JP6398385B2 - 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 positional relationship between the optical axis of the lens and the pupil of the corresponding eyeball must be adjusted based on a gaze distance (this is also referred to as a working distance) in an average use state. For this purpose, it is necessary to measure the interpupillary distance of the eyeball of the subject.

  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) formed near the examination window, An interpupillary distance meter that measures the interpupillary distance is known (see, for example, Patent Document 1).

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

  However, in the conventional apparatus, the examiner sometimes has difficulty in confirming that the position of the measurement mark has reached the limit of the measurement range.

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

  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 the subject based on the positions of the left and right eye to be examined, which is disposed in front of the eye to be examined and is arranged through the right and left examination windows. Display means for displaying the measurement mark for each of the left and right, a movement button for outputting an operation signal according to the operation of the examiner, and an operation signal output by pressing the movement button by the examiner The display of the display means is controlled based on the first display for moving the display position of the measurement mark in the left-right direction at a predetermined pitch in a measurement movement range determined from a preset measurement range with respect to the eye to be examined. Display control means for executing control, and calculation means for calculating the distance between the pupils of the subject based on the display position of the measurement mark, wherein the display control means includes the measurement mark as the measurement mark. Measurement movement When the left or right limit of the range is reached, the second display control different from the first display control is executed.

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. An example of the measurement result of the interpupillary distance displayed on the display unit is shown. It is a figure explaining the conversion method of the distance between pupils. It is a figure explaining the 2nd display control when the mark for measurement reaches the movement limit. It is a flowchart which shows an example of the control method of a present Example.

<Overview>
The outline of the first embodiment will be described below. In the following description, the same components are described with the same numbers. The interpupillary distance meter 1 of the first embodiment measures the interpupillary distance of the subject based on the positions of the left and right eye E, for example.

  The interpupillary distance meter 1 (see FIG. 1) mainly includes, for example, a measurement mark moving unit, a calculation unit, and a display control unit (see FIGS. 3 and 4). The control unit 70 may also serve as a measurement mark moving unit, a calculation unit, a display control unit, and the like. Of course, a configuration in which a measurement mark moving unit, a calculation unit, and a display control unit are provided separately may be employed.

  The measurement mark moving unit moves the formation positions of the measurement marks formed on the left and right sides (for example, displayed) with respect to the eye E through the left and right examination windows 6. For example, the calculation unit calculates the interpupillary distance of the subject based on the formation position of the measurement mark M aligned with the eye E. The display control unit displays the calculation result of the interpupillary distance calculated by the calculation unit on the result display unit 7 at an interval (display pitch) smaller than 0.5 mm. As a result, the examiner can obtain a good interpupillary distance for making and fitting spectacles.

  The display control unit may display the calculation result of the interpupillary distance calculated by the calculation unit on the result display unit 7 at intervals of 0.5 mm and intervals smaller than 0.5 mm. For example, the calculation result of the interpupillary distance may be simultaneously displayed on the result display unit 7 at intervals of 0.5 mm and intervals smaller than 0.5 mm.

  The interpupillary distance meter 1 may further include an output mode switching unit (for example, the control unit 70). The output mode switching unit may switch the calculation result of the interpupillary distance calculated by the calculation unit between the first output mode and the second output mode. The first output mode is an output mode in which, for example, the calculation result of the interpupillary distance calculated by the calculation unit is output to the result display unit 7 at intervals of 0.5 mm. The second output mode is an output mode in which, for example, the calculation result of the interpupillary distance calculated by the calculation unit is output to the result display unit 7 at an interval smaller than 0.5 mm. In this case, the display control unit may display the calculation result on the result display unit 7 at intervals corresponding to the output mode switched by the output mode switching unit. Thus, the examiner can switch the display interval of the interpupillary distance to be output to the result display unit 7 according to the purpose of use of the interpupillary distance.

  Note that the second output mode may be, for example, an output mode in which the calculation result of the interpupillary distance is output to the result display unit 7 at intervals of 0.1 mm. The display at intervals of 0.1 mm is finer than the intervals of 0.5 mm, and is easy to handle as numerical values, for example.

  Note that the output mode switching unit may include a changeover switch (for example, a measurement mode switching button 24). For example, the changeover switch may be operated by an examiner to switch between the first output mode and the second output mode. In this case, the output mode switching unit may switch between the first output mode and the second output mode based on the output from the changeover switch according to the operation of the examiner.

