JP2000197610A - Ophthalmologic photographing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely correct the position of an exit pupil by simple constitution. SOLUTION: The image of an eyground illuminated by a light flux emitted from a stroboscopic light source 14 passes through an objective lens 12, the hole of a perforated mirror 17, a photographic diaphragm 18, a focus lens 19 and a photographic lens 20 and after temporarily forming an image at a primary image forming position P, the image passes through a lens 26 to be projected to be far infinitely by a collimator lens 27. Then the image is reflected by a variable prism, and passes through an image forming lens 29, enters a color dividing prism 30 to be decomposed to be respective colors of blue, green and red. They respectively form images at image pickup elements 31a to 31c and converted to electric signals, which are converted to digital image data to be recorded in a recording medium by an image recording means and this recorded eyeground image Er' is reduced on a television monitor 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic photographing apparatus used for photographing a fundus image or the like in an ophthalmic clinic or the like.

[0002]

2. Description of the Related Art Conventionally, an ophthalmologic photographing apparatus has a focus adjusting means or a magnification changing means disposed behind a photographing aperture to observe a once formed fundus image using an eyepiece optical system, or to use an image forming optical system. And is used to form an image on the image sensor. In this case, an eyepiece or an imaging lens having a large aperture is used because the exit pupil position, which is an image of the photographic stop, changes due to focus adjustment by the focus adjustment unit or magnification change by the zooming unit.

Further, when a camera having a color separation optical system is used as an image pickup means, color shading occurs when the position of the exit pupil changes from infinity. Therefore, when a television camera is mounted via a lens of the television adapter, different television adapters must be used in accordance with different exit pupil positions for each ophthalmologic photographing apparatus. As this method, a method is known in which the power of a field lens disposed at an image forming position is changed to correct a change in the exit pupil position caused by a focus adjusting unit or a zooming unit.

[0004]

However, in the above-mentioned conventional example, in order to change the power of the field lens by replacing the lens, a plurality of lenses must be driven, and these lenses must be arranged. Space is required, and the configuration becomes complicated. Further, when the power is changed by exchanging the lens, the power can be changed only in steps, so that there is a problem that the exit pupil position cannot be accurately corrected. Further, a lens that continuously changes power is also known, but it is not yet at a practical level in terms of size, imaging performance, and cost. Fluctuates.

An object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide an ophthalmologic photographing apparatus that can accurately correct the exit pupil position with a simple configuration.

Another object of the present invention is to provide an ophthalmologic photographing apparatus capable of continuously correcting the exit pupil position.

[0007]

According to the present invention, there is provided an ophthalmologic photographing apparatus for illuminating an eye to be inspected, and a fundus image illuminated by the illuminating means is infinitely transmitted through a photographing stop. A first photographing optical system that projects far, a second photographing optical system that forms the fundus image on an image sensor, and photographing condition changing means provided in the first or second photographing optical system;
An optical path length changing means for correcting a change in the exit pupil position caused by a change in the imaging condition by the imaging condition changing means by changing an optical path length between the first and second imaging optical systems. I do.

An ophthalmologic photographing apparatus according to the present invention includes an illuminating means for illuminating an eye to be examined, and a first photographic optical system for projecting a fundus image illuminated by the illuminating means to a substantially infinite distance through a photographic stop. A second photographing optical system that forms the fundus image on an image sensor, a photographing condition changing unit provided in the first or second photographing optical system, and a change in photographing conditions by the photographing condition changing unit. The change of the exit pupil position is determined by the first and second
And optical path length changing means for correcting by continuously changing the optical path length between the photographing optical systems.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the illustrated embodiment. FIG. 1 is a perspective view of a fundus camera according to a first embodiment. A movable stage 2 is mounted on a base 1 so as to be movable three-dimensionally. On the movable stage 2, a measuring unit main body 3 having a built-in optical system, a television monitor 4, an operation stick 6 having a photographing switch 5 at a tip, and a variable power switch 7 are arranged. Then, on the front of the base 1, MO, M
Image recording means 8 which is a drive device for recording an image on a recording medium capable of holding data even without external power supply, such as D, DVD-RAM, VTR tape, hard disk, etc.
The focus knob 9 is provided on the side surface of the measurement section main body 3.
Is provided.

