JPH0595902A - Eyeground camera - Google Patents

Abstract

PURPOSE:To provide an eyeground camera which enables accurate adjustment of focus with better operability. CONSTITUTION:An auxiliary lens 8 is retracted from an optical path with a changeover switch 20 and when a switching is made from the state of observing the anterior ocular segment to the state of observing the eyegrounds, time is counted with the passage of a specified time with a timer 23 by an input of the changeover switch 20. The range of the time is regarded as a period during which a fixation environment where a target 25 is recognized visually changes to forbid the operation of adjusting focus automatically and after the time passed. automatic adjustment of focus is accomlished.

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 ophthalmology clinics, mass examinations, etc., which has an automatic focus adjusting means.

[0002]

2. Description of the Related Art Conventionally, as a fundus camera having an automatic focus adjusting means, it is known that a focus adjusting operation is prohibited during an alignment operation as described in Japanese Patent Laid-Open No. 57-1322. A fundus camera configured to start a focus adjusting operation according to a switch input is also known.

[0003]

Generally, in the fundus camera, a fixation target (internal fixation target or external fixation target) is provided. However, from the anterior ocular segment surface observation state (during alignment operation) of the eye to be examined. When switching to the observation state of the fundus of the eye to be inspected, the environment in which the fixation target is visually recognized changes greatly and the diopter of the eye to be inspected becomes unstable.

Further, if the focus adjustment operation start switch input is made within the period of the unstable state, there is a problem that accurate focus adjustment is not performed and the timing of photographing may be missed.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fundus camera which solves the above-mentioned problems of the prior art, and the gist thereof is to automatically adjust the focus on the fixation target and the fundus of the eye to be examined. In the fundus camera equipped with an automatic focus adjusting means for performing, and a means for selectively observing the fundus of the eye to be examined and the anterior ocular surface of the eye to be inspected, from the observation state of the anterior eye surface of the eye to the observation state of the eye fundus of the eye. Switching means, a time counting means for counting a predetermined time from the time when the switching is detected, and a focus adjusting operation of the automatic focus adjusting means when the elapse of the predetermined time is detected by the time counting means. It has a control means for starting.

[0006]

[Function] The change from the anterior segment observation state to the fundus observation state is detected, the elapse of a predetermined time from that point is detected by a timer, the automatic focus adjustment operation within that time is prohibited, and the automatic focus is performed after the elapse of the time. Perform adjustment operation.

[0007]

1 is a drawing showing an embodiment of the present invention. In the figure, 1 is a light source for illuminating the fundus, 2 is a ring slit having a ring-shaped opening that limits the incident area of a light beam on the pupil surface of the eye to be examined, 3 and 4 are lenses, and 5 is a hole having an opening near the optical axis. A clear mirror, 6 is an objective lens, 7 is a light source for illuminating the anterior segment of the eye, 8 is an auxiliary lens that is detachably arranged in the optical path for observing or photographing the anterior segment of the eye, and 9 is for focus adjustment.
A focus lens that is movable in the optical axis direction, 1
Reference numeral 0 is a photographing lens, 11 is a flip-up mirror that is retracted out of the optical path at the time of photographing, 12 is an image pickup means for picking up an anterior eye part and fundus image, and detecting a focus index, 13 is a film box, and 14 is a mirror surface at the tip. Yes A bar mirror that retracts outside the optical path during shooting, 15 is a lens, 16 is a slit as a focus index, 17 is a split prism, 18 is a light source for focus adjustment, 19 is a control box, and 20 is the anterior surface of the object to be imaged. A changeover switch for changing over to a bottom surface or a fundus of the eye, 21 is a photographing switch, and 22 is an imaging means
2 is a monitor for displaying the imaged image, 23 is a timer which is a time counting means, 24 is a split image projecting means, 25 is an internal fixation target, and 26 is a beam splitter.

With the auxiliary lens 8 inserted in the optical path, the anterior ocular segment image of the eye to be examined illuminated by the light beam emitted from the light source 7 is the aperture of the objective lens 6, the auxiliary lens 8 and the perforated mirror 5. Section, focus lens 9, photographing lens 10
The optical path is bent downward by the flip-up mirror 11 and an image is formed on the image pickup means 12. The anterior ocular segment image formed on the imaging means 12 is converted into a video signal, passes through the control box 19, and is displayed on the monitor 22.

The examiner observes the image displayed on the monitor 22, and the contrast of the image becomes clear, and the main body is adjusted by a positioning means (not shown) so that the center of the pupil of the eye to be examined coincides with the center of the screen. And coarse alignment of the distance between the eye to be inspected and the vertical and horizontal directions of the main body.

When the rough alignment of the eye to be inspected and the main body is completed by the above operation, the examiner presses the changeover switch 20. Note that the alignment fine adjustment can be performed so that flare and ghost are not mixed into the fundus image while observing the fundus image of the eye to be examined after the input of the changeover switch 20.

The control box 19 receives an input from the switch 20, turns off the light source 7, retracts the auxiliary lens 8 out of the optical path, and turns on the light sources 1 and 18.
The device switches to the fundus observation state.

The light beam emitted from the light source 1 passes through the ring-shaped opening of the ring slit 2, the lens 3 and the lens 4, is reflected by the perforated mirror 5 and passes through the objective lens 6, and from the peripheral part of the eye E _{p to} be examined, Illuminate the fundus E _f . The fundus image thus illuminated includes the pupil E _P , the objective lens 6, and the perforated mirror 5.
Through the focus lens 9 and the taking lens 10 in the hole of the, and is reflected by the flip-up mirror 11, and the imaging means 12
Image on top. The fundus image on the image pickup means 12 is converted into a video signal and is displayed on the monitor 22 through the control box 19.

