Ophthalmologic apparatus

Abstract

To provide an ophthalmologic apparatus capable of detecting a position of a measurement head with a space-saving and low-cost manner.SOLUTION: An ophthalmologic apparatus comprises: a head moving mechanism 13 that moves a measurement head 15 to a first position facing a first eye (a right eye ER) from an origin position and a second position facing a second eye (a left eye EL) from the origin position; an acceleration sensor 18 that moves integrally with the measurement head 15; a first calculation unit (head position calculation unit 38a) that calculates a first X position of the measurement head 15 based on an acceleration signal output from the acceleration sensor 18 while the measurement head 15 moves from the origin position to the first position; and a second calculation unit (head position calculation unit 38a) that calculates a second X position of the measurement head based on an acceleration signal output from the acceleration sensor 18 while the measurement head 15 moves from the origin position to the second position.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an ophthalmic apparatus including a head and a moving mechanism for moving the head. [Background technology]

[0002] An ophthalmic apparatus performs various measurements (including photography and observation) of a subject's eye, such as the ocular refractive power, intraocular pressure, corneal endothelial cell count, fundus images, tomographic images, and interpupillary distance. This ophthalmic apparatus includes a measurement head that performs various measurements of the subject's eye, and a head moving mechanism that moves the measurement head electrically or manually (see Patent Document 1). One type of such ophthalmic apparatus is known as a device that measures the interpupillary distance between the left and right subjects' eyes (left and right eyes).

[0003] In an ophthalmic apparatus for measuring interpupillary distance, for example, a head moving mechanism is manually driven to move the measurement head to a left eye-facing position facing the pupil of the left eye and a right eye-facing position facing the pupil of the right eye, and the X-direction positions of the measurement head at the left eye-facing position and the right eye-facing position are detected.The ophthalmic apparatus for measuring interpupillary distance then calculates the interpupillary distance based on the position detection results of the measurement head at the left eye-facing position and the right eye-facing position.

[0004] In such ophthalmic apparatuses for measuring the interpupillary distance, it is common to use various known encoders, such as optical linear encoders, to detect the position of the measuring head. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-006893 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when an encoder is used to detect the position of the measuring head, a large space for installing the encoder must be secured in the ophthalmic apparatus, and there is also the problem that the encoder is expensive.

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide an ophthalmic apparatus that is capable of detecting the position of a measuring head in a space-saving manner and at low cost. [Means for solving the problem]

[0008] An ophthalmologic apparatus for achieving the object of the present invention includes a measurement head that performs measurement of a subject's eye, a head moving mechanism that moves the measurement head from a predetermined origin position to a first position facing a first eye of one of the left and right eyes to be examined, and from the origin position to a second position facing a second eye of the other of the left and right eyes to be examined, an acceleration sensor that moves integrally with the measurement head, a first calculation unit that calculates a first X-position, which is the X-direction position of the measurement head that has moved to the first position, based on an acceleration signal output from the acceleration sensor while the head moving mechanism moves the measurement head from the origin position to the first position, when the left and right direction is defined as the X-direction, and a second calculation unit that calculates a second X-position, which is the X-direction position of the measurement head that has moved to the second position, based on an acceleration signal output from the acceleration sensor while the head moving mechanism moves the measurement head from the origin position to the second position.

[0009] According to this ophthalmologic apparatus, the first X position and the second X position of the measuring head can be obtained without using an encoder or the like.

[0010] In an ophthalmologic apparatus according to another aspect of the present invention, an origin position sensor is provided that detects that the measurement head has moved to an origin position, and a first calculation unit calculates a first X-position based on the detection result of the measurement head by the origin position sensor and an acceleration signal output from the acceleration sensor, and a second calculation unit calculates a second X-position based on the detection result of the measurement head by the origin position sensor and the acceleration signal output from the acceleration sensor. This makes it possible to determine the first X-position and the second X-position of the measurement head without using an encoder or the like.

[0011] In an ophthalmologic apparatus according to another aspect of the present invention, the origin position is the center position of the range in which the measurement head can be moved in the X direction by the head moving mechanism, and the origin position sensor is provided at the center position. This allows the first X position and the second X position of the measurement head to be obtained based on the detection result of the measurement head by the origin position sensor and the acceleration signal output from the acceleration sensor.

[0012] In an ophthalmologic apparatus according to another aspect of the present invention, the origin positions include a first origin position located at a position away from a center position in one direction in the X direction of a range in which the measurement head can be moved in the X direction by the head moving mechanism, and a second origin position located at a position away from the center position at the other direction in the X direction, and origin position sensors are provided at the first origin position and the second origin position. This allows the first X position and the second X position of the measurement head to be determined based on the detection result of the measurement head by the origin position sensor and the acceleration signal output from the acceleration sensor.

[0013] In an ophthalmologic apparatus according to another aspect of the present invention, the origin position is a limit position indicating the limit of the range in which the measurement head can be moved in the X direction by the head moving mechanism, and the origin position sensor is provided at the limit position. This makes it possible to determine the first X-position and the second X-position of the measurement head based on the detection result of the measurement head by the origin position sensor and the acceleration signal output from the acceleration sensor.

[0014] In an ophthalmologic apparatus according to another aspect of the present invention, when the up-down direction is defined as the Y direction and the direction perpendicular to both the X direction and the Y direction is defined as the Z direction, a first calculation unit calculates, based on the acceleration signal, a first X position, a first Y position which is the Y direction position of the measuring head moved to the first position, and a first Z position which is the Z direction position of the measuring head moved to the first position, and a second calculation unit calculates, based on the acceleration signal, a second X position, a second Y position which is the Y direction position of the measuring head moved to the second position, and a second Z position which is the Z direction position of the measuring head moved to the second position. This makes it possible to determine the first XYZ position and the second XYZ position of the measuring head without using an encoder or the like.

[0015] In an ophthalmologic apparatus according to another aspect of the present invention, the head moving mechanism includes a step motor as a drive source, a first movement amount calculation unit that calculates the movement amount of the measurement head based on the number of drive pulses of the step motor, a second movement amount calculation unit that calculates the movement amount of the measurement head based on an acceleration signal output from an acceleration sensor, and a step-out detection unit that detects step-out of the step motor based on the calculation results of the first movement amount calculation unit and the second movement amount calculation unit, thereby making it possible to detect step-out of the step motor.

[0016] In an ophthalmologic apparatus according to another aspect of the present invention, the first position and the second position are measurement positions where measurement of the eye to be examined can be performed by the measurement head, and when the measurement head is moved to the measurement position by the head moving mechanism, a head movement information calculation unit is provided which sets the measurement position as a new origin position and repeatedly calculates the movement direction and movement amount of the measurement head from the new origin position based on the acceleration signal output from the acceleration sensor, thereby making it possible to detect the position of the measurement head in real time.

[0017] In an ophthalmologic apparatus according to another aspect of the present invention, there is provided an operating member for operating the measurement head to move, and a manual movement control unit that drives the head moving mechanism in response to an operation of the operating member to move the measurement head, and when the measurement head is further moved after being moved to the measurement position by the head moving mechanism, the manual movement control unit reduces the movement speed of the measurement head in response to the operation below the movement speed before the measurement head was moved to the measurement position, thereby preventing the measurement head located near the face of the subject from approaching the face of the subject at high speed.

