bubbles and lumps remain in the glass due to its manufacturing process and material characteristics. In the imaging camera of the present invention, N
The D filter is arranged at a position close to the light receiving surface (imaging surface) of the image sensor. Therefore, if the ND filter has such impurities, the impurities and the like may be reflected in the captured image.

Therefore, it is preferable to use a reflective type glass capable of using glass with a small amount of impurities as a substrate. By doing so, it is possible to reduce the appearance of impurities in the image.

The ND filter is preferably replaceable or removable. If the ND filter is removed from the optical path, a dark sample can be imaged as in the conventional case. Further, by disposing the ND filter in the optical path, it is possible to image a bright sample that could not be imaged in the past. In this way, the range of brightness that can be imaged (hereinafter referred to as the brightness range) is preferable because it is wider than the conventional range.

In order to obtain a remarkable effect in removing flare and expanding the brightness range, it is desirable that the ND filter has a spectral transmittance of 50 ± 10% or less.

More preferably, it is 25 ± 5% or less.

Further, the reflection type ND filter includes a metal film coating type and an interference film coating type. Among them, the metal film coated type is cheaper than the interference film coated type, but the surface reflectance is higher than the interference film coated type. On the contrary, the interference film coated type is slightly more expensive than the metal film coated type, but the surface reflectance is lower than the metal film coated type. Therefore, it is preferable to select the interference film coat type as the ND filter from the viewpoint that unnecessary reflection is not generated.

As described above, when comparing the interference film coat type and the metal film coat type, the surface reflection of the interference film coat type is much smaller. However, even with the interference film coat type, some surface reflection still occurs.
And this surface reflection also causes flare.

Therefore, it is preferable to arrange the coated surface of the ND filter so as to be inclined with respect to the optical axis. By doing so, spot flare due to surface reflection on the coated surface can be reduced. At this time, it is desirable that the inclination angle of the coated surface be such that the light reflected by the coated surface reaches outside the effective imaging range of the image sensor. However, if the tilt angle is too large, the space required to install the ND filter becomes large. As a result, the image pickup camera cannot be made compact. Also, the mount standard may not be met.

In the interference film coating type, the interference film is designed so that the optimum spectral transmittance characteristic can be obtained with respect to a light ray having a specific incident angle (in many cases, vertical incidence to the coating surface). There is. Therefore, if the tilt angle largely deviates from the specific angle, the optimum spectral transmittance characteristic cannot be obtained.

Therefore, in order to make the installation space of the ND filter as small as possible and to maintain the characteristics of the interference film with respect to the incident light ray angle, the ND filter is arranged so that the coated surface is inclined in the short side direction of the effective image pickup range. Is good.

In this case, it is desirable that the inclination angle of the coated surface satisfies the following conditional expression (1).

2 × L1 × tan2θ + L1 × tan4θ ≧ L2 / 2 (1) where L1 is the distance on the optical axis from the coated surface of the ND filter to the light receiving surface of the image sensor. L2 is the length in the short side direction (diagonal line) of the effective image pickup area on the light receiving surface of the image pickup element. Further, θ is an angle formed between the reference axis and the coated surface when the reference axis is a direction perpendicular to the optical axis.

The above condition (1) defines that the light reflected by the ND filter and traveling toward the image pickup device reaches the light receiving surface of the image pickup device only once. This point will be described with reference to FIG.

The light from the sample passes through the ND filter F and reaches the light receiving surface IM of the image sensor. Part of the arrived light (here, the light on the axis) is reflected by the surface of the plane-parallel glass P provided in front of the light receiving surface IM (light ray). Next, the light rays are incident on the coated surface of the ND filter (the surface coated with the interference film). here,
When the direction perpendicular to the optical axis (or the direction parallel to the light receiving surface of the light receiving surface IM) is the reference axis, the ND filter F is arranged so that the coated surface is inclined by the angle θ with respect to the reference axis. That is, the coated surface of the ND filter F and the surface of the plane-parallel glass P are not parallel to each other. Therefore, the light (light ray) incident on the coated surface is reflected (light ray) toward the light receiving surface IM at an angle of 2θ with respect to the optical axis.

The light ray traveling toward the light receiving surface IM is reflected by the surface of the plane-parallel glass P, and the ND filter F again.
Toward (ray). However, the coated surface is inclined with respect to the reference axis as described above. Therefore, the light ray is reflected at a larger angle than the light ray and travels toward the light receiving surface IM (light ray). As a result, the light ray traveling toward the light receiving surface IM passes outside the effective imaging range of the light receiving surface IM. Therefore, of the light rays incident on the light receiving surface IM, ND
The light reflected by the coated surface of the filter F is only light rays.