The light flux emitted from the light source 18 is reflected by the prism 17
The slit 16 is illuminated through the lens 15, passes through the lens 15, is reflected by the mirror portion of the rod mirror 14, passes through the lens 4, is reflected by the perforated mirror 5, and passes through the objective lens 6 to the eye E from the eye E _p to be inspected. Upon incidence, a slit image is formed on the fundus E _f .

The slit image formed on the fundus E _f passes through the focus lens 9 and the taking lens 10 in the hole of the eye E _{p to} be examined, the objective lens 6 and the perforated mirror 5, and is reflected by the flip-up mirror 11. Then, it is re-imaged on the image pickup means 12.

Bar mirror 14, lens 15, slit 1
6, the prism 17, and the light source 18 are integrated to form a split image projection means 24, which moves along the optical axis 01 in conjunction with the focus lens 9.

When the diopter of the eye to be inspected and the diopter of the main body are coincident with each other, the slit image displayed on the monitor 22 is coincident with the upper and lower slit images as shown in FIG. E _f is adjusted so as to be conjugate with the film surface 13. When the diopter of the eye to be inspected and the diopter of the main body are different from each other, the monitor 22 displays an image in which the upper and lower slit images are laterally displaced as shown in FIG. The control box 19 detects the positional deviation of the slit image from the video signal, adjusts the focus lens 9 and the split image projection means 24 according to the detected deviation amount, and automatically adjusts the focus of the main body optical system with respect to the fundus of the eye to be examined. To do.

Now, at the same time when the examiner switches from the anterior ocular segment observing state to the fundus oculi observing state by the changeover switch 20, the timer 23 starts to operate for a predetermined time (internal fixation target 2).
A signal is sent to the control box 19 after a lapse of time (when the fixation environment for visually recognizing 5 changes and the diopter of the eye to be inspected is unstable). Control box 19
Receives this signal and starts the automatic focus adjustment operation.
After the changeover switch 20 is input, the automatic focus adjustment operation continues even if the alignment fine adjustment is performed to remove flare or the like in the fundus image observation state, but the auxiliary lens 8 causes the optical path to observe the anterior segment image again. If it is inserted inside, the automatic focus adjustment operation is prohibited.

As described above, when the alignment of the eye to be inspected with the main body and the focusing of the fundus of the eye to be inspected are completed, the examiner presses the photographing switch 21. Then, the rod mirror 14 and the flip-up mirror 11 are retracted out of the optical path, the image of the fundus oculi E _f illuminated by the light source 1 is recorded on the film 13, and the photographing is completed.

In the above embodiment, the automatic focus adjusting operation is started after a predetermined time has elapsed from the input to the switch 20 for switching from the anterior ocular segment observation state to the fundus image observation state so as to retract the auxiliary lens 8 from the optical path. However, the present invention can also be applied to a fundus camera of a system in which an anterior ocular segment observation state and a fundus image observation state are switched by changing the optical axis direction distance between the main body and the eye to be inspected. That is, in this case, means for detecting the front-back position of the main body may be provided, and the automatic focus adjustment operation may be started after a predetermined time elapses from the time when the main body approaches the eye to be inspected from the predetermined position.

In the above embodiment, the slit image is projected on the fundus of the eye to be inspected, and the amount of deviation is detected by the image pickup means to automatically focus the image. Alternatively, the fundus camera may directly detect the resolving power and perform focusing so that the contrast and the resolving power are maximized. Further, it goes without saying that the present invention can be applied to a fundus camera having separate focus detection means and observation means.

The fixation target is not limited to the internal fixation target, but may be a so-called external fixation target.

The above-described present invention is particularly effective in a control system apparatus that does not perform an automatic focus adjustment operation after focusing once.

That is, the human eye has a phenomenon called involuntary eye movement, and the diopter is constantly changing. In order to focus on the fundus that continues to change, if the automatic focus adjustment operation is continued, the shooting switch is not received during the focusing operation, or even if it is accepted, the input between the shooting switch and the actual shooting Since there is a time difference between the two, the shooting timing is missed. Therefore, once the focusing operation is completed, it is easier to use the apparatus if the automatic focus adjustment operation such as the detection of the focus state is not performed so that the input from the photographing switch can be responded immediately.

In the apparatus of such a system, it is necessary to start and end the automatic focus adjustment when the adjustment state of the eye to be examined becomes stable.

Therefore, the automatic focusing may be started after detecting that the eye to be examined is in the stable adjustment state, but the time required for the eye to be brought into the stable adjustment state varies depending on the individual. Since it is considered that there is no great difference, it is sufficiently effective to set the time as the predetermined time in advance.

[0026]

As described above, according to the present invention, operability can be improved and accurate focus adjustment can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram of a focus index image when the fundus of the eye to be examined is in focus.

FIG. 3 is a diagram of a focus index image when the fundus of the eye to be examined is out of focus.

[Explanation of symbols]

 8 Auxiliary lens 9 Focus lens 12 Image sensor 13 Film box 16 Slit 17 Split prism 18 Focus adjustment light source 19 Control box 20 Changeover switch 21 Shooting switch 22 Monitor 23 Timer 24 Split image projection means 25 Internal fixation target

Claims (1)

[Claims] 1. A fundus provided with a fixation target, an automatic focus adjusting means for automatically adjusting the focus on the fundus of the eye to be inspected, and means for selectively observing the fundus of the eye to be inspected and the anterior ocular surface of the eye to be inspected. In the camera, means for detecting switching from the observation state of the anterior ocular surface of the subject's eye to the observation state of the fundus of the subject's eye, time counting means for counting a predetermined time from the time when the switching is detected, and the time counting means The fundus camera is characterized by further comprising control means for starting the focus adjusting operation of the automatic focus adjusting means when the passage of the predetermined time is detected.