JP2014045921A - Eye refractive power measuring apparatus and calibration method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an eye refractive power measuring apparatus capable of preventing an initialization time from becoming long, and a calibration method for the apparatus.
A measuring optical system that projects a measurement index on the fundus and receives a reflected light beam from the fundus, and an optotype presenting optical system for presenting the optotype to the eye. In an eye refractive power measurement apparatus that objectively measures, a rotating member including an optical member disposed in an optical path of a visual target presenting optical system, a rotation driving mechanism that has a driving source and rotates the rotating member, and a rotating member , A sensor for detecting an origin return signal indicating that the rotating member has returned to the origin position for adjusting the rotational position of the rotating member, and a rotating member disposed at a predetermined initial position as the origin. Rotation position control means for rotating in a predetermined direction until a return signal is detected and adjusting the position of the rotating member with reference to the origin position, and the position of the rotating member corresponding to the origin position is within an error range of the initial position Set to a position outside It is characterized by that.
[Selection] Figure 7

Description

  The present invention relates to an eye refractive power measuring apparatus that measures the eye refractive power of a subject's eye, and a calibration method for the apparatus.

  An eye refractive power measuring device that projects a measurement index onto the fundus of the subject, receives a reflected light beam from the fundus on a light receiving element, and objectively measures the refractive power of the subject's eye based on the output of the light receiving element. Is known (see, for example, Patent Document 1).

  By the way, the eye refractive power measuring device has a correction optical system for correcting astigmatism of the eye to be examined and a target switching mechanism for selectively switching the target to be presented to the eye to be examined, and is aware of the refractive power of the eye to be examined. An apparatus having a function to measure automatically is known (for example, see Patent Documents 2 and 3).

The astigmatism correcting optical system and the target switching mechanism are provided with a rotation drive mechanism, and an origin position return signal is detected by a sensor at the time of initialization related to positioning of a rotating member rotated by the rotation drive mechanism. Note that these require precise positioning.
JP 2004-129711 A JP 59-80227 A JP 2006-280613 A

  However, in the case of the conventional astigmatism correcting optical system and the index presenting optical system, a lot of time may be required until the initialization is completed (for details, refer to the following embodiment).

  In view of the above-described problems of the prior art, it is an object of the present invention to provide an eye refractive power measuring device that can prevent an initialization time from becoming long, and a calibration method for the device.

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

(1) A measurement optical system that projects a measurement index onto the fundus of the subject and receives a reflected light beam from the fundus, and an optotype presenting optical system for presenting the optotype on the eye to be examined. In an eye refractive power measuring apparatus that objectively measures the eye refractive power of a human eye,
A rotating member including an optical member disposed in the optical path of the optotype presenting optical system;
A rotation drive mechanism having a drive source and rotating the rotating member;
A sensor provided in the vicinity of the rotating member for detecting an origin return signal indicating that the rotating member has returned to the origin position for adjusting the rotational position of the rotating member;
The driving source is controlled, the rotating member arranged at a predetermined initial position is rotated in a predetermined direction until an origin return signal is detected by the sensor, and the position of the rotating member is determined based on the detected origin position. Rotational position control means for adjusting
With
The position of the rotating member corresponding to the origin position is set at a position outside the error range of the initial position.
(2) having an operation unit operated by the examiner;
The initialization control means starts driving the drive source for detecting the origin return signal after power is turned on or based on a predetermined operation signal from the operation unit (1) Eye refractive power measurement device.
(3) The eye refractive power measuring apparatus according to (1), wherein a direction approaching the origin position from the initial position is set as a predetermined rotation direction for detecting the origin return signal and stored in a memory. .
(4) Correcting astigmatism of the subject's eye on which the target is presented, having two cylindrical lenses with equal focal lengths arranged rotatably around the optical axis in the optical path of the target presentation optical system Correction optical system for
The rotating member is a lens holding unit that holds the cylindrical lens,
The initial position is a position where an astigmatism power of the two cylindrical lenses is 0D.
(5) The rotating member is an optotype disc plate in which a plurality of chart portions that are selectively arranged in the optical path of the optotype presenting optical system are provided on the same circumference. Eye refractive power measurement device.
(6) The rotational position control means
Moving the rotating member to a temporary position of the initial position;
The rotation member moved to the temporary position is rotated in a predetermined direction until the origin return signal is detected by the sensor, and the origin return signal is detected.
(1) The eye refractive power measurement device according to (1), wherein the rotating member is rotated by an adjustment amount stored in a memory with reference to the detected origin position, and the rotating member is positioned at a true position of the initial position.
(7) a measurement optical system that projects a measurement index on the fundus of the subject and receives a reflected light beam from the fundus; an optotype presenting optical system for presenting the optotype to the eye;
A rotating member including an optical member disposed in an optical path of the visual target presenting optical system, a rotation driving mechanism having a driving source and rotating the rotating member with respect to the visual target presenting optical system, and A sensor provided in the vicinity for detecting an origin return signal indicating that the rotating member has returned to the origin position for adjusting the rotational position of the rotating member;
The driving source is controlled, the rotating member arranged at a predetermined initial position is rotated in a predetermined direction until an origin return signal is detected by the sensor, and the position of the rotating member is determined based on the detected origin position. Rotational position control means for adjusting
A calibration method for an eye refractive power measurement device that objectively measures the eye refractive power of a subject's eye,
In order to check a deviation due to an error when the rotary member position corresponding to the origin position and the initial position coincide with each other, and to detect the origin return signal in the direction approaching the origin position from the initial position A method for calibrating an eye refractive power measuring device, characterized in that it is set as a predetermined rotation direction.