Thus, if the above conditions are satisfied, ND
The light reflected by the filter (axial light) reaches the light receiving surface of the image sensor only once. Moreover, the inclination angle of the coated surface of the ND filter can be small. Therefore, it is possible to minimize the occurrence of flare and reduce the ND filter arrangement space. Further, since the tilt angle can be made small, the spectral transmittance characteristic of the ND filter can be made substantially the same as the spectral transmittance characteristic when not tilted.

When the above conditions are not satisfied, the light (axial light) reflected by the coated surface of the ND filter and reaching the image pickup element is generated at least twice. As a result, many spot flares occur, which is not preferable.

The following conditions that approximate the above condition (1)
(1 ') can also be used.

[0062]           2 × L1 × tan4θ ≧ L2 / 2 (1 ') Further, it is preferable that the following condition (2) is satisfied.

L1 × tan2θ ≧ L2 / 2 (2) When the condition (2) is satisfied, the light traveling from the coated surface of the ND filter toward the image sensor, that is, the light beam of FIG. Does not reach. Therefore, the occurrence of spot flare can be suppressed. The above condition is N
This is suitable when there is enough space to arrange the D filter.

The ND filter can also serve as dustproof glass. As described above, the plane-parallel glass is provided in front of the light receiving surface of the image sensor. This plane-parallel glass is closer to the image position (light receiving surface) than the ND filter. Therefore, if there are dusts or scratches on the plane-parallel glass, they will be reflected in the image, which is a problem.

However, the presence of the ND filter makes it possible to prevent dust from adhering to the plane-parallel glass provided on the light-receiving surface and scratching the plane-parallel glass.

Further, in the case of the metal film coat type or the interference film coat type, the ND coat can be applied to the surface of another optical element. Therefore, the coat type is preferable in that the number of parts does not increase.

Usually, as an optical element capable of ND coating, there are a dustproof glass, a low-pass filter, an IR cut filter, and a plane-parallel glass for the light receiving surface. Therefore, at least one of the above optical elements may be provided with a metal film coat type or interference film coat type ND coat.

In a special case, there is a system in which the substantial resolution of the image pickup device is improved by moving the image pickup device and the image relatively and using special image processing. In this case, since the low-pass filter is basically not arranged, the optical element capable of ND coating is a dustproof glass, an IR cut filter, or a plane-parallel glass of the light receiving surface.

As described above, at least one of the above optical elements may be provided with the metal film coat type or interference film coat type ND coat.

The ND filter is preferably arranged at a position far from the light receiving surface. By doing so, even if scratches or attached dust on the ND filter are reflected in the image, the reflection can be made inconspicuous.

Next, an embodiment based on the concept of the above-mentioned operation will be described with reference to FIG. That is, the adapter body 50 is similarly provided with the optical path 501 corresponding to the imaging optical axis X ′ of the split prism 15. Then, at one end of the adapter body 50, a mount portion 502 for mounting a camera is provided on the outer peripheral portion of the adapter body 50 (see FIG. 8).
It is provided corresponding to the mounting part of
A concave first accommodating portion 51 is provided.

A screw hole 511 is provided in the inner wall of the first accommodating portion 51, and the screw hole 511 has a screw hole 511.
A screw portion (not shown for convenience of the drawing) provided on the outer peripheral wall of the element support frame 52 is screwed to insert the element support frame 52. An ND filter 49, which is an optical element, having a predetermined inclination angle with respect to the optical axis is housed and arranged in the element supporting frame 52, and the ND filter 49 can be inserted into and removed from the first housing portion 51 by adjusting the screwing. Is composed of.

The element support frame 52 is not limited to the insertable / removable structure by the screw structure with respect to the first accommodating portion 51. It can also be configured to do so.

At the other end of the adapter body 50, a lens barrel mounting dovetail 503 is provided on the outer peripheral portion thereof, and a second accommodating portion 53 is provided on the inner peripheral portion thereof. Then, the lens support frame 54 in which the projection lens group 541 is housed and arranged is inserted into the second housing portion 53. Lens support frame 5
A plurality of concave portions (not shown for convenience of illustration) for positioning are provided in the peripheral portion of the peripheral portion 4 at predetermined intervals.

A plurality of screw holes 504 for positioning are provided in the adapter body 50 with respect to the optical axis X'to correspond to the recesses (not shown) of the lens support frame 54,
The clamp screw 55 is screwed into these screw holes 504. The clamp screw 55 has a fitting portion 5 at its tip.
51 is provided, and the screw hole 504 of the adapter body 50 is provided.
The fitting portion 551 is screw-adjusted with respect to, and the fitting portion 551 is selectively fitted into a concave portion (not shown) of the lens support frame 54. In the fitted state of the fitting portion 551 of the clamp screw 55, the lens support frame 54 is positioned and assembled at a desired position in the second housing portion 53 of the adapter body 50.

