JP2736780B2 - Fundus camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fundus camera, and more particularly, to a fundus camera having a fixation target for determining a viewing direction of an eye to be inspected.

[Conventional technology]

A fixation target is provided at the conjugate position of the fundus of the observation system.
Japanese Patent Application Laid-Open No. 60-60831), a method in which a plurality of fixation targets are provided at a fundus conjugate position outside the optical path of an illumination system (Japanese Patent Application Laid-Open No. 62-90133), A device in which two fixation targets are switched (JP-A-60-60831) is known.

[Problems to be solved by the invention]

In a group examination using a non-mydriatic retinal camera, a technique for fixing a fixed target at that position because the imaging region is constant is known.

On the other hand, as a fundus camera, a so-called variable-magnification fundus camera with a variable photographing magnification is known, and is usually used to magnify and photograph a nipple at a low angle of view.

However, when the former technique is applied to the latter fundus camera, since the shooting area differs depending on the shooting magnification, the fixation target setting position selected under certain shooting conditions must be changed when shooting at another magnification. There's a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fundus camera in which a fixation target is automatically selected and moved to a predetermined position in accordance with a change in a photographing magnification.

[Means for solving the problem]

In order to achieve the above object, in the fundus camera of the present invention, the fixation target has a low angle of view and a high angle of view in conjunction with the insertion and removal of the variable power lens into and from the fixation target projection system. It was configured to be displaced between. In addition, one fixation target can be moved as a movable target between a low-angle fixation target position and a high-angle fixation target in conjunction with insertion and removal of the variable power lens into and out of the fixation target projection system. It was constituted so that it might become.

Further, by operating the position detection microswitches provided on the left and right of the retinal camera frame, the left eye fixation target and the right eye fixation target are respectively selected for each elevation angle. Configured.

Furthermore, the motorized XY stage is moved in conjunction with the insertion / removal of the variable power lens into / from the fixation target projection system, so that the fixation target for the left and right eyes and the elevation angle (45 °, 20 °) can be switched. It can be configured to be performed automatically.

(Operation)

In the fundus camera configured as described above, the selection of the eye to be inspected is performed by the operation of the position detection microswitches provided on the left and right of the retinal camera mount, and the change of the imaging magnification is provided on the retinal camera mount. The photographing angle of view switch is operated by operating the switch, and in response to the operation of the switch, the variable magnification lens is inserted into and removed from the fixation target photographing system, and the position of the fixation target corresponding to each angle of view is changed. Selected automatically.

〔Example〕

FIGS. 1 (a) and 1 (b) show an optical system of a fundus camera to which the present invention is applied, and an illumination system A for illuminating a fundus of a subject's eye, and for observing or photographing the eye system of the subject's eye. , A focusing index projection system C for detecting the in-focus state of the subject's eye, and a fixation target projection system D for projecting a light beam from the fixation target onto the fundus of the subject's eye. .

Illumination System A The illumination system A has an observation light source 1. A light beam emitted from the observation light source 1 passes through a condenser lens 2 and an infrared filter 3 that cuts visible light and transmits only infrared light,
The ring-shaped diaphragm 5 reflected by the oblique half mirror 4 is illuminated. The illumination system A is provided with a light source 6 for photographing, and the light from the light source 6 for photographing is supplied to a condenser lens 7.
The ring-shaped diaphragm 5 is illuminated by passing through the oblique half mirror 4.

The light transmitted through the ring-shaped aperture 5 passes through the relay lens 36, the oblique mirror 37, and the relay lens 8, and passes through the objective lens 10
Reaches the perforated mirror 9 obliquely provided on the optical axis, and is reflected by the perforated mirror 9 in the direction of the objective lens 10 to illuminate the fundus of the eye 11 through the objective lens 10.

Observation imaging system B The light beam reflected by the fundus of the eye 11 to be examined advances along the optical axis of the objective lens 10 and the aperture of the objective lens that has passed through the aperture of the perforated mirror 9, and is focused on this optical axis. Lens 12
2 (a) is formed on the surface of the filter 14 by the imaging lens 13. This is a fundus image when the fixation target for the left eye is turned on and the subject is collimated with the fixation target because the left eye is photographed by the fundus camera with a photographing angle of view of 45 °. The vicinity of the right side is shown as a fundus image with a high angle of view (45 °).

A mirror 15 is disposed in front of the film 14 so as to be retractable, and is arranged at a position indicated by a solid line at the time of observation and retracted to a position indicated by a broken line at the time of photographing. Therefore, at the time of observation, the light beam from the fundus is reflected upward by the mirror 15 and a fundus image with a high angle of view is formed on the field lens 16. The high-angle fundus image formed on the field lens 16 is provided by an oblique mirror 17 and a relay lens 18 for an infrared light imaging tube 19.
Is formed on the photocathode. The electric signal from the imaging tube 19 is input to the monitor television 20, and a high-angle fundus image is displayed on the screen of the monitor television 20 as a visible image.

