JPH08206082A - Fundus camera - Google Patents

Abstract

PURPOSE: To do focusing in a simple configuration with high precision. CONSTITUTION: A light flux from a light source for observing 11 is reflected by an eyeground Er and put incident to a TV camera 20, and the eyeground image Pr is displayed on a TV monitor 22. Light flux from another light source 1 for focusing is passed through a dicroic mirror 4 to proceed the same route as the light flux from the observing light source 11, and the focused flux image Pf is displayed on the TV monitor 22. At the time of photographing, a focusing lens 14 is moved by a driving means 13, and focusing is made so that the focused flux image Pf is positioned in the middle between two reference marks M produced by a symbol circuit in a signal processor 21. After convergence is generated, a photographing button is pushed, and a light source for photographing 5 emits light in synchronization with springing-up of a spring-up mirror 16, and the eyeground image is recorded on a film 17.

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 In a conventional fundus camera, an image is taken by using a focused light beam projection system having a movable portion or a special optical member for separating a focused light beam from a pupil. ing.

[0003]

However, in the above-mentioned conventional example, the structure is complicated because the movable portion and the special optical member are used. Further, since the focusing lens is not used effectively, there is a problem that the measurement accuracy is lowered.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a fundus camera having a simple device configuration and capable of performing highly accurate focusing.

[0005]

A fundus camera according to the present invention for achieving the above object projects a focused light beam onto a fundus of an eye to be inspected from a predetermined position outside a photographing light beam on a pupil plane of the eye to be inspected. In the fundus camera having a projection optical system for receiving, and a light receiving optical system that receives the fundus reflected light flux of the focused light flux to the photoelectric sensor array via the photographing diaphragm and the focusing lens, the predetermined position and the photographing light flux are Focusing is performed according to the position of the received light beam of the light receiving optical system in the connecting direction.

[0006]

In the fundus camera having the above-described structure, the projection optical system projects the focused light beam from the predetermined position outside the photographing light beam on the pupil surface of the eye to be examined to the fundus of the eye to be examined, and the light receiving optical system projects the focused light beam. The fundus reflected light flux is received by the photoelectric sensor array via the photographing diaphragm and the focusing lens, and focusing is performed by the position of the light-receiving light flux of the light-receiving optical system in the direction connecting the predetermined position and the photographing light flux.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail based on the illustrated embodiments. FIG. 1 is a configuration diagram of the first embodiment and is an example of a non-mydriasis type fundus camera. On the optical path O1 from the focusing light source 1 to the subject's eye E, a diaphragm 2 conjugated to the fundus Er of the subject's eye E, a lens 3, a dichroic mirror 4 for reflecting a light beam having a wavelength of about 800 nm or more, a strobe light source, etc. Shooting light source 5,
A ring diaphragm 6, a lens 7, a perforated mirror 8, and an objective lens 9 which are conjugated to the pupil Ep are sequentially arranged. A lens 10 and an observation light source 11 that emits an infrared light flux are arranged on the optical path O2 in the reflection direction of the dichroic mirror 4.

FIG. 2 is a front view of the diaphragm 2, in which a rectangular or slit-shaped opening 2a is provided near the center. The diaphragm 2 is not always necessary, but it is preferably arranged when the image on the television monitor is visually observed to perform focusing. Further, the focusing light source 1 is composed of a near-infrared LED or the like that is conjugate with the pupil Ep of the eye E and emits a light flux having a peak in the near-infrared light flux with a wavelength of 800 nm or less, and is slightly displaced from the optical path O1. It is arranged.

Further, on the optical path O3 behind the perforated mirror 8, a photographing diaphragm 12, a focusing lens 14, an imaging lens 15, a flip-up mirror 16, which are movable along the optical path O3 by a driving means 13, The films 17 are arranged in order.

Further, a mirror 18, a lens 19, and a television camera 20 such as a CCD camera are sequentially arranged on the optical path O4 in the reflection direction of the flip-up mirror 16, and the television camera 20 internally has a symbol generating circuit. A signal processor 21 and a television monitor 22 each having a computer for calculating and focusing a video signal are connected.

