JP2001275973A - Ophthalmologic appliance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ophthalmologic appliance capable of suppressing an injury to an eye as much as possible by rapidly avoiding a contact of the apparatus with an eye to be examined. SOLUTION: The ophthalmologic appliance aligns a measuring unit to the eye to be examined. The appliance comprises a moving means for longitudinally moving the measuring unit with respect to the eye to be measured via a transmission mechanism for transmitting a drive force of a motor, an energizing means for energizing the unit rearward, a detecting means for detecting that the unit approaches at a predetermined distance or less with respect to the eye, and a drive force disconnecting means for disconnecting the transmission of the force by isolating a part of the mechanism based on the detected result of the detecting means. In this case, when the transmission of the force of the motor is disconnected by the mechanism, the unit is moved rearward by an energizing force of the energizing means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus for performing examination or measurement by aligning an apparatus with a subject eye in a predetermined positional relationship.

[0002]

2. Description of the Related Art In an ophthalmologic apparatus such as a non-contact tonometer, it is necessary to adjust the alignment of a measuring section with respect to an eye to be examined in a predetermined positional relationship. The alignment adjustment was performed by the examiner using a joystick or the like, but in recent years, in addition to the manual operation of the joystick by the examiner, an auto alignment mechanism that drives and controls the motor that moves the measurement unit based on the detection result of the alignment state A device having the following has also been proposed.

[0003] In an apparatus in which the working distance of the measuring unit to the eye to be examined is relatively short, special care must be taken so that the measuring unit does not come into contact with the eye to be examined. For this reason, when the measurement unit comes too close to the eye to be examined, a mechanism that stops the movement of the measurement unit or that retracts the measurement unit by reversely rotating the motor in a motor driven alignment mechanism has been proposed. .

[0004]

However, when the examinee's face is not fixed so fast that the examinee's eyes move suddenly or the examiner moves the measuring section suddenly by manual operation of the joystick, the measurement by motor drive is performed. Evacuation of the unit may take time and avoiding contact may not be sufficient.

SUMMARY OF THE INVENTION In view of the above prior art, an object of the present invention is to provide an ophthalmologic apparatus capable of quickly avoiding contact of the apparatus with an eye to be examined and minimizing damage to the eye.

[0006]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) In an ophthalmologic apparatus for aligning a measuring section with respect to an eye to be examined, a moving means for moving the measuring section back and forth with respect to the eye to be examined via a transmission mechanism for transmitting a driving force of a motor; An urging means for urging the measuring section backward, a detecting means for detecting that the measuring section has approached a predetermined distance or more with respect to the eye to be examined, and the transmitting mechanism based on a detection result of the detecting means. A driving force cutting unit that cuts off the transmission of the driving force by separating a part thereof, and when the transmission of the driving force of the motor is cut off by the transmission mechanism, the urging force of the urging unit moves the measurement unit backward. It is characterized in that it is configured to move.

(2) The ophthalmologic apparatus of (1) further includes an alignment detecting means for detecting an alignment state of the measuring unit in the front-back direction with respect to the eye to be inspected, and a motor control means for controlling the driving of the motor based on the detection result. And the following.

(3) The ophthalmologic apparatus according to (1) further includes alignment detecting means for detecting an alignment state of the measuring unit in the front-rear direction with respect to the eye to be examined, and the detecting means also serves as the alignment detecting means. And

(4) The ophthalmologic apparatus according to (1) further includes alignment detecting means for detecting an alignment state of the measuring unit in the front-rear direction with respect to the eye to be inspected, and the detecting means is provided separately from the alignment detecting means. It is characterized by.

(5) In the ophthalmologic apparatus of (1), the transmission means has a pinion rack mechanism, and the driving force cutting means is a mechanism for pulling the pinion away from the rack.