  The outline of the second embodiment will be described below. The same components as those in the first embodiment will be described with the same numbers. The interpupillary distance meter 1 of the second embodiment measures the interpupillary distance of the subject based on the positions of the left and right eye E, for example.

  The interpupillary distance meter 1 (see FIG. 1) mainly includes, for example, a display unit (for example, the display 36), a calculation unit, and a display control unit (see FIGS. 3 and 4). Note that the control unit 70 may also serve as a calculation unit, a display control unit, and the like. Of course, it is good also as a structure by which a calculating part and a display control part are each provided separately.

  For example, the display unit is arranged in front of the eye E and displays the measurement marks M on the left and right sides of the eye E via the left and right examination windows 6. The calculation unit calculates the interpupillary distance of the subject based on the display position of the measurement mark M.

  For example, the display control unit may control the display of the display unit based on an operation signal output from the operation unit (for example, the movement buttons 22 and 23) according to the operation of the examiner. For example, the display control unit may execute the first display control. For example, the first display control may be display control for moving the display position of the measurement mark M in the left-right direction at a predetermined pitch with respect to the eye E in the measurement movement range (for example, the display area Ac). Good.

  The measurement movement range is, for example, the movement range of the measurement mark M, and may be determined from a preset measurement range. The measurement range set in advance is, for example, the measurement range of the interpupillary distance set in consideration of individual differences in the assumed interpupillary distance. For example, the measurement range of the interpupillary distance may be preset in a range of 40 to 90 mm. Of course, the specific numerical setting is not limited to this, and can be set as appropriate. Note that the measurement mark M may be displayable outside the measurement movement range (for example, between display areas Ac-Al, between display areas Ac-Ar, display areas Al, Ar, etc.).

  For example, when the measurement mark reaches the left or right limit of the measurement movement range, the display control unit executes the second display control different from the first display control. The second display control may be, for example, display control for turning on, blinking, or turning off a part or all of the display area of the display unit, or display control for blinking or turning off the measurement mark M. Also good. The second display control is preferably display control that allows the examiner observing the display unit to distinguish from the first display control.

  As described above, the interpupillary distance meter 1 of the second embodiment changes the display on the display unit when the measurement mark M reaches the limit of the measurement movement range. Thereby, the examiner can confirm that the measurement mark M has reached the limit of the measurement movement range.

  The operation unit moves the measurement mark M to the left with respect to the eye E based on the operation of the examiner, and the right movement signal with respect to the eye E to move the measurement mark M to the right. A right movement signal for movement may be output. In this case, the display control unit may execute the second display control either when the measurement mark M reaches the leftward movement limit or when the measurement mark M reaches the rightward movement limit. For example, when the examiner moves the measurement mark M to the left or right by operating the operation unit, the measurement mark M is either left or right of the measurement movement range by checking the change in the display on the display unit. It can be confirmed that the limit has been reached.

  Note that the display control unit outputs a left movement signal from the operation unit when the measurement mark M reaches the leftward movement limit (for example, the segment Sa), or the measurement mark M moves to the rightward movement limit (for example, the segment Sa). The second display control may be executed in any of the cases where the right movement signal is output from the operation unit when reaching the segment Sl).

<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 E with illumination light to form a bright spot at the apex of the cornea. This bright spot is a virtual image (corneal reflection image) of illumination light, and is formed at the position of the apex of the cornea. 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. 2), and a result display unit 7. On the housing 2, a power button 21, a move button 22, a move button 23, a measurement mode switching button 24, a work distance change button 25, and the like are arranged. The movement button 22 includes, for example, a left movement button 22L and a right movement button 22R. The movement button 22 is used to move a measurement mark M, which will be described later, displayed on the right eye side of the subject to the left and right. The movement button 23 includes, for example, a left movement button 23L and a right movement button 23R. The movement button 23 is used to move a measurement mark M (described later) displayed on the left eye side of the subject to the left and right. For example, when the right movement buttons 22R and 23R are pressed, a right movement signal for moving the measurement mark M to the right side of the examiner is output to the control unit 70. For example, when the left movement buttons 22L and 23L are pressed, a left movement signal for moving the measurement mark M to the left side of the examiner is output to the control unit 70. 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. In the right eye measurement mode, the distance (one-eye pupil distance) from the pupil of the subject's right eye to the central axis O1 passing through the mechanical center of the interpupillary distance meter 1 is measured. In the left eye measurement mode, the distance (one-eye pupil distance) from the pupil of the left eye of the subject to the central axis O1 passing through the center of the interpupillary distance meter 1 is measured. 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 central axis O1 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 result 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 (display means) 36. Prepare.

