JPH08317905A - Eyeground camera - Google Patents

Abstract

PURPOSE: To form an eyeground image without being out of focus even near the border of a diopter adjusting region. CONSTITUTION: A light beam L2, which is emitted from an index projecting light source 23 and reflected on the eyeground, reaches an photoelectric element 24 through a diopter detecting optical system for the eye examination. Then, the absolute value of diopter of an eye E to be examined from the image forming position of the light beam L2. Meanwhile, in the optical system for the observational photography, the position of a focus lens 4 is detected by a focal lens detecting means 8. Then, the difference between the diopter of the eye E to be examined and the diopter detected in the optical system for the observational photography is calculated by an operational means 25. And then, the focal state in the eyeground camera optical system is phasedly displayed with the eyeground in a displaying means 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera used in an ophthalmology clinic or the like.

[0002]

2. Description of the Related Art Conventionally, with an ophthalmologic apparatus for observing and photographing the fundus, it is very difficult to focus due to the low reflectance and poor contrast of the fundus, and in order to easily enable focusing, A method of introducing a projection optical system having the above into the illumination optical system of the fundus camera to project a target onto the fundus and observing the projected image with the observation optical system to perform focusing is disclosed by the applicant of the present application. It has been proposed in Japanese Patent No. 13294.

This device divides a projection light beam of an optotype, which is optically arranged substantially at a conjugate position with the fundus of the eye to be inspected, and forms an image on the fundus by splitting it by a split prism or the like, and observes the deviation of the optotype image. Focus adjustment is performed by mechanically interlocking the target and the focus lens in the illumination optical system to make the target and the observation and photographing image plane conjugate with the fundus oculi.

[0004]

However, in the mechanical interlocking mechanism of the optotype projection optical system and the focus lens of the observation / photographing optical system as in the above-mentioned conventional example, the visual observation to the fundus is made at the end of the diopter adjustment range. An optical misalignment between the target and the image plane for observation and shooting occurs, and when the target image is observed and photographed, it becomes a poorly focused fundus image, and the mechanical interlocking mechanism becomes complicated, and the There is a problem that the adjustment becomes delicate and complicated.

A first object of the present invention is to solve the above-mentioned problems and to provide a fundus camera which can easily obtain a fundus image free from focus even at the end of the diopter adjustment range.

A second object of the present invention is to provide a fundus camera in which the number of movable parts is reduced and the mechanical interlocking mechanism is eliminated, thereby simplifying the device and simplifying adjustment during assembly.

A third object of the present invention is to provide a fundus camera which enables accurate autofocus operation without complicating the apparatus.

[0008]

To achieve the above object, a fundus camera according to a first aspect of the present invention is an illumination optical system for illuminating a fundus of an eye to be inspected and an observation and photographing optical for observing and photographing the fundus of the eye to be inspected. System, diopter adjustment means for adjusting the diopter of the observation and photographing optical system, eye diopter detection means for detecting the diopter of the subject's eye, and optical system vision for detecting diopter of the observation and photographing optical system. And a display unit for displaying information from the eye diopter detection unit and information from the optical system diopter detection unit.

A fundus camera according to a second aspect of the present invention is an illumination optical system for illuminating a fundus of an eye to be inspected, an observation and photographing optical system for observing and photographing the fundus of the eye to be examined, and a vision for adjusting diopter of the observation and photographing optical system. A diopter adjusting means and an eye diopter detecting means for detecting diopter of the eye, and a controlling means for controlling the diopter adjusting means so that the diopter of the eye and the diopter of the observation and photographing optical system coincide with each other. The test eye diopter detection means projects a target for detecting the diopter of the test eye onto the test eye via the diopter adjustment means.

[0010]

The fundus camera of the first invention having the above-mentioned structure is
The illumination optical system illuminates the fundus of the eye to be inspected, and the reflected image from the fundus of the eye is observed and photographed by the observation and photographing optical system. The diopter of the observation and photographing optical system is adjusted by the diopter adjusting device with respect to the diopter of the subject's eye detected by the diopter detecting device, and the diopter information is displayed on the display device.