FIG. 2 shows a configuration diagram of an optical system in the measuring section main body 3. An optical path from an observation light source 11 such as an IRED that emits infrared light to an objective lens 12 facing the eye E is shown in FIG. A condenser lens 13, a photographing strobe light source 14 that emits visible light, an aperture 15 having a ring-shaped aperture, a lens 16, and a perforated mirror 17 are sequentially arranged to constitute a fundus illumination unit.

A fundus observation means is provided on the optical path behind the perforated mirror 17, and has a photographing diaphragm 18 provided in the hole of the perforated mirror 17, and a lens position detecting means 19a, and a focus movable on the optical path. Lens 19, photographing lens 2
0, wavelength division mirror 2 that reflects infrared light and transmits visible light
1, a mirror 22, lenses 23 and 24, and photographing means 25 are sequentially arranged.

On the optical path when the wavelength division mirror 21 is retracted from the optical path, a field lens 26, a collimator lens 27 having a focal position at a primary image forming position P of the fundus image, and a driving unit 28a are used to move the mirror in the horizontal direction. The movable prism 28 which moves to form the optical path length correcting means is arranged,
Shooting aperture 18, focus lens 19, shooting lens 2
A first photographing optical system is constituted by 0, the field lens 26, and the collimator lens 27.

Further, in the reflection direction of the movable prism 28,
Lens 29, color splitting prism 3, which is the second photographing optical system
A color imaging means 32 including zero and three imaging elements 31a to 31c is arranged. These imaging devices 31a to 31a to
31c is located at the rear focal position of the lens 29, so that the fundus image is once formed at the primary imaging position P, then projected to infinity by the collimator lens 27, and the imaging elements 31a to 31c Are formed on the image plane. The exit pupil, which is an image of the photographing aperture 18, substantially coincides with the front focal point of the lens 29, and a telecentric optical system that forms an image at infinity after exiting the lens 29 is formed.

The outputs of the image pickup means 25 and the color image pickup means 32 are connected to an image control means 33. The output of the image control means 33 is an operation control section 34 for controlling the whole operation, the television monitor 4, the image storage means 8, It is connected to a television monitor 35. The output of the operation control unit 34 is connected to the strobe light source 14 via the strobe light emission control circuit 36, and the outputs of the photographing switch 5 and the zoom switch 48 are connected to the operation control unit 3.
4 is connected.

The movable prism 28 includes a focus lens 19
Even if the exit pupil position moves due to the change in the position, the operation control unit 34 interlocks with the position of the focus lens 19 so that the image forming position of the photographing aperture 18 substantially matches the front focal position of the lens 29. It is designed to be driven.
The image control means 33 has a function of controlling the image recording means 8 to write or read an image output from the color imaging means 32 to or from a recording medium of the image recording means 8.

With such a configuration, the photographer sits the subject in front of the fundus camera, and firstly, the fundus Er of the eye E to be examined.
The eye E and the fundus camera are aligned while observing with infrared light. Infrared light emitted by the observation light source 11 is condensed by the condenser lens 13, passes through the imaging light source 14, passes through the opening of the ring-shaped aperture stop 15, passes through the lens 16, and mirrors around the perforated mirror 17. Illuminates the fundus Er through the objective lens 12 and the pupil Ep of the eye E to be examined.

Thus, the fundus Er illuminated with infrared light
Are reflected by the objective lens 12, the aperture 18 of the aperture of the perforated mirror 17, the focus lens 19, and the imaging lens 20.
And is reflected downward by the wavelength division mirror 21 for infrared light, further reflected to the left by the mirror 22, passes through the field lens 23, forms an image on the imaging surface of the imaging means 25 by the imaging lens 24, and Converted to a signal. This signal is input to the image control means 33, and the fundus image Er ′ is displayed on the television monitor 4. The photographer uses this TV monitor 4
Operate the operation stick 6 while watching the fundus image Er ′ reflected on
The measurement unit main body 3 and the subject's eye E are aligned, and the focus shooting range using the focus knob 4 is checked.

