Ophthalmic device and control method thereof

Abstract

To provide an ophthalmologic apparatus which can carry out alignment easily in a short time while preventing contact of an ocular characteristic acquisition part with a face of a subject during the alignment, and a controlling method thereof.SOLUTION: An ophthalmologic apparatus includes: a detection control part 60a which continues output of a detection signal by a relative position detection part (a Z alignment detection optical system 26) in performing alignment; a non-contact type sensor (a capacitance sensor 36) which can detect the approach of an ocular characteristic acquisition part to a face of a subject in a non-contact manner; a determination part 60b which continuously determines whether a detection value of the non-contact type sensor is greater than a threshold value or not in performing the alignment; and a risk avoiding operation control part (a stop control part 60c) which performs a risk avoiding operation when the relative position detection part cannot detect a relative position, and the determination part determines that the detection value is greater than the threshold value. When the relative position detection part detects the relative position, or the determination part determines that the detection value is not greater than the threshold value, the alignment is continued.SELECTED DRAWING: Figure 14

Description

[Technical Field]

[0001] The present invention relates to an ophthalmic apparatus for measuring eye characteristics of a subject's eye and a control method thereof. [Background technology]

[0002] A non-contact tonometer, which measures the intraocular pressure of a subject's eye without contact, is known as one type of ophthalmic device for acquiring (measuring, photographing, observing, etc.) the ocular characteristics of the subject's eye. A non-contact tonometer measures the intraocular pressure of the subject's eye without contacting the cornea by spraying air (fluid) from a nozzle toward the cornea of ​​the subject's eye to deform the cornea and detecting the state of deformation. Before starting to measure the intraocular pressure of the subject's eye using this non-contact tonometer, the measurement head (nozzle) is aligned with the subject's eye, but during this alignment, it is necessary to prevent contact between the nozzle and the subject's eye or the subject's face.

[0003] Therefore, Patent Document 1 describes an ophthalmic device having a measurement head equipped with a detection sensor capable of detecting approach or contact of the measurement head with respect to the face of the subject (eye to be examined). The ophthalmic device described in Patent Document 1 retracts the measurement head from the face of the subject when the detection sensor detects approach or contact of the measurement head with the face of the subject.

[0004] Patent Document 2 describes an ophthalmic device having a measurement head equipped with a detection sensor similar to that of Patent Document 1. The ophthalmic device described in Patent Document 2 increases the working distance between the measurement head and the subject's eye when the detection sensor detects that the measurement head is approaching or contacting the subject's face.

[0005] Patent Document 3 describes an ophthalmologic apparatus having a measurement head equipped with a detection sensor that detects the approach of the measurement head to the face of a subject. The ophthalmologic apparatus described in Patent Document 3 is switchable between a first mode (auto mode) in which, when the detection sensor detects the approach of the measurement head to the face of a subject, an operation to avoid this approach is performed, and a second mode (manual mode) in which the operation to avoid this approach is not performed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 7-255677 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-187024 [Patent Document 3] Patent Publication No. 2021-41092 Summary of the Invention [Problem to be solved by the invention]

[0007] Incidentally, when a detection sensor is provided on the measurement head as in the ophthalmic devices described in Patent Documents 1 to 3, the detection sensor may detect the approach of the face even though there is no risk of the measurement head coming into contact with the face (eye to be examined) depending on the shape of the subject's face, etc. In this case, in the ophthalmic devices described in Patent Documents 1 and 2, the detection sensor is constantly detecting, so that the measurement head is retracted or the working distance is changed every time the detection sensor detects the approach of the face, etc., which takes time for alignment.

[0008] In addition, the ophthalmologic apparatus described in Patent Document 3 requires switching from the first mode to the second mode and manual alignment in the second mode every time the detection sensor detects the approach of a face, which takes time for alignment. Furthermore, the ophthalmologic apparatus described in Patent Document 3 requires switching modes every time the detection sensor detects the approach of a face, which makes the examiner's work complicated.

[0009] The present invention has been made in consideration of the above circumstances, and aims to provide an ophthalmic apparatus and a control method thereof that can perform alignment easily and in a short time while preventing the eye characteristic acquisition unit from coming into contact with the subject's face during alignment. [Means for solving the problem]

[0010] An ophthalmic device for achieving the object of the present invention comprises an ophthalmic characteristic acquisition unit that acquires the ocular characteristics of the subject's eye, a drive mechanism that moves the ocular characteristic acquisition unit relative to the subject's eye, a relative position detection unit that detects the relative position of the subject's eye relative to the ocular characteristic acquisition unit, an alignment control unit that automatically drives the drive mechanism based on the relative position detection result by the relative position detection unit or drives the drive mechanism in accordance with manual operation to align the ocular characteristic acquisition unit with the subject's eye, a detection control unit that continues detection of the relative position by the relative position detection unit while alignment is being performed, one or more non-contact sensors that can detect the approach of the ocular characteristic acquisition unit to the subject's face without contact, a judgment unit that continuously judges whether the detection value of the non-contact sensor has become greater than a predetermined threshold while alignment is being performed, and a danger avoidance operation control unit that performs a predetermined danger avoidance operation when the relative position detection unit is unable to detect the relative position and the judgment unit judges that the detection value has become greater than the threshold, and the alignment control unit continues alignment when the relative position detection unit has detected the relative position or when the judgment unit judges that the detection value has not.

[0011] With this ophthalmic device, danger avoidance action is taken only when the relative position detection unit is unable to detect the relative position during alignment and when the approach of the subject's face is detected using a non-contact sensor and it is determined that there is a possibility that the eye characteristic acquisition unit will come into contact with the subject's face; in all other cases, alignment can be continued.

[0012] In the ophthalmologic apparatus according to another aspect of the present invention, the danger avoidance operation control unit executes the danger avoidance operation when the relative position detection unit has been unable to detect the relative position for a predetermined period of time and the determination unit has determined that the detection value has become greater than a threshold value. This prevents the danger avoidance operation from being started by a blink or a momentary movement of the line of sight of the subject's eye, making it possible to perform alignment easily and in a short time.

[0013] In the ophthalmologic apparatus according to another aspect of the present invention, the danger avoidance operation control unit counts the number of times that the relative position detection unit is unable to detect the relative position, and when the number of times that the detection is unable to detect exceeds a predetermined upper limit and the determination unit determines that the detection value is greater than a threshold, the danger avoidance operation is executed. This prevents the danger avoidance operation from being started by a blink or a momentary movement of the line of sight of the subject's eye, making it possible to perform alignment easily and in a short time.

[0014] In the ophthalmologic apparatus according to another aspect of the present invention, the determination unit makes a determination when the relative position detection unit cannot detect the relative position. As a result, when the relative position detection unit cannot detect the relative position during alignment, the eye characteristic acquisition unit detects the approach of the subject's face using a non-contact sensor as there is a possibility that the eye characteristic acquisition unit will come into contact with the subject's face, and the approach detection can be omitted in other cases.

[0015] In the ophthalmologic apparatus according to another aspect of the present invention, the danger avoidance operation control unit controls the alignment control unit to stop alignment as the danger avoidance operation, and when the alignment control unit stops alignment, controls the drive mechanism to stop relative movement of the ocular characteristic acquisition unit with respect to the subject's eye or to retract the ocular characteristic acquisition unit from the subject's eye, thereby preventing the ocular characteristic acquisition unit from coming into contact with the subject's face.

[0016] In an ophthalmologic apparatus according to another aspect of the present invention, the drive mechanism can move the ocular characteristic acquisition unit relative to the subject's eye in the front-back, left-right, and up-down directions, the relative position detection unit can detect the relative position in each of the three axial directions of the front-back, left-right, and up-down directions, the alignment control unit performs alignment in each of the three axial directions, and the detection control unit and the determination unit operate only while the front-back alignment is being performed. This allows the relative position detection unit to detect the relative position and the determination unit to make a determination only when there is a possibility that the ocular characteristic acquisition unit will come into contact with the subject's face.

[0017] In the ophthalmologic apparatus according to another aspect of the present invention, a notification unit is provided that notifies an examiner of warning information when the relative position detection unit is unable to detect the relative position or when the determination unit determines that the detection value is greater than a threshold value. This makes it possible to notify the examiner that the relative position detection unit is unable to detect the relative position or that the eye characteristic acquisition unit is approaching the face of the examinee.

[0018] In the ophthalmologic apparatus according to another aspect of the present invention, the non-contact sensor is a capacitance sensor.

[0019] In another aspect of the ophthalmic device of the present invention, the eye characteristic acquisition unit is a measurement head of a non-contact tonometer having a nozzle that sprays fluid onto the cornea of ​​the test eye, an anterior eye window glass that holds the tip of the nozzle, and a glass holding unit that holds the anterior eye window glass, and a non-contact sensor is provided in the glass holding unit.

[0020] To achieve the object of the present invention, a control method for an ophthalmologic apparatus includes an ophthalmologic apparatus having an ophthalmic characteristic acquisition unit that acquires ophthalmic characteristics of a subject's eye, a drive mechanism that moves the ophthalmic characteristic acquisition unit relative to the subject's eye, and a relative position detection unit that detects the relative position of the subject's eye with respect to the ophthalmic characteristic acquisition unit, the control method comprising: an alignment control step of automatically driving the drive mechanism based on a detection result of the relative position by the relative position detection unit or by manually driving the drive mechanism to align the ophthalmic characteristic acquisition unit with the subject's eye; and a detection control step of continuing detection of the relative position by the relative position detection unit while the alignment is being performed. The alignment control step includes a determination step in which, during alignment, a determination is continuously made as to whether or not the detection value of one or more non-contact sensors capable of contactlessly detecting the approach of the eye characteristic acquisition unit to the subject's face has become greater than a predetermined threshold value, and a danger avoidance operation step in which, when the relative position detection unit is unable to detect the relative position and it is determined in the determination step that the detection value has become greater than the threshold value, a predetermined danger avoidance operation is performed, and the alignment control step continues alignment when the relative position detection unit has detected the relative position or when it is determined in the determination step that the detection value has not. [Effects of the Invention]