To take a picture at the position where the nipple comes to the center of the photographic screen in order to enlarge the nipple, use the zoom lens 31 and the imaging lens 13
At the position on the optical axis behind the The one corresponding to the photographed image at this time is a fundus image with a low angle of view (20 °) shown in FIG. 2 (b).

Focusing Index Imaging System C The focusing index imaging system C has a slit indexing plate 23 for focusing. As shown in FIG. 3, the slit index plate 23 is provided with a slit-shaped index 23a,
A deflection angle prism 24 made of 4b is arranged in close contact.
The light beam from the infrared light source 21 illuminates the slit index plate 23 by the condenser lens 22, and the light beam transmitted through the slit index 23a is split into two light beams by the deflection prisms 24a and 24b.

The two light beams reach the mirror 28a disposed behind the perforated mirror via the relay lens 25 and the oblique mirror 27. The mirror 28a has two reflecting portions for separately reflecting the two light beams separated by the deflection prisms 24a and 24b, and these light beams are reflected by the mirror 28a and pass through the opening of the perforated mirror 9. A slit index image is formed on the fundus of the eye by the objective lens. The slit index image formed on the fundus of the subject is observed on the television monitor 20 so as to overlap the fundus image.

Infrared light source 21, condenser lens 22, slit index plate
23 and the deflection prism 24 are used for the focusing lens 12 for observation and photography B.
And is configured to be movable in the optical axis direction.
Therefore, by moving the focusing lens 12 to a position where the slit index 23a is focused on the fundus of the eye 11 to be inspected, that is, a position where the image of the slit index 23a is observed as a unit without being separated on the fundus. Focusing on the fundus such as observation and photography can be performed.

Fixation target projection system D Between the slit index plate 23 and the relay lens 25, as shown in FIG. 1B, a wavelength selection mirror 28 for transmitting infrared light and reflecting visible light is obliquely provided. Have been. LED fixation targets 29a, 29b and 30a, 30b having a green wavelength characteristic at positions symmetrical with respect to the optical axis on the reflection optical axis of this mirror 28 are located at positions conjugate with the slit-like index 23a of the slit index plate 23. Each is arranged. When the variable power lens 31 is not at a position on the optical axis of the objective lens 10, these fixation targets are a set of fixation targets 29a, 29.
When b is selected as a fixation target for a high angle of view (45 °) and inserted at a position on the optical axis, the other set 30a, 30b has a low angle of view (20 °)
It is configured to be selected as a fixation target for use.

The light flux from the fixation target 29a, 29b or the fixation target 30a, 30b is reflected by the wavelength selection mirror 28, passes through the optical system described in the above-described focusing target projection system C, and is projected onto the fundus of the eye to be examined. .

This fixation target 29a, 29b or 30a, 30b is a fixation target for the left eye and the right eye, respectively.When the fundus camera housing is moved rightward as viewed from the examiner to photograph the left eye, Only the fixation target 29a or 30a lights up in conjunction with it, and similarly when it moves to the left to photograph the right eye, it also links with the fixation target 29b or 30b.
Only one is configured to light.

That is, as shown in FIG. 4, the power supply 100 is connected to the input terminal of the angle-of-view switch l,
Are connected to the input terminals of the left and right eye changeover switches m and n, respectively. The fixation target light sources 29a, 30a, 29b, and 30b for the left and right eye low angle of view, the left eye high angle of view, the right eye high angle of view, and the right eye low angle of view are provided at the output terminals of the left and right eye changeover switches m and n, respectively. Are connected, and these other terminals are connected to the light source 100. In this circuit, the angle-of-view switch 1 is switched in conjunction with the insertion and removal of the variable power lens 31 from the optical axis, and the left and right eye switches m and n are switched in conjunction with the switching of the gantry to the left and right eyes.

In this manner, by inserting and removing the variable power lens 31 at a position on the optical axis of the objective lens, a set of fixation targets for a low angle of view (20 °) can be obtained.
A set of fixation targets 30a, 30b for 29a, 29b or a high angle of view (45 °) is selected, and the left eye is moved by moving the fundus camera housing to the right or left with respect to the selected set of fixation targets. Alternatively, the right eye can be selected as the eye to be examined. Therefore, by collimating the selected subject's eye to the corresponding fixation target, the subject's collimation, that is, the direction of the line of sight is fixed, and it is possible to easily photograph the appropriate portion of the selected subject's eye at different magnifications.

