JP4168533B2 - Ophthalmic device positioning mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the positional relationship with the eye to be inspected, the present invention is mainly set at a predetermined standby position suitable for operation preparation of the main optical system (including an illumination optical system, a photographing optical system, an alignment optical system, and a focusing optical system). The present invention relates to an ophthalmologic apparatus capable of waiting an optical system.
[0002]
[Prior art]
An ophthalmologic photographing apparatus that photographs the cornea, fundus, and the like of a subject's eye is a type of ophthalmic apparatus. For example, in such an ophthalmologic photographing apparatus, the head of the subject is brought into contact with the facepiece attached to the apparatus and supported so that the head does not move, and then the illumination by the illumination optical system and the photographing by the photographing optical system are performed. And is made. The face is made up of a forehead and an chin table, and the subject places the forehead on the forehead and places the chin on the chin table. In this way, with the head fixed to some extent, the start switch of the apparatus is pushed. Then, alignment with respect to the eye to be examined of the photographing optical system is automatically performed. At the same time, the working distance is adjusted (also called a focusing operation). Working distance adjustment means that the imaging optical system is gradually driven forward (Z-axis direction driving) from the rearmost part toward the eye to be examined, and the imaging optical system is in an operating position with respect to the eye to be examined (the examination part of the eye to be examined of the imaging optical system). To the position where the photographing optical system is in focus. The alignment means that the optical axis of the photographing optical system or the observation optical system in the ophthalmologic photographing apparatus coincides with the examined portion of the eye to be examined. Align left and right.
[0003]
An ophthalmologic photographing apparatus that automatically performs such alignment and working distance adjustment is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 8-206080 and 9-327439.
[0004]
[Problems to be solved by the invention]
However, even if an ophthalmologic photographing apparatus having a function of automatically adjusting the working distance is used, it takes a considerable time to adjust the working distance. The position of the eye to be examined on the subject's head varies depending on the subject. For example, the distance between the forehead and the eyeball in the Z-axis direction is generally greatly different between Westerners and Orientals. If the forehead is attached to the forehead and the head is fixed, a large difference can be made in the forward drive time of the imaging optical system for detecting the illumination light reflection image for alignment and for adjusting the working distance. Therefore, depending on the subject, a considerable amount of time may be required. While the device is working distance adjustment, the subject needs to remain in tension. For example, while the imaging optical system is driven in the optical axis direction of the eye to be examined (Z-axis direction) for adjusting the working distance, the subject can move with the head fixed against the face of the apparatus. I can't blink and I can't blink. In this way, a mental burden is imposed on the subject.
[0005]
The present invention has been made to solve such a problem, and an object thereof is to provide a positioning mechanism for an ophthalmologic apparatus that does not require a long time for focusing or alignment due to a difference in the shape of the face of a subject. .
[0006]
[Means for Solving the Problems]
The positioning mechanism of the ophthalmic apparatus of the present invention is
An alignment optical system that irradiates light from the front to the anterior ocular segment of the eye to be detected and detects an image reflected by the anterior ocular segment, and irradiates light to the anterior ocular segment from an angle and detects the reflected light from the opposite side. A focusing optical system, and driving means for moving the main optical system having the alignment optical system and the focusing optical system with respect to the eye to be examined.
When the standby position of the main optical system is set to an intermediate position between the front and rear strokes of the main optical system, and the anterior segment reflection image is not detected at the start of operation, the driving means advances the main optical system, and the anterior eye When the partial reflection image is detected, the driving means is configured to move backward from the main optical system and advance from the point when the anterior eye reflection image is no longer detected.
[0007]
With this configuration, it is not necessary to move the main optical system from the last part of the front and rear strokes during alignment and focusing as in the prior art, and the movement time is short. That is, alignment and focusing are performed much faster than before.
[0008]
That is, when the amount of light received by the anterior segment is greater than or equal to the threshold value, the main optical system is temporarily retracted to a position that is less than the threshold value and then continuously advanced. It is preferable that a photographing instruction is given when a peak of reflected light from an oblique direction (reflected light from the corneal endothelium) is detected by the focusing optical system. Also, when the amount of reflected image received by the anterior segment is less than the threshold value, the main optical system is advanced as it is, and when it exceeds the threshold value, an imaging instruction is given when the peak of reflected light from an oblique direction is detected. Is preferably performed.
