JPH11104084A - Fundus camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fundus camera having both mydriatic and non-mydriatic functions, which can be switched from one to the other by simple means. SOLUTION: Light from an observation light source LA is applied via an illuminating system to the fundus oculi of the eye to be examined, and the light reflected from the fundus oculi is focused via a focusing optical system to observe the fundus oculi. A fundus camera can be switched between mydriatic and non-mydriatic functions, and the emission wavelength and the diffusion characteristic of the observation light source are changed as the function is changed. The emission wavelength of the observation light source is changed by inserting a visible light transmitting filter F1 or an infrared light transmitting filter F2 into an optical path, and the diffusion characteristic of the observation light source is changed by inserting and removing optical elements G1, G2 having first and second diffusing functions into and from the optical path. This constitution allows good observation of the fundus oculi without the possibility of making illumination uneven, whether the fundus camera is switched to the mydriatic function or non-mydriatic function.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera, and more particularly to a fundus camera in which a mydriatic retinal camera and a non-mydriatic retinal camera are integrated and the functions of the binocular fundus cameras can be switched.

[0002]

2. Description of the Related Art Generally, a mydriatic retinal camera and a non-mydriatic retinal camera are known as cameras for imaging a fundus image by forming reflected light from the fundus illuminated by light from a light source. I have. The mydriatic retinal camera mainly uses a visible light source, can capture a wide angle of view, and has a tilt mechanism of the camera itself to enable capturing of every corner of the fundus. The drawback of the mydriatic retinal camera is that it is necessary to dilate the eye to be measured, which imposes a great burden on the subject. On the other hand, a non-mydriatic fundus camera uses infrared light as a light source, so it is not necessary to dilate the subject's eye.However, the angle of view is not as wide as the mydriatic type, and imaging around the fundus macula is possible. Focus control is performed by projecting an infrared light focus index onto the fundus without using visible light for focusing. In addition, by placing a ground glass on the observation light source, or by making one surface of the condenser lens used for the observation light source into a slip surface, illumination unevenness during observation (such as an image of a filament of a lamp, Attempts have been made to mitigate such problems as the central part being too bright.

[0003]

In the conventional fundus camera, each of the above functions is realized as a mydriatic retinal camera or a non-mydriatic retinal camera. Since it was configured as an observation light source, it was only necessary to reduce the above-mentioned illumination unevenness exclusively for each light source, but in a fundus camera where both functions can be obtained by one unit, infrared light is more diffusive. Therefore, there is a problem that if the illumination unevenness is reduced according to the infrared light, the light amount becomes insufficient with visible light, and if the illumination unevenness is reduced according to the visible light, the illumination unevenness is noticeable with the infrared light. .

[0004] It is an object of the present invention to provide a fundus camera having mydriatic and non-mydriatic functions and capable of switching between these functions by simple means.

[0005]

In order to solve this problem, the present invention irradiates light from an observation light source to the fundus of an eye to be inspected via an illumination system, and converts reflected light from the fundus into an image forming optical system. In a fundus camera that forms an image through a system and observes the fundus, means for switching the emission wavelength of the observation light source, means for switching the diffusion characteristics of the observation light source, and a mydriatic function and a non-mydriatic function for the fundus camera Means for switching the light emission wavelength and the diffusion characteristic of the observation light source according to the switching between the mydriatic function and the non-mydriatic function.

According to such a configuration, the emission wavelength and the diffusion characteristic of the observation light source can be switched according to the switching between the mydriatic function and the non-mydriatic function. Even when switching to any of the pupil-type functions, favorable fundus observation without illumination unevenness becomes possible.

The diffusion characteristics of the observation light source when switched to the mydriatic function are as follows. The diffusion characteristics of the optical element having the first diffusion function and the diffusion characteristics of the observation light source when switched to the non-mydriatic function are as follows. It is obtained by arranging an optical element having the first diffusion function and an optical element having the second diffusion function in the optical path of the light source. In such a configuration, the diffusion function of the optical element having the first diffusion function is adjusted to the mydriatic type, and when switching to the non-mydriatic type function, the insufficient diffusion function is replaced by the second diffusion function. The optical element can have the optical element.

