JP2012183126A - Ophthalmic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ophthalmic equipment which, even when corneal reflex cannot detected, specifies a distance between an equipment body and a subject eye to control a position of the equipment body, consequently enables the equipment body to be smoothly aligned with respect to the subject eye without contacting with the subject eye.SOLUTION: The ophthalmic equipment is configured so that a luminous flux diameter of reflected light from the subject eye E falls within a light receiving surface of a Z alignment two-dimensional detection sensor 60. When a reflected image Ris detected on the light receiving surface of the Z alignment two-dimensional detection sensor 60, a Z alignment signal processing circuit acquires Z luminance distribution information, and a reflected light discrimination circuit uses the Z luminance distribution information to discriminate whether the reflected light is mirror surface reflection of the cornea or diffuse reflection on an eyelid or a cheek. When it is discriminated as the diffuse reflection on the eyelid or the cheek, a position in a Z direction is controlled by a Z direction position control circuit.

Description

  The present invention relates to an ophthalmologic apparatus that performs an examination by aligning an apparatus main body at a predetermined position with respect to an eye to be examined.

  In an ophthalmologic apparatus used for eye examination, it is necessary to align the apparatus main body with a predetermined positional relationship with respect to the eye to be examined. The alignment is performed by projecting an alignment light beam onto the cornea of the eye to be examined, detecting the position of the cornea reflection image (virtual image) with a light receiving element, and operating an operation means such as a joystick based on the detection information. The position of the apparatus main body and the eye to be examined are aligned. In recent years, automatic alignment devices have become mainstream.

  When positioning the device main body and the eye to be inspected using operating means such as a joystick, it is necessary to carefully operate the device main body so that it does not come into contact with the eye to be examined, and the work requires delicate adjustments. , Skill is required.

  Therefore, in order to avoid the contact of the apparatus main body with the eye to be examined, in Patent Document 1 (Japanese Patent Laid-Open No. 2001-275993), the reflected light of the cornea is detected to obtain the deviation information in the Z direction to obtain the eye to be examined. On the other hand, an ophthalmologic apparatus has been proposed that moves the measurement unit backward when it is detected that the measurement unit has approached a predetermined approach distance or more.

  However, in the conventional structure described in Patent Document 1, when the apparatus main body is located at a position where corneal reflection cannot be detected (for example, the eyelid or cheek), the distance between the apparatus main body and the eye to be examined is specified. Therefore, there is a possibility that the main body of the apparatus may come into contact with the eye to be examined.

  In Patent Document 2 (Japanese Patent Laid-Open No. 11-19037), focusing on the fact that the amount of reflected light differs depending on the reflection position of the corneal apex, the eyelid, etc., the amount of light detected by the alignment detection means is relatively In comparison, an ophthalmic apparatus that stops automatic alignment adjustment when corneal reflection is not detected has been proposed.

  However, in the conventional structure described in Patent Document 2, since it is possible to determine which measurement site the reflected light is, when the corneal reflection is not detected, the alignment of the apparatus can be stopped, and the eye to be examined can be obtained. However, since it is not possible to specify the distance between the apparatus main body and the eye to be examined, it is necessary to perform alignment again, which places a burden on the examiner and the subject. is there.

JP 2001-275993 A JP-A-11-19037

  Here, the present invention has been made in the background as described above, and the problem to be solved is that even when corneal reflection cannot be detected, the distance between the apparatus main body and the eye to be examined is determined. It is an object of the present invention to provide an ophthalmologic apparatus that can be smoothly aligned without specifying the position of the apparatus main body and controlling the position of the apparatus main body without contacting the eye to be examined.

  A first aspect of the present invention is a device main body, a Z alignment index light source that irradiates an index light for Z alignment toward the eye to be examined, and reflected light of the index light from the eye to be examined by the Z alignment index light source. An ophthalmologic apparatus comprising: a Z-alignment detecting unit that captures an image with a light receiving element; and a Z-direction driving unit that moves and aligns the apparatus main body in the Z-direction based on a detection result from the Z-alignment detecting unit. A luminance distribution information acquisition unit configured to acquire a luminance distribution information on the light receiving surface received by the light receiving element; and a luminance distribution information acquiring unit configured so that a light beam diameter of the reflected light by the eye to be examined falls within the light receiving surface of the light receiving element Determining means for discriminating whether the reflected light is specular reflection or irregular reflection from the luminance distribution information acquired by the acquisition means; Identifying the distance between the eye and the apparatus main body, in that a and Z-direction position control means for controlling the Z direction position of the apparatus main body, and wherein.

