JPH049137A - Eye ground camera - Google Patents

Abstract

PURPOSE:To obtain an eye ground camera compact as a whole by arranging a focusing detection system so that a target luminous flux is projected to an eye ground through a wavelength-dividing reflection mirror and the reflected light is received through the wavelength dividing reflection mirror. CONSTITUTION:Parallel luminous flux is made to irradiate a target mask 56 with an infrared rays source 50 and a condenser lens 52. The focused infrared luminous flux emitted from the target mask 56 reaches an eye ground Ed of an eye to be inspected through a lens 58, a 2-hole stop 62, an infrared half mirror 64, a long pass filter 64, relay lenses 8 and 9, a periphery of a bored mirror 10 and an objective lens 11. The reflected luminous flux of the focused infrared luminous flux at the eye ground Eb of the eye to be inspected reaches a detector 82 through the objective lens 11, a dichroic mirror 10a, relay lenses 9 and 8, the long pass filter 64, the infrared half mirror 64 and a lens 80 to form as image of the focused infrared luminous flux at the eye ground Eb of the eye to be inspected on the detector 82 again.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a fundus camera equipped with an observation and photography system for observing and photographing the fundus of an eye to be examined, and a focus detection system for detecting the focus state. Regarding improvements.

(Prior art) As a conventional fundus camera, the focus state of the eye to be examined is detected by irradiating the eye with a focusing light beam through a mirror installed diagonally in the observation and photographing system. was.

(Problems to be Solved by the Present Invention) However, in conventional fundus cameras, a mirror or the like is provided to align the optical axis of the focusing light beam with the optical axis of the observation and photographing system in front of the subject's eye. Due to the presence of optical components,
The distance from the subject's eye to the film surface or the observing examiner becomes longer, and the entire fundus camera becomes larger, creating the problem that it occupies a considerable amount of space when placed in a treatment room of a hospital or the like.

The present invention has been made in view of these conventional problems, and includes a mirror for aligning the optical axis of the focusing light beam with the optical axis of the observation and photography system in front of the subject's eye. The fundus is made compact as a whole by being substantially integrated with a perforated mirror for reflecting the light source light beam for use, and by aligning the optical axis of the focusing light beam and the optical axis of the light source light beam for observation and photography to a large extent. The purpose is to provide cameras.

(Structure of the Invention) The present invention includes an illumination system for illuminating the fundus of an eye to be examined with light in a first wavelength range via a perforated mirror, and light reflected from the fundus of the eye to be examined illuminated by the illumination system. an observation and photographing system for observing and photographing the formed fundus image through the hole of the perforated mirror; and a system for focusing on the fundus of the subject's eye with light in a second wavelength range different from the first wavelength range. In a fundus camera having a focus detection system for projecting an index light flux and detecting a focus state by receiving reflected light of the projected index light flux, the hole of the perforated mirror is provided with the first wavelength range. is provided with an optical member that transmits light in the second wavelength range and reflects light in the second wavelength range, and the focus detection system projects the index light beam onto the fundus via a wavelength-dividing reflector, and transmits the reflected light from the fundus in the wavelength range specified above. This fundus camera is characterized in that it is configured to receive light through a split reflector.

(Function) According to the present invention, the light source light beam for observation and photographing and the focusing light beam coaxially enter the perforated mirror, and the focusing light beam reflected from the fundus of the eye to be examined is substantially transferred to the perforated mirror. It is reflected by the beam and taken out coaxially with the optical axis of the light source beam for observation and photography.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A dilated fundus camera, which is an embodiment of the present invention, will be described below with reference to the drawings.

As shown in FIG. 1, the mydriatic fundus camera of the embodiment includes an illumination system A, an observation and photographing system B, a focus detection system C, and a display system.

The illumination system A is for illuminating the fundus Eb of the eye E to be examined. The illumination system A includes a reflecting mirror 1, an observation light source 2 such as a halogen lamp, a condenser lens 3, a photographing light source 4 such as a xenon lamp, a condenser lens 5, and a ring-shaped aperture diaphragm 6 arranged in order on the optical axis O2. , a long-pass filter 7, a relay lens 8 and a relay lens 9 arranged in order on an optical axis 02 obliquely intersecting the optical axis O1, a perforated mirror 10 having a hole, and an optical axis o3 obliquely intersecting the optical axis 0□. It consists of an objective lens 11 disposed above and facing the eye E to be examined.

