JP3815527B2 - Fundus camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fundus camera, and more particularly, to a fundus camera in which a mydriatic fundus camera and a non-mydriatic fundus camera are integrated and the functions of both fundus cameras can be switched.
[0002]
[Prior art]
Generally, a mydriatic type fundus camera and a non-mydriatic type fundus camera are known as cameras for imaging a fundus image by forming an image of reflected light from the fundus illuminated by light from a light source. The mydriatic fundus camera mainly uses a light source of visible light, can capture a wide angle of view, and has a tilt mechanism of the camera itself, so that the entire fundus can be photographed. A drawback of this mydriatic retinal camera is that it is necessary to dilate the eye to be measured, which places a great burden on the subject. On the other hand, the non-mydriatic fundus camera uses infrared light as the light source, so it is not necessary to make the subject's eye mydriatic, but the angle of view is not as wide as the mydriatic and can be taken around the fundus macular area. Focusing is also performed by projecting an infrared light focus index onto the fundus without using visible light. Also, by placing ground glass in the observation light source part, or making one surface of the condenser lens used in the observation light source part into a ground surface, uneven illumination during observation (such as due to the image of the lamp filament, Attempts have been made to reduce (such as the central part being too bright).
[0003]
[Problems to be solved by the invention]
In the conventional fundus camera, each of the above functions is realized as a mydriatic fundus camera or a non-mydriatic fundus camera, and visible light and infrared light are respectively configured as dedicated observation light sources during observation. Therefore, 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 with one unit, infrared light is less diffusive. When the uneven illumination is reduced, the amount of light is insufficient with visible light, and when the uneven illumination is reduced in accordance with the visible light, the uneven illumination with infrared light is noticeable.
[0004]
An object of the present invention is to provide a fundus camera having a mydriatic type and a non-mydriatic type function and capable of switching both functions by simple means.
[0005]
[Means for Solving the Problems]
In order to solve this problem, the present invention irradiates the fundus of the subject's eye with light from an observation light source through an illumination system, and forms an image of reflected light from the fundus through an imaging optical system. In the fundus camera to be observed, there are provided 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 to a mydriatic function and a non-mydriatic function. A configuration is adopted in which the light emission wavelength and diffusion characteristics of the observation light source are switched according to switching between the pupil type function and the non-mydriatic type function.
[0006]
According to such a configuration, the light emission wavelength and the diffusion characteristic of the observation light source can be switched according to switching between the mydriatic function and the non-mydriatic function, so the fundus camera can be switched between the mydriatic function and the non-mydriatic function. Even if it switches to any of these, favorable fundus observation without illumination unevenness is attained.
[0007]
The diffusion characteristic of the observation light source when switched to the mydriatic function is the optical element having the first diffusion function, and the diffusion characteristic of the observation light source when switched to the non-mydriatic function is the first It is obtained by arranging an optical element having a diffusion function and an optical element having a second diffusion function in the light source optical path. In such a configuration, when the diffusion function of the optical element having the first diffusion function is matched with the mydriatic type and switched to the non-mydriatic function, the insufficient diffusion function is changed to the second diffusion function. The optical element can be provided.
[0008]
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, for example, by using a light source including visible light and infrared light, and inserting a visible light transmission filter or an infrared light transmission filter in the optical path in front of the observation light source. Also, the illumination system for removing flare is switched between a mydriatic illumination system and a non-mydriatic illumination system in accordance with the switching of both functions.
[0009]
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 also realized by, for example, the ground glass or the diffusion plate. When the infrared light transmission 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 slit surface.
[0010]
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 viewfinder system is switched between the eyepiece lens and the CCD camera in conjunction therewith.
[0011]
In the present invention, when the non-mydriatic function is switched, the emission wavelength of the observation light source is switched to infrared light, and the diffusion characteristic at the center of the observation light source is switched to a characteristic different from that of the peripheral part. . In this way, good fundus observation with no illumination unevenness can be achieved regardless of whether the fundus camera is switched to the mydriatic or non-mydriatic function.
[0012]
In this way, both mydriatic and non-mydriatic functions can be realized by a simple switching operation, so that a space-saving fundus camera with good usability can be obtained.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail according to embodiments shown in the drawings.