  According to the present invention, the initialization time can be shortened.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. FIG. 1 is an external configuration diagram of an objective eye refractive power measurement apparatus according to this embodiment. The objective eye refracting power measuring apparatus 100 moves to the base 1, the face support unit 2 attached to the base 1, the moving base 3 movably provided on the base 1, and the moving base 3. The measuring unit 4 is provided so as to accommodate an optical system described later. The measuring unit 4 is moved in the left-right direction (X direction), the up-down direction (Y direction), and the front-rear direction (Z direction) with respect to the subject eye E by the driving unit 6 provided on the moving table 3. The movable table 3 is moved on the base 1 in the left-right direction and the front-rear direction by operating the joystick 5. Further, the measurement unit 4 is moved in the vertical direction by the drive of the drive unit 6 by the rotation operation of the rotary knob 5a. On the top of the joystick 5, a measurement start switch 5b is provided. A display monitor 7 is provided on the movable table 3.

  FIG. 2 is a schematic configuration diagram of an optical system and a control system of the apparatus. The eye refractive power measurement optical system 10 includes a projection optical system 10a that projects a spot-like measurement index on the fundus oculi Ef through the center of the pupil of the subject eye E, and fundus reflection light reflected from the fundus oculi Ef. And a light receiving optical system 10b that picks up a ring-shaped fundus reflection image on the imaging element of the two-dimensional light receiving element.

  The projection optical system 10 a includes a measurement light source 11, a relay lens 12, a hall mirror 13, and a measurement objective lens 14 disposed on the optical axis L <b> 1 of the measurement optical system 10. The measurement light source 11 is arranged in a positional relationship optically conjugate with the fundus oculi Ef of the normal eye. The opening of the Hall mirror 13 is optically conjugate with the pupil of the subject's eye E.

  In the light receiving optical system 10b, the objective lens 14 and the hall mirror 13 of the projection optical system 10a are shared, and the relay lens 16 and the total reflection mirror 17 disposed on the optical axis L1 in the reflection direction of the hall mirror 13, and the total reflection mirror. 17 includes a light receiving stop 18, a collimator lens 19, a ring lens 20, and an imaging element 22 that is a two-dimensional light receiving element. The light receiving diaphragm 18 and the image sensor 22 are disposed in a positional relationship optically conjugate with the fundus oculi Ef. The ring lens 20 includes a lens portion in which a cylindrical lens is formed in a ring shape on a transparent flat plate, and a light shielding portion where light is shielded except for the ring-shaped lens portion. The ring lens 20 is optically conjugate with the pupil of the eye E through an optical system from the objective lens 14 to the collimator lens 19. An output from the image sensor 22 is input to the control unit 70. Further, the measurement light source 11 of the projection optical system 10a, the collimator lens 19, the ring lens 20, and the image sensor 22 of the light receiving optical system 10b are integrally moved by the moving mechanism 23 in the optical axis direction. As the eye refractive power measuring optical system 10, a well-known one can be used.

  Between the objective lens 14 and the subject eye E, the target luminous flux from the target presentation optical system 30 is guided to the subject eye E, and the reflected light from the anterior eye part of the subject eye E is observed. A dichroic mirror 29 leading to the optical system 50 is disposed. The dichroic mirror 29 transmits the wavelength of the measurement light beam used in the measurement optical system 10.

  An alignment index projection optical system 40 is disposed in front of the anterior segment of the subject's eye E. The alignment index projection optical system 40 includes a ring index projection optical system 41 that projects a ring index on the cornea of the subject's eye E, an index projection optical system 42 that projects an infinite index of two bright spots on the cornea Ec, Is provided. The index projection optical system 42 is arranged symmetrically with respect to the observation optical axis. The ring index projection optical system 41 is also used as anterior segment illumination that illuminates the anterior segment of the subject's eye E.

  The observation optical system 50 includes an imaging lens 51 and a two-dimensional imaging element 52 arranged on the optical axis in the reflection direction of the half mirror 53. An output from the image sensor 52 is input to the control unit 70. As a result, the anterior segment image of the subject's eye E is captured by the two-dimensional image sensor 52 and displayed on the monitor 7. The observation optical system 50 also serves as an optical system that detects an alignment index image formed on the cornea of the eye E by the alignment index projection optical system 40, and is in an alignment state based on the position detection of the alignment index image by the control unit 70. The suitability is determined.

  The optotype presenting optical system 30 shares the objective lens 39 of the observation optical system 50, and includes a light source 31 such as an LED disposed on the optical axis L <b> 2 coaxial with the optical axis L <b> 1 by the dichroic mirror 29, and a target plate 32. , Relay lens 33 and reflecting mirror 36. The optotype presenting optical system 30 is also used as a refractive power correcting optical system for correcting the refractive power of the subject's eye, and an astigmatism correcting optical system 340 is disposed between the reflecting mirror 36 and the relay lens 33. ing.

  The target plate 32 has a plurality of targets 32a including a fixation target for performing clouding on the subject's eye E during objective refractive power measurement and a visual test for visual acuity used during subjective refractive power measurement. They are arranged on concentric circles. As the visual acuity test target, visual targets for each visual acuity value (visual acuity values 0.1, 0.3,..., 1.5) are prepared. The optotype plate 32 is rotated by a motor 37, and the optotype 32a is switched and disposed on the optical axis L2 of the optotype presenting optical system 30. The target luminous flux of the target 32a illuminated by the light source 31 travels toward the subject's eye E via an optical member from the relay lens 33 to the dichroic mirror 29.

