JPH1156783A - Ophthalmologic imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable focussing work to be done quickly, by reading the quantity of focussing lens movement corresponding to the quantity of focus shift detected by a focussing condition detecting means from a memory means and driving a focussing lens based thereon. SOLUTION: A difference of voltages showing quantity of light intercepted by each light interceptotr of a two divided light interceptorer is calculated by a difference calculation part 141 to obtain the focussing degree. On the other hand, the voltage difference and the quantity of focussing lens shift to eliminate the difference are stored in a shift quantity memory part 111 making both to correspond. The quantity of focussing lens shift corresponding to the difference calculated by the difference calculation part 141 is read out by a focussing lens drive part 144 from the shift quantity memory part 111. The control signal is transmitted to a focussing lens drive motor 120 so as to drive the focussing lens by the shift quantity. Thus the focussing work ca be quickly done.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a fundus camera and the like.
The present invention relates to an ophthalmologic photographing apparatus for photographing a fundus image of a subject's eye.

[0002]

2. Description of the Related Art Today, an ophthalmologist illuminates the fundus of an eye to be examined and, at the same time, extracts a light beam reflected by the fundus,
A fundus camera for photographing this is widely used. In order to perform appropriate shooting with such a fundus camera,
Prior to photographing, alignment work for setting the relative position between the subject's eye and the fundus camera to an appropriate position, fixation work for fixing the subject's eye in a predetermined direction, and focusing for focusing the image of the fundus of the subject's eye on the photographing means Work needs to be done.

For this reason, the examiner first positions the fundus camera roughly in front of the examiner's eyes while observing the illuminated image of the examinee. Then, an alignment index for performing alignment, a fixation index for performing fixation, and a focus index for performing focusing are projected on the subject. The reflected light of the focusing index and the alignment index is displayed so as to be superimposed on the fundus image, and the examiner adjusts the alignment so that the alignment index is at a predetermined position. Then, the subject is instructed to look at the fixation index and fixation is performed, and then the focusing is performed while observing the focus index. Finally, the photographing release button was pressed, and a desired fundus image was photographed. In recent years, automation of these focusing work, fixation work, and alignment work has been promoted due to a demand for improved operability, and a fundus camera capable of automatically performing each of these works has been proposed and used.

FIG. 7 shows an example of an optical system of a fundus camera that automates a focusing operation among such conventional fundus cameras. In FIG. 7, the fundus camera mainly includes an illumination optical system 200 for illuminating the fundus of the subject's eye 1 and the subject's eye 1.
And a focusing light projection optical system 220 and a focusing light receiving optical system 230 for focusing an image of the fundus of the subject's eye 1 on an imaging CCD 213 to be described later. Have been.

The illumination optical system 200 includes a filter 208 that transmits only invisible light, a lens 209, a mirror 202, a slit 214 that narrows the illumination light to a predetermined range where scattered light does not occur, and an illumination light emitted from the illumination light source 201. Lens 2
15 and the mirror 203, the light is guided to the subject's eye 1, and the reflected light from the subject's eye 1 is
The light is guided to the observation CCD 205 via the lenses 218 and 219 and the half mirror 227. The reflected light received by the observation CCD 205 is displayed as a fundus image of the subject's eye 1 on a monitor (not shown). The photographing optical system 210 guides photographing light emitted from the photographing light source 211 to the subject's eye 1 via the filter 206, the lens 207, and the like, and reflects the reflected light from the subject's eye 1 via the focusing lens 212 to the photographing CCD 213. , And photographing is performed by the photographing CCD 213.

The focusing light projection optical system 220 includes a focusing light source 2
The focused light emitted from 21 is passed through the opening of the focus index 222 to be squeezed into a shape corresponding to the opening, and the narrowed focused light is transmitted from the mirror 226 and the subject's eye 1 to the focusing lens 212. The light is guided to the subject's eye 1 via the half mirror 223 and the stop 216 arranged on the optical axis. The focused light reflected by the subject's eye 1 passes through a half mirror 223, a focusing lens 212 and a movable mirror 204 to a focused light receiving optical system 230 composed of a half mirror 227 and a two-part light receiver 225. Be guided.

Here, the focus index 222 and the photographing CCD
The focusing lens 212 and the focus index 222 are interlocked so as to be conjugate with each other, and the focusing lens 212 is positioned so that the fundus of the subject's eye 1 and the imaging CCD 213 are conjugate with each other. Then, the focus index 22
Numeral 2 is located at the center of the optical axis of the two-segment light receiver 225 in a focused state, that is, in a state where the degree of focusing is appropriate. Therefore, by detecting the degree of focusing of the focusing light on the two-divided light receiver 225 and optimizing the degree of focusing, it is possible to optimize the degree of focusing of the image of the eye to be inspected on the imaging CCD 213. .

The two-divided light receiver 225 is provided with two light receivers 225a and 225b.
25a and 225b are arranged such that the amount of focused light received by each of the light receivers 225a and 225b is equal to each other when the degree of focusing is appropriate. The degree of focusing can be adjusted by moving the focusing lens 212 along its optical axis. Therefore, each light receiver 225a,
The focusing operation is automatically performed by comparing the light amounts of the focusing lights received at 225b and driving the focusing lens 212 until the light amounts become unequal. Such a conventional automatic focusing operation is started when the power of the fundus camera is turned on or when the power of the automatic focusing device is turned on, and is continuously performed until the power is turned off.