[0009]
In addition, the other positioning mechanism of the present invention is
A subject detection mechanism for transmitting a detection signal to the subject's face and detecting the reflected signal, and irradiating the anterior eye portion of the subject's eye obliquely and detecting the reflected light from the opposite side A focusing optical system, a main optical system including the focusing optical system, and a driving means for moving the subject detection mechanism with respect to the eye to be examined.
The standby position of the main optical system is set to an intermediate position between the front and rear strokes of the main optical system, and when the subject is not detected at the start of operation, the driving means moves the main optical system forward to move the subject. When it is detected, the driving means is configured to move backward from the main optical system so as to move forward from the time when the subject is no longer detected.
[0010]
Therefore, unlike the positioning mechanism, the moving direction of the main optical system is determined by the presence or absence of direct subject detection instead of the detection of the Purkinje image. As a result, the same effect as the positioning mechanism is achieved.
[0011]
The intermediate position is not particularly limited to a half position (center position) of the front / rear stroke.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The positioning mechanism of the ophthalmologic apparatus of the present invention will be described based on the embodiment shown in the accompanying drawings.
[0013]
FIG. 1 is a schematic layout diagram showing a corneal endothelium imaging apparatus to which an embodiment of a positioning mechanism of an ophthalmic apparatus according to the present invention is applied.
[0014]
As shown, the positioning mechanism 1 includes an alignment optical system 2, a focusing optical system 3, and a drive mechanism (not shown).
[0015]
The alignment optical system 2 includes an alignment light irradiation optical system 5 for irradiating parallel light to the eye E, and an anterior ocular segment observation optical system for observing and photographing an anterior ocular segment including a reflection image of alignment light in the anterior ocular segment. 6. The alignment light irradiation optical system 5 includes a light emitting diode 7 that emits alignment index light that is near infrared light, and a collimating lens 8 that converts the alignment index light into parallel rays. The anterior ocular segment observation optical system 6 includes an anterior ocular segment imaging lens 9 and a television camera 10. The anterior segment observed by the television camera 10 includes a reflection image of the alignment index light (a bright spot also called a Purkinje image). Reference numeral 11 denotes a visible light cut filter, and reference numeral 12 denotes a her mirror that transmits infrared light and reflects visible light.
[0016]
When the anterior eye part of the eye E is imaged by the alignment optical system 2, the received image signal obtained by the television camera 10 is input to an image input / output control circuit (not shown), and a monitor screen D (FIG. 2) is received by a video signal from this circuit. ) Displays the anterior segment. On the monitor screen of the television camera 10, a bright spot, which is a Purkinje image P, is observed at a position corresponding to the optical axis A <b> 6 of the anterior segment observation optical system 6 in the anterior segment image. The optical axis of the television camera 10 (set at the center of the monitor screen) is matched with the optical axis A6 of the anterior ocular segment observation optical system 6. The XY direction position control circuit (alignment control circuit) (not shown) that receives the signal from the image input / output control circuit detects the Purkinje image P, and as shown in FIG. The main optical system arrangement portion B is moved in the X direction and the Y direction so as to coincide with the optical axis of the camera 10. The alignment is performed when the alignment control circuit detects that the Purkinje image P and the center O of the screen coincide with each other.
[0017]
Next, the focusing optical system 3 detects the reflected light of the slit light from the focusing light irradiation optical system 13 for irradiating the subject eye E with the slit light from obliquely forward and the diagonally forward side opposite to the subject eye E. And an in-focus detection optical system 14. The focusing light irradiation optical system 13 includes a focusing lamp 15, a visible light cut filter 16, a slit 17, a half mirror 18, and a projection lens 19. The focus detection optical system 14 includes an objective lens 20, a half mirror 21, a focus slit 22, and a focus detection light receiving element 23. As shown in the figure, the focusing light irradiation optical system 13 and the focusing detection optical system 14 intersect at a predetermined angle. This is because the slit light for focusing needs to be reflected so as to form the predetermined angle in order to pass through the focusing slit 22 so that the front surface of the eye to be examined comes to the reflection position. This is for fixing the eye to be examined. And this predetermined reflection position is made to correspond with the focus F of the corneal endothelium imaging | photography optical system 25 mentioned later.