In the fundus camera of the second aspect of the invention, the diopter adjusting means is controlled by the control means so that the diopter of the eye to be detected detected by the diopter detecting means of the eye is matched with the diopter of the observation and photographing optical system. A target for detecting the diopter of the eye to be inspected is projected onto the eye to be inspected, the eye to be inspected is illuminated by the illumination optical system, and the reflection image from the fundus is observed and photographed by the observation and photographing optical system.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 shows the configuration of a mydriasis type fundus camera of the first embodiment, in which an objective lens 1 is arranged in front of an eye E to be inspected, and a perforated mirror 2 and an image are taken on an optical axis O1 behind the objective lens 1. A diaphragm 3, a focus lens 4 which is a diopter adjusting means, a photographing lens 5, a switching mirror 6, and a photographing image plane 7 are sequentially arranged to form an observation and photographing optical system. Here, the focus lens 4 is provided with a focus lens detection means 8 such as a potentiometer, a rotary encoder, a slit and a photocoupler that can detect the position of the focus lens 4 on the optical axis O1.

A mirror 9 is arranged in the reflection direction of the switching mirror 6, and the observation field stop 1 is arranged in the reflection direction of the mirror 9.
0, a field lens 11, and an eyepiece lens 12 are sequentially arranged, and an LED for displaying information regarding the diopter of the eye E and the diopter of the observation and photographing optical system in the observation visual field is used for the observation visual field diaphragm 10. Display means 1 such as a level meter
3 is provided.

On the optical axis O2 in the incident direction of the perforated mirror 2, a relay lens 14, a dichroic mirror 15 that transmits visible light and reflects infrared light, a relay lens 16, and an anterior segment of the eye E to be examined are conjugated. Ring slit 1 placed in position
7. The light sources for observation and photography 18 are sequentially arranged to form an illumination optical system.

On the optical axis O3 in the incident direction of the dichroic mirror 15, the lens 19 and the anterior ocular segment of the subject's eye E are placed in a conjugate position, and two openings 20a, 20 as shown in FIG.
a two-hole aperture plate 20 having b
An off-axis mirror 21 is arranged behind the opening 20b located below the optical axis O3 of the. Further, on the upper side of the optical axis O3 behind it, a diopter detection optotype plate 22 having a slit-shaped opening placed in a plane substantially conjugate with the fundus of the eye E having a diopter of 0 diopters, The diopter detection target plate 22 is attached to the eye E to be inspected.
A target light source 23 such as a laser diode or an LED that emits near-infrared light for projection onto the fundus of the eye is arranged.

A photoelectric element 24 such as a line sensor or an area sensor is arranged at an in-plane position almost conjugate with the fundus of the eye E to be inspected having a diopter of 0 diopter in the reflection direction of the off-axis mirror 21.
An optical diopter detection optical system for the eye to be inspected is formed by these.
The outputs of the photoelectric element 24 and the focus lens detector 8 are connected to the calculator 25, and the output of the calculator 25 is connected to the display 13.

The light beam emitted from the observation / photographing light source 18 passes through the ring slit 17, is reflected by the perforated mirror 2 through the relay lens 16, the dichroic mirror 15, and the relay lens 14, and is then examined by the objective lens 1 through the eye E. The fundus of the eye. The light reflected from the fundus of the eye E to be examined is
The objective lens 1, the hole portion of the perforated mirror 2, the photographing diaphragm 3, the focus lens 4, the photographing lens 5, the switching mirror 6, the mirror 9, the observation field diaphragm 10, the field lens 11, and the eyepiece lens 12 reach the examiner. The fundus can be observed through the lens 12.

Further, on the display means 13 provided in the observation field stop 10, information about the diopter of the eye E and the diopter of the observation and photographing optical system is displayed together with the fundus image of the eye E, and the examiner displays this information. While observing the fundus image, the focus lens 4 is moved along the optical axis O1 using a focus knob or the like (not shown) to adjust the focus. Then, at the time of shooting, the switching mirror 6 jumps up to the position of the dotted line in the figure, and the light flux from the fundus of the eye is guided to the shooting image plane 7.

A light beam L1 shown by a solid line emitted from a target light source 23 for projecting a target disposed off the optical axis O3 in the reflection direction of the dichroic mirror 15 is an opening portion of the target plate 22 and a two-hole diaphragm plate 20. Through the opening 20a of the lens 20, the dichroic mirror 15, the relay lens 14, the perforated mirror 2, and the objective lens 1 to reach the fundus of the eye E to be inspected.

The light flux L2 reflected from the fundus of the light flux L1 returns to the optical path and returns to the objective lens 1, the perforated mirror 2, the relay lens 14, the dichroic mirror 15, the lens 1.
After passing through the aperture 20b of the two-hole aperture plate 20, the light is reflected by the off-axis mirror 21 to reach the photoelectric element 24, and the photoelectric element 24 outputs a detection signal to the arithmetic means 25.

