JP6454964B2 - Interpupillary distance meter - Google Patents

Description

  The present invention relates to an interpupillary distance meter for measuring the interpupillary distance of an eye to be examined.

  In the adjustment of the glasses, the main optical axis of the lens must match the optical axis of the corresponding eyeball under a gaze distance in an average use state (this is also referred to as a working distance). For this purpose, it is necessary to measure the distance between the optical axes of the eyeball of the subject (distance between pupils).

  Conventionally, the position of the pupil is determined by matching the position of the corneal bright spot, which is a virtual image of the illumination light formed on the cornea of the eye to be examined, and the hairline (measurement mark) displayed on the liquid crystal. An interpupillary distance meter that measures distance is known (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 1-158933 JP-A-2-154734

  However, conventionally, the position of the corneal bright spot and the hairline displayed on the liquid crystal are not aligned, and an error may occur in the interpupillary distance.

  In view of the above problems, an object of the present invention is to provide an interpupillary distance meter that can satisfactorily measure the interpupillary distance.

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

(1) An interpupillary distance meter that measures the interpupillary distance of a subject by detecting the positions of the subject's eyes in both the left and right eyes, and irradiates light toward the subject's eye through an examination window Measuring mark forming means arranged between the eye and the eye to be examined and the fixation target, and forming a measurement mark on the eye to be examined, wherein the first measurement mark is used as the measurement mark. display common and two measuring marks, and the first measuring mark or the second measuring mark and a second measurement mark formed on the first measuring mark and a position different from the A measurement mark forming means for forming a single measurement mark formed in the region, and the measurement mark for a cornea reflection image formed on the cornea of the eye to be examined by light from the irradiation means Mark for measurement to move the formation position of In the first position detection mode , the moving means, the first eye position detection mode, and the second eye position detection mode are switched. The first position detection mode is aligned with the corneal reflection image. The position of the eye to be examined is detected based on a single formation position by the single measurement mark, and the first measurement is aligned with the cornea reflection image in the second position detection mode. a first forming position by use marks, based on the second forming position of the second measuring mark which is aligned with respect to the cornea reflection image at a position different from the first forming position, the characterized in that it comprises the eye position detecting means for detecting the position of the eye, the.

It is the schematic which shows the external appearance of a present Example. It is an external view when a present Example is seen from the subject side. It is the schematic which shows the optical system of a present Example. It is a block diagram which shows the control system of a present Example. It is a figure for demonstrating the display method of the mark for a measurement in a present Example. It is a figure for demonstrating the display method of the mark for a measurement of a present Example. It is a figure for demonstrating the display method of the mark for a measurement of a present Example.

<Overview>
The outline of this embodiment will be described below. The interpupillary distance meter 1 (see FIG. 1) of the present embodiment measures the distance between the pupils of the subject by detecting the positions of the left and right eye to be examined. Note that the positions of the left and right eyes may be detected separately. When measuring the interpupillary distance, the distance from one pupil of the left and right eyes to the other pupil may be measured, or based on the distance from the center of the face (for example, the nose) to the respective pupils of the left and right eyes. May be measured.

  The interpupillary distance meter 1 according to the present embodiment includes an irradiation unit (for example, a fixation target illumination light source 31 (see FIG. 3)), a measurement mark forming unit (for example, a display 36), and a measurement mark moving unit (for example). For example, it mainly includes a control unit 70 (see FIG. 4) and an eye position detection unit (for example, the control unit 70).

  For example, the irradiating unit irradiates light toward the eye to be examined through an examination window. For the irradiation unit, for example, an LED, a light bulb, or another light source may be used. The irradiation unit may also be used as an illumination light source that illuminates the fixation target.

<Measurement mark forming section>
The measurement mark forming unit is disposed, for example, between the eye E and the fixation target. In addition, the measurement mark forming unit forms a measurement mark for the eye E. The measurement mark is a mark for positioning with the pupil of the subject, for example. For example, the measurement mark may have a line shape or a polygonal shape in the vertical direction of the subject. The measurement mark only needs to be aligned with the pupil of the eye E to be examined.