At this time, the position of the focus lens 19 is always detected by the lens position detecting means 19a.
When detecting the position of the focus lens 19, the operation control unit 34 calculates the position of the movable prism 28 corresponding to the position of the focus lens 19 by a procedure stored in advance in the memory 34a of the operation control unit 34, 2
The movable prism 28 is moved to the position calculated by 8a. After confirming that the photographing range, position, and focusing are good, the photographer operates the photographing switch 5 to photograph a still image.

The operation control unit 34 which has detected the input to the photographing switch 5 starts the light accumulation of the image pickup devices 31a to 31c, sends a light emission signal to the strobe light emission control circuit 36, and emits light from the strobe light source 14. The light beam emitted from the strobe light source 14 passes through the opening of the ring-shaped aperture stop 15, passes through the lens 16, is reflected to the left by the perforated mirror 17, passes through the objective lens 12, passes through the objective lens 12, similarly to the observation light.
Illuminates the fundus Er through the pupil Ep of the eye.

The reflected image of the fundus Er illuminated in this way passes through the objective lens 12, the photographic stop 18 in the hole of the perforated mirror 17, the focus lens 19, the photographic lens 20, and the wavelength division mirror 21 for visible light. , Once formed at the primary imaging position P, projected through a lens 26 to infinity by a collimator lens 27, reflected upward and further leftward by a movable prism 28, and passed through an imaging lens 29 to a color splitting prism 30. The light enters, is decomposed into red, green, and blue colors, forms an image on the imaging elements 31a, 31b, and 31c, and is converted into an electric signal.

The electric signal is converted into digital image data by the image control means 33 and is recorded on a recording medium by the image recording means 8, and at the same time, the fundus image Er ′ is reproduced on the television monitor 35. At this time, the movable prism 28 for correcting the optical path length is set in advance so that the image of the photographing diaphragm 18 coincides with the front focal point of the lens 29, and the principal ray emitted from the lens 29 is parallel. For this reason, in the color separation prism 30, there is no shift in the wavelength of color separation due to the portion of the fundus image Er ', and thus no color shading occurs.

FIG. 3 shows the configuration of the second embodiment.
In the second embodiment, the movement of the exit pupil caused by the movement of the focus lens 19 is corrected by using the movable prism 28. However, in the second embodiment, the movement of the exit pupil caused by the magnification change by the variable magnification lens is corrected. The same members as those in FIG. 1 are denoted by the same reference numerals.

The taking lens 20a and the magnifying taking lens 20b
Are configured to be alternately arranged on the optical path. The optical path length correction optical member 40 is disposed on the optical path behind the collimator lens 27 so as to be freely inserted and removed. When the taking lens 20a is disposed on the optical path, the optical path length correction optical member 40 is also disposed on the optical path. When the magnifying lens 20b is disposed on the optical path, it is configured to separate from the optical path. In addition, a lens 41, an aperture 42 having a shutter function, a lens 43, and an image sensor 44 are integrally housed in a housing to constitute a digital camera 45.

When an optical system having an aperture 42 is connected to a fundus camera in such lenses 41 and 43 and the fundus is photographed, the exit pupil of the optical system of the fundus camera moves.
The diaphragm 42 blocks the light beam, and the peripheral light amount is reduced or the image is blurred. Therefore, the optical path length correcting optical member 40
Is used to prevent the light beam from being blocked even when the positions and focal lengths of the photographing lenses 20a and 20b are changed so that the image of the photographing diaphragm 18 is always formed near the diaphragm 42.

First, when photographing is performed using the photographing lens 20a, the fundus Er is irradiated with infrared light similarly to the first embodiment.
The photographing switch 5 is operated after confirming that the photographing range and the focus state are good. Upon detecting the input to the photographing switch 5, the operation control unit 34 opens the shutter of the digital camera 45, opens the aperture 42 to a certain size, starts the light accumulation of the image sensor 44, and controls the flash control circuit 36. Sends the light emission signal, and the strobe light source 14
Emits light.