  In the ophthalmologic apparatus structured according to this aspect, the configuration is such that the beam diameter of the reflected light from the eye to be examined falls within the light receiving surface of the light receiving element, so that not only specular reflection of the cornea but also irregular reflection of the eyelids and cheeks Can be detected by the light receiving element, and the distance between the apparatus main body and the eye to be examined can be specified.

  In this aspect, the luminance distribution information in the captured image captured by the light receiving element is acquired, and when the reflected light is determined to be irregular reflection, the distance between the eye to be examined and the apparatus main body is specified, and the Z direction of the apparatus main body is determined. Since the position is controlled, the apparatus main body can be smoothly aligned without contacting the eye to be examined.

  According to a second aspect of the present invention, in the ophthalmologic apparatus according to the first aspect, the light receiving element is a two-dimensional light receiving element, and the luminance distribution information acquisition means is in a vertical or horizontal direction on the light receiving surface. The luminance distribution information of the entire light receiving surface is obtained by integrating the luminance of the pixels on this line for all the lines.

  In the ophthalmologic apparatus structured according to this aspect, the light receiving element is a two-dimensional light receiving element, and the luminance of the pixels on the vertical or horizontal line on the light receiving surface is integrated for all lines, The processing time for acquiring the luminance distribution information of the entire light receiving surface can be more effectively suppressed, and the processing speed can be increased. That is, depending on the specifications of the two-dimensional position detection element, the number of lines may be several hundred. Therefore, evaluating the luminance distribution in each straight line and acquiring the luminance distribution of the entire light receiving surface takes a very long processing time. Cost. In this aspect, after integrating the luminance of the pixels on the vertical or horizontal line on the light receiving surface over all lines, the luminance distribution of the entire light receiving surface is evaluated, so that the processing time is more effective. Therefore, the processing speed can be increased. Further, by integrating the luminance of the pixels on the light receiving surface using a two-dimensional light receiving element, more accurate luminance distribution information can be obtained even if part of the reflected light from the eye to be examined is off the light receiving surface. Can do. That is, in the case of a one-dimensional light receiving element, if a part of the reflected light deviates from the light receiving surface, it is difficult to calculate a peak (center position) in the luminance distribution information. In this aspect, even if a part of the reflected light is off the light receiving surface, it is possible to specify the peak in the luminance distribution information because the luminance of the pixels on the light receiving surface is integrated using the two-dimensional light receiving element. Therefore, the brightness distribution information is more accurate.

  According to a third aspect of the present invention, in the ophthalmologic apparatus according to the first or second aspect, the determination means is a preset luminance in the luminance distribution information obtained by the luminance distribution information acquisition means. It is characterized by discriminating whether the reflected light is specular reflection or irregular reflection based on the number of pixels whose luminance is higher than the threshold value and / or the size of the half width.

  In the ophthalmologic apparatus structured according to this aspect, whether the reflected light is specular reflection or irregular reflection based on the number of pixels having a luminance higher than a preset luminance threshold in the luminance distribution information and / or the size of the half width. Since it is determined, it can be determined by a simple process.

It is a figure which shows the apparatus optical system of an eye refractive power measuring apparatus. It is a figure which shows the state of the light beam which injects into a Z alignment two-dimensional detection sensor when the cornea of a prior art is covered with the eyelid. It is an external view of an eye refractive power measuring apparatus. 1 is a schematic block configuration circuit diagram of an eye refractive power measurement apparatus. It is a flowchart which shows the measurement procedure of an eye refractive power measuring apparatus. It is a figure of the anterior eye part displayed on a display screen. It is a structure schematic diagram of a two-dimensional detection sensor. It is explanatory drawing for demonstrating the method to acquire XY luminance distribution information of the whole light-receiving surface. It is explanatory drawing for demonstrating the method of Z alignment. It is explanatory drawing for demonstrating the reflected image in the light-receiving surface detected with a Z alignment two-dimensional detection sensor. It is explanatory drawing for demonstrating the method to acquire Z luminance distribution information of the whole light-receiving surface. (A) It is a figure which shows Z luminance distribution when detecting irregular reflection of an eyelid, a cheek, etc., when the specular reflection of a cornea is detected.