[0018] In another aspect of the present invention, the ophthalmologic apparatus further includes a display control unit that displays the movement direction and movement amount of the measurement head calculated by the head movement information calculation unit on the display unit, thereby allowing the examiner to grasp the position of the measurement head in real time.

[0019] In another aspect of the present invention, an ophthalmologic apparatus includes a pedestal, a head moving mechanism is provided between the measurement head and the pedestal, and has a moving member that moves integrally with the measurement head, and an acceleration sensor is provided on the moving member, thereby improving the detection accuracy of the position of the measurement head.

[0020] An ophthalmologic apparatus according to another aspect of the present invention includes an interpupillary distance calculation unit that calculates the interpupillary distance between the first eye and the second eye based on the calculation results of the first calculation unit and the calculation results of the second calculation unit. [Effects of the Invention]

[0021] The present invention can detect the position of the measuring head in a space-saving manner and at low cost. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram of an ophthalmologic apparatus according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a measuring head and a control device according to the first embodiment. [Figure 3] 5 is a flowchart showing the flow of a process for measuring the interpupillary distance between the left and right eyes to be examined by the ophthalmologic apparatus of the first embodiment. [Figure 4] FIG. 4 is a diagram showing the measuring head moved to the origin position in step S1 in FIG. 3. [Figure 5] 4 is a diagram showing the measurement head moved to a right-eye facing position facing the right eye of the subject's eye in step S2 in FIG. 3. FIG. [Figure 6] FIG. 4 is a diagram showing an example of an observation image displayed on the display unit when the measuring head is moved to a position facing the right eye in step S2 in FIG. 3. [Figure 7] FIG. 4 is a diagram showing the measurement head moved from the position facing the right eye to the origin position in step S4 in FIG. 3. [Figure 8] FIG. 4 is a diagram showing the measurement head moved to a position facing the left eye in step S5 in FIG. 3. [Figure 9]10 is an explanatory diagram for explaining a first origin position sensor and a second origin position sensor of an ophthalmologic apparatus according to a second embodiment. FIG. [Figure 10] FIG. 10 is a diagram showing the measuring head moved to a first origin position. [Figure 11] FIG. 10 is a diagram showing the measurement head moved from the first origin position to a position facing the right eye. [Figure 12] FIG. 10 is a diagram showing the measuring head moved to a second origin position. [Figure 13] FIG. 10 is a diagram showing the measurement head moved from the second origin position to a position facing the left eye. [Figure 14] 10 is an explanatory diagram for explaining a first origin position sensor 17R and a second origin position sensor 17L of an ophthalmologic apparatus according to a third embodiment. FIG. [Figure 15] FIG. 10 is a diagram showing the measuring head moved to a first origin position. [Figure 16] FIG. 10 is a diagram showing the measurement head moved from the first origin position to a position facing the right eye. [Figure 17] FIG. 10 is a diagram showing the measuring head moved to a second origin position. [Figure 18] FIG. 10 is a diagram showing the measurement head moved from the second origin position to a position facing the left eye. [Figure 19] FIG. 10 is a block diagram of an ophthalmologic apparatus according to a fourth embodiment. [Figure 20] FIG. 10 is a block diagram of an ophthalmologic apparatus according to a fifth embodiment. [Figure 21] 10A and 10B are diagrams showing examples of observed images before and after completion of auto-alignment. [Figure 22] 10 is a diagram showing an example of an observation image displayed on the display unit by the display control unit during execution of manual precision alignment of the measuring head. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] [First embodiment] 1 is a schematic diagram of an ophthalmologic apparatus 10 according to a first embodiment. Of the three mutually orthogonal X, Y, and Z directions in the figure, the Y direction is the up-down direction, the Z direction is the front-rear direction (also referred to as the working distance direction) in which the microscope approaches or moves away from the subject (the subject's eye E), and the X direction is the left-right direction perpendicular to both the up-down direction and the front-rear direction. In the Z direction (front-rear direction), the side approaching the subject's eye E (the subject) is referred to as the front side in the Z direction, and the side moving away from the subject's eye E (the subject) is referred to as the rear side in the Z direction.

[0024] As shown in Fig. 1, the ophthalmic apparatus 10 is an autorefractometer that measures the ocular refractive power as an ocular characteristic of the subject's eye E. The ophthalmic apparatus 10 also has a function of measuring the interpupillary distance PD (see Fig. 8, the same applies below) between the left and right subjects' eyes E in addition to the ocular refractive power of the subject's eye E. The ophthalmic apparatus 10 includes a stand 11, a face support unit 12, a head moving mechanism 13, an operating lever 14, a measurement head 15, and a display unit 16.

[0025] A face support unit 12 and a head moving mechanism 13 are provided on the base 11.

[0026] The face support section 12 is provided integrally with the pedestal 11. The face support section 12 has a chin rest section 12a and a forehead rest section 12b whose positions can be adjusted in the Y direction, and supports the face of the subject.

[0027] The head moving mechanism 13 is made up of an XZ moving section 13a and a Y moving section 13b, and holds the measuring head 15 so that it can move freely in the X, Y, and Z directions. The head moving mechanism 13 also has an origin position sensor 17 and an acceleration sensor 18.

[0028] The XZ moving unit 13a is provided on the platform 11. The XZ moving unit 13a is provided so as to be movable in the XZ directions (horizontal directions) by an electric actuator (not shown). A Y moving unit 13b and an operating lever 14 are provided on the XZ moving unit 13a.

[0029] Y moving unit 13b is provided so as to be movable in the Y direction on XZ moving unit 13a by an electric actuator (not shown). Measuring head 15 is provided on Y moving unit 13b. This allows measuring head 15 to be moved in the X, Y, and Z directions by moving XZ moving unit 13a in the XZ directions and moving Y moving unit 13b in the Y direction on XZ moving unit 13a.

[0030] The operating lever 14 is provided on the XZ moving section 13a at a position on the rear side (examiner side) of the measuring head 15 in the Z direction, and is an operating member that is operated when manually moving the measuring head 15 in each of the X, Y, and Z directions. Note that the measuring head 15 may be moved in the X, Y, and Z directions using an operating member other than the operating lever 14 for moving the measuring head 15.

[0031] For example, when the operation lever 14 is tilted in the Z direction or the X direction, the XZ moving unit 13a moves in the Z direction or the X direction in response to the tilting operation, and the measurement head 15 moves in the Z direction or the X direction together with the XZ moving unit 13a. When the operation lever 14 is rotated around its longitudinal axis, the Y moving unit 13b moves in the Y direction in response to the rotation, and the measurement head 15 moves in the Y direction together with the Y moving unit 13b. A measurement button is provided at the top of the operation lever 14 to start measurement of the ocular refractive power and interpupillary distance PD of the subject's eye E by the ophthalmologic apparatus 10.