  The light source 31 and the target plate 32 (target 32a) are integrally moved in the direction of the optical axis L2 by a drive mechanism 38 including a motor and a slide mechanism. By moving the light source 31 and the target 32a, the target display position (presentation distance) is optically changed from the distance to the near distance. As a result, cloud is applied to the subject eye E during objective refractive power measurement, and the spherical refractive power of the subject's eye is corrected during subjective refractive power measurement. That is, a correction optical system having a spherical power is configured by the movement of the objective lens 39, the relay lens 33, the light source 31, and the target 32a. The correction optical system having a spherical power may be configured by adding a relay lens that can move in the optical axis direction to the visual target presenting optical system.

  The astigmatism correcting optical system 340 includes two positive cylindrical lenses 340a and 340b having the same focal length. The cylindrical lenses 340a and 340b are independently rotated around the optical axis L2 by driving the rotation mechanisms 350a and 350b, respectively. FIG. 5 is a perspective view showing a part of the astigmatism correcting optical system of the present embodiment. The rotation mechanism 350a includes a motor (for example, a stepping motor) 351, a gear 352, a lens holding portion 353, and a tooth portion 354 provided in the lens holding portion 353. The gear 352 is attached to the rotation shaft of the motor 351 and is disposed so as to mesh with the tooth portion 354. The lens holding portion 353 is supported inside the measurement portion 4 by a rotatable support mechanism (not shown) (for example, a bearing mechanism). And the lens holding | maintenance part 353 supports the cylindrical lens 340a so that rotation is possible centering | focusing on the optical axis L2. When the motor 351 is rotated, power is transmitted from the gear 352 to the tooth portion 354, and the lens holding portion 353 is rotated.

  A sensor 60 is disposed in the vicinity of the lens holding portion 353. The sensor 60 is used as a sensor for detecting an origin return signal indicating that the lens holder 353 has returned to the origin position for adjusting the rotational position of the lens holder 353. The sensor 60 includes a transmission unit 61 and a reception unit 62, and detects the return of the origin of the lens holding unit 353.

  As the sensor 60, for example, an optical sensor including a light projecting unit and a light receiving unit is used. The lens holding portion 353 is provided with light passing holes 355 at two locations, and sensor light can pass therethrough. The sensor 60 detects the origin return signal of the lens holding part only at the position where the two light passing holes 355 overlap on the optical axis L3 of the sensor light.

  The optical axis L3 formed by the sensor 60 preferably does not coincide with the symmetry axis (diameter) of the cross-sectional shape of the lens holding portion 353. In other words, the sensor 60 is preferably provided so that the sensor optical axis L3 is disposed at a position deviated from the optical axis L2. This is because, for example, when the cylindrical lens 340a has an astigmatic axis angle of 80 degrees and 260 degrees.

  The calibration of the apparatus will be described. Since errors occur due to device assembly and component tolerances, it is necessary to calibrate the device to correct astigmatism accurately. As a calibration method, for example, the apparatus is operated so that the astigmatism axes of the cylindrical lens 340a and the cylindrical lens 340b are orthogonal to each other, and whether or not the astigmatism power is 0D (diopter) is measured using a dedicated detection device (jig). To do. If it is not 0D, the apparatus is adjusted to 0D, and the adjustment amount from the signal detection position at that time is stored in the memory 73. Here, the position where the astigmatism power by the cylindrical lens 340a and the cylindrical lens 340b is 0D is set as the initial position.

Prior to performing astigmatism correction, the control unit 70 rotates the lens holding unit 353 by the adjustment amount stored in the memory 73 with the detected origin position as a reference, and moves the cylindrical lens 340a and the cylindrical lens 340b to the initial positions. (Initialization). By such an initialization operation, the cylindrical lens is arranged at the true position of the initial position.
After the initialization operation, the astigmatism correcting optical system is positioned based on the rotation amount and direction from the initial position, and the astigmatism power is given to the eye to be examined.

  Furthermore, if the optical system is displaced due to an impact applied to the apparatus after calibration of the apparatus is completed, an error may occur in the positioning of the optical system. Once an error occurs, positioning is always performed in a shifted state, and astigmatism correction cannot be performed accurately. It is difficult for the examiner to recognize that a positional shift has occurred in the optical system. Therefore, the control unit 70 can eliminate the influence of the positional deviation generated in the optical system by appropriately initializing the optical system (for example, for each inspection).

  A conventional initialization method will be described. At the time of subjective distance vision measurement, the control unit 70 drives the astigmatism correction optical system based on the astigmatism power C and the astigmatism axis angle A of the subject eye obtained by the distance objective power measurement. Correct astigmatism in the subject's eye. At this time, the control unit 70 positions the cylindrical lenses 340a and 340b based on the rotation amount (or the number of steps of the motor) and the direction from the position where the astigmatism power becomes 0D.

  When the subjective visual acuity test is completed, the control unit 70 rotates the lens holding unit 353 to move it to a temporary position of the initial position. When an operation such as printing or data clear is executed, the control unit 70 initializes the astigmatism correcting optical system accordingly. At this time, the control unit 70 rotates the lens holding unit 353 moved to the temporary position in a predetermined direction until the origin return signal is detected by the sensor 60, and detects the origin return signal. Based on the adjustment amount at the time of calibration stored in the memory 73, the control unit 70 positions the lens holding unit 353 from the origin position to the true initial position. This completes the initialization. When the lens holding portion 353 is moved to the temporary position of the initial position, it may be disposed at the same position as the true initial position if there is no positional deviation.