  Hereinafter, the present embodiment will be described with reference to the drawings. In the present embodiment, an apparatus for measuring eye refractive power will be described as an example.

  First, FIG. 1 shows an apparatus optical system 10 of an eye refractive power measuring apparatus according to the present invention. The apparatus optical system 10 includes an observation optical system (20, 22, 24, 26, 28, 30, 32) for observing the anterior segment of the eye E, and a target optical system for presenting a target for gazing at the eye E. (34, 36, 38, 40, 22), an XY alignment detection optical system as an XY direction position detection means for positioning the device optical system 10 in the vertical and horizontal directions (X and Y directions) with respect to the eye E 42, 44, 46, 48, 38, 40, 22, 24, 26, 28, 50, 52, 54), Z for positioning the device optical system 10 with respect to the eye E in the front-rear direction (Z direction). Z alignment detection optical system (42, 44, 46, 48, 38, 40, 22, 56, 58, 60) as direction position detection means, eye refractive power measurement optical system (42) for measuring eye refractive power , 44, 46, 48, 38, 40, 22, 5 , It is equipped with a 58, 60).

  The observation optical system includes illumination light sources 20 and 20 that irradiate infrared light, a wavelength selection mirror 22, a lens 24, a wavelength selection mirror 26, a half mirror 28, a lens 30, and a CCD 32. Here, the wavelength selection mirror 22 is a half mirror for infrared light emitted from the illumination light sources 20 and 20 and an alignment light source 42 and a measurement light source 62 described later, and reflects visible light from a target light source 32 described later. ing. The wavelength selection mirror 26 transmits infrared light emitted from the illumination light sources 20 and 20 and an alignment light source 42 described later, and reflects infrared light applied from a measurement light source 54 described later. A light beam emitted from the illumination light sources 20 and 20 and reflected by the anterior eye portion of the eye E to be examined passes through the wavelength selection mirror 22, passes through the wavelength selection mirror 26 through the lens 24, and then passes through the lens 28. Guided onto the CCD 30.

  The target optical system includes a target light source 34 that emits visible light, a target 36 that can move in the optical axis direction, a wavelength selection mirror 38, a lens 40, and a wavelength selection mirror 22. Here, the wavelength selection mirror 38 has a characteristic of transmitting visible light and reflecting infrared light of an alignment light source 42 described later. The luminous flux emitted from the target light source 34 passes through the wavelength selection mirror 38 through the target 36, is reflected by the wavelength selection mirror 22 through the lens 40, and is applied to the eye E.

  The XY alignment detection optical system includes an alignment light source 42 that irradiates infrared light, a lens 44, an aperture 46, a lens 48, a wavelength selection mirror 38, a lens 40, a wavelength selection mirror 22, a lens 24, a wavelength selection mirror 26, and a half mirror 28. A filter 50, a lens 52, and an XY alignment two-dimensional detection sensor 54 are provided. Here, the half mirror 28 transmits part of the light from the illumination light sources 20 and 20 and the alignment light source 42 and reflects the rest. In addition, the filter 50 transmits light from the alignment light source 42 and blocks light from the illumination light source 20. For this reason, the light from the illumination light sources 20 and 20 is not detected by the XY alignment two-dimensional detection sensor 54. The diaphragm 46 is disposed at a position conjugate with the cornea C of the eye E, and the diameter of the image of the light beam at the position of the eye E by the alignment light source 42 is adjusted by the diaphragm 46. The light beam emitted from the alignment light source 42 is reflected by the wavelength selection mirror 38 through the lens 44, the stop 46, and the lens 48, is reflected by the wavelength selection mirror 22 through the lens 38, and is applied to the eye E. The light beam specularly reflected by the cornea C of the eye E passes through the wavelength selection mirror 22, passes through the wavelength selection mirror 26 through the lens 24, and then a part of the light beam is reflected by the half mirror 28, and the filter 50 The XY alignment two-dimensional detection sensor 54 is guided through the lens 52.