[0021] The present invention makes it possible to perform alignment easily and in a short time while preventing the eye characteristic acquisition unit from coming into contact with the subject's face during alignment. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a side view of a non-contact tonometer according to a first embodiment. [Figure 2] FIG. 2 is a schematic top view of a plurality of types of optical systems in the measurement head as viewed from above. [Figure 3] FIG. 2 is a schematic side view of a plurality of types of optical systems in the measurement head as viewed from the side. [Figure 4] FIG. 2 is a perspective view of the measuring head as seen from the subject side. [Figure 5] 5 is an enlarged front view of the electrodes of the capacitance sensor in FIG. 4. [Figure 6] FIG. 2 is an explanatory diagram for explaining the directionality of a capacitance type sensor. [Figure 7] FIG. 2 is a functional block diagram of a control device. [Figure 8] FIG. 8 is a functional block diagram of an alignment control unit in FIG. 7. [Figure 9] 10 is an explanatory diagram for explaining the execution of coarse XY alignment by a coarse XY alignment control unit. FIG. [Figure 10] FIG. 10 is an explanatory diagram for explaining coarse Z alignment. [Figure 11] FIG. 10 is an explanatory diagram showing the light beams of Z alignment index light and Z index reflected light for each Z direction position of the cornea during fine Z alignment. [Figure 12] 10 is an explanatory diagram showing the incident position of the Z index reflected light onto the light receiving sensor for each position in the Z direction of the cornea, and the signal intensity of the Z detection signal output from the light receiving sensor. FIG. [Figure 13] FIG. 10 is an explanatory diagram for explaining fine XY alignment. [Figure 14] 10 is an explanatory diagram for explaining execution conditions for detecting approach of a subject's face using a capacitance type sensor by a monitoring control unit. FIG. [Figure 15] 10 is an explanatory diagram showing an example of notification of warning information by a notification control unit; FIG. [Figure 16] 4 is a flowchart showing the flow of a process for measuring the intraocular pressure of an eye to be examined using the non-contact tonometer of the first embodiment. [Figure 17] 10 is a flowchart showing the flow of a process for measuring the intraocular pressure of an eye to be examined using a non-contact tonometer according to a second embodiment. [Figure 18] 10 is a flowchart showing the flow of an intraocular pressure measurement process of an eye to be examined using a non-contact tonometer according to a third embodiment. [Figure 19] 10 is a flowchart showing the flow of a process for measuring the intraocular pressure of an eye to be examined by a non-contact tonometer according to a fourth embodiment. [Figure 20] 11 is a flowchart showing the flow of a process for measuring the intraocular pressure of an eye to be examined by a non-contact tonometer according to a fifth embodiment. [Figure 21] FIG. 10 is a block diagram of a non-contact tonometer according to a sixth embodiment. [Figure 22] 13 is a flowchart showing the flow of a process for measuring the intraocular pressure of an eye to be examined by a non-contact tonometer according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] [First embodiment] <Overall configuration of non-contact tonometer> 1 is a side view of a non-contact tonometer 10 according to a first embodiment, which corresponds to an ophthalmic apparatus of the present invention. Of the mutually orthogonal X, Y, and Z directions (three axis directions) in the figure, the X direction is the left-right direction relative to the subject, the Y direction is the up-down direction, and the Z direction is the front-to-back direction (also referred to as the working distance direction) parallel to the front direction approaching the subject (subject's eye E) and the rear direction moving away from the subject.

[0024] As shown in Fig. 1, the non-contact tonometer 10 measures the intraocular pressure of the subject's eye E in a non-contact manner by blowing air (fluid) toward the cornea Ec (see Fig. 2) of the subject's eye E to deform the cornea Ec and detecting the state of deformation. The non-contact tonometer 10 includes a base 11, a face support unit 12, a drive mechanism 13, a measurement head 14 (also referred to as the device main body), a display unit 15, and a control device 16.

[0025] A face support part 12 and a drive mechanism 13 are provided on the base 11 from the subject side toward the examiner side.

[0026] The face support portion 12 includes a chin rest portion 12a for supporting the subject's chin and a forehead rest portion 12b against which the subject's forehead rests, and supports the subject's face when measuring the intraocular pressure of the subject's eye E using the non-contact tonometer 10.

[0027] The drive mechanism 13 holds the measurement head 14 movably in each of the X, Y, and Z directions relative to the base 11. Although not shown, the drive mechanism 13 is configured with a known actuator that moves the measurement head 14 in each of the X, Y, and Z directions, and moves the measurement head 14 in each of the X, Y, and Z directions. The drive mechanism 13 is driven under the control of the control device 16, or driven in response to an operation on an operation unit 38 (see FIG. 7), which will be described later, thereby enabling alignment of the measurement head 14 in the X, Y, and Z directions with respect to the subject's eye E.

[0028] The measurement head 14 corresponds to the ocular characteristic acquisition unit of the present invention, and is held by a drive mechanism 13 so as to be movable in the X, Y, and Z directions relative to the subject's eye E. The measurement head 14 includes multiple types of optical systems for measuring the intraocular pressure of the subject's eye E, a mechanism for blowing air (see FIGS. 2 and 3 described below), and a control device 16. The control device 16 may be provided outside the measurement head 14 (for example, inside the base 11).

[0029] In addition, a convex glass holding portion 35 is formed on the front surface of the measurement head 14 facing the subject (examined eye E) to hold the nozzle 21b (see Figure 2) and the anterior eye window glass 21c (see Figure 3) described below.

[0030] The display unit 15 is attached to the back side of the measurement head 14 facing the examiner. For example, a touch panel monitor is used as this display unit 15. Under the control of the control device 16, the display unit 15 displays an observation image D (see FIG. 2) of the anterior segment of the subject's eye E. The display unit 15 also displays the measurement results of the intraocular pressure value of the subject's eye E. Furthermore, the display unit 15 displays an operation menu screen for performing various operations and a position adjustment screen for adjusting the position of the measurement head 14 in the X, Y, and Z directions (manual alignment). Therefore, the display unit 15 functions as an operation unit 38 (see FIG. 7) that accepts inputs for various operations of the non-contact tonometer 10 by the examiner.

[0031] The control device 16 comprehensively controls the operation of the non-contact tonometer 10. This control device 16 controls various operations, including obtaining and displaying an observation image D of the anterior segment of the subject's eye E, aligning the measurement head 14 in the XYZ directions with respect to the subject's eye E, monitoring the approach of the measurement head 14 with respect to the subject's eye E, emergency stopping of the alignment, blowing air onto the cornea Ec (see FIG. 2 ) of the subject's eye E, emitting target light to the cornea Ec and receiving reflected light from the cornea Ec, and calculating the intraocular pressure value of the subject's eye E.

[0032] [Measuring head configuration] Figure 2 is a schematic top view of multiple types of optical systems in the measurement head 14 viewed from above (Y direction), and Figure 3 is a schematic side view of multiple types of optical systems in the measurement head 14 viewed from the side (X direction).

[0033] As shown in Figures 2 and 3, the measurement head 14 includes an anterior segment observation optical system 21, an XY alignment index projection optical system 22, a fixation target projection optical system 23, an applanation detection optical system 24, a Z alignment index projection optical system 25, a Z alignment detection optical system 26, and a spraying mechanism 34.

[0034] The anterior-segment observation optical system 21 is used for observing the anterior segment of the subject's eye E and for XY-direction alignment of the measurement head 14 with respect to the subject's eye E. An anterior-segment illumination light source 21a (see FIG. 2) is provided in this anterior-segment observation optical system 21. Also, on the optical axis O1 (main optical axis of the non-contact tonometer 10) of the anterior-segment observation optical system 21, there are provided an air-blowing nozzle 21b, an anterior-segment window glass 21c (see FIG. 3) that holds the tip of the nozzle 21b, a chamber window glass 21d, a half mirror 21e, a half mirror 21g, an objective lens 21f, and an image sensor 21i.

[0035] A plurality of anterior-segment illumination light sources 21a are provided around the anterior-segment window glass 21c, and directly illuminate the anterior segment of the subject's eye E.

[0036] The nozzle 21b is connected to a chamber 34a (see FIG. 3) of the spraying mechanism 34, and sprays air onto the anterior segment (cornea Ec) of the eye E to be inspected.

[0037] An image of the anterior segment of the subject's eye E (image light from the anterior segment) passes outside the nozzle 21b, passes through the anterior segment window glass 21c, the glass plate 34b described below, the chamber window glass 21d, the half mirror 21g, and the half mirror 21e, and is formed on the light receiving surface of the imaging element 21i by the objective lens 21f.

[0038] The imaging element 21i is, for example, a CCD (Charge Coupled Device) type or CMOS (Complementary Metal Oxide Semiconductor) type image sensor. The imaging element 21i captures an image of the anterior segment incident on its light receiving surface to generate an imaging signal, and outputs the imaging signal to the control device 16. As a result, under the control of the control device 16, an observation image D of the anterior segment of the subject's eye E based on the imaging signal output from the imaging element 21i is displayed on the display unit 15.

[0039] The anterior-segment observation optical system 21 also guides the XY alignment index light, which is projected onto the subject's eye E by the XY alignment index projection optical system 22 (described later), reflected by the cornea Ec to the light-receiving surface of the image sensor 21i. This reflected light passes through the nozzle 21b, the chamber window glass 21d, the half mirror 21g, and the half mirror 21e, and is imaged on the light-receiving surface of the image sensor 21i by the objective lens 21f. As a result, an XY spot 62 (bright spot image, see FIG. 13) is formed on the light-receiving surface of the image sensor 21i at a position corresponding to the positional relationship (relative position) between the measurement head 14 and the cornea Ec in the X and Y directions. Therefore, the anterior-segment observation optical system 21 and the XY alignment index projection optical system 22 function as part of the relative position detection unit of the present invention.

[0040] The image sensor 21i captures an image of the XY spot 62 formed on its light receiving surface and outputs an image signal of the XY spot 62 to the control device 16. As a result, under the control of the control device 16, the observed image D of the anterior segment and the XY spot 62 are superimposed and displayed on the display unit 15. Note that an alignment assistance mark is also displayed on the display unit 15.

[0041] The XY alignment index projection optical system 22 projects XY alignment index light from the front onto the cornea Ec of the subject's eye E. This XY alignment index light is used for XY alignment of the measurement head 14 with respect to the anterior segment of the subject's eye E. The XY alignment index light is also used to measure the intraocular pressure value of the subject's eye E. Hereinafter, the reflected light of the XY alignment index light by the cornea Ec will be simply abbreviated as "XY index reflected light."

[0042] The XY alignment target projection optical system 22 includes an XY alignment light source 22a, a condenser lens 22b, an aperture stop 22c, a pinhole plate 22d, a dichroic mirror 22e, and a collimator lens 22f (see FIG. 3). The XY alignment target projection optical system 22 shares the half mirror 21e with the anterior eye observation optical system 21.

[0043] XY alignment light source 22a emits infrared light. Collimator lens 22f is arranged on the optical path of XY alignment index projection optical system 22 so that its focal point coincides with pinhole plate 22d. In this XY alignment index projection optical system 22, the infrared light emitted from XY alignment light source 22a is focused by condenser lens 22b, passes through aperture stop 22c, and is directed to the hole in pinhole plate 22d.