[0009]

However, in such a conventional fundus camera, a two-divided light receiver 225 is used.
Since the focusing lens 212 is moved and focused until the light amount difference between the focused lights received by the respective light receivers 225a and 225b disappears, it is necessary to always detect the light amount of the focused light. is there. Therefore, when there are many blinks or the movement is intense, an unnecessary focusing operation based on an erroneous signal is performed, and there is a problem that the focusing operation is not easily completed.

Further, in the conventional fundus camera, the focusing operation is continuously performed. Therefore, even if the in-focus state is obtained once, if the fundus camera moves due to the alignment operation or the like, the operation is repeated. There is a problem that the focusing operation is started, and the in-focus state is not stable even though the focusing operation is once completed.

Further, in the above fundus camera,
Focused light is guided to the subject's eye 1 via a half mirror 223 disposed on the optical axis from the subject's eye 1 to the imaging CCD 213, and reflected light from the subject's eye 1 is also passed through the half mirror 223. Since the light is guided to the two-divided light receiver 225, the focused light and the reflected light from the subject's eye 1 are reflected by the half mirror 22.
3, the light is attenuated when the light passes through No. 3, and there is a problem that the amount of light is insufficient to detect the light receiving operation, or the captured image becomes dark.

Further, in the conventional fundus camera, as shown in FIG. 6, the opening 222a of the focus indicator 222 is simply formed in a rectangular shape having a constant width. Therefore, for example, when the optical axis of the focused light is located at the center of the opening 222a, the light intensity of the focused light passing through the center and received by the light receiver becomes the strongest, The light intensity of the focused light received after passing through was weak. That is, as shown in FIG. 6, a portion of the opening 222a located on the optical axis of the focused light is P3, a portion of the opening 222a separated by a distance L2 in the longitudinal direction of the opening 222a is P4, and the portion P4 is Assuming that the light intensity of the focused light passing therethrough is attenuated by 10% with respect to the light intensity of the focused light passing through the portion P3, as shown in the upper right graph of FIG. Light intensity of light,
The vertical axis is the distance in the longitudinal direction of the opening 222a), the width W
The light intensity K3 of the focused light received after passing through No. 4 is 10% of the light intensity K2 of the focused light received through the width W3.
The luminous intensity of the focused light changes in a curved manner over the entire opening 222a, and as shown in the lower right graph of FIG. Has become smaller. That is, the larger the amount of defocus, the worse the detection accuracy. Therefore, it is necessary to repeat the focusing operation as the amount of defocus increases.

In order to solve such a problem in the conventional fundus camera, according to the present invention, the focusing operation is completed based only on the degree of focusing at the start of the focusing operation, and the focusing operation is rapidly performed. It is an object of the present invention to provide a fundus camera capable of performing the following. Further, the present invention provides a fundus camera that can prevent a once completed focusing operation from being carelessly restarted and stabilize the focusing operation. In addition, the present invention provides a fundus camera which is configured without the need for a half mirror and has a small decrease in the amount of focusing light and photographing light.

[0014]

In order to solve the above-mentioned problems in the conventional fundus camera, the present invention according to the first aspect of the present invention provides a photographing means for photographing an eye to be inspected, and an image of the eye to be inspected on the photographing means. Required for focusing in a fundus camera including a focusing lens that focuses the image and a focusing state detecting unit that detects an amount of defocus from a focused state of the image of the subject's eye in the photographing unit. A moving amount storing means for storing a moving amount of the focusing lens corresponding to the focus shift amount, and a moving amount corresponding to the focus shift amount detected by the focus state detecting means. Focusing lens driving means for reading from the amount storage means and driving the focusing lens based on the read movement amount.

According to a second aspect of the present invention, in the first aspect of the present invention, the in-focus state detecting means receives the measurement light for detecting an amount of defocus from the in-focus state. A light source that irradiates the optometry, a first detection unit and a second detection unit, a two-division light amount detection unit that receives the measurement light reflected by the eye to be inspected, and the first detection unit And a difference calculating means for calculating a difference between the amount of received light detected by the second detecting unit and the amount of received light detected by the second detection unit, and the moving amount storage means is necessary for eliminating the difference. The focusing lens driving unit stores the moving amount of the focusing lens corresponding to the difference, and reads the moving amount corresponding to the difference calculated by the difference calculating unit from the moving amount storage unit. The focusing lens is driven by the read amount of movement. It is.

According to a third aspect of the present invention, there is provided a fundus camera provided with photographing means for photographing the eye to be inspected, and focusing means for focusing the image of the eye to be inspected on the photographing means. Shooting completion determining means for determining whether or not shooting has been completed; focusing completion determining means for determining whether focusing by the focusing means has been completed; and focusing by the focusing completion determining means. When it is determined that the focusing by the means has been completed, the focusing operation of stopping the refocusing operation by the focusing means is stopped until the completion of the photographing by the photographing means is determined by the photographing completion determining means. Means are provided.