  The Z alignment detection optical system includes an alignment light source 42 that irradiates infrared light, a lens 44, an aperture 46, a lens 48, a wavelength selection mirror 38, a lens 40, a wavelength selection mirror 22, a filter 56, a lens 58, and Z alignment two-dimensional detection. A sensor 60 is provided. Here, the filter 56 transmits light from the alignment light source 42 while blocking light from the illumination light source 20. For this reason, the light from the illumination light sources 20, 20 is not detected by the Z alignment two-dimensional detection sensor 60. The light beam emitted from the alignment light source 42 is reflected by the wavelength selection mirror 38 through the lens 44, the stop 46, and the lens 48, is reflected by the wavelength selection mirror 22 through the lens 38, and is applied to the eye E. The light beam specularly reflected by the cornea C of the eye E is guided to the Z alignment two-dimensional detection sensor 60 via the filter 56 and the lens 58.

  In particular, in the present embodiment, the light beam irregularly reflected by the eyelids, cheeks, and the like is adjusted by the diaphragm 46 so as to fall on the light receiving surface of the Z alignment two-dimensional detection sensor 60. In the prior art, the light beam irregularly reflected by the eyelids, cheeks, etc. spreads widely and enters the Z alignment two-dimensional detection sensor 60 (see FIG. 2), so that it is difficult to identify the irregular reflection by the Z alignment two-dimensional detection sensor 60. Met. However, in this embodiment, more specifically, for example, the aperture is such that the diameter of the light beam irregularly reflected by the eye E is 80% with respect to the lateral dimension of the light receiving surface of the Z alignment two-dimensional detection sensor 60. The diameter and magnification of 46 are designed and configured to fit on the light receiving surface of the Z alignment two-dimensional detection sensor 60. As a result, detection by the Z alignment two-dimensional detection sensor 60 is possible not only in the specular reflection of the cornea but also in the case of irregular reflection of the eyelids and cheeks.

  The eye refractive power measurement optical system includes a measurement light source 62 for irradiating infrared light, a lens 64, a diaphragm 66, a half mirror 68, a lens 70, a wavelength selection mirror 26, a lens 24, a wavelength selection mirror 22, a diaphragm 72, a lens 74, A CCD 76 movable in the optical axis direction is provided. Here, the half mirror 68 transmits part of the light from the measurement light source 62 and reflects the rest. A part of the light beam emitted from the measurement light source 62 is transmitted by the half mirror 68 through the lens 64 and the diaphragm 66, reflected by the wavelength selection mirror 26 through the lens 70, and wavelength selected through the lens 24. The light is transmitted through the mirror 22 and applied to the fundus of the eye E to be examined. The light beam reflected by the fundus of the subject E passes through the wavelength selection mirror 22, is reflected by the wavelength selection mirror 26 through the lens 24, and part of the light beam is reflected by the half mirror 68 through the lens 70, The light is guided to the CCD 76 through the aperture 72 and the lens 74.

  Next, FIG. 3 shows an external view of the eye refractive power measuring apparatus according to the present invention. The apparatus optical system 10 is accommodated in the eye refractive power measuring apparatus 100 shown in FIG. The eye refractive power measuring apparatus 100 is configured such that a main body 104 is provided on a base 102 and a case 106 is provided on the main body 104 so as to be movable back and forth, right and left and up and down. The base 102 has a built-in power supply device and is provided with an operation stick 108 so that the case 106 can be driven by operating the operation stick 108. Further, the main body unit 104 accommodates control circuits and the like described later, and a display screen 110 including a liquid crystal monitor, for example.

  Furthermore, FIG. 4 shows a schematic block configuration circuit diagram of the eye refractive power measuring apparatus according to the present invention. The eye refractive power measurement device is provided with a drive circuit 112 as a drive means of the device optical system 10. The X-axis drive mechanism 114, the Y-axis drive mechanism 116, and the Z-axis drive mechanism 118 are connected to the drive circuit 112, respectively, and are driven based on a drive signal from the drive circuit 112. The XY alignment two-dimensional detection sensor 54 is connected to the XY alignment signal processing circuit 120, and the XY alignment signal processing circuit 120 is connected to the drive circuit 112. The Z-alignment two-dimensional detection sensor 60 is connected to a Z-alignment signal processing circuit 122, and the Z-alignment signal processing circuit 122 discriminates reflected light as discrimination means for discriminating whether reflected light is specular reflection or irregular reflection. The circuit 124 is connected to the driving circuit 112. Thereby, detection information of the XY alignment two-dimensional detection sensor 54 and the Z alignment two-dimensional detection sensor 60 is input to the drive circuit 112. A Z-direction position control circuit 126 is connected to the drive circuit 112 as Z-direction position control means for controlling the position of the apparatus optical system 10 in the Z direction. Further, a measuring system 128 for measuring the eye refractive power is connected to the driving circuit 112 in the eye refractive power measuring apparatus.