Further, in order to switch between the mydriatic function and the non-mydriatic function, it is necessary to switch the emission wavelength of the observation light source between visible light and infrared light. In the present invention, this is realized by using a light source including, for example, visible light and infrared light, and inserting a visible light transmitting filter or an infrared light transmitting filter into the optical path in front of the observation light source. The illumination system for removing flare is switched between a mydriatic illumination system and a non-mydriatic illumination system in accordance with the switching between the two functions.

The optical element having the first diffusion function is realized by, for example, ground glass or a diffusion plate, and the optical element having the second diffusion function is realized by, for example, ground glass or a diffusion plate. When the infrared light transmitting filter is made of glass, the optical element having the second diffusing function can also be realized by processing the surface of the filter with a surface.

The focus detection is switched between visible light and infrared light. Further, the focus detection is switched between visible light and infrared light, and the finder system is switched between the eyepiece and the CCD camera in conjunction with the focus detection.

Further, according to the present invention, when switching to the non-mydriatic function, the emission wavelength of the observation light source is switched to infrared light, and the diffusion characteristic of the central part of the observation light source is different from that of the peripheral part. Can be switched to In this way, even if the fundus camera is switched between the mydriatic and non-mydriatic functions, good fundus observation without illumination unevenness is possible.

In this manner, since both the mydriatic and non-mydriatic functions can be realized by a simple switching operation, a space-saving fundus camera with good usability can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings.

FIG. 1 shows a fundus camera according to the present invention.
A lamp LA, which is a light source for observation that generates visible light including infrared light, is disposed at the center of the mirror M1, and light emitted from this lamp is condensed by a condenser lens L1, an optical element having a first diffusion function. After passing through G1, filter F1, condenser lens L2, reflected by total reflection mirror M2, and then passed through relay lenses L3, L4, reflected by perforated total reflection mirror M3 with a hole at the center, and then passed through objective lens L5. The light then enters the fundus Er from the pupil Ep of the eye E to be examined. Here, the optical element G1 having the first diffusion function
Is made of a ground glass or a diffusion plate, and is set to have a diffusion function of a degree suitable for reducing illumination unevenness during observation when functioning as a mydriatic type.

The filter F1 passes only visible light. The filter F1 is used when the fundus camera is used as a mydriatic type. When the fundus camera is used as a non-mydriatic type fundus camera, the filter F1 is used only for infrared light. Is replaced by a filter F2 that allows the light to pass through and an optical element G2 having a second diffusion function. Here, the optical element G2 having the second diffusion function
Is similarly made of ground glass or diffuser,
The first optical element G1 has a diffusing function to compensate for the insufficient diffusivity of the first optical element G1, and has a characteristic of appropriately diffusing infrared light and reducing illumination unevenness with infrared light.

The reflected light from the fundus Er is received again from the pupil Ep via the objective lens L5, and a perforated total reflection mirror M3 is received.
Passes through the focusing lens L6 and the imaging lens L7 through the hole, and enters the mirror M4. The light reflected by the mirror M4 is reflected by the mirror M5 and observed by the examiner S through the eyepiece L8. The mirror M5 is configured to be able to be removed from the optical path. When the mirror M5 is removed from the optical path, the light beam reflected by the mirror M4 is reflected on the mirror M6 and then formed on the CCD via the lens L9. Imaged.

Further, light sources LED1 and LED2 for focus detection are provided, and light from these light sources passes through a mirror M7, a lens L10, a mirror M8, and a lens L11 between the perforated total reflection mirror M3 and the imaging lens L6. Is incident on the mirror M9 disposed at the position, and a spot image for focusing is formed on the fundus via the perforated total reflection mirror M3 and the lens L5.

In order to photograph a fundus image on the film F, a strobe SR as a photographing light source is disposed between the filter F1 and the lens L2. When photographing the fundus image on the film F, the mirror M4 is removed from the optical path, and the fundus image is guided onto the film F.