[0044] The infrared light that passes through the hole in the pinhole plate 22d is reflected by the dichroic mirror 22e and guided to the collimator lens 22f, where it is collimated and then emitted from the collimator lens 22f to the half mirror 21e. After being reflected by the half mirror 21e, this collimated infrared light travels along the optical axis O1 of the anterior-segment observation optical system 21. As a result, the collimated infrared light passes through the half mirror 21g and the chamber window glass 21d, and then passes through the inside of the nozzle 21b, and is incident on the subject's eye E as XY alignment index light.

[0045] Although not shown, the XY alignment index light incident on the subject's eye E is reflected on the surface of the cornea Ec to form an XY spot 62 (see FIG. 13). The aperture stop 22c is provided at a position conjugate with the corneal apex Ep of the cornea Ec with respect to the collimator lens 22f.

[0046] The fixation target projection optical system 23 projects a fixation target onto the subject's eye E. The fixation target projection optical system 23 has a fixation target light source 23a and a pinhole plate 23b (see FIG. 3). The fixation target projection optical system 23 also shares a dichroic mirror 22e and a collimator lens 22f with the XY alignment target projection optical system 22, and also shares a half mirror 21e with the anterior eye observation optical system 21.

[0047] The fixation target light source 23a emits visible light as fixation target light. This fixation target light is guided to the hole in the pinhole plate 23b, passes through the hole in the pinhole plate 23b and the dichroic mirror 22e, and is then emitted to the collimator lens 22f. The fixation target light is then converted into approximately parallel light by the collimator lens 22f and emitted toward the half mirror 21e. After being reflected by the half mirror 21e, the light travels along the optical axis O1 of the anterior eye observation optical system 21. After passing through the half mirror 21g and the chamber window glass 21d, the fixation target light passes through the inside of the nozzle 21b and reaches the subject's eye E. By having the subject gaze at this fixation target as a fixation target, the subject's line of sight can be fixed.

[0048] The applanation detection optical system 24 (see FIG. 3) receives the XY index reflected light and outputs a detection signal (also called an applanation signal or a corneal deformation signal) indicating the amount of light of the XY index reflected light. The applanation detection optical system 24 has a lens 24a, a pinhole plate 24b, and a light receiving sensor 24c, and also shares the half mirror 21g with the anterior-segment observation optical system 21.

[0049] When the surface of the cornea Ec is flat, the lens 24a focuses the XY index reflected light onto the opening of the pinhole plate 24b, which is provided at the focal position of the lens 24a.

[0050] The light receiving sensor 24c is, for example, a photodiode that outputs a detection signal corresponding to the amount of light received from the reflected XY index light. The light receiving sensor 24c outputs the detection signal (also called an applanation waveform signal) to the control device 16.

[0051] The XY index reflected light passes through the inside of the nozzle 21b, passes through the chamber window glass 21d, and reaches the half mirror 21g. A part of the XY index reflected light is reflected by the half mirror 21g, passes through the lens 24a, and then enters the pinhole plate 24b.

[0052] When the surface of the cornea Ec is flattened (applanated) by the air blown from the nozzle 21b, the applanation detection optical system 24 allows the entire XY index reflected light that has traveled to the applanation detection optical system 24 to reach the light-receiving sensor 24c through the pinhole plate 24b. When the cornea Ec is in a state other than the flat state, the applanation detection optical system 24 allows the XY index reflected light to reach the light-receiving sensor 24c while partially blocking it with the pinhole plate 24b. Therefore, the signal intensity of the detection signal of the XY index reflected light output from the applanation detection optical system 24 gradually increases as the surface of the cornea Ec changes from a convex state to a flat state, and gradually decreases as the surface changes from a flat state to a concave state.

[0053] The Z-alignment index projection optical system 25 (see FIG. 2) projects Z-alignment index light for Z alignment in the Z-axis direction from an oblique direction onto the cornea Ec. The Z-alignment index projection optical system 25 includes, along an optical axis O2, a Z-alignment light source 25a, a condenser lens 25b, an aperture stop 25c, a pinhole plate 25d, and a collimator lens 25e.

[0054] Z-alignment light source 25a emits infrared light (for example, a wavelength of 860 nm). Aperture stop 25c is provided at a position conjugate with corneal vertex Ep with respect to collimator lens 25e. Collimator lens 25e is positioned so as to focus on the hole in pinhole plate 25d.

[0055] The infrared light emitted from the Z-alignment light source 25a is condensed by the condenser lens 25b, passes through the aperture stop 25c, and travels to the pinhole plate 25d. The infrared light that passes through the hole in the pinhole plate 25d is collimated by the collimator lens 25e, and then enters the subject's eye E as Z-alignment index light. The light is reflected by the cornea Ec to form a bright spot image on the subject's eye E.

[0056] The Z alignment detection optical system 26 receives the Z alignment index light reflected by the cornea Ec (hereinafter referred to as Z index reflected light) and detects the positional relationship in the Z axis direction between the measurement head 14 and the cornea Ec. The Z alignment detection optical system 26 has an imaging lens 26a, a cylindrical lens 26b, and a light receiving sensor 26c along the optical axis O3.

[0057] The cylindrical lens 26b has power in the Y-axis direction. The light receiving sensor 26c is a sensor that can detect the light receiving position of the Z index reflected light on its light receiving surface, and is, for example, a line sensor or a PSD (Position Sensitive Detector).

[0058] The Z index reflected light is focused by the imaging lens 26a and then travels to the cylindrical lens 26b, where it is focused in the Y-axis direction to form a bright spot image on the light receiving sensor 26c.

[0059] The light-receiving sensor 26c is positioned conjugately with the bright spot image formed on the subject's eye E by the Z-alignment index projection optical system 25 with respect to the imaging lens 26a in the XZ plane. Furthermore, the light-receiving sensor 26c is positioned conjugately with the corneal vertex Ep with respect to the imaging lens 26a and the cylindrical lens 26b in the YZ plane. That is, since the light-receiving sensor 26c is conjugate with the aperture stop 25c, even if the cornea Ec shifts in the Y direction, the Z-index reflected light from the surface of the cornea Ec efficiently enters the light-receiving sensor 26c. The light-receiving sensor 26c then outputs a detection signal of the Z-index reflected light collected by the cylindrical lens 26b (hereinafter referred to as a Z-detection signal) to the control device 16. This Z-detection signal indicates the relative position of the subject's eye E in the Z direction with respect to the measurement head 14. The Z-alignment index projection optical system 25 and the Z-alignment detection optical system 26 correspond to a part of the relative position detection unit of the present invention.

[0060] The spray mechanism 34 (see FIG. 3) has a chamber 34a, a cylinder 34d, a communication pipe 34e, a piston 34f, and a solenoid 34g.

[0061] Nozzle 21b is attached to chamber 34a via transparent glass plate 34b. Chamber window glass 21d is provided in chamber 34a at a position facing nozzle 21b. Pressure sensor 34c is also provided in chamber 34a. Pressure sensor 34c outputs a pressure detection signal indicating the pressure inside chamber 34a (internal pressure) to control device 16.

[0062] Cylinder 34d is connected to chamber 34a via a communication pipe 34e. This allows the interior of cylinder 34d to communicate with the interior of chamber 34a via communication pipe 34e. A piston 34f is movably provided inside cylinder 34d. The cylinder 34d and piston 34f form an air compression chamber.

[0063] The solenoid 34g is a known solenoid actuator that moves a piston 34f in a cylinder 34d. The solenoid 34g moves the piston 34f under the control of the control device 16, compressing the air in the cylinder 34d. As a result, air is blown from the nozzle 21b toward the cornea Ec of the subject's eye E through the communicating tube 34e and the chamber 34a.

[0064] In the blowing mechanism 34, the pressure sensor 34c detects the internal pressure of the chamber 34a, thereby making it possible to obtain the pressure of the air blown from the nozzle 21b onto the cornea Ec.

[0065] [Capacitive sensor] Fig. 4 is a perspective view of the measurement head 14 as seen from the subject side. Fig. 5 is an enlarged front view of the electrode 36a of the capacitance sensor 36 in Fig. 4. Note that the symbol AX in the figure indicates the central axis of the nozzle 21b parallel to the Z direction, and the symbol HL in the figure is a parallel line that is a straight line parallel to the X direction.

[0066] As shown in Figures 4 and 5, the front side of the measurement head 14 facing the subject is provided with a convex glass holding portion 35 that holds the anterior eye window glass 21c, and a capacitance sensor 36 that corresponds to the non-contact sensor of the present invention.

[0067] The capacitance sensor 36 detects the approach of the nozzle 21b to the subject's face (including the subject's eye E) under the control of the control device 16 described below. The capacitance sensor 36 is, for example, a self-capacitance type, and has an electrode 36a and a detection circuit 36b.

[0068] The electrode 36a is provided on the glass holder 35 and forms a pseudo-capacitor between itself and the face of the subject. When viewed from the tip of the nozzle 21b, the electrode 36a is formed in a region below the parallel line HL within the annular region surrounding the nozzle 21b, i.e., in a substantially semi-annular shape. Here, "formed in a region below the parallel line HL" includes both cases where the electrode 36a is formed in the entire region below the parallel line HL as shown in Figures 4 and 5, and cases where the electrode 36a is formed in a portion of the region below the parallel line HL.

[0069] The detection circuit 36b is provided, for example, inside (or outside) the measurement head 14 and is connected to the electrode 36a via wiring 36c. This detection circuit 36b detects the capacitance generated by the pseudo capacitor and outputs the detected value to the control device 16. The capacitance of the pseudo capacitor increases as the distance between the electrode 36a and the subject's face decreases, and conversely, the capacitance of the pseudo capacitor decreases as the distance between the electrode 36a and the subject's face increases. Therefore, the distance between the electrode 36a (nozzle 21b) and the subject's face can be detected based on the capacitance detected by the detection circuit 36b. As a result, the approach of the nozzle 21b to the subject's face can be detected by the capacitance sensor 36.

[0070] Fig. 6 is an explanatory diagram for explaining the directivity of the capacitance sensor 36. Note that the symbol RD in the figure indicates the detection range of the capacitance sensor 36. Furthermore, the detection range RD shown in Fig. 6 is an example, and the range can be changed as appropriate.

[0071] 6, by forming the electrode 36a in a substantially semi-annular shape, the detection range RD of the capacitance sensor 36 is limited above the central axis AX when the nozzle 21b and the glass holding part 35 are viewed from any one side in the X direction. As a result, the capacitance sensor 36 has directivity toward the front side of the nozzle 21b, but when the nozzle 21b is viewed from any one side in the X direction, the directivity above the central axis AX is weaker than that below the central axis AX.

[0072] By weakening the directivity of the capacitance sensor 36 above the central axis AX in this manner, even when the nozzle 21b is brought within a predetermined distance of the subject's eye E, a sufficient distance is ensured between the electrode 36a and the subject's forehead. Therefore, even when the subject's forehead protrudes (when the subject has a deeply carved face), the capacitance sensor 36 is prevented from erroneously detecting the examiner's forehead. Furthermore, even when the examiner is performing an eyelid-opening operation to open the subject's eyelids, a sufficient distance is ensured between the electrode 36a and the examiner's finger, preventing the capacitance sensor 36 from erroneously detecting the examiner's finger.