  The measurement mark forming unit may be a display 36 such as a liquid crystal display or an organic EL display, for example. For example, the measurement mark forming unit may be a segment type liquid crystal display, a matrix type display, or the like. Further, the measurement mark forming unit may be a monochrome display, a color display, or the like. The display 36 may be a digital display capable of digitally displaying the measurement mark.

  The measurement mark forming unit may form the first measurement mark M and the second measurement mark Ms formed at a position different from the first measurement mark M. The measurement mark forming unit may simultaneously form two measurement marks including the first measurement mark M and the second measurement mark Ms. However, it is not always necessary to form two measurement marks simultaneously.

<Measurement mark moving part>
For example, the measurement mark moving unit moves the measurement mark forming position with respect to a cornea reflection image (corneal bright spot) formed on the cornea of the eye to be examined by light from the irradiation unit.

  The measurement mark moving unit may be, for example, a display control unit that controls display such as a display used in the measurement mark forming unit. For example, the display control unit may control the display of the display 36 based on an operation signal from an operation unit operated by an examiner.

  The measurement mark moving unit measures, for example, a first formation position corresponding to the first pixel of the display 36 and a second formation position corresponding to the second pixel adjacent to the first pixel. A mark for use may be formed. For example, in the segment type liquid crystal display or the like, the measurement mark moving unit includes a first formation position corresponding to the first segment and a second formation corresponding to the second segment adjacent to the first segment. A measurement mark may be formed at a position.

<Eye position detection unit>
The eye position detection unit (for example, the control unit 70) converts, for example, the first formation position of the measurement mark aligned with the corneal reflection image and the corneal reflection image at a position different from the first formation position. The position of the eye to be examined is detected based on the second formation position of the measurement mark aligned with the measurement mark. For example, the eye position detection unit may calculate the position of the eye to be examined from the first formation position and the second formation position. Further, the eye position detection unit may read the position of the eye to be examined associated with the first formation position and the second formation position from the storage unit (for example, the memory 72), for example.

<Detection mode switching section>
The distance meter 1 may include a detection mode switching unit (for example, the control unit 70). The detection mode switching unit includes, for example, a first eye position detection mode for detecting the position of the eye E based on a single formation position by a single measurement mark, and a first measurement by a first measurement mark. You may switch between a formation position and the 2nd eye position detection mode which detects the position of the eye E based on the 2nd formation position by the 2nd measurement mark.

<Example>
Embodiments of the present invention will be described below with reference to the drawings. The interpupillary distance meter (hereinafter also referred to as the present distance meter) 1 of the present embodiment is a device for measuring the distance between the pupils of the subject. For example, the distance meter 1 irradiates the eye to be examined with illumination light to form a bright spot at the apex of the cornea. This bright spot is a virtual image of the illumination light and is formed at the position of the corneal apex. The distance meter 1 measures the distance between the pupils of the subject based on the bright spots formed at the left and right corneal apexes and the position of the machine center of the distance meter 1.

<Appearance>
With reference to FIG. 1, FIG. 2, the external appearance of this distance meter 1 is demonstrated. FIG. 1 shows an overview of the interpupillary distance meter 1 of this embodiment as viewed from above. FIG. 2 is an external view of the interpupillary distance meter 1 according to the present embodiment when viewed from the W direction in FIG.

  The distance meter 1 mainly includes a housing 2, a forehead pad 3, a nose pad 4, an observation window 5, an inspection window 6 (see FIG. 6), and a display unit 7. The housing 2 includes a power button 21, measurement mark movement buttons (hereinafter also referred to as movement buttons) 22R and 22L, measurement mark movement buttons (hereinafter also referred to as movement buttons) 23R and 23L, and a measurement mode switching button. 24, a work distance change button 25, and the like are arranged. The measurement mark moving buttons 22R and 22L are used to move a measurement mark (described later) displayed on the right eye side of the subject to the left and right. The measurement mark moving buttons 23R and 23L are used to move a measurement mark, which will be described later, displayed on the left eye side of the subject to the left and right. The measurement mode switching button 24 is used to switch the measurement mode to any one of the right eye measurement mode, the left eye measurement mode, and the binocular measurement mode. The work distance change button 25 is used to change the work distance used for calculating the interpupillary distance. A measurement optical system 30 (to be described later) is housed inside the housing 2.