The light beam emitted from the strobe light source 14 passes through the opening of the ring-shaped aperture stop 15 like the observation light, passes through the lens 16 and is reflected to the left by the perforated mirror 17.
The fundus Er is illuminated from the pupil Ep through the objective lens 12. The fundus image illuminated in this way is the objective lens 1
2. After passing through the photographic stop 18, the photographic lens 20a, and the wavelength division mirror 21 in the hole of the perforated mirror 17, and once forming an image at the primary image forming position P, the light passes through the field lens 26 and is infinite by the collimator lens 27. The image is projected far away, passes through an imaging lens 41, a diaphragm 42, and a lens 43 in a digital camera 45 via an optical path length correcting means 40, forms an image on an image sensor 44, and is converted into an electric signal. The electric signal is converted into digital image data by the image control means 33 and is recorded on the recording medium by the image recording means 8, and at the same time, the fundus image Er ′ is reproduced on the television monitor 35.

Next, the magnification switch 7 is operated in order to perform enlarged photographing. Upon detecting the input to the variable power switch 7, the operation control unit 34 retracts the photographing lens 20a out of the optical path, inserts the magnifying photographing lens 20b for magnifying photographing into the optical path, and moves the optical path length correction unit 40 out of the optical path. evacuate. The photographer observes the fundus oculi Ea with infrared light in the same manner as in the first embodiment, and after confirming that the photographing range and the state of focus are good,
The photographing switch 5 is operated.

Upon detecting the input to the photographing switch 5, the operation control unit 34 opens the shutter of the digital camera 45 to open the aperture 42 to a certain size, starts the light accumulation of the image pickup device 44, and emits a strobe light. A light emission signal is sent to the control circuit 36, and the strobe light source 14 emits light. Similarly to the observation light, the light beam emitted from the strobe light source 14 passes through the opening of the ring-shaped aperture stop 15, passes through the lens 16, is reflected to the left by the mirror around the perforated mirror 17, and passes through the objective lens 12. The fundus Er is illuminated from the pupil Ep.

The reflected image of the fundus Er illuminated in this manner passes through the objective lens 12, the photographic aperture 18 in the hole of the perforated mirror 17, the photographic lens 20b, and the wavelength division mirror 21, and reaches the primary imaging position P. Once formed, the light passes through the lens 26 and is projected to infinity by the collimator lens 27.
Lens 41, aperture 42, lens 4 of digital camera 45
3 and forms an image on the image sensor 44 and is converted into a digital signal. The image control means 33 records this digital signal on a recording medium by the image recording means 8.

At the same time, the enlarged fundus image Er 'is reproduced on the television monitor 35. Also in this case, the image of the photographing diaphragm 18 is always changed by the optical path length correcting optical member 40.
Since all the light beams are formed in the vicinity of 2, the light beam can pass through the stop 42, and the image is not blurred or the light amount becomes uneven.

In the second embodiment, the optical path length is corrected by inserting and removing the optical path length correcting optical member 40 on the optical path.
Like the movable prism 28 shown in FIG. 1, the optical path length between the collimator lens 27 and the lens 41 may be corrected by moving the digital camera 45 on the optical path. This makes it possible to continuously correct the optical path length. For example, when the magnification of the photographing lens 18 changes continuously with a zoom lens, or when the focus lens 19 moves, the exit pupil position is continuously changed. Even if it changes, the exit pupil position can be accurately corrected.

FIG. 4 shows a prism of the third embodiment.
(a) As shown in FIG.
a, 46b are arranged such that their slopes face each other,
By moving the prisms 46a and 46b in parallel with the slope as shown in FIG. 3B, the optical path length between the surfaces S1 and S2 can be changed. Therefore, by arranging these prisms 46a and 46b instead of the optical path length correcting optical member 40 shown in FIG. 3, it is possible to continuously correct the exit pupil position.

FIG. 5 shows a television adapter according to a fourth embodiment. As shown in FIGS. 5A and 5B, a lens 26, a collimator lens 27 and a lens 29 are arranged in an independent housing, and The TV adapter is attached to the mount of the fundus camera and connected to the TV camera by the mount 48. As described above, when the television camera is attached to the fundus camera via the television adapter, the options of the fundus camera and the television camera are increased, and the usability is improved.