[0073] [Control device] 7 is a functional block diagram of the control device 16. As shown in FIG. 7, the control device 16 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 devices (SPLD), complex programmable logic devices (CPLD), and field programmable gate arrays (FPGA)). The various functions of the control device 16 may be realized by a single processor or by multiple processors of the same or different types.

[0074] The control device 16 is connected to the drive mechanism 13, the display unit 15, the various optical systems 21 to 26, and the spray mechanism 34, as well as an operation unit 38.

[0075] As described above, the display surface of the touch panel display unit 15 or the like is used as the operation unit 38. This operation unit 38 accepts inputs for various operations of the non-contact tonometer 10, including turning the power of the non-contact tonometer 10 on and off and starting the alignment of the measurement head 14. Note that the operation unit 38 may be a known operation device such as an operation lever or operation keys.

[0076] The control device 16 executes a control program (not shown) to function as an observation control unit 40, a fixation control unit 42, an alignment control unit 44, a spray control unit 46, a measurement control unit 48, and an intraocular pressure value calculation unit 50. Note that what is described as a "unit" of the control device 16 may also be a "circuit," a "device," or a "equipment." In other words, what is described as a "unit" may be composed of firmware, software, hardware, or a combination of these.

[0077] The observation control unit 40 operates, for example, when an operation to turn on the power of the non-contact tonometer 10 is input via the operation unit 38. The observation control unit 40 controls the anterior-segment observation optical system 21 to turn on the anterior-segment illumination light source 21a, and to capture an observation image D (moving image) of the anterior segment of the subject's eye E using the image sensor 21i and output an image signal. The observation control unit 40 also displays the observation image D on the display unit 15 based on the image signal output from the image sensor 21i.

[0078] The fixation control unit 42 operates, for example, in response to turning on the power of the non-contact tonometer 10. The fixation control unit 42 controls the fixation target projection optical system 23 to turn on the fixation target light source 23a, thereby projecting a light beam of the fixation target onto the subject's eye E and fixing the subject's line of sight.

[0079] The alignment control unit 44, which will be described in detail later, drives the drive mechanism 13 in response to an alignment start operation of the measurement head 14 to align the measurement head 14 with the subject's eye E. Note that alignment of the measurement head 14 includes auto-alignment, in which alignment is performed automatically, and manual alignment, in which alignment is performed in response to a manual operation, but auto-alignment will be described here as an example.

[0080] Furthermore, as will be described in more detail below, the alignment control unit 44 activates the capacitance sensor 36 if there is a risk that the nozzle 21b will come close to the subject's face while the fine Z alignment in the auto alignment is being performed, and stops the alignment if the nozzle 21b is close to the subject's face based on the detection result of this capacitance sensor 36.

[0081] The spray control unit 46 is activated, for example, when auto-alignment of the measurement head 14 with respect to the subject's eye E is completed. The spray control unit 46 drives the solenoid 34g of the spray mechanism 34 to move the piston 34f within the cylinder 34d. This causes the piston 34f to compress the air within the chamber 34a, and the air is sprayed onto the cornea Ec from the nozzle 21b.

[0082] The measurement control unit 48 operates in accordance with the operation of the spray control unit 46. At least while air is being sprayed onto the cornea Ec from the nozzle 21b, the measurement control unit 48 controls the XY alignment target projection optical system 22 and the applanation detection optical system 24 to turn on the XY alignment light source 22a and receive the XY target reflected light with the light-receiving sensor 24c. As a result, while air is being sprayed onto the cornea Ec from the nozzle 21b, the XY alignment target light is continuously projected onto the cornea Ec from the XY alignment target projection optical system 22. At the same time, the light-receiving sensor 24c continuously receives the XY target reflected light and continuously outputs a detection signal of this XY target reflected light to the intraocular pressure value calculation unit 50.

[0083] The intraocular pressure value calculation unit 50 operates in response to input of a detection signal of the XY index reflected light from the light-receiving sensor 24c. The intraocular pressure value calculation unit 50 analyzes the peak position of the applanation waveform based on the detection signal of the XY index reflected light using a known method. Next, the intraocular pressure value calculation unit 50 calculates the intraocular pressure value of the subject's eye E using a known method based on the peak position of the applanation waveform, the signal intensity of the applanation waveform corresponding to this peak position, and the detection result of the pressure sensor 34c. The intraocular pressure value calculation unit 50 then stores the calculation result of the intraocular pressure value of the subject's eye E in a memory unit (not shown) as the measurement result of the intraocular pressure value and displays it on the display unit 15.

[0084] [Alignment control unit] Fig. 8 is a functional block diagram of the alignment control unit 44 in Fig. 7. As shown in Fig. 8, the alignment control unit 44 controls the auto-alignment of the measuring head 14. This auto-alignment includes simple coarse alignment and precise fine alignment (also called precision alignment).

[0085] The coarse alignment includes coarse XY alignment in the X and Y directions and coarse Z alignment in the Z direction. The fine alignment includes fine XY alignment in the X and Y directions and fine Z alignment in the Z direction. Therefore, the alignment control unit 44 functions as a coarse XY alignment control unit 52, a coarse Z alignment control unit 54, a fine Z alignment control unit 56, and a fine XY alignment control unit 58. The alignment control unit 44 also functions as a monitoring control unit 60 during the execution of fine Z alignment.

[0086] (coarse XY alignment) The coarse XY alignment is a simple alignment in the X and Y directions, and is first performed in response to an alignment start operation. As described above, the XY alignment index light passes through the inside of the nozzle 21b and is irradiated onto the cornea Ec, and the XY index reflected light by the cornea Ec passes through the inside of the nozzle 21b and is imaged on the light receiving surface of the image sensor 21i. Therefore, when the alignment state of the subject's eye E in the X and Y directions is significantly deviated, for example, in a standby state before the start of auto-alignment (hereinafter referred to as the standby state), the XY index reflected light is vignetted by the nozzle 21b, and an XY spot 62 (see FIG. 13) is not formed on the light receiving surface of the image sensor 21i.

[0087] Therefore, in the coarse XY alignment, the XY direction position of the approximate center of the pupil of the subject's eye E is aligned on the optical axis O1 based on the observation image D of the anterior segment of the subject's eye E acquired by the anterior segment observation optical system 21.

[0088] 9 is an explanatory diagram for explaining the execution of coarse XY alignment by the coarse XY alignment control unit 52. As shown in Fig. 9, in the standby state, the anterior eye observation optical system 21 continuously acquires an observation image D and continuously outputs the observation image D to the display unit 15. As a result, the observation image D is displayed as a moving image on the display unit 15. When the examiner performs a designation operation to designate the center of the pupil of the subject's eye E on the screen of the display unit 15 as an alignment start operation, the coarse XY alignment control unit 52 is activated.

[0089] The coarse XY alignment control unit 52 performs coarse XY alignment by driving the drive mechanism 13 to move the measurement head 14 in the X and Y directions based on a designated position designated by the examiner on the screen of the display unit 15 so that the designated position moves to the center position of the image sensor 21i. This simply aligns the XY direction position of the approximate center of the pupil of the subject's eye E on the optical axis O1, preventing the XY target reflected light from being vignetted by the nozzle 21b. Note that the XY direction positions of the pupil center of the subject's eye E and the corneal apex Ep do not necessarily coincide, so fine XY alignment using the XY spot 62, which will be described later, is required.

[0090] (coarse Z alignment) FIG. 10 is an explanatory diagram for explaining coarse Z alignment. In the figure, operating position P0 indicates the appropriate Z-direction position of the corneal apex Ep of the subject's eye E during intraocular pressure measurement. The working distance WD indicates the Z-direction distance between the tip of the nozzle 21b and operating position P0. The average corneal position Q0 indicates the average Z-direction position of the corneal apex Ep in the standby state described above. Because the Z-direction position of the corneal apex Ep varies by ±10 mm due to individual differences, the Z-direction position of the corneal apex Ep in the standby state varies between an anterior corneal position Q1 and a posterior corneal position Q2.

[0091] The standby distance SD indicates the distance in the Z direction between the tip of the nozzle 21b and the average corneal position Q0 in the standby state described above. The Z detection range ZR indicates the positional range of the cornea Ec in the Z direction where the Z alignment detection optical system 26 can receive the Z target reflected light.

[0092] 10, the working distance WD is, for example, 11 mm, the Z detection range ZR is, for example, the working position P0±5 mm, and the standby distance SD is, for example, 20 mm. In coarse Z alignment and fine Z alignment, the measurement head 14 is relatively moved in the Z direction so that the corneal apex Ep ultimately moves to the working position P0. However, in the standby state, the Z-direction distance from the working position P0 to the corneal apex Ep varies between 10 mm and 30 mm depending on the individual. Therefore, in the standby state, for subjects for whom this Z-direction distance is short, the Z alignment detection optical system 26 can receive the Z index reflected light, but for most subjects, the Z alignment detection optical system 26 cannot receive the Z index reflected light.

[0093] Therefore, in coarse Z alignment, the measurement head 14 is moved forward in the Z direction (toward the test eye E) so that the Z index reflected light is detected by the Z alignment detection optical system 26, i.e., so that the cornea Ec is included within the Z detection range ZR.

[0094] Specifically, when the coarse XY alignment is completed, the coarse Z alignment control unit 54 starts coarse alignment, which drives the drive mechanism 13 to move the measurement head 14 forward in the Z direction. When the cornea Ec is at the mean corneal position Q0, the Z index reflected light can be detected by the Z alignment detection optical system 26 by advancing the measurement head 14 forward 10 mm in the Z direction through coarse Z alignment. Also, even when the cornea Ec is at the posterior corneal position Q2, the Z index reflected light can be detected by the Z alignment detection optical system 26 by advancing the measurement head 14 forward 20 mm in the Z direction through coarse Z alignment.

[0095] In this way, coarse Z alignment enables the Z alignment detection optical system 26 to detect the Z index reflected light, which makes it possible to perform fine Z alignment based on the Z detection signal output from the Z alignment detection optical system 26. Therefore, when the Z index reflected light is detected by the Z alignment detection optical system 26, the coarse Z alignment control unit 54 ends the coarse alignment.

[0096] (fine Z alignment) Fig. 11 is an explanatory diagram showing the light beams of the Z alignment index light and the Z index reflected light for each Z direction position of the cornea Ec during fine Z alignment. Fig. 12 is an explanatory diagram showing the incident position of the Z index reflected light on the light receiving sensor 26c for each Z direction position of the cornea Ec and the signal intensity of the Z detection signal output from the light receiving sensor 26c.