  The forehead pad 3 is brought into contact with the forehead of the subject and is used to fix the position of the subject and the distance meter 1. The nose pad 4 is brought into contact with the subject's nose and is used to match the subject's nose with the machine center of the distance meter 1. The observation window 5 is used by the examiner to observe the eye to be examined. The inspection window 6 is used for allowing the subject to observe a fixation target described later. The display unit 7 is used to display the measured interpupillary distance and the like.

<Measurement optical system>
With reference to FIG. 3, the measurement optical system 30 of the distance meter 1 will be described. The measurement optical system 30 of the distance meter 1 mainly includes a fixation target illumination light source 31, a fixation target 32, a mirror 33, a convex lens 34, an eyepiece lens 35, and a display 36.

  The fixation target illumination light source 31 illuminates the fixation target 32 from behind. The fixation target illumination light source 31 functions as an irradiation means for irradiating light toward the eye to be examined. The focal length and the arrangement of the convex lens 34 are considered so that the fixation target can be easily seen.

  In this embodiment, the fixation target presentation distance (working distance) is fixed. However, if the interpupillary distance at a certain working distance is known, the interpupillary distance at a different working distance can be calculated. Therefore, in this embodiment, it is possible to measure the interpupillary distance at an arbitrary working distance by correcting the interpupillary distance data measured by the interpupillary distance meter 1. In the present embodiment, an arbitrary work distance is selected by a work distance change button 25 from preset work distances.

  For example, based on the measured interpupillary distance and the set work distance data, the control unit 70 calculates the interpupillary distance for the set work distance from the following equation. PDn is calculated by the following equation, where PDm is the distance between the pupils at the known working distance Dm, which is unique to the distance meter 1, and PDn is the distance between the pupils at the calculated working distance Dn.

  Note that VD is a corneal apex distance (for example, Japanese is calculated as 12 mm), R is an eyeball turning radius (for example, 13 mm), and can be handled as a constant in relation to measurement accuracy. L is the distance between the corneal apex of the eye to be inspected at infinity and the display 36, and is a known value in design. The interpupillary distance obtained in this way may be stored in the memory 72 in advance, for example. Note that the method described in Patent Document 1 and Patent Document 2 may be used as a method for calculating the interpupillary distance.

  As described above, by performing the correction calculation, it is possible to measure the interpupillary distance at an arbitrary working distance. For this reason, in this embodiment, the working distance is set to a short distance so that the subject can easily fuse the fixation target. The eyepiece 35 is used when the examiner observes a bright spot formed on the subject's cornea. The eyepiece 35 is considered so that the vicinity of the bright spot formed on the cornea is focused. The display 36 forms measurement marks to be described later. The display 36 functions as a measurement mark forming unit.

  The display 36 of the present embodiment uses a segment type liquid crystal display which is a kind of transmissive display. Each segment of the segment type liquid crystal display is manufactured by photo-etching glass with a transparent metal coating. However, it may not be a segment type liquid crystal, and for example, a matrix type liquid crystal may be used. The segment type liquid crystal is described in Patent Document 2.

  The display 36 is disposed between the fixation target 32 and the cornea of the eye to be examined. For example, the display 36 is disposed at a position 30 mm from the apex of the subject's cornea, but is not limited thereto. The distance from the display 36 to the apex of the cornea only needs to be known and easy to calculate.

<Control system>
A control system of the distance meter 1 will be described with reference to FIG. The control system of the distance meter 1 mainly includes a control unit 70 having a CPU 71, a memory 72, and the like. The control unit 70 includes a display unit 7, a power button 21, measurement mark movement buttons 22R and 22L, measurement mark movement buttons 23R and 23L, a measurement mode switching button 24, a work distance change button 25, The target illumination light source 31 is connected to the display 36 or the like.

  FIG. 5 is a schematic view showing the display 36 used in this embodiment. The display 36 displays a line-shaped measurement mark M extending in the vertical direction of the subject. A large number of line-shaped segments are arranged on the display 36 in the vertical direction. For convenience of explanation in FIGS. 5 to 7, each segment region is indicated by a solid line.