Another Embodiment of Fixation Target Projection System D Another embodiment of a fixation target projection system having a movable fixation target is shown in FIGS. 5 (a), (b), (c) and (d).

FIG. 5 (a) is an optical diagram similar to FIG. 1 (a).
A half mirror 32 is obliquely provided between the focusing lens 13 and a variable power lens 31 which is removably inserted at a position rearward on the optical axis. It is configured such that a reflection image of the fixation target 33 disposed at a position in front of the half mirror 32 is projected on the fundus of the subject through the imaging lens 13, the focusing lens 12, and the objective lens 10. .

FIG. 5B shows four possible target positions of the movable fixation target 33. Two positions 40a and 40b symmetrical to the reference numeral 33 correspond to fixation target positions when the variable power lens 31 is removed from the optical path and a fundus image with a high angle of view (45 °) is taken, and the left eye and the right eye respectively. Is a position for selecting as the eye to be examined. Similarly, the sign
Two positions 41a and 41b symmetrical with respect to 33 correspond to fixation target positions when a variable-magnification lens 31 is inserted into the optical path and a fundus image with a low angle of view (20 °) is taken. Is a position for selecting as the eye to be examined.

FIGS. 5C and 5D show a moving mechanism of the movable fixation target 33. FIG. The fixation target 33 is fixed by a click mechanism including a ball plunger 42 and a coil spring 43 at its moving position, that is, at each of a high angle of view (45 °) position and a low angle of view (20 °) position of the left and right eyes. Locked. When a magnified image of the nipple is taken at a position where the nipple comes to the center of the angle of view by selecting a low angle of view position, the nipple position often varies significantly due to individual differences. In such a case, the handle 110 may be turned 90 degrees to release the click locking mechanism, and the handle 112 may be used to finely adjust the fixation target position.

In addition, a motorized XY stage can be adopted to automatically switch between the left and right eyes and a high angle of view (45 °) and a low angle of view (20 °) and to lock the fixation target at the switching position. It is possible.

〔The invention's effect〕

According to the present invention having the above-described configuration, when the variable power lens is inserted into and removed from the optical axis in order to change the photographing lens, the fixation target is set at a position suitable for each magnification in conjunction with this. Has the advantage that

[Brief description of the drawings]

1A is an optical diagram of a fundus camera according to an embodiment of the present invention, FIG. 1B is an optical diagram viewed in the direction of arrow I in FIG. 1A, and FIG. 2A. FIG. 2B is a fundus image of a low angle of view (20 °) photographing, FIG. 3B is a perspective view showing a slit index plate for focusing, FIG. FIG. 4 is a fixation target lighting circuit diagram, FIG. 5 (a) is an optical diagram of a fundus camera according to another embodiment, FIG.
FIG. 5C is a cross-sectional view showing a moving mechanism of the movable fixation target, and FIG. 5D is a cross-sectional view taken along line 5 (d) of FIG. 5C. A: illumination system, B: observation and photography system, C: focusing target projection system, D: fixation target projection system, 10: objective lens, 13: imaging lens, 14: film, 23 …… Slit index plate for focusing, 23a …… Slit-shaped index, 29a, 29b …… Fixation target for high angle of view, 30a, 30b …… Fixation target for low angle of view, 31 …… 32 …… Half mirror, 33… Movable fixation target, 34 …… Wave washer, 38 …… Coil spring, 39 …… Steel ball, 40a, 40b …… Fixation position click hole for high angle of view, 41a, 41b … Click hole for fixation position for low angle of view, 42… Ball plunger, 43… Coil spring, l …… Angle switch, m… Left and right eye switch.

Claims (3)

(57) [Claims] 1. A variable power lens disposed removably in an optical path of a photographing optical system for changing a photographing magnification, and a fixation target for guiding a line of sight of an eye to be examined is projected toward a fundus of the eye to be examined. A fundus camera provided with a fixation target projection optical system, wherein a projection position of the fixation target is changed in conjunction with insertion / removal of the variable power lens. 2. An illumination system for illuminating the fundus of the eye to be examined through an objective lens arranged opposite to the eye to be examined, a photographing system for photographing the fundus of the eye to be examined through the objective lens, and changing a photographing magnification of the photographing system. Therefore, a fundus camera including a variable power lens disposed removably in the optical path of the photographing system and a fixation target projection system for projecting a fixation target to the fundus of the eye to be examined through the objective lens. A fundus camera, wherein a projection position of the fixation target is changed in conjunction with insertion / removal. 3. The fundus camera according to claim 1, wherein the change of the projection position of the fixation target is performed by moving the fixation target.