Further, the detection signal of the position on the optical axis O1 of the focus lens 4 is inputted from the focus lens detection means 8 to the calculation means 25, and the diopter of the observation and photographing optical system can be known. The diopter adjusting means is not limited to the focus lens 4 that moves on the optical axis O1, but may be a variable focus lens whose focal length can be freely changed. In this case, observation shooting from the focal length of the variable focus lens is possible. It is possible to know the diopter of the optical system.

Further, the reflected light flux L2 from the fundus of the eye E to be inspected
Is determined by the diopter of the eye E as shown in FIG.
Since the emission angle is determined and the height from the optical axis O1 that passes on the plane P1 optically conjugate with the photoelectric element 24 is different, the position when reaching the photoelectric element 24 is unique depending on the diopter of the eye E to be examined. To be decided. Therefore, the reflected light flux on the photoelectric element 24
The absolute value of the diopter of the eye E can be known by detecting the position of L2.

Since the position of the focus lens 4 on the optical axis O1 is adjusted so that the photographic image plane 7 and the fundus of the eye E to be examined are optically conjugate, the optical axis O1 of the focus lens 4 is adjusted.
By detecting the upper position, what is the diopter of the photographing image plane 7 with respect to the optical system of the fundus camera is conjugate with the fundus of the eye E to be inspected having a diopter, that is, what is the diopter of the observation photographing optical system? You can see if it is diopter.

Further, the calculating means 25 calculates the amount of deviation between the diopter of the eye E and the diopter of the observation / photographing optical system from the output of the photoelectric element 24 and the output of the focus lens detecting means 8, and FIG.
As shown in, the focus state of the fundus camera is displayed stepwise by a symbol on the display means 13 provided in the observation visual field of the eyepiece lens 12. In this way, by displaying the focus state stepwise, the examiner can focus on a desired fine portion other than the retina to be observed and photographed, for example, the depth direction of the vitreous membrane, the optic disc, or the like. Note that, in FIG. 4, the amount of deviation between the diopter of the eye E and the dioptric power of the observation / photographing optical system is displayed on the display unit 13, but as shown in FIG. Information such as the absolute value of the diopter may be displayed.

As described above, in the present embodiment, the optotype projected on the fundus and the focus lens 4 are mechanically interlocked with each other without providing the movable portion for projecting the optotype on the fundus in the illumination optical system. Since there is no need to move the device, the adjustment during assembly can be simplified without complicating the device, and a fundus image free of focus even at the end of the diopter adjustment range can be obtained. The examiner can easily adjust the focus of the fundus camera by observing the display state of the display unit 13 while observing the fundus of the eye E to be inspected.

In this embodiment, the mydriasis type fundus camera has been described, but the present invention can be similarly applied to the non-mydriasis type fundus camera, and the non-mydriasis type fundus camera has a television monitor. Therefore, it is not necessary to provide a dedicated display unit for displaying information from the diopter detection unit of the eye E and information from the diopter detection unit of the observation and photographing optical system, and the same effect can be obtained without increasing the cost. Obtainable.

FIG. 6 is a block diagram of the non-mydriasis type fundus camera of the second embodiment, in which an objective lens 30 is arranged in front of the eye E to be inspected, and on the optical axis O4 behind the objective lens 30, A perforated mirror 31, a photographing diaphragm 32, a focus lens 33 which is a diopter adjusting means, a photographing lens 34, a switching mirror 35,
The photographic image planes 36 are sequentially arranged. Here, the focus lens 33 is attached to a focus lens position detection drive means 37 for controlling the position on the optical axis O4, and the position detection drive means 37 is an optical axis of the focus lens 33.
It is composed of focus lens position detecting means such as a potentiometer for detecting the position on O4, and focus lens driving means such as a motor for driving the focus lens 33.

Further, in the reflection direction of the switching mirror 35,
A dichroic mirror 38 that transmits near-infrared light in the vicinity of 790 nm, an optotype plate 39 having a slit-shaped opening that is optically conjugate with the photographic image plane 36, a collimator lens 40, and a diopter detection vision. A target light source 41 for projecting a target, such as a laser diode or an LED, which emits near-infrared light in the vicinity of 790 nm for projecting the target on the fundus of the eye E to be examined is sequentially arranged, and a dichroic mirror 38 is provided with a light source 41 in the reflection direction. A lens 42, a television relay lens 43, and a CCD camera 44 that is optically conjugate with the image plane 36 are arranged.