  Next, in the eye refractive power measuring apparatus having such a structure, an outline of the eye refractive power measurement procedure executed by the drive circuit 112 is shown in FIG.

First, in S <b> 1, alignment of the apparatus optical system 10 in the X direction and the Y direction (XY alignment) is manually performed on the eye E to be examined. During such XY alignment, the target light emitted from the target light source 34 is guided to the eye E. Then, by fixing an according target light to the subject, the optical axis of the eye E, it is possible to match the direction of the optical axis O ₁ of the observation optical system. Under such a state, the light beam emitted from the illumination light sources 20 and 20 and reflected by the anterior eye portion of the eye E is guided onto the CCD 32. As a result, as shown in FIG. 6, the anterior segment of the eye E is displayed on the display screen 110.

Further, on the display screen 110, an XY alignment detectable region 130 having a rectangular frame shape indicating a region in which the position in the X direction and the position in the Y direction can be detected by the XY alignment two-dimensional detection sensor 54 is superimposed on the eye E. Displayed. At the same time, the light beam emitted from the alignment light source 42 toward the subject eye E is reflected by the cornea C of the subject eye E and guided to the CCD 32, so that a dotted corneal bright spot R _XY is displayed on the display screen 110. It is displayed. Then, the operator operates the operation stick 108 to drive the apparatus optical system 10 so that the position of the apparatus optical system 10 is adjusted so that the corneal bright spot R _XY falls within the frame of the XY alignment detectable region 130. Adjust.

  Further, a part of the light beam irradiated by the alignment light source 42 and reflected by the anterior eye portion of the eye E is reflected by the half mirror 28 and guided to the XY alignment two-dimensional detection sensor 54. .

Next, in S2, the XY alignment two-dimensional detection sensor 54 enters the corneal bright spot R _XY within the frame of the XY alignment detectable region 130, and when the corneal bright spot R _XY is detected, the XY alignment signal processing circuit 120. Is input. The XY alignment signal processing circuit 120 acquires XY luminance distribution information. More specifically, as shown in FIG. 7, the XY alignment two-dimensional detection sensor 54 is composed of m columns in the horizontal direction and n rows in the vertical direction, and the column and row numbers start from 0. Shall. As shown in FIG. 8, by integrating the luminance of the pixels on the vertical line l _Xi (i = 0 to m) and the horizontal line l _Yj (j = 0 to n) on the light receiving surface, XY luminance distribution information of the entire surface is acquired. Then, the X direction and Y direction positions obtained from the XY luminance distribution information are output to the drive circuit 112.

Next, in S3, the driving circuit 112 together with the optical axis O ₁ of the observation optical system based on the position information in the X direction to drive the X-axis driving mechanism 114 closer to the optical axis of the eye E, Y-direction Based on the position information, the Y-axis drive mechanism 116 is driven so that the optical axis O ₁ of the observation optical system approaches the optical axis of the eye E to be examined. Thereby, the alignment of the apparatus optical system 10 with respect to the eye E in the XY directions is performed.

  Next, in S4, the apparatus optical system 10 is manually aligned in the Z direction (Z alignment) with respect to the eye E. At the time of such Z alignment, the alignment light source 42 is caused to emit light, and the infrared light beam emitted from the alignment light source 42 is irradiated from the front to the anterior eye part of the eye E, and the light beam reflected from the anterior eye part is reflected. The Z alignment two-dimensional detection sensor 60 is guided.

9, when the eye E is moved back and forth in the Z direction relative to the Z alignment detection optical system, the reflected light flux reflected from the eye E: O _Z1 and O _Z2. Is incident on the Z alignment two-dimensional detection sensor 60, and is shifted from the incident position of the reflected light beam: O _Z0 reflected from the eye E to be examined positioned at the target reference position. As a result, as shown in FIG. 10 as a model, the reflected light beam deviated from the target position: O _Z1 , O _Z2 , the reflected image on the light receiving surface detected by the Z alignment two-dimensional detection sensor 60: R _Z1 , The position of R _{Z2 deviates from} the position of the reflected image: R _Z0 (reference position, offset amount = 0) detected by the reflected light beam O _{Z0 at} the target Z-direction position. Accordingly, it is possible to specify the distance between the apparatus optical system 10 and the eye E based on the offset amount from the reference position of the reflected image detected by the Z alignment two-dimensional detection sensor 60.

