Optometer

Abstract

To properly determine the alignment state.SOLUTION: An optometer comprises: alignment detection means which detects the alignment state of inspection means to a subject eye; and control means which controls the operation of the optometer. The alignment detection means comprises: first index projection means which projects a first index for aligning the inspection means in a first direction being at least one direction of left-right, up-down and front-rear directions with respect to the subject eye onto the subject eye; a first detector which detects the first index projected onto the subject eye; second index projection means which projects a second index for aligning the inspection means in a second direction being at least one direction of the left-right, up-down and front-rear directions with respect to the subject eye and different from the first direction onto the subject eye; and a second detector which detects a second index projected onto the subject eye. The control means controls each exposure time of the first detector and the second detector in a shorter time than a frame interval such that timing of the exposure times does not overlap with each other.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to an optometry apparatus for examining an eye to be examined. [Background technology]

[0002] Inspection of the optical characteristics of the subject's eye, etc., is performed after aligning the inspection means with a predetermined positional relationship with the subject's eye. As a means for detecting the alignment state of the inspection means with respect to the subject's eye, for example, a device has been proposed that includes an alignment detection means that projects an index onto the subject's eye for detecting the alignment state in the left-right and up-down directions with respect to the subject's eye, and projects an index onto the subject's eye for detecting the alignment state in the front-back direction (working distance direction) with respect to the subject's eye, and detects each of the projected indices with separate detectors (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-38942 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the alignment detection means of Patent Document 1, for example, a detector for detecting the alignment state in the left-right and up-down directions may contain not only an index for detecting the alignment state in the left-right and up-down directions, but also an index for detecting the alignment state in the front-back direction, making it impossible to properly determine the alignment state.

[0005] In view of the above-mentioned conventional techniques, the present disclosure has an objective to provide an optometry apparatus capable of appropriately determining an alignment state. The present disclosure also has an objective to provide an optometry apparatus capable of determining the completion of alignment in a timely manner without delaying the determination of the timing of execution of the examination. [Means for solving the problem]

[0006] An optometry apparatus according to an aspect of the present disclosure is an optometry apparatus having an examination means for examining an eye to be examined, and includes an alignment detection means for detecting an alignment state of the examination means with respect to the eye to be examined, and a control means for controlling the operation of the optometry apparatus, wherein the alignment detection means includes a first index projection means for projecting a first index onto the eye to be examined for aligning the examination means in a first direction, which is at least one of left / right, up / down, and front / back with respect to the eye to be examined, a first detector for detecting the first index projected onto the eye to be examined, a second index projection means for projecting a second index for aligning the examination means in a second direction, which is at least one of left / right, up / down, and front / back with respect to the eye to be examined and is a direction different from the first direction, and a second detector for detecting the second index projected onto the eye to be examined, and the control means is characterized in that the exposure time of the first detector and the second detector is controlled to be shorter than a frame interval and such that the timing of the respective exposure times does not overlap. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a schematic external configuration of an optometry apparatus. [Diagram 2] FIG. 2 is a diagram showing an optical system arranged in a measurement unit. [Diagram 3] 1 is a schematic configuration diagram of the inside of an optometry apparatus as viewed from the front. [Figure 4] 2 is a schematic configuration diagram of the inside of the optometry apparatus as viewed from the side. FIG. [Diagram 5] 2 is a schematic configuration diagram of the inside of the optometry apparatus as viewed from above. FIG. [Figure 6] FIG. 2 is a diagram showing a control system of the optometric apparatus. [Figure 7] 10A to 10C are diagrams illustrating an example of control of the timing of exposure times of each image sensor and the timing of lighting of each light source. [Figure 8] 1A to 1C are diagrams illustrating examples of images captured by an imaging element that detects alignment indicators in the X and Y directions. [Figure 9]13 is a diagram showing an example of an image captured by an imaging element that detects an alignment index in the Z direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [overview] Hereinafter, one exemplary embodiment will be described with reference to the drawings. Note that the items grouped in <> below can be used independently or in conjunction with each other.

[0009] The optometry apparatus (e.g., the optometry apparatus 1) in this embodiment includes an examination means (e.g., a measurement unit 7), an alignment detection means (e.g., an alignment detection optical system 50A), and a control means (e.g., a control unit 70). For example, the examination means is used to examine the subject's eye. For example, the alignment detection means is used to detect the alignment state of the examination means with respect to the subject's eye. For example, the control means controls the operation of the optometry apparatus. For example, the optometry apparatus may include a light-guiding optical system (e.g., a light-guiding optical system 80).

[0010] <Testing method> For example, the inspection means includes an inspection optical system (for example, an objective measuring optical system 10). For example, the inspection optical system includes an inspection light source (for example, a light source 11) that projects inspection light onto the subject's eye, and an inspection light receiving element (for example, an image sensor 22) that receives return light of the inspection light from the subject's eye. For example, the inspection means may include an objective measuring optical system (for example, the objective measuring optical system 10) that measures the ocular refractive power of the subject's eye as the inspection optical system. The inspection means may also include a subjective measuring optical system (for example, the subjective measuring optical system 25). For example, the subjective measuring optical system may include a target projecting optical system (for example, a target projecting optical system 30) and a correction optical system (for example, a correction optical system 60).

[0011] <Alignment detection means> For example, the alignment detection means includes a first index projection means (e.g., a first index projection optical system 55), a first detector (e.g., an image sensor 52), a second index projection means (e.g., a second index projection optical system 40a), and a second detector (e.g., an image sensor 48).

[0012] For example, the first index projection means projects a first index (e.g., index 56I) onto the subject's eye for aligning the inspection means in a first direction, which is at least one of left-right (X direction), up-down (Y direction), and front-back (Z direction) with respect to the subject's eye. For example, the first direction is left-right (X direction) and up-down (Y direction) with respect to the subject's eye. For example, the first index projection means has a light source (e.g., light source 56) for projecting the index.

[0013] For example, the first detector detects a first index projected onto the subject's eye. For example, the first detector is provided in a first detection optical system (for example, the observation optical system 50) for detecting the first index projected onto the subject's eye. For example, the first detector uses at least one of an imaging element of a two-dimensional light receiving element which is an area sensor and a one-dimensional light receiving element which is a line sensor. For example, an alignment state of the inspection means in the first direction is detected based on an output signal from the first detector.

[0014] For example, the second index projection means projects a second index (e.g., index 41I) for aligning the inspection means in a second direction, which is at least one of left / right, up / down, and front / back with respect to the subject's eye and is a direction different from the first direction. For example, the second index is an index different from the first index. For example, the second direction is front / back with respect to the subject's eye (Z direction, working distance direction). For example, the second index projection means has a light source (e.g., light source 41) for projecting the index. For example, the wavelength of the light source of the second index may at least partially overlap with the wavelength of the light source of the first index.

[0015] For example, the second detector detects the second index projected onto the subject's eye. For example, the second detector is provided in a second detection optical system (for example, the second index projecting optical system 40a) for detecting the second index projected onto the subject's eye. For example, the second detector uses at least one of an imaging element of a two-dimensional light receiving element which is an area sensor and a one-dimensional light receiving element which is a line sensor. For example, the alignment state of the inspection means in the second direction is detected based on an output signal from the second detector.

[0016] <Control Means> For example, the control means controls the first detector and the second detector. For example, the control means controls the timing of the exposure time of the first detector (for example, exposure time Eta) and the exposure time of the second detector (for example, exposure time Etb) so that they do not overlap. For example, the control means controls the timing of the start and end of each exposure of the first detector and the second detector so that the exposure time of the first detector and the exposure time of the second detector do not overlap. This allows the alignment state to be appropriately determined.

[0017] For example, the control means controls the exposure time of each of the first detector and the second detector to a time shorter than the frame interval of a predetermined frame rate (for example, 30 fps (frames per second)). This allows the alignment state to be appropriately determined. For example, both the detection of the first index by the first detector and the detection of the second index by the second detector are performed at a predetermined frame rate (for example, 30 fps). Therefore, for example, even when the alignment state is detected in the left-right, up-down, and front-back directions using the first detector and the second detector, the detection results of the first index and the second index can be obtained within the same frame rate as in the case of alignment detection at the frame rate of one detector. This allows the completion of alignment to be determined in a timely manner, and inspection can be performed in a timely manner without causing a delay in the timing of inspection by the inspection means. This also allows highly reliable inspection results to be obtained without reducing the accuracy of the inspection results.

[0018] The exposure time is the time it takes for the detector to capture light, and the frame interval is the time for one frame at a given frame rate of the detector.