On the optical axis O5 in the incident direction of the perforated mirror 31, a relay lens 45, 700 to 90 as shown in FIG.
Dichroic mirror 4 that reflects infrared light near 0 nm
6, a relay lens 47, a ring slit 48 placed at a conjugate position with the anterior segment of the eye E, and a mirror 49 are arranged,
In the reflection direction of the mirror 49, a condenser lens 50, a photographing light source 51 such as a strobe tube, a condenser lens 52, and FIG.
An infrared filter 53 that cuts visible light and near-infrared light and an observation light source 54 such as a halogen lamp are sequentially arranged as shown in FIG.

Further, on the optical axis O6 in the reflecting direction of the dichroic mirror 46, the lens 55 and the two openings 56 as shown in FIG. 9 placed at the conjugate position with the anterior segment of the eye E to be examined.
a two-hole diaphragm plate 56 having a and 56b, a prism 57 having two elements 57a and 57b as shown in FIG. 10, a line sensor placed substantially in a plane conjugate with the fundus of the eye E to be inspected having a diopter of 0 diopters. Photoelectric elements 58 such as an area sensor and the like are sequentially arranged. The outputs of the photoelectric element 58 and the focus lens position detection drive means 37 are calculated by the calculation means 59.
It is connected to the.

The light flux emitted from the observation light source 54 is wavelength-selected by the infrared filter 53, and the condenser lens 5
2, condenser lens 50, mirror 49, ring slit 48, relay lens 47, dichroic mirror 4
6, the relay lens 45, the perforated mirror 31, and the objective lens 30 are passed through to illuminate the fundus of the eye E to be inspected. Further, the luminous flux emitted from the photographing light source 51, the condenser lens 50,
The fundus of the eye E to be inspected is illuminated via the mirror 49 and the like as in the above-described observation light flux.

The reflected light from the fundus of the eye E to be examined E is an objective lens 30, a perforated mirror 31, a taking lens 32, a focus lens 33, a taking lens 34, a switching mirror 35, a dichroic mirror 38, a field lens 42, and a television relay lens. An image is formed on the CCD camera 44 via 43, and its output is displayed on a television monitor (not shown), and the examiner aligns the eye E and the fundus camera while watching the image on the television monitor. Further, at the time of photographing, the switching mirror 35 jumps up to the dotted line position in the figure, and the light flux from the fundus is guided to the photographing image plane 36.

The light beam L3 shown by the solid line emitted from the visual target projection light source 41 passes through the collimator lens 40 and the opening of the visual target plate 39, passes through the dichroic mirror 38, and is switched to the switching mirror 35, the taking lens 34, and the focus. Lens 3
3, photographing aperture 32, perforated mirror 31, objective lens 30
The image reaches the fundus from the center of the pupil of the eye E through the eye and projects the optotype image on the optotype plate 39. This visual target image becomes clear when the diopter of the eye E and the position of the focus lens 33 on the optical axis O4 match, and the diopter of the eye E and the position of the focus lens 33 on the optical axis O4 become clear. Blurred when misaligned.

The light beam L4 reflected by the fundus of the eye E to be examined, which is the light beam L4, is the objective lens 30 and the perforated mirror 3
1, dichroic mirror 4 via relay lens 45
2 of the lens 55 and the aperture plate 56 with two holes
Is split into two light beams through one opening 56a, 56b,
Each is deflected by the prism 57 and reaches the photoelectric element 58. From the signal received by the photoelectric element 58, the calculating means 5
Reference numeral 9 calculates the diopter of the subject's eye E, and the focus lens position detection drive means 37 drives the optical axis O4 of the focus lens 33.
The upper position is changed and automatically adjusted so that the photographic image plane 36 and the fundus of the eye E to be examined are optically conjugated.

Further, the reflected light flux L4 from the fundus of the eye E to be examined is
As shown in FIG. 11, depending on the diopter of the eye E, the eye E
Since the emission angle is determined and the height from the optical axis O4 that passes through the plane P2 optically conjugate with the photoelectric element 58 is different, the position when the photoelectric element 58 is reached is determined by the diopter of the eye E to be examined. To be decided. Therefore, the reflected light beam split into two
The absolute value of the diopter of the eye E can be known by detecting the distance d between the two spot images on the photoelectric element 58 of L4.