[0097] 11, symbol L0 indicates the beam of Z alignment index light and reflected Z index light when the corneal apex Ep is at the operating position P0. Symbol L1 indicates the beam of Z alignment index light and reflected Z index light when the corneal apex Ep is at a near position P1, which is further forward in the Z direction than the operating position P0, within the Z detection range ZR. Symbol L2 indicates the beam of Z alignment index light and reflected Z index light when the corneal apex Ep is at a far position P2, which is further backward in the Z direction than the operating position P0, within the Z detection range ZR.

[0098] Also, in Figure 12, symbol Sig0 indicates the Z detection signal when the corneal apex Ep is at the operating position P0, symbol Sig1 indicates the Z detection signal when the corneal apex Ep is at the near position P1, and symbol Sig2 indicates the Z detection signal when the corneal apex Ep is at the far position P2.

[0099] 11 and 12, fine Z alignment adjusts the Z-direction position of the corneal apex Ep to the operating position P0 based on the Z detection signal output from the Z alignment detection optical system 26. When the corneal apex Ep is located at the operating position P0, that is, when an appropriate working distance WD is maintained, the Z index reflected light is incident on approximately the center of the light receiving sensor 26c. In this case, the signal strength of the Z detection signal also becomes strong.

[0100] On the other hand, when the corneal apex Ep is shifted forward in the Z direction (toward the near position P1) from the operating position P0, the incident position of the Z index reflected light to the light receiving sensor 26c is shifted toward the + direction in Fig. 12, and conversely, when the corneal apex Ep is shifted backward in the Z direction (toward the far position P2) from the operating position P0, the incident position of the Z index reflected light to the light receiving sensor 26c is shifted toward the - direction in Fig. 12. In this case, the imaging condition of the Z index reflected light on the light receiving sensor 26c deteriorates, and the signal strength of the Z detection signal weakens.

[0101] Therefore, in fine Z alignment, the Z direction position of the measuring head 14 is finely adjusted based on the detection results of the Z detection signal output from the Z alignment detection optical system 26, i.e., the incident position of the Z index reflected light relative to the light receiving sensor 26c and the signal strength of the Z detection signal, etc.

[0102] Specifically, the fine Z alignment control unit 56 operates when coarse Z alignment is completed, that is, when a Z detection signal is output from the Z alignment detection optical system 26. Based on the detection result of the Z detection signal by the Z alignment detection optical system 26, the fine Z alignment control unit 56 drives the drive mechanism 13 to perform fine Z alignment of the measurement head 14 so that the incident position of the Z detection signal on the light-receiving sensor 26c moves to a predetermined position (center position) of the light-receiving sensor 26c. This adjusts the position of the corneal apex Ep to the operating position P0.

[0103] Furthermore, during fine Z alignment, the imaging state of the XY spot 62 (see FIG. 13) formed on the light receiving surface of the image sensor 21i of the anterior-segment observation optical system 21 gradually improves, so that the XY spot 62 can be detected from the observation image D output from the anterior-segment observation optical system 21. This makes it possible to perform fine XY alignment based on the XY spot 62.

[0104] (fine XY alignment) Fig. 13 is an explanatory diagram for explaining fine XY alignment. As shown in Fig. 13 and the above-mentioned Fig. 8, the fine XY alignment uses an XY spot 62 in the observation image D output from the anterior eye observation optical system 21 to adjust the XY direction position of the corneal apex Ep to be on the optical axis O1 (the center of the image sensor 21i).

[0105] Specifically, each time an observation image D is output from the anterior-segment observation optical system 21 while fine Z alignment is being performed, the fine XY alignment control unit 58 determines whether or not the XY spot 62 can be detected from this observation image D. If the fine XY alignment control unit 58 determines that the XY spot 62 has become detectable, it drives the drive mechanism 13 based on the XY spot 62 detected from the observation image D to perform fine XY alignment, i.e., adjusts the XY direction position of the measurement head 14. This adjusts the XY direction position of the corneal apex Ep to be aligned with the optical axis O1.

[0106] [Approach monitoring control] 14 is an explanatory diagram illustrating the execution conditions for detecting the proximity of the subject's face using the capacitance sensor 36 by the monitoring control unit 60. When there is a risk that the nozzle 21b will come into contact with the subject's face during fine Z alignment, the monitoring control unit 60 determines whether the nozzle 21b is approaching the subject's face during fine alignment based on the detected capacitance value output from the capacitance sensor 36, and cancels the fine Z alignment if the nozzle 21b comes into proximity with the subject's face. In this case, if the detection of the proximity of the subject's face using the capacitance sensor 36 is constantly performed during fine Z alignment, there is a risk that the nozzle 21b may be determined to be approaching the subject's face even though there is no risk that the nozzle 21b will come into contact with the subject's face depending on the shape of the subject's face, etc.

[0107] For example, as shown by reference symbol XIVA in Figure 14, even if coarse XY alignment has been performed with high accuracy, the bridge of the subject's nose (or forehead or cheek) may be included in the detection range RD of the capacitance sensor 36 while the measurement head 14 is being moved forward in the Z direction (toward the subject) during fine Z alignment. In this case, even if fine Z alignment is continued, there is no risk of the nozzle 21b coming into contact with the bridge of the nose, but it is determined that the nozzle 21b is approaching the subject's face. For this reason, in this case, it is preferable to stop detecting the approach of the subject's face using the capacitance sensor 36.

[0108] On the other hand, as shown by symbol XIVB in Fig. 14, if there is a large misalignment in the XY directions between the subject's eye E and the optical axis O1 even after the coarse XY alignment, there is a risk that the nozzle 21b will come into contact with the subject's face when fine Z alignment is performed. In this case, it is necessary to detect the approach of the subject's face using the capacitance sensor 36.

[0109] Here, if there is a risk that nozzle 21b will come into contact with the subject's face due to a problem with the coarse XY alignment or the like, the alignment will be misaligned, so the Z index reflected light will not be incident on light receiving sensor 26c of Z alignment detection optical system 26, and a Z detection signal suitable for fine Z alignment will not be output from Z alignment detection optical system 26. Conversely, if there is no problem with the coarse XY alignment and there is no risk that nozzle 21b will come into contact with the subject's face, the Z index reflected light will be incident on light receiving sensor 26c, and a Z detection signal suitable for fine Z alignment will be output from Z alignment detection optical system 26.

[0110] In other words, when the Z alignment detection optical system 26 outputs a Z detection signal suitable for fine Z alignment, the relative positional relationship between the subject's eye E and the measurement head 14 is clear, and the nozzle 21b is unlikely to come into contact with the subject's face. Therefore, as indicated by the reference symbol XIVA, even if the nozzle 21b is close to the subject's nose bridge (forehead or cheek), the position of the subject's eye E (cornea Ec) is known, so there is no risk of the nozzle 21b coming into contact with the subject's eye E, and intraocular pressure measurement is possible.

[0111] Conversely, if the Z alignment detection optical system 26 does not output a Z detection signal suitable for fine Z alignment, it is possible that the alignment of the measurement head 14 with the subject's eye E in the X and Y directions is significantly off, causing the bridge of the nose, cheek, forehead, etc., to be in front of the measurement head 14 instead of the subject's eye E, or that the subject's eyelids are closed. It is also possible that the measurement head 14 is too far away from the subject's eye E in the Z direction or too close. In such cases, the relative positional relationship between the subject's eye E and the measurement head 14 is unclear, and there is a possibility that the nozzle 21b will come into contact with the subject's face, particularly the subject's eye E. Therefore, during fine Z alignment, it is possible to determine whether the nozzle 21b will come into contact with the subject's face based on whether the Z alignment detection optical system 26 outputs a Z detection signal suitable for fine Z alignment.

[0112] Therefore, if the output of the Z detection signal from the Z alignment detection optical system 26 is interrupted during execution of fine Z alignment, or if the Z detection signal is not suitable for fine Z alignment, that is, if the relative positional relationship between the subject's eye E and the measurement head 14 becomes unclear (undetectable), the monitoring control unit 60 performs approach detection of the subject's face using the capacitance sensor 36. As a result, the monitoring control unit 60 determines whether the nozzle 21b is approaching the subject's face. Then, if the nozzle 21b is approaching the subject's face, the monitoring control unit 60 stops the fine Z alignment.

[0113] Returning to FIG. 8, the monitoring control unit 60 functions as a detection control unit 60a, a determination unit 60b, a stop control unit 60c, and a notification control unit 60d.

[0114] During the execution of fine Z alignment, the detection control unit 60a continues the projection of Z alignment index light onto the cornea Ec by the Z alignment index projection optical system 25, and the detection of the Z index reflected light by the Z alignment detection optical system 26 and the output of a Z detection signal.

[0115] During execution of fine Z alignment, the determination unit 60b does not operate while a Z detection signal is being output from the Z alignment detection optical system 26, but operates when the output of the Z detection signal from the Z alignment detection optical system 26 is interrupted or when the Z detection signal is not suitable for fine Z alignment, and starts detecting the approach of the subject's face using the capacitance sensor 36. As a result, detected capacitance values ​​from the capacitance sensor 36 are sequentially input to the determination unit 60b. Note that the capacitance sensor 36 may operate only when the determination unit 60b makes a determination, or the capacitance sensor 36 may be constantly operating, with the determination unit 60b acquiring a detection value from the capacitance sensor 36 only when the determination unit 60b makes a determination.

[0116] Each time the determination unit 60b acquires a new capacitance detection value from the capacitance sensor 36, the determination unit 60b continuously determines whether the detection value is greater than a predetermined threshold. This threshold is determined, for example, based on the capacitance detection value when the distance between the nozzle 21b and the subject's face (hereinafter referred to as the face distance) is 5 mm, i.e., the capacitance detection value corresponding to the face distance at which the nozzle 21b comes into contact with the eyelashes on the face. Therefore, it can be said that the determination unit 60b continuously determines whether the face distance has become less than the predetermined threshold each time the determination unit 60b acquires a new capacitance detection value from the capacitance sensor 36.

[0117] The stop control unit 60c does not operate while a Z detection signal is being output from the Z alignment detection optical system 26 or while the determination unit 60b determines that the result is negative. However, it operates when the determination unit 60b determines that the detected capacitance value is greater than the threshold (the face distance is less than the threshold), i.e., when it determines that the nozzle 21b is close to the subject's face. The stop control unit 60c drives the drive mechanism 13 to stop the fine Z alignment (auto-alignment), and then retracts the measurement head 14 (nozzle 21b) away from the subject's eye E. In this case, the stop control unit 60c functions as a danger avoidance operation control unit of the present invention, and stops the auto-alignment (stops the movement of the measurement head 14) and retracts the measurement head 14 as a danger avoidance operation. Note that only one of stopping the movement of the measurement head 14 and retracting it may be performed.