As shown in FIG.
It has the characteristics of reflection and λ2 (infrared light) transmission. Further, the hole portion of the perforated mirror 10 has a reflective surface.
A guichroic mirror 108 is disposed, which has the same reflective surface as the peripheral area excluding the hole of 0, and has the characteristics of transmitting λ1 (visible light) and reflecting λ2 (infrared light), as shown in FIG. .

The ring-shaped aperture diaphragm 6, which is uniformly illuminated by the viewing light source 2 and the photographing light source 4, is connected to the perforated mirror 10 with respect to the optical system consisting of the reflecting mirror 7 and the relay lens 8.9.
There is a conjugate relationship with Further, the perforated mirror 10 is in a conjugate relationship with the anterior segment Ep of the eye E to be examined with respect to the objective lens 11. Therefore, the ring-shaped aperture diaphragm 6 and the anterior eye segment El) of the eye E to be examined are in an optically conjugate relationship.

The observation and photographing system B for observing and photographing the fundus Eb has the optical axis 0. It includes an objective lens 11, a focusing lens 13, an imaging lens 12, and a flip-up mirror 14 arranged in this order at the top. In addition to the flip-up mirror 14 that is not flipped up, the observation unit also has a reflection optical axis 0.0 of the flip-up mirror 14. A field lens 15, a reflective prism 16, and an eyepiece 17 facing the examiner P are arranged in this order at the top.
has. The photographing section includes an objective lens 11, a focusing lens 13, an imaging lens 12, the flip-up mirror 14, and a film 18, which are arranged in this order on the optical axis O5.

The focus detection system C includes a focusing infrared light source 50. on the optical axis O1.
An index mask 5 with a condenser lens 52 and a deflection prism 54 arranged so that the infrared light source 50 is at the front focal point.
6. Lens 58, mirror 60, reflection optical axis 0 of mirror 60
7, a two-hole aperture 62, and an infrared half mirror 64. The index mask 56 includes a lens 58 and a relay lens 8.
．． 9. Regarding the objective lens 11, it is conjugate with the fundus of the eye to be examined.

The two-hole aperture 62 includes a relay lens 8.9 and an objective lens 11.
It is conjugate with the anterior segment Ep of the subject's eye.

The optical axis O9 coincides with the optical axis 02 after passing through the long pass filter 7.

The deflection prism 54 is formed by pasting a pair of wedge-shaped prisms 68 and 69 on an index mask 56 with the optical axis 06 as a point of symmetry, as shown in FIG. As shown in FIG. 4, the index mask 56 is provided with a vertically long slit 70 centered on the optical axis 06. As shown in FIG. 5, the two-hole diaphragm 62 has an optical axis of 0. A pair of circular hole apertures 74 and 76 are provided symmetrically and separated from each other in the horizontal direction with the center at the center.

The focus detection system C further includes a lens 80 and a detector 82 arranged on the reflection optical axis 08 of the infrared half mirror 64. The detector 82 includes a lens 80 and a relay lens 8.9.
, the objective lens 11 is conjugate with the fundus Eb of the eye to be examined.

The display system is for presenting the focusing state, photographing conditions, etc. to the examiner and displaying them on the film 18.
8, a display half mirror 31 disposed between the focusing lens 13 and the imaging lens 12, a mirror 32 disposed on the reflection optical axis 05 of the display half mirror 31, a relay lens 33, and a display 34. Consists of.

The display surface i of the display 34 is in a conjugate relationship with the film 18 with respect to the imaging lens 12. The display half mirror 31 is a half mirror for visible light, and for example, reflects 50% of the incident light beam and transmits 50% of it.

Next, the operation of the fundus camera having the above configuration will be explained.

An infrared light source 50 and a condenser lens 52 illuminate an index mask 56 with a substantially parallel light beam. The infrared focused beam exiting the index mask 56 passes through the lens 58.2.
The light reaches the fundus Eb of the subject's eye via the aperture diaphragm 62, the infrared half mirror 64, the long pass filter 64, the relay lens 8.9, the periphery of the perforated mirror 10, and the objective lens 11.

At the time of focusing, the infrared focused light beam exiting the index mask 56 enters from an off-axis symmetrical position centered on the optical axis 03 of the anterior segment Ep of the subject's eye due to the action of the deflection prism 54 and the two-hole diaphragm. The focused infrared light beam forms two point images that match on the fundus Eb of the eye to be examined, and when out of focus, the infrared focused light beam forms two separate point images on the fundus Eb of the eye to be examined.