[0019] For example, the control means controls the exposure time of the first detector to be half the frame interval, and controls the exposure time of the second detector to be half the frame interval. The exposure times of the first and second detectors are not limited to this, and for example, it is sufficient that the total exposure time of the first detector and the second detector within a frame interval is within the frame interval. For example, the exposure time of the first detector may be 2 / 3 of the frame interval, and the exposure time of the second detector may be 1 / 3 of the frame interval.

[0020] Also, for example, the control means may adjust the relationship of the frame phase of each exposure time of the first detector and the second detector. For example, the control means may shift the relationship of the frame phase of the second detector to the frame phase of the first detector by the exposure time of the second detector. This allows the alignment state to be determined more appropriately. Also, by shifting the frame phase, the frame signals from the first detector and the second detector are not output simultaneously but are output in sequence, allowing efficient processing for image analysis of each frame signal.

[0021] For example, the control means controls the first index projection means and the second index projection means. For example, the control means controls the first index projection means and the second index projection means so that the second index is not projected onto the subject's eye within the exposure time of the first detector and the first index is not projected onto the subject's eye within the exposure time of the second detector. In this case, for example, the control means controls the lighting of the light source of the first index projection means and the light source of the second index projection means in accordance with the timing of each exposure time of the first detector and the second detector. Alternatively, mechanical or electronic shutters may be provided in the optical paths of the index projection of the first index projection means and the second index projection means, and the control means may control the opening and closing of the shutters provided in each optical path in accordance with each exposure time of the first detector and the second detector. This allows the alignment state in the left-right (X direction), up-down (Y direction), and front-back (Z direction) directions to be more appropriately determined.

[0022] <Inspection optics and wavelength limiting means for alignment detection> For example, the inspection optical system may include a first wavelength limiting means (e.g., a dichroic mirror 29), and the alignment detection means may include a second wavelength limiting means (e.g., a dichroic mirror 29, a lens 46). For example, the first wavelength limiting means is used to limit the wavelengths of the return light from the test eye of the first and second indices used for alignment from being incident on the inspection light receiving element of the inspection optical system. For example, the second wavelength limiting means is used to limit the wavelengths of the return light from the test eye of the inspection light from being incident on the first and second detectors. This allows the inspection means to properly inspect the optical characteristics of the test eye, etc., without being influenced by the first and second indices projected on the test eye, and allows the alignment state to be properly detected based on the first and second indices projected on the test eye, without being influenced by the inspection light.

[0023] For example, the first wavelength limiting means has a first optical member with wavelength selection characteristics (e.g., dichroic mirror 29) arranged in the optical path of the inspection optical system. For example, the first optical member with wavelength selection characteristics passes the wavelength of the inspection light but blocks the wavelengths of the first index and the second index, thereby limiting the incidence of the wavelengths of the first index and the second index into the optical path in which the inspection light receiving element is arranged.

[0024] For example, the second wavelength limiting means has a second optical member (e.g., dichroic mirror 29) with wavelength selection characteristics arranged in the optical path of the first detection optical system equipped with the first detector. For example, the second optical member passes the wavelength of the first index but blocks the wavelength of the inspection light, thereby limiting the incidence of the inspection light on the optical path on which the first detector is arranged. In addition, the second wavelength limiting means has a third optical member (e.g., lens 46) with wavelength selection characteristics arranged in the optical path of the second detection optical system equipped with the second detector. For example, the third optical member passes the wavelength of the second index but blocks the wavelength of the inspection light, thereby limiting the incidence of the inspection light on the optical path on which the second detector is arranged.

[0025] For example, in the case where the wavelength of the first index and the wavelength of the second index overlap at least partially, the light of the second index is incident on the first detector in addition to the light of the first index, and the light of the first index is incident on the second detector in addition to the light of the second index. Even in this case, the alignment state is appropriately determined by controlling the timing of the exposure times of the first detector and the second detector by the control means.

[0026] <Light guiding optical system> For example, the light-guiding optical system guides the index light of the first index and the second index to the eye to be examined, and guides the return light of the index light from the eye to the first detector and the second detector. The light-guiding optical system also guides the measurement light from the measurement optical system to the eye to be examined, and guides the return light of the measurement light from the eye to the measurement optical system. For example, the light-guiding optical system includes a light-guiding optical member (e.g., a concave mirror 85) for optically equivalently arranging the optical system of the inspection means at a predetermined working distance in front of the subject's eye when the alignment is completed. For example, this light-guiding optical system allows the eye examination device to perform alignment and measurement in an open state in front of the subject's eye without arranging the inspection means in front of the subject's eye. This allows the measurement of the subject's eye to be performed in a more natural state.

[0027] In the present disclosure, by adopting this light-guiding optical system, the index projection means used for aligning the inspection means with respect to the subject's eye can only project the index from an angle at which the index light beam can pass through the light-guiding optical member (e.g., the concave mirror 85) of the light-guiding optical system. In this case, in order to detect the alignment state of the inspection means with respect to the subject's eye in the front-rear direction with a practical resolution, a detector (e.g., the first detector) for detecting the alignment state in the left-right and up-down directions cannot be used. Therefore, a detector (e.g., the second detector) for detecting the alignment state in the front-rear direction is provided in addition to the detector for detecting the alignment state in the left-right and up-down directions. For example, the angle of the optical axis of the second index projection means and the optical axis of the index detection means having the second detector with respect to the optical axis of the inspection means located in the front direction of the subject's eye is set to an angle at which the index projection light and the return light from the subject's eye can pass through the light-guiding optical system.

[0028] [Example] An example of the optometry apparatus according to the present embodiment will be described. FIG. 1 is a diagram showing a schematic configuration of the exterior of the optometry apparatus 1. The optometry apparatus 1 may be any optometry apparatus equipped with an examination means for examining an eye to be examined, and may be, for example, a measurement apparatus for measuring the optical characteristics of the eye to be examined, a device for photographing the anterior part of the eye to be examined, a device for photographing the fundus of the eye to be examined, an OCT device for photographing a tomographic image of the fundus of the eye to be examined, or the like. In this embodiment, the optometry apparatus 1 will be described as an example of an apparatus equipped with an objective measurement unit for objectively measuring the optical characteristics (e.g., ocular refractive power) of the eye to be examined, and a subjective measurement unit for subjectively measuring the optical characteristics (e.g., ocular refractive power) of the eye to be examined. In the following description, the term "measurement" can be read as "examination".

[0029] In FIG. 1, the left-right direction (horizontal direction) as viewed from the subject side is the X direction, the up-down direction (vertical direction) is the Y direction, and the front-back direction (working distance direction) is the Z direction.

[0030] For example, the optometry apparatus 1 includes a housing 2, a presentation window 3, a forehead rest 4, a chin rest 5, a controller 6, a measuring unit 7 which is an example of an examination means, an imaging unit 90, an anterior eye illumination unit 92, and the like.

[0031] The presentation window 3 is used to present a visual target to the eye to be examined. The forehead rest 4, on which the subject's forehead rests, is used to keep a constant distance between the eye to be examined and the optometry device 1. The chin rest 5, on which the subject's chin rests, is used to keep a constant distance between the eye to be examined and the optometry device 1. The chin rest 5 is not necessarily provided.

[0032] The controller 6, which is an example of an operation unit, includes a display 6a, a switch unit 6b, and the like, which are examples of a display means. The display 6a displays various information (e.g., a measurement result of the subject's eye, etc.). The display 6a has a touch panel function and also functions as the switch unit 6b. The switch unit 6b may be used to perform various settings (e.g., input of operation signals for various places, etc.). A signal corresponding to an operation instruction from the controller 6 is output to a control unit 70 (see FIG. 6), which will be described later, by at least one of wired communication via a cable or the like and wireless communication via infrared or the like.

[0033] The imaging unit 90 includes an imaging optical system (not shown). For example, the imaging optical system is used to capture an image of the subject's face. For example, the imaging optical system may be composed of an imaging element and a lens. The anterior eye illumination unit 92 has an infrared illumination light source (not shown) disposed therein, and emits illumination light toward the left and right eyes to capture an image of the anterior eye of the subject's eye by the observation optical system 50 (see FIG. 2) described later.