(6) In an ophthalmologic apparatus for aligning a measurement unit with an eye to be examined, a moving means for moving the measurement unit back and forth with respect to the eye to be examined via a transmission mechanism for transmitting a driving force of a motor; Detecting means for detecting that the measuring unit has approached a predetermined distance or more with respect to the optometry, and a drive for cutting off transmission of driving force by separating a part of the transmission mechanism based on a detection result of the detecting means It is characterized by comprising a force cutting means, and an urging means for applying a rearward urging force to the measuring unit such that the measuring unit is not moved when the driving force is transmitted.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

[Overall Configuration] FIG. 1 is a schematic external view of a non-contact tonometer according to an embodiment. Reference numeral 1 denotes a base, on which a face support 2 for supporting the face of the subject is fixed.
The face support 2 includes a chin rest 2a on which the subject's chin is placed, and a forehead rest 2b for applying a forehead. At the time of measurement, the subject's eye is fixed by bringing the subject's face into contact with the chin rest 2a and the forehead rest 2b.

Reference numeral 3 denotes a main body, reference numeral 4 denotes a measuring unit containing a measuring mechanism and an alignment optical system described later, and reference numeral 5 denotes a main body 3
And a joystick for moving the measuring unit 4.
By operating the joystick 5, the main body 3 slides on the horizontal plane of the base 1 in the front-back direction (Z direction) and the left-right direction (X direction). In addition, the operation of the rotation knob 5a causes the measurement unit 4 to operate.
Moves in the vertical direction (Y direction) with respect to the main body 3. Further, when the automatic alignment mode is selected, the measuring section 4 moves in the XYZ directions with respect to the main body section 3 (moving mechanisms in each direction will be described later).

Reference numeral 6 denotes a nozzle section in which nozzles for ejecting compressed gas toward the eye to be examined are arranged. In addition, the joystick 5 side (examiner side) of the main body 3 has an observation T
A V monitor is provided.

[Structure of Each Part] Next, the structure of the main elements of the apparatus will be described with reference to a joystick mechanism, a Y (up and down) direction moving mechanism of the measuring unit 4, an XZ (horizontal and longitudinal) moving mechanism,
The Z direction reference position / movement limit detection mechanism, left / right eye / rear position detection mechanism, alignment optical system, and control system will be described separately. A non-contact tonometer measures the intraocular pressure of the subject's eye based on the gas pressure directly or indirectly detected by blowing a compressed gas onto the cornea of the subject to deform it into a predetermined shape. However, since the description of the measurement mechanism itself has little relation to the present invention, the description thereof is omitted. For details of the measuring mechanism, see Japanese Patent Application Laid-Open No. 4-297 by the present applicant.
See No. 226 (Title of Invention Noncontact Tonometer).

(A) Joystick Mechanism FIG. 2 is a sectional view of a main part of the base 1 and the main body 3 including a joystick mechanism. The movement of the main body 3 with respect to the base 1 comes into contact with the spherical portion 501 and the lower end portion 502 formed below the shaft 500 of the joystick 5, the sliding plate 503 on which the lower end portion 502 swings, and the sliding plate 503. The configuration of the friction plate 504 attached to the base 1 and the spherical bearing 505 inside the housing 3a integrated with the main body 3 realizes fine movement in the horizontal direction. The vertical movement of the measuring unit 4 with respect to the main body 3 is controlled by the rotation knob 5 on the outer periphery of the joystick 5.
a, and a slit plate 506 that rotates together with the rotation knob 5a
And the light source 507 and the light receiving element 508 provided on the shaft 500 with the slit plate 506 interposed therebetween.
The rotation direction and the amount of rotation of the rotary knob 5a are detected from the signal of, and the measurement unit 4 is moved up and down based on the detection result.
This is performed by controlling the drive of the shaft motor 106.
The details of this joystick mechanism are described in Japanese Patent Application Laid-Open No. 6-7292 filed by the present applicant.

(B) Y (vertical) direction moving mechanism In FIG. 2, 101 is a feed screw, 102 is a feed nut, and the feed nut 102 is Y
It is fixed to the table 100. On the other hand, the feed screw 10
Reference numeral 1 is rotatably held by a housing of the main body 3 via a bearing 104. Gear 1 is located at the lower end of feed screw 101
05 is fixed, and the Y-axis
Gear 107 attached to the rotating shaft of the
05 is engaged. Further, a compression spring 108 is attached between the Y table 100 and the housing of the main body 3, and the compression spring 108 supports the load of the measuring unit 4 mounted on the Y table 100, and Up and down movement is smooth. 1
10 is a guide shaft fixed to the Y-table 100,
By moving along the guide bearing 111 fixed to the housing of the main body 3, the vertical movement of the Y table 100 is guided. With this configuration, when the Y-axis motor 106 is driven to rotate, the measuring unit 4 mounted on the Y table 100 is rotated.
Moves up and down.

