JPH0263430A - Variable magnification type no pupil dilating fundus camera - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used for diagnosis by photographing the fundus of the eye,
In particular, the present invention relates to a variable magnification type non-mydriatic fundus camera that can vary the magnification of a photographing optical system.

[Conventional technology] Conventional no-rt! 1. A pupil-type bottom-bottom camera having a configuration as shown in FIG. 3 is known. That is, reference numeral 1 denotes an observation light source consisting of a tungsten lamp or the like, and the light emitted from this observation light source 1 is passed through a condenser lens 2 and a guichroic mirror 3 having the characteristic of transmitting visible light and reflecting infrared light.
Then, the ring-shaped opening 4a of the ring slit plate 4 is illuminated. The light emitted from the ring-shaped opening 4a is once imaged in the vicinity of the perforated mirror 6 via the relay lens 5, then reflected and travels to the left, and re-imaged in the vicinity of the cornea of the eye E by the objective lens 7. Then, the fundus Ef is illuminated. Then, the reflected light from the fundus Ef travels to the right, forms an image with the objective lens 7, passes through the hole of the perforated mirror 6, passes through the photographic lens 8 and flip-up mirror 9, and forms an image near the field lens 10. Further, the image is formed on the image receiving surface of the image pickup tube 13 via the half mirror 11 and the relay lens 12, and is displayed on the television monitor 14 as a bottom image Ea.

Also, behind the graphic mirror 3, there is a photographing light source 1.
5 and a condenser lens 16 are arranged. In the case of photography, this photography light source 15 emits light;
The light emitted from the eye passes through the condenser lens 16 and the guichroic mirror 3, and illuminates the fundus Ef of the eye E through the same optical path as the previous observation light. The light reflected by the fundus Ef passes through the objective lens 7 and the hole in the perforated mirror 6, and then is imaged and recorded by the photographic lens 8 on a film 17 placed on the optical path. In this case, the flip-up mirror 9 flips up in synchronization with a shutter (not shown) provided in front of the film 17, thereby switching the optical path.

Further, behind the half mirror 11, a small LED 19 is provided at a position conjugate with the film 17 via a projection lens 18. The light emitted from the LED 19 travels opposite to the observation light beam and reaches the fundus Ef of the eye E to be examined. Also, LED
19 is movable arbitrarily in a plane perpendicular to the optical axis as shown by the arrow, and the examiner can take a picture of the fundus E at any position by having the examinee focus on the image of this LED 19. However, this is what is called a floodlight type internal fixation device. This LED 19 always forms an image on the fundus Ef during photographing due to the focusing action of the photographic lens 8, so that very reliable fixation is possible.

Further, a part of the image of the LED 19 is reflected by the gicroic film applied to one surface of the field lens 10, and then reflected by the half mirror 11, and then reflected by the relay lens 12.
is guided to the projection tube 13 by. On the television monitor 14, this light is observed as a luminance Pa in combination with the fundus image Ea, and the fixation state of the eye E to be examined can be clearly recognized.

Non-mydriatic fundus cameras with this type of configuration have been widely used by general medical examinations and internists due to the safety and ease of imaging, but in recent years, the field of ophthalmology has also focused on treating glaucoma patients who cannot use mydriatic drugs. It is now used for diagnostic purposes. In this case, what is of most interest is the papilla of the fundus Ef, and for this reason, enlarged photography of the papilla is desired.

[Problems to be Solved by the Invention] In general, changing the magnification in a fundus camera is extremely meaningful for diagnosis. There are two ways to change the magnification, such as zooming the photographic lens 8 shown in Fig. 3 or changing the magnification of a turret. If this method is applied as is to a fundus camera, the movement range of the LED 19 on the fundus Ef becomes extremely narrow, making it difficult to freely photograph the fundus position. Furthermore, in order to enable variable magnification with the conventional configuration as described above, there is a problem in that the structure becomes extremely complicated. This is explained in Japanese Unexamined Patent Publication No. 54-147
No. 687, JP-A-54-141095, JP-A-54-
As explained in detail in Japanese Patent No. 139289, etc., this problem is caused by the fact that the observation device as well as the photographing optical system change the magnification at the same time.

[Object of the Invention] In order to improve the above-mentioned problems, the object of the present invention is to provide a system that allows photographing of the fundus position at any time by operating an internal fixation means independently of the variable magnification optical system of the photographing optical system. Furthermore, by providing the above-mentioned observation means independently of the variable magnification optical system, the configuration can be avoided from becoming complicated, and the above-mentioned state of internal fixation can be reliably observed using the observation means. The object of the present invention is to provide a non-mydriatic bottom-bottom camera.

[Summary of the Invention] The gist of the present invention for achieving the above-mentioned object is to provide an observation means for guiding invisible light from an observation light source into the eye to be examined to observe a fundus image, and a means for observing a fundus image by guiding invisible light from an observation light source into the eye to be examined. a photographing means for recording a fundus image by guiding the camera inside the eye; a variable magnification means disposed within the photographing means for varying the photographing magnification; and a fixation lamp that emits weak visible light without passing through the variable magnification means. A variable magnification type non-mydriatic fundus camera is characterized in that it is equipped with a projection type internal fixation means that shares at least a part of the optical system of the observation means and presents the image to the eye to be examined.