[0118] 15 is an explanatory diagram showing an example of the notification of warning information 64 by the notification control unit 60d. As shown in FIG. 15 and the above-described FIG. 8, the notification control unit 60d functions as the notification unit of the present invention together with the display unit 15. When the determination unit 60b makes a proximity determination, the notification control unit 60d causes the display unit 15 to display warning information 64 indicating that the nozzle 21b is close to the subject's face. Instead of or in addition to displaying the warning information 64 on the display unit 15, the notification control unit 60d may output the warning information 64 as sound from a speaker (not shown) or vibrate a part of the non-contact tonometer 10.

[0119] [Operation of the non-contact tonometer of the first embodiment] 16 is a flowchart showing the flow of the intraocular pressure measurement process of the subject's eye E by the non-contact tonometer 10 of the first embodiment having the above-described configuration related to the control method for an ophthalmologic apparatus of the present invention. As shown in FIG. 16, when the power of the non-contact tonometer 10 is turned on, each optical system of the non-contact tonometer 10 is activated, and an observation image D of the anterior segment of the subject's eye E acquired by the anterior segment observation optical system 21 is displayed (moving image display) on the display unit 15. Then, when the subject's face is supported by the face support unit 12, the examiner operates the operation unit 38 to adjust the face position (adjust the height of the chin rest 12a, etc.) so that the observation image D is displayed on the display unit 15 (NO in steps S1 and S2).

[0120] When the observation image D is displayed on the display unit 15, the examiner performs a designation operation to designate the center of the pupil of the subject's eye E on the screen of the display unit 15 (in the observation image D) as an alignment start operation, as shown in Fig. 9 described above. In response to this operation, the coarse XY alignment control unit 52 drives the drive mechanism 13 to perform coarse XY alignment of the measurement head 14 so that the designated position designated by the examiner on the screen of the display unit 15 moves to the center position of the image sensor 21i (step S3).

[0121] When the coarse XY alignment is completed, the coarse Z alignment control unit 54 drives the drive mechanism 13 to start coarse Z alignment of the measurement head 14 (step S4), as shown in Fig. 10. This coarse Z alignment continues until a Z detection signal is output from the Z alignment detection optical system 26. If a Z detection signal is not output from the Z alignment detection optical system 26 after a predetermined time has passed or after a predetermined amount of movement, the processing from step S2 is repeated (NO in step S5).

[0122] When the cornea Ec moves into the Z detection range ZR due to the coarse Z alignment, the Z alignment detection optical system 26 detects the Z index reflected light, and outputs a Z detection signal (YES in step S5).

[0123] When a Z detection signal is output from the Z alignment detection optical system 26, the fine Z alignment control unit 56 drives the drive mechanism 13 to start fine Z alignment of the measurement head 14 based on the detection result of the Z detection signal by the Z alignment detection optical system 26, as shown in Figures 11 and 12 (step S6, which corresponds to the alignment control step of the present invention).

[0124] In addition, in response to the start of fine Z alignment, the monitoring control unit 60 shown in FIG. 8 is activated. First, the detection control unit 60a continues the operation of the Z alignment target projection optical system 25 and the Z alignment detection optical system 26 even during execution of fine Z alignment. This causes the Z alignment detection optical system 26 to continue outputting a Z detection signal (step S7, corresponding to the detection control step of the present invention). At this time, since the approach detection of the subject's face is not performed using the capacitance sensor 36, as shown by symbol XIVA in FIG. 14, it is determined that the nozzle 21b is approaching the subject's face even though there is no risk of the nozzle 21b coming into contact with the subject's face, and this prevents the fine Z alignment from being stopped.

[0125] When the output of the Z detection signal from the fine Z alignment and Z alignment detection optical system 26 continues, the imaging state of the XY spot 62 formed on the light receiving surface of the image sensor 21i gradually improves (YES in step S8). Every time an observation image D is output from the anterior eye observation optical system 21, the fine XY alignment control unit 58 determines whether the XY spot 62 can be detected from this observation image D (NO in step S9).

[0126] Then, when the XY spot 62 can be detected from the observation image D (YES in step S9), the fine XY alignment control unit 58 drives the drive mechanism 13 based on the XY spot 62 detected from the observation image D, as shown in FIG. 13, to start fine XY alignment of the measuring head 14. This performs fine XYZ alignment of the measuring head 14 (step S10). Thereafter, the processes of steps S8 to S11 are repeatedly executed until fine XYZ alignment is completed (NO in step S11).

[0127] When the fine XYZ alignment is completed without interruption in the output of the Z detection signal from the Z alignment detection optical system 26 (YES in step S11), the spray control unit 46 drives the spray mechanism 34 to spray air from the nozzle 21b onto the cornea Ec of the subject's eye E (step S12). At the same time, the measurement control unit 48 controls the XY alignment target projection optical system 22 and the applanation detection optical system 24 to project the XY alignment target light onto the cornea Ec, receive the XY target reflected light by the light receiving sensor 24c, and output a detection signal of the XY target reflected light from the light receiving sensor 24c to the intraocular pressure value calculation unit 50.

[0128] Then, the intraocular pressure value calculation unit 50 calculates the intraocular pressure value of the subject's eye E based on the detection signal of the XY index reflected light input from the light-receiving sensor 24c. This intraocular pressure value is stored in a storage unit (not shown) and is displayed on the display unit 15 (step S13).

[0129] On the other hand, if the relative positional relationship between the test eye E and the measurement head 14 becomes unclear (undetectable) due to reasons such as the output of the Z detection signal from the Z alignment detection optical system 26 being interrupted during fine Z alignment (NO in step S8), the judgment unit 60b sequentially acquires the capacitance detection values ​​from the capacitance sensor 36 (step S14).

[0130] Then, every time the determination unit 60b acquires a new capacitance detection value from the capacitance sensor 36, the determination unit 60b performs a proximity determination to determine whether the detection value is greater than a predetermined threshold, i.e., whether the face distance is less than a predetermined threshold (step S15, which corresponds to the determination step of the present invention). If the determination unit 60b determines that the detection value is not greater than a predetermined threshold, i.e., if the determination unit 60b determines that the nozzle 21b is not close to the subject's face, the processing from step S8 onwards continues (NO in step S16).

[0131] Conversely, if the determination unit 60b determines that the nozzle 21b is close to the subject's face (YES in step S16), the stop control unit 60c drives the drive mechanism 13 to stop the fine Z alignment (and also the fine XY alignment) (step S17, which corresponds to the danger avoidance operation step of the present invention), thereby preventing the nozzle 21b from colliding with the subject's face.

[0132] At the same time, the notification control unit 60d displays warning information 64 on the display unit 15 as shown in Fig. 15 (step S18). This notifies the examiner that the nozzle 21b has approached the subject's face. Then, the stop control unit 60c drives the drive mechanism 13 to retract the measurement head 14 away from the subject's eye E (step S19).

[0133] [Effects of the first embodiment] As described above, in the first embodiment, when the relative positional relationship between the subject's eye E and the measurement head 14 becomes unclear during fine Z alignment, the capacitance sensor 36 is used to detect the approach of the subject's face. Otherwise, the approach detection can be omitted. Therefore, when there is a possibility that the nozzle 21b may come into contact with the subject's face, the approach detection is performed, thereby preventing the nozzle 21b from coming into contact with the subject's face during fine Z alignment. Furthermore, when there is no possibility that the nozzle 21b may come into contact with the subject's face, the approach detection is omitted, thereby preventing the nozzle 21b from being determined to be close to the subject's face even when there is no risk of the nozzle 21b coming into contact with the subject's face. This allows fine Z alignment to be performed simply and quickly. As a result, fine Z alignment can be performed simply and quickly while preventing the nozzle 21b from coming into contact with the subject's face during fine Z alignment.

[0134] [Second embodiment] 17 is a flowchart showing the flow of the intraocular pressure measurement process of the subject's eye E using the non-contact tonometer 10 of the second embodiment. Note that the configuration of the non-contact tonometer 10 of the second embodiment is basically the same as that of the first embodiment, and therefore, components that are the same in function or configuration as those of the first embodiment are assigned the same reference numerals and their description will be omitted.

[0135] In the first embodiment, if the output of the Z detection signal from the Z alignment detection optical system 26 is interrupted during fine Z alignment as shown in step S8 in Fig. 16, the determination unit 60b immediately starts acquiring the capacitance detection value from the capacitance sensor 36 (step S14) and making a determination (step S15). In this case, even if the output of the Z detection signal is interrupted due to blinking of the subject's eye E or a momentary movement of the line of sight, detection of the approach of the subject's face using the capacitance sensor 36 will start.

[0136] 17, in the second embodiment, if a state in which the output of the Z detection signal from the Z alignment detection optical system 26 is interrupted continues for a predetermined period of time (YES in step S8A), the processing from step S14 onwards is started. This prevents unnecessary approach detection from being started due to blinking or a momentary movement of the line of sight of the subject's eye E as described above, making it possible to perform alignment more simply and in a shorter time than in the first embodiment.

[0137] [Third embodiment] Next, a non-contact tonometer 10 according to a third embodiment of the present invention will be described. In the non-contact tonometers 10 according to the above-described embodiments, the determination unit 60b acquires the detection value from the capacitance sensor 36 and performs a proximity determination only when the output of the Z detection signal from the Z alignment detection optical system 26 is interrupted during fine Z alignment (when the relative positional relationship between the subject's eye E and the measurement head 14 becomes undetectable). In contrast, in the non-contact tonometer 10 according to the third embodiment, the determination unit 60b repeatedly acquires the detection value and performs a proximity determination (determines whether the detection value of the capacitance sensor 36 is greater than the threshold value) during fine Z alignment. Therefore, in the non-contact tonometer 10 according to the third embodiment, the determination of whether the Z detection signal is being output from the Z alignment detection optical system 26 and the proximity determination are repeatedly performed during fine Z alignment.

[0138] The non-contact tonometer 10 of the third embodiment has basically the same configuration as the non-contact tonometers 10 of the above-mentioned embodiments, and therefore, parts that are identical in function or configuration to the above-mentioned embodiments will be given the same reference numerals and their description will be omitted.

[0139] 18 is a flowchart showing the flow of the intraocular pressure measurement process of the subject's eye E by the non-contact tonometer 10 of the third embodiment. Note that the processes from step S1 to step S7 in the figure are basically the same as those in the first embodiment shown in FIG. 16, so a detailed description thereof will be omitted here.

[0140] As shown in Figure 18, when fine Z alignment of the measurement head 14 is started (step S6, see Figure 16), the detection control unit 60a continues to operate the Z alignment index projection optical system 25 and the Z alignment detection optical system 26, thereby continuing to output a Z detection signal from the Z alignment detection optical system 26 (step S7).