(C) XZ (left, right, front and rear) direction moving mechanism FIG. 3 is a view for explaining the XZ direction moving mechanism of the measuring section 4.
In FIG. 3, the X table 200 is arranged along the two rails 201 fixed on the Y table 100 described above.
It is slidably provided in the direction. An X-axis motor 202 is fixed to the Y-table 100, and the rotation axis of the X-axis motor 202 and the X-table 200 are connected via a link 203. The X-axis motor 20 is
2 is transmitted and transmitted as the movement of the X table 200 in the X direction.

The X table 200 has 2 extending in the Z direction.
Each of the rails 211 is fixed, and a Z table 210 is provided along the rail 211 so as to be slidable in the Z direction. Motor support 218 fixed to X table 200
a, a Z-axis motor 212 is attached to the
An electromagnetic clutch 213 is attached to a clutch support base 218b fixed to 18a. The rotation shaft of the Z-axis motor 212 is coupled to the input shaft of the electromagnetic clutch 213, and the pinion 214 is mounted on the output shaft 213a of the electromagnetic clutch 213. And pinion 2
14 is a rack 215 screwed to the Z table 210
Is engaged. When the electromagnetic clutch 213 is energized, its input shaft and output shaft 213a are directly connected, and the Z-axis motor 212
Is transmitted to the pinion 214, and the Z table 210 is moved in the Z direction. Conversely, the electromagnetic clutch 2
When the power supply to the electromagnetic clutch 213 is cut off, the output shaft 213a of the electromagnetic clutch 213 is disconnected from the input shaft, and the transmission of the driving force by the Z-axis motor 212 to the pinion 214 and the rack 215 is cut off. The measuring section 4 is mounted on the Z table 210.

In FIG. 3, a tension spring 217 is hung on a spring support 216 screwed to the Z table 210, and the other end of the tension spring 217 is connected to a motor support 218.
It is stopped on the a side. Therefore, the Z table 210 is moved by the tension spring 217 to the arrow A side (rear side with respect to the eye to be examined).
Always being energized. When the energization to the electromagnetic clutch 213 is turned off, the transmission of the driving force of the Z-axis motor 212 is cut off, so that the Z-table 210 (measuring unit) is moved toward the examiner by the spring force of the tension spring 217. Return instantly. 241
Is a limiting plate when the Z table 210 returns instantaneously due to the spring force of the tension spring 217, and 242 is a cushion for cushioning the impact when the Z table 210 and the limiting plate 241 collide.

The urging force of the tension spring 217 is determined by the rotational load of the reduction gear in the Z-axis motor 212 and the electromagnetic clutch 21.
When the input shaft and the output shaft of No. 3 are directly connected and the driving force is transmitted, the Z table 210 does not move even if the rotation of the motor 212 is stopped. Alternatively, when the driving force of the Z-axis motor 212 is in the transmitting state, the Z-table 2 is driven by a force equivalent to the urging force of the tension spring 217.
A current may be supplied to the motor 212 so that the motor 10 does not move.

(D) XZ direction reference position / movement limit detection mechanism In FIG. 3, 230a and 230b are X tables 200.
A photo sensor 231 is provided above, and 231 is a light shielding plate fixed to the Z table 210. The sensor 230a is connected to the Z table 210 by the light shielding state of the light shielding plate 231.
Is detected with respect to the reference position in the Z direction, and it is detected that the Z table 210 is located at the reference position by the timing of switching the light blocking state as shown in FIG. . Further, the notch 231 is formed in the light shielding plate 231.
a is formed, and the sensor 230b detects each of the front and rear movement limits by switching the light blocking state by the cutout portion 231a accompanying the movement of the light blocking plate 231. The reference position in the Z direction is located on the front side of the center of the movable range, and the Z table 210 (that is, the measuring unit 4) is set so as to move 5 mm forward and 20 mm backward with respect to the reference position. I have.