In the retinal camera of the present invention, various switching operations are performed so that both functions of the mydriatic retinal camera and the non-mydriatic retinal camera can be performed.

First, the emission wavelength of the light source for illuminating and observing the eye E is switched. In the non-mydriatic type,
The fundus must be illuminated with infrared light, and since the lamp LA contains visible light, it is necessary to cut off the visible light from the lamp LA. Therefore, the filter F1 that passes only visible light is replaced with the infrared transmitting filter F that passes only infrared light.
2 and the optical element G2 having the second diffusion function. That is, when the fundus camera is of a mydriatic type, the filter F1 is inserted into the optical path, and when the fundus camera is of a non-mydriatic type, the optical element G2 having the second diffusion function and the filter F2 are inserted into the optical path. .

Here, the optical element G having the second diffusion function
Reference numeral 2 has a diffusing function that compensates for poor diffusivity of infrared light. That is, the diffusivity of the infrared light is lower than that of the visible light, and the diffusivity of the optical element G1 for the visible light is insufficient, and the illumination unevenness becomes noticeable. Therefore, the optical element G2 is provided with a diffusing function to compensate for the insufficient diffusivity of the optical element G1 for infrared light. The optical element G2 can be realized by a simple optical element such as ground glass or a plastic diffusion plate. When the infrared transmission filter F2 is made of glass, the surface of the filter F2 may be formed as a slick surface to be used as a substitute for the optical element G2.

Next, in order to remove flare, the illumination system lens is switched to lenses L3 and L4 for a mydriatic type and lenses L3 'and L4' for a non-mydriatic type. As a result, switching between the mydriatic illumination system and the non-mydriatic illumination system is performed.

Further, a focus index, ie, a spot for focusing, is radiated to the fundus for focus detection. In the mydriatic type, visible light is used, and in the non-mydriatic type, infrared light is used. The focus index of visible light and the focus index of infrared light are switched according to switching between the mydriatic type and the non-mydriatic type. Therefore, the mirror M7 is inserted into the optical path or detached from the optical path. As the light source for focus detection, the light emitting diode LED1 that emits visible light is used in the mydriatic type, and the infrared light emitting diode LED2 is used in the non-mydriatic type. Therefore, the mirror M7 is used in the mydriatic type. In the non-mydriatic type, the mirror M7 is removed from the optical path. In this way, the light from these light sources is applied to the fundus via the mirrors M8 and M9, and a spot image, which is a focus index of infrared light or visible light, is projected on the fundus.

In the mydriatic type, a fundus image is observed through an eyepiece L8, and a focusing operation is performed. In the non-mydriatic type, the mirror M5 is removed from the optical path, and C
Focus detection is performed via a spot image formed on a CD. In either type, focusing is performed by the examiner S adjusting the focusing lenses L6 and L11 while observing with an eyepiece or while looking at the image formed on the CCD.

In this manner, the switching between the mydriatic type and the non-mydriatic type is performed. However, since all of these switchings must be performed at the same time and must be performed simply and reliably, FIG. As described above, the filter F1 and the optical element having the second diffusion function as shown in the schematic block 12 via the actuator 11 such as a rotary solenoid which is turned on / off by the switch 10 for switching between the mydriatic type and the non-mydriatic type. Switching between G2 and filter F2 is performed, and switching between lens systems L3, L4 and L3 ', L4' is performed as shown in block 13, and mirrors are further displayed as shown in blocks 15 and 16. Each of M5 and M7 is inserted into or removed from the optical path. Switching at the time of focus detection is performed by the light emitting diode LED1 as shown in block 14.
And LED 2 are turned on in accordance with the switching of the switch 10.

Next, the operation of the fundus camera configured as described above will be described.

