JPH02172437A - Ophthalmology imaging device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention is directed to an ophthalmological device having a photoelectric photographing optical system that displays the fundus image of the eye to be examined on a television monitor, and a photographing optical system that images the fundus image on a film. This invention relates to improvement of photographic equipment.

[Prior Art and Problems to be Solved by the Invention] Fundus cameras have been conventionally used to take photographs of fundus images in order to observe the condition of the fundus.

The simplest fundus camera is equipped with a photographic optical system for taking photographs and an observation optical system for visual recognition by the operator.

Recently, there has been an increasing trend in the number of fundus cameras equipped with a photoelectric photographing optical system equipped with an image receiving element such as a fuse and a television camera. The photoelectric photographing optical system is used to take photographs and store the fundus image as an electrical signal, or to display the fundus image on a television monitor in real time for alignment and observation.

By the way, focusing of the fundus camera is performed by moving a focusing lens provided in a common portion of each of the optical systems in the optical axis direction.

However, in general, in a fundus camera, the photoelectric photographic optical system and the photographic optical system have different magnifications, so the depth of focus at the image receiving portion is affected by the difference in F-number.

In other words, since the depth of focus is generally proportional to the F number of the optical system, if the aperture diameter is the same, then the depth of focus will be multiplied by v4 (focal length).
The larger the value, the deeper the depth of focus.

Therefore, even if a specific optical system is brought into focus by moving the common focusing lens, it is not necessarily guaranteed that other optical systems will be in focus.

[Object of the invention] This invention was made in view of the above problems, and
For ophthalmology, it eliminates the change in focus state due to the difference in F number between the photoelectric photography optical system and the photography optical system, and guarantees the focus of other optical systems by focusing on a specific optical system. The purpose is to provide photographic equipment.

[Means for Solving the Problems] An ophthalmological photographing device according to claim 1 includes a photoelectric photographing optical system and a photographing optical system, and includes a depth of focus of the optical system in at least one of the photographing optical systems. The ophthalmological photographing device according to claim 2 is characterized in that it is provided with an aperture whose aperture diameter can be selected so as to change the aperture diameter. The ophthalmological photographing apparatus according to claim 3 is characterized in that at least one of the photographing optical systems is provided with an exchange mechanism for selectively inserting a plurality of filters into the optical path. The present invention is characterized by having automatic selection means for automatically selecting a plurality of filters depending on the type of photography.

[Example] The present invention will be explained below based on the drawings.

(First example) FIG. 1 shows a first embodiment of the invention.

This fundus camera is equipped with an illumination system and a B imaging system. The illumination system has an observation illumination optical system and a photography illumination optical system, and the observation photography system has a photoelectric photography optical system, a photographic manipulation optical system, and an observation optical system.

The observation illumination optical system includes optical members such as an observation light source 1, an observation condenser lens 2, a half mirror 3, an illumination relay lens 4, a perforated mirror 5, and an objective lens 6. The illumination light from the observation illumination light source 1 is transmitted through the condenser lens 2.
The light is focused by the apertured mirror 5 via the half mirror 3 and the relay lens 4, and illuminates the fundus Ef of the eye E by the objective lens 6.

The photographing illumination optical system includes a strobe tube 7 and a photographing condenser lens 8, and shares an optical path with the observation illumination system after the half mirror 3. The flash light from the strobe tube 7 illuminates the fundus Ef through optical members from the photographing condenser lens 8 to the objective lens 6.

The observation and photographing optical system has an objective lens 6, an aperture mirror 5, an observation aperture 9, a focusing lens system 1O1, and an imaging lens system 11 as common parts. The optical path of the reflected light from the fundus Ef is changed by the quick return mirror 12 between observation and photography.

During normal observation, the quick return mirror 12 is located at the position indicated by the broken line and withdrawn from the optical path, and the reflected light enters the observer's eye via the observation optical system consisting of the mirror 13 and the eyepiece 14.

When photographing, the quick return mirror 12 momentarily rotates to the position shown by the broken line in the figure, and the reflected light is reflected downward in the figure.The reflected light is divided by a half mirror 15, and the transmitted light is divided by a relay lens 16, The light reflected by the half mirror 15 is guided to a photoelectric photographing optical system consisting of a first filter 17 and a television camera 18, and enters a photographing optical system consisting of a relay lens 19, a second filter 20, and a film 21.

Therefore, since the same fundus image is formed on the television camera 18 and the film 21, by displaying the image taken by the television camera on a television monitor (not shown), it is possible to check whether the photographing was successful without developing the film. It is possible to judge whether

In addition, each photographing optical system includes a television camera 18 and a film 2.
The magnifications of the fundus images formed in 1 can be adjusted independently.

Further, in the relay lens 16.19 of each photographic optical system, apertures 18a and 19a are provided at positions that serve as aperture stops, and these apertures 16a and 19a
and the aforementioned observation system diaphragm 9 are arranged at a position optically conjugate with the anterior segment F of the subject's eye via their respective optical systems.

Note that these diaphragms may have a configuration in which the aperture diameter can be continuously adjusted as a variable diaphragm, or may have a configuration in which a plurality of fixed diaphragms having different aperture diameters are selectively inserted into the optical path.