In FIG. 3, reference numerals 220a and 220b denote photosensors provided on the Y table 100.
Reference numeral 1 denotes a light shielding plate fixed to the X table 200. The sensors 220a and 220b have the notch 2 as in the Z direction.
The reference position and the left and right movement limits of the X table 200 in the X direction are detected based on the light shielding state of the light shielding plate 221 having the reference numeral 21a and the switching timing.

Since the moving range in the Y direction is relatively large, the reference position is not provided in the apparatus of the embodiment.
It may be provided in the same manner as in the XZ direction.

(E) Left and right eye / rear position detection mechanism In FIG. 2, reference numeral 300 denotes a micro switch for detecting the rear end (examiner side) held in the main body 3;
The guide plate is fixed to the guide plate. When the main body 3 comes to the rear end of the forward / backward movement by operating the joystick 5, the contact of the microswitch 300 is pushed up to energize. Reference numeral 310 denotes a left / right eye detection microswitch held by the main body 3, and reference numeral 311 denotes a guide plate fixed to the base 1. The guide plate 311 extends in the left-right direction from the examiner's side, and is higher in the right direction (in FIG. 2, the back side of the paper surface) with respect to the center of the base 1 in the left-right direction. The microswitch 310 detects the left and right of the subject's eye according to the ON / OFF state. The detection signals of the micro switches 300 and 310 are used as command signals for returning the measuring unit 4 to the reference position.

(F) Optical System FIG. 5 is a schematic configuration diagram of the alignment optical system housed in the measuring section 4 when viewed from above. On the optical axis L1 of the observation optical system 10, a nozzle 9 for ejecting a gas for deforming the cornea is disposed while being held by the glass plates 8a and 8b.
1 matches. A beam splitter 11, an objective lens 12, a beam splitter 14, a filter 15, and a CCD camera 16 are arranged on the optical axis L1. The observation optical system 10 is used for alignment indices in up, down, left, and right directions (described later).
Also serves as an index detection optical system for detecting the Filter 15
It has the property of transmitting light source 31 (wavelength 950 nm) and being impervious to visible light and the index light beam (wavelength 800 nm) of light source 51, thereby preventing unnecessary noise light from entering CCD camera 16. . The anterior eye image and the index image captured by the CCD camera 16 are displayed on a TV monitor 17.

Reference numeral 25 denotes a fixation optical system, and a light beam emitted from the fixation target plate 27 when the fixation target plate 27 of the light source 26 is turned on is
Projection lens 28, beam splitter 14, objective lens 1
2. Through the beam splitter 11, the light enters the eye to be examined through the nozzle 9.

Reference numeral 30 denotes an alignment target projection optical system. The infrared light having a wavelength of 950 nm emitted from the light source 31 is converted into a parallel light by the projection lens 32, reflected by the beam splitter 11, passes through the nozzle 9 along the optical axis L1, and travels toward the cornea Ec to be examined. The light beam specularly reflected by the cornea Ec forms an index i1 which is a virtual image of the light source 31. The light flux of the index i1 is transmitted through the observation optical system 10 to the CCD.
The light enters the camera 16 and forms an image on the image sensor of the CCD camera 16.

Reference numeral 50 denotes a distance index projection optical system, and reference numeral 60 denotes a detection optical system. The optical axis L2 of the distance index projection optical system 50 and the optical axis L3 of the distance index detection optical system 60 are equal to the optical axis L1.
And intersect at a position separated from the nozzle 9 by a predetermined working distance. The light having a wavelength of 800 nm emitted from the light source 51 is converted into a parallel light beam by the projection lens 52, and is irradiated on the cornea Ec along the optical axis L2, and the index i6
To form The light flux of the index i6 enters the one-dimensional detection element 63 via the light receiving lens 61 and the filter 62. The filter 62 has a characteristic of transmitting the light flux (wavelength 800 nm) of the light source 51 and having no transmission property with respect to the light flux (wavelength of 950 nm) of the light source 31, and prevents the incidence of noise light on the one-dimensional detection element 63.