[0014]
FIG. 1 shows a fundus camera according to the present invention. A lamp LA, which is an observation light source that generates visible light including infrared light, is disposed at the center of the mirror M1, and the light emitted from this lamp is a condenser lens L1 and an optical element having a first diffusion function. G1, the filter F1, and the condenser lens L2 are reflected by the total reflection mirror M2, then the relay lenses L3 and L4 are reflected by the holed total reflection mirror M3 having a hole in the center, and then the objective lens L5 is passed. Then, the light enters the fundus Er from the pupil Ep of the eye E. Here, the optical element G1 having the first diffusing function is composed of a ground glass or a diffusing plate so as to have a diffusing function suitable for reducing uneven illumination during observation when functioning as a mydriatic type. Set it.
[0015]
The filter F1 is a filter that allows only visible light to pass. When the fundus camera is used as a mydriatic type, the filter F1 allows only infrared light to pass when used as a non-mydriatic type fundus camera. It is replaced with an optical element G2 having a filter F2 and a second diffusion function. Here, the optical element G2 having the second diffusing function is similarly composed of a ground glass or a diffusing plate, and has a diffusing function that compensates for the insufficient diffusibility of the first optical element G1. It has the characteristics that light can be diffused moderately and uneven illumination with infrared light can be reduced.
[0016]
The reflected light from the fundus Er is received again from the pupil Ep through the objective lens L5, passes through the focusing lens L6 and the imaging lens L7 through the hole of the perforated total reflection mirror M3, 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 lens L8. The mirror M5 is configured 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 CCD via the lens L9 after being reflected by the mirror M6. Imaged.
[0017]
Further, light sources LED1 and LED2 for focus detection are provided, and light from these light sources is disposed between the perforated total reflection mirror M3 and the imaging lens L6 via the mirror M7, the lens L10, the mirror M8, and the lens L11. Is incident on the mirror M9, and a spot image for focusing is formed on the fundus via the perforated total reflection mirror M3 and the lens L5.
[0018]
In addition, in order to photograph a fundus image on the film F, a strobe SR, which is a photographing light source, is disposed between the filter F1 and the lens L2. When a fundus image is taken on the film F, the mirror M4 is removed from the optical path so that the fundus image is guided onto the film F.
[0019]
In the fundus camera of the present invention, various switching operations are performed so that the functions of both the mydriatic fundus camera and the non-mydriatic fundus camera can be performed.
[0020]
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 the visible light from the lamp LA. For this purpose, the filter F1 that passes only visible light is switched to an infrared transmission filter F2 that passes only infrared light and an optical element G2 having a second diffusion function. That is, when the fundus camera is a mydriatic type, the filter F1 is inserted into the optical path, and when it is a non-mydriatic type, the optical element G2 having the second diffusion function and the filter F2 are inserted into the optical path. .
[0021]
Here, the optical element G2 having the second diffusing function has a diffusing function enough to compensate for the poor diffusibility of infrared light. That is, infrared light is less diffusive than visible light, and the diffusivity of the optical element G1 adapted for visible light is insufficient, and illumination unevenness is noticeable. Therefore, the optical element G2 is provided with a diffusion function that compensates for the insufficient diffusibility of the optical element G1 with respect to infrared light. The optical element G2 can be realized by a simple optical element such as ground glass or a plastic diffusion plate. In addition, when the infrared transmission filter F2 is glassy, the optical element G2 can be substituted by making the surface of the filter F2 a slit surface.
[0022]
Next, in order to remove the flare, the illumination system lens is switched to the mydriatic lenses L3 and L4 and the non-mydriatic lenses L3 ′ and L4 ′. Thereby, switching between the mydriatic illumination system and the non-mydriatic illumination system is performed.
[0023]
Further, for focus detection, a focus index, that is, a spot for focusing, is irradiated on the fundus. Visible light is used for the mydriatic type, and infrared light is used for the non-mydriatic type. The focus index for visible light and the focus index for infrared light are switched according to switching between the type and the non-mydriatic type. For this reason, the mirror M7 is inserted into or removed from the optical path. As the light source for focus detection, the light emitting diode LED 1 that emits visible light is used in the mydriatic type, and the infrared light emitting diode LED 2 is used in the non-mydriatic type. On the other hand, in the non-mydriatic type, the mirror M7 is removed from the optical path. In this way, light from these light sources is irradiated onto the fundus via the mirrors M8 and M9, and spot images, which are focus indexes of infrared light or visible light, are respectively projected onto the fundus.