  The display 36 displays the measurement mark M by polarizing and displaying each segment. For example, when a voltage is applied to both ends of a certain segment, the action of the liquid crystal that bends the plane of polarization is lost, and that portion cannot transmit light by the polarizing plate and appears as a dark line (measurement mark M). The display 36 of this embodiment has a segment width of 0.4 mm and a pitch (interval) between the segments of 0.1 mm. That is, in the display 36 used in this embodiment, the distance between the centers of the segments is 0.5 mm. Therefore, the control unit 70 can move the formation position of the measurement mark M formed on the display 36 in 0.5 mm steps. Note that the measurement mark is not necessarily in the form of a line, and may be any mark that can be aligned.

<Operation method and control action>
Hereinafter, the operation method of the interpupillary distance meter 1 of the present embodiment will be described with the control of the interpupillary distance meter 1. First, the examiner operates the power button 21 to turn on the interpupillary distance meter 1. When the power is turned on, the control unit 70 turns on the fixation target illumination target light source 31.

  Then, the measurement mode switching button 24 is operated to switch the binocular measurement mode, the right eye measurement mode, and the left eye measurement mode, and switch to the desired measurement mode. Each measurement mode is switched each time the measurement mode switching button 24 is operated by the examiner. In the following description, for example, it is assumed that the binocular measurement mode is selected.

  Next, the examiner presses the work distance change button 25 to change the setting of the work distance. For example, the control unit 70 switches the work distance such as 30 cm, 40 cm, 50 cm, 60 cm, 1 m, 2 m, or infinity every time the work distance change button 25 is pressed. The control unit 70 may display the selected work distance on the display unit 7. As described above, the interpupillary distance data measured by the distance meter 1 is corrected and calculated to indirectly measure the interpupillary distance of the subject at the selected working distance. The working distance setting may be changed after the measurement.

  Subsequently, the examiner applies the forehead pad 3 of the interpupillary distance meter 1 to the forehead of the subject. The examiner places the nose pad 4 on the subject's nose. Then, the examiner causes the examinee to look into the examination window 6 to fixate the fixation target.

  Illumination light emitted from the fixation target illumination light source 31 and illuminating the fixation target 32 is reflected by the mirror 33 and enters the cornea via the convex lens 34. The cornea surface acts as a convex mirror and forms a virtual image. This virtual image appears as a fine bright spot because the curvature of the cornea is small. If the subject is fixing the fixation target 32, the visual axes of both eyes of the subject intersect at the working distance point, and the bright spot on the cornea is located on the top of the cornea.

  The examiner looks through the observation window 5 and observes the bright spot formed on the eye through the eyepiece lens 35. Then, the examiner operates the movement buttons 22R and 22L and 23R and 23L to move the measurement mark M so as to overlap the corneal bright spot. The control unit 70 receives operation signals from the measurement mark moving buttons 22R and 22L and the measurement mark moving buttons 23R and 23L, and controls and moves the display position of the measurement mark M. As described above, the control unit 70 functions as a measurement mark moving unit that moves the formation position of the measurement mark formed on the display 36.

  A method of moving the measurement mark M will be described with reference to FIG. FIG. 5 shows a state when the right eye of the subject is observed from the observation window 5. First, the case where the corneal bright spot is located in one segment as shown in FIG. 5 will be described. For example, it is assumed that the corneal bright point P is in the segment c. Assume that the measurement mark M is displayed in the segment b (see FIG. 5A). For example, the control unit 70 can identify the segment displaying the measurement mark M. For example, the control unit 70 reads the distance corresponding to the segment displaying the measurement mark M and the work distance selected by the working distance change button 25 from the memory 72. The control unit may display the distance read from the memory 72 on the display unit 7. Of course, not only the corresponding distance is read from the memory 72, but it may be calculated and calculated each time the position of the measurement mark M is changed. As described above, the control unit 70 functions as an eye position detection unit that detects the position of the eye to be examined. For example, when the measurement mark is displayed in the segment b and the working distance is set to 1 m, it is assumed that the pupil distance of the right eye displayed on the display unit 7 is 33.00 mm.

  The examiner presses the movement button 22R to move the measurement mark M to the right side. The control unit 70 acquires an operation signal from the movement button 22R and controls display on the display 36. The control unit 70 identifies in which segment the measurement mark M is displayed. When the move button 22R is pressed, the control unit 70 displays the second measurement mark Ms on the segment c adjacent to the right with the first measurement mark M displayed on the segment b (FIG. 5 ( b)). At this time, the control unit 70 detects an intermediate position between the segment b and the segment c as a pupil position, and the measurement value is read from the memory 72. For example, the display unit 7 displays 32.75 mm as the pupil distance of the right eye (the distance from the machine center of the distance meter 1 to the pupil).