[0034] <Measurement part> The measurement unit 7 includes a left eye measurement unit 7L and a right eye measurement unit 7R. In this embodiment, the left eye measurement unit 7L and the right eye measurement unit 7R are configured with the same member. Of course, the left eye measurement unit 7L and the right eye measurement unit 7R may be configured with at least a part of different members. The measurement unit 7 includes a pair of left and right target projection optical systems, which will be described later, a pair of left and right subjective measurement units, which will be described later, and a pair of left and right objective measurement units, which will be described later. The alignment light, the target light beam, and the measurement light beam from the measurement unit 7 are guided to the subject's eye through the presentation window 3.

[0035] FIG. 2 is a diagram showing optical systems arranged in the measurement unit 7. In FIG. 2, the measurement unit 7 is exemplified by the left eye measurement unit 7L. The right eye measurement unit 7R is omitted because it has the same configuration as the left eye measurement unit 7L. For example, the left eye measurement unit 7L includes a visual target projection optical system 30, a subjective measurement optical system 25, an objective measurement optical system 10, an observation optical system 50, an alignment detection optical system 50A, and the like. The subjective measurement optical system 25 and the objective measurement optical system 10 are examples of inspection optical systems.

[0036] <Target projection optical system> The visual target projecting optical system 30 projects a visual target light beam onto the subject's eye. For example, the visual target projecting optical system 30 includes a display 31, a projecting lens 33, a projecting lens 34, a reflecting mirror 36, an objective lens 37, a dichroic mirror 35, a dichroic mirror 29, and the like.

[0037] The display 31 displays a visual target (fixation target, test visual target, etc.). The visual target light beam emitted from the display 31 passes through the optical members from the light projecting lens 33 to the dichroic mirror 29 in order, and is projected onto the left eye E to be examined. The dichroic mirror 35 makes the optical path of the objective measurement optical system 10 and the optical path of the subjective measurement optical system 25 a common optical path. In other words, the dichroic mirror 35 makes the optical axis L1 of the objective measurement optical system 10 and the optical axis L2 of the subjective measurement optical system 25 coaxial. The dichroic mirror 29 is an optical path branching member. The dichroic mirror 29 reflects the visual target light beam from the visual target projection optical system 30 and the measurement light beam from the projection optical system 10a described later, and guides them to the eye E to be examined.

[0038] <Subjective Measuring Optical System> The subjective measurement optical system 25 is used as part of a subjective measurement unit that subjectively measures the optical characteristics of the subject's eye E. In this embodiment, a subjective measurement unit that measures the ocular refractive power of the subject's eye E is taken as an example of the optical characteristics of the subject's eye E. The optical characteristics of the subject's eye E may be contrast sensitivity, binocular vision function (e.g., amount of heterophoria, stereoscopic vision function, etc.), etc., in addition to ocular refractive power. For example, the subjective measurement optical system 25 is composed of the target projection optical system 30 and the correction optical system 60 described above.

[0039] <Correction optical system> The correction optical system 60 is disposed in the optical path of the visual target projection optical system 30. The correction optical system 60 also changes the optical characteristics of the visual target light beam from the display 31. As a result, for example, the correction optical system 60 changes the correction amount of the refractive power (spherical refractive power, astigmatic refractive power) imparted to the examinee's eye. For example, the correction optical system 60 includes an astigmatism correction optical system 63, a drive mechanism 39 used as a spherical correction optical system, and the like.

[0040] The astigmatism correcting optical system 63 is used to correct the astigmatism power (cylindrical power) and astigmatism axis angle of the subject's eye E. In this embodiment, the astigmatism correcting optical system 63 is disposed between the projector lens 33 and the projector lens 34. The astigmatism correcting optical system 63 is composed of two positive cylindrical lenses 61a and 61b having the same focal length. The cylindrical lenses 61a and 61b are each independently rotated about the optical axis L2 by the driving of the rotation mechanisms 62a and 62b.

[0041] In this embodiment, the cylindrical lens 61a and the cylindrical lens 61b are used as the astigmatism correcting optical system 63, but the present invention is not limited to this. The astigmatism correcting optical system 63 may be configured to correct the cylindrical power, the astigmatism axis angle, etc. As an example, a corrective lens may be inserted and removed from the optical path of the target projection optical system 30.

[0042] In this embodiment, the display 31 provided in the target projection optical system 30 is moved in the direction of the optical axis L2 of the target projection optical system 30 by a drive mechanism 39. For example, the drive mechanism 39 is composed of a motor and a slide mechanism. For example, during subjective measurement, the display 31 is moved to optically change the presentation position (presentation distance) of the target with respect to the subject's eye, and the spherical refractive power of the subject's eye is corrected. That is, in this embodiment, a correction optical system for spherical power is formed by moving the display 31. Then, the spherical power is measured based on the optical distance of the test target with respect to a reference position by moving the display 31.

[0043] The spherical correction optical system is not limited to this. For example, the spherical correction optical system may have a number of optical elements and may be configured to perform correction by arranging the optical elements in the optical path. Also, for example, the spherical correction optical system may be configured to move a lens arranged in the optical path in the optical axis direction.

[0044] <Objective measurement optical system> The objective measuring optical system 10, which is an example of an examination optical system, is used as a part of an objective measuring unit that objectively measures the optical characteristics of the subject's eye E. In this embodiment, an objective measuring unit that measures the ocular refractive power of the subject's eye E will be described as an example of the optical characteristics of the subject's eye E. For example, the objective measuring optical system 10 is composed of a projection optical system 10a and a light receiving optical system 10b.

[0045] The projection optical system 10a projects a spot-shaped measurement index onto the fundus of the subject's eye E through the center of the pupil of the subject's eye E. For example, the projection optical system 10a includes a light source 11, a relay lens 12, a hole mirror 13, a prism 15, an objective lens 14, a dichroic mirror 35, a dichroic mirror 29, and the like. For example, the dichroic mirror 35 transmits light wavelengths less than 750 nm and reflects light wavelengths equal to or greater than 750 nm. For example, the dichroic mirror 29 reflects light wavelengths less than 910 nm and transmits light wavelengths equal to or greater than 910 nm.

[0046] The light source 11 is, for example, an SLD (super luminescent diode) that emits a measurement light beam with a wavelength centered at 880 nm. The light source 11 is conjugate with the fundus of the subject's eye E. The hole of the hole mirror 13 is conjugate with the pupil of the subject's eye E. The prism 15 is a light beam deflecting member. The prism 15 is disposed at a position that is not conjugate with the pupil of the subject's eye E, and decenters the measurement light beam passing through the prism 15 with respect to the optical axis L1. The prism 15 is driven to rotate around the optical axis L1 by a drive unit (e.g., a motor) 23.

[0047] The light-receiving optical system 10b extracts the fundus reflected light beam reflected by the fundus of the test eye E in a ring shape through the pupil periphery of the test eye E. For example, the light-receiving optical system 10b includes a dichroic mirror 29, a dichroic mirror 35, an objective lens 14, a prism 15, a hole mirror 13, a relay lens 16, a mirror 17, a light-receiving diaphragm 18, a collimator lens 19, a ring lens 20, an image sensor 22 which is an example of a test light-receiving element, and the like.

[0048] The ring lens 20 is composed of a lens portion formed in a ring shape and a light-shielding portion in which a light-shielding coating is applied to the area other than the lens portion. The ring lens 20 is in an optically conjugate positional relationship with the pupil of the subject's eye E. The light-receiving diaphragm 18 and the image sensor 22 are in a conjugate relationship with the fundus of the subject's eye E. The output from the image sensor 22 is input to the control unit 70.

[0049] In the above configuration, the measurement light beam emitted from the light source 11 passes through the optical members from the relay lens 12, the hole mirror 13, and the prism 15 to the dichroic mirror 29 in order to form a spot-shaped point light source image on the fundus of the subject's eye E. At this time, the pupil projection image (projected light beam on the pupil) of the hole part of the hole mirror 13 is rotated eccentrically at high speed by the prism 15 rotating around the optical axis. The point light source image projected on the fundus is reflected and scattered and emitted as return light from the subject's eye E, reflected by the dichroic mirror 29 and the dichroic mirror 35, collected by the objective lens 102, and collected again on the light receiving diaphragm 18 via the prism 15, the hole mirror 13, the relay lens 16, and the mirror 17, which rotate at high speed. Thereafter, the return light from the subject's eye E is focused as a ring-shaped image on the image sensor 22 by the collimator lens 19 and the ring lens 20.