The reflected infrared focused light flux on the fundus Eb of the subject's eye passes through the objective lens 11, the guichroic mirror 10a, the relay lens 9.8, the long pass filter 64, the infrared half mirror 64, and the lens 80 to the detector. 82, and the focused infrared beam in the fundus Eb of the eye to be examined is imaged again on the detector 82. The detector 82 detects the image formation state in the fundus Eb of the eye to be examined, that is, the state of coincidence or separation of the two focused infrared light beams. The output of the detector 82 is input to the display 34.

During observation, the fundus Eb of the eye to be examined is illuminated by turning on the observation light source 2 and placing the flip-up mirror I4 at the solid line position in FIG. The observation visible light flux emitted from the observation light source 2 is
The fundus Eb of the subject's eye is illuminated through the condenser lens 3, the condenser lens 5, the ring-shaped aperture diaphragm 6, the long-pass filter 7, the relay lens 8.9, the periphery of the perforated mirror 10, and the objective lens 11. Due to the action of the ring-shaped aperture diaphragm 6, the visible light beam for observation passes through the periphery of the anterior segment Ep of the eye to be examined and reaches the fundus Eb of the eye to be examined.

During photography, the photography light source 4 is turned on to illuminate the fundus Eb of the subject's eye in the same manner as during observation.

Observation of the fundus Eb of the subject's eye is such that the light flux reflected on the fundus Eb of the subject's eye is directed to the center of the anterior segment Ep of the subject's eye, the objective lens 11,
Dichroic mirror 10a (passing), focusing lens 1
3. It is performed by the examiner P via the half mirror 31 and the imaging lens 12, and further via the flip-up mirror 14 on the optical axis 01, the field lens 15, the reflection prism 16, and the eyepiece lens F.

When photographing the fundus Eb of the eye to be examined, the flip-up mirror 14 is set to the optical axis 0.
It is done by jumping up from 3.

Note that during the above-mentioned observation and photographing, the display indicating the in-focus state, photographing conditions, and subject information displayed on the display 34 are displayed superimposed on the fundus image of the subject's eye.

(Effects of the Invention) According to the present invention, the focusing light beam enters the observation and photographing system along the same optical axis as the illumination light beam, and the focusing light beam is reflected by the fundus Eb of the subject vi. Since the light is extracted from the observation and photography system along the same optical axis as the illumination light beam, the observation and photography system does not require a special space for focusing, and the fundus camera as a whole can be made compact. has advantages.

[Brief explanation of the drawing]

Fig. 1 is an optical diagram of a fundus camera according to an embodiment of the present invention, Fig. 2 is a spectral characteristic graph of a long-pass filter, Fig. 3 is a spectral characteristic graph of a dichroic mirror, and Fig. 4 is a plan view of an index mask. FIG. 5 is a plan view of the two-hole aperture. A-m-Illumination system B--Observation and photographing system C--Focus detection system D--Display system E--Eye to be examined 2--Observation light source 4--Photographing light source 6--Ring Aperture diaphragm 7 - Long pass filter - Perforated mirror Oa - Dichroic mirror - Objective lens 0 - Infrared light source 4 - Deflection prism 6 - Index mask 2 - 2 Hole diaphragm 4 - -Infrared light half mirror- 0-・Slit

Claims (2)

[Claims] (1) An illumination system for illuminating the fundus of the examinee's eye with light in a first wavelength range via a perforated mirror, and a fundus image formed by the reflected light from the fundus of the examinee's eye illuminated by the illumination system. An observation and photographing system for observing and photographing through the hole of the perforated mirror, and an index light beam for focusing on the fundus of the eye to be examined using light in a second wavelength range different from the first wavelength range; In a fundus camera having a focus detection system for detecting a focus state by receiving the reflected light of the projected index light beam, the light in the first wavelength range is transmitted through the hole of the perforated mirror. An optical member that reflects light in the wavelength range of 2 is provided, and the focus detection system projects the index light beam onto the fundus via the wavelength division reflector, and projects the reflected light from the fundus via the wavelength division reflector. A fundus camera configured to receive light. (2) The fundus camera according to claim 1, wherein the light in the first wavelength range is visible light, and the light in the second wavelength range is infrared light.