(G) Control system FIG. 6 is a configuration diagram of a main part of a control system of the apparatus. 70 is a control circuit, 71 is an image processing circuit, 72 is a distance index detection processing circuit, 80 is a measurement system, 81 is a display circuit for generating character information and a reticle, and 82 is a combining circuit. Reference numeral 83 denotes a switch unit, which is an alignment mode for selecting whether the alignment is to be performed by the apparatus based on the detection of the index or by the examiner using only the joystick 5.
A switch 86 for clearing measurement data, and a print switch 86 for printing out the measurement result from the printer 90.

The image processing circuit 71 performs image processing on the captured image from the CCD camera 16 and inputs the processing result to the control circuit 70. The control circuit 70 obtains the position information of the target image from the input signal. Further, the control circuit 70 controls the one-dimensional detection element 63 input through the detection processing circuit 72.
, The information on the deviation in the front-back direction with respect to the eye E is obtained. The deviation information obtained by the control circuit 70 is displayed on the display circuit 81.
The display circuit 81 generates a figure signal of a distance mark and a position signal on the TV monitor 17 based on the information. The output signal from the display circuit 81 is combined with the video signal from the CCD camera 16 by the combining circuit 82,
It is output on the monitor 17.

FIG. 7 is a view showing an example of a screen displayed on the TV monitor 17 when the alignment is performed in a proper state in the XY directions. In a state where the X and Y directions are aligned properly, an index image i10 formed near the center of the cornea by the alignment index projection optical system is projected. 41
Indicates a reticle image formed by a reticle optical system (not shown) (the reticle image 41 can also be formed electrically). Reference numeral 42 denotes a distance mark, and the distance mark 42 corresponds to the distance between the cornea of the eye to be inspected and the nozzle section 6.
1 moves in real time up and down, and overlaps the reticle image 41 when the cornea is at the proper working distance.

In an apparatus having the above configuration,
The operation in the automatic alignment mode will be described.

The examiner operates the joystick 5 and the like while observing the TV monitor 17 to roughly align the measuring unit 4 with the eye to be examined (at the start of the measurement, the measuring unit 4
Is located at the reference position in the XZ direction). The coarse alignment is performed by adjusting the X and Y directions so that the target image formed by the alignment target projection optical system appears on the TV monitor 17, and adjusting the eye to be inspected so that the target image (anterior eye image) appearing on the screen is in focus. The main body 3 is moved toward.

The control circuit 70 determines the alignment state in the X and Y directions based on the positional relationship of the index image detected and processed by the image processing circuit 71. Based on the determination result, the index image i10 falls within a predetermined allowable range. The measuring unit 4 is moved by driving the X-axis motor 202 and the Y-axis motor 106 so as to enter the position. Further, when the light flux of the index i6 enters the one-dimensional detection element 63, the control circuit 70 obtains the shift information in the Z direction based on the signal from the one-dimensional detection element 63, and based on the shift information, the Z-axis. The motor 212 is driven to move the measuring unit 4, and automatic alignment is performed.

The control circuit 70 includes a one-dimensional detection element 63
The eye to be inspected and the nozzle portion 6 are at least a predetermined approach distance based on a signal from the camera (for example, the distance between the eye to be inspected and the nozzle portion 6 is 5 mm).
) Is monitored for too close. Here, the fixation of the face of the subject to the face support unit 2 is shallow, and the subject's eye suddenly approaches the measuring unit 4 side, or the examiner moves the measuring unit 4 to the subject's eye side by operating the joystick. When the eye 6 is too close to the nozzle 6 and it is detected that the nozzle 6 has approached a predetermined distance or more, the control circuit 70 cuts off the power supply to the electromagnetic clutch 213. When the power supply to the electromagnetic clutch 213 is turned off, the driving force of the Z-axis motor 212 is not transmitted to the pinion 214, and the rotation of the pinion 214 becomes free. It moves instantaneously in the direction in which the spring contracts due to the force. That is, the measuring unit 4 is instantaneously moved rearward (examiner side) to a position where the Z table 210 contacts the cushion 242. As a result, the possibility that the eye to be inspected comes into contact with the nozzle unit 6 is reduced in the Z-axis mode.
This is avoided more quickly than rotating the motor 212 in the reverse direction. Further, since the transmission of the driving force of the Z-axis motor 212 is cut off and the rearward movement of the measuring unit 4 is free, even if the eye to be inspected comes into contact with the nozzle 6, injury to the eye to be inspected may occur. Can be extremely reduced.