[0050] The dichroic mirror 29 has a wavelength selection characteristic of, for example, reflecting light with a wavelength of less than 910 nm and transmitting light with a wavelength of 910 nm or more. As a result, the dichroic mirror 29 transmits the alignment light (for example, a wavelength of 940 nm) of the alignment optical system 50A described later and reflects the measurement light with a wavelength of 880 nm. That is, the dichroic mirror 29 functions as a wavelength limiting member that limits the wavelength of the return light from the light source 56 and the light source 41 used for alignment from entering the image sensor 22. In addition, the anterior eye illumination unit 92 shown in FIG. 1 also emits near-infrared light with a wavelength of about 940 nm like the alignment light, so the dichroic mirror 29 also limits the incidence of this illumination light on the image sensor 22. In other words, the dichroic mirror 29 passes (here, reflects) the wavelengths of the measurement light, but blocks the wavelengths of the alignment light (indicators of light source 56 and light source 41), thereby limiting the incidence of the alignment light into the optical path in which the image sensor 22 is located.

[0051] In this embodiment, the prism 15 is disposed on a common optical axis of the projection optical system 10a and the light receiving optical system 10b. For example, the measurement light beam from the projection optical system 10a passes through the prism 15 and enters the subject's eye E, and the fundus reflected light beam reflected by the fundus of the subject's eye E passes through the same prism 15. Therefore, in the subsequent optical systems, the projection light beam and the fundus reflected light beam (received light beam) are scanned inversely as if there was no decentering of the projection light beam and the fundus reflected light beam (received light beam) on the pupil.

[0052] The eye refractive power measuring optical system, which is an example of the objective measuring optical system 10, is not limited to the above as long as it is configured to obtain eye refractive power. For example, it may be configured with a Shack-Hartmann sensor. For details of these, please refer to, for example, JP 2018-47049 A.

[0053] Furthermore, the light source 11 and relay lens 12 included in the projection optical system 10a, and the light receiving diaphragm 18, collimator lens 19, ring lens 20, and image sensor 22 included in the light receiving optical system 10b are movable together in the optical axis direction. In this embodiment, these are moved together in a synchronized manner as a drive unit 95 by a drive mechanism 39 that also moves the display 31. The movement position of the drive unit 95 moved by the drive mechanism 39 is detected by a detector (not shown). Of course, these may be configured to be driven individually.

[0054] By moving the drive unit 95 in the optical axis direction, the light source 11, the light receiving aperture 18, and the image sensor 22 are arranged so as to be optically conjugate with the fundus of the subject's eye E. Regardless of the movement of the drive unit 95, the hole mirror 13 and the ring lens 20 are arranged so as to be conjugate with the pupil of the subject's eye E at a constant magnification. For this reason, the fundus reflected light beam, which is the measurement light beam of the projection optical system 10a, is always incident on the ring lens 20 of the light receiving optical system 10b as a parallel light beam, and a ring-shaped light beam of the same size as the ring lens 20 is imaged by the image sensor 22 in a focused state, regardless of the ocular refractive power of the subject's eye E.

[0055] <Observation optical system> The observation optical system (imaging optical system) 50 includes a dichroic mirror 29, an objective lens 53, an imaging lens 51, an imaging element 52, etc. The dichroic mirror 29 transmits anterior-segment observation light and alignment light. The imaging element 52 has an imaging surface arranged at a position conjugate with the anterior segment of the subject's eye E. An area sensor is used for the imaging element 52. The output from the imaging element 52 is input to the control unit 70. As a result, an anterior-segment image of the subject's eye E is captured by the imaging element 52 and displayed on the display 6a.

[0056] Here, the dichroic mirror 29, due to the above-mentioned wavelength transmission characteristics, functions as a wavelength limiting member that limits the return light of the measurement light from the subject's eye from entering the image pickup element 52. In other words, the dichroic mirror 29 passes (here, transmits) the wavelength of the alignment light, but blocks the wavelength of the measurement light, thereby also serving as a member that limits the entrance of the measurement light into the optical path in which the image pickup element 52 is disposed.

[0057] <Alignment detection optical system> The alignment detection optical system 50A is used to detect the alignment state of the measurement unit 7 (measurement unit 7L for the left eye in FIG. 2) with respect to the subject's eye E (left eye EL in FIG. 2). The alignment detection optical system 50A includes a first target projection optical system 55, an observation optical system 50 also serving as the first detection optical system, a second target projection optical system 40a, and a second detection optical system 40b.

[0058] The first target projection optical system 55 projects a first target for aligning the measurement unit 7 in the XY directions with respect to the subject's eye E. The first target projection optical system 55 includes a light source 56 that emits near-infrared light (for example, wavelength 940 nm), a collimator lens 57, and a half mirror 58. The light emitted from the light source 56 is made into a substantially parallel beam by the collimator lens 57, and is reflected by the half mirror 58 to be coaxial with the optical axis L3 of the observation optical system 50. Thereafter, the light from the light source 56 passes through the dichroic mirror 29 and is projected onto the subject's eye E from the front direction of the subject's eye E.

[0059] The observation optical system 50 is also used as a first detection optical system that detects a first index projected onto the subject's eye E. That is, light from a light source 56 of the first index projection optical system 55 is reflected by the cornea of ​​the subject's eye E to form an index (corneal reflection bright spot) that is a virtual image of the light source 56, and the return light of the index from the subject's eye E passes through the dichroic mirror 29 and is received by the image sensor 52, which is an example of a detector, via the half mirror 58, the objective lens 53, and the imaging lens 51. Then, the position of the index is analyzed by the control unit 70 based on the output signal of the imaging sensor 52, and the alignment state of the subject's eye E in the XY directions is detected.

[0060] The second target projection optical system 40a includes a light source 41 that emits near-infrared light (for example, wavelength 940 nm) and a collimator lens 42, and projects a target from an oblique direction toward the cornea of ​​the subject's eye E. The wavelength of the near-infrared light emitted by the light source 41 at least partially overlaps with the wavelength of the light emitted by the light source 56 of the first target projection optical system 55.

[0061] The second detection optical system 40b detects the index projected onto the subject's eye E by the second index projection optical system 40a. The second detection optical system 40b includes a lens 46, a condenser lens 47, and an image sensor 48, which is an example of a detector. For example, an area sensor is used for the image sensor 48. Light from the light source 41 is reflected by the cornea of ​​the subject's eye E to form an index (corneal reflection bright spot), which is a virtual image of the light source 41. The light of the index is incident on the image sensor 48 via the lens 46 and the condenser lens 47. The position of the index on the image sensor 48 changes depending on the position of the subject's eye E in the Z direction. An output signal from the image sensor 48 is output to the control unit 70, and the alignment state of the subject's eye E in the Z direction is detected by the control unit 70.

[0062] Here, the lens 46 (or the condenser lens 47) has the same characteristic as the dichroic mirror 29, that is, it reflects light having a wavelength of less than 910 nm and transmits light having a wavelength of 910 nm or more. As a result, the return light of the index from the test eye by the light source 41 can pass through the lens 46 and enter the image sensor 48. On the other hand, the return light of the measurement light from the test eye by the light source 11 and visible light, which become noise light in the alignment detection, are restricted from entering the image sensor 48 by the wavelength selection characteristic of the lens 46. That is, the lens 46 having the wavelength selection characteristic functions as a wavelength limiting member that restricts the return light of the measurement light from the test eye from entering the image sensor 48. In other words, the lens 46 passes the wavelength of the alignment index of the light source 41, but blocks the wavelength of the measurement light, thereby restricting the entrance of the measurement light into the optical path in which the image sensor 48 is arranged.

[0063] The optical axis of the second detection optical system 40b is arranged symmetrically with the optical axis of the second index projection optical system 40a with respect to the optical axis L3 of the observation optical system 50 (which is also the optical axis L2 of the measurement optical system 10 coaxial with the optical axis L3). The angle α of the optical axes of the second index projection optical system 40a and the second detection optical system 40b with respect to the optical axis L3 is set to an angle at which the index projection light from the light source 41 and the return light from the subject's eye E can pass through a concave mirror 85 of the light-guiding optical system 80, which will be described later. For example, the angle α is 10 degrees or less, and in the present disclosure, the angle α is set to 6 degrees. The image sensor 48 of the second detection optical system 40b can detect the alignment state in the Z direction with the required accuracy even with the projection optical axis and the detection optical axis having such a narrow angle α.

[0064] <Internal configuration of optometry device and light guiding optical system> The internal configuration of the optometry device 1 will be described. Fig. 3 is a schematic diagram of the inside of the optometry device 1 as viewed from the front. Fig. 4 is a schematic diagram of the inside of the optometry device 1 as viewed from the side. Fig. 5 is a schematic diagram of the inside of the optometry device 1 as viewed from above. For ease of explanation, Figs. 4 and 5 only show the optical axis of the left eye measurement unit 7L.

