JP4659173B2 - Fundus camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fundus camera used in an ophthalmic hospital or the like.
[0002]
[Prior art]
A conventional fundus camera of this type includes an optical unit that projects a light beam onto an eye to be examined and guides the reflected light beam to an image receiving unit, an alignment unit that manually or automatically aligns the optical unit with the eye to be examined, and an image received by the image receiving unit. And a monitor for displaying the anterior ocular segment image or fundus image.
[0003]
The optical unit is an anterior ocular segment illumination light source that illuminates the anterior ocular segment, an anterior ocular segment observation optical path that guides reflected light flux from the anterior ocular segment to the imaging means, a fundus illumination light source that illuminates the fundus, and a luminous flux from the fundus illumination light source A fundus illuminating optical path leading to the eye, a fundus observing optical path for guiding the reflected light beam from the fundus to the imaging element means, a display means for displaying the anterior segment image and the fundus image captured by the imaging means, and a fixation target for stabilizing the line of sight of the subject's eye Etc.
[0004]
When observing or photographing the eye, the optical unit is aligned and focused on the eye while observing the anterior segment image displayed on the display means, and then the photographing switch is operated. Take a picture of the fundus.
[0005]
On the other hand, the optical unit includes an objective lens for the eye to be inspected, and a fundus illumination optical path and a fundus observation imaging optical path are divided by a perforated mirror arranged substantially conjugate with respect to the objective lens, and the lens is inserted into the fundus observation imaging optical path to insert the anterior eye The partial image may be observed from an oblique direction. In addition, when the light flux from the fundus illumination light source is projected as visible light on the fundus, the fundus is observed with an optical system finder, and when projected onto the fundus as infrared light, the fundus is imaged by an imaging unit and displayed by a display unit. Sometimes observed.
[0006]
Furthermore, the fundus camera disclosed in Japanese Patent Laid-Open No. 53-129059 has mirrors arranged on both sides of the fundus observation photographing optical path in the vicinity of the perforated mirror, and a focus lens is arranged on the fundus observation photographing optical path. is doing. Then, the focus light from the focus light projection system is projected onto the fundus through a mirror, and the focus light projection system and the focus lens are integrally driven to perform focusing.
[0007]
[Problems to be solved by the invention]
However, it is difficult for the conventional fundus camera to accurately position and focus the anterior segment image on the screen. In addition, since it is not easy to switch between the anterior ocular segment image and the fundus oculi image, it is impossible to capture the ocular fundus image while observing the anterior ocular segment image. When alignment is performed using infrared light, it is not easy to photograph the vicinity of the fundus. Furthermore, when observing the anterior segment, the fixation target cannot be projected, and the fundus cannot be observed with infrared light and visible light. In a fundus camera that performs focusing by driving the focus light projection system and the focus lens integrally, the amount of focus adjustment is small compared to the amount of movement of the focus lens. There is a problem.
[0008]
An object of the present invention is to provide a fundus camera capable of solving the above-described problems, performing accurate positioning, and improving operability.
[0009]
[Means for Solving the Problems]
A fundus camera for achieving the above object has a focus light projection system for projecting focus light onto the fundus through a mirror disposed in the vicinity of a perforated mirror, and a focus lens disposed in an optical path for photographing a fundus image In the fundus camera that drives the focus light projection system and performs focusing, two concave lenses having the same focal length are arranged symmetrically with respect to the mirror in the optical path for photographing the fundus image and the optical path of the focus light projection system It is characterized by that.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail based on the illustrated embodiment.
FIG. 1 is an optical configuration diagram of a first embodiment of a fundus camera. The fundus camera projects a light beam from an anterior segment illumination light source 1 or a fundus illumination light source 2 that is selectively lit onto an eye E to be examined. An optical unit (not shown) for guiding the reflected light beam to the color digital camera 3 or the monochrome video camera 4 having sensitivity to visible light and infrared light, and an alignment unit (not shown) for manually or automatically aligning the optical unit with the eye E to be examined. A monitor 5 for displaying an anterior ocular segment image and a fundus image captured by the monochrome video camera 4 is provided.
[0016]
The anterior segment illumination light source 1 is a light emitting diode that emits infrared light having a dominant wavelength of 780 nm as indicated by a characteristic curve a in FIG. Then, the examiner performs the alignment and focusing of the optical unit with respect to the eye E while observing the anterior segment image reflected on the monitor 5, and operates the photographing switch (not shown) to photograph the fundus image with the color digital camera 3. It is supposed to be.
[0017]
In the fundus illumination optical path O1 through which the light beam from the fundus illumination light source 2 travels, a filter 6a that transmits infrared light having a wavelength of 800 nm or more shown by the characteristic curve b in FIG. 2 or a filter 6b that transmits visible light shown by the characteristic curve c. Are selectively inserted into the optical path O1, a filter unit 6, a lens 7, a fundus photographing strobe light source 8, a ring slit 9, a lens 10, visible light indicated by a characteristic curve d in FIG. 3, and infrared light having a wavelength of 800 nm or more. A dichroic mirror 11, a lens 12, and a perforated mirror 13 that sequentially transmit infrared light having a wavelength of 700 to 800 nm are sequentially arranged. An objective lens 14 that forms an image of the pupil of the eye E in the vicinity of the perforated mirror 13 is disposed in the fundus observation photographing optical path O2 in front of the eye E. The anterior ocular segment illumination light source 1 is disposed around the objective lens 14, and the lens 7 images the fundus illumination light source 2 on the ring slit 9.