  The examiner further presses the movement button 22R. When the movement button 22R is pressed, the control unit 70 displays the measurement mark M only on the segment c (see FIG. 5C). That is, one measurement mark M and a corneal bright spot P are overlapped. At this time, the control unit 70 determines the position of the center of the segment c as the position of the pupil, and the measurement value is read from the memory 72. For example, the display unit 7 displays 32.50 mm as the pupil distance of the right eye.

  As described above, the control unit 70 displays the first measurement mark M and the second measurement mark M when the first measurement mark M is displayed each time the movement buttons 22R and 22L or the movement buttons 23R and 23L are pressed. When the measurement mark Ms is displayed, the display is switched alternately. The distance meter 1 measures the interpupillary distance in increments of 0.25 mm, assuming that the measurement mark display step is at intervals of 0.5 mm.

  Next, as shown in FIGS. 6 and 7, the case where the corneal bright spot Q is located between the segments will be described. For example, it is assumed that the corneal bright point Q is at an intermediate position between the segment d and the segment e. It is assumed that the measurement mark M is displayed in the segment c (see FIG. 6A). At this time, it is assumed that the pupil distance of the right eye displayed on the display unit 7 is 32.50 mm.

  As described above, the examiner moves the measurement mark M in the direction of the corneal bright spot Q by pressing the movement buttons 22R, 22L or the movement buttons 23R, 23L. In the case of FIG. 6, the examiner presses the movement button 22R three times. Similarly to the above, the control unit 70 switches the display of the first measurement mark M and the second measurement mark Ms each time the movement button 22R is pressed.

  For example, when the movement button 22R is pressed once in the state of FIG. 6A, the control unit 70 displays the first measurement mark M on the segment c and the second measurement mark Ms on the segment d. Displayed (see FIG. 6B). Then, the control unit 70 reads the measurement value from the memory 72 with the position between the segment c and the segment d as the pupil position. Then, the control unit 70 displays the measurement value on the display unit 7. For example, the control unit 70 displays 32.25 mm on the display unit 7 as the pupil distance of the right eye.

  When the movement button 22R is pressed once in the state of FIG. 6B, the control unit 70 controls the display on the display to display the first measurement mark M on the segment d (FIG. 6C). reference). And the control part 70 displays 32.00 mm on the display part 7 as a measured value of the pupil distance of a right eye, for example.

  When the movement button 22R is pressed once in the state of FIG. 6B, the control unit 70 displays the first measurement mark M on the segment d and the second measurement mark Ms on the segment e. (See FIG. 7A).

  In this way, the control unit 70 sequentially switches the display of the measurement mark M every time the movement buttons 22R, 22L, 23R, and 23L are pressed. In the above example, the control unit 70 displays the first measurement mark M and the second measurement mark Ms each time the first measurement mark M is displayed each time the movement button 22R is pressed. The detection position of the pupil is moved in the direction of the corneal luminescent point Q in steps of 0.25 mm while alternately switching between the cases of FIG. 6 (a) to FIG. 7 (a).

  From the state shown in FIG. 6A, when the movement button 22R is pressed three times, the first measurement mark M is displayed in the segment d, and the second measurement mark Ms is displayed in the segment e. (See FIG. 7 (a)). At this time, the control unit 70 determines the position between the segment d and the segment e, that is, the position where the corneal bright spot Q is formed as the position of the pupil of the eye to be examined. Then, the measurement value is read from the memory 72 by the control unit 70, and the measurement value read from the memory 72 is displayed on the display unit 7. For example, the control unit 70 displays 31.75 mm as the right eye pupil distance on the display unit.

  Note that the same measurement is performed on the left eye to measure the distance between the pupils of the left and right eyes.

  Thus, the control unit 70 of the present embodiment measures the interpupillary distance from the positions of the two measurement marks. Thereby, even if a corneal bright spot exists in the middle of each segment, the position of the pupil can be determined more accurately.