[0018]
The focusing operation is started by moving the main optical system disposition part B forward or backward along the optical axis A6 of the television camera 10 toward the eye E (Z direction). As will be described later, this apparatus is set to wait at an intermediate position of the stroke for focusing, not at the rear end of the stroke in the Z direction. The intermediate position of the Z-direction stroke is the initial position (standby position) during the focusing operation. The slit light from the focusing light irradiation optical system 13 is reflected by the anterior eye portion of the eye E, and the reflected light passes through the focusing slit 22 and is detected by the focus detection light receiving element 23. A light reception signal is input from the focus detection light receiving element 23 to a focus light detection circuit (not shown). Then, a focus signal is sent from the focus light detection circuit to a strobe light emission control circuit (not shown) of the illumination optical system 24 described later. With this signal, the lighting strobe 26 starts to emit light.
[0019]
The apparatus includes the illumination optical system 24 and the corneal endothelium imaging optical system 25. The illumination optical system 24 includes an illumination strobe 26 and a slit diaphragm 27, and illumination light from the strobe 26 passes through the half mirror 18 and then passes along the optical path of the focused light irradiation optical system 13 before the eye E to be examined. It reaches the eye part. The optical path of the corneal endothelium imaging optical system 25 is the same as the optical path of the focus detection optical system 14 up to the half mirror 21. Then, the reflected light of the slit-like illumination light from the anterior eye part is reflected by the half mirror 21, passes through the photographing lens 28, and reaches the television camera 10. By doing so, the corneal endothelial cells of the eye to be examined are photographed by the television camera 10.
[0020]
FIG. 3 shows a situation in which the focus detection light receiving element 23 detects the focus slit light and the TV camera 10 receives the Purkinje image according to the Z direction position of the main optical system disposition portion B. Symbol C1 indicates the corneal epithelium of the eye E, and C2 indicates the corneal endothelium. FIG. 3A shows a state in which the main optical system is behind the focal point with respect to the eye E fixed at a certain reference position. That is, it shows a state where the eye E and the main optical system are too far apart and no Purkinje image is detected. FIG. 3B shows a state in which the main optical system is focused on the eye E to be examined. That is, the Purkinje image is detected as the eye E and the main optical system approach each other. FIG. 3C shows a state in which the main optical system is in front of the focal point with respect to the eye E. In other words, the eye E and the main optical system are too close to each other and the Purkinje image is not detected. In the figure, R1 indicates strong reflected light by the corneal epithelium that can be received by the focus detection light receiving element 23, and R2 indicates weak reflected light by the corneal endothelium. Moreover, the code | symbol L in a figure has shown the light quantity of the Purkinje image which the television camera 10 regarding the position of Z direction can receive. In this apparatus, a threshold value S is set for the amount of light received by the Purkinje image, and if it is greater than this value, it is determined that the Purkinje image has been detected. The direction of movement in the Z direction of the main optical system is made different depending on whether the light amount is equal to or greater than the threshold value S.
[0021]
That is, as shown in FIG. 3B, when the focus detection light receiving element 23 receives the reflected light from the corneal endothelium C2, the focus light irradiation optics so that the light quantity of the Purkinje image is not less than the threshold value S. The crossing angle setting of the optical axes of the system 13 and the focus detection optical system 14 and the focus setting of the anterior ocular segment observation optical system 6 are made. The symbol Q in the figure is a point indicating the amount of light received by the Purkinje image received by the television camera 10. Further, if the main optical system is advanced from the rear end of the stroke toward the eye E, until the received light amount of the Purkinje image by the TV camera 10 is equal to or greater than the threshold value S (Purkinje image detection), The crossing angle setting of the optical axes of the focusing light irradiation optical system 13 and the focusing detection optical system 14 and the focus setting of the anterior ocular segment observation optical system 6 so that the focus detection light receiving element 23 does not receive the reflected light of the corneal epithelium C1. And has been made. As shown in FIG. 3A, the standby position of the main optical system is such that the received light amount of the Purkinje image by the TV camera 10 is less than the threshold value S (Purkinje image not detected), and the focus detection light-receiving element 23 is It is set at a position where the reflected light of the corneal epithelium C1 has not been received yet. The above settings are determined based on a face to be examined having a standard shape (with respect to the shape of the skull and the position of the eyeball).