[0141] At the same time, the determination unit 60b of the third embodiment acquires a capacitance detection value from the capacitance sensor 36 (step S8B) and starts a proximity determination as to whether or not this detection value is greater than a threshold value, that is, whether or not the nozzle 21b has approached the face of the subject (step S8C). As a result, in the third embodiment, the determination unit 60b continuously acquires the detection value and performs proximity determination while fine Z alignment is being performed.

[0142] In the third embodiment, if the output of the Z detection signal from the Z alignment detection optical system 26 continues, fine Z alignment continues regardless of the result of the proximity determination by the determination unit 60b (NO in step S8D). As described above, in the third embodiment, as long as the relative positional relationship between the subject's eye E and the measurement head 14 is clear, there is no risk of the nozzle 21b coming into contact with the subject's face, so fine Z alignment (and fine XY alignment as well) continues. Note that, if the determination unit 60b determines that the nozzle 21b is approaching the subject's face (the detected value of the capacitance is greater than the threshold value) while the output of the Z detection signal from the Z alignment detection optical system 26 continues, the previously described warning information 64 may be issued, or the movement speed of the measurement head 14 may be slowed down.

[0143] Thereafter, if the output of the Z detection signal from the Z alignment detection optical system 26 continues without interruption, the processing from step S9 to step S13 is executed in the same manner as in each of the above-described embodiments shown in Figures 16 and 17.

[0144] On the other hand, when the output of the Z detection signal from the Z alignment detection optical system 26 is interrupted and the determination unit 60b determines that the nozzle 21b is close to the subject's face (the detected capacitance value is greater than the threshold value) (YES in step S8D), the stop control unit 60c in the third embodiment executes the process of step S17 (stopping fine XYZ alignment) as described above. Thereafter, the processes from step S18 onwards are executed as in the first embodiment.

[0145] As described above, in the third embodiment, fine XYZ alignment is stopped only when the relative positional relationship between the subject's eye E and the measuring head 14 cannot be detected and when it is determined that the nozzle 21b is close to the subject's face, and fine XYZ alignment continues in other cases. This prevents the fine XYZ alignment from being stopped even when there is no risk of the nozzle 21b coming into contact with the subject's face, that is, prevents a risk avoidance operation from being performed, thereby achieving the same effect as the first embodiment.

[0146] [Fourth embodiment] 19 is a flowchart showing the flow of the intraocular pressure measurement process of the subject's eye E by the non-contact tonometer 10 of the fourth embodiment. Note that the configuration of the non-contact tonometer 10 of the fourth embodiment is basically the same as that of each of the above embodiments, and therefore, components that are the same in function or configuration as those of each of the above embodiments are assigned the same reference numerals and their description will be omitted.

[0147] 19, the stop control unit 60c of the fourth embodiment determines whether the state in which the output of the Z detection signal from the Z alignment detection optical system 26 has been interrupted continues for a certain period of time or more, as described in the second embodiment (see FIG. 17). Then, if the state in which the output of the Z detection signal has been interrupted continues for a certain period of time (YES in step S8E) and the determination unit 60b determines that the nozzle 21b is close to the face of the subject (YES in step S8F), the stop control unit 60c drives the drive mechanism 13 to stop the fine XYZ alignment (step S17). Thereafter, the processing from step S18 onwards is executed as in each of the above embodiments.

[0148] Furthermore, in the fourth embodiment, even if the output of the Z detection signal is interrupted, if this state does not continue for a certain period of time (NO in step S8E), or while the judgment unit 60b judges that the nozzle 21b is not close to the subject's face (NO in step S8F), the processing from step S9 to step S13 described above is executed.

[0149] As described above, in the fourth embodiment, fine XYZ alignment is stopped only when the relative positional relationship between the subject's eye E and the measurement head 14 becomes undetectable for a certain period of time and it is determined that the nozzle 21b is close to the subject's face, thereby achieving the same effect as that described in the second embodiment above.

[0150] [Fifth embodiment] 20 is a flowchart showing the flow of the intraocular pressure measurement process of the subject's eye E using the non-contact tonometer 10 of the fifth embodiment. Note that the configuration of the non-contact tonometer 10 of the fifth embodiment is basically the same as that of each of the above embodiments, and therefore, components that are the same in function or configuration as those of each of the above embodiments are assigned the same reference numerals and their description will be omitted.

[0151] 20, the stop control unit 60c of the fifth embodiment counts (counts up) the number of times the output of the Z detection signal from the Z alignment detection optical system 26 is interrupted (the number of times the Z detection signal cannot be detected) during execution of fine Z alignment (NO in step S8G, step S8H). Then, when the count number of times the output of the Z detection signal is interrupted reaches a predetermined upper limit (YES in step S8I) and the determination unit 60b determines that the nozzle 21b is close to the face of the subject (YES in step S8J), the stop control unit 60c drives the drive mechanism 13 to stop the fine XYZ alignment (step S17). Thereafter, the processing from step S18 onwards is executed as in each of the above embodiments.

[0152] On the other hand, in the fifth embodiment, the processing from step S9 to step S13 described above is executed until the above-mentioned count number reaches the upper limit number (NO in step S8I) or while the judgment unit 60b judges that the nozzle 21b is not close to the subject's face (NO in step S8J).

[0153] As described above, in the fifth embodiment, fine XYZ alignment is stopped only when the number of times the output of the Z detection signal is interrupted, i.e., the number of times the relative positional relationship between the subject's eye E and the measurement head 14 becomes undetectable, reaches a predetermined upper limit and it is determined that the nozzle 21b is close to the subject's face. This prevents the fine XYZ alignment from being stopped due to the subject's eye E blinking or a momentary movement of the line of sight, i.e., the execution of a risk avoidance operation, as in the second embodiment (fourth embodiment). As a result, the same effects as those described in the second embodiment can be obtained.

[0154] In the second embodiment (see FIG. 17), as described in the fifth embodiment, the processing from step S14 onward may be executed only when the number of times the output of the Z detection signal has been interrupted reaches a predetermined upper limit.

[0155] [Sixth embodiment] 21 is a block diagram of a non-contact tonometer 10 of a sixth embodiment. In the above-described embodiments, automatic alignment (coarse XYZ alignment, fine XYZ alignment) is performed to align the measurement head 14 with the subject's eye E, but the non-contact tonometer 10 of the sixth embodiment performs manual alignment. The non-contact tonometer 10 of the sixth embodiment has basically the same configuration as the non-contact tonometers 10 of the above-described embodiments, except that the operation unit 38 is provided with an operation lever 38a and the control device 16 functions as a mode switching control unit 70. For this reason, components that are the same in function or configuration as those of the above-described embodiments are designated by the same reference numerals, and their description will be omitted.

[0156] The operating lever 38a is an operating member that is operated to move the measuring head 14 in the X, Y, and Z directions during manual alignment. For example, when the operating lever 38a is tilted in the Z direction (front-back direction) or the X axis direction (left-right direction), the alignment control unit 44 drives the drive mechanism 13 to move the measuring head 14 in the Z direction or the X direction. Furthermore, when the operating lever 38a is rotated around its longitudinal axis, the drive mechanism 13 moves the measuring head 14 in the Y direction (up-down direction) depending on the direction of the rotation.

[0157] The mode switching control unit 70 selectively switches the drive mode in which the alignment control unit 44 drives the drive mechanism 13 during manual alignment to either the normal mode or the speed limited mode based on the detected value of the electrostatic quantity obtained from the capacitance sensor 36.

[0158] Specifically, when the detected value of the electrostatic quantity acquired from the capacitance sensor 36 is equal to or less than a predetermined threshold, i.e., when the nozzle 21b is not close to the subject's face, the mode switching control unit 70 switches the drive mode to the normal mode. In this normal mode, the movement speed of the measurement head 14 increases as the tilt angle or rotation angle of the operation lever 38a increases, and conversely, the movement speed of the measurement head 14 decreases as the tilt angle or rotation angle of the operation lever 38a decreases. This allows the measurement head 14 to move at the set maximum speed by tilting or rotating the operation lever 38a to the maximum angle.

[0159] On the other hand, when the detected value of the electrostatic quantity acquired from the capacitance sensor 36 is greater than the threshold value, i.e., when the nozzle 21b is close to the subject's face, the mode switching control unit 70 switches the drive mode to the speed limited mode. The speed limited mode is a mode in which at least the forward movement speed of the measurement head 14 in the Z direction is reduced below the speed corresponding to the tilt angle of the operation lever 38a, and the maximum movement speed is also limited. As a result, even if the operation lever 38a is tilted forward by more than a certain angle, the forward movement speed of the measurement head 14 is limited. Note that the movement speed may be set to the same as in the normal mode until the forward tilt angle of the operation lever 38a reaches a certain angle, and the movement speed may be limited once the tilt angle exceeds the certain angle.

[0160] 22 is a flowchart showing the flow of the intraocular pressure measurement process of the subject's eye E by the non-contact tonometer 10 of the sixth embodiment. As shown in Fig. 22, when manual alignment of the measurement head 14 with respect to the subject's eye E is started (step S22), the mode switching control unit 70 acquires a detection value of capacitance from the capacitance sensor 36 and determines whether or not this detection value exceeds a threshold value, that is, performs proximity determination to determine whether or not the nozzle 21b has approached the subject's face (step S23).

[0161] If the detected capacitance value is equal to or less than the threshold value, the mode switching control unit 70 sets the drive mode of the drive mechanism 13 to the normal mode (NO in step S23, step S24). As a result, the alignment control unit 44 drives the drive mechanism 13 in accordance with the "tilt direction and tilt angle" or "rotation direction and rotation angle" of the operation lever 38a, and moves the measuring head 14 in the X, Y, and Z directions at a speed that corresponds to the tilt angle or rotation angle of the operation lever 38a.

[0162] On the other hand, if the detected capacitance value is greater than the threshold value, the mode switching control unit 70 sets the drive mode of the drive mechanism 13 to the speed limited mode (YES in step S23, step S25). As a result, when at least the operation lever 38a is tilted forward in the Z direction, the alignment control unit 44 limits the movement speed when driving the drive mechanism 13 to move the measuring head 14 forward, i.e., slows it down compared to the normal mode. This makes it difficult for the nozzle 21b to come into contact with the subject's face even when the nozzle 21b is close to the subject's face. In this case, the warning information 64 described above may be issued.

[0163] In addition, when the operating lever 38a is tilted or rotated in a direction other than the forward direction in the speed limited mode, the alignment control unit 44 may drive the drive mechanism 13 to move the measuring head 14 at the same movement speed as in the normal mode.

[0164] Thereafter, the processes from step S22 to step S25 are repeatedly executed until the manual alignment is completed (NO in step S26). Then, when the manual alignment is completed (YES in step S26), the intraocular pressure of the subject's eye E is measured (step S27) and the intraocular pressure measurement result is displayed (step S28), as in each of the above-described embodiments.