[0065] The optometry apparatus 1 includes a light-guiding optical system 80 that guides an image of a visual target light beam from the measurement unit 7 to the eye to be examined. The light-guiding optical system 80 of this embodiment includes a deflection mirror 81, which is an example of a light deflection member, a reflecting mirror 84, a concave mirror 85, etc. The optometry apparatus 1 also includes a drive mechanism 82 and a drive unit 83 as components related to the light-guiding optical system 80.

[0066] The concave mirror 85 is equivalent to the optical system of the measurement unit 7 (the alignment detection optical system 50A, the objective measurement optical system 10, etc.) being optically positioned at a predetermined working distance in front of the eye when alignment is completed. In the eye examination device 1, the light guiding optical system 80 is configured so that alignment and measurement are performed in an open state in front of the subject's eye by the concave mirror 85 of the light guiding optical member without positioning the optical system of the measurement unit 7 in front of the subject's eye. In addition, during subjective measurement, the light guiding optical system 80 guides the image of the visual target light beam via the correction optical system 60 to the subject's eye so that it is optically at a predetermined examination distance.

[0067] The light-guiding optical system 80 is not limited to this configuration. For example, the light-guiding optical system 80 may be configured without the reflecting mirror 84. In this case, the visual target light beam from the measurement unit 7 may be irradiated from an oblique direction with respect to the optical axis L of the concave mirror 85 after passing through the deflection mirror 81. In addition, for example, the light-guiding optical system 80 may be configured with a half mirror. In this case, the visual target light beam from the measurement unit 7 may be irradiated from an oblique direction with respect to the optical axis L of the concave mirror 85 through the half mirror, and the reflected light beam may be guided to the subject's eye E.

[0068] The optometry device 1 has a left eye drive unit 9L and a right eye drive unit 9R, and can move the left eye measurement unit 7L and the right eye measurement unit 7R in the X direction (horizontal direction). For example, by moving the left eye measurement unit 7L and the right eye measurement unit 7R in the X direction, the distance between the measurement unit 7 and a deflection mirror 81 described later changes, and the presentation position of the visual target light beam from the measurement unit 7 in the Z direction (front-back direction with respect to the subject) is changed. As a result, the visual target light beam corrected by the correction optical system 60 is guided to the subject's eye E, and the measurement unit 7 is adjusted in the Z direction so that an image of the visual target light beam corrected by the correction optical system 60 is formed on the fundus of the subject's eye E.

[0069] For example, the deflection mirror 81 has a right-eye deflection mirror 81R and a left-eye deflection mirror 81L that are provided in a pair on the left and right sides. For example, the deflection mirror 81 is disposed between the measurement unit 7 and the subject's eye E. In this embodiment, the deflection mirror 81R is disposed between the measurement unit 7R and the subject's eye ER, and the deflection mirror 81L is disposed between the measurement unit 7L and the subject's eye EL. That is, the deflection mirror 81 is disposed in a shared optical path of the objective optical system 10 and the target projection optical system 30 of the measurement unit 7. The deflection mirror 81 is also disposed in the optical path of the subjective measurement optical system 25. It is preferable that the deflection mirror 81 is disposed at a pupil conjugate position.

[0070] For example, the left-eye deflection mirror 81L reflects the light beam projected from the left-eye measurement unit 7L and guides it to the left eye EL. Also, for example, the left-eye deflection mirror 81L reflects the fundus reflection light beam from the left eye EL and guides it to the left-eye measurement unit 7L. For example, the right-eye deflection mirror 81R reflects the light beam projected from the right-eye measurement unit 7R and guides it to the right eye ER. Also, for example, the right-eye deflection mirror 81R reflects the fundus reflection light beam from the right eye ER and guides it to the right-eye measurement unit 7R. Note that in this embodiment, a configuration using the deflection mirror 81 as a deflection member that reflects and guides the light beam projected from the measurement unit 7 to the subject's eye E is described as an example, but is not limited to this. The deflection member may be, for example, a prism, a lens, etc., as long as it can reflect and guide the light beam projected from the measurement unit 7 to the subject's eye E.

[0071] For example, the drive mechanism 82 is composed of a motor (drive unit) and the like. For example, the drive mechanism 82 has a drive mechanism 82L for driving the left-eye deflection mirror 81L and a drive mechanism 82R for driving the right-eye deflection mirror 81R. For example, the deflection mirror 81 rotates when driven by the drive mechanism 82. For example, the drive mechanism 82 rotates the deflection mirror 81 about a horizontal rotation axis (X direction) and a vertical rotation axis (Y direction). That is, the drive mechanism 82 rotates the deflection mirror 81 in the XY directions. Note that the rotation of the deflection mirror 81 may be either the horizontal direction or the vertical direction.

[0072] For example, the drive unit 83 is composed of a motor or the like. For example, the drive unit 83 has a drive unit 83L for driving the left-eye deflection mirror 81L and a drive unit 83R for driving the right-eye deflection mirror 81R. For example, the deflection mirror 81 moves in the X direction by being driven by the drive unit 83. For example, the left-eye deflection mirror 81L and the right-eye deflection mirror 81R are moved, so that the distance between the left-eye deflection mirror 81L and the right-eye deflection mirror 81R is changed, and the distance in the X direction between the left-eye optical path and the right-eye optical path can be changed according to the interpupillary distance of the test eye E.

[0073] For example, a plurality of deflection mirrors 81 may be provided in each of the optical path for the left eye and the optical path for the right eye. For example, two deflection mirrors may be provided in each of the optical path for the left eye and the optical path for the right eye (for example, two deflection mirrors may be provided in the optical path for the left eye). In this case, one deflection mirror may be rotated in the X direction, and the other deflection mirror may be rotated in the Y direction. For example, the deflection mirror 81 is rotated to deflect an apparent light beam for forming an image of the visual target light beam in front of the eye E to optically correct the formation position of the image of the visual target light beam.

[0074] For example, the concave mirror 85 is shared by the left eye measurement unit 7L and the right eye measurement unit 7R. For example, the concave mirror 85 is shared by the left eye optical path including the left eye correction optical system and the right eye optical path including the right eye correction optical system. That is, the concave mirror 85 is disposed at a position where it passes through both the left eye optical path including the left eye correction optical system and the right eye optical path including the right eye correction optical system. Of course, the concave mirror 85 does not have to be configured to be shared by the left eye optical path and the right eye optical path. For example, a concave mirror may be provided in each of the left eye optical path including the left eye correction optical system and the right eye optical path including the right eye correction optical system. For example, the concave mirror 85 guides the visual target light beam corrected by the correction optical system 60 to the test eye E so as to optically set the visual target light beam to a predetermined test distance. That is, the light-guiding optical system 80 including the concave mirror 85 allows the subject's eyes to be opened without placing the correction optical system 60 in front of the subject's eyes.

[0075] For example, the concave mirror 85 is used for both the subjective measurement unit and the objective measurement unit. For example, the visual target light beam projected from the subjective measurement optical system 25 is projected onto the subject's eye via the concave mirror 85. Also, for example, the measurement light projected from the objective measurement optical system 10 is projected onto the subject's eye via the concave mirror 85. Also, for example, the reflected light of the measurement light projected from the objective measurement optical system 10 is guided to the light receiving optical system 10b of the objective measurement optical system 10 via the concave mirror 85. In this embodiment, the reflected light of the measurement light by the objective measurement optical system 10 is guided to the light receiving optical system 10b of the objective measurement optical system 10 via the concave mirror 85, but is not limited thereto. The reflected light of the measurement light by the objective measurement optical system 10 may be configured not to pass through the concave mirror 85.

[0076] <Optical path of subjective measurement unit> The optical path of the subjective measurement unit will be described. The subjective measurement unit guides the visual target light beam to the subject's eye E by reflecting the visual target light beam passing through the correction optical system 60 toward the subject's eye by the concave mirror 85, and forms an image of the visual target light beam passing through the correction optical system 60 in front of the subject's eye so as to be optically at a predetermined test distance. That is, the concave mirror 85 reflects the visual target light beam so as to make it a substantially parallel light beam. Therefore, the visual target image seen by the subject appears to be farther away than the actual distance from the subject's eye E to the display 31. That is, by using the concave mirror 85, the visual target image can be presented to the subject so that the image of the visual target light beam can be seen at a position at a predetermined test distance.