According to a fourth aspect of the present invention, there is provided a photographing optical system for photographing an eye to be inspected, and a focusing system for irradiating the eye to be inspected with measuring light for detecting an amount of defocus from a focused state. An ophthalmologic photographing apparatus including a light source for use and a focus state detecting means for detecting a focus shift amount from a focus state of the image of the subject's eye in the photographing means, wherein the light source is separated from an optical axis of the photographing optical system. The focusing light from the focusing light source disposed on the second optical axis is guided to the subject's eye via the photographing optical system, and the focus reflected from the subject's eye via the photographing optical system. A wavelength separating unit that guides light on the second optical axis and reflects or transmits an image of the eye to be inspected; and a light source for focusing that is disposed between the wavelength separating unit and the light source for focusing. Guides the focused light from the A space separating unit that guides the focused light guided on the second optical axis to the focused state detecting unit on an optical path different from an optical path from the focusing light source to the wavelength separating unit. It is configured as a feature.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, an illuminating means for illuminating the eye to be examined and an illuminating light of the illuminating means are arranged on an optical axis of the photographing means. Having a perforated mirror that reflects toward the eye to be inspected, the perforated mirror having a first opening through which an image of the eye to be examined passes, and a first aperture through which focusing light from the focusing light source passes. And two openings.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the illuminating means has a ring diaphragm for regulating illumination light projected on the perforated mirror to a predetermined range, The ring diaphragm is configured to have an opening for projecting illumination light only around the first opening except for the second opening on the reflection surface of the perforated mirror. I have.

According to a seventh aspect of the present invention, there is provided a photographing means for photographing an image of an eye to be inspected, and a focusing light serving as a reference for judging a degree of focusing of the image of the eye to be inspected on the photographing means. A focusing light source for projecting light to the eye to be examined, and a focusing light projected by the focusing light source passing through an opening of the focusing light source to form a predetermined shape. In an ophthalmologic imaging apparatus having a focus indicator disposed at a position, the light intensity of the focus light attenuates as the opening of the focus indicator moves away from a portion located on the optical axis of the focus light. It is characterized in that it has a shape whose width increases according to the degree.

[0021]

An embodiment of the present invention will be described below in detail with reference to the drawings. 1 is a configuration diagram of an optical system of the fundus camera according to the present embodiment, FIG. 2 is a configuration diagram for explaining an optical path of a main part of the optical system of FIG. 1, and FIG. 3 is an enlarged view of a main part of the optical system of FIG. FIG. 4 is a perspective view, FIG. 4 is a block diagram showing an electrical configuration of the fundus camera, and FIG. 5 is an explanatory diagram for explaining a main part of the optical system of FIG. In FIG. 1, a fundus camera mainly includes an illumination optical system 10 for illuminating the fundus of the eye 1 to be examined, a photographing optical system 30 for photographing a fundus image of the eye 1 to be examined, and an image of the eye to be examined, which will be described later. A focusing optical system 40 for focusing on the CCD 32.

As shown in FIG. 1, the illumination optical system 10 includes an illumination light source 11, an infrared transmission filter 12 that transmits light of 750 nm or more, lenses 13 to 15, and a wavelength separation mirror 62 that reflects light of 850 nm or more. It comprises a ring diaphragm 16, a perforated mirror 17, a wavelength separating mirror 18 for reflecting light of 850 nm or less, and an observation CCD 19.

The illumination light emitted from the illumination light source 11 and passing through the infrared transmission filter 12 passes through the lenses 13 and 14,
The ring diaphragm 16 is reached. As shown in FIG. 3B, the ring diaphragm 16 has a substantially horseshoe-shaped opening 16a (the reason for the horseshoe-shaped opening will be described later), and allows light to pass only through this opening 16a. , And regulates light within a predetermined range. here,
By blocking the illumination light projected to the center of the cornea of the subject's eye 1 while blocking only the illumination light projected to the periphery of the cornea, generation of noise light generated when the light is projected to the center of the cornea is prevented. Preventing. Illumination light regulated in this way is
As shown in FIG. 1, the perforated mirror 1 passes through the lens 15 and
It is led to 7.

As shown in FIG. 3 (a), the perforated mirror 17 has an opening 17a at the center thereof, allows light to pass through the opening 17a, and transmits light through the non-opening 17b.
Reflects light at The illumination light reflected by the non-opening portion 17b is guided to the fundus of the eye 1 through the objective lens 2 as shown in FIG. Then, the illumination light reflected by the fundus passes through the objective lens 2, the opening 17 a of the perforated mirror 17, and a focusing lens 31 described later, is reflected by a wavelength separating mirror 46 described later, and transmits through a wavelength separating mirror 47. Then, the reflected light is reflected by the wavelength separation mirror 18 and the observation CCD
It is led to 19. The illumination light guided to the observation CCD 19 is displayed on a monitor (not shown) and illuminated by the examiner as a fundus image.

As shown in FIG. 1, the photographing optical system 30 includes a focusing lens 31, a photographing CCD 32, and a photographing light source 33. The photographing light source 33 is arranged on the optical axis of the illumination optical system 10, and after the photographing light emitted from the photographing light source 33 passes through the wavelength separation mirror 62 and the ring diaphragm 16 that transmits light of 850 nm or less, The light is reflected by the non-opening portion 17b of the perforated mirror 17, and is guided to the fundus of the subject's eye 1. The imaging light reflected by the fundus of the eye 1 to be examined, that is, the fundus image of the eye 1 to be examined,
After passing through a wavelength separating mirror 46 that transmits light of 750 nm or less through the opening 17a and the focusing lens 31, the light is guided to the photographing CCD 32 and photographed by the photographing CCD 32.