A problem when the initialization is performed by the above-described method will be described with reference to FIG. FIG. 6 is a schematic configuration diagram showing a part of a conventional astigmatism correcting optical system. Conventionally, the initial position (for example, 0D position) and the origin position are arranged so as to substantially coincide. Therefore, there is a possibility that the initial position may be arranged on either the plus side or the minus side of the origin position due to the above-described assembly error. Here, shifting to the plus side means shifting in the direction in which the lens holding unit 353 rotates at the time of detecting the origin, and shifting to the minus side means in a direction opposite to the direction in which the lens holding unit 353 rotates at the time of detecting the origin. It is to shift. The direction in which the lens holding portion 353 rotates at the time of origin detection is set in advance as one direction as described above.
FIG. 6A is a schematic diagram illustrating a case of shifting to the minus side, and FIG. 6B is a schematic diagram illustrating a case of shifting to the plus side. Therefore, in the case of FIG. 6A, when the lens holding portion 353 is rotated in the direction of the arrow, it immediately reaches the origin position. However, in the case of FIG. 6B, when the lens holding portion 353 is rotated in the direction of the arrow, there is a problem that it is necessary to make one round until the origin position, which takes time.

  Here, an initialization method for solving the above problem will be described with reference to FIG. FIG. 7 is a schematic configuration diagram showing a part of the astigmatism correcting optical system of the present embodiment. FIG. 7A is a schematic view showing a part of the cylindrical lens 340a and the rotation mechanism 350a in the initial position. The initial position and the origin position do not coincide with each other, and the origin position is tilted by an angle θ larger than the error range of the predicted initial position. This error is due to the assembly error of the apparatus and the machining tolerance of the parts. The angle θ can be arbitrarily set. In the present embodiment, the angle θ is set to 5 °. The rotation mechanism 350a is rotated in a fixed direction by the motor 351 from the initial position to the origin position at the time of initialization. At that time, the rotation direction of the motor 351 is a direction approaching the origin position from the initial position, and this rotation direction (detection operation direction) is preset and stored in the memory 73 (FIG. 2). The angle θ is preferably as small as possible in consideration of a predicted error. This is to shorten the time during which the rotation mechanism rotates during the initialization operation.

  The control unit 70 initializes the astigmatism correction optical system 340 as appropriate, such as when the apparatus is started up or when printing and data clear. The initialization operation of the astigmatism correction optical system 340 will be described by taking the cylindrical lens 340a and the rotation mechanism 350a as an example.

  At the time of subjective distance vision measurement, the control unit 70 drives the astigmatism correction optical system based on the astigmatism power C and the astigmatism axis angle A of the subject eye obtained by the distance objective refractive power measurement. Correct astigmatism. At this time, the control unit 70 positions the cylindrical lens 340a based on the rotation amount (or the number of steps of the motor) and the direction from the position where the astigmatism power becomes 0D, and the rotation amount and the rotation direction at that time are stored in the memory 73. Is remembered.

  When the subjective visual acuity test is completed, the control unit 70 sends a signal to the motor 351. This signal includes information on the rotation amount and rotation direction of the motor 351 stored in the memory 73 at the time of measurement. As the motor 351 rotates, the lens holding unit 353 returns to the initial position.

  Next, the control unit 70 rotates the motor 351 in the detection operation direction. At the same time, sensor light is emitted from the transmitter 61a. As the motor 351 rotates, the gear 352 rotates. The tooth portion 354 that meshes with the gear 352 rotates in conjunction with it, and the lens holding portion 353 and the cylindrical lens 340a rotate accordingly.

  When the two light passage holes 355 are located on the optical axis L3 of the sensor light traveling from the transmission unit 61a toward the reception unit 62a, the reception unit 62a detects the sensor light. At this time, the receiving unit 62 a sends a detection signal to the control unit 70. When receiving the detection signal, the control unit 70 stops driving the motor 351, and stops the lens holding unit 355 in a state where the receiving unit 62a detects the sensor light.

  FIG. 7B is a schematic view showing a part of the cylindrical lens 340a and the rotating mechanism 350a that have returned to the position where the astigmatism power becomes 0D after the subjective visual acuity test. As shown in FIG. 7, the initial position (for example, 0D position) may be shifted to the plus side or the minus side with respect to the position when there is no assembly error. Here, the magnitude of the expected deviation is assumed to be the angle α.

  When the initial position is shifted to the minus side by the angle α, the rotation mechanism 350a immediately reaches the origin position when rotating in the direction of the arrow. When the initial position is shifted to the plus side by the angle α, the rotation mechanism 350a immediately reaches the origin position, unlike the conventional case, when rotating in the direction of the arrow.

  In this way, when the initial position is shifted in the direction set in advance to detect the origin position by arranging the position where 0D is not coincident with the origin position and being inclined at an angle θ larger than the predicted deviation. However, the origin detection operation need only be a slight rotation operation, and it is possible to prevent the initialization time from becoming long.

  Next, the control unit 70 sends a signal for rotating the lens holding unit 353 to the initial position to the motor 351. This signal includes position information (for example, a rotation amount and a rotation direction from the origin position) of the initial position stored in advance in the memory 73. The motor 351 is rotated based on a signal from the control unit 70 and rotates the lens holding unit 353 to the initial position. The rotation direction at this time is a close direction from the origin position to the initial position.

  The configuration and initialization operation of the astigmatism correction optical system 340 have been described by taking the cylindrical lens 340a and the rotation mechanism 350a as an example, but the same applies to the cylindrical lens 340b and the rotation mechanism 350b.

  In addition, although demonstrated as a structure using an optical sensor as an origin return detection sensor, it is not limited to this. Any sensor that can detect the rotational position of the object, such as a magnetic sensor, may be used.