[0077] A more detailed description will be given. In the following description, the optical path for the left eye will be taken as an example. The optical path for the right eye has the same configuration as the optical path for the left eye. For example, in a subjective measurement for the left eye, the visual target light beam projected from the display 13 of the measurement unit for the left eye 7L enters the astigmatism correction optical system 63 via the projection lens 33. The visual target light beam that passes through the astigmatism correction optical system 63 is projected from the measurement unit for the left eye 7L toward the deflection mirror for the left eye 81L via the reflection mirror 36, the dichroic mirror 35, and the dichroic mirror 29. The visual target light beam emitted from the measurement unit for the left eye 7L and reflected by the deflection mirror for the left eye 81 is reflected by the reflection mirror 84 toward the concave mirror 85. The visual target light beam reflected by the concave mirror reaches the left eye EL.

[0078] As a result, a target image corrected by the correction optical system 60 is formed on the fundus of the left eye EL of the examinee based on the eyeglass wearing position of the left eye EL of the examinee (for example, about 12 mm from the corneal apex). This is equivalent to the astigmatism correction optical system 63 being placed in front of the eye, and the spherical power being adjusted by the spherical power correction optical system (in this embodiment, driven by the drive mechanism 39) being performed in front of the eye, and the examinee can collimate the image of the target in a natural open state through the concave mirror 85. The optical path for the right eye is also configured in the same way as the optical path for the left eye, and target images corrected by the pair of right and left correction optical systems 60 are formed on the fundus of both examinee's eyes based on the eyeglass wearing positions of the left and right examinee's eyes E (for example, about 12 mm from the corneal apex). In this way, the examinee responds to the examiner while looking directly at the target in a natural state of vision, and performs correction by the correction optical system 60 until the test target looks appropriate, and the optical characteristics of the examinee's eyes are measured subjectively based on the correction value.

[0079] <Optical path of objective measurement unit> The optical path of the objective measurement section will be described. In the following description, the optical path for the left eye will be taken as an example, but the optical path for the right eye has the same configuration as the optical path for the left eye. For example, in the objective measurement section for the left eye, the measurement light emitted from the light source 11 of the projection optical system 10a in the objective measurement optical system 10 passes through the relay lens 12 and the dichroic mirror 29, and is projected from the measurement section 7L for the left eye toward the deflection mirror 81L for the left eye. The measurement light emitted from the measurement section 7L for the left eye and reflected by the deflection mirror 81 for the left eye is reflected by the reflection mirror 84 toward the concave mirror 85. The measurement light reflected by the concave mirror reaches the left eye EL and forms a spot-shaped point light source image on the fundus of the left eye EL. At this time, the prism 15 rotating around the optical axis causes the pupil projection image (projection light beam on the pupil) of the hole part of the hole mirror 13 to be eccentrically rotated at high speed.

[0080] The light of the point light source image formed on the fundus of the left eye EL is reflected and scattered, exits the subject's eye E, travels along the optical path through which the measurement light passed, is collected by the objective lens 14, and reaches the prism 15, the hole mirror 13, the relay lens 16, and the mirror 17. The light reflected by the mirror 17 is collected again on the opening of the light receiving diaphragm 18, is made into a substantially parallel beam (in the case of an emmetropic eye) by the collimator lens 19, is extracted as a ring-shaped beam by the ring lens 20, and is received as a ring image by the image sensor 22. The optical characteristics of the subject's eye E can be objectively measured by analyzing the received ring image.

[0081] <Control Unit> FIG. 6 is a diagram showing a control system of the optometry apparatus 1. For example, the control unit 70 is connected to each of electrical elements such as the imaging unit 90, the anterior eye illumination unit 92, the display 6a of the controller 6, the switch unit 6b, the light source 11 of the measurement unit 7, the imaging element 22, the display 31, the imaging element 52, the drive mechanism 39, the rotation mechanism 62a, the rotation mechanism 62b, the light source 56 of the first target projection optical system 55, the light source 41 and the imaging element 48 of the second target projection optical system 40a, the drive mechanism 82 of the light guiding optical system 80, and the drive unit 83. Also, the control unit 70 is connected to a memory 75 (for example, a non-volatile memory) and a printer 77, which are examples of a storage means. For example, the memory 75 is a non-transient storage medium that can retain the stored contents even if the power supply is cut off. For example, a hard disk drive, a flash ROM, a USB memory, or the like can be used as the memory 75. The measurement results are printed out from the printer 77.

[0082] For example, the control unit 70 includes a CPU (processor), RAM, ROM, etc. For example, the CPU controls each component in the optometry device 1. For example, the RAM temporarily stores various information. For example, the ROM stores various programs, optotypes, initial values, etc. for controlling the operation of the optometry device 1. The control unit 70 may be configured with multiple control units (i.e., multiple processors). The control unit 70 may also include an FPGA (field-programmable gate array) 70a. The FPGA 70a allows the device designer to freely set the control configuration. The control unit 70 also functions as a display control means for controlling the display on the display 6a and the display 31. The control unit 70 also functions as a measurement control means for controlling the driving of the drive system (drive mechanism 39, rotation mechanism 62a, rotation mechanism 62b) of the correction optical system 60. The control unit 70 also functions as an alignment control means for controlling the driving of the drive mechanism 82 and drive unit 83 of the light-guiding optical system 80.

[0083] <Operation> The operation of the eye examination device 1 having the above-mentioned configuration will be described. The subject places his / her forehead on the forehead rest 4 and observes the presentation window 3. When the subject is ready for the examination, the examiner operates the touch panel (or the switch unit 6b) of the display 6a of the controller 6 to input a selection signal of an optotype (fixation target) for fixating the subject's eye E. The control unit 70 causes the display 31 provided on each of the left eye measurement unit 7L and the right eye measurement unit 7R to display the same optotype based on the selection signal of the optotype. Optotypes are presented to the left and right subject's eyes E (left eye EL and right eye ER), respectively, but by presenting the same optotype, the subject recognizes it as one optotype with both eyes. In the case of one-eye measurement, the optotype is displayed only on the display 31 on the measurement eye side.

[0084] <Alignment of the measurement unit to the test eye> Next, the examiner inputs a start signal for aligning the left eye measurement unit 7L and the right eye measurement unit 7R to the left eye EL and right eye ER of the examinee, respectively, through the touch panel of the display 6a (or the switch unit 6b). An index by the first index projecting optical system 55 and an index by the second index projecting optical system 40a are projected onto the left eye EL and right eye ER, respectively. This operates an automatic alignment means that aligns the measurement unit 7 including the objective measurement optical system 10 and the like to a predetermined positional relationship three-dimensionally with respect to the examinee's eye E. The operation of the automatic alignment means will be described below.

[0085] The index by the light source 56 projected onto the subject's eye by the first index projection optical system 55 is received by the image sensor 52, and the alignment state of the measurement unit 7 in the XY direction is detected based on the output signal from the image sensor 52. Also, the index by the light source 41 projected onto the subject's eye by the second index projection optical system 40a is received by the image sensor 48, and the alignment state of the measurement unit 7 in the Z direction is detected based on the output signal from the image sensor 48.

[0086] Here, when imaging by the imaging elements 52 and 48 is performed by normal processing, in addition to the index (corneal reflection bright spot) by the light source 56, the index (corneal reflection bright spot) by the light source 41 is incident on the imaging element 52. For this reason, it is difficult for the control unit 70 to properly detect the alignment state in the XY directions by distinguishing only the index by the light source 56. Furthermore, in addition to the index by the light source 41, the index by the light source 56 and illumination light by the anterior eye illumination unit 92 enter the imaging element 48. In this case as well, it is difficult for the control unit 70 to properly detect the alignment state in the Z direction by distinguishing only the index by the light source 41.

[0087] Therefore, the control unit 70 of the present disclosure controls the timing of each exposure time of the image sensor 52 and the image sensor 48 so that the exposure time of the image sensor 52 and the exposure time of the image sensor 48 do not overlap. For example, the control unit 70 controls the timing of the start of each exposure of the image sensor 52 and the image sensor 48. More preferably, the control unit 70 controls the exposure time of the image sensor 52 and the image sensor 48 at a time shorter than the frame interval (time of one frame) of a predetermined frame rate. More preferably, the control unit 70 adjusts the relationship of the frame phase of each exposure time of the image sensor 52 and the image sensor 48. In addition, the control unit 70 controls the lighting of the light source 56 and the light source 41 in accordance with each exposure time of the image sensor 52 and the image sensor 48. When the anterior eye illumination unit 92 is used, the control unit 70 also controls the lighting of the anterior eye illumination unit 92 in accordance with each exposure time of the image sensor 52 and the image sensor 48.