As shown in FIG. 1, the focusing optical system 40
A focusing light source 41 that emits a focusing light of 00 nm, a focus indicator 42, lenses 43 and 44, small mirrors 45, a wavelength separating mirror 46 that transmits light of 750 nm or less, a wavelength separating mirror 47 that reflects light of 850 nm or more, and 2 split receiver 4
8. First, the focusing light source 41 emits focused light serving as a reference for determining the degree of focusing.
The focused light passes through the opening 42a of the focus indicator 42, and is thereby narrowed down to a shape corresponding to the opening 42a (this shape will be described later). Here, the focusing light source 41 is disposed at a position conjugate with the reflection surface of the small mirror 45, and the focused light passing through the opening 42 a is reflected by the small mirror 45 via the lens 43. Then, the focused light is reflected by the wavelength separation mirrors 47 and 46, and the focusing lens 31,
Through the perforated mirror 17.

As shown in FIG. 3, the perforated mirror 17 has
An opening 17c is provided in the vicinity of the opening 17a, and the focused light is guided to the fundus of the eye 1 through the opening 17c (this opening 17c will be described later).
As shown in FIG. 1, the focused light reflected by the fundus of the subject's eye 1 passes through the aperture 17 a of the perforated mirror 17 and the focusing lens 3.
1. Two-divided light receiver 4 via wavelength separation mirrors 46 and 47
It is led to 8.

Here, the focus indicator 42 and the photographing CCD 3
The two- and two-divided photodetectors 48 are conjugated to each other. If the focusing lens 31 is positioned so that the fundus of the subject's eye 1 and the imaging CCD 32 are conjugated to each other, the focus indicator 42 focuses. The light is received by the two-divided light receiver 48 in a connected state, that is, in a state where the degree of focusing is appropriate. Further, the focus indicator 42 is arranged so as to be located at the center of the optical axis of the two-piece light receiver 48. For this reason, the degree of focusing of the focus index image on the two-divided light receiver 48 is detected, and the degree of focusing is optimized, so that the degree of focusing of the image of the subject's eye 1 on the imaging CCD 32 is optimized. can do.

This two-divided light receiver 48 includes two light receivers 4
8a and 48b are provided.
48b, the focused light is located at the center of the light receivers 48a and 48b when the degree of focusing is appropriate, and the light receivers 48a and 48b are adjusted according to the degree of deviation when the degree of focusing is incorrect.
It is arranged so as to be shifted to any one side of b. For example, assuming that the light amounts of the focused light received by the light receivers 48a and 48b (hereinafter, simply referred to as “light reception amounts”) are Q1 and Q2, respectively, Q1> Q2 at the time of the front focus, and Q1 <at the time of the rear focus. Q2, Q1 = Q2 when focusing is appropriate. The degree of focusing can be adjusted by moving the focusing lens 31 in the direction of the optical axis in the same manner as in the prior art, and by moving the focusing lens 31, Q1 = Q2 to perform the focusing operation. Will be Details of the focusing operation will be described later.

As shown in FIG. 1, the fundus camera has an alignment light source 60 that emits 900 nm alignment light for alignment, and 6 light sources for fixation.
A fixation light source 61 that emits fixation light of 00 nm is provided. The alignment light generated from the alignment light source 60 is reflected by the subject's eye 1,
And a wavelength separating mirror 6 that reflects light of 850 nm or more through the opening 16a of the ring diaphragm 16.
The light is reflected by the lens 2, and is guided to the observation CCD 19 via the lens 64 and the wavelength separation mirror 18 which reflects light of 850 nm or less. The examiner observes the alignment light guided to the observation CCD 19 in this manner, and adjusts the position of the fundus camera with respect to the subject's eye so that the alignment index is at a predetermined position on a monitor (not shown). The fixation light emitted from the fixation light source 61 is applied to the ring diaphragm 16.
The eye is guided to the subject's eye 1 via the small mirror 63 and the perforated mirror 17 provided above, and the fixation work is performed by showing the fixation light to the subject.

Among the optical systems configured as described above, the characteristic parts of the present embodiment will be described below. First, in the present embodiment, a configuration that does not use a half mirror that causes a decrease in light amount, or a configuration that does not use an electric movable mirror (quick return mirror) that causes an increase in power consumption, complication, and vibration of a fundus camera. Presenting the fixation point to the subject for fixation of the imaging part necessary for non-mydriatic fundus photography, alignment instruction to the examiner to supplement alignment detection accuracy that is not sufficient with observation alone, observation only In this case, automatic focusing instead of insufficient focus detection, observation with invisible light, and imaging with visible light are realized.

First, the configuration for presenting the fixation point to the subject will be specifically described. In FIG. 1, the fixation light source 61 and the small mirror 63, the small mirror 63 and the perforated mirror 17, the fixation light source 61 and the subject's pupil, and a fixation index (not shown) illuminated by the fixation light source 61 and Optometry 1
Are placed substantially conjugate with each other. Fixation light (visible light) emitted from the fixation light source 61 is reflected by the small mirror 63 and the non-opening portion 17b of the perforated mirror 17, and enters the eye 1 through the objective lens 2. The fixation point is presented to the subject. The light source for fixation uses only a very small area of the subject's pupil.