Further, since the retreating movement of the measuring section 4 is performed without using the Z-axis motor 212, even if the alignment driving motor 212 is out of order, the measuring section 4 can be more reliably moved to the eye to be examined. Contact can be avoided.

The means for detecting that the nozzle section 6 of the measuring section 4 has approached the eye to be examined more than a predetermined approach distance includes a distance index projection optical system 50 for detecting alignment in the front-rear direction (working distance). And the distance index detection optical system 60 is shared, but an independent detection system may be provided. in this case,
In addition to providing an optical system similar to the distance index projection optical system 50 and the distance index detection optical system 60, the distance index projection optical system 50 and the distance index detection optical system 60 may be configured by an ultrasonic sensor or the like.

The fact that the measuring section 4 has moved backward is displayed as a message on the TV monitor 17 together with a warning sound, so that the examiner operates the joystick 5 to move the main body 3 on the base 1 backward. The measurement unit 4 is set at a position sufficiently separated from the eye to be examined. When the main body 3 is moved to the rear end,
This is detected by the microswitch 300. The control circuit 70 issues a return command signal according to the detection signal from the microswitch 300, and moves the measuring unit 4 to the reference position. That is, the control circuit 70 energizes the electromagnetic clutch 213 so that the driving force of the Z-axis
14, the Z-axis motor 212 is driven to move the measuring unit 4 forward, and the photo sensor 230a
The measurement unit 4 is positioned at the reference position in the Z direction detected by the measurement.

The return command signal for energizing the electromagnetic clutch 213 and moving the measuring section 4 to the reference position also uses a clear switch 85, a left / right switching signal, and the like.

The fact that the measuring section 4 has returned to the reference position is determined by the TV.
The message is displayed on the monitor 17 as a message. The examiner performs the alignment adjustment again from the operation of the joystick 5 again. The control circuit 70 activates the automatic alignment based on the detection result of the alignment index image, and when the alignment in the XYZ directions is in an appropriate state, stops the movement of the measuring unit 4 and automatically issues a measurement start signal. Measurement system 80
Perform the measurement by. The measurement result is displayed on the TV monitor 17.

The automatic alignment mode has been described above as an example. Of course, even in the manual mode, if it is detected that the eye to be inspected and the nozzle section 6 have approached a predetermined approaching distance or more, the control circuit 70 turns off the electromagnetic circuit. The power supply to the clutch 213 is cut off, and the measuring unit 4 is moved backward. When the manual mode is selected by the alignment mode switch 84, the control circuit 70 moves the measuring unit 4 to the reference position in the XZ direction.
Is moved. Thereby, the retreating movement of the measuring unit 4 to the rear becomes possible.

As described above, the electromagnetic clutch is used as a means for cutting off the transmission of the driving force by the motor 212. However, as shown in FIG. 8, it is also possible to use a solenoid.
Note that the same components as those in the previous example are denoted by the same reference numerals.

The driving force of the motor 212 attached to the motor support 218a is transmitted from the gear 252 attached to the motor shaft 212a to the pinion 253 and the rack 215, and moves the Z table 210. 251 is a pinion shaft 2
A pinion support base 53 rotatably holds 53a, and is rotatably attached to motor shaft 212a via a bearing (not shown). Reference numeral 254 denotes a solenoid, which is a motor support base 218.
a through a solenoid support 255. The tip 254b of the solenoid shaft 254a has a U-shape, and pins 254b are provided at both ends of the U-shape.
Has been fixed. The pin 254b is a pinion support base 251.
The solenoid shaft 254a and the pinion support 251 are connected to each other. Also, the tip 254b and the solenoid 25
4, a compression spring 256 is fitted, and
An urging force is applied so as to always press the pinion 253 against the rack 215 via the pinion support base 251.

In such a configuration, when the power to the solenoid 254 is turned on under the control of the control circuit 70, the solenoid shaft 254a overcomes the spring force of the compression spring 256 and is attracted by the solenoid 254, so that the pinion 25
3 is removed from the rack 215, the motor 212
The transmission of the driving force is cut off. Thereby, the rearward movement of the Z table 210 becomes free, and the tension spring 217
The Z-table 210 (measuring unit 4) moves backward instantaneously due to the spring force of.