  Further, by measuring the distance between the pupils from the positions of the two measurement marks, it is possible to perform measurement with higher accuracy. For example, the resolution can be doubled by measuring an intermediate position between two measurement marks.

  For example, if a display with a high resolution is used in order to increase the resolution, the width of one pixel becomes narrow, and the visibility of the measurement mark decreases. However, in this embodiment, the resolution can be increased while maintaining the visibility of the measurement mark without using a display with high resolution.

  For example, in the state shown in FIG. 7A, when the measurement mark moving button 22R is pressed once, the measurement mark M is displayed only in the segment e (see FIG. 7B). . In this case, the control unit 70 determines the position of the pupil based on the center position of the segment b.

  In the above description, the mode for detecting the position of the eye to be inspected based on the single formation position by the single measurement mark M is set as the first eye position detection mode, and the first measurement mark by the first measurement mark is used. A mode in which the eye position of the eye to be examined is detected based on the formation position of the eye and the second formation position by the second measurement mark is referred to as a second eye position detection mode. Then, in the present embodiment, the control unit 70 switches between the first eye position detection mode and the second eye position detection mode. For example, in this embodiment, the control unit 70 alternately switches between the first eye position detection mode and the second eye position detection mode. From the above, it can be said that the control unit 70 functions as detection mode switching means.

  In the above description, the first eye position detection mode and the second eye position detection mode are each assigned the detection position of the eye to be examined in 0.5 mm steps. For example, in this embodiment, since the distance between the centers of the segments is 0.5 mm, the eye to be inspected can be used both when detecting the eye position at the center of the segment and when detecting the eye position between the two segments. The interval between the detection positions is 0.5 mm.

  Therefore, by using both the first eye position detection mode and the second eye position detection mode, the eye position can be detected every 0.25 mm. That is, in the first eye position detection mode and the second eye position detection mode, the detection position of the eye to be examined is assigned in steps of 0.5 mm, and two detection positions adjacent to each other in the first eye position detection mode. A detection position in the second eye position detection mode is assigned to the intermediate position, and the eye position detection means is used in steps of 0.25 mm in combination with the first eye position detection mode and the second eye position detection mode. Thus, the detection position of the eye to be examined is assigned.

  The measurement mark forming means (for example, the display 36) may form a single measurement mark on the eye E as the measurement mark in the first eye position detection mode. In addition, the measurement mark forming means (for example, the display 36) has a second measurement position formed in a position different from the first measurement mark and the first measurement mark in the second eye position detection mode. And two measurement marks including the mark may be formed simultaneously. Further, the measurement mark forming means (for example, the display 36) may form the measurement mark in 0.5 mm steps in each of the first eye position detection mode and the second eye position detection mode.

  Further, the measurement mark moving means (for example, the controller 70) may move the measurement mark in 0.5 mm steps in the first eye position detection mode and the second eye position detection mode.

  From the above, the measurement mark forming means forms a single measurement mark as the measurement mark on the eye to be examined in the first eye position detection mode, and in the second eye position detection mode, Two measurement marks including one measurement mark and a second measurement mark formed at a position different from the first measurement mark are formed at the same time. In the eye position detection mode and the second eye position detection mode, a measurement mark can be formed in steps of 0.5 mm, and the measurement mark moving means includes the first eye position detection mode and the second eye position detection. It can be said that the measurement mark can be moved in 0.5 mm steps in each mode.

  In the above description, the first measurement mark M and the first measurement mark M and the second measurement are displayed each time the movement buttons 22R and 22L or the movement buttons 23R and 23L are pressed. However, the present invention is not limited to this. For example, in the right eye measurement mode, when one of the movement buttons 22R or 22L is continuously operated, the measurement mark M is moved by one segment in the input direction. Then, when the other button is operated, the second measurement mark Ms may be displayed in the segment adjacent to the segment in which the measurement mark M was displayed before the operation.