  The control unit 70 is connected to the image sensor 22 and performs a refractive power calculation process based on the output of the image sensor 22. In addition, the control unit 70 includes an image sensor 52, a moving mechanism 23, a driving mechanism 38, a motor 37, a light source 31, rotating mechanisms 350a and 350b, a display monitor 7, a switch unit 80 used for various settings, a measurement start switch 5b, and a memory. 73, an image memory 75, a drive unit 6, a printer 90, and the like.

  FIG. 3 is an explanatory diagram of the switch configuration of the switch unit 80 and the display on the monitor 7. The screen of the monitor 7 in FIG. 3 is an example of the subjective visual acuity measurement screen 200. In the switch unit 80, eight switches 80a to 80h are arranged. The function of each switch signal is switched in accordance with the screen of the monitor 7 that is switched by selecting the measurement mode.

  Next, the measurement operation of the apparatus having the above configuration will be described. When the device is activated, it is set to the objective power measurement mode for distance use. In this case, as the visual target 32a of the visual target presenting optical system 30, a fixation target (for example, a landscape visual target) for applying cloud fog is set in the optical path. The examiner fixes the subject's face to the face support unit 2, and a fixation target arranged in the measurement unit 4 via the measurement window 4 a (see FIG. 1) of the measurement unit 4 is applied to the subject's eyes. Let me fix it.

  When measuring objective refractive power, the anterior segment of the subject's eye E is imaged by the imaging element 52 of the observation optical system 50, and an anterior segment image is displayed on the monitor 7. In addition, the ring index image projected by the ring projection optical system 41 and the index image at infinity projected by the index projection optical system 42 are captured by the image sensor 52. These alignment index images are also displayed on the monitor 7. The examiner observes the anterior segment image, alignment target image, and reticle on the monitor 7, moves the measurement unit 4 and the moving table 3 by operating the joystick 5, etc. Are aligned in a predetermined positional relationship. When the measurement start signal is input from the measurement start switch 5b after the alignment is completed, the refractive power is measured.

  When the automatic alignment mode is set by a switch (not shown), the control unit 70 detects the alignment state based on the alignment index image captured by the image sensor 52. The alignment state in the vertical and horizontal directions is detected by the positional relationship between the center position of the ring index image by the ring projection optical system 41 and the optical axis. The alignment state in the working distance direction is detected by utilizing the characteristic that the infinity index by the index projection optical system 42 does not change even if the working distance changes, and the image interval in the predetermined meridian direction of the ring index changes. (See JP-A-6-46999). Based on the detection results of these alignment index images, the drive unit 6 is driven, and the measurement unit 4 is moved so that the alignment state is appropriate. When the alignment is completed, a trigger for a measurement start signal is automatically issued by the control unit 70, and the distance power measurement is performed.

  The measurement light emitted from the light source 11 is projected onto the fundus oculi Ef via the relay lens 12 to the dichroic mirror 29, and forms a spot-like point light source image on the fundus oculi Ef. The light of the point light source image formed on the fundus oculi Ef is reflected and scattered by the fundus occupying the subject eye E, and the optical system up to the objective lens 14, the hall mirror 13, the relay lens 16 and the total reflection mirror 17. Then, the light is condensed again on the aperture of the light receiving diaphragm 18 and is made into a substantially parallel light beam (in the case of a normal eye) by the collimator lens 19. It is taken out as a ring-shaped light beam by the ring lens 20 and received by the image sensor 22 as a ring image.

  In the measurement of the distance objective eye refractive power, first, preliminary measurement of eye refractive power is performed, and the light source 31 and the fixation target plate 32 are moved in the direction of the optical axis L2 based on the result of the preliminary measurement. The cloud E is applied to the eye E. Thereafter, the main measurement of the eye refractive power is performed on the eye to be inspected with fog. In this measurement, a ring image by the ring lens 20 is picked up by the image pickup device 22, and an output signal from the image pickup device 22 is stored in the image memory 75 as image data (measurement image). Thereafter, the control unit 70 performs image analysis on the ring image stored in the image memory 75 to obtain the value of refractive power in each meridian direction. The control unit 70 obtains objective values of S (spherical power), C (astigmatic power), and A (astigmatic axis angle) of the subject's eye during distance use by performing a predetermined process on the refractive power. . The objective value obtained at the time of distance use is stored in the memory 75.

  The eye refractive power measurement optical system 10 is not limited to the configuration using the ring-shaped index image as described above, and projects the measurement index on the fundus, receives the reflected light beam from the fundus with the light receiving element, and at least 3 Any optical system that obtains the refractive power in the meridian direction can be used, and a known one can be used.

  When the objective power measurement for distance use is completed and the switch 80a is pressed, the monitor 7 switches to the subjective distance vision measurement (objective power measurement) mode, and the screen of the monitor 7 is the screen of the objective power measurement mode. (Not shown) is switched to the subjective distance vision measurement screen 200 shown in FIG. The control unit 70 drives the correction optical system based on the refractive power (spherical power S, astigmatism power C, astigmatism shaft angle A) of the subject's eye obtained by measuring the objective refractive power for distance use. Correct the refractive error of the human eye. That is, the light source 31 and the target plate 32 are moved in the direction of the optical axis L2 based on the spherical power S in the distance objective refractive power measurement, so that the refractive power error of the spherical refractive power S is corrected. . Further, the astigmatism correction optical system 340 is driven based on the astigmatism power C and the astigmatism axis angle A, so that the correction state in which the refractive power error of astigmatism is corrected is obtained. Further, the control unit 70 rotates the target plate 32 by controlling the rotation of the motor 37, and arranges a predetermined visual acuity value visual target 32a on the optical axis L2 (for example, a visual target having a visual acuity value 0.8).