  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.

  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 (for example, displays) a measurement mark M described later.

  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, for example, photoetching a glass coated with a transparent metal coat. However, it may not be a segment type liquid crystal display, and for example, a matrix type liquid crystal display may be used. The segment type liquid crystal display 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.

  In this embodiment, the fixation target presentation distance (working distance) is fixed. In the distance meter 1, first, the interpupillary distance at a fixed work distance is obtained, and the interpupillary distance at a different work distance is obtained by calculation using this result. 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. The working distance Dm is unique to the distance meter 1 and is known. When the interpupillary distance at the working distance Dm is PDm and the interpupillary distance at the obtained working distance Dn is PDn, PDn is calculated by the following equation.

  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.

<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, a memory 72, and the like. The control unit 70 includes a result display unit 7, a power button 21, a movement button 22, a movement button 23, a measurement mode switching button 24, a work distance change button 25, a fixation target illumination light source 31, and a display. 36, the memory 72 and the like.

  FIG. 5 is a schematic view showing the display 36 used in this embodiment. The display 36 displays, for example, a linear measurement mark M extending in the vertical direction of the subject. For example, the display 36 has a large number of line-shaped segments arranged in the vertical direction. In FIG. 5, for convenience of explanation, each segment area is indicated by a dotted 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). For example, the control unit 70 may control the number, position, etc. of the segment to which the voltage is applied, and may calculate and output the interpupillary distance based on the segment number, position, etc. Note that the measurement mark M 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 result 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 setting change of the working distance may be performed 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 button 22 and the movement button 23 to move the measurement mark M so as to overlap the corneal bright spot P. The control unit 70 receives operation signals from the movement button 22 and the movement button 23 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 M formed on the display 36.

  For example, in the state shown in FIG. 5A, the examiner presses the right movement button 22R twice. The control unit 70 receives an operation signal from the right movement button 22R. The control unit 70 moves the display position of the measurement mark M displayed on the right eye side of the subject to the right side with respect to the subject eye E. For example, when the right movement button 22R is pressed once, the control unit 70 turns off the segment Se and turns on the segment Sf. When the right movement button 22R is pressed again, the control unit 70 turns off the segment Sf and turns on the segment Sg. From the state shown in FIG. 5A, when the right movement button 22R is pressed twice, the corneal bright spot P formed at the position of the segment Sg overlaps the measurement mark M. Thus, the examiner operates the movement button 22 to display the measurement mark M at a position overlapping the corneal bright spot P. Similarly, the examiner moves the measurement mark M to the position of the corneal bright spot P with respect to the left eye of the subject.

  The control unit 70 detects the display position of the measurement mark M as the position of the pupil of the eye to be examined, and calculates the interpupillary distance. For example, the control unit 70 calculates the interpupillary distance of the subject based on the formula (1). For example, the control unit 70 may read 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. Then, the control unit 70 may display the distance read from the memory 72 on the result display unit 7.

<Display method of calculation results>
Hereinafter, the display method of the measurement result in the interpupillary distance meter 1 of a present Example is demonstrated. The interpupillary distance meter 1 according to the present embodiment displays the measurement result on the result display unit 7 at a display pitch (display interval) of 0.5 mm, for example. Furthermore, the interpupillary distance meter 1 according to the present embodiment may display the measurement results at a display pitch finer than 0.5 mm. This makes it possible to finely adjust the glasses. Therefore, the production of the custom lens or the fitting of the spectacle frame is performed satisfactorily, and the performance of the spectacles can be fully exhibited.

  Furthermore, for example, the measurement result of the interpupillary distance may be displayed at a plurality of display pitches. Thereby, the examiner may acquire the measurement result of the interpupillary distance according to the purpose of use.