With the above structure, the adapter body 50 has the dovetail 503 fitted in the dovetail groove (not shown) of the lens barrel 15, and the TV camera 20 can be attached to the mount portion of the lens barrel. The TV camera 20 is connected to 15. At this time, the clamp screw 55 is loosened, the parfocal adjustment of the TV camera 20 attached to the mount portion 501 is performed, and the clamp screw 55 is screwed in the adjustment completed state to perform mutual positioning.

In this embodiment, the element support frame 5
By accommodating and disposing 2 in the first accommodating portion 51 of the adapter main body 50 on the TV camera 20 side, the element support frame 52 can be easily inserted / removed and its easy handling is realized. Further, since the ND filter 49 is not arranged at the intermediate image forming position, there is an effect that it is less likely to be affected by dust and scratches.

Further, in the present embodiment, the ND filter 49 is arranged between the TV camera 20 and the lens support frame 54 in which the projection lens group 541 is arranged. It is also possible to set the diameter of the diameter to a minimum, which has an effect of promoting miniaturization.

Also in this embodiment, the ND is almost the same as in the embodiment shown in FIG.
A filter switching mechanism in which a plurality of filters 49 having different spectral characteristics are arranged side by side is assembled, and one of N
It is also possible to selectively arrange the D filter 49 on the optical axis for exchange.

Here, in the example of the embodiment,
The ND filter 49 is configured by using parallel plane glass with an interference film type ND coat. Optical axis X '
If the reference axis is in the direction perpendicular to, the ND filter 4
9 is disposed with an inclination angle θ = 2 ° with respect to this reference axis. Naturally, the coated surface 49a of the ND filter 49
Also has an inclination angle θ = 2 ° with respect to the reference axis. Also,
The inclination direction is a direction along the short side direction of the light receiving surface 21a.
Further, the distance L1 on the optical axis X ′ from the coated surface 49a of the ND filter 49 to the light receiving surface 21a of the image pickup device 21 is 13
mm. The length L2 of the short side of the effective image pickup range of the image pickup device 21 is 6.6 mm.

The spectral transmittance of the ND filter 49 is
50 ± 10 in the wavelength range of 500 nm to 600 nm
%. Here, the spectral transmittance characteristic of the ND filter 49 is shown in FIG.

The present embodiment satisfies the condition (1) but does not satisfy the condition (2). In order to satisfy the condition (2), it must be tilted by more than 7.2 °.

In the present embodiment, ND is performed so that the coated surface 49a is on the side opposite to the light receiving surface 21a (optical device side).
A filter 49 is arranged. Thereby, the coated surface 49a having high reflectance can be separated from the light receiving surface 21a.

The ND filter 49 can be inserted and removed. In this embodiment, the element support frame 52 is attached to the first accommodating portion 51 of the adapter body 50.
Therefore, by removing this element support frame 52,
The filter 49 can be replaced with one having a spectral transmittance characteristic different from that of the filter 49.

For example, instead of the ND filter 49, an ND filter 49 'having a spectral transmittance of 25 ± 5% in the wavelength range of 500 nm to 600 nm may be used. ND
The spectral transmittance characteristic of the filter 49 'is shown in FIG.

Even when the ND filter 49 (49 ') is replaced, the distance L1 from the coated surface 49a (49'a) to the light receiving surface 21a of the image pickup device 21 on the optical axis X', the inclination angle θ and the inclination. The direction is almost the same as that of the ND filter 49.

In the present embodiment having such a configuration, the mount portion 502 is used, for example, when a specimen is imaged.
It is used by connecting to the microscope as shown in FIG. According to this embodiment, first, the light from the sample that has passed through the microscope is attenuated by the ND filter 49 (49 '). The dimmed light reaches the light receiving surface 21a of the image sensor 21,
Form an image of the specimen. At this time, a part of the light reaching the light receiving surface 21a is reflected by the parallel flat glass (protective glass that protects the light receiving surface 21a) provided in front of the light receiving surface 21a, and returns to the microscope optical system. This reflected light repeats multiple reflections with the microscope optical system, but N times many times each time.
It passes through the D filter 49 (49 '). Therefore, the light quantity of the multiple-reflected light, that is, the flare light, is rapidly attenuated, and the difference between the light quantity of the image and the light quantity of the flare light becomes very large. As a result, the spot flare becomes relatively inconspicuous. In particular, when a sample having a high reflectance is photographed, the light from the sample is bright, so that the effect obtained by the ND filter 49 (49 ') is great.