Next, in S <b> 5, when the reflected image _RZ is detected on the light receiving surface, the Z alignment two-dimensional detection sensor 60 is input to the Z alignment signal processing circuit 122. The Z alignment signal processing circuit 122 acquires Z luminance distribution information. More specifically, similarly to the XY alignment two-dimensional detection sensor 54, the Z alignment two-dimensional detection sensor 60 is composed of pixels in m columns in the horizontal direction and n rows in the vertical direction. Shall start from 0. As shown in FIG. 11, the Z luminance distribution information of the entire light receiving surface is acquired by integrating the luminance of the pixels on the vertical line l _Zi (i = 0 to m) on the light receiving surface. FIG. 12 shows Z luminance distribution information acquired when (a) specular reflection of the cornea is detected, and (b) irregular reflection such as an eyelid or cheek is detected.

  Next, in S6, the Z luminance distribution information acquired by the Z alignment signal processing circuit 122 is processed by the reflected light determination circuit 124 to determine whether the reflected light is irregular reflection such as specular reflection of the cornea, eyelids or cheeks. As a first determination in the reflected light determination circuit 124, in the present embodiment, the brightness value higher than the first threshold value of the brightness value set in advance using the Z brightness distribution information acquired by the Z alignment signal processing circuit 122. It is determined whether or not there is a pixel having. The first threshold value of the brightness value set in advance is more specifically set to the brightness value 128 when the brightness value is represented by 0 to 255, for example.

  Here, in the first determination in the reflected light determination circuit 124, when a pixel having a luminance higher than the first threshold is not detected, it is estimated that the reflected light is irregular reflection such as eyelids and cheeks. The process of S7 is performed.

  On the other hand, in the first determination in the reflected light determination circuit 124, when a pixel having a luminance higher than the first threshold is detected, it is determined that the reflected light is a specular reflection of the cornea. In this case, the process of S9 is performed.

Next, in S7, in the present embodiment, as the second determination in the reflected light determination circuit 124, in the present embodiment, the Z brightness distribution information acquired by the Z alignment signal processing circuit 122 is used, and a preset second threshold value is exceeded. It is determined whether or not the full width at half maximum. Incidentally, the second threshold value is set in advance, more specifically, for example, it is set at five times the size of the diameter of the corneal bright points R _XY.

  Here, in the second determination in the reflected light determination circuit 124, when the half-value width exceeds a preset second threshold value, it is determined that the reflected light is irregular reflection such as an eyelid or a cheek. Next, the process of S8 is performed.

  On the other hand, in the second determination in the reflected light determination circuit 124, if the half width exceeding the preset second threshold value is not reached, it is determined that the reflected light is specular reflection of the cornea, and in S9 Processing is performed.

  In S8, the drive circuit 112 inputs to the Z direction position control circuit 126 so as to control the position in the Z direction. The Z direction position control circuit 126 controls the position in the Z direction so that the apparatus optical system 10 does not approach the eye E to be examined more than a preset approach distance. Then, the process of S4 is performed again.

  In S9, when the reflected light determination circuit 124 determines that the reflected light is a specular reflection of the cornea, the drive circuit 112 uses the Z-axis position information detected by the Z alignment signal processing circuit 122 as the Z-axis. By driving the drive mechanism 118 forward or backward in the Z direction, the alignment of the apparatus optical system 10 in the Z direction with respect to the eye E is performed.

  After the alignment in the XY direction and the Z direction is performed in this way, in S10, the drive circuit 112 inputs to the measurement system 128 to measure the eye refractive power. The eye refractive power measurement is performed by projecting measurement light onto the fundus of the subject eye E, receiving reflected light from the fundus of the subject eye E, and calculating using the information of the obtained reflected light to refract the subject eye E. Although the force is measured, the description of the measurement mechanism itself is not related to the present invention, and is therefore omitted. For details of the measurement mechanism, refer to Japanese Patent Application Laid-Open No. 2003-102687 by the present applicant.