[0088] FIG. 7 is a diagram for explaining an example of control of the timing of exposure time (timing of start and end of exposure) of the image sensor 52 and the image sensor 48, and the timing of lighting (timing of start and end of lighting) of each light source (light source 56, light source 41, anterior eye illumination unit 92). In FIG. 7, a figure G52 shows the chronological timing of the frame interval FR (time of one frame) and the frame output Fo (output of an exposed frame) of the image sensor 52. For example, the frame rate of the image sensor 52 is 30 fps (number of frames per second), and the frame interval FR is about 33 ms (milliseconds). A figure G48 shows the chronological timing of the frame interval FR and the frame output Fo of the image sensor 48. For example, the frame rate of the image sensor 48 is 30 fps, the same as that of the image sensor 52, and the frame interval FR is about 33 ms.

[0089] In FIG. 7, a figure G52ET indicates the timing of the exposure time Eta of the image sensor 52 with respect to the frame interval FR of the figure G52. The exposure time Eta of the image sensor 52 is shorter than the frame interval FR, and is controlled by the FPGA 70a of the control unit 70 to half the frame interval FR (approximately 16.6 ms). Also in FIG. 7, a figure G48ET indicates the timing of the exposure time Etb of the image sensor 48 with respect to the frame interval FR of the figure G48. The exposure time Etb of the image sensor 48 is also shorter than the frame interval FR, and is controlled by the FPGA 70a to half the frame interval FR (approximately 16.6 ms). Then, the FPGA 70a sets the shift amount Ph of the frame phase of the image sensor 48 with respect to the frame phase of the image sensor 52 to the amount of the exposure time Etb so that the exposure time Eta of the image sensor 52 and the exposure time Etb of the image sensor 48 do not overlap in terms of timing.

[0090] Also, the lighting time G56ON of the light source 56 used for alignment in the XY directions is controlled to be synchronized with the exposure time Eta of the image sensor 52. In other words, during the exposure time Etb of the image sensor 48, the lighting time G92ON of the anterior eye illumination unit 92 used for anterior eye observation is also controlled to be synchronized with the exposure time Eta of the image sensor 52. In other words, during the exposure time Etb of the image sensor 48, the lighting time G92ON of the anterior eye illumination unit 92 used for anterior eye observation is controlled to be synchronized with the exposure time Eta of the image sensor 52. In other words, during the exposure time Etb of the image sensor 48, the lighting time G41ON of the light source 41 used for alignment in the Z direction is controlled to be synchronized with the exposure time Etb of the image sensor 48. In other words, during the exposure time Eta of the image sensor 52 ...

[0091] By controlling the exposure times of the image sensor 52 and the image sensor 48 and controlling the illumination of the light source 56 and the light source 41 as described above, the index by the light source 56 used for alignment in the XY direction is incident on the image sensor 52, but the index by the light source 41 used for alignment in the Z direction is not incident on the image sensor 52. Therefore, the control unit 70 analyzes the position of the index 56I imaged by the image sensor 52 as shown in Fig. 8, thereby appropriately detecting the alignment state of the measurement unit 7 in the XY direction with respect to the subject's eye. Fig. 8 is an example of an image 52I imaged by the image sensor 52, and in the image 52I, the index 56I formed by reflection of the cornea of ​​the subject's eye is imaged in the anterior eye image EFI of the subject's eye E illuminated by the anterior eye illumination unit 92.

[0092] Further, the index by the light source 41 used for alignment in the Z direction is incident on the image sensor 48, but the index by the light source 56 and the illumination light by the anterior eye illumination unit 95 are not incident on the image sensor 48. Therefore, as shown in Fig. 9, the control unit 70 analyzes the position of the index 41I imaged by the image sensor 48, and the alignment state of the measurement unit 7 in the Z direction with respect to the subject's eye is appropriately detected. Fig. 9 is an example of an image 48I imaged by the image sensor 48. Since the anterior eye illumination unit 92 is turned off during the exposure time of the image sensor 48, the anterior eye image of the subject's eye E is not imaged as in Fig. 8, and the index 56I formed by reflection of the cornea of ​​the subject's eye is imaged against a dark background.

[0093] In addition, since the frame phase of the imaging element 48 is shifted relative to the frame phase of the imaging element 52, the images captured by the imaging elements 52 and 48 are not output simultaneously but are output in sequence, allowing efficient analysis of each image.

[0094] The control unit 70 controls the driving of the driving mechanism 82 (82L, 82R) and the driving unit 83 (83L, 83R) based on the detection result of the index 56I imaged by the imaging element 52, and automatically adjusts the alignment in the XY direction. The control unit 70 also controls the driving of the driving unit 9 (9L, 9R) based on the detection result of the index 56I imaged by the imaging element 48, and automatically adjusts the alignment in the Z direction. When the position of the index 56I falls within a predetermined allowable range with respect to the reference position in the XY direction on the imaging element 52, and when the position of the index 56I falls within a predetermined allowable range with respect to the reference position in the Z direction on the imaging element 48, the control unit 70 determines that the alignment of the measurement unit 7 with respect to the subject's eye E is completed. Then, when the alignment with respect to the subject's eye E is completed, the control unit 70 issues a trigger signal for starting the objective ocular refractive power measurement (objective measurement), and automatically executes the ocular refractive power measurement by the objective measuring optical system 10 (executes the auto shot).

[0095] The control unit 70 emits measurement light beams from the objective measurement optical system 10. In this case, each measurement light beam is reflected by the concave mirror 85 via the deflection mirrors 81R and 81L, and then projected onto the fundus of the subject's eye. The measurement light reflected from the fundus passes through the concave mirror 85 and the deflection mirrors 81R and 81L, and measurement images are captured by the imaging elements 22 of the left and right measurement units 7.

[0096] For example, in the measurement of objective ocular refraction, a preliminary measurement of ocular refraction may be performed first, and the display 31 may be moved in the optical axis L2 direction based on the result of the preliminary measurement to fog the test eye E. Then, the main measurement of ocular refraction may be performed on the fogged test eye. In the main measurement, a measurement image is captured by the imaging element 22, and an output signal from the imaging element 22 is stored in the memory 75 as image data (measurement image). Then, the control unit 70 performs image analysis on the ring image stored in the memory 75 to obtain the value of the refraction in each meridian direction. The control unit 70 performs a predetermined process on this refraction to obtain the objective ocular refraction (objective value) of the test eye for distance use of S (spherical power), C (cylindrical power), and A (cylindrical axis angle). The obtained objective value for distance use is stored in the memory 75. The objective refractive power of the subject's eyes may be measured simultaneously for both the left and right eyes, or separately for both the left and right eyes.

[0097] The objective eye refractive power is measured multiple times (for example, three times) for each of the left and right eyes to be examined. When performing these multiple measurements, if the alignment state deviates from a predetermined allowable range due to the movement of the eye to be examined even after the alignment adjustment in the XYZ directions is completed, the control unit 70 controls the driving of the drive unit 9, the drive mechanism 82, and the drive unit 83 so that the alignment state falls within the predetermined allowable range again. In other words, automatic tracking of the alignment is performed.

[0098] In judging the completion of alignment and automatically tracking the alignment as described above, the exposure of both the image sensor 52 and the image sensor 48 is performed within a frame interval (e.g., 33 ms), so that both the index detection by the image sensor 52 and the index detection by the image sensor 48 are performed at a predetermined frame rate (e.g., 30 fps). Therefore, even though the alignment state in the XYZ directions is detected using the image sensor 52 and the image sensor 48, the detection results of the index by the light source 56 and the index by the light source 41 can be obtained within the same frame rate as in the case of alignment detection at the frame rate of one image sensor 52. This allows the completion of alignment to be appropriately judged without delay in judging the detection of the alignment state.

[0099] Here, if the light source 56 and the light source 41 are alternately turned on at a frame interval FR, and the exposure time of the image sensor 52 and the image sensor 48 is kept at the normal frame interval FR, the detection of the index of the light source 56 captured by the image sensor 52 and the detection of the index of the light source 41 captured by the image sensor 48 are each at a timing half the predetermined frame rate (for example, 15 fps). In this case, the determination of the completion of alignment is delayed due to nystagmus, blinking, etc. of the subject's eye, and as a result, the timing determination of the measurement is also delayed, which is likely to affect the measurement result, such as the measurement value being confirmed as incorrect. In contrast, in the present disclosure, as described above, the detection of the index of the light source 56 captured by the image sensor 52 and the detection of the index of the light source 41 captured by the image sensor 48 are each performed at a predetermined frame rate (for example, 30 fps), so that the completion of alignment can be determined in a timely manner, and the measurement is performed without delaying the timing determination of the measurement execution. As a result, a highly reliable measurement result can be obtained without reducing the accuracy of the measurement result.