The light flux from the observation light source 11 passes through the lens 10, is reflected by the dichroic mirror 4, passes through the photographing light source 5, the ring diaphragm 6, the lens 7, is reflected by the perforated mirror 8, and passes through the objective lens 9. The light enters from the pupil Ep and the fundus Er
Illuminate. Further, the light flux from the focusing light source 1 is a diaphragm 2,
The fundus Er is illuminated through the lens 3 and the dichroic mirror 4 and the same optical path as the light flux from the observation light source 11.

FIG. 3 is an explanatory view of the positional relationship of the light fluxes on the pupil Ep plane. The ring light flux Lr by the ring diaphragm 6 is projected around the central photographing light flux Lp by the shooting diaphragm 12. Further, since the focusing light source 1 is slightly deviated from the optical axis of the optical path O1, the focusing light flux Lf generated by the focusing light source 1 is the photographing light flux.
Projected from below Lp.

The reflected light flux from the fundus Er returns through the same optical path,
It passes through a perforated mirror 8, a photographing diaphragm 12, a focusing lens 14, and an imaging lens 15, is reflected by a flip-up mirror 16 and a mirror 18, passes through a lens 19 and enters a TV camera 20, and a fundus image on a TV monitor 22. Pr, the two reference marks M generated by the symbol generating circuit in the signal processor 21, and the focused light flux image Pf by the focused light flux Lf are displayed.

At the time of photographing, the driving means 13 is driven to move the focusing lens 14 so that the focused light flux image Pf is in the middle of the two reference marks M to perform focusing. The position of the reference mark M is programmed in the computer in the signal processor 21 so as to coincide with the position of the focused light flux image Pf when the fundus Er and the imaging surface of the film 17 or the television camera 20 are conjugated. Therefore, the position of the reference mark M moves up and down as the focusing lens 14 moves.

When the examiner visually focuses, the focusing lens 14 is manually moved while observing the focused light flux image Pf and the reference mark M on the television monitor 22. When the focus is achieved, the focused light flux image Pf is also at the intermediate position of the reference mark M on the television monitor 22, but when the focus is not achieved, the reference mark M is at the intermediate position of the focused light flux image Pf. Shifts more vertically than Further, if the focused light flux Lf enters the pupil Ep from the lateral direction of the photographing light flux Lp, the focused light flux image Pf is laterally displaced due to focusing. In this way,
Since the focused light flux image Pf shifts on the pupil Ep in the straight line direction connecting the center of the photographing light flux Lp and the center of the focused light flux Lf, the position in that direction is determined to perform focusing.

On the other hand, in the case of performing focusing by autofocus, the image signal from the television camera 20 at the center of the screen is used for image processing by the signal processor 21, and a focused light flux image is obtained.
Calculate the vertical position of Pf. The signal processor 21 determines the moving direction and the moving amount of the focusing lens 14 from the difference between the position and the position of the focused light flux image Pf when the fundus Er is conjugated with the film 17 or the television camera 20. Then, the driving means 13 moves the focusing lens 14 to perform focusing.

The focusing operation is performed in this way, and after the subject is in focus, the examiner presses the photographing button and the photographing light source 5 emits light in synchronization with the flip-up of the flip-up mirror 16 and the fundus image Pr.
Is recorded on the film 17.

FIG. 4 is a block diagram of the focused light beam projection system of the second embodiment, in which the flat plate prisms 31 having the reflecting surface 31a are arranged on the optical path O1 of the first embodiment, and the flat plate prism 31 is arranged.
A lens 32, a diaphragm 33 conjugated to the fundus Er, and a focusing light source 34 are sequentially arranged in the incident direction of.

A light beam from the focusing light source 34 passes through the diaphragm 33 and the lens 32, is totally reflected once in the flat plate prism 31, and is guided to the optical path O1 of the fundus illuminating optical path in FIG. In this case,
Since the total reflection is performed in the flat plate prism 31, the incident angle on the reflection surface 31a becomes small, and the wavelength division can be performed more efficiently.

FIG. 5 is a block diagram of the focused light beam projection system of the third embodiment. It shows the incident direction of the small mirror 41 provided in the vicinity of the perforated mirror 8 and the photographic diaphragm 12 of the first embodiment. Light path
A lens 42, a diaphragm 43 conjugated to the fundus Er, and a focusing light source 44 are arranged on O5.