  As described above, when the initial presentation target is presented to the subject's eye, the examiner measures the distance vision of the subject. When the switches 80b and 80c corresponding to the UP and DOWN displays 202a and 202b of the visual acuity value are pressed, the visual acuity value target to be presented is switched. If the examinee's answer is correct, the examiner selects the switch 80b to switch to a visual target having a higher visual acuity value. On the other hand, if the subject's answer is an incorrect answer, the switch 80c is selected to switch to a target with a visual acuity value one step lower. The control unit 70 rotates the visual target plate 32 based on a signal input for changing the visual acuity value by the switch 80b or 80c, and switches the visual acuity value visual target 32a on the optical axis of the visual target presenting optical system. The examiner obtains the maximum visual acuity that can be read by the subject by repeating the above procedure.

  When the maximum vision value for distance using the correction power of the objective refractive power measurement result is obtained, the examiner adjusts the spherical power (the weakest power) from the most plus that allows the subject to obtain the highest vision value. The spherical power S is changed by operating the switches 80f and 80g corresponding to the UP / DOWN displays 204a and 204b for changing the spherical power in FIG. When the switch 80f or the switch 80e is selected, the light source 31 and the target plate 32 are moved in the direction of the optical axis L2, and the spherical power is changed. As a result, the weakest spherical power S at which the highest visual acuity is obtained is determined, and a reference value for prescribing the distance correction power such as a spectacle lens or a contact lens is obtained.

  Next, the examiner performs near vision measurement by moving the presented visual target to the near distance. When the switch 80h for inputting a signal for shifting to the near vision measurement mode is pressed, a near vision measurement screen is displayed on the monitor 7. FIG. 4 is a display example of the near vision measurement screen 220. In the near vision measurement screen 220, the “ADD” display 221 corresponds to the switch 80d, and a command signal for adding power is added by the switch 80d when the near vision is measured. The visual acuity value UP / DOWN displays 202a and 202b correspond to the switch 80b and the switch 80c. In addition, UP / DOWN displays 224a and 224b for changing the power of addition correspond to the switches 80f and 80g, respectively. The display field 230 on the screen 220 displays the near distance in the near vision measurement. The addition level is displayed in the display field 231 in the center of the monitor 7. In the measurement result display column 240, the correction power values (S, C, A) for distance use are displayed. In the display field 241 next to the display field 240, the value of the objective refractive power measurement result (S, C, A) for near use is displayed.

  When switched to the near vision measurement mode by the switch 80h, the light source 31 and the target plate 32 are moved on the optical axis L2 by driving the drive mechanism 38, and the target presentation distance by the target plate 32 is predetermined. Moved to the near distance. For example, the visual target is set at a position corresponding to a near distance of 33 cm. A near distance of 33 cm corresponds to −3.0 D (diopter) in terms of refractive power. The control unit 70 is as close as 3.0D (diopter) based on the position of the correction power for distance (the correction power for distance determined by the objective refractive power measurement for distance or the visual acuity measurement for distance). The target plate 32 is moved to a position closer to the direction. That is, it is set to a power obtained by adding a spherical power of −3.0D (diopter) to the correction power for distance use. For example, when the distance spherical power of the subject's eye is -2.0D, -3.0D is added to this, and the power at the near distance of 33 cm is -5.0D. It should be noted that when the switch 80h for shifting to the near vision measurement mode is pressed, there is no addition (0.00D). In the near measurement, the astigmatism refraction error is corrected by driving the astigmatism correction optical system based on the result of the distance objective refractive power measurement. Thus, the subject's eye can check the visual target presented at the near distance without being affected by the astigmatic refraction error.

  The examiner confirms the alignment state based on the anterior segment image and the alignment index image of the subject's eye displayed on the monitor 7, and makes the alignment appropriate. When the automatic alignment mode is set, the measurement unit 4 is automatically moved based on the detection result of the alignment index image, and the alignment is made appropriate. Thereafter, the examiner asks the subject whether or not the visual acuity target presented at the near distance 33 cm can be read. The subject's eye uses the eye's accommodation power to confirm the visual target presented at a near distance of 33 cm. At this time, if the alignment state is appropriate, the control unit 70 automatically generates a trigger signal for starting measurement, and performs objective refractive power measurement in near-field measurement. The objective refractive power measurement is performed a plurality of times (for example, three times) to obtain a representative value (for example, an intermediate value) of the measurement result excluding the abnormal data. In the case of manual measurement, the eye refractive power measurement for near use is performed by pressing the measurement start switch 5b.

  The measurement result (S, C, A) of the near-purpose objective eye refractive power is displayed in the display column 241. The control unit 70 compares the spherical power S1 required for the subject's eye to see the near visual target at the set near distance and the spherical power S2 obtained by the near-sighted objective eye refractive power measurement. Then, the difference (S2-S1) is obtained. The spherical power S1 is calculated based on the corrected spherical power for distance use and the power-converted power at the presentation distance of the near vision target. For example, since the corrected spherical power S for distance use is -2.00 D and the presentation distance 33 cm of the near vision target is -3.00 D, the eye of the subject is near vision at the set near distance. The spherical power S1 necessary for viewing the mark is calculated as -5.00D which is the sum of both. When the spherical power S2 obtained by measuring the near-field objective eye refractive power is -5.00D, the difference between S1 and S2 is 0, so that the subject's eye uses the adjustment power. Thus, it is determined that the near vision target is confirmed. In this case, since the addition is not required, the value in the addition display column 231 is set to 0.00D.

  On the other hand, when the spherical power S2 obtained by the near objective optic power measurement is −3.00D, the difference between the two (S2−S1) is + 2.00D. Is judged to have insufficient refractive power for viewing the near vision target. The difference of +2.00 D is displayed in the display field 231 as the addition power.