Next, the configuration for instructing the examiner to perform alignment and performing observation using invisible light will be specifically described. In FIG. 1, the illumination light emitted from the illumination light source 11 includes an infrared transmission filter 12 and a wavelength separation mirror 62.
When the light is transmitted, the wavelength is limited to 750 nm to 850 nm by the infrared transmission filter 12 and the wavelength separation mirror 62, and the fundus of the eye 1 is illuminated. The observation light reflected by the fundus passes through the opening 17a of the perforated mirror 17,
Reflected by the wavelength separation mirror 46 and the wavelength separation mirror 18,
An image is formed on the observation CCD 19. In this way,
The examiner can observe the subject's eye 1 with invisible light. On the other hand, the 900 nm alignment light source 60 is optically arranged at an infinity position with respect to the cornea of the subject's eye 1, and forms an image substantially at the pupil position of the subject's eye. Since the alignment light source 60 is arranged so that the alignment index image is formed outside the opening 17a of the perforated mirror 17, the alignment index image is reflected outside the opening 17a of the perforated mirror 17, The light passes through the opening 16 a of the ring diaphragm 16, is reflected by the wavelength separation mirror 62, passes through the lens 64 and the wavelength separation mirror 18, and forms an image on the observation CCD 19. Since this alignment index image is displayed so as to be superimposed on the image of the eye to be inspected, an alignment instruction can be given to the examiner. The lens 64 is disposed so that the observation CCD 19 and the ring diaphragm 16 are substantially conjugate.

Next, the configuration for performing automatic focusing and photographing with visible light will be specifically described. In FIG. 1, the imaging illumination light limited to 850 nm or less by the wavelength separation mirror 62 is reflected by the perforated mirror 17 and illuminates the fundus of the eye 1 through the objective lens 2. The imaging light reflected by the fundus of the eye 1 passes through the opening 17a of the perforated mirror 17, is limited to 750 nm or less by the wavelength separation mirror 46, and forms an image on the imaging CCD 32. In the present embodiment, imaging with visible light can be performed in this manner. On the other hand, the 900 nm focusing light source 41 illuminates the focus index 42, and the small mirror 45 and the wavelength separation mirror 4
7. The aperture mirror 17 is reflected by the wavelength separation mirror 46,
The focus target image is projected on the eye 1 through the opening 17c and the objective lens 2. That is, the focused light reaches the subject's eye 1 through a path 49 indicated by a solid line in FIGS. Here, the alignment light source 41, the small mirror 45, and the opening 17c of the perforated mirror 17 are arranged conjugate with each other,
For alignment, only a very small area of the subject's pupil area is used. The focus index is conjugated to the photographing CCD 32 and the two-divided light amount detector 48. The focus index image projected on the fundus of the eye 1 is reflected by the fundus of the eye 1, passes through the opening 17a of the perforated mirror 17, is reflected by the wavelength separating mirror 46 and the wavelength separating mirror 47, and is divided into two light quantity detectors. At 48, light is received. That is, the light reaches the two-divided light amount detector 48 through a path 50 indicated by a broken line in FIGS. As described above, the focused light is guided through the paths 49 and 50 that do not overlap each other, so that the automatic focusing is performed without causing the focused light to be attenuated by the half mirror.

In order to guide the focused light to the subject's eye 1 through the path 49, the perforated mirror 17 is provided at the center of the perforated mirror 17 as shown in FIG. Opening 1 as a first opening for transmitting an image of the eye to be examined
In addition to 7a, an opening 17c as a second opening for transmitting the focused light is provided. The opening 17c is formed substantially corresponding to the width and position through which the focused light passes, and is formed so that a part thereof is in contact with the opening 17a.

In response to the formation of the perforated mirror 17 as described above, the ring diaphragm 16 of the illumination optical system 10 has its aperture 16a
7 of the reflection surface, that is, the opening 1 of the non-opening 17b.
It is formed in a substantially horseshoe shape so that the illumination light is projected only around the opening 17a excluding the periphery of 7c. That is, the opening 16a is formed concentrically with respect to the opening 17a and has a diameter slightly larger than that of the opening 17a, and is not completely annular, and is formed in a non-opening shape at a portion corresponding to the opening 17c.

In this embodiment, as shown in FIG. 5, the aperture 42a of the focus index 42 of the focusing optical system 40 is used.
Is a special shape different from the conventional one. More specifically, the opening 42a has a shape in which the width increases as the light intensity of the focused light decreases as the distance from the portion located on the optical axis of the focused light increases. That is, as shown in FIG. 5, a portion of the aperture 42a located on the optical axis of the focused light is denoted by P1, a portion of the aperture 42a separated from the P1 by a distance L1 in the longitudinal direction is denoted by P2, and a portion P2 is denoted by P2. The light intensity of the passing focused light is 1 to the light intensity of the focused light passing through the portion P1.
Assuming that attenuation is 0%, the opening 4 at the position P2
The width W2 in the lateral direction of 2a is the opening 42 at the position P1.
It is formed to be 10% wider than the width W1 of a. Therefore, as shown in the upper right graph of FIG. 5 (the horizontal axis is the light intensity, and the vertical axis is the distance in the longitudinal direction of the opening 42a),
Both the light intensity of the light passing through the width W1 and the light intensity of the light passing through the width W2 become the light intensity K1, and as shown in the lower right graph of FIG. The output difference of the photodetector with respect to the amount of light varies linearly, and the focus detection accuracy can be equalized regardless of the magnitude of the amount of deviation.