[0024]
In the mydriatic type, the fundus image is observed through the eyepiece lens L8, and the focusing operation is performed thereby. In the non-mydriatic type, the mirror M5 is removed from the optical path, and focus detection is performed via a spot image formed on the CCD. In any type, focusing is performed by the examiner S adjusting the focusing lenses L6 and L11 while observing with an eyepiece lens or viewing an image formed on the CCD.
[0025]
In this way, 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 it is necessary to easily and surely perform the switching, as illustrated in FIG. The filter F1, the optical element G2 having the second diffusing function, and the filter as shown in the schematic block 12 through the actuator 11 such as a rotary solenoid that is turned on and off by the switch 10 for switching between the mydriatic type and the non-mydriatic type F2 is switched, and the lens systems L3, L4 and L3 ′, L4 ′ are switched as shown in block 13, and mirrors M5, M7 are further switched as shown in blocks 15, 16. Are inserted into or removed from the optical path. Further, the switching at the time of focus detection is performed by turning on either one of the light emitting diodes LED1 and LED2 in accordance with the switching of the switch 10, as illustrated in the block 14.
[0026]
Next, the operation of the fundus camera configured as described above will be described.
[0027]
First, when using as a mydriatic type, the switch 10 switches to the mydriatic type. As a result, the actuator 11 operates to insert the filter F1, the lens systems L3 and L4, and the mirrors M5 and M7 into the optical path, and the visible light emitting diode LED1 is turned on. The fundus Er is illuminated with visible light by the filter F1 that allows visible light to pass, while the spot image formed by the visible light emitting diode LED1 is observed by the examiner S to adjust the focus lens L6. Matching is done. In the mydriatic type, fundus observation or photographing by the examiner S or the film F becomes possible. At this time, the visible light from the light source is diffused by the optical element G1 having the first diffusing function to such an extent that illumination unevenness can be reduced, so that good fundus observation or photographing with little illumination unevenness is guaranteed.
[0028]
On the other hand, when used as a non-mydriatic type, the actuator 11 is turned off, and the optical element G2 having the second diffusion function, the infrared transmission filter F2, and the lens systems L3 ′ and L4 ′ are inserted into the optical path. Then, the mirrors M5 and M7 are detached from the optical path. In addition, the infrared light emitting diode LED2 is turned on. In either case, the LED that is not used is turned off. The fundus Er is illuminated with infrared light by the filter F2 that allows infrared light to pass through, while focusing is performed by a spot image formed on the CCD by the infrared light emitting diode LED2. In the non-mydriatic type, a wide angle of view cannot be obtained unlike the mydriatic type, but the fundus observation and photographing can be performed while reducing the burden on the patient. Another possible method is to take a non-mydriatic type, and if there is a suspicion, apply a mydriatic agent and shoot with a mydriatic type. In any case, when used as a non-mydriatic type, the optical element G2 having the second diffusing function is inserted, so that the diffusibility of the optical element G1 with respect to infrared light is compensated. A diffusion function is obtained, and good fundus observation and photographing with little illumination unevenness is ensured even for infrared light.
[0029]
In the embodiment as described above, the diffusion characteristic of the observation light source is switched according to switching between the mydriatic type and the non-mydriatic type, so that the function can be improved as compared with the case where the diffusion characteristic is fixed. it can. However, as shown in FIG. 3, in the central portion (near the optical axis), the illumination light 20 enters the optical element G1 or G2 having a diffusing function perpendicularly, so that it is more easily transmitted than the peripheral portion. Is particularly noticeable in infrared light. Therefore, there arises a problem that sufficient diffusibility cannot be obtained in the central portion (near the optical axis) and the central portion becomes too bright. For this reason, if the central portion is adjusted to the optimum light amount, there arises a problem that the periphery becomes too dark this time.
[0030]
In order to improve this point, an optical element having a diffusion function with a higher diffusivity at the center than at the periphery is used for the optical element G1 having the first diffusion function and the optical element G2 having the second diffusion function. Is done.