When returning the measuring section 4 to the reference position again, the control circuit 70 controls the microswitch 300 and the clear switch 8
The power to the solenoid 254 is turned off by the return command signal from the fifth and the like, and the pinion 253 is again connected to the rack 215 so as to mesh with it, so that the driving force of the motor 212 is transmitted to the rack 215.

[0049]

As described above, according to the present invention,
When the device is too close to the eye to be examined, contact between the eye and the device can be quickly avoided. Further, even if the apparatus comes into contact with the apparatus, it is possible to minimize the damage to the eyes.

[Brief description of the drawings]

FIG. 1 is a schematic external view of a non-contact tonometer according to an embodiment.

FIG. 2 is a cross-sectional view of main parts of a base and a main body including a joystick mechanism.

FIG. 3 is a view for explaining an XZ direction moving mechanism and a retreating mechanism arranged inside a measuring unit.

FIG. 4 is a diagram illustrating a state of a photosensor and a light shielding plate when detecting a reference position in the Z direction.

FIG. 5 is a schematic configuration diagram when an alignment optical system housed in a measurement unit is viewed from above.

FIG. 6 is a configuration diagram of a main part of a control system of the apparatus.

FIG. 7 is a diagram showing an example of a screen displayed on the TV monitor 17 when alignment is performed in a proper state in the XY directions.

FIG. 8 is a view for explaining an XZ direction moving mechanism and a retreat mechanism arranged inside a measuring unit.

[Explanation of symbols]

 4 Measurement Unit 5 Joystick 50 Distance Index Projection Optical System 60 Distance Index Detection Optical System 70 Control Circuit 210 Z Table 211 Rail 212 Z-Axis Motor 213 Electromagnetic Clutch 214 Pinion 215 Rack 217 Tension Spring 251 Pinion Shaft Support 252 Gear 253 Pinion 254 Solenoid 256 compression spring

Claims (6)

[Claims] 1. An ophthalmologic apparatus for aligning a measurement unit with an eye to be examined, a moving unit for moving the measurement unit back and forth with respect to the eye to be examined via a transmission mechanism for transmitting a driving force of a motor, and Biasing means for biasing the portion backward;
Detecting means for detecting that the measuring unit has approached a predetermined distance or more with respect to the eye to be inspected, and cutting off transmission of the driving force by separating a part of the transmission mechanism based on a detection result of the detecting means An ophthalmologic apparatus, comprising: driving force cutting means; wherein the measuring unit is moved backward by the urging force of the urging means when the transmission of the motor driving force is cut off by the transmission mechanism. 2. The ophthalmologic apparatus according to claim 1, further comprising: an alignment detecting unit configured to detect an alignment state of the measuring unit in a front-rear direction with respect to an eye to be inspected; and a motor control unit configured to drive and control the motor based on the detection result. An ophthalmologic apparatus comprising: 3. The ophthalmologic apparatus according to claim 1, further comprising alignment detecting means for detecting an alignment state of said measuring unit in a front-back direction with respect to an eye to be inspected, wherein said detecting means also serves as said alignment detecting means. Ophthalmic equipment. 4. The ophthalmologic apparatus according to claim 1, further comprising alignment detecting means for detecting an alignment state of the measuring unit in the front-rear direction with respect to the eye to be examined, wherein the detecting means is provided separately from the alignment detecting means. Ophthalmic equipment characterized. 5. The ophthalmologic apparatus according to claim 1, wherein said transmission means has a pinion rack mechanism, and said driving force cutting means is a mechanism for pulling the pinion away from the rack. 6. An ophthalmologic apparatus for aligning a measurement unit with an eye to be examined, a moving means for moving the measurement unit back and forth with respect to the eye to be examined via a transmission mechanism for transmitting a driving force of a motor, and an eye to be examined. Detecting means for detecting that the measuring unit has approached a predetermined distance or more, and a driving force for cutting off transmission of driving force by separating a part of the transmission mechanism based on a detection result of the detecting means. An ophthalmologic apparatus comprising: a cutting unit; and an urging unit that applies a rearward urging force to the measuring unit such that the measuring unit does not move when the driving force is transmitted.