[0100] In this embodiment, the configuration for adjusting the alignment in the XYZ directions by driving the deflection mirror 81 by the driving mechanism 82 and the driving unit 83 and moving the measurement unit 7 by the driving unit 9L and the driving unit 9R has been described as an example, but the present invention is not limited to this. Any configuration may be used as long as it can adjust the positional relationship between the subject's eye and the measurement unit 7. For example, a configuration may be provided in which the housing 2 in which the measurement unit 7 is arranged can be moved in the XYZ directions relative to the chin rest 6, and the housing 2 is moved. In this case, a configuration for moving the left eye deflection mirror 81L and the right eye deflection mirror 81R in the X direction may be provided. This allows the left and right directions of the optical axes of the measurement units 7L and 7R to be adjusted in accordance with the interpupillary distance of the subject. In addition, for example, a configuration may be used in which the adjustment in the XYZ directions can be performed only by the deflection mirror 81. In this case, for example, a configuration may be used in which the deflection mirror 81 is rotated and moved in the Z direction so that the distance between the measurement unit 7 is changed.

[0101] <Example of transformation> Although typical examples of the present disclosure have been described above, the present disclosure is not limited to the above-described examples and various modifications are possible.

[0102] For example, in the description of FIG. 7, the exposure time Eta of the image sensor 52 and the exposure time Etb of the image sensor 48 are each set to half the frame interval FR, but the present invention is not limited thereto. The exposure times Eta and Etb may be shorter than the frame interval FR, and the total time of the exposure times Eta and Etb may be equal to or shorter than the frame interval FR. For example, when the luminance of the index 56I (index by the light source 56) captured by the image sensor 52 is lower than that of the index 41I (index by the light source 41) captured by the image sensor 48, and the detection accuracy of the index 56I by image analysis is reduced, the exposure time Eta of the image sensor 52 is set to be longer than the exposure time Etb of the image sensor 48 so that the luminance of the index 41I increases. For example, the exposure time Eta may be set to 2 / 3 of the frame interval FR (for example, about 22.2 ms), and the exposure time Etb may be set to 1 / 3 of the frame interval FR (for example, about 11.1 ms). The frame phase shift amount Ph of the image sensor 48 is set to be the same as the exposure time Etb. The illumination time G56ON of the light source 56 and the illumination time G92ON of the anterior eye illumination unit 92 are also controlled to be synchronized with the exposure time Eta of the image sensor 52, and the illumination time G41ON of the light source 41 is controlled to be synchronized with the exposure time Etb of the image sensor 48. This increases the index 56I, and the alignment state can be detected more appropriately.

[0103] 7, the timing of the exposure time Eta of the image sensor 52 and the exposure time Etb of the image sensor 48 with respect to the frame interval FR is immediately before the frame output Fo, but this is not limited to this. For example, if control can be established that can arbitrarily change the timing of the exposure times within the frame interval FR of the image sensors 52 and 48, it is not necessary to shift the frame phase relationship between the image sensors 52 and 48. For example, the exposure time Eta of the image sensor 52 may be set to the timing of the first half of the frame interval FR, and the exposure time Etb of the image sensor 48 may be set to the timing of the second half of the frame interval FR.

[0104] In the above description of FIG. 2, the detector of the second detection optical system 40b is the imaging element 48 of an area sensor, but since detection is performed in one direction, the front-back direction (Z direction), the detector of the second detection optical system 40b may be a line sensor. Even if a line sensor is used, its exposure time may be controlled to be the same as the exposure time Etb of the imaging element 48 shown in FIG. The line sensor can be treated as one of the horizontal lines of the imaging element 48, which is an area sensor. Therefore, by making the exposure time of the line sensor the same as the exposure time Etb of the imaging element 48, it is possible to detect an index with the same brightness as the detection of the index by the imaging element 48, and the alignment state can be more appropriately determined.

[0105] When a line sensor is used, a cylinder lens may be used instead of the condenser lens 47 of the second detection optical system 40b. The cylinder axis of the cylinder lens may be arranged so that the index light beam condensed in a line is perpendicular to the longitudinal direction of the line sensor. This allows the index light beam displaced in the Z direction to be incident on the line sensor even if there is a misalignment in the XY directions of the eye to be examined.

[0106] In the above embodiment, the light source 56 and the light source 41 are controlled to project the index 41I by the light source 41 onto the subject's eye during the exposure time of the image sensor 52, and the index 56I onto the subject's eye during the exposure time of the image sensor 48. However, the present invention is not limited to this. For example, a mechanical or electronic shutter may be provided on the optical path of the index projection of the light source 41 and the optical path of the index projection of the light source 56, and the opening and closing of each shutter may be controlled to prevent the index 41I, which becomes noise, from being projected during the exposure time of the image sensor 52, and the index 56I, which becomes noise, from being projected during the exposure time of the image sensor 48. Similarly, a mechanical or electronic shutter may be provided on the illumination optical path of the anterior eye illumination unit 92. [Explanation of symbols]

[0107] 1 Optometry equipment 10 Objective Measuring Optical System 11 Light source 22 Image sensor 29 Dichroic Mirror 40a 2nd target projection optical system 48 Image sensor 50 Observation Optical System 50A Alignment detection optical system 52 Image sensor 55 First target projection optical system 70 Control unit 80 Light guiding optical system 85 Concave Mirror

Claims

1. An ophthalmic apparatus comprising inspection means for inspecting an eye to be examined, alignment detection means for detecting the alignment state of the inspection means with respect to the eye to be examined, control means for controlling the operation of the ophthalmic apparatus, and the alignment detection means includes first index projection means for projecting a first index for aligning the inspection means in a first direction of at least one of the left-right, up-down, and front-back directions with respect to the eye to be examined onto the eye to be examined, a first detector for detecting the first index projected onto the eye to be examined, second index projection means for projecting a second index for aligning the inspection means in a second direction which is at least one of the left-right, up-down, and front-back directions with respect to the eye to be examined and which is different from the first direction, and a second detector for detecting the second index projected onto the eye to be examined, wherein the control means controls the exposure times of the first detector and the second detector to be shorter than the frame interval and such that the timings of their respective exposure times do not overlap, characterized in that it is an ophthalmic apparatus.

2. In the ophthalmic apparatus according to Claim 1, the control means controls the first index projection means and the second index projection means such that the second index is not projected onto the eye to be examined during the exposure time of the first detector and the first index is not projected onto the eye to be examined during the exposure time of the second detector, characterized in that it is an ophthalmic apparatus.

3. In the ophthalmic apparatus according to Claim 1, the control means adjusts the relationship of the frame phases of the first detector and the second detector such that the timings of the exposure times of the first detector and the second detector do not overlap, characterized in that it is an ophthalmic apparatus.

4. In the ophthalmic apparatus according to Claim 1, the control means controls such that the total time of the exposure time of the first detector and the exposure time of the second detector within the frame interval is within the time of the frame interval, characterized in that it is an ophthalmic apparatus.

5. In the ophthalmic apparatus according to any one of Claims 1 to 4, the inspection means includes an inspection optical system having an inspection light source for projecting inspection light onto the eye to be examined and an inspection light receiving element for receiving the return light of the inspection light from the eye to be examined, and the inspection optical system includes first wavelength limiting means for limiting the wavelength of the return light of the first index and the second index used for alignment from the eye to be examined to enter the inspection light receiving element. The ophthalmic apparatus is characterized in that the alignment detection means includes second wavelength limiting means for limiting the wavelength of the return light from the eye to be examined of the inspection light from entering the first detector and the second detector.

6. In the ophthalmic apparatus according to any one of Claims 1 to 4, the inspection means includes an inspection optical system having an inspection light source that projects inspection light onto the eye to be examined and an inspection light receiving element that receives the return light of the inspection light from the eye to be examined, the ophthalmic apparatus is a light guiding optical system that guides the index lights of the first index and the second index to the eye to be examined and guides the return light of the index lights from the eye to be examined to the first detector and the second detector, and has a light guiding optical system that guides the inspection light from the inspection optical system to the eye to be examined and guides the return light of the inspection light from the eye to be examined to the inspection optical system, the ophthalmic apparatus is configured such that alignment and inspection are performed in an open state in front of the eyes of the subject by the light guiding optical system.

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