First, when used as a mydriatic type, the switch 10 is used to switch to a mydriatic type. As a result, the actuator 11 operates, and the filter F1, the lens system L
3, L4 and mirrors M5 and M7 are inserted in the optical path, and the visible light emitting diode LED1 is turned on. Fundus Er by filter F1 that allows visible light to pass
Is illuminated with visible light, while a spot image formed by the visible light emitting diode LED1 is observed by the examiner S, and focusing is performed by adjusting the focusing lens L6. In the mydriatic type, it becomes possible to observe or photograph the fundus using the examiner S or the film F. At this time, the visible light from the light source is diffused by the optical element G1 having the first diffusion function to such an extent that the illumination unevenness can be reduced, so that good fundus observation or imaging with less illumination unevenness is guaranteed.

On the other hand, when used as a non-mydriatic type,
When the actuator 11 is turned off, the optical element G2 having the second diffusion function, the infrared transmission filter F2, and the lens systems L3 ', L4' are inserted into the optical path, and the mirrors M5, M5
7 is removed from the optical path. Further, the infrared light emitting diode LED2 is turned on. In any case, the LED that is not used is turned off. The fundus Er is illuminated with infrared light by the filter F2 that passes infrared light,
On the other hand, focusing is performed by a spot image formed on the CCD by the infrared light emitting diode LED2. With the non-mydriatic type, a wide angle of view cannot be obtained as with the mydriatic type, but the burden on the patient can be reduced to enable fundus observation and imaging. Further, it is also conceivable to use a method in which an image is taken with a non-mydriatic type, and if there is any doubt, a mydriatic agent is instilled to perform imaging with the mydriatic type. In any case, when used as a non-mydriatic type, since the optical element G2 having the second diffusion function is inserted, the optical element G1 compensates for the insufficient diffusivity of the optical element G1 for infrared light. A diffusion function is obtained, and good fundus observation and imaging with little illumination unevenness are guaranteed even for infrared light.

In the embodiment described above, the diffusion characteristic of the observation light source is switched according to the switching between the mydriatic type and the non-mydriatic type, so that the function is improved as compared with the case where the diffusion characteristic is fixed. Can be done. However, as shown in FIG. 3, in the central portion (near the optical axis), the illuminating light 20 is perpendicularly incident on the optical element G1 or G2 having a diffusing function, so that the illumination light 20 is more easily transmitted than in the peripheral portion. Is particularly remarkable in infrared light. Therefore, the center (near the optical axis)
In such a case, there is a problem that sufficient diffusivity cannot be obtained and the central portion becomes too bright. For this reason, when the central portion is adjusted to the optimum light amount, there is a problem that the periphery becomes too dark this time.

In order to improve this point, an optical element having a diffusing function whose central portion has a higher diffusivity than the peripheral portion has an optical element G1 having a first diffusing function and an optical element G2 having a second diffusing function. An element is used.

FIGS. 4 and 5 show examples of optical elements having such a diffusion characteristic. In each of the drawings, the optical element 30 having a diffusion function is realized by, for example, ground glass or a diffusion plate, and is formed so that the central portion has a better diffusivity than the peripheral portion. For example, when the optical element 30 having the diffusion function is formed of ground glass, as shown in FIG. 4, the diffusion surface 30a at the center of the optical element 30 is replaced with the peripheral surface 30b at the peripheral portion. It can be realized by making it rougher. Alternatively, as shown in the example of FIG. 5, the optical element 30 may be realized by forming one surface of the optical element 30 as a uniform sliding surface 30b and forming only the center of the opposite surface on the similar sliding surface 30b.

In the case where a diffusion plate is used, the above-described diffusion characteristics can also be realized by hollowing out the center of the diffusion plate and fitting a high-diffusion diffusion plate into that portion.

The optical element 30 having such a diffusion characteristic
Is used for the optical element G1 having the first diffusion function and the optical element G2 having the second diffusion function, so that the above-described problem can be solved.

The optical element G2 having the second diffusion function
In the case where the infrared light transmitting filter is made of glass, it can also be realized by subjecting the surface of the filter to a surface grinding as shown in FIG. 4 or FIG.