[0032] The measurement head 15 has a function of measuring the ocular refractive power and interpupillary distance PD of the subject's eye E. A display unit 16 is provided on the rear surface of the measurement head 15 in the Z direction. The measurement head 15 also includes various optical systems (see FIG. 2) corresponding to the measurement of the ocular refractive power and interpupillary distance PD, and a control device 30.

[0033] The display unit 16 is, for example, a touch panel type liquid crystal display device. The display unit 16 displays various items, including an observation image 40 (see FIG. 6) of the anterior segment of the subject's eye E used for adjusting the position (alignment) of the measurement head 15, measurement results of the ocular refractive power and interpupillary distance PD of the subject's eye E obtained by the measurement head 15, and an input screen for performing various operations (settings).

[0034] The origin position sensor 17 is a sensor that indicates a predetermined origin position in the XYZ directions of the measuring head 15 that can be moved in the XYZ directions by the head moving mechanism 13, and is provided, for example, on each of the XZ moving unit 13a and the Y moving unit 13b.

[0035] The origin position sensor 17 provided on the XZ moving unit 13a is a center sensor located at the center of the range in which the measuring head 15 can be moved in the XZ directions by the XZ moving unit 13a. When the measuring head 15 has moved to the origin position in the X direction, the origin position sensor 17 outputs a detection signal indicating this to the control device 30, and when the measuring head 15 has moved to the origin position in the Z direction, the origin position sensor 17 outputs a detection signal indicating this to the control device 30.

[0036] Origin position sensor 17 provided on Y moving unit 13b is a center sensor located at the center of the range in which measuring head 15 can be moved in the Y direction by Y moving unit 13b. When measuring head 15 has moved to the origin position in the Y direction, origin position sensor 17 outputs a detection signal indicating this to control device 30.

[0037] The positions and number of the origin position sensors 17 are not limited to the example shown in FIG. 1, and can be changed as appropriate.

[0038] Acceleration sensor 18 is provided on Y moving part 13b (corresponding to the moving member of the present invention) which moves in the X, Y and Z directions together with measuring head 15. Acceleration sensor 18 is a known three-axis type sensor (or a type other than the three-axis type is also acceptable). Acceleration sensor 18 detects the acceleration of measuring head 15 (Y moving part 13b) in the X, Y and Z directions, and outputs the detected acceleration signals to control device 30.

[0039] Instead of providing one three-axis acceleration sensor 18 in the Y moving unit 13b, a two-axis acceleration sensor 18 that detects the acceleration in the X and Z directions of the measuring head 15 may be provided in the XZ moving unit 13a, and a one-axis acceleration sensor 18 that detects the acceleration in the Y direction of the measuring head 15 may be provided in the Y moving unit 13b. Alternatively, three one-axis acceleration sensors 18 that individually detect the acceleration in each of the X, Y, and Z directions of the measuring head 15 may be provided in the head moving mechanism 13 (XZ moving unit 13a, Y moving unit 13b).

[0040] The acceleration sensor 18 moves in each of the X, Y, and Z directions together with the measuring head 15. Therefore, by integrating twice the acceleration signals (acceleration values) in each of the X, Y, and Z directions output from the acceleration sensor 18, it is possible to calculate the movement vectors (movement direction and movement amount) of the measuring head 15 in each of the X, Y, and Z directions. This makes it possible to detect the position of the measuring head 15 in the X, Y, and Z directions without using an encoder as in the past. Therefore, in the ophthalmologic apparatus 10, the position of the measuring head 15 in the X, Y, and Z directions is detected using the acceleration sensor 18 instead of an encoder.

[0041] The acceleration sensor 18 may be provided in the measuring head 15 instead of in the head moving mechanism 13. However, if the acceleration sensor 18 is provided in the measuring head 15, the acceleration sensor 18 will also detect vibrations of the measuring head 15 that occur while the measuring head 15 is moving. As a result, there is a risk that the detection accuracy of the movement vectors in the X, Y, and Z directions (position in the X, Y, and Z directions) of the measuring head 15 will decrease. For this reason, it is preferable to provide the acceleration sensor 18 in the head moving mechanism 13, which is located below the measuring head 15.

[0042] 2 is a block diagram showing the configuration of the measurement head 15 and the control device 30 of the first embodiment. As shown in Fig. 2, the measurement head 15 is provided with an observation optical system 20, a Z alignment optical system 21, an XY alignment optical system 22, a fixation target projection optical system 23, a measurement pattern projection optical system 24, and a light receiving optical system 25.

[0043] The observation optical system 20 is an optical system used for observing the anterior segment of the subject's eye E, and captures an image of the anterior segment and outputs an observation image 40 (see FIG. 6) of the anterior segment to the control device 30.

[0044] The Z alignment optical system 21 is used to detect the alignment state of the measurement head 15 in the Z direction with respect to the eye E. The XY alignment optical system 22 is used to detect the alignment state of the measurement head 15 with respect to the eye E in the X and Y directions.

[0045] The fixation target projection optical system 23 fixes the line of sight of the subject's eye E by projecting a light beam of the fixation target onto the subject's eye E when measuring the ocular refractive power and interpupillary distance PD of the subject's eye E. The fixation target is also used for fixating and fogging the subject's eye E when measuring the ocular refractive power of the subject's eye E.

[0046] The measurement pattern projection optical system 24 projects a light beam of a ring-shaped measurement pattern (hereinafter simply referred to as the measurement pattern) used to measure the eye refractive power of the subject's eye E. The light receiving optical system 25 receives fundus reflected light of the measurement pattern light beam projected onto the subject's eye E by the measurement pattern projection optical system 24, and outputs a measurement pattern image based on the received light signal to the control device 30.

[0047] The detailed configuration of each optical system of the measurement head 15 is a known technique, and therefore a detailed description thereof will be omitted here.

[0048] The control device 30 controls the overall operation of each part of the ophthalmologic apparatus 10 and performs ocular refractive power measurement and interpupillary distance measurement of the subject's eye E. The control device 30 includes an arithmetic circuit configured with various processors, memories, etc. The various processors include a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), and a programmable logic device (e.g., simple programmable logic device (SPLD), complex programmable logic device (CPLD), and field programmable gate array (FPGA)). The various functions of the control device 30 may be realized by a single processor or by multiple processors of the same or different types.

[0049] The control device 30 is connected to each part of the head movement mechanism 13, the operating lever 14, each optical system of the measurement head 15, and the display unit 16. The control device 30 executes a control program read from a storage unit (not shown) to function as a head movement control unit 32, an alignment control unit 34, an eye refractive power measurement unit 36, and an interpupillary distance measurement unit 38. Hereinafter, what is described as a "unit" in this embodiment may also be a "circuit," a "device," or a "device." In other words, what is described as a "unit" may be composed of firmware, software, hardware, or a combination of these.

[0050] The head movement control unit 32 has a manual movement mode in which it drives the XZ movement unit 13a and the Y movement unit 13b to move the measuring head 15 in each of the X, Y, and Z directions in response to operations (tilting and rotating) of the operation lever 14. The head movement control unit 32 also has an automatic movement mode in which it drives the XZ movement unit 13a and the Y movement unit 13b to move the measuring head 15 in each of the X, Y, and Z directions under the control of an alignment control unit 34, which will be described later.