Further, as the ND filter 49 (49 '), the one coated with an interference film is used. Therefore, unlike the absorption type filter, bubbles and lumps are less likely to be reflected in the captured image.

In addition, in the present embodiment, the ND filter 4
9 (49 ′) is arranged so as to be inclined with respect to the light receiving surface 21 a of the image pickup device 21 in the relative arrangement relationship as described above.
As a result, the number of times the light reflected by the coated surface 49a (49a ') reaches the light receiving surface is one or less, and flare can be suppressed. Furthermore, the ND filter 49
Since (49 ') is tilted in the short side direction of the effective image pickup range of the image pickup device 21, the tilt angle can be small, and the ND filter 49
The installation space of (49 ') can be made as small as possible.

Further, the ND filter 49 and the ND filter 4
Since 9'is configured to be replaceable by inserting / removing, the ND filter 49 or the ND filter 49 'having different spectral transmittance characteristics according to the brightness of the sample is used to image a sample of a wider range of brightness. You can

Further, in the present embodiment, the IR cut coat is applied to the low pass filter, but there are also cases where a low pass filter not applied with the IR cut coat is used. In this case, an IR cut filter may be similarly arranged instead of the ND filter 49 (49 ').
At that time, it is preferable to apply an ND coat to the surface opposite to the surface to which the IR cut coat is applied.

For example, as an optical element replacing the ND filter 49 (49 '), a filter having a spectral transmittance characteristic of a half value wavelength λc of 390 nm ≦ λc ≦ 440 nm shown in FIG. You may

In this example, the plane-parallel glass P was treated as if it had no antireflection coating. However, if the antireflection coating is applied, the effect of suppressing the occurrence of spot flare is great. Therefore, the spot flare can be further suppressed by combining the parallel flat glass having the antireflection coating and the ND filter.

By applying an antireflection coat,
It is expected that the cost of the image sensor will increase. However, the ND filter can be omitted in some cases. In this case, there is a possibility that the cost increase due to applying the antireflection coating can be offset by omitting the ND filter.
Further, by omitting the ND filter, downsizing and cost reduction can be achieved.

Further, the effect of tilting the optical element to reduce the spot flare caused by the surface reflection is not limited to the ND filter, but all the optical elements in the camera (IR cut filter or future It is not clear if it can be done, but even the protective glass for the light-receiving surface) is effective. Therefore, the above condition (1) or condition (2) may be applied to all the in-camera optical elements arranged in front of the light receiving surface.

In the above embodiment, the TV camera 20 is used as the image pickup camera, but the present invention is not limited to this, and a digital camera may be used.

Further, in the above-mentioned embodiment, the case where the invention is applied to the upright microscope is explained, but the invention is not limited to this.
In addition, it can be applied to an inverted microscope and is expected to have substantially the same effect.

Therefore, the present invention is not limited to the above-described embodiment, and other various modifications can be carried out at the stage of carrying out the invention without departing from the spirit of the invention. Further, the embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiments, the problems described in the section of the problem to be solved by the invention can be solved, and the effects described in the effects of the invention can be obtained. When the above is obtained, the configuration in which this constituent element is deleted can be extracted as the invention.

The present invention is based on the above-described embodiment. (1) A first connecting portion for connecting an optical device, a second connecting portion for connecting an image pickup camera, and the image pickup camera as described above. In a microscope imaging camera connection adapter including a projection optical system for projecting an optical image of an optical device and an optical element having a predetermined spectral transmittance, the optical element has a predetermined inclination angle with respect to an optical axis. Further, it is possible to provide an imaging camera connection adapter for a microscope, which is arranged so that it can be inserted and removed from the optical axis.

(2) To provide an imaging camera connection adapter for a microscope, wherein the optical element described in (1) is arranged between the projection optical system and the second connection section. You can

(3) It is possible to provide an image pickup camera connection adapter for a microscope characterized in that the optical elements described in (1) and (2) are arranged so as to satisfy the following conditional expressions.

2 × L1 × tan2θ + L1 × tan4θ ≧ L2 / 2 where L1 is the distance on the optical axis from the coated surface of the optical element to the light receiving surface of the image pickup element of the image pickup camera, and L2 is the light receiving surface of the image pickup element. Is the length of the diagonal line of the effective imaging range, and θ is the angle between the reference axis and the coated surface when the direction perpendicular to the optical axis is the reference axis.