Next, the electrical configuration of the fundus camera will be described. As shown in FIG. 4, the fundus camera includes a release switch 100 for instructing the start of photographing, a storage unit 110 for storing various values to be described later, and a focusing lens driving motor for driving a focusing lens. A control unit 140 that controls the release switch 120, the release switch 100, the storage unit 110, and the focusing lens drive motor 120 is provided.

Further, as shown in FIG.
Is configured to include a movement amount storage unit 111 and a control unit 140
Is configured to include a difference calculation unit 141, a focusing lens driving unit 144, a photographing completion determination unit 145, a focusing completion determination unit 146, and a focusing stop unit 147.

The moving amount storage unit 111 stores in advance the moving amount of the focusing lens required for focusing in accordance with the degree of focusing. In this embodiment, the degree of focusing is detected as a difference between the amount of light received by the light receiver 48a and the amount of light received by the light receiver 48b. Specifically, the light receiver 48a,
The light reception amount is output as a voltage value in each of the 48b, and a difference between the two voltage values is calculated by a difference calculation unit 141 described later.

Accordingly, the moving amount storage unit 111 stores the voltage value as the difference and the moving amount of the focusing lens necessary to eliminate the difference, that is, to make the degree of focusing appropriate. For example, when the voltage value is “0.1 volt”, the moving amount of the focusing lens is “1”.
mm ", the moving amount of the focusing lens is" 0 mm "(no movement required) when the difference in the received light amount is" 0 volt ", and the focusing lens when the difference in the received light amount is" -0.1 volt ". Is "-1 mm" (minus indicates movement in the opposite direction to plus).

The difference calculator 141 calculates the difference between the amount of light received by the light receiver 48a and the amount of light received by the light receiver 48b. The difference calculator 141 and the two-divided light receiver 48 use the CCD 21 for photographing. Focusing state detecting means for detecting the degree of focusing of the image of the subject's eye 1 with respect to the image is constructed.

The focusing lens driving section 144 includes the difference calculating section 1
The moving amount of the focusing lens 31 corresponding to the difference of the received light amount calculated in 41 is read from the moving amount storage unit 111, and the focusing lens driving motor 120 is driven to drive the focusing lens 31 by the read amount of movement. To output a control signal. The photographing completion determining unit 145 determines whether or not photographing by the photographing CCD 21 has been completed. The focusing completion determining unit 146 determines whether focusing by the focusing unit has been completed. Focus stop unit 1
47, when the focusing completion determining unit 145 determines that the focusing by the focusing unit is completed, the photographing completion determining unit 145 determines that the photographing by the photographing CCD 21 is completed. The focus operation is stopped again. The operations of the photographing completion determining unit 145, the focusing completion determining unit 146, and the focusing stopping unit 147 will be described later.

The difference calculation unit 141, the focusing lens driving unit 144, the photographing completion determining unit 145, the focusing completion determining unit 146, and the focusing canceling unit 147 are a microprocessor and a program executed on the microprocessor. Can be realized by: Further, the movement amount storage unit 11
The one and allowable range storage unit 112 can be configured by one or a plurality of storage elements such as a nonvolatile IC memory or a magnetic memory.

Next, the operation from focusing to photographing of the subject's eye 1 in this embodiment will be described. First, when the subject turns on the power of the fundus camera, the observation light source 11, the focusing light source 41, the alignment light source 60, and the fixation light source 61 are turned on. When the examiner adjusts the approximate position of the fundus camera while the subject is fixed to the chin rest (not shown) and the forehead, the fundus image of the subject's eye 1 and the alignment index image are displayed on a monitor (not shown). Is displayed. In this state, the subject can see the fixation target. The focus index is also projected on the fundus of the subject's eye 1. In this state, the photographing completion determination unit 145
Holds a signal indicating that the shooting is not completed.

When the amount of focused light projected by the focusing light source 41 and reflected by the subject's eye 1 is detected by the light receivers 48a and 48b, the difference between the two received light amounts is calculated by the difference calculating means 141. Is calculated. When the difference is input, the focusing lens driving unit 144 refers to the content stored in the moving amount storage unit 111 and reads the moving amount of the focusing lens 31 corresponding to the input difference. For example, the input difference is "0.1 volt"
In the case of (1), the moving amount “1 mm” of the focusing lens is read.

Then, the focusing lens driving section 144 outputs a control signal to the focusing lens driving motor 120 so as to move the focusing lens 31 by the read movement amount “1 mm”. Then, the focusing lens drive motor 120 moves the focusing lens 31 by “1 mm” according to the control signal,
When the movement is completed, a signal indicating the completion is output to the focusing completion determination unit 146. This focusing completion determining unit 146
In, when an output signal indicating that the driving of the focusing lens 31 is completed is received from the focusing lens driving motor 120, a signal indicating that the focusing is completed is held.