At this time, since the fundus camera also has a different exit pupil position depending on the model, color shading or uneven brightness occurs in the image. For this purpose, the lens 29 and the camera mount 48, and in some cases, the camera mounted on the camera mount 48 are integrally movable so that the distance between the lens 27 and the lens 29 can be changed, so that only the exit pupil position Can be adjusted, so that it can be attached to various fundus cameras. The same effect can be obtained even if the distance between the lens 27 and the lens 29 is adjusted according to the magnification of the fundus camera. The combination of the techniques of the imaging unit 44 and the optical path length correcting optical member 40 is as follows.
It does not have a specific relationship, and similar effects can be obtained by combining different means.

[0035]

As described above, the ophthalmologic photographing apparatus according to the present invention corrects the change of the exit pupil position caused by the change of the photographing condition by the change of the optical path length between the photographing optical systems. Even when using an image pickup device having an aperture, it is possible to prevent the occurrence of color shading, and even when using an image pickup device with a built-in optical system and aperture, an image of a photographing stop is held near the stop position of the image pickup device. As a result, an image without uneven brightness can be obtained.

In the ophthalmologic photographing apparatus according to the present invention, the change of the exit pupil position caused by the change of the photographing condition is continuously changed by changing the optical path length between the photographing optical systems. Even when moving continuously, accurate correction can be performed without using expensive parts. Even when the exit pupil position changes continuously with a change in magnification using a zoom lens as an imaging lens, expensive parts can be used. The correction can be made with high accuracy without using.

[Brief description of the drawings]

FIG. 1 is a perspective view of a fundus camera according to a first embodiment.

FIG. 2 is a configuration diagram.

FIG. 3 is a configuration diagram of a second embodiment.

FIG. 4 is a configuration diagram of a prism according to a third embodiment.

FIG. 5 is a configuration diagram of a television adapter according to a fourth embodiment.

[Explanation of symbols]

 Reference Signs List 3 Measurement unit main body 4, 35 TV monitor 5 Shooting switch 6 Control rod 7 Zoom switch 8 Image recording means 11 Observation light source 14 Strobe light source 17 Perforated mirror 18, 42 Aperture 20, 20a, 20b Imaging lens 21 Wavelength division mirror 25 , 32, 44 Imaging means 28 Movable prism 30 Color separation prism 31a to 31c Imaging element 33 Image control means 34 Operation control unit 36 Strobe light emission control circuit 40 Optical path length correction optical member 45 Digital camera 46a, 46b Wedge prism 47, 48 Mount

Claims (8)

[Claims] An illumination unit configured to illuminate an eye to be inspected; a first imaging optical system configured to project a fundus image illuminated by the illumination unit to approximately infinity via an imaging stop; A second photographing optical system for imaging, photographing condition changing means provided in the first or second photographing optical system, and a change in the exit pupil position caused by changing the photographing condition by the photographing condition changing means. And an optical path length changing means for correcting by changing an optical path length between the second imaging optical systems. 2. The ophthalmologic photographing apparatus according to claim 1, wherein said photographing condition changing means is a focus adjusting means. 3. The ophthalmologic photographing apparatus according to claim 1, wherein the photographing condition changing unit is a photographing magnification changing unit. 4. The ophthalmologic photographing apparatus according to claim 1, wherein said imaging means is a three-panel camera having a color separation optical system. 5. An illuminating means for illuminating an eye to be inspected, a first imaging optical system for projecting a fundus image illuminated by the illuminating means to approximately infinity via an imaging stop, and connecting the fundus image to an image sensor. A second photographing optical system for imaging, photographing condition changing means provided in the first or second photographing optical system, and a change in the exit pupil position caused by changing the photographing condition by the photographing condition changing means. And an optical path length changing means for correcting by continuously changing the optical path length between the second imaging optical systems. 6. The ophthalmologic photographing apparatus according to claim 5, wherein said photographing condition changing means is a focus adjusting means. 7. The ophthalmologic photographing apparatus according to claim 5, wherein said photographing condition changing means is a photographing magnification changing means. 8. The ophthalmologic photographing apparatus according to claim 5, wherein said imaging means is a three-panel camera having a color separation optical system.