JP2013176699A - Ophthalmologic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a correct alignment operation by correcting a deviation of an optical path length of an alignment index, that is caused by a wavelength difference when the wavelength of an observation light source is changed.SOLUTION: An ophthalmologic apparatus includes: a photographing optical system for allowing a photographing means to form an image of return light from an eye to be examined that is illuminated via an illumination optical system; a selection means for selecting the wavelength of alignment index light indicating position relation between the photographing optical system and the eye to be examined in the optical axial direction of the photographing optical system; and an index projection means for projecting the alignment index light with the selected wavelength onto the eye to be examined. The photographing optical system is configured to adjust an optical path length difference corresponding to the wavelength difference of the alignment index light to be projected onto the eye to be examined by the index projection means.

Description

  The present invention relates to an ophthalmic apparatus.

  In recent years, particularly in the fundus camera of the fundus oculi observation device, in order to suppress the burden on the subject as much as possible, mydriatic imaging and non-mydriatic imaging can be performed with a single fundus camera according to the examination contents / A non-mydriatic fundus camera is used.

  In general, infrared light is used for observation before non-mydriatic imaging, and visible light is used for observation before mydriatic imaging. In Patent Document 1, visible light and infrared light are selectively used as a light source for eye observation, and the alignment index projection light source is changed in accordance with the observation light source, thereby improving the alignment index visibility. ing.

  Patent Document 2 discloses a fundus camera that selectively uses visible light and infrared light as a light source for eye observation and uses near infrared light as an alignment light source. In this fundus camera, the visibility of the alignment index is improved by increasing the light amount of the alignment light source in the case of visible light observation than in the case of infrared light observation.

  Also, in Patent Document 3, flare is suppressed by moving the projection position of the alignment index in the optical axis direction when photographing the fundus central part of the eye to be examined and when photographing the peripheral part. Yes.

Japanese Patent Laid-Open No. 7-100112 JP 2003-305209 A JP 2000-287934 A

  However, as shown in Patent Document 1, when the wavelength of the alignment index projection light source is changed, the focal point changes due to the wavelength difference, the alignment index is shifted, and accurate focusing becomes difficult.

  In addition, the method of changing the luminance according to the observation wavelength using the alignment index shown in Patent Document 2 as near-infrared light needs to improve the intensity of light with a wavelength that is difficult to see during visible light observation. Even if this method can be recognized by the examiner, it cannot be said that the visibility is good for the subject.

  The technique for suppressing flare by moving the projection position of the alignment index shown in Patent Document 3 does not devise a technique for improving the visibility when the characteristics of the observation light source are changed.

  One of the objects of the present invention is to solve the above-mentioned problems, and when switching the observation light source, select a color of an alignment index that has good visibility with respect to the light source, and for the selected color An object of the present invention is to provide an ophthalmologic apparatus capable of obtaining an optimum focus state.

The ophthalmic apparatus according to the present invention is
An imaging optical system that forms an image on the imaging means of the return light from the eye to be illuminated illuminated through the illumination optical system;
Selecting means for selecting a wavelength of alignment index light indicating a positional relationship between the photographing optical system and the eye to be examined in an optical axis direction of the photographing optical system;
Index projection means for projecting the alignment index light of the selected wavelength onto the eye to be examined,
The imaging optical system is configured such that an optical path length difference corresponding to a wavelength difference of alignment index light projected onto the eye to be examined by the index projection unit is adjusted.

  According to the ophthalmologic apparatus of the present invention, when an alignment index having a different wavelength is projected according to switching of the observation light source, an optical path length deviation caused by a difference in the wavelength of the alignment index is corrected, thereby realizing an accurate alignment operation. To do.

1 is a configuration diagram of a fundus camera of Example 1. FIG. It is an expanded view of a split optical system. It is an optical path figure in the state which projected the alignment parameter | index with visible light. It is an optical path diagram in a state where the light source is changed from visible light to infrared light without adjusting the position of the alignment index. It is an optical path diagram in a state where the position of the alignment index is adjusted and the light source is changed from visible light to infrared light. It is a block circuit block diagram. It is an operation | movement flowchart for switching the color and position of an alignment parameter | index. FIG. 6 is a configuration diagram of Example 2.