  For example, when measuring the right eye of the subject, it is assumed that there is a measurement mark M on the left side of the corneal bright spot. The examiner presses the measurement mark moving button 22R to move the measurement mark M to the right side. Assume that the measurement mark M is displayed in the segment c adjacent to the left of the corneal bright spot Q (see FIG. 6C). When the examiner presses the measurement mark moving button 22R again, the measurement mark M is displayed on the segment e adjacent to the right of the corneal bright spot Q (see FIG. 7B). Therefore, the examiner presses the measurement mark moving button 22L. Then, the control unit 70 displays the second measurement mark Ms on the segment d while displaying the measurement mark M on the segment e. Then, the control unit 70 may calculate the interpupillary distance using the value between the segment d and the segment e as the position of the pupil.

  Thus, the method for moving the measurement mark is not limited to the method of this embodiment. It is preferable to set the measurement mark moving method that is easy for the examiner to measure.

  The first measurement mark M and the second measurement mark Ms are displayed at the same time, and the position of the pupil is determined from the formation positions of the two measurement marks M and Ms. However, the present invention is not limited to this. Absent. For example, the position of the pupil may be obtained based on different formation positions of the measurement marks. For example, the examiner presses a recording button (not shown) with the measurement mark M displayed on the segment a. When the record button is pressed, the control unit 70 stores in the memory that the measurement mark M is displayed in the segment a. Thereafter, the examiner presses the movement buttons 22R and 22K or the movement buttons 23R and 23L to move the measurement mark M to the segment b. When the measurement mark M is displayed on the segment b by the control unit 70, the examiner presses the recording button again. When the recording button is pressed for the second time, the control unit 70 reads the information of the segment a stored in the memory 72 for the first time. Then, the control unit 70 sets an intermediate value as the pupil position from the positions of the segment a and the segment b, and obtains the inter-pupil distance. Alternatively, the average value of the measurement value obtained from the position of the segment a first stored in the memory 72 and the measurement value obtained from the position of the segment b may be used as the interpupillary distance. As described above, the two measurement marks need not be displayed simultaneously.

  In this embodiment, when the measurement mark is moved, the movement buttons 22R, 22L and the like are operated. However, the present invention is not limited to this. For example, the measurement mark M may be moved by operating a knob that is linked to a linear potentiometer (not shown). Such a configuration is described in detail in Patent Document 1 and Patent Document 2.

  In order to make it easier to confirm the positional relationship between the measurement mark M and the corneal bright spot, the control unit 70 may cause the measurement mark M to blink. Thereby, even when the corneal luminescent spot overlaps the measurement mark M, the position of the corneal luminescent spot can be visually recognized.

DESCRIPTION OF SYMBOLS 1 Interpupillary distance system 2 Case 3 Forehead support 4 Nose pad 21 Power button 24 Measurement mode switching button 25 Working distance change button 30 Measurement optical system 31 Light source for fixation target illumination 32 Fixation target 36 Liquid crystal display 70 Control part 72 Memory

Claims (3)

An interpupillary distance meter that measures the interpupillary distance of the subject by detecting the position of the subject eye in both the left and right eyes,
Irradiating means for irradiating light toward the eye to be examined through an examination window;
A measurement mark forming unit disposed between the eye to be examined and a fixation target, and forming a measurement mark on the eye to be examined, wherein the first measurement mark and the first measurement mark are used as the measurement mark. forming two measurement marks, the first measuring mark or the second and the measurement marks common display area and a second measurement mark formed on measuring mark different from the position of 1 A single measurement mark, and a measurement mark forming means for forming
Measurement mark moving means for moving the formation position of the measurement mark with respect to a cornea reflection image formed on the cornea of the eye to be examined by light from the irradiation means;
Detection mode switching means for switching between the first eye position detection mode and the second eye position detection mode;
In the first position detection mode, the position of the eye to be examined is detected based on a single formation position by the single measurement mark aligned with the cornea reflection image, and the second position in the detection mode, a first forming position by the first measuring mark which is aligned with respect to the cornea reflection image, the first forming position is aligned with respect to the cornea reflection image at different positions said second based on a second forming position of the measurement mark, eye position detecting means for detecting a position of the subject's eye was,
An interpupillary distance meter characterized by comprising: The interpupillary distance meter of claim 1,
In the second position detection mode, the measurement mark forming means simultaneously uses two measurement marks including the first measurement mark and the second measurement mark as the measurement marks. An interpupillary distance meter characterized by forming. In the interpupillary distance meter according to claim 1 or 2,
A detection mode switching means switches between the first eye position detection mode and the second eye position detection mode alternately.