[0051] In this embodiment, the description will be given assuming that the head movement control unit 32 operates in the automatic movement mode when measuring the eye refractive power of the subject's eye E, and operates in the manual movement mode when measuring the interpupillary distance of the subject's eye E. Note that the head movement control unit 32 may operate in the manual movement mode when measuring the eye refractive power, and may operate in the automatic movement mode when measuring the interpupillary distance.

[0052] In this embodiment, the alignment control unit 34 operates when measuring the eye refractive power of the subject's eye E, and controls automatic alignment of the measuring head 15 with respect to the subject's eye E in the X, Y, and Z directions.

[0053] Specifically, the alignment control unit 34 controls the Z alignment optical system 21 and the XY alignment optical system 22 described above to perform XYZ alignment detection, which detects the relative position of the subject's eye E in the XYZ directions with respect to the measurement head 15. Note that XYZ alignment detection in the ophthalmic apparatus 10 (autorefractometer) is a well-known technique, so a detailed description thereof will be omitted here. Next, the alignment control unit 34 controls the head movement control unit 32 to drive the XZ movement unit 13a and the Y movement unit 13b based on the XYZ alignment detection result, thereby performing auto-alignment of the measurement head 15 with respect to the subject's eye E in the XYZ directions.

[0054] After the auto-alignment is completed, the eye refractive power measuring unit 36 ​​controls the fixation target projecting optical system 23, the measurement pattern projecting optical system 24, and the light receiving optical system 25 to automatically perform a rough measurement (provisional measurement) and a final measurement of the eye refractive power of the subject's eye E, and calculate the eye refractive power of the subject's eye E. Note that the rough measurement and the final measurement are also well-known techniques, so a detailed description thereof will be omitted here.

[0055] The interpupillary distance measurement unit 38 controls measurement and calculation of the interpupillary distance PD between the left and right eyes E to be examined. Furthermore, while measuring the interpupillary distance PD, the interpupillary distance measurement unit 38 displays, on the display unit 16, moving images 40 (see FIG. 6 ) of the anterior segments of the eyes E to be examined, which are continuously photographed by the observation optical system 20. To measure the interpupillary distance PD, the examiner operates the operation lever 14 to move the measurement head 15 to opposing positions facing the pupils of the left and right eyes E to be examined, and the interpupillary distance measurement unit 38 detects the positions (at least the position in the X direction) of the measurement head 15 at each opposing position. The interpupillary distance measurement unit 38 then calculates the interpupillary distance PD based on the position detection results of the measurement head 15 at each opposing position.

[0056] The interpupillary distance measuring unit 38 functions as a head position calculating unit 38a and an interpupillary distance calculating unit 38b, which correspond to the first and second calculating units of the present invention.

[0057] The head position calculation unit 38a calculates the XYZ direction position (or just the X direction position) of the measurement head 15 based on the detection result of the origin position sensor 17 and the acceleration signal output from the acceleration sensor 18. Specifically, when the measurement head 15 is moved to opposing positions facing the pupils of the left and right test eyes E, the head position calculation unit 38a calculates the XYZ direction position (or just the X direction position) of the measurement head 15 at each opposing position.

[0058] The interpupillary distance calculation unit 38b calculates the interpupillary distance PD between the left and right eyes E to be examined based on the calculation result of the head position calculation unit 38a.

[0059] Fig. 3 is a flowchart showing the flow of processing for measuring the interpupillary distance PD between the left and right eyes E to be examined by the ophthalmologic apparatus 10 of the first embodiment. Fig. 4 is a diagram showing the measurement head 15 moved to the origin position in step S1 in Fig. 3. Fig. 5 is a diagram showing the measurement head 15 moved to a right-eye facing position facing the right eye ER of the eye E to be examined in step S2 in Fig. 3. Fig. 6 is a diagram showing an example of an observation image 40 displayed on the display unit 16 when the measurement head 15 is moved to the right-eye facing position in step S2 in Fig. 3.

[0060] Note that the symbol XMR in Fig. 4 indicates the X movable range, which is the range in which the measuring head 15 can move in the X direction. Furthermore, the symbol XC in Figs. 4 and 5 indicates the X central position, which is the central position of the X movable range XMR. Furthermore, the symbol C in Fig. 5 indicates the main optical axis of the measuring head 15. In the following explanation, to avoid complicating the drawings, it is assumed that the measuring head 15 moved to the origin position in the Y and Z directions can also be detected by a single origin position sensor 17 arranged at the X central position XC.

[0061] 3 and 4, the examiner first operates the operation lever 14 to move the measurement head 15 in manual movement mode using the head movement control unit 32 to the origin position in the X, Y, and Z directions, i.e., to the position where the measurement head 15 is detected by the origin position sensor 17 (step S1 in FIG. 3). If it is not necessary to detect the Y and Z positions of the measurement head 15 at the position facing the right eye and the position facing the left eye, the measurement head 15 may be moved only to the origin position in the X direction (X central position XC). Next, the measurement head 15 is moved to the right-eye-facing position facing the pupil of the right eye ER of the subject's eye E. In this case, the right eye ER corresponds to the first eye in the present invention, and the position facing the right eye corresponds to the first position in the present invention.

[0062] 3, 5, and 6, the examiner operates the operation lever 14 to move the measurement head 15 to a position facing the right eye using the head movement control unit 32 in manual movement mode (step S2 in FIG. 3). For example, the examiner operates the operation lever 14 to manually adjust the position of the measurement head 15 so that the pupil image in the observation image 40 of the right eye ER displayed on the display unit 16 coincides with the index 42 indicating the main optical axis C of the measurement head 15 displayed on the display unit 16 (see FIG. 6). Next, the examiner presses, for example, the measurement button on the operation lever 14 to cause the head position calculation unit 38a to start calculating the position in the X, Y, and Z directions of the measurement head 15 that has been moved to the position facing the right eye.

[0063] The head position calculation unit 38a calculates the movement vector VR (movement direction and movement distance) of the measurement head 15 from the origin position by integrating twice the acceleration signal (acceleration value) in the XYZ directions output from the acceleration sensor 18 from the time the measurement head 15 is detected by the origin position sensor 17 until the measurement button of the operation lever 14 is pressed. Then, when the measurement button of the operation lever 14 is pressed, the head position calculation unit 38a calculates the movement vector VR of the measurement head 15 from the origin position to the position facing the right eye.

[0064] Next, the head position calculation unit 38a calculates the XYZ direction position of the measurement head 15 that has moved to the position facing the right eye, based on the known origin position and the calculation result of the movement vector VR (step S3 in FIG. 3). Note that the X direction position at this time corresponds to the first X position of the present invention, the Y direction position corresponds to the first Y position of the present invention, and the Z direction position corresponds to the first Z position of the present invention.

[0065] Next, the examiner moves the measurement head 15 to a position facing the left eye, facing the pupil of the left eye EL of the subject's eye E. In this case, the left eye EL corresponds to the second eye of the present invention, and the position facing the left eye corresponds to the second position of the present invention.