  For example, the interpupillary distance meter 1 of the present embodiment may be able to switch the display pitch of the measurement result of the interpupillary distance calculated by the equation (1) or the like. For example, the interpupillary distance meter 1 may switch the display pitch of the measurement result by selecting a display pitch when displaying the measurement result from a predetermined display pitch range. Furthermore, the interpupillary distance meter 1 may be able to switch the display pitch of the measurement results between a plurality of preset display pitches. More specifically, the interpupillary distance meter 1 may be switched to a display pitch selected from, for example, 0.1 mm to 0.5 mm, or by switching the display pitch between 0.1 mm and 0.5 mm, for example. Also good. Thus, it is preferable that the measurement result according to use conditions can be acquired by switching the display pitch.

  For example, it is preferable that the interpupillary distance for output to an eyeglass lens processing apparatus (not shown) is output at a fine pitch. On the other hand, the interpupillary distance used when performing visual acuity inspection using a temporary frame inspection or a reflector may not need to be output at a fine pitch. This is because, for example, when a temporary frame or a refractor is used, the degree of freedom of alignment with respect to the eye to be examined is high.

  Thus, since the interpupillary distance is used for various purposes, it is preferably output at a display pitch according to the purpose.

  In the case of the present embodiment, two types of output modes are used: a first output mode that displays measurement results at a display pitch of 0.1 mm, and a second output mode that displays measurement results at a display pitch of 0.5 mm. FIG. 6A shows an example of the result display unit 7 in the first output mode. FIG. 6B shows an example of the result display unit 7 in the second output mode. The interpupillary distance meter 1 of the present embodiment may switch between the first output mode and the second output mode, for example, by long pressing the measurement mode switching button 24. For example, the control unit 70 may switch the output mode of the result display unit 7 by receiving an output mode switching signal output when the measurement mode switching button 24 is long pressed.

<Conversion method>
Hereinafter, a method for converting the calculation result of the interpupillary distance so as to be suitable for the selected display pitch will be described. FIG. 7 shows an example of the calculated numerical value of the distance between the pupils of one eye.

  For example, FIG. 7A shows the conversion result when the calculation result of the interpupillary distance of one eye is converted when the display pitch is 0.1 mm. FIG. 7B shows the conversion result when the calculation result of the interpupillary distance of one eye is converted when the display pitch is 0.5 mm.

  In this embodiment, for example, the conversion is performed by rounding the calculation result of the interpupillary distance. Note that rounding is to replace a given numerical value with a numerical value selected from a series formed by an integer multiple of a certain rounding width. This replaced numerical value is called a rounded numerical value (see Japanese Industrial Standard JISZ8401 “How to Round Numbers”).

  As shown in FIG. 7A, for example, it is assumed that the calculation result of the interpupillary distance is 32.223, 32.281, 32.315. When displaying these calculation results at a display pitch of 0.1 mm, the control unit 70 rounds the numerical value with a rounding width of 0.1 mm, for example. For example, when 32.223 is rounded with a rounding width of 0.1 mm, 32.223 is a numerical value between 32.2 and 32.3. Further, 32.223 is smaller than 32.25, which is an intermediate value between 32.2 and 32.3. Therefore, 32.223 is a value closer to 32.2 than 32.3, and is rounded to 32.2. Similarly, 32.281 is rounded to 32.3 because it is greater than 32.25, which is an intermediate value between 32.2 and 32.3. Similarly, since 32.315 is larger than 32.25, which is an intermediate value between 32.2 and 32.3, it is rounded to 32.3.

  In addition, when displaying said calculation result by display pitch 0.5mm, the control part 70 rounds a numerical value with the rounding width 0.5mm, for example. For example, when 32.223 is rounded with a rounding width of 0.5 mm, 32.223 is a numerical value between 32.0 and 32.5. Furthermore, 32.223 is a value smaller than 32.25 which is an intermediate value between 32.0 and 32.5. Therefore, since 32.223 is a numerical value closer to 32.0 than 32.5, it is rounded to 32.0. Similarly, 32.281 is rounded to 32.5 because it is greater than 32.25, which is an intermediate value between 32.0 and 32.5. Similarly, since 32.315 is larger than 32.25, which is an intermediate value between 32.0 and 32.5, it is rounded to 32.5.

  As described above, the interpupillary distance suitable for each display pitch can be acquired by converting the calculation result of the interpupillary distance by a plurality of methods. Thereby, the interpupillary distance meter 1 of the present embodiment can output the interpupillary distance at a display pitch desired by the examiner. The rounding width is not limited to 0.5 and 0.1, but other values may be used, but are preferably 0.5 or less.