Here, the focusing stop unit 147 monitors the state of the focusing completion determining unit 146, and the focusing completion determining unit 146.
Indicates that the focusing has been completed, the input of the amount of focused light output to itself from the light receivers 48a and 48b to the difference calculation unit 141 is stopped. On the other hand, when the focusing completion determination unit 146 does not indicate that the focusing is completed, the light amount of the focusing light output to itself from the light receivers 48a and 48b is input to the difference calculating unit 141. . Then, as described above, the light amount is calculated by the difference calculating means 14.
Only when the value is input to 1, the series of focusing operations described above is performed. For this reason, once the in-focus state becomes appropriate, since the re-focusing operation is not started until the photographing is completed, the problem that the in-focus operation is started carelessly and it is difficult to complete is solved. You.

The examiner then instructs the subject to look at the fixation light source 61 shown in FIG. The examiner confirms that the subject is looking at the fixation light source 61, that is, that the imaging region is in a desired state, and presses the release switch 100. The control unit 140 shown in FIG.
When 0 is pressed, an automatic alignment mechanism (not shown) is controlled to automatically perform alignment work in the X, Y, and Z directions. When this alignment work is completed, the fundus image of the eye to be inspected 1 is automatically deleted. Take an image. The photographing completion determining unit 145 determines that the photographing is completed in this manner, outputs a control signal to the focusing completion determining unit 146, and notifies the focusing completion determining unit 146 that the focusing is not completed. Hold the signal.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, but may be variously modified within the scope of the technical idea described in the claims. These different modes will be described below. In the above embodiment, the ophthalmologic photographing apparatus has been described as an example of a fundus camera. However, the present invention is similarly applicable to ophthalmologic photographing apparatuses other than the fundus camera. First, in the above embodiment, the two-divided light receiver 48
And the difference calculation unit 141 detects the degree of focusing of the image of the subject's eye 1 with respect to the photographing CCD 32. However, in order to detect the degree of focusing, the two-divided light receiver 48 and the difference calculation unit 141 are used. Any known means other than the above may be used.

The optical system for achieving the above-mentioned quick focusing operation is not limited to the above-described embodiment, and any known optical system may be used. On the other hand, a fundus camera may be configured by combining the optical system for achieving the spatial separation and the wavelength separation with an electrical configuration other than the above. Alternatively, a conventional index may be used as the focus index 42, and conversely, the focus index 42 in the above-described embodiment may be used in any fundus camera other than the above-described embodiment.

【The invention's effect】

As described above, according to the first and second aspects of the present invention, the movement amount for storing the movement amount of the focusing lens required for focusing in correspondence with the focus shift amount. Amount storage means and a movement amount corresponding to the amount of defocus detected by the focus state detection means are read from the movement amount storage means, and the focusing lens is driven based on the read movement amount. With the provision of the focusing lens driving means, the focusing operation can be completed based only on the degree of focusing at the start of the focusing operation, and there is no need to continuously detect the degree of focusing. Therefore, the focusing operation can be quickly performed even on the subject who frequently blinks.

According to a third aspect of the present invention, a photographing completion judging means for judging whether or not the photographing by the photographing means is completed, and judging whether or not the focusing by the focusing means is completed. When the completion of focusing by the focusing unit is determined by the focusing completion determining unit and the focusing completion determining unit, the completion of shooting by the shooting unit is determined by the shooting completion determining unit. Until the focusing operation is completed, the focusing operation is inadvertently restarted until the photographing is completed after the focusing operation is completed. Therefore, it is possible to smoothly perform from the completion of focusing to the completion of shooting.

Further, according to the present invention, the focusing light from the focusing light source disposed on the second optical axis separated from the optical axis of the photographing optical system is transmitted through the photographing optical system. A wavelength separation unit that guides the focused light reflected from the subject's eye through the imaging optical system onto the second optical axis while guiding the image to the subject's eye, and reflects or transmits the image of the subject's eye. Disposed between the wavelength separation unit and the focusing light source, and guides the focused light from the focusing light source to the wavelength separation unit, and the wavelength separation unit places the focused light on the second optical axis. And a space separating unit that guides the focused light guided to the focusing state detecting unit on an optical path different from the optical path from the focusing light source to the wavelength separating unit, so that the imaging optical system The focusing lens can be used for focusing work, while the focusing lens Since the optical path of the optical system can be separated without using a half mirror, it is not necessary to provide an interlocking mechanism for moving a focusing light source or the like in accordance with the driving of the focusing lens, and the overall configuration can be made compact. At the same time, it is possible to prevent the photographing light and the focusing light from being attenuated by the half mirror.

Further, according to a fifth aspect of the present invention, there is provided an illumination means for illuminating the eye to be inspected, and a hole arranged on an optical axis of the photographing means for reflecting illumination light of the illumination means toward the eye to be inspected. An opening mirror, wherein the perforated mirror has a first opening through which the image of the eye to be examined passes, and a second opening through which focusing light from the focusing light source passes. Accordingly, the focused light can be guided to the subject's eye from a path different from the optical axis of the imaging unit, and spatial separation can be achieved.

According to a sixth aspect of the present invention, the illuminating means has a ring diaphragm for regulating illumination light projected on the perforated mirror to a predetermined range, and the ring diaphragm is provided on the perforated mirror. By having an opening for projecting illumination light only around the first opening except for the second opening of the reflection surface, the illumination light can be transmitted through the first opening or the second opening. It can be prevented from being reflected and scattered by the edge of the part.