[0066] Fig. 7 is a diagram showing the measurement head 15 moved from the position facing the right eye to the origin position in step S4 in Fig. 3. Fig. 8 is a diagram showing the measurement head 15 moved to the position facing the left eye in step S5 in Fig. 3.

[0067] 3, 7, and 8, the examiner operates the operating lever 14 to move the measurement head 15 in manual movement mode using the head movement control unit 32 from the position facing the right eye, via the origin position (see FIG. 7), to the position facing the left eye (see FIG. 8) (steps S4 and S5 in FIG. 3). Then, the examiner operates the operating lever 14 so that the pupil image in the observation image 40 of the left eye EL displayed on the display unit 16 coincides with the index 42. Next, the examiner presses the measurement button on the operating lever 14 to cause the head position calculation unit 38a to start calculating the position in the X, Y, and Z directions of the measurement head 15 that has moved to the position facing the left eye.

[0068] If the measuring head 15 is detected again by the origin position sensor 17 while the measuring head 15 is moving to the position facing the left eye, the head position calculation unit 38a resets the calculation result of the movement vector VR to 0.

[0069] Then, the head position calculation unit 38a integrates the acceleration signals in the XYZ directions output from the acceleration sensor 18 twice from the time the measurement head 15 is redetected by the origin position sensor 17 until the measurement button on the operating lever 14 is pressed, and calculates the movement vector VL (movement direction and movement distance) of the measurement head 15 from the origin position.

[0070] When the measurement button of the operation lever 14 is pressed, the head position calculation unit 38a calculates a movement vector VL of the measurement head 15 from the origin position in the X, Y, and Z directions to the position facing the left eye. As a result, the head position calculation unit 38a calculates the X, Y, and Z direction positions of the measurement head 15 that has moved to the position facing the left eye, based on the known origin position and the calculation result of the movement vector VL, with the origin position as the reference (step S6 in FIG. 3). Note that the X direction position at this time corresponds to the second X position of the present invention, the Y direction position corresponds to the second Y position of the present invention, and the Z direction position corresponds to the second Z position of the present invention.

[0071] The interpupillary distance calculation unit 38b calculates the interpupillary distance PD between the right eye ER and the left eye EL based on the X-direction positions of the measurement head 15 at the right eye facing position and the left eye facing position calculated by the head position calculation unit 38a (step S7 in Figure 3).

[0072] As described above, in the ophthalmic apparatus 10 of the first embodiment, the position of the measuring head 15 can be detected using the origin position sensor 17 and the acceleration sensor 18, so there is no need to provide the ophthalmic apparatus 10 with an encoder for detecting the position of the measuring head 15 as in the past. Therefore, there is no need to secure a large space for installing the encoder in the ophthalmic apparatus 10. In addition, the origin position sensor 17 and the acceleration sensor 18 are cheaper than the encoder. As a result, the ophthalmic apparatus 10 of the first embodiment can detect the position of the measuring head 15 in a space-saving manner and at low cost.

[0073] [Second embodiment] Next, an ophthalmic apparatus 10 according to a second embodiment of the present invention will be described. In the ophthalmic apparatus 10 according to the first embodiment, a center sensor is used as the origin position sensor 17. However, in the ophthalmic apparatus 10 according to the second embodiment, instead of the origin position sensor 17, a first origin position sensor 17R corresponding to the right eye ER and a second origin position sensor 17L corresponding to the left eye EL are used.

[0074] The ophthalmic apparatus 10 of the second embodiment has basically the same configuration as the ophthalmic apparatus 10 of the first embodiment, except that it includes a first origin position sensor 17R and a second origin position sensor 17L instead of the origin position sensor 17. Therefore, components that are the same in function or configuration as those of the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0075] 9 is an explanatory diagram illustrating a first origin position sensor 17R and a second origin position sensor 17L of an ophthalmologic apparatus 10 according to a second embodiment. As shown in Fig. 9, the first origin position sensor 17R is provided at a first origin position that is a predetermined distance D away from the X central position XC of the X movable range XMR toward the right eye ER (one side in the X direction). The second origin position sensor 17L is provided at a second origin position that is a predetermined distance D away from the X central position XC of the X movable range XMR toward the left eye EL (the other side in the X direction).

[0076] The predetermined distance D is set to, for example, 32 mm, which is half the average interpupillary distance PD of 64 mm. Therefore, the first origin position sensor 17R is provided in a position near (peripheral position of) the right eye ER in the X direction. Also, the second origin position sensor 17L is provided in a position near the left eye EL in the X direction.

[0077] In order to avoid complicating the drawings, the first origin position sensor 17R and the second origin position sensor 17L will be described as functioning as center sensors in the YZ directions, similar to the origin position sensor 17 of the first embodiment.

[0078] Fig. 10 is a diagram showing the measurement head 15 moved to the first origin position. Fig. 11 is a diagram showing the measurement head 15 moved from the first origin position to a position facing the right eye. Fig. 12 is a diagram showing the measurement head 15 moved to the second origin position. Fig. 13 is a diagram showing the measurement head 15 moved from the second origin position to a position facing the left eye.

[0079] 10, in the second embodiment, the examiner first operates the operation lever 14 to move the measurement head 15 to the first origin position in manual movement mode using the head movement control unit 32. Next, as shown in Fig. 11, the examiner operates the operation lever 14 to move the measurement head 15 to a position facing the right eye in manual movement mode using the head movement control unit 32. Then, the examiner presses, for example, the measurement button on the operation lever 14 to cause the head position calculation unit 38a to start calculating the position in the X, Y, and Z directions of the measurement head 15 that has moved to the position facing the right eye.

[0080] The head position calculation unit 38a calculates a movement vector VR of the measurement head 15 from the first origin position by integrating twice the acceleration signal in the X, Y, and Z directions output from the acceleration sensor 18 from the time the measurement head 15 is detected by the first origin position sensor 17R until the measurement button of the operation lever 14 is pressed. Then, when the measurement button of the operation lever 14 is pressed, the head position calculation unit 38a calculates the movement vector VR of the measurement head 15 from the first origin position to the position facing the right eye. Next, based on the known first origin position and the calculation result of the movement vector VR, the head position calculation unit 38a calculates the X, Y, and Z direction positions of the measurement head 15 that has moved to the position facing the right eye, as in the first embodiment.

[0081] 12 and 13, after calculating the XYZ direction position of the measurement head 15 that has moved to the position facing the right eye, the examiner operates the operation lever 14 to move the measurement head 15 from the position facing the right eye to the position facing the left eye (see FIG. 13) via the first origin position and the second origin position (see FIG. 12) in manual movement mode using the head movement control unit 32. Then, the examiner presses the measurement button on the operation lever 14 to cause the head position calculation unit 38a to start calculating the XYZ direction position of the measurement head 15 that has moved to the position facing the left eye.

[0082] If the second origin position sensor 17L detects the measurement head 15 while the measurement head 15 is moving to the position facing the left eye, the head position calculation unit 38a resets the calculation result of the movement vector VR to zero.