[Embodiments of the Invention] Hereinafter, a detailed explanation will be given based on the embodiments shown in FIGS. 1 and 2, and the same reference numerals as in FIG. 3 represent the same or equivalent members. . Further, since the configuration and operation of the illumination system below the perforated mirror 6 and the eye E to be examined are as described above with reference to FIG. 3, their explanation will be omitted here.

In Figure 1, the perforated mirror -6 and the flip-up mirror 9
A focusing lens 21 is disposed between the flip-up mirror 9 and a variable-magnification photographing lens 22a that is replaceably disposed behind the flip-up mirror 9. Further, an auxiliary lens 23 is inserted into the reflection side of the flip-up mirror 9, and between the image pickup/i2'13 and the TV monitor 14 is used to display arbitrary characters, symbols, etc. on the image surface of the TV monitor 14. A character synthesizer 24 is connected thereto. Furthermore, the photographing lens 22a
Several types of replacement photographic lenses 22b prepared for replacement are each provided with an electrical contact 25, and the magnification information of the photographic lens 22 in use is input to the character composition device 24. It looks like this.

Figure t52 is the fundus image Ea projected on the television monitor 14.
(a) is an image taken at a normal magnification, and (b) is an image taken at a higher magnification.

The fundus image Ea and the light spot Pa are as described in FIG. 3, but numbers A and B indicating the shooting angle of view are displayed in one corner of the screen. These numbers A and E are synthesized on the TV monitor 14 via the character compositing device 24 after receiving signals from the contact point 25 of the photographing lens 22. A is the angle of view during normal shooting, and B is the angle of view during shooting. This is a number that indicates the angle of view when the magnification is increased.

In FIG. 2(b), rectangular optotypes C1 to C4 indicating the fundus imaging range at the imaging magnification are also displayed, and these are also synthesized by the character compositing device 24, and are included in the fundus image Ea. The shooting range is displayed from four directions.

From this display, the examiner can check what angle of view and which body parts are currently available for imaging.
Photography can be easily performed. In order to display the optotypes C1 to C4 as necessary, something like a liquid crystal shutter may be used, but a parallel plane plate placed on the finder focal plane may also be etched in advance. .

What should be noted here is that when the internal fixation means is operated through the variable magnification system as in the conventional case, the fundus photographing range shown in FIG.
This means that the light spot Pa of image No. 9 is located outside the photographing range. This indicates that the LED 19 is not observed in the subject's eye E as well, making it impossible to perform magnified photography centered on the papilla as shown in FIG. 2(b). Against this.

In this embodiment, the internal fixation means operates regardless of the magnification change of the photographing optical system, so that photographing is possible as shown in FIG. 2(b). Furthermore, if an observation device is provided independently for variable magnification, the light spot Pa can also be checked on the television monitor 14 at all times.

Note that it is also possible to have the focusing lens 21 have a relay lens function to form a real image, and to have the interchangeable photographing lens 22b each have a relay lens function, so that the magnification can be changed by attaching and replacing the relay lens system. be. Further, it is also possible to provide an automatic switching means that uses the electrical contact 25 provided on the photographic lens 22 to automatically switch the amount of photographing light according to the change in magnification of the photographic optical system. It goes without saying that the photographic lens 22 may be a zoom lens, but its magnification information may be input to the character composition device 24 using a slide resistor or the like.

[Effects of the Invention] As explained above, in the variable magnification type Mlli bottom limit camera according to the present invention, the internal fixation means acts independently regardless of the variable magnification photographing device, so that it can be used normally at any magnification. This has the effect of making it possible to freely photograph the position of the fundus.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of a variable magnification type non-mydriatic fundus camera according to the present invention, and Figure 1 is a configuration diagram thereof, and Figure 2 (
a) and (b) are front views of a television monitor screen as the magnification is changed, and FIG. 3 is a configuration diagram of a conventional fundus camera. Reference numeral 1 is an observation light source, 3 is a gicroic mirror, 4 is a ring slit plate, 6 is a perforated mirror, 7 is an objective lens,
9 is a flip-up mirror 11 is a reflection mirror, 13 is an image pickup tube,
14 is a television monitor, 15 is a photographing light source, 17 is a film, 18 is a projection lens, 19 is an LED, 21 is a focusing lens, 22 is a photographic lens, 23 is an auxiliary lens, 2
4 is character synthesis equipment, and 25 is an electrical contact. Patent applicant Canon Co., Ltd. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. Observation means for guiding invisible light from an observation light source into the subject's eye to observe a fundus image, and photographing means for guiding visible light from a photographing light source into the subject's eye to record the fundus image. and a variable magnification means which is located within the photographing means and makes the photographing magnification variable, and an optical system of at least a part of the observation means which allows a fixation lamp that emits weak visible light to be transmitted without going through the variable magnification means. 1. A variable magnification non-mydriatic fundus camera, characterized in that it is equipped with a projection-type internal fixation means that shares the image with the eye to be examined. 2. The variable magnification type non-mydriatic fundus camera according to claim 1, wherein the variable magnification means is provided outside the optical path of the observation means.