As described above, by making the diffusion characteristics of the optical element having the diffusion function different between the central part and the peripheral part, the diffusion function that compensates for the insufficient diffusivity of the optical element G1 for infrared light is provided. Thus, a diffusing function for compensating for the difference in diffusivity generated between the central portion and the peripheral portion is obtained, and excellent fundus observation and photographing with less illumination unevenness are guaranteed even for infrared light.

[0036]

As described above, according to the present invention, the emission wavelength and the diffusion characteristic of the observation light source can be switched in accordance with the switching between the mydriatic function and the non-mydriatic function, so that the fundus camera can be used in the mydriatic type. Even if the function is switched to the non-mydriatic function or the non-mydriatic function, good fundus observation without illumination unevenness becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a schematic configuration of a fundus camera of the present invention.

FIG. 2 is a block diagram showing a configuration for switching between mydriatic and non-mydriatic functions.

FIG. 3 is an explanatory diagram illustrating a difference in diffusivity between a central portion and a peripheral portion of infrared light of an optical element having a diffusing function.

FIG. 4 is a configuration diagram showing an optical element having a diffusion function according to the present invention.

FIG. 5 is a configuration diagram showing another example of an optical element having a diffusion function.

[Explanation of symbols]

 LA lamp F1 Visible light transmitting filter F2 Infrared transmitting filter E Examinee eye S Examiner LED1 Visible light emitting diode LED2 Infrared light emitting diode G1 Optical element having first diffusing function G2 Optical element having second diffusing function 30 Optical element with diffusion function

Claims (10)

[Claims] 1. A fundus camera for irradiating light from an observation light source to a fundus of an eye to be examined via an illumination system and forming an image of reflected light from the fundus via an imaging optical system to observe the fundus. Means for switching the emission wavelength of the observation light source, means for switching the diffusion characteristic of the observation light source, and means for switching the fundus camera between a mydriatic function and a non-mydriatic function. A fundus camera characterized by switching the emission wavelength and diffusion characteristics of an observation light source in accordance with switching of a mold function. 2. A means for switching the illumination system between a mydriatic illumination system and a non-mydriatic illumination system, wherein the illumination system is also mydriatic illumination in response to switching between the mydriatic function and the non-mydriatic function. The fundus camera according to claim 1, wherein the fundus camera is switched between a system and a non-mydriatic illumination system. 3. The diffusion characteristic of the observation light source when switched to the mydriatic function is obtained by changing the optical element having the first diffusion function and the diffusion characteristic of the observation light source when switched to the non-mydriatic function. 3. The fundus camera according to claim 1, wherein the optical element is obtained by arranging an optical element having a first diffusion function and an optical element having a second diffusion function in a light source optical path. 4. The fundus camera according to claim 3, wherein the optical element having the second diffusing function is ground glass. 5. The fundus camera according to claim 3, wherein the optical element having the second diffusion function is a diffusion plate. 6. The light emission wavelength is switched through a glass filter that allows only light from an observation light source to pass infrared light when switched to a non-mydriatic function, and has the second diffusion function. 4. The fundus camera according to claim 3, wherein the optical element is obtained by processing the surface of the filter with a surface. 7. The fundus camera according to claim 1, wherein a diffusion characteristic of the observation light source is different between a central portion and a peripheral portion. 8. The fundus camera according to claim 7, wherein a diffusion characteristic at a central portion of the observation light source is higher than that at a peripheral portion. 9. A fundus camera that irradiates light from an observation light source to a fundus of an eye to be examined via an illumination system and forms an image of reflected light from the fundus through an imaging optical system to observe the fundus. Means for switching the emission wavelength of the light source for observation, means for switching the diffusion characteristics of the light source for observation, and means for switching the fundus camera between the mydriatic function and the non-mydriatic function. A fundus camera, wherein the emission wavelength of the observation light source is switched to infrared light, and the diffusion characteristic of the central part of the observation light source is switched to a characteristic different from that of the peripheral part. 10. The fundus camera according to claim 9, wherein a diffusion characteristic of a central portion of the observation light source is switched to a higher diffusion characteristic than a peripheral portion.