[0083] Then, the head position calculation unit 38a integrates the acceleration signals in the XYZ directions output from the acceleration sensor 18 twice from the time the measurement head 15 is detected by the second origin position sensor 17L until the measurement button on the operating lever 14 is pressed, to calculate the movement vector VL of the measurement head 15 from the second origin position.

[0084] When the measurement button of the operation lever 14 is pressed, the head position calculation unit 38a calculates the movement vector VL of the measurement head 15 from the second origin position to the position facing the left eye. As a result, the head position calculation unit 38a calculates the XYZ direction position of the measurement head 15 that has moved to the position facing the left eye, similar to the first embodiment, based on the known second origin position and the calculation result of the movement vector VL.

[0085] As in the first embodiment, the interpupillary distance calculation unit 38b of the second embodiment calculates the interpupillary distance PD between the right eye ER and the left eye EL based on the X-direction positions of the measurement head 15 at the right eye facing position and the left eye facing position calculated by the head position calculation unit 38a.

[0086] As described above, in the ophthalmologic apparatus 10 of the second embodiment, the position of the measuring head 15 can be detected using the first origin position sensor 17R, the second origin position sensor 17L, and the acceleration sensor 18, and therefore, the same effects as in the first embodiment can be obtained.

[0087] Furthermore, in the second embodiment, the movement distance of the measurement head 15 from the first origin position to the position facing the right eye and the movement distance of the measurement head 15 from the second origin position to the position facing the right eye can be shortened. The longer this movement distance, the higher the possibility that noise such as vibrations generated during movement of the measurement head 15 will be detected by the acceleration sensor 18, which affects the position accuracy of the measurement head 15 calculated by the head position calculation unit 38a. Therefore, the second embodiment can improve the measurement accuracy of the interpupillary distance PD compared to the first embodiment.

[0088] In the second embodiment, the predetermined distance D is set to 32 mm, which is half the average interpupillary distance PD of 64 mm. However, the predetermined distance D can be set arbitrarily by providing the first origin position sensor 17R in a position near the right eye ER and the second origin position sensor 17L in a position near the left eye EL. For example, the predetermined distance D may be set to 20 mm or 50 mm. Furthermore, a plurality of first origin position sensors 17R may be provided at different positions, and a plurality of second origin position sensors 17L may be provided at different positions.

[0089] [Third embodiment] 14 is an explanatory diagram for explaining the first origin position sensor 17R and the second origin position sensor 17L of the ophthalmic apparatus 10 of the third embodiment. In the ophthalmic apparatus 10 of the second embodiment, the first origin position sensor 17R is provided in a position near the right eye ER, and the second origin position sensor 17L is provided in a position near the left eye EL. In contrast, as shown in FIG. 14, in the ophthalmic apparatus 10 of the third embodiment, the first origin position sensor 17R (first origin position) and the second origin position sensor 17L (second origin position) are provided at the limit position XE of the X-movable range XMR.

[0090] The ophthalmic apparatus 10 of the third embodiment has basically the same configuration as the ophthalmic apparatus 10 of the second embodiment, except that the first origin position sensor 17R and the second origin position sensor 17L are arranged differently. Therefore, components that are the same in function or configuration as those of the above embodiments are denoted by the same reference numerals, and descriptions thereof will be omitted.

[0091] The first origin position sensor 17R and the second origin position sensor 17L in the third embodiment are provided at the limit position XE, and are therefore limit sensors that detect when the measuring head 15 has moved to the limit position XE. Note that the first origin position sensor 17R and the second origin position sensor 17L will be described as functioning as center sensors in the Y and Z directions, similar to the second embodiment.

[0092] Fig. 15 is a diagram showing the measurement head 15 moved to the first origin position. Fig. 16 is a diagram showing the measurement head 15 moved from the first origin position to a position facing the right eye. Fig. 17 is a diagram showing the measurement head 15 moved to the second origin position. Fig. 18 is a diagram showing the measurement head 15 moved from the second origin position to a position facing the left eye.

[0093] As shown in FIG. 15, in the third embodiment, the examiner first operates the operating lever 14 to move the measuring head 15 to the first origin position (limit position XE) in manual movement mode using the head movement control unit 32.

[0094] 16, the examiner operates the operating lever 14 to move the measurement head 15 to the position facing the right eye using the head movement control unit 32 in manual movement mode. Then, the examiner presses the measurement button at the top of the operating lever 14, for example, to cause the head position calculation unit 38a to start calculating the X, Y, and Z directions of the measurement head 15 that has moved to the position facing the right eye. As a result, the head position calculation unit 38a calculates the movement vector VR as in the above embodiments, and also calculates the X, Y, and Z directions of the measurement head 15 that has moved to the position facing the right eye.

[0095] 17, the examiner operates the operation lever 14 to move the measuring head 15 from the position facing the right eye to the second origin position (limit position XE) in manual movement mode using the head movement control unit 32. As a result, the head position calculation unit 38a resets the calculation result of the movement vector VR to 0.

[0096] 18, the examiner operates the operating lever 14 to move the measurement head 15 from the second origin position to the position facing the left eye using the head movement control unit 32 in manual movement mode. Then, the examiner presses the measurement button on the operating lever 14 to cause the head position calculation unit 38a to start calculating the X, Y, and Z direction positions of the measurement head 15 that has moved to the position facing the left eye. As a result, the head position calculation unit 38a calculates the movement vector VL as in the above embodiments, and also calculates the X, Y, and Z direction positions of the measurement head 15 that has moved to the position facing the left eye.

[0097] As in the above embodiments, the interpupillary distance calculation unit 38b of the third embodiment calculates the interpupillary distance PD between the right eye ER and the left eye EL based on the X-direction positions of the measurement head 15 at the right eye facing position and the left eye facing position calculated by the head position calculation unit 38a.

[0098] As described above, in the ophthalmologic apparatus 10 of the third embodiment, the position of the measuring head 15 can be detected using the first origin position sensor 17R, the second origin position sensor 17L, and the acceleration sensor 18, and therefore, the same effects as in the first embodiment can be obtained.

[0099] In the third embodiment, the first origin position sensor 17R and the second origin position sensor 17L are provided at the limit positions XE on both sides of the X movable range XMR, but only one of the first origin position sensor 17R and the second origin position sensor 17L may be provided. For example, if only the first origin position sensor 17R is provided, after calculating the XYZ direction position of the measuring head 15 that has moved to the position facing the right eye, the examiner operates the operating lever 14 to directly move the measuring head 15 from the position facing the right eye (see FIG. 16) to the position facing the left eye (see FIG. 18).

[0100] [Fourth embodiment] Fig. 19 is a block diagram of an ophthalmic apparatus 10 according to a fourth embodiment. As shown in Fig. 19, the XZ movement unit 13a of the ophthalmic apparatus 10 according to the fourth embodiment includes two step motors 19 as drive sources, and the Y movement unit 13b includes one step motor 19 as a drive source. In this case, each step motor 19 rotates in synchronization with a drive pulse input from the head movement control unit 32 of the control device 30. However, if a sudden speed change or an overload occurs, step-out occurs, meaning that the step motors 19 cannot rotate in synchronization with the drive pulses.