  The present invention will be described in detail based on the embodiments shown in the drawings.

Example 1
FIG. 1 is a configuration diagram of a fundus camera that is an example of an ophthalmologic apparatus according to the first embodiment. The illumination optical system from the halogen lamp 1 to the objective lens 2 disposed in front of the eye E includes a halogen lamp 1 as an observation light source, a xenon lamp 3 as a photographing light source, a visible light ring slit 4, and a dichroic on the optical path L1. The mirrors 5 are arranged. A relay lens 6, a prism unit 7, a relay lens 8, and a perforated mirror 9 are arranged on the light path L 2 on the reflection side of the dichroic mirror 5. Further, an infrared LED 10 and an infrared ring slit 11 which are observation light sources are provided in the same direction as the optical path L2 behind the dichroic mirror 5.

  The halogen lamp 1 is a first observation light source of visible light used when observing the fundus Er of the eye E to be examined. The xenon lamp 3 is an imaging light source used when photographing the fundus Er of visible light. This is a second observation light source used when observing the fundus Er with infrared light. The visible light ring slit 4 is a mask for making illumination light from the xenon lamp 3 and the halogen lamp 1 into ring illumination, and the infrared ring slit 11 is a mask for making illumination light from the infrared LED 10 into ring illumination. is there. Further, the dichroic mirror 5 has a characteristic of reflecting visible light and transmitting infrared light.

  The prism unit 7 is provided with a split mask 7a on the optical path L2, and a split prism 7b is attached behind the split mask 7a. A dichroic mirror 7c is arranged in the reflection direction of the split prism 7b, a visible LED 7d is arranged in the transmission direction of the dichroic mirror 7c, and a near-infrared LED 7e is arranged in the reflection direction of the dichroic mirror 7c. Further, the prism unit 7 is provided with a split drive motor 12 and a split position detecting means 13 so that the prism unit 7 can be driven to move the split image on the fundus Er and to detect the position thereof. Yes.

  On the optical path L3 in front of the eye E, the objective lens 2, the perforated mirror 9, the aperture 14, the focus lens 15, the movable mirror 16, and the image sensor 17 are sequentially arranged to constitute an observation and photographing optical system. . The focus lens 15 is provided with a focus lens drive motor 18 and a focus lens position detection means 19 so that the focus lens 15 is driven to focus, and its position is detected.

  Further, a fixed mirror 20 and a viewfinder eyepiece lens 21 are disposed on the optical path L4 in the reflection direction of the movable mirror 16, and a visible light observation optical system is configured.

  A light guide 22 a of an alignment index unit 22 for adjusting the positional relationship between the observation photographing optical system and the eye E is disposed in the hole portion of the perforated mirror 9. The alignment index unit 22 includes a light guide 22a directed to the eye E, a visible LED 22b provided near the incident portion of the light guide 22a (visible band alignment index light), and infrared light (red). And an infrared LED 22c that generates alignment index light in the outer band. The visible LED 22b and the infrared LED 22c are juxtaposed in the optical axis direction, and the incident portion of the light guide 22a faces in the direction orthogonal to the optical axis. The alignment index unit 22 is additionally provided with an alignment index drive motor 23 that serves both as a movement control unit for the alignment index unit 22 and an index light source switching unit, and an alignment index position detection unit 24.

  The fundus camera is provided with a focus adjustment knob 25, focus adjustment detection means 26, and an observation light source selection switch 27. The observation light source selection switch 27 can alternatively select visible / infrared light from the halogen lamp 1 and the infrared LED by the operation of the examiner.

  When observing the fundus of the eye E, the visible light emitted from the halogen lamp 1 is reflected by the dichroic mirror 5 through the xenon lamp 3 and the visible light ring slit 4. The visible light reflected by the dichroic mirror 5 passes through the relay lens 6, the prism unit 7, and the relay lens 8, is reflected by the perforated mirror 9, and enters the eye E through the objective lens 2.

  Further, at the time of fundus observation, the infrared light emitted from the infrared LED 10 passes through the infrared ring slit 11 and the dichroic mirror 5 and then enters the eye E through the same optical path as the illumination light from the halogen lamp 1. . At this time, the optical paths of the visible ring illumination light and the infrared ring illumination light are combined by the dichroic mirror 5, and the ring illumination is imaged on the fundus Er of the eye E by the relay lenses 6 and 8.