[0022]
Then, at the standby position of the main optical system, there is a possibility that the state shown in FIG. 3A or the state shown in FIG. As shown in FIG. 3C, the standby position of the main optical system does not become too close to the eye E to be examined. As shown in FIG. 4 (a), a subject whose eyeball is located relatively rearward with respect to the forehead is likely to be in the state shown in FIG. 3 (a). If the subject has an eyeball relatively forward as shown in FIG. 3), the possibility of being in the state shown in FIG. In FIG. 4, reference numeral 31 is a jaw table, and reference numeral 32 is a forehead. Therefore, in this apparatus, when the light reception amount of the Purkinje image is equal to or greater than the threshold value S at the standby position, the main optical system is temporarily retracted to a position where it is less than the threshold value S and then continuously advanced. When the focus detection light receiving element 23 detects the second peak of reflected light (reflected light from the corneal endothelium), an imaging instruction is given. When the Purkinje image received light amount is less than the threshold value S, the main optical system is advanced as it is, and after the threshold light value S is exceeded, the focusing detection light receiving element 23 causes the second peak of reflected light. The camera is instructed to take a picture when it is detected.
[0023]
As described above, the standby position of the main optical system is the intermediate position of the front and rear strokes, but this intermediate position is not limited to the center (1/2 position) of the front and rear strokes. Generally, it is set to any position between the position of 1/6 stroke and the position of 2/3 stroke from the rear end of the front / rear stroke (position farthest from the eye to be examined during the stroke). In particular, the position of 1/3 stroke from the rear end (the point farthest from the eye to be examined during the stroke) is preferable. However, the set position and the settable area may be changed depending on the area where the apparatus is used (West, East, etc.). This is because the average eye position of the subject varies depending on the region. In short, a subject who has an eyeball in a relatively forward position of the face and a subject who has an eyeball in the relatively rearward position should be able to have the same amount of movement of the main optical system for focusing.
[0024]
The above-described jaw table 31 may be movable up and down so that the subject can easily move his / her face, and is detachable so as to be removable according to the shape of the subject's face. Also good. Further, the attachment position of the jaw base 31 to the apparatus frame may be adjustable so that it can be re-fixed by changing in the vertical direction and the horizontal direction.
[0025]
In the above embodiment, the direction of movement of the main optical system for the focusing operation is determined by whether or not a Purkinje image is detected. However, the present invention is not limited to such a configuration. For example, instead of detecting the Purkinje image, the determination may be made based on whether or not a part of the subject's face has been detected. That is, the so-called subject detection mechanism proposed by the applicant of the present application in Japanese Patent Application No. 10-268082 may be used. An example of this subject detection mechanism will be described. As shown in FIG. 5, a subject detection mechanism 33 is disposed at a portion of the present apparatus that faces the subject's face. The subject detection mechanism 33 moves together with the main optical system arrangement part B. The subject detection mechanism 33 detects infrared light from at least the light emitting diode 34 as a subject detection signal transmitting means and the light emitting diode 34 reflected by a part of the subject's face. And a line sensor 35 as a detecting means. In the present embodiment, the infrared light emitted from the light-emitting diode 34 is reflected so that the infrared light emitted from the light-emitting diode 34 is reflected by a portion close to the test portion, such as the eyelid or eyeball of the subject fixed by the jaw table 31 or the forehead support 32 of the apparatus. The direction is determined. The front end position of the detection region of the line sensor 35, that is, the point for detecting the subject for the first time when the main optical system is advanced from the rear end of the stroke toward the eye E to be inspected. The crossing angle setting of the optical axes of the focusing light irradiation optical system 13 and the focusing detection optical system 14 and the setting of the optical axis angle of the subject detection mechanism 33 are performed so that the light receiving element 23 does not receive the reflected light of the corneal epithelium C1. (Similar to FIG. 3A).
[0026]
In the present embodiment, the position of the eye E is detected by the line sensor 35. However, for example, an element such as a position sensor device (PSD) may be used instead of the line sensor.