  As mentioned above, although one embodiment of the present invention has been described in detail, the present invention is not limited in any way by the specific description in the embodiment, and various changes, modifications, and modifications based on the knowledge of those skilled in the art. Needless to say, the present invention can be implemented in a mode with improvements and the like, and all such modes are included in the scope of the present invention without departing from the gist of the present invention.

For example, in this embodiment, when the eye E is relatively back and forth in the Z direction relative to the Z alignment detection optical system, the horizontal reflection image R _Z is a receiving surface which is detected by the Z alignment 2D sensor 60 However, a configuration is disclosed in which the luminance of the pixels on the vertical line l _Zi (i = 0 to m) is integrated. However, the reflected image R _Z is shifted in the vertical direction. In the case of an optical arrangement for shifting, the luminances of the pixels on the horizontal line are integrated.

  In the present embodiment, the reflected light determination circuit 124 performs the first determination that determines whether or not there is a pixel having a luminance value higher than the first threshold value of the predetermined luminance value, and is set in advance. The second determination for determining whether or not the half-value width exceeds the second threshold is performed, but the present invention is not limited to this, and a pixel having a luminance value higher than the first threshold of the preset luminance value is determined. Only the first determination for determining whether or not it exists may be adopted. By performing both the first determination and the second determination, it is possible to determine whether the reflected light is specular reflection or irregular reflection more accurately.

  In the present embodiment, the Z alignment two-dimensional detection sensor 60 is used. However, the present invention is not limited to this, and a one-dimensional detection sensor may be used.

  In the present embodiment, in the Z alignment detection optical system, the light beam from the alignment light source 42 is projected from the front onto the eye to be examined and is received by the Z alignment two-dimensional detection sensor 60 from an oblique direction. The present invention is not limited, and a configuration in which a light beam is projected obliquely on the eye to be examined and light is received obliquely, or a configuration in which the light beam is projected obliquely on the eye to be examined and received from the front may be employed.

  Further, the use in the eye refractive power measurement device shown in the present embodiment is merely an example, and can be adopted in a device that performs alignment driving in the Z direction with respect to the eye E, for example, a tonometer or a corneal shape measurement device. Needless to say.

DESCRIPTION OF SYMBOLS 100 Eye refractive power measuring apparatus 102 Base 104 Main body part 106 Case 108 Operation stick 112 Drive circuit 114 X-axis drive mechanism 116 Y-axis drive mechanism 118 Z-axis drive mechanism 120 XY alignment signal processing circuit 122 Z alignment signal processing circuit 124 Reflected light discrimination Circuit 126 Z-direction position control circuit 128 Measurement system

Claims (3)

An apparatus main body, a Z alignment index light source that irradiates an index light for Z alignment toward the eye to be examined, and a Z alignment detection unit that images the reflected light of the index light from the eye to be examined by the Z alignment index light source using a light receiving element And an Ophthalmic device comprising Z direction driving means for moving and aligning the apparatus main body in the Z direction based on a detection result from the Z alignment detecting means,
A luminance distribution information acquisition unit configured to acquire a luminance distribution information on the light receiving surface received by the light receiving element, and configured so that a light beam diameter of the reflected light from the eye to be examined falls within the light receiving surface of the light receiving element; A discriminating unit for discriminating whether the reflected light is specular reflection or irregular reflection from the luminance distribution information acquired by the information acquiring unit; and when the discriminating unit determines that the reflected light is irregular reflection, the distance between the eye to be examined and the apparatus main body is determined. An ophthalmic apparatus comprising: a Z-direction position control unit that identifies and controls the position of the apparatus body in the Z direction.   The light receiving element is a two-dimensional light receiving element, and the luminance distribution information acquisition means integrates the luminance of pixels on a vertical or horizontal line on the light receiving surface for all the lines. The ophthalmic apparatus according to claim 1, wherein luminance distribution information of the entire surface is acquired.   The discriminating unit determines whether the reflected light is based on the number of pixels having a luminance higher than a preset luminance threshold in the luminance distribution information obtained by the luminance distribution information acquisition unit and / or the size of the half-value width. The ophthalmologic apparatus according to claim 1, wherein it is discriminated whether it is specular reflection or irregular reflection.

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