  The examiner can know whether the addition is necessary for the eye of the subject by checking the addition value displayed in the display field 231. That is, the control unit 70 determines the necessity of the addition in the near vision measurement, and notifies the examiner of the determination result by displaying the addition in the display field 231. As a result, the examiner can determine whether or not to perform the addition measurement step next. In addition, the examiner asks the subject whether or not the visual acuity target can be read. Even if the subject's response is ambiguous because the addition level is displayed in the display field 231. The subject can be urged to make it difficult to interpret the near vision target. When the difference between S1 and S2 (S2−S1) is about ± 0.50D, the eye adjustment lag (the focus position of the original eye is in focus in relation to the depth of focus). In consideration of the phenomenon of moving forward or backward within tolerance, the examiner may be informed that there is a possibility that the addition is not necessary. For example, when the addition level exceeds a certain value (0.50D), a message indicating that the addition level is required may be displayed on the screen.

  The examiner confirms the addition value in the display field 231 or a message indicating the necessity of the addition, and proceeds to the near vision measurement step in which the addition is added. When the switch 80d corresponding to the “ADD” display 221 is pressed, the control unit 70 drives the drive mechanism 38 to add the addition power to the correction optical system (target presentation optical system 30), and the near distance ( The target plate 32 is moved in the optical axis direction by an amount corresponding to the addition (difference between S1 and S2) calculated with the position of 33 cm) as a reference. As a result, in the addition measurement for near use, an appropriate initial value of the addition is easily set, and the measurement time for addition adjustment is shortened. That is, the initial value of the addition according to the individual of the subject compared to the case where the initial value of the addition is a constant value as in the conventional case or when the addition is set from the estimation of the age of the subject. Is set appropriately. Note that when the addition is added to the optotype presenting optical system 30, the value of the display 231 blinks.

  The examiner confirms the appearance of the presentation target in a state where the addition degree is added to the subject. When the subject answers that the target is easy to see, it is determined that the addition is appropriate. When the switches 80f and 80g are pressed, the addition applied to the correction optical system is increased or decreased in 0.25D steps. As a result, the examiner finely adjusts the addition according to the subject's eyes. The adjusted addition value is displayed in the display field 231. When the addition degree can be adjusted, the examiner switches the visual acuity values of the visual targets presented by the switches 80b and 80c, and measures the near visual acuity value at the limit of the subject's eyes.

  In addition, after the addition is adjusted, every time the switch 80d corresponding to the “ADD” display 221 is pressed, the state in which the addition is added to the target-presenting optical system and the state in which the addition is removed are alternately displayed. Is switched to. The state in which the addition power is removed is a state in which the astigmatism power is corrected and the spherical power is corrected based on the visual acuity confirmation measurement in the distance (or the measurement result of the eye refractive power in the distance). Thereby, the subject can compare the difference in the appearance of the near vision target depending on the presence or absence of the addition, and can know the necessity of the addition. For this reason, the examiner can easily explain the necessity of the addition at the near distance to the subject.

  The measurement results of the refractive power of the objective and the measurement results of the refractive power and addition of the subjective are used as reference values for precise subjective measurement. By obtaining the measurement results of these awareness by the objective refractive power measurement device, it becomes easy to determine the prescription value in the precise awareness measurement.

  In addition, if it is an apparatus which detects an origin position with a sensor and initializes, the same effect can be acquired using the structure and control system in the astigmatism correction optical system used in this embodiment.

  A rotating member including an optical member arranged in the optical path of the optotype presenting optical system 30, a rotation driving mechanism that has a drive source and rotates the rotating member with respect to the optotype presenting optical system 30, and in the vicinity of the rotating member The technology of the present embodiment is applied to any configuration provided with a sensor for detecting an origin return signal indicating that the rotation member has returned to the origin position for adjusting the rotation position of the rotation member. Is possible.

  For example, a target plate 32 in which a plurality of chart portions that are selectively arranged in the optical path of the target presentation optical system 30 are provided on the same circumference is used as the rotating member.

  FIG. 8A is an external configuration diagram of the optotype plate, and FIG. 8B is a schematic configuration diagram illustrating the optotype plate and the sensor. An optical sensor 63 is disposed around the target plate 32. The sensor 63 includes a transmission unit 64 and a reception unit 65, and detects the origin position of the target plate 32. The target plate 32 is provided with a light passage hole 321 through which sensor light can pass. The sensor 60 detects the rotational position of the target plate 32 only at the position (origin position) where the light passage hole 321 overlaps the optical axis L4 of the sensor light traveling from the transmission unit 64 toward the reception unit 65.

  Since the target presentation optical system 30 also needs to be initialized, the initialization time can be shortened by using the configuration and control system used in the astigmatism correction optical system of the present embodiment. .

  In addition, although demonstrated as a structure using the optical sensor as an initialization sensor, it is not limited to this. Any sensor that can detect the rotational position of the object, such as a magnetic sensor, may be used.

  In addition, the target plate 32 of the present embodiment is configured to be rotated by the motor 37, but is not limited thereto. For example, it may be configured to perform alignment by driving on a straight line.

  Subsequently, a second embodiment of the present invention will be described with reference to the drawings. FIG. 9 is a schematic configuration diagram showing a part of the astigmatism correcting optical system of the present embodiment. Since the astigmatism correction optical system of the present embodiment has a system that is substantially the same as that of the first embodiment shown in FIG. 5, the same reference numerals as those of the first embodiment are used for the respective elements.

  In general, in the second embodiment, a deviation due to an error when the lens holding portion 353 corresponding to the origin position is arranged so that the position of the lens holding portion 353 coincides with the initial position is determined, and the direction approaching the origin position from the initial position is determined as the origin position. A predetermined rotation direction for detecting the return signal is set. This is performed during calibration of the eye refractive power measurement apparatus.