  The fundus image obtained by the illumination is imaged by the objective lens 2 at the position of the stop 14 near the perforated mirror 9 and further advances through the observation and photographing optical system. The focus lens 15 adjusts the focus of the photographic light that has passed through the perforated mirror 9 by moving in the direction of the arrow by operating the focus adjustment knob 25. The focus adjustment knob 25 can be adjusted to a desired focus state by an operator's operation, and the position is detected by the focus adjustment detection means 26.

  The movable mirror 16 is lowered as shown in the figure when observing the visible light, and the fundus image is guided to the finder eyepiece 21 via the fixed mirror 20 of the visible light observation optical system, and the examiner can observe it via the finder eyepiece 21. Become. The movable mirror 16 rises at the time of infrared observation and photographing, and guides photographing light to the image pickup device 17 of the observation photographing optical system. The imaging element 17 photoelectrically converts the photographic light, and the obtained electrical signal is A / D converted by a processing circuit, and the photographic image is displayed on a display means (not shown) during infrared observation, and recorded on a recording medium during photographing.

  FIG. 2 is a development view of the split optical system according to the first embodiment. The reflecting surface of the split prism 7b and the reflecting surface of the perforated mirror 9 are omitted, and the optical system is shown expanded. As shown to (a), the light beam at the time of lighting of visible LED 7d permeate | transmits the dichroic mirror 7c, and is divided | segmented by the split prism 7b. The split image becomes a linear image by the split mask 7a disposed at a position close to the split prism 7b. As a result, the two split images formed on the perforated mirror 9 by the relay lens 8 and further divided on the fundus Er by the objective lens 2 are projected in a straight line as in the case of split visible LED emission.

  When the visible LED 7d that is lit in this state is switched to the near-infrared LED 7e as shown in (b), the optical path length changes due to chromatic aberration caused by the LED color difference (wavelength difference of the alignment index light). That is, an optical path length difference corresponding to the wavelength difference of the alignment index light occurs due to the difference in color of the LEDs. When the near-infrared LED 7e is turned on, the light beam is reflected by the dichroic mirror 7c, and thereafter travels in the same optical path as the visible LED 7d. However, as a result of the extension of the optical path length due to chromatic aberration, an image is formed farther than the fundus Er, and the two split images are shifted from each other as shown in FIG.

  Therefore, a table is provided in which the stop position of the prism unit 7 in the optical axis direction is shifted in accordance with the observation light set by the observation light source selection switch 27 with respect to the stop position of the focus adjustment knob 25.

  In the alignment index unit 22, the visible LED 22b, which is a visible index light source, emits green light of 530 to 580 nm (an example of alignment index light in the visible band), and has good visibility during visible light observation. The infrared LED 22c, which is an infrared index light source, emits near-infrared light of about 700 nm (an example of alignment index light in the infrared band) and is dazzling even in the eye E that is not dilated while maintaining visibility. Miosis can be prevented without feeling.

  FIG. 3 shows an optical path diagram in a state in which an alignment index is projected with visible light by the visible LED 22b. Visible light incident from the incident portion of the light guide 22a serving as the index projection means travels straight inside, and the light beam reflected by the reflecting surface travels straight at a different angle to form a bright spot at the exit portion. The bright spots formed here are imaged slightly inside the anterior segment Ep of the eye E by the objective lens 2. The alignment index image composed of the bright spots is synthesized with the fundus image, and is observed through the finder eyepiece 21 in the case of mydriatics, that is, in the case of visible light observation. At this time, if a bright spot of the alignment index exists on the left and right of the fundus image by observation, it indicates that the optical axis of the fundus camera and the eye E is aligned, and if the bright spot is clear and displayed clearly This shows that the working distance between the fundus camera and the eye E to be examined is the same.

  FIG. 4 shows an optical path diagram in a state where the observation light source is changed from the visible light of the halogen lamp 1 to the infrared light of the infrared LED 10 without adjusting the bright spot position of the alignment index. In the infrared light observation state, the movable mirror 16 is flipped upward, and the optical path is switched to the image sensor 17 side. Here, when the visible LED 22b having a long wavelength is used, the optical path length becomes long, and the index position where the image is finally formed is shifted backward from the image sensor 17. Therefore, if the bright spot position of the alignment index is not adjusted, the operation is performed. The distance cannot be adjusted correctly.