[0165] As described above, in the sixth embodiment, when the nozzle 21b is close to the subject's face during manual alignment, the movement speed of the measurement head 14 can be limited at least in the forward direction, making it difficult for the nozzle 21b to come into contact with the subject's face.

[0166] [others] In the above-described embodiments, the monitoring control unit 60 is operated only during fine Z alignment, but the monitoring control unit 60 may also be operated during fine XY alignment. In this case, the detection control unit 60a continues the emission of XY alignment index light by the anterior eye observation optical system 21, the imaging of the XY spot 62, and the output of the imaging signal. Furthermore, when the output of the imaging signal from the anterior eye observation optical system 21 is interrupted, the determination unit 60b detects the approach of the subject's face using the capacitance sensor 36 and performs an approach determination based on this detection result. Note that the operations of the stop control unit 60c and the notification control unit 60d are the same as those of the above-described embodiments.

[0167] In the above-described embodiments, the monitoring and control unit 60 is operated only during fine Z alignment (fine XY alignment). However, for example, some functions of the monitoring and control unit 60 may be used to prevent the nozzle 21b from contacting the subject's face during coarse Z alignment as well. For example, as shown in step S5 of FIG. 16, if a Z detection signal is not output from the Z alignment detection optical system 26 after a certain period of time has elapsed since the start of coarse Z alignment, the determination unit 60b detects the approach of the subject's face using the capacitance sensor 36 and determines the proximity based on the detection result. Then, if the determination unit 60b determines that the nozzle 21b is approaching the subject's face, the stop control unit 60c and the notification control unit 60d are activated. This prevents the nozzle 21b from contacting the subject's face during coarse Z alignment.

[0168] In the above embodiments, automatic alignment has been described as an example of aligning the measurement head 14 with the subject's eye E. However, the present invention can also be applied to manual alignment. In manual alignment, the alignment state of the measurement head 14 with the subject's eye E is displayed on the display unit 15 based on the Z detection signal output from the Z alignment detection optical system 26 and the XY spot 62 detected from the observation image D. The examiner then operates the operation unit 38 in accordance with this display to perform alignment in the X, Y, and Z directions. Even in this case, if the determination unit 60b determines that the nozzle 21b is close to the subject's face, the stop control unit 60c drives the drive mechanism 13 to stop the alignment, regardless of the operation on the operation unit 38, and the notification control unit 60d issues warning information 64. Then, if a stop release operation is performed on the operation unit 38 after the alignment has been stopped, the stop control of the alignment by the stop control unit 60c may be released.

[0169] In each of the above embodiments, the electrode 36a of the capacitance sensor 36 is formed in a semi-annular shape, but the position (for example, near the nozzle 21b) and shape of the electrode 36a can be changed as appropriate as long as it is possible to detect the approach of the subject's face (eye E) to the nozzle 21b. Also, in each of the above embodiments, one capacitance sensor 36 is provided around the nozzle 21b, but multiple capacitance sensors 36 may be provided around the nozzle 21b. In this case, the determination unit 60b determines that the nozzle 21b is approaching the subject's face when any of the detected capacitance values ​​of the capacitance sensors 36 is greater than a threshold value.

[0170] In each of the above embodiments, a capacitance sensor 36 is used to detect the approach of the nozzle 21b to the subject's face, but one or more known non-contact sensors (proximity sensors), such as an ultrasonic sensor and an infrared proximity sensor, may also be used.

[0171] In each of the above embodiments, air is blown from the nozzle 21b toward the cornea Ec of the eye E to be examined, but various fluids other than air may also be blown.

[0172] In each of the above embodiments, the danger avoidance operation of the present invention involves stopping alignment (stopping movement of the measuring head 14) and retracting the measuring head 14, but instead of stopping movement and retracting the measuring head 14, the danger avoidance operation may involve only issuing warning information 64 by the notification control unit 60d. In this case, the notification control unit 60d and the display unit 15 function as the danger avoidance operation control unit of the present invention.

[0173] In each of the above embodiments, a non-contact tonometer 10 has been used as an example of an ophthalmic device of the present invention, but the present invention can be applied to various ophthalmic devices (including multifunction devices) that acquire various eye characteristics of the subject's eye E. [Explanation of symbols]

[0174] 10. Non-contact tonometer 11. Base 12 Face support 12a Chin rest 12b Forehead support 13 Drive mechanism 14 Measuring head 15 Display section 16 Control device 21 Anterior segment observation optical system 21a Anterior segment illumination light source 21b nozzle 21c Anterior window glass 21d Chamber window glass 21e Half Mirror 21f objective lens 21g Half Mirror 21i image sensor 22 XY alignment index projection optical system 22a XY alignment light source 22b Condenser lens 22c aperture stop 22d Pinhole Plate 22e Dichroic Mirror 22f collimator lens 23 Fixation target projection optical system 23a Fixation target light source 23b Pinhole plate 24 Applanation detection optical system 24a lens 24b Pinhole plate 24c Light receiving sensor 25 Z alignment index projection optical system 25a Z alignment light source 25b Condenser lens 25c aperture stop 25d pinhole plate 25e collimator lens 26 Z alignment detection optical system 26a Imaging lens 26b Cylindrical lens 26c Light receiving sensor 34 Spraying mechanism 34a Chamber 34b Glass plate 34c Pressure sensor 34d cylinder 34e Communication pipe 34f piston 34g solenoid 35 Glass holder 36 Capacitive Sensor 36a electrode 36b Detection circuit 36c wiring 38 Control section 40 Observation control section 42 Fixation control unit 44 Alignment control unit 46 Spray control unit 48 Measurement control section 50 Intraocular pressure value calculation unit 52 Coarse XY alignment control unit 54 Coarse Z alignment control section 56 Fine Z alignment control section 58 Fine XY alignment control unit 60 Monitoring and control unit 60a Detection control section 60b Judgment part 60c Stop control unit 60d Notification control unit 62 XY Spots 64 Warning Information 70 Mode switching control section AX center axis D Observation image E. Examined eye Ec cornea Ep Corneal Apex HL parallel lines O1~O3 optical axis P working position P0 operating position P1 Near position P2 far position Q0 Average corneal position Q1 Anterior corneal position Q2 Posterior corneal position RD detection range SD Standby Distance WD working distance ZR Z detection range

Claims

1. an eye characteristic acquisition unit that acquires eye characteristics of the subject's eye; a drive mechanism that moves the eye characteristic acquisition unit relative to the subject's eye; a relative position detection unit that detects a relative position of the subject's eye with respect to the eye characteristic acquisition unit; an alignment control unit that automatically drives the drive mechanism based on a detection result of the relative position by the relative position detection unit or drives the drive mechanism in response to a manual operation, thereby aligning the eye characteristic acquisition unit with the subject's eye; a detection control unit that causes the relative position detection unit to continue detecting the relative position during the execution of the alignment; one or more non-contact sensors capable of detecting the approach of the eye characteristic acquisition unit to the face of the subject in a non-contact manner; a determination unit that continuously determines whether a detection value of the non-contact sensor has become greater than a predetermined threshold value during the execution of the alignment; a danger avoidance operation control unit that executes a predetermined danger avoidance operation when the relative position detection unit cannot detect the relative position and the determination unit determines that the detection value is greater than the threshold value; and Equipped with The ophthalmologic apparatus is configured such that the alignment control unit continues the alignment when the relative position detection unit detects the relative position or when the determination unit determines that the relative position is not detected.

2. 2. The ophthalmologic apparatus according to claim 1, wherein the danger avoidance operation control unit executes the danger avoidance operation when the relative position detection unit is unable to detect the relative position for a predetermined period of time and the determination unit determines that the detection value has become greater than the threshold value.

3. 2. The ophthalmologic apparatus according to claim 1, wherein the danger avoidance operation control unit counts the number of times that the relative position detection unit is unable to detect the relative position, and executes the danger avoidance operation when the number of times that the detection unit is unable to detect exceeds a predetermined upper limit and when the determination unit determines that the detection value has become greater than the threshold value.

4. The ophthalmologic apparatus according to claim 1 , wherein the determination unit makes the determination when the relative position detection unit cannot detect the relative position.

5. the danger avoidance operation control unit controls the alignment control unit to stop the alignment as the danger avoidance operation, An ophthalmic device according to any one of claims 1 to 4, wherein when the alignment control unit stops the alignment, the alignment control unit controls the drive mechanism to stop relative movement of the eye characteristic acquisition unit with respect to the test eye or to retract the eye characteristic acquisition unit from the test eye.

6. the drive mechanism is capable of moving the eye characteristic acquisition unit relative to the subject's eye in a front-back direction, a left-right direction, and an up-down direction; the relative position detection unit is capable of detecting the relative position in each of three axial directions, i.e., the front-rear direction, the left-right direction, and the up-down direction; the alignment control unit performs the alignment in each of the three axis directions, The ophthalmologic apparatus according to claim 1 , wherein the detection control unit and the determination unit operate only while the alignment in the front-rear direction is being performed.

7. 7. The ophthalmologic device according to claim 1, further comprising an alarm unit that issues warning information when the relative position detection unit is unable to detect the relative position or when the determination unit determines that the detection value has become greater than the threshold value.

8. The ophthalmologic apparatus according to claim 1 , wherein the non-contact sensor is a capacitance sensor.

9. the eye characteristic acquisition unit is a measurement head of a non-contact tonometer having a nozzle that sprays a fluid onto the cornea of ​​the subject's eye, an anterior eye window glass that holds a tip of the nozzle, and a glass holding unit that holds the anterior eye window glass, The ophthalmic apparatus according to claim 1 , wherein the non-contact sensor is provided in the glass holder.

10. A control method for an ophthalmologic apparatus including an eye characteristic acquisition unit that acquires eye characteristics of a subject's eye, a drive mechanism that moves the eye characteristic acquisition unit relative to the subject's eye, and a relative position detection unit that detects a relative position of the subject's eye with respect to the eye characteristic acquisition unit, an alignment control step of automatically driving the drive mechanism based on a detection result of the relative position by the relative position detection unit or by manually driving the drive mechanism to align the eye characteristic acquisition unit with the subject's eye; a detection control step of causing the relative position detection unit to continue detecting the relative position during the execution of the alignment; a determining step of continuously determining whether or not a detection value of one or more non-contact sensors capable of detecting the approach of the eye characteristic acquisition unit to the face of the subject in a non-contact manner has become larger than a predetermined threshold value during the execution of the alignment; a danger avoidance operation step of executing a predetermined danger avoidance operation when the relative position detection unit cannot detect the relative position and when it is determined in the determination step that the detection value is greater than the threshold value; and The alignment control step continues the alignment if the relative position detection unit detects the relative position or if the determination step determines that the relative position is not detected.

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