JP3165716B2 - Fundus camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera provided with an automatic focusing device or an automatic alignment device.

[0002]

2. Description of the Related Art Conventionally, in a fundus camera provided with an automatic focusing device, a bright spot for detecting a working distance and a fixation target are displayed on an imaging means in addition to a projection index for focusing.

[0003]

However, in the above-mentioned prior art, there is a disadvantage that the accuracy of the automatic focusing is reduced due to a light beam other than the projection target for focusing in performing the automatic focusing.

When automatic alignment is performed at a position where a fundus image is formed by using a luminescent spot for detecting a working distance at which a corneal reflection image is formed, an automatic alignment is performed for a projection target for focusing or a fixation target. There is a disadvantage that the accuracy of alignment is reduced.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fundus camera which has solved the above-mentioned disadvantages. The gist of the present invention is to project a predetermined index light beam onto an eye to be examined and to project other light beams. Imaging means for detecting a reflected image of the projected light flux from the eye to be examined together with a fundus image; means for detecting the state of the projected predetermined index light flux on the imaging means; and the detection means operating In this case, it is characterized by having a means for dimming at least a part of the other light flux.

[0006]

The light unnecessary for automatic focusing and automatic alignment is reduced (including light intensity reduction, light source extinguishing, and light shielding).

[0007]

FIG. 1 shows an embodiment relating to automatic focusing of a fundus camera. In FIG. 1, reference numeral 1 denotes a tungsten lamp as an observation light source, and light emitted from the tungsten lamp 1 is a ring slit 2 and illumination. To the aperture mirror 7 via the lens 6 for use. The light incident on AnaAkira mirror 7 in the observation optical system passes through the through further AnaAkira mirror 7 by irradiating the original optical path of the fundus E _f of the eye E is reflected in the direction of the eye E by AnaAkira mirror 7 However, the objective lens 8 is disposed between the perforated mirror 7 and the eye E to be inspected, and the focus lens 2 is arranged behind the perforated mirror 7 along the optical axis.
2. A projection lens 10, a flip-up mirror 11, and a film for photographing 12 are sequentially arranged. Further, 3 denotes a light source for projecting an index for focusing, 4 projected index prism with the slit is projected onto the fundus E _f by the half mirror 5. 9 is a light source for working distance detection is projected through the objective lens 8 onto the fundus E _f. 13 is a fixation target,
It is projected onto the fundus E _f by the half mirror 14. 15 denotes an image camera for imaging the fundus E _f. The signal output from the imaging camera 15 is sent to the monitor 16 and displayed. Reference numeral 17 in the monitor 16 denotes an index reflection image for focusing, reference numeral 18 denotes a luminescent spot for detecting a working distance, and reference numeral 19 denotes a luminescent spot of a fixation target.

FIG. 2 shows the details of the automatic focusing device. Reference numeral 20 denotes a focus detection controller. When detecting the in-focus state using the video signal from the imaging camera 15, the focus detection controller 20 dims one or both of the light source 9 for working distance detection and the fixation target 13 (light intensity reduction, (Including light source turning off and light blocking), and two scanning lines m and n passing through each of the two focus target reflection images with respect to the fundus image displayed on the monitor 16.
Read the second video signal. The focus target reflection image in the m-th and n-th video signals is recognized as a signal intensity, and a signal for focus adjustment is sent to the focus drive unit 21 so that the horizontal position of each signal is equal. Feed and focus the fundus image.

FIG. 3 shows an embodiment relating to automatic alignment of the fundus camera. Arrangement of the optical system is the same as FIG. 1, the signal output from the photographing camera 15 for detecting the fundus E _f is displayed is sent to the monitor 16.

FIG. 4 shows the details of the automatic alignment apparatus. 23 is an alignment detection controller. When detecting the distance between the eye E and the objective lens 8, the alignment detection controller 23 dims one or both of the light source 3 for the projection target for focusing and the fixation target 13 (light intensity reduction, light source (Including light-off and light-shielding), and the scanning line m passing through two bright spots for detecting the working distance with respect to the fundus image displayed on the monitor 16
Read the second video signal. Then, a signal for performing the alignment adjustment is sent to the alignment driving unit 24 so that the signal level of the luminescent spot for detecting the working distance in the m-th video signal reaches the set level. Perform distance alignment.

In the above example, the video signal is read using a scanning line passing through the two bright points for detecting the working distance.
This may use a scanning line passing through one bright point for detecting the working distance. Also, whether or not the alignment has been performed is determined based on the signal level of the video signal. However, it may be determined based on the output time width of the signal of the bright spot portion for detecting the working distance.

[0012]

As described above, according to the present invention, the accuracy of automatic focusing and automatic alignment can be improved in the fundus camera.

[Brief description of the drawings]

FIG. 1 is a diagram of a first embodiment of the present invention;

FIG. 2 is a detailed view of an automatic focusing device,

FIG. 3 is a diagram of a second embodiment of the present invention;

FIG. 4 is a detailed view of an automatic alignment device.

[Explanation of symbols]

 3, 17 Light source for focus projection index 9, 18 Light source for working distance detection 13, 19 Fixation target 15 Imaging camera 20 Focus detection controller 21 Focus drive unit 22 Focus lens 23 Alignment detection controller 24 Alignment Drive part

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-61-37131 (JP, A) JP-A-60-253431 (JP, A) JP-A-62-281922 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) A61B 3/00-3/16

Claims (3)

(57) [Claims] 1. A method for focusing or aligning an eye to be examined.
Means for projecting a target luminous flux for the
Means for projecting a different second light flux from the light beam, and imaging means for imaging <br/> the reflected image due to the subject's eye of the index <br/> light flux with a fundus image of the eye, obtained by the image pickup means Included in the video signal
Focus based on the signal of the reflected image of the index light beam
Detecting means for detecting a state or an alignment state ;
Unnecessary light other than the index light flux is reduced by reducing the second light flux when the detection means is operated and the imaging means performs imaging.
A fundus camera comprising a control unit for reducing the amount of light. 2. The method according to claim 1, wherein the index light beam is used for focusing.
The second light flux is a light flux for alignment detection and a fixation target light flux.
The fundus turtle according to claim 1, which is at least one of a light beam.
La. 3. The method according to claim 2, wherein the index beam is for alignment.
The second light beam is a light beam for focusing and a light beam for a fixation target.
The fundus camera according to claim 1, which is at least one of the following.