  FIG. 5 shows an optical path diagram in a state in which the position of the alignment index is adjusted in this case and the visible LED 22b is changed to the infrared LED 22c. Here, the index projection means is moved to a position on the optical axis of the photographing optical system corresponding to the wavelength of the alignment index light. The light guide 22a is moved by the alignment index drive motor 23 so that the incident part faces the infrared LED 22c. At this time, the emission part of the light guide 22a is set at a position where an image is formed on the image sensor 17 when the working distance is appropriate at the wavelength of the infrared LED 22c. That is, the visible LED 22b and the infrared LED 22c are aligned in the optical axis direction, and the distance between the visible LED 22b and the infrared LED 22c is aligned with a distance for forming an image on the image sensor 17 when the working distance is appropriate. By adopting such a configuration, if the light guide 22a is moved, the facing LED changes, so that the emission point, that is, the bright spot position of the alignment index can be changed while changing the emission color.

  FIG. 6 is a block circuit configuration diagram. All operations of the fundus camera are controlled by the CPU 31, and the observation light source selection switch 27 selects infrared light observation / visible light observation according to the observation mode desired by the subject. In this embodiment, the observation light source is directly selected by the observation light source selection switch 27. However, a non-mydriatic mode for observing the eye to be examined with infrared light and a mydriatic mode for observing the eye to be examined with visible light are used. A switch that selects any one of a plurality of modes may be used. At this time, even if the selected photographing mode is selected from non-mydriatic / mydriatic photographing, the infrared light / visible light from the observation light source is selected in conjunction with each other. That is, when the non-mydriatic mode is selected, infrared alignment index light is projected onto the eye to be examined, and when the mydriatic mode is selected, visible alignment index light is projected onto the eye to be examined.

  Further, the alignment index drive motor 23 and the alignment index position detection means 24 are connected to the CPU 31 so that the alignment index can be moved to a desired position and its position can be detected. Switching between the visible LED 22b and the visible LED 22c is also controlled by the CPU 31, and can be turned on and off when desired.

  FIG. 7 is an operation flowchart of the CPU 31 for switching the color and position of the alignment index. The operation is started in step S1, the state of the observation light source selection switch 27 is confirmed in step S2, and if visible light is selected, the process proceeds to step S3, and if infrared light is selected, the process proceeds to step S4. In step S3, the state of the alignment index is confirmed by the alignment index position detection means 24. If it is in the infrared light state, the process proceeds to step S5, and if it is in the visible light state, the process proceeds to step S6. In step S5, the alignment index drive motor 23 moves the light guide 22a, thereby moving the position of the alignment index to the visible LED 22b.

  In step S6, the visible LED 22b is turned on to project the alignment index, and the process proceeds to step S7 to end a series of sequences.

  In step S4, the state of the alignment index is confirmed by the alignment index position detection means 24. If it is in the visible light state, the process proceeds to step S8, and if it is in the infrared light state, the process proceeds to step S9.

  In step S8, the position of the alignment index is moved to the infrared LED 22c by moving the light guide 22a by the alignment index drive motor 23. In step S9, the infrared LED 22c is turned on to project the alignment index, and the process proceeds to step S7 to end a series of sequences.

  In the present embodiment, the alignment index is generated using the light guide 22a, but the same effect can be obtained even if this is an optical fiber or other light guide member.

(Example 2)
FIG. 8 is a configuration diagram of the fundus camera of the second embodiment. The same reference numerals as those in FIG. 1 of the first embodiment denote the same members.

  Instead of the visible LED 22b and the infrared LED 22c of the alignment index unit 22, a two-color LED 22d is arranged and moves together with the light guide 22a.