[0018]
In the transmission direction of the perforated mirror 13, the focus light reflection mirror 15, the concave lens 16, the focus lens 17 that moves on the optical path O2, the imaging lens 18, the optical path switching mirror 19, the relay lens 20, The aforementioned color digital cameras 3 are sequentially arranged. The anterior segment imaging optical path O3 divided by the dichroic mirror 11 reflects most of infrared light and visible light having a wavelength of 800 nm or more indicated by the characteristic curve e in FIG. A dichroic mirror 22, a lens 23, and the monochrome video camera 4 described above are sequentially disposed.
[0019]
A lens 24, a dichroic mirror 22, a lens 25, and a fixation target 26 are sequentially arranged in the fundus observation fixation target optical path O4 in the incident direction of the optical path switching mirror 19. A concave lens 27, a mirror 28, and a split light projection system 29 are arranged on the focus light projection optical path O5 incident on the focus light reflection mirror 15. The concave lens 27 has the same focal length as the concave lens 16 and is disposed symmetrically with the concave lens 16 with respect to the focus light reflecting mirror 15. The split light projection system 29 emits infrared light and is driven in the optical axis direction in conjunction with the focus lens 17.
[0020]
When the anterior segment illumination light source 1 illuminates the anterior segment of the eye E, the reflected light beam from the anterior segment is transmitted through the objective lens 14 and reflected by the perforated mirror 13, and transmitted through the lens 12 and dichroic mirror 11. , And reaches the monochrome video camera 4 through the lens 21, dichroic mirror 22, and lens 23, and an anterior segment image is captured. At this time, if the eye E is in the correct position, the pupil is conjugate with the imaging surface of the monochrome video camera 4.
[0021]
The light beam from the fundus illumination light source 2 passes through the filter 6 a of the filter unit 6 to become infrared light, and is projected onto the fundus of the eye E through the dichroic mirror 11, the perforated mirror 13, and the objective lens 14. The reflected light from the fundus passes through the hole of the perforated mirror 13, is reflected by the optical path switching mirror 19, is reflected by the dichroic mirror 22, and is captured by the monochrome video camera 4.
[0022]
When split light based on infrared light is projected onto the fundus from the split light projection system 29, the reflected light beam of the split light on the fundus is a monochrome video camera via the hole in the perforated mirror 13, the optical path switching mirror 19, and the dichroic mirror 22. 4 and the split image S is displayed on the monitor 5. The light beam from the fixation target 26 passes through the dichroic mirror 22, is reflected by the optical path switching mirror 19, passes through the hole of the perforated mirror 13, and is projected onto the eye E to be examined.
[0023]
When aligning the optical unit with respect to the eye E, the anterior segment illumination light source 1 is turned on and the anterior segment image F is displayed on the monitor 5. At this time, since the alignment mark M is also displayed on the monitor 5, the optical unit is driven so that the pupil image is aligned with the alignment mark M, and the alignment of the optical unit and the focusing of the pupil image are performed. Then, after completing the positioning and focusing, a shooting switch (not shown) is pressed. As a result, the optical path switching mirror 19 is retracted to the outside of the optical path, the photographing strobe light source 8 emits light, and a fundus image that is reflected light from the illumination light is photographed by the color digital camera 3 with visible light.
[0024]
In the first embodiment, by switching between the anterior ocular segment illumination light source 1 and the fundus illumination light source 2, the anterior segment image F and the fundus image can be selectively displayed on the monitor 5, and the anterior segment image F is observed. If the shutter is pressed, the fundus image can be taken. Even if either the anterior ocular segment illumination light source 1 or the fundus illumination light source 2 is selected, the split image S is displayed on the monitor 5 at a position corresponding to the center of the fundus, so that the fundus is focused while observing the anterior segment. it can. Further, while the anterior eye portion is displayed on the monitor 5, the fixation target 26 is presented to the eye E in the same manner as when observing the fundus, so that the eye E is stabilized and easily aligned. be able to.
[0025]
When the fundus is observed with infrared light, the lesion may not be clearly determined. In this case, the filter 6b is inserted into the fundus illumination optical path O1 instead of the filter 6a of the filter unit 6, and the fixation target 26 cannot be used and is turned off. As a result, the luminous flux from the fundus illumination light source 2 is projected as visible light onto the fundus, and the reflected luminous flux from the fundus is photographed by the monochrome video camera 4 via the optical path switching mirror 19 and the dichroic mirror 22, and a fundus image of visible light is obtained. It is displayed on the monitor 5. At this time, the reflected light beam from the fundus becomes a parallel light beam between the focus lens 17 and the imaging lens 18 when the subject is in focus. Since the concave lenses 16 and 27 act to reduce the amount of movement of the focus lens 17 and the split light projection system 29, the diopter of the eye E can be adjusted in a wide range by their small movement.