  As shown in FIG. 9A, unlike the first embodiment, the astigmatism correcting optical system of this embodiment has an initial position and a signal detection position arranged in the vicinity.

  In the description, the cylindrical lens 340a and the rotation mechanism 350a are taken as an example. At the time of initialization, the control unit 70 rotates the rotation mechanism 350a in one preset direction when the origin position is detected by the sensor 60. This rotation direction is opposite to the rotation direction stored in the memory 73 at the time of calibration and going from the origin detection position to the position where it becomes 0D.

  FIG. 9B is a schematic configuration diagram showing a state when the initial position (for example, 0D position) is shifted from the origin position by an angle β in the cylindrical lens 340a and the rotation mechanism 350a. This deviation is due to the assembly error of the apparatus and the machining tolerance of the parts, and the correction value is stored in the memory 73 at the time of calibration.

  As described above, the direction in which the rotation mechanism 350a rotates during initialization is rotated in the opposite direction to the rotation direction from the origin position to the initial position, which is stored in the memory 73 as an adjustment value during calibration. By doing so, the initialization operation of the rotation mechanism 350a can be performed with a small amount of rotation, and the problem that the initialization time is prolonged as in the prior art can be solved.

It is an external appearance block diagram of an objective type eye refractive power measuring apparatus. It is a schematic block diagram of the optical system and control system of an apparatus. It is explanatory drawing of the switch structure of a switch part, and the display of a monitor. It is a display example of a near vision measurement screen. It is a perspective view which shows a part of astigmatism correction optical system. It is a schematic block diagram which shows a part of astigmatism correction optical system. It is a schematic block diagram which shows a part of astigmatism correction optical system. It is a schematic block diagram which shows a part of optotype presenting optical system. It is a schematic block diagram which shows a part of astigmatism correction optical system of 2nd Embodiment.

DESCRIPTION OF SYMBOLS 10 Eye refractive power measurement optical system 10a Projection optical system 10b Receiving optical system 30 Visual target presentation optical system (correction optical system)
70 Control unit 80 Switch unit 100 Objective eye refractive power measurement device 220 Near vision measurement screen 221 “ADD” display 231 display field

Claims (7)

A measurement optical system for projecting a measurement index on the fundus of the subject and receiving a reflected light beam from the fundus; and a target display optical system for presenting the target on the eye to be examined. In an eye refractive power measuring apparatus that objectively measures eye refractive power,
A rotating member including an optical member disposed in the optical path of the optotype presenting optical system;
A rotation drive mechanism having a drive source and rotating the rotating member;
A sensor provided in the vicinity of the rotating member for detecting an origin return signal indicating that the rotating member has returned to the origin position for adjusting the rotational position of the rotating member;
The driving source is controlled, the rotating member arranged at a predetermined initial position is rotated in a predetermined direction until an origin return signal is detected by the sensor, and the position of the rotating member is determined based on the detected origin position. Rotational position control means for adjusting
With
The ocular refractive power measuring apparatus, wherein the position of the rotating member corresponding to the origin position is set to a position outside the error range of the initial position. Having an operation unit operated by an examiner;
The said initialization control means starts the drive of the said drive source for detecting the said origin return signal after power activation or based on the predetermined operation signal from the said operation part. Eye refractive power measurement device.   2. The eye refractive power measurement apparatus according to claim 1, wherein a direction approaching the origin position from the initial position is set as a predetermined rotation direction for detecting the origin return signal and stored in a memory. Correction for correcting astigmatism of the subject's eye on which the target is presented, having two cylindrical lenses with equal focal lengths arranged so as to be rotatable about the optical axis in the optical path of the target presentation optical system With optical system,
The rotating member is a lens holding unit that holds the cylindrical lens,
2. The eye refractive power measuring apparatus according to claim 1, wherein the initial position is a position where an astigmatism power of the two cylindrical lenses is 0D.   2. The eye refractive power according to claim 1, wherein the rotating member is a target disc plate in which a plurality of chart portions that are selectively arranged in an optical path of the target presentation optical system are provided on the same circumference. measuring device. The rotational position control means
Moving the rotating member to a temporary position of the initial position;
The rotation member moved to the temporary position is rotated in a predetermined direction until the origin return signal is detected by the sensor, and the origin return signal is detected.
2. The eye refractive power measurement apparatus according to claim 1, wherein the rotating member is rotated by an adjustment amount stored in a memory with the detected origin position as a reference, and the rotating member is positioned at a true position of the initial position. A measurement optical system that projects a measurement index on the fundus of the subject and receives a reflected light beam from the fundus; and a target presentation optical system for presenting the target to the eye;
A rotating member including an optical member disposed in an optical path of the visual target presenting optical system, a rotation driving mechanism having a driving source and rotating the rotating member with respect to the visual target presenting optical system, and A sensor provided in the vicinity for detecting an origin return signal indicating that the rotating member has returned to the origin position for adjusting the rotational position of the rotating member;
The driving source is controlled, the rotating member arranged at a predetermined initial position is rotated in a predetermined direction until an origin return signal is detected by the sensor, and the position of the rotating member is determined based on the detected origin position. Rotational position control means for adjusting
A calibration method for an eye refractive power measurement device that objectively measures the eye refractive power of a subject's eye,
In order to check a deviation due to an error when the rotary member position corresponding to the origin position and the initial position coincide with each other, and to detect the origin return signal in the direction approaching the origin position from the initial position A method for calibrating an eye refractive power measuring device, characterized in that it is set as a predetermined rotation direction.

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