  In the above description, the display pitch of the measurement result can be switched and displayed. However, the present invention is not limited to this. For example, the measurement results may be simultaneously displayed on the result display unit 7 at a plurality of display pitches. In this case, the examiner may read only the numerical value output at a display pitch suitable for the purpose.

<Measurement mark movement limit display>
The interpupillary distance meter 1 of the present embodiment may change the display on the display 36 when the measurement mark M reaches the limit of the measurement movement range (corresponding to the display area Ac). Accordingly, the examiner may be notified that the measurement mark M has reached the limit of the measurement movement range. The measurement movement range is, for example, the movement range of the measurement mark M obtained from a preset measurement range. Therefore, the limit of the measurement movement range is a position where the measurement mark M is displayed when the maximum value or the minimum value of the interpupillary distance that can be measured by the interpupillary distance meter 1 is calculated. For example, in this embodiment, when the measurement mark M is formed by the segment Sa and the segment Sl, the measurement mark M has reached the limit of the measurement movement range.

  Hereinafter, in the present embodiment, display when the measurement mark M reaches the limit of the measurement movement range will be described. The interpupillary distance meter 1 of the present embodiment switches the display control of the display 36 from the first display control to the second display control when the measurement mark M reaches the limit of the measurement movement range. The first display control is, for example, a normal display in which the measurement mark M is displayed on the left and right eyes and the measurement mark M is moved left and right based on the operation signals from the movement buttons 22 and 23. Control. The second display control is display control different from the first display control, and is display control that can identify the limit of the measurement movement range. For example, the second display control is display control for blinking the display areas Ar and Al on both sides of the display area Ac. The second display control is not limited to the display control described above, and various methods can be considered (details will be described later).

  FIG. 8A shows a case where the measurement mark M has reached the right limit of the measurement movement range. Assume that the examiner presses the right movement button 22R in this state. The right movement signal output by operating the right movement button 22R is input to the control unit 70.

  When the control unit 70 receives a right movement signal in a state where the measurement mark M has reached the right limit of the measurement movement range, the control unit 70 blinks the display areas Ar and Al (see FIG. 8B).

  As described above, when the measurement mark M reaches the left or right limit of the measurement movement range, the control unit 70 receives the operation signal in the direction exceeding the measurement movement range, and performs the first display control of the display 36. The display control may be changed to the second display control. By switching the display on the display 36, the examiner can confirm that the measurement mark M cannot be moved further to the right or left.

  The processing as described above will be described with reference to the control flowchart shown in FIG. FIG. 9 is an example of a control flowchart relating to the movement limit display of the measurement mark M. In step 1 of FIG. 9, the control unit 70 acquires an operation signal (movement signal) output from the movement buttons 22 and 23. When the control unit 70 acquires the operation signal, the control unit 70 proceeds to Step 2.

  In step 2, for example, the control unit 70 proceeds to step 3 when the acquired operation signal is a right movement signal, and proceeds to step 4 when the operation signal is a left movement signal. The controller 70 determines that the operation signal is a left movement signal when the left movement buttons 22L and 23L are pressed, and the operation signal is a right movement signal when the right movement buttons 22R and 23R are pressed. It may be determined that there is.

  In step 3, the control unit 70 determines whether, for example, the display position of the measurement mark M is the right limit of the measurement movement range. For example, in this embodiment, when the measurement mark M is displayed in the segment Sl, the control unit 70 determines that the measurement mark M is the limit on the right side of the measurement movement range. The control unit 70 proceeds to step 5 when the display position of the measurement mark M is the limit on the right side of the measurement movement range, and proceeds to step 6 when it is not the limit.

  In step 4, the control unit 70 determines whether, for example, the display position of the measurement mark M is the left limit of the measurement movement range. For example, in this embodiment, when the measurement mark M is displayed in the segment Sa, the control unit 70 determines that the measurement mark M is the left limit of the measurement movement range. The control unit 70 proceeds to step 5 when the display position of the measurement mark M is the limit on the left side of the measurement movement range, and proceeds to step 7 when it is not the limit.

  In step 5, the control unit 70 performs second display control. For example, the control unit 70 causes the display area areas Al and Ar of the display 36 to blink. Thus, the examiner can confirm that the measurement mark M has reached the right movement limit. The control unit 70 ends this process when the second display control is performed.

  In step 6, the control unit 70 performs the first display control. For example, the control unit 70 moves the display position of the measurement mark M to the right, and ends this process.