The two-hole diaphragm plate 56 is a diaphragm plate having a plurality of openings, and the reflected light flux L4 from the fundus is divided into a plurality of light spots on the photoelectric element 58. If the distance d between the spot images is detected, it is possible to detect the diopter of the eye E with higher accuracy.

As described above, in this embodiment, the optotype projected on the fundus and the focus lens 33 are mechanically interlocked with each other without providing a movable part for projecting the optotype on the fundus in the illumination optical system. Since there is no need to move the device, the adjustment at the time of assembly can be simplified without complicating the device, and the autofocus operation for controlling the focus lens 33 according to the diopter of the eye E can be performed. It is possible to obtain a fundus image without focus shift even at the end of the range.

Further, since the diopter detecting target is projected on the fundus of the eye E through the focus lens 33, the diopter of the eye E and the position of the focus lens 33 on the optical axis O4 are compared. By reducing the amount of displacement, the two spot images on the photoelectric element 58 become clear, and more accurate focusing becomes possible.

[0039]

As described above, the fundus camera according to the first aspect of the invention does not need to have a movable portion for projecting the optotype on the fundus and mechanically interlocks the optotype with the focus lens. , The device has a simple structure, the assembly and adjustment are easy, and the fundus image without the focus deviation can be displayed even at the end of the diopter adjustment range, and at the same time, the diopter information of the eye to be examined can be displayed stepwise. With this, it is possible to accurately and easily perform focus adjustment even on a detailed observation and imaging site.

The fundus camera according to the second aspect does not require a movable portion for projecting the target onto the fundus and it is not necessary to mechanically interlock the target and the focus lens. Therefore, the device has a simple structure. Assembling and adjustment becomes easy, and by controlling the diopter adjusting means according to the diopter of the eye to be examined, and reducing the amount of deviation between the diopter of the eye to be examined and the diopter of the observation and photographing optical system, It is possible to form a clear spot image on the screen and perform more accurate focus adjustment by the autofocus operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a front view of a two-hole diaphragm plate.

FIG. 3 is an explanatory diagram of a diopter detection light beam.

FIG. 4 is an explanatory diagram of a display screen of display means.

FIG. 5 is an explanatory diagram of a display screen of display means.

FIG. 6 is a configuration diagram of a second embodiment.

FIG. 7 is a graph showing spectral characteristics of dichroic mirrors.

FIG. 8 is a graph showing a spectral characteristic of an infrared filter.

FIG. 9 is a front view of a two-hole aperture plate.

FIG. 10 is a front view of a prism.

FIG. 11 is an explanatory diagram of a diopter detection light beam.

[Explanation of symbols]

 3, 32 Imaging diaphragm 4, 33 Focus lens 7, 36 Photographing image plane 8 Focus lens position detecting means 13 Display means 17, 48 Ring slit 18, 51, 54 Observation and photographing light source 20, 56 Two-hole diaphragm plate 22, 39 View Reference plate 23, 41 Target projection light source 24, 58 Photoelectric element 25, 59 Computing means 37 Focus lens position detection driving means 44 CCD camera 57 Prism

Claims (4)

[Claims] 1. An illumination optical system for illuminating a fundus of an eye to be inspected,
An observation and photographing optical system for observing and photographing the fundus of the eye to be inspected, a diopter adjusting means for adjusting the diopter of the observation and photographing optical system, an eye to be examined diopter detecting means for detecting the diopter of the eye to be inspected, and the observation and photographing. An optical system diopter detecting means for detecting diopter of an optical system, and a display means for displaying information from the eye diopter detecting means and information from the optical system diopter detecting means. Fundus camera. 2. The fundus camera according to claim 1, wherein the inspected eye diopter detection unit projects a target for detecting diopter of the inspected eye onto the inspected eye through the diopter adjustment unit. 3. The fundus camera according to claim 1, wherein the display unit displays the information from the eye diopter detection unit and the information from the optical system diopter detection unit in a stepwise manner. 4. An illumination optical system for illuminating a fundus of an eye to be inspected,
An observation and photographing optical system for observing and photographing the fundus of the eye to be inspected, a diopter adjusting means for adjusting the diopter of the observation and photographing optical system, an eye to be inspected diopter detecting means for detecting the diopter of the eye to be inspected, and an eye to be inspected. And a control means for controlling the diopter adjusting means so that the diopter of the observation and photographing optical system coincides, and the diopter detecting means for the eye to be inspected is an optotype for detecting the diopter of the eye to be inspected. Is projected onto the eye to be inspected through the diopter adjusting means.