[0027]
In the above embodiment, the focusing light irradiation optical system 13 and the illumination optical system 24 are disposed on substantially the same optical path, and the focusing detection optical system 14 and the corneal endothelium imaging optical system 25 are substantially the same. Although arranged on the optical path, they are not particularly limited to the same. If the optical axes of the focusing light irradiation optical system 13 and the focusing detection optical system 14 are set as described above, the optical paths of the illumination optical system 24 and the corneal endothelium imaging optical system 25 are different. Also good.
[0028]
【The invention's effect】
According to the positioning mechanism of the ophthalmologic apparatus of the present invention, it is not necessary to move the main optical system from the last part of the front and rear strokes during alignment and focusing as in the prior art, and the movement time is independent of the shape of the subject's face. Is short. That is, alignment and focusing are performed much faster than before.
[Brief description of the drawings]
FIG. 1 is a schematic layout diagram showing a corneal endothelium imaging apparatus to which an embodiment of a positioning mechanism of an ophthalmic apparatus according to the present invention is applied.
FIG. 2 is a front view showing a monitor screen on which an anterior segment of an eye to be examined is displayed.
3A, FIG. 3B, and FIG. 3C are schematic views showing the reflection state of the focusing slit light in the ophthalmologic apparatus of FIG.
FIG. 4 is a schematic side view showing a state during examination of a subject by an ophthalmologic apparatus.
FIG. 5 is a schematic view showing a main part of a corneal endothelium imaging apparatus to which another embodiment of the ophthalmic apparatus positioning mechanism of the present invention is applied.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Positioning mechanism 2 ... Alignment optical system 3 ... Focusing optical system 5 ... Alignment light irradiation optical system 6 ... Anterior ocular segment observation optical system 7 ... Light emitting diode 8 ... Collimating lens 9 ... anterior eye photographing lens 10 ... TV camera 11, 16 ... visible light cut filter 12, 18, 21 ... half mirror 13 ... focusing light irradiation optical system 14 ..Focus detection optical system 15 ... Focus lamp 17 ... Slit 19 ... Projection lens 20 ... Objective lens 22 ... Focus slit 23 ... Focus detection light receiving element 24 ... illumination optical system 25 ... corneal endothelium imaging optical system 26 ... illumination strobe 27 ... slit aperture 28 ... taking lens 31 ... jaw base 32 ... forehead 33 ...・ Subject detection mechanism 34... Light emitting diode 35. Sensor A6 ... optical axis B of the anterior ocular segment observation optical system ... main optical system arrangement part C1 ... corneal epithelium C2 ... corneal endothelium D ... monitor screen E ... eye L to be examined ..Purkinje image light quantity O ... Center P of the monitor screen ... Purkinje image Q ... Reception amount R1 of Purkinje image at the position of the main optical system ... Reflected light R2 at the corneal epithelium ... Corneal endothelium Reflected light

Claims (2)

An alignment optical system that irradiates light from the front to the anterior ocular segment of the eye to be detected and detects an image reflected by the anterior ocular segment, and irradiates light to the anterior ocular segment from an angle and detects the reflected light from the opposite side. A focusing optical system, and driving means for moving the main optical system having the alignment optical system and the focusing optical system with respect to the eye to be examined.
When the standby position of the main optical system is set to an intermediate position between the front and rear strokes of the main optical system, and the anterior segment reflection image is not detected at the start of operation, the driving means advances the main optical system, and the anterior eye A positioning mechanism for an ophthalmologic apparatus configured such that, when a partial reflection image is detected, the driving unit temporarily retracts the main optical system to advance from the point in time when the anterior ocular reflection image is no longer detected. A subject detection mechanism for transmitting a detection signal to the subject's face and detecting the reflected signal, and irradiating the anterior eye portion of the subject's eye obliquely and detecting the reflected light from the opposite side A focusing optical system, a main optical system including the focusing optical system, and a driving means for moving the subject detection mechanism with respect to the eye to be examined.
The standby position of the main optical system is set to an intermediate position between the front and rear strokes of the main optical system, and when the subject is not detected at the start of operation, the driving means moves the main optical system forward to move the subject. A positioning mechanism for an ophthalmologic apparatus configured to advance from the point in time when the driving means retracts the main optical system once and no longer detects the subject during detection.

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