  In step 7, the control unit 70 performs the first display control. For example, the control unit 70 moves the display position of the measurement mark M to the left, and ends this process.

  As described above, the interpupillary distance meter 1 according to the present embodiment changes the display control of the display 36 when the display position of the measurement mark M reaches the limit of the measurement movement range. Thus, the examiner can confirm that the display position of the measurement mark M has reached the limit of the measurement movement range.

  For example, when the movement of an operation member such as a knob is detected by a linear potentiometer or the like as in the prior art, the movement limit of the measurement mark M confirms the physical operation range of the operation member and the movement limit of the measurement mark M. be able to. However, as in the present embodiment, when an instruction to move the measurement mark M is received by the movement buttons 22 and 23, it is difficult for the examiner to confirm whether or not the measurement mark M has reached the movement limit. Therefore, the movement buttons 22 and 23 may be pushed by the examiner even though the measurement mark M reaches the limit of the measurement movement range. In addition, the fact that the measurement mark M does not move due to the movement limit may be misunderstood as a failure of the interpupillary distance meter 1. The interpupillary distance meter 1 according to the present embodiment can confirm that the display position of the measurement mark M has reached the limit of the measurement movement range, and thus can reduce erroneous operations as described above. The control flow in FIG. 9 is an example, and control may be performed by another control flow.

  The control unit 70 may change the display control of the display 36 when the measurement mark M reaches the limit of the measurement movement range even when there is no operation signal from the movement buttons 22 and 23. Good.

  In the above description, the second display control is assumed to blink the display areas Al and Ar, for example, but is not limited thereto. For example, the second display control may be display control that can identify that the movement position of the measurement mark M has reached the limit of the measurement movement range. For example, the second display control may be control for lighting the display areas Al and Ar. For example, the second display control may be a control for blinking (or turning on or off) one of the display areas Al and Ar. For example, the second display control may be control for blinking (or lighting or extinguishing) a part of the area of the display 36, or control for blinking (or lighting or extinguishing) all the areas of the display 36. For example, the second display control may be a control for blinking (or turning off) the measurement mark M.

  In this embodiment, when the measurement mark M is moved, the movement buttons 22, 22 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 Patent Document 1 and Patent Document 2.

DESCRIPTION OF SYMBOLS 1 Interpupillary distance meter 2 Body 3 Forehead support 4 Nose pad 21 Power button 22 Move button 23 Move button 24 Measurement mode switch button 25 Working distance change button 30 Measurement optical system 31 Light source for fixation target illumination 32 Fixation target 36 Display 70 Control unit 72 Memory

Claims (5)

An interpupillary distance meter that measures the interpupillary distance of the subject based on the positions of the left and right eye;
Display means arranged in front of the eye to be examined and displaying a measurement mark on each of the left and right sides of the eye to be examined through left and right examination windows;
A movement button for outputting an operation signal according to the operation of the examiner;
The display of the display means is controlled based on an operation signal output when the movement button is pressed by the examiner, and the measurement is performed in a measurement movement range determined from a preset measurement range for the eye to be examined. Display control means for executing first display control for moving the display position of the mark in the left-right direction at a predetermined pitch;
A calculation means for calculating the distance between the pupils of the subject based on the display position of the measurement mark;
The interpupillary distance meter, wherein the display control means executes a second display control different from the first display control when the measurement mark reaches a left or right limit of the measurement movement range. The operation means moves the measurement mark in the left direction with respect to the eye to be examined based on the operation of the examiner, and moves the measurement mark in the right direction with respect to the eye to be examined. To output a right movement signal for
The display control means includes
When the measurement mark reaches the left movement limit,
2. The interpupillary distance meter according to claim 1, wherein the second display control is executed when the measurement mark reaches the rightward movement limit. The display control means includes
When the measurement mark reaches the left movement limit, and the left movement signal is output from the operation means,
The second display control is performed when the measurement mark reaches a rightward movement limit and the rightward movement signal is output from the operation unit. 2 interpupillary distance meter.   The second display control is display control for lighting, blinking, or extinguishing a part or all of a display area of the display unit that is different from a display position of the measurement mark. The interpupillary distance meter according to any one of Items 1 to 3.   The interpupillary distance meter according to any one of claims 1 to 3, wherein the second display control is display control for blinking or turning off the measurement mark.

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