  With this configuration, since the two-color LED 22d can selectively emit two wavelengths of light, it is not necessary to switch the position between the visible LED 22b and the infrared LED 22c, and the optical path length due to the color difference is the two-color LED 22d and the light guide 22a. Adjust by moving.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

DESCRIPTION OF SYMBOLS 1 Halogen lamp 2 Objective lens 3 Xenon lamp 5 Dichroic mirror 7 Prism unit 9 Perforated mirror 10 Infrared LED
15 Focus lens 17 Image sensor 22 Alignment index unit 22a Light guide 22b Visible LED
22c Infrared LED
22d two-color LED
25 Focus adjustment knob 27 Observation light source selection switch

Claims (12)

An imaging optical system that forms an image on the imaging means of the return light from the eye to be illuminated illuminated through the illumination optical system;
Selecting means for selecting a wavelength of alignment index light indicating a positional relationship between the photographing optical system and the eye to be examined in an optical axis direction of the photographing optical system;
Index projection means for projecting the alignment index light of the selected wavelength onto the eye to be examined,
The ophthalmic apparatus is characterized in that the photographing optical system is configured such that an optical path length difference corresponding to a wavelength difference of alignment index light projected onto the eye to be examined by the index projection unit is adjusted. Moving means for moving the index projection means along the optical axis of the imaging optical system;
Control means for controlling the moving means so that the optical path length difference is adjusted according to the selection by the wavelength means;
The ophthalmic apparatus according to claim 1, further comprising:   3. The control unit according to claim 2, wherein the control unit controls the moving unit to move the index projection unit to a position on the optical axis of the photographing optical system corresponding to the selected wavelength. Ophthalmic equipment. An imaging optical system that forms an image on the imaging means of the return light from the eye to be illuminated illuminated through the illumination optical system;
Selecting means for selecting a wavelength of alignment index light indicating a positional relationship between the photographing optical system and the eye to be examined in an optical axis direction of the photographing optical system;
Index projection means for projecting the alignment index light of the selected wavelength onto the eye to be examined;
Control means for moving the index projection means to a position on the optical axis of the photographing optical system corresponding to the selected wavelength in response to selection by the selection means;
An ophthalmologic apparatus comprising: The selection means selects any one of a plurality of modes including a non-mydriatic mode for observing the eye to be examined with infrared light and a mydriatic mode for observing the eye to be examined with visible light,
The index projection means projects infrared alignment index light onto the eye when the non-mydriatic mode is selected, and displays visible alignment index light when the mydriatic mode is selected. The ophthalmologic apparatus according to claim 1, wherein the ophthalmologic apparatus projects onto the eye to be examined. An infrared LED for generating the infrared alignment index light;
A visible LED for generating the visible alignment index light;
The ophthalmic apparatus according to claim 5, further comprising: It further has a perforated mirror provided in the photographing optical system,
The said index projection means projects the alignment index light of the said selected wavelength on the said to-be-tested eye through the hole part of the said perforated mirror, The any one of Claim 1 thru | or 6 characterized by the above-mentioned. Ophthalmic equipment. A moving means for moving the emitting portion of the index projection means provided in the hole in the optical axis direction of the photographing optical system;
The ophthalmologic apparatus according to claim 7, wherein the control unit controls the moving unit according to the selection of the selection unit. The selection means selects a wavelength of illumination light that illuminates the eye to be examined through the illumination optical system,
9. The index projection unit projects the alignment index light having a wavelength corresponding to the selected wavelength onto the eye to be examined in accordance with the selection by the selection unit. An ophthalmic device according to claim 1. Selects the wavelength of the alignment index light indicating the positional relationship between the imaging optical system and the eye to be examined in the optical axis direction of the imaging optical system that forms an image on the imaging means of the return light illuminated through the illumination optical system. And a process of
In response to the selection in the selecting step, an index projection means for projecting the alignment index light of the selected wavelength onto the eye to be examined is placed at a position on the optical axis of the imaging optical system corresponding to the selected wavelength. A moving process;
An ophthalmic method characterized by comprising: In the selecting step, any one of a plurality of modes including a non-mydriatic mode in which the eye to be examined is observed with infrared light and a mydriatic mode in which the eye to be examined is observed with visible light is selected,
When the non-mydriatic mode is selected, the index projection unit projects infrared alignment index light onto the eye to be examined. When the mydriatic mode is selected, the index projection unit projects visible alignment. The ophthalmologic method according to claim 10, wherein the index light is projected onto the eye to be examined. A program for causing a computer to execute each step of the ophthalmic method according to claim 10 or 11.

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