The light beam from the focusing light source 44 passes through the diaphragm 43 and the lens 42, is reflected by the small mirror 41, and is guided to the optical path O3. In this case, in FIG. 3, the focused light flux Lf is projected between the photographing light flux Lp and the ring light flux Lr, and the focused light flux Lf is close to the photographing light flux Lp, but the resolution deteriorates, but the pupil Ep
The influence of internal aberration is reduced.

FIG. 6 is a block diagram of the observation optical system of the fourth embodiment, which is an example of a mydriasis type fundus camera for observing the fundus Er with a visible light beam and focusing with a near-infrared light beam. Instead of observing on the television monitor 22 of the first embodiment, a dichroic mirror 51, a lens 52, a paper surface for reflecting a visible light beam and transmitting an infrared light beam are provided on the optical path O6 in the reflection direction of the flip-up mirror 16 of FIG. A cylindrical lens 53 which has a convex power in the vertical direction and improves the light-collecting efficiency, and a one-dimensional CCD 54 which is arranged parallel to the generatrix of the cylindrical lens 53 and is conjugate with the surface of the film 17 of FIG. 1 are sequentially arranged. Also, the dichroic mirror 51
A finder 55 is arranged on the optical path of the reflection direction so that it can be observed by the optometry e.

The reflected light flux from the fundus Er flips up the mirror 1.
The light beam focused by the focusing light source 1 of FIG. 1 is reflected by the dichroic mirror 51, the lens 52, and the cylindrical lens 53.
And enters the one-dimensional CCD 54. Further, the light flux from the observation light source 11 in FIG. 1 is reflected by the dichroic mirror 51, enters the finder 55, and is observed as a fundus image by the optometry e.

At the time of focusing, the focusing signal incident on the one-dimensional CCD 54 is calculated by the signal processor 21, and the focusing means 14 is driven by the driving means 13 based on this to perform focusing. Since the position of the focused light flux incident on the one-dimensional CCD 54 differs depending on the position of the focusing lens 14, the focus position is obtained in advance, and the fact that the focus position has been reached is determined by the finder 55.
The luminous flux is lit and displayed within the field of view.

It is also possible to drive the focusing lens 14 manually and display the focusing completion display in the viewfinder 55 instead of performing the focusing by the auto focus.

[0026]

As described above, the fundus camera according to the present invention does not use a movable part in the projection system and does not use a special optical member for separating a focused light beam, so that the structure is simple. Become. Further, regarding the light receiving optical system, it is possible to determine the position of the focused light flux in a focused state, and it is possible to effectively use the focusing lens to perform highly accurate focusing.

[Brief description of drawings]

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

FIG. 2 is a front view of a diaphragm.

FIG. 3 is an explanatory diagram of a positional relationship of light beams on a pupil plane.

FIG. 4 is a configuration diagram of a focused light beam projection system according to a second embodiment.

FIG. 5 is a configuration diagram of a focused light beam projection system according to a third embodiment.

FIG. 6 is a configuration diagram of an observation optical system of a fourth example.

[Explanation of Codes] 1, 34, 44 Focusing Light Source 4, 51 Dichroic Mirror 5 Photographing Light Source 11 Observation Light Source 12 Photographing Aperture 13 Driving Means 14 Focusing Lens 16 Jumping Mirror 17 Film 20 Television Camera 21 Signal Processor 22 TV monitor 31 Flat prism 53 Cylindrical lens 54 One-dimensional CCD

Claims (3)

[Claims] 1. A projection optical system for projecting a focused light flux onto a fundus of the eye to be examined from a predetermined position outside a photographing light flux on a pupil plane of the eye to be examined, and a fundus reflection light flux of the focused light flux is focused with a photographing diaphragm. In a fundus camera having a light receiving optical system for receiving light in a photoelectric sensor array via a lens, focusing is performed by a position of a light receiving light beam of the light receiving optical system in a direction connecting the predetermined position and the photographing light beam. Characteristic fundus camera. 2. The fundus camera according to claim 1, wherein the photoelectric sensor array is an image pickup device for picking up a fundus image. 3. The fundus camera according to claim 1, wherein focusing is determined on the photoelectric sensor array at a position of the focused light flux that differs depending on a position of the focusing lens.