Next, the focus correction function of the ophthalmological photographing apparatus having the above configuration will be explained.

As mentioned above, the depth of focus changes due to changes in magnification, etc.

In the above-described apparatus, the magnification of each photographing optical system is changed independently as necessary, and therefore the ratio of the depth of focus of each photographing optical system differs depending on the case.

Therefore, even if the observation optical system focuses on the fundus while observing, the television camera 18 or the film 2
There is a possibility that the fundus image formed on 1 may be out of focus. In the conventional fundus photographing device, only the observation aperture 9 is provided, and the depth of focus of each optical system cannot be adjusted independently.

In the apparatus of this embodiment, each photographic optical system is provided with independently adjustable variable apertures lea and 19a.
By adjusting these apertures and changing the aperture diameter of the optical system, the depth of focus can be adjusted independently.

Therefore, through such adjustment, the depth of focus of both optical systems can be made to match or exceed the depth of focus of the observation optical system.
By checking the focusing state of the w1 sensing optical system, it is possible to guarantee the focusing state of each photographing optical system.

By the way, although the television camera 18 and the film 21 each have an appropriate exposure light amount, the appropriate balance of the exposure amount may be lost due to a change in the light amount due to the adjustment of the aperture. If no corrective measures are taken here, a situation may arise in which, for example, even if the amount of light reaching the television camera is sufficient, the amount of light reaching the film 21 is insufficient.

Therefore, in this device, the first,
The second filters 17 and 20 are replaceable to eliminate the influence of the change in light amount due to the above-mentioned aperture adjustment and to correct the color temperature.

Although the amount of light and wavelength required for color photography and fluorescence photography are significantly different, by automatically changing the filter and adjusting the light amount and wavelength, it is possible to perform color photography and fluorescence photography with just one color television camera. It can be performed.

(Second example) FIG. 2 shows a second embodiment of the invention.

The ophthalmological photographing apparatus shown in this example has an observation optical system and a photographing optical system integrated into a 35 mm camera, and a light flux is constantly guided to the photoelectric photographing optical system. The other configurations are almost the same as the device of the first implementation.

That is, the reflected light from the fundus Ef is divided into two by the light-receiving half mirror 15 via the lens group. Half mirror 1
The light beam reflected from the fundus 5 reaches the television camera 18 via the mirror η and the television relay lens 16.

Furthermore, during observation, the light beam transmitted through the half mirror 15 is reflected by the quick return mirror 12 located at the solid line in the figure, is converted into an erect image by the pentagonal prism 23, and is transmitted to the observer's eye via the eyepiece lens 14. to go into. When photographing, the quick return mirror 12 is flipped up to the position indicated by the broken line in the figure, and the light beam reaches the film 2X.

In this example, the aperture that adjusts the depth of focus balance of each photographic optical system is the TV relay lens 16 of the photoelectric photographic optical system.
It is only located inside. This is because photoelectric photographic optical systems generally have a lower magnification and shallower depth of focus than photographic optical systems, so even if the photoelectric photographic optical system can only be adjusted in the direction of deepening the depth of focus, the depth of focus is not balanced. This is because it can perform the adjustment function.

Note that since the photographing optical system and the observation optical system have a common optical system and cannot independently adjust the magnification, there is no need to consider adjusting the depth of focus balance between these optical systems.

According to the above configuration, the fundus image photographed by the television camera 18 can be constantly displayed on a television monitor (not shown), and when configured as a non-mydriatic fundus camera using an infrared light source as the illumination light source l. The device can also be aligned while observing the monitor.

[Effect] As explained above, according to the present invention, by adjusting the aperture provided within the scanning optical system, the depth of focus of the optical system can be adjusted, and the focal depth of the plurality of photographic optical systems can be adjusted. You can adjust the depth balance to match. Therefore, by focusing the - optical system, it is possible to ensure the in-focus state of the other optical systems as well.

Furthermore, when filters that change the amount of received light are selectively provided in these optical paths, it is possible to compensate for changes in the amount of light due to line and aperture adjustments, and to ensure an appropriate balance of the amount of received light for each light receiving means.

Furthermore, if these filters are configured to be automatically selected depending on the type of photography, it is possible to guide the light beam with the optimum light amount and wavelength to the light receiving means according to the type of photography.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a first embodiment of an ophthalmologic photographing apparatus according to the present invention, and FIG. 2 is an explanatory diagram showing a second embodiment. E...Eye to be examined Ef...Fundus 6...Objective lens 18...Television camera (imaging element of photoelectric photography optical system) 21...Film (image receptor of photography optical system) 16
a...TV aperture (variable aperture)

Claims (3)

[Claims] (1) It is equipped with a photoelectric photographic optical system and a photographic optical system, and at least one of the photographic optical systems is provided with an aperture whose aperture diameter can be selected to change the depth of focus of the optical system. An ophthalmological imaging device featuring: (2) At least one of the photoelectric photographic optical system and the photographic optical system is provided with an exchange mechanism for selectively inserting a plurality of filters into the optical path. The ophthalmological imaging device described. (3) The ophthalmologic photographing apparatus according to claim 2, wherein the exchange mechanism includes automatic selection means for automatically selecting the plurality of filters depending on the type of photographing performed by both photographing optical systems.