JPH10111215A - Apparatus and method for measuring afocal optical system with display mark - Google Patents

Abstract

(57) [Problem] To provide a measuring device and a measuring method of an afocal lens with a display mark capable of eliminating uncertain factors such as individual differences of a measurer, visual acuity, skill, and the like, and measuring diopter with high accuracy. . SOLUTION: A first light source device 19 irradiates a slit 15a to form an image of the slit 15a on a light receiving element 37,
The output of the light receiving element 37 is amplified by the amplifier 53,
The diopter is differentiated by 5, and the diopter is obtained by setting the position where the peak value of the differential value becomes the maximum as the imaging position. The first light source device 19 is replaced with the second light source device 45, the image of the display mark provided on the subject A is formed on the light receiving element 37, and the position where the peak value of the differential value becomes maximum is obtained. The diopter of the display mark is obtained from the position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring the diopter of a lens and a display mark, and more particularly to an afocal optical system with a display mark used in a camera finder, binoculars, or a telescope. The present invention relates to a technique suitable for diopter measurement.

[0002]

2. Description of the Related Art In an afocal optical system such as a finder of a camera, a diopter telescope as shown in FIG. The diopter telescope 1 shown in FIG. 1 has an objective lens 2 fixed to an objective lens frame 3 and an eyepiece 4 fixed to an eyepiece lens frame 5, and these are fitted from both ends of a lens barrel 6. Objective lens frame 3 and eyepiece lens frame 5
Are both rotatable about the optical axis, and the objective lens 2 and the eyepiece 4 can advance and retreat on the optical axis by rotating. A diopter scale 3a is engraved on the outer periphery of the objective lens frame 3 as shown in FIG. In the middle of the inside of the lens barrel 6, there is a focusing screen 7, which has a scale such as a crosshair. The afocal optical system as the subject A is placed in front of the objective lens 2 of the diopter telescope 1.

When measuring the subject A, first, the eyepiece frame 5 is rotated while the subject A is not placed (although the subject may be present), and the scale drawn on the reticle 7 is displayed. The position of the eyepiece 4 on the optical axis is adjusted so that the eyepiece 4 can be clearly seen. Next, the subject A is arranged at the position shown in the figure, the objective lens frame 3 is brought into contact with the eyepiece thereof, and the objective lens frame 3 is rotated in a direction to separate the subject lens frame 3 from the subject A. The distant subject is adjusted so as to be clearly seen, and the diopter scale 3a at that time is read.

When the objective lens frame 3 is rotated so that the display mark drawn in the finder visual field of the subject A can be seen most clearly, and the diopter scale 3a when the image is clearly seen is read, the display mark of the display mark can be obtained. Diopter can be measured. Further, when measuring the diopter of the display mark at the periphery of the finder visual field or at the periphery of the visual field, the diopter is measured in the same manner as above by tilting the optical axis of the diopter telescope 1 with respect to the finder optical axis. Can be.

[0005]

However, in the above-mentioned method, since the measurer adjusts the