[0101] Therefore, in the ophthalmic apparatus 10 of the fourth embodiment, the step-out of each step motor 19 is detected using an acceleration sensor 18 that moves integrally with the measuring head 15. The ophthalmic apparatus 10 of the fourth embodiment has basically the same configuration as the ophthalmic apparatus 10 of each of the above embodiments, except that the XZ movement unit 13a and the Y movement unit 13b are equipped with step motors 19 as drive sources, and the control device 30 functions as a first movement amount calculation unit 50, a second movement amount calculation unit 52, and a step-out detection unit 54. Therefore, components that are the same in function or configuration as those of the above embodiments are assigned the same reference numerals, and their description will be omitted.

[0102] When the measurement head 15 is moved by the head moving mechanism 13, the first movement amount calculation unit 50 calculates the movement amount of the measurement head 15 in each of the X, Y and Z directions using a known method based on the number of drive pulses (also called the number of drive steps) input to each step motor 19 from the head movement control unit 32.

[0103] When the measuring head 15 is moved by the head moving mechanism 13, the second movement amount calculation unit 52 calculates the movement amount of the measuring head 15 in each of the X, Y and Z directions based on the acceleration signal output from the acceleration sensor 18.

[0104] The out-of-step detection unit 54 detects out-of-step of each step motor 19 based on the movement amount of the measuring head 15 calculated by the first movement amount calculation unit 50 and the movement amount of the measuring head 15 calculated by the second movement amount calculation unit 52. For example, the out-of-step detection unit 54 determines that out-of-step of the step motor 19 has not occurred if the difference between the movement amount of the measuring head 15 calculated by the first movement amount calculation unit 50 and the movement amount of the measuring head 15 calculated by the second movement amount calculation unit 52 is within a predetermined threshold, and determines that out-of-step of the step motor 19 has occurred if this difference exceeds the threshold.

[0105] As described above, in the ophthalmic apparatus 10 of the fourth embodiment, it is possible to detect out-of-step of the step motor 19 by comparing the movement amount of the measurement head 15 calculated based on the number of drive pulses of the step motor 19 with the movement amount of the measurement head 15 calculated based on the acceleration signal output from the acceleration sensor 18.

[0106] [Fifth embodiment] 20 is a block diagram of an ophthalmic apparatus 10 according to a fifth embodiment. The ophthalmic apparatus 10 according to each of the above embodiments performs auto-alignment of the measuring head 15 with respect to the subject's eye E when measuring the eye refractive power of the subject's eye E, and automatically starts measuring the eye refractive power of the subject's eye E using the measuring head 15 after the auto-alignment is completed.

[0107] In contrast to this, in the ophthalmologic apparatus 10 of the fifth embodiment, the automatic start function of the ocular refractive power measurement of the subject's eye E by the measuring head 15 is turned off, and after the auto-alignment is completed, manual precision alignment of the measuring head 15 with respect to the subject's eye E can be performed. At this time, the ophthalmologic apparatus 10 of the fifth embodiment uses the acceleration sensor 18 to repeatedly detect the movement direction and movement amount of the measuring head 15 during the manual precision alignment and displays them on the display unit 16.

[0108] 20, the ophthalmologic apparatus 10 of the fifth embodiment has basically the same configuration as the ophthalmologic apparatus 10 of each of the above-described embodiments, except that the control device 30 functions as a head movement information calculation unit 56 and a display control unit 58. Therefore, components that are the same in function or configuration as those of each of the above-described embodiments are denoted by the same reference numerals, and their description will be omitted.

[0109] The head movement information calculation unit 56 operates when the automatic start function of measuring the ocular refractive power of the subject's eye E by the measuring head 15 is turned off. The head movement information calculation unit 56 first determines whether auto-alignment has been completed, that is, whether the measuring head 15 has been moved to a measurement position where measurement of the ocular refractive power of the subject's eye E can be performed.

[0110] Fig. 21 shows an example of an observation image 40 before and after completion of auto-alignment. As shown in Fig. 21, if the alignment of the measurement head 15 with respect to the subject's eye E in the X and Y directions is misaligned, a bright spot 44 indicating the pupil position of the subject's eye E in the observation image 40 is located outside a target frame 46 indicating the positional tolerance range of the bright spot 44 in the X and Y directions. Furthermore, if the alignment of the measurement head 15 with respect to the subject's eye E in the Z direction is misaligned, the bright spot 44 will be out of focus.

[0111] On the other hand, when auto-alignment is completed, that is, when the measuring head 15 is moved to the measurement position for the ocular refractive power of the subject's eye E, the bright spot 44 is positioned inside the target frame 46 and in focus in the observation image 40. Therefore, the head movement information calculation unit 56 can determine whether auto-alignment is completed, that is, whether the measuring head 15 has moved to the measurement position, based on the observation image 40 repeatedly captured by the observation optical system 20 during auto-alignment.

[0112] 20, when the head movement information calculation unit 56 determines that auto-alignment is complete and the measuring head 15 has been moved to the measurement position, it sets the position of the measuring head 15 after auto-alignment is complete as the new origin position (reset to 0).The head movement information calculation unit 56 then repeatedly calculates the movement direction and movement distance of the measuring head 15 in each of the X, Y, and Z directions based on the acceleration signals in the X, Y, and Z directions continuously output from the acceleration sensor 18.This makes it possible to detect the position of the measuring head 15 in real time while manual precision alignment of the measuring head 15 is being performed.

[0113] Note that the head movement control unit 32 (corresponding to the manual movement control unit of the present invention) of the fifth embodiment changes the movement speed of the measurement head 15 in response to the operation of the operating lever 14 when the measurement head 15 is further moved by manual precision alignment after the measurement head 15 has been moved to the measurement position by automatic alignment. Specifically, the head movement control unit 32 reduces the movement speed of the measurement head 15 in response to the operation of the operating lever 14 after the measurement head 15 has moved to the measurement position (during execution of manual precision alignment) compared to the movement speed before the measurement head 15 was moved to the measurement position. In other words, the head movement control unit 32 reduces the sensitivity of the operating lever 14 after the measurement head 15 has moved to the measurement position compared to before the movement. This prevents the measurement head 15 from approaching the subject's face at high speed during execution of manual precision alignment.

[0114] Fig. 22 is a diagram showing an example of an observation image 40 displayed on the display unit 16 by the display control unit 58 during execution of manual precision alignment of the measuring head 15. As shown in Fig. 22, the display control unit 58 causes the display unit 16 to display, as a moving image, the observation images 40 that are continuously captured by the observation optical system 20 during execution of manual precision alignment of the measuring head 15. The display control unit 58 also causes the display unit 16 to simultaneously display head movement information 48X, 48Y, and 48Z that indicate the results of calculation by the head movement information calculation unit 56 of the most recent movement direction and movement distance of the measuring head 15.