[0026]
FIG. 4 is an optical configuration diagram of the second embodiment, and members having functions similar to those of the first embodiment are denoted by the same reference numerals. The dichroic mirror 11 in the fundus illumination optical path O <b> 1 is moved between the ring slit 9 and the lens 10. Further, the focus light reflecting mirror 15, the concave lens 16, the focus lens 17, the imaging lens 18, the concave lens 27, the mirror 28, and the split light projection system 29 of the first embodiment are removed, and instead of the split light projection system for focus. 31 is disposed between the lens 10 and the lens 12 in the fundus illumination optical path O1, and the focus lens 32 and the imaging lens 33 are disposed between the apertured mirror 13 and the optical path switching mirror 19 in the optical path O2.
[0027]
In the split light projection system 31, a bar mirror 31a is arranged in a conjugate manner with the fundus oculi, so that the light beam from the light source 31b is reflected by the perforated mirror 13, and the split light projection system 31 and the focus lens 32 are interlocked. . When the fundus is observed and photographed with visible light, the rod mirror 31a of the split light projection system 31 is driven out of the optical path O1.
[0028]
Reflected light from the anterior eye part is reflected by the perforated mirror 13 and the dichroic mirror 11, passes through the dichroic mirror 22, is photographed by the monochrome video camera 4, and the anterior eye part image F is displayed on the monitor 5. In addition, the split light obtained by reflecting the light from the light source 31b by the rod mirror 31a in the split light projection system 31 is reflected by the perforated mirror 13 and projected onto the fundus. When the fundus is observed and photographed with visible light, the rod mirror 31a of the split light projection system 31 is retracted out of the optical path O1, and the light flux from the fundus illumination light source 2 is projected onto the fundus as visible light. The reflected light beam at the fundus is reflected by the optical path switching mirror 19 and the dichroic mirror 22 through the hole of the perforated mirror 13, the focus lens 32, and the imaging lens 33, and is captured by the monochrome video camera 4.
[0029]
In this second embodiment, the rod mirror 31a of the split light projection system 31 is conjugate with the fundus and the light flux of the split light projection system 31 is thick, so that the shadow of the split image S appears on the anterior eye image F. There is no reflection. Then, by selectively turning on the anterior ocular segment illumination light source 1 or the fundus illumination light source 2, the anterior segment image F and the fundus image can be displayed on the monitor 5. In any case, the focus split image S is displayed. Needless to say, the fixation target 26 can be presented to the subject.
[0030]
【The invention's effect】
As described above, since the anterior segment is observed through the light splitting member provided in the fundus illumination optical path, the anterior segment image and the fundus can be switched by switching between the anterior segment illumination light source and the fundus illumination light source. Images can be switched easily, the fundus can be photographed while observing the anterior segment image, and operability can be improved.
Further, since the two concave lenses having the same focal length are arranged symmetrically with respect to the mirror in the fundus photographing optical path and the optical path of the focus light projection system, the diopter adjustment range can be expanded.
[Brief description of the drawings]
FIG. 1 is an optical configuration diagram of a first embodiment.
FIG. 2 is a graph showing the transmittance of a filter and the intensity of an anterior ocular segment illumination light source.
FIG. 3 is a graph showing the transmittance of a dichroic mirror.
FIG. 4 is an optical configuration diagram of the second embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Anterior eye part illumination light source 2 Fundus illumination light source 3 Color digital camera 4 Monochrome video camera 5 Monitor 6 Filter unit 11, 22 Dichroic mirror 13 Perforated mirror 14 Objective lens 15 Focus light reflection mirror 16, 27 Concave lens 17, 32 Focus lens 19 Optical path switching mirror 26 Fixation target 29, 31 Split light projection system

Claims (3)

  A focus light projection system that projects focus light onto the fundus through a mirror disposed in the vicinity of the perforated mirror, and driving the focus lens and the focus light projection system disposed in the optical path for photographing the fundus image A fundus camera for focusing, wherein two concave lenses having the same focal length are arranged symmetrically with respect to the mirror in an optical path for photographing the fundus image and an optical path of the focus light projection system. A second imaging unit that images the anterior segment to the imaging unit via a member that divides light provided in an optical path for capturing the fundus image, and a display that displays the captured fundus image and anterior segment image And a projection means for projecting the fixation target onto the eye to be examined via the focus lens and a member that divides the light, and the fixation target is displayed when the anterior eye part is displayed on the display means. The fundus camera according to claim 1, wherein the fundus camera is projected onto an optometry. First illumination means for selectively illuminating the fundus with either one of infrared light or visible light, and illuminating the anterior eye portion with infrared light having a wavelength different from that of the infrared light of the first illumination means Second illuminating means, a first optical path for guiding illumination light of the first illuminating means to the imaging means, and a second optical path for guiding illumination light of the second illuminating means to the imaging means. The fundus camera according to claim 1, further comprising:

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