[0031]
Examples of optical elements having such diffusion characteristics are shown in FIGS. In each figure, the optical element 30 having a diffusing function is realized by, for example, ground glass or a diffusing plate, and is formed so that the diffusibility of the central part is better than that of the peripheral part. For example, when the optical element 30 having a diffusing function is formed of ground glass, such a diffusion characteristic is obtained by changing the central surface 30a of the optical element 30 to the peripheral surface 30b as shown in FIG. It can be realized by making it rougher. Alternatively, as shown in the example of FIG. 5, one surface of the optical element 30 may be a uniform groove surface 30b, and only the central portion of the opposite surface may be formed on the similar groove surface 30b.
[0032]
In addition, when the diffusion plate is used, the diffusion characteristics described above can also be realized by cutting through the central portion of the diffusion plate and fitting a highly diffusible diffusion plate into that portion.
[0033]
By using the optical element 30 having such diffusion characteristics for the optical element G1 having the first diffusion function and the optical element G2 having the second diffusion function, the above-described problems can be solved.
[0034]
When the infrared light transmission filter is made of glass, the optical element G2 having the second diffusing function is subjected to a slit surface processing as shown in FIG. 4 or FIG. 5 directly on the surface of the filter. Can also be realized.
[0035]
Thus, by making the diffusion characteristics of the optical element having the diffusion function different between the central portion and the peripheral portion, the diffusion function that compensates for the insufficient diffusibility of the optical element G1 with respect to infrared light, and the center A diffusion function that compensates for the difference in diffusibility produced in the peripheral part and the peripheral part can be obtained, and good fundus observation and photographing with little illumination unevenness can be guaranteed even for infrared light.
[0036]
【The invention's effect】
As described above, in the present invention, since 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, the fundus camera can be switched between the mydriatic function and the non-mydriatic function. Good fundus observation without illumination unevenness can be achieved by switching to any of the mold functions.
[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 a mydriatic function and a non-mydriatic function.
FIG. 3 is an explanatory diagram for explaining a difference in diffusibility between the central portion and the peripheral portion of infrared light of an optical element having a diffusing function.
FIG. 4 is a configuration diagram illustrating 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 Eye to be examined S Examiner LED1 Visible light emitting diode LED2 Infrared light emitting diode G1 Optical element G2 having a first diffusing function Optical element 30 having a second diffusing function Optical element with diffusion function

Claims (10)

In a fundus camera that irradiates the fundus of a subject's eye with light from an observation light source through an illumination system, forms an image of reflected light from the fundus through an imaging optical 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;
A means for switching the fundus camera to a mydriatic function and a non-mydriatic function is provided,
A fundus camera characterized by switching a light emission wavelength and a diffusion characteristic of an observation light source in accordance with switching between the mydriatic function and the non-mydriatic function. Means for switching the illumination system between a mydriatic illumination system and a non-mydriatic illumination system is provided, and the illumination system is also a mydriatic illumination system and a non-mydriatic according to the switching between the mydriatic function and the non-mydriatic function. The fundus camera according to claim 1, wherein the fundus camera is switched to a type illumination system. The diffusion characteristic of the observation light source when switching to the mydriatic function is the optical element having the first diffusion function, and the diffusion characteristic of the observation light source when switching to the non-mydriatic function is the first 3. The fundus camera according to claim 1, wherein the fundus camera is obtained by disposing an optical element having a diffusion function and an optical element having a second diffusion function in the light source optical path. The fundus camera according to claim 3, wherein the optical element having the second diffusing function is ground glass. The fundus camera according to claim 3, wherein the optical element having the second diffusion function is a diffusion plate. When switched to the non-mydriatic function, the emission wavelength is switched through a glass filter that allows only the infrared light to pass through the light from the observation light source, and the optical element having the second diffusing function is the filter. The fundus camera according to claim 3, wherein the surface of the fundus is a surface-finished surface. The fundus camera according to any one of claims 1 to 6, wherein a diffusion characteristic of the observation light source is different between a central portion and a peripheral portion. The fundus camera according to claim 7, wherein a diffusion characteristic of a central portion of the observation light source is higher than that of a peripheral portion. In a fundus camera that irradiates the fundus of a subject's eye with light from an observation light source through an illumination system, forms an image of reflected light from the fundus through an imaging optical 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;
A means for switching the fundus camera to a mydriatic function and a non-mydriatic function is provided,
When the non-mydriatic function is switched, 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 the peripheral part. camera. The fundus camera according to claim 9, wherein a diffusion characteristic at a central portion of the observation light source is switched to a higher one than a peripheral portion.

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