[0115] The head movement information 48X is a bar meter that indicates the direction and amount of movement of the measuring head 15 from the new origin position in the X direction. The head movement information 48Y is a bar meter that indicates the direction and amount of movement of the measuring head 15 from the new origin position in the Y direction. The head movement information 48Z is a bar meter that indicates the direction and amount of movement of the measuring head 15 from the new origin position in the Z direction. The examiner can determine the position of the measuring head 15 during manual precision alignment based on the head movement information 48X, 48Y, and 48Z displayed on the display unit 16. In particular, since it is difficult to determine the position of the measuring head 15 in the Z direction from the observation image 40 alone, by displaying the head movement information 48Z on the display unit 16, the examiner can easily determine the position of the measuring head 15 in the Z direction.

[0116] The display form of the head movement information 48X, 48Y, 48Z is not limited to a bar meter, and any display form may be used.

[0117] As described above, in the ophthalmic apparatus 10 of the fifth embodiment, the acceleration sensor 18 is used to repeatedly detect the direction and amount of movement of the measuring head 15 during manual precision alignment and display it on the display unit 16, thereby enabling the examiner to easily determine the position of the measuring head 15 during manual precision alignment.

[0118] [others] In the above embodiments, an autorefractometer (refractometer) that measures the ocular refractive power and interpupillary distance PD of the subject's eye E has been used as the ophthalmic apparatus 10, but the present invention is not limited to refractometers. The present invention is applicable to various ophthalmic apparatuses that include a measurement head 15 used for various measurements (including photography and observation) performed in ophthalmic examinations, such as the intraocular pressure value of the subject's eye E, the number of corneal endothelial cells, fundus images, and tomographic images, and a head moving mechanism 13 that moves the measurement head 15. [Explanation of symbols]

[0119] 10...Ophthalmological equipment 11... Mounting stand 12...Face support part 12a...Chin rest 12b...Forehead support 13...Head movement mechanism 13a...XZ moving part 13b...Y moving part 14...Operating lever 15...Measuring head 16…Display section 17...Origin position sensor 17L...Second origin position sensor 17R...First origin position sensor 18...Acceleration sensor 19...Step motor 20...Observation optical system 21...Z alignment optical system 22...XY alignment optical system 23…Fixation target projection optical system 24...Measurement pattern projection optical system 25…Receiving optical system 30...Control device 32...Head movement control unit 34...Alignment control unit 36...Eye refractive power measurement unit 38...Pupillary distance measuring section 38a...head position calculation unit 38b...Pupillary distance calculation section 40... Observation image 42…Indicators 44...Bright spot 46...Target frame 48X, 48Y, 48Z...Head movement information 50...First movement amount calculation section 52...Second movement amount calculation section 54...Step-out detection section 56...Head movement information calculation unit 58...Display control unit C…Main optical axis D...Predetermined distance E...Examined eye EL…Left eye ER…Right eye PD…Pupillary distance VL, VR...Movement vector XC…X center position XE…Limit position XMR…X movement range

Claims

1. a measurement head for performing measurements of the subject's eye; a head moving mechanism that moves the measurement head from a predetermined origin position to a first position facing a first eye of one of the left and right eyes to be examined, and from the origin position to a second position facing a second eye of the other of the left and right eyes to be examined; an acceleration sensor that moves integrally with the measuring head; a first calculation unit that calculates a first X position, which is an X-direction position of the measuring head that has moved to the first position, based on an acceleration signal output from the acceleration sensor during a time period until the head moving mechanism moves the measuring head from the origin position to the first position, when the left-right direction is defined as an X direction; a second calculation unit that calculates a second X position, which is an X-direction position of the measuring head that has moved to the second position, based on an acceleration signal output from the acceleration sensor while the head moving mechanism moves the measuring head from the origin position to the second position; An ophthalmic device comprising:

2. an origin position sensor that detects that the measuring head has moved to the origin position; the first calculation unit calculates the first X position based on a detection result of the measuring head by the origin position sensor and the acceleration signal output from the acceleration sensor; The ophthalmologic apparatus according to claim 1 , wherein the second calculation unit calculates the second X position based on a detection result of the measuring head by the origin position sensor and the acceleration signal output from the acceleration sensor.

3. the origin position is a central position of a range in which the measuring head can be moved in the X direction by the head moving mechanism, The ophthalmic apparatus according to claim 2 , wherein the origin position sensor is provided at the central position.

4. the origin position includes a first origin position located at a position away from a center position of a movable range of the measuring head in the X direction by the head moving mechanism on one side of the X direction, and a second origin position located at a position away from the center position on the other side of the X direction, The ophthalmologic apparatus according to claim 2 , wherein the origin position sensors are provided at the first origin position and the second origin position.

5. the origin position is a limit position indicating a limit of a movable range of the measuring head in the X direction by the head moving mechanism, 3. The ophthalmic apparatus according to claim 2, wherein the origin position sensor is provided at the limit position.

6. where the up-down direction is defined as a Y direction and the direction perpendicular to both the X direction and the Y direction is defined as a Z direction, the first calculation unit calculates, based on the acceleration signal, the first X position, a first Y position which is the Y direction position of the measuring head which has moved to the first position, and a first Z position which is the Z direction position of the measuring head which has moved to the first position; 2. The ophthalmologic apparatus according to claim 1, wherein the second calculation unit calculates, based on the acceleration signal, the second X position, a second Y position which is a Y direction position of the measuring head that has moved to the second position, and a second Z position which is a Z direction position of the measuring head that has moved to the second position.

7. the head moving mechanism includes a step motor as a drive source; a first movement amount calculation unit that calculates a movement amount of the measuring head based on the number of drive pulses of the step motor; a second movement amount calculation unit that calculates a movement amount of the measuring head based on the acceleration signal output from the acceleration sensor; a step-out detection unit that detects step-out of the step motor based on the calculation result of the first movement amount calculation unit and the calculation result of the second movement amount calculation unit; The ophthalmic device according to claim 1 .

8. the first position and the second position are measurement positions where the measurement head can measure the eye to be examined, 2. The ophthalmologic apparatus according to claim 1, further comprising a head movement information calculation unit that, when the measurement head is moved to the measurement position by the head movement mechanism, sets the measurement position as a new origin position and repeatedly calculates the movement direction and movement amount of the measurement head from the new origin position based on the acceleration signal output from the acceleration sensor.

9. an operating member for operating and moving the measuring head; a manual movement control unit that drives the head movement mechanism in response to an operation on the operation member to move the measuring head; The ophthalmologic apparatus according to claim 8, wherein when the measurement head is further moved after the measurement head has been moved to the measurement position by the head moving mechanism, the manual movement control unit reduces the movement speed of the measurement head in response to the operation below the movement speed before the measurement head was moved to the measurement position.

10. The ophthalmologic apparatus according to claim 8 , further comprising a display control unit that displays on a display unit the moving direction and amount of the measuring head calculated by the head movement information calculation unit.

11. Equipped with a stand, the head moving mechanism is provided between the measuring head and the base and has a moving member that moves integrally with the measuring head, The ophthalmologic apparatus according to claim 1 , wherein the acceleration sensor is provided on the moving member.

12. 11. The ophthalmologic apparatus according to claim 1, further comprising an interpupillary distance calculation unit that calculates an interpupillary distance between the first eye and the second eye based on a calculation result of the first calculation unit and a calculation result of the second calculation unit.

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