According to a seventh aspect of the present invention, as the aperture of the focus indicator is moved away from a portion located on the optical axis of the focused light, the light intensity of the focused light is reduced. Since the width becomes wider correspondingly, the luminous intensity of the focused light changes linearly over the entire opening regardless of the distance from the focused light, and a linear output can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical system of a fundus camera according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an optical path of a main part of the optical system of FIG. 1;

FIG. 3 is an enlarged perspective view of a perforated mirror and a ring diaphragm of the optical system of FIG. 1;

FIG. 4 is a block diagram showing an electrical configuration of the fundus camera of FIG. 1;

FIG. 5 is an explanatory diagram for explaining a focus index of the optical system of FIG. 1;

FIG. 6 is an explanatory diagram for explaining a focus index of a conventional optical system.

FIG. 7 is a configuration diagram of an optical system of a conventional fundus camera.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Examinee's eye 2 Objective lens 10 Illumination optical system 11 Illumination light source 16 Ring diaphragm 17 Perforated mirror 18, 46, 47, 62 Wavelength separation mirror 19 Observation CCD 30 Imaging optical system 31 Focusing lens 32 Imaging CCD 40 Focusing Optical system 41 Light source for focusing 42 Focusing index 45 Small mirror 48 Two-part receiver

Claims (7)

[Claims] A photographing means for photographing the eye to be inspected; a focusing lens for focusing the image of the eye to be examined on the photographing means; and a defocus from the in-focus state of the image of the eye to be examined in the photographing means. A focus state detecting means for detecting an amount, a moving amount storing means for storing a moving amount of the focusing lens required for focusing in correspondence with the amount of defocus. A focus lens that reads a movement amount corresponding to the amount of defocus detected by the focus state detection means from the movement amount storage means, and drives the focus lens based on the read movement amount. An ophthalmologic photographing apparatus comprising: a driving unit. 2. A light source for irradiating the subject's eye with measurement light for detecting an amount of defocus from the in-focus state, a first detection unit and a second detection And a two-division light amount detection unit that receives the measurement light reflected by the eye to be inspected; a light reception amount detected by the first detection unit; and a light reception amount detected by the second detection unit. And a difference calculating means for calculating a difference from the received light amount, wherein the moving amount storing means stores a moving amount of the focusing lens required to eliminate the difference in correspondence with the difference. Wherein the focusing lens driving means reads a movement amount corresponding to the difference calculated by the difference calculation means from the movement amount storage means, and drives the focusing lens by the read movement amount. The ophthalmologic photographing apparatus according to claim 1. 3. An ophthalmologic photographing apparatus comprising: photographing means for photographing an eye to be examined; and focusing means for focusing an image of the eye to be examined on the photographing means. Imaging completion determining means for determining whether or not focusing by the focusing means has been completed; focusing completion determining means for determining whether or not focusing by the focusing means has been completed; focusing by the focusing means having been completed by the focusing completion determining means And focusing stop means for stopping the refocusing operation by the focusing means until the completion of the photographing by the photographing means is determined by the photographing completion determining means. An ophthalmologic photographing apparatus, characterized in that: An imaging optical system for imaging the eye to be inspected; a focusing light source for irradiating the eye with measurement light for detecting an amount of defocus from a focused state; An in-focus state detecting means for detecting an amount of defocus from an in-focus state of the image of the eye to be inspected. The ophthalmologic photographing apparatus further comprising: a second optical axis separated from an optical axis of the imaging optical system. The focused light from the arranged light source for focusing is guided to the subject's eye via the photographing optical system, and the focused light reflected from the subject's eye via the photographing optical system is converted to the second light. Wavelength separating means for guiding on the axis, and reflecting or transmitting the image of the eye to be examined, disposed between the wavelength separating means and the focusing light source,
The focusing light from the focusing light source is guided to the wavelength separation unit, and the focusing light guided on the second optical axis by the wavelength separation unit is separated from the focusing light source by the wavelength separation unit. An ophthalmologic photographing apparatus, comprising: a space separating unit that guides the in-focus state detecting unit in an optical path different from an optical path leading to the unit. 5. An illumination device for illuminating the eye to be inspected, and a perforated mirror disposed on an optical axis of the photographing device and reflecting illumination light of the illumination device toward the eye to be inspected. The opening mirror has a first opening through which the image of the eye to be examined passes, and a second opening through which focusing light from the focusing light source passes. Ophthalmic photography equipment. 6. The illumination means has a ring diaphragm for restricting illumination light projected on the perforated mirror to a predetermined range, and the ring diaphragm has a second opening in a reflection surface of the perforated mirror. 6. The ophthalmologic photographing apparatus according to claim 5, further comprising an opening for projecting illumination light only around the first opening except for a part. 7. A photographing means for photographing an image of an eye to be inspected, and a focusing light for projecting focused light serving as a reference for judging a degree of focusing of the image of the eye to the photographing means to the eye to be inspected. A focusing light source, and a focus indicator disposed at a substantially conjugate position with a photographing surface of the photographing means, wherein the focused light projected by the focusing light source passes through its own opening to have a predetermined shape. In the ophthalmologic photographing apparatus, as the aperture of the focus indicator is moved away from the portion located on the optical axis of the focused light, the width increases in accordance with the degree to which the light intensity of the focused light is attenuated. An ophthalmologic photographing apparatus characterized in that it has a shape.