(4) A first connecting portion for connecting an optical device, a second connecting portion for connecting an image pickup camera, a projection optical system for projecting an optical image of the optical device on the image pickup camera,
In a microscope image pickup camera connection adapter including an optical element having a predetermined spectral transmittance, the optical element has a predetermined inclination angle with respect to the optical axis, and is selectively exchanged on the optical axis. It is possible to provide an imaging camera connection adapter for a microscope characterized by the above.

(5) To provide an image pickup camera connection adapter for a microscope, wherein the optical element described in (4) is arranged between the projection optical system and the second connection portion. You can

(6) It is possible to provide an image pickup camera connection adapter for a microscope characterized in that the optical elements described in (4) and (5) are arranged so as to satisfy the following conditional expressions.

2 × L1 × tan2θ + L1 × tan4θ
≧ L2 / 2 where L1 is the distance on the optical axis from the coated surface of the optical element to the light receiving surface of the image pickup element of the image pickup camera, L2 is the length of the diagonal line of the effective image pickup range on the light receiving surface of the image pickup element, θ is an angle formed by the reference axis and the coated surface when the reference axis is a direction perpendicular to the optical axis.

[0108]

As described in detail above, according to the present invention, the image pickup camera for a microscope, which has a simple structure, reduces the spot flare phenomenon, and contributes to the acquisition of a high-quality observation image, is provided. A connection adapter can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an imaging camera connection adapter for a microscope according to an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an imaging camera connection adapter for a microscope according to another embodiment of the present invention.

FIG. 3 is a configuration diagram showing an imaging camera connection adapter for a microscope according to another embodiment of the present invention.

FIG. 4 is a diagram shown for explaining the relative positional relationship between the ND filter of FIG. 3 and the light receiving surface of the image sensor.

FIG. 5 is a characteristic diagram showing spectral transmittance characteristics with respect to wavelength of an ND filter according to an embodiment used in the present invention.

FIG. 6 is a characteristic diagram showing spectral transmittance characteristics with respect to wavelength of an ND filter according to another embodiment used in the present invention.

FIG. 7 is a characteristic diagram showing a spectral transmittance characteristic with respect to a wavelength of a filter according to another embodiment used in the present invention.

FIG. 8 is a configuration diagram shown for explaining a schematic configuration of a microscope in which a conventional imaging camera connection adapter for a microscope is mounted.

[Explanation of symbols]

10… Microscope body 11 ... Specimen 12 ... Stage 13… Lamp House 14 ... Revolver 15… Lens barrel 16 ... Objective lens 17 ... Split prism 18 ... Eyepiece 19 ... Observer 20 ... TV camera 21 ... Image sensor 21a ... Light receiving surface 30… Adapter body 31 ... Optical path 311 ... Step 312 ... Lens mounting part 32 ... Ant 33 ... neutral density filter 34 ... Holding ring 35 ... Projection lens 36 ... Holding ring 37 ... Guidance 371 ... Adjusting screw part 38 ... Mount member 381 ... Screw part 382 ... Camera mounting part 39 ... Screw hole 40 ... Clamp screw 301 ... Through hole 41 ... Slide member 42 ... First opening 421 ... Step 43 ... Second opening 431 ... Step 44 ... Third opening 45 ... First neutral density filter 46 ... Second neutral density filter 47 ... Holding ring 49, 49 '... ND filter 49a, 49a '... Court surface 50… Adapter body 501 ... Optical path 502 ... Mounting part 503 ... ants 504 ... Screw hole 51 ... First accommodation section 511 ... Screw part 52 ... Element support frame 53 ... Third storage unit 54 ... Lens support frame 541 ... Projection lens group 55… Clamp screw 551 ... Fitting part

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atsushi Yoneya             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. F-term (reference) 2H052 AD34 AD37 AF14                 2H083 AA05                 2H105 CC01                 5C022 AB13 AC42                 5C024 CX01 EX42 EX47 EX51

Claims (3)

[Claims] 1. A microscope image pickup having a first connection section connected to an optical device, a second connection section connected to an image pickup camera, and a projection optical system for projecting an optical image of the optical device onto the image pickup camera. In the camera connection adapter, on the imaging optical axis between the optical device and the imaging camera,
An imaging camera connection adapter for a microscope, wherein an optical element is arranged with a predetermined inclination angle with respect to the imaging optical axis. 2. The image pickup camera connection adapter for a microscope according to claim 1, wherein the optical element is provided so as to be freely inserted into and removed from an image pickup optical axis. 3. Any one of a plurality of optical element portions having different spectral transmittances and an aperture portion arranged at a predetermined interval on an image pickup optical axis between the optical device and the image pickup camera can be selectively arranged. The image pickup camera connection adapter for a microscope according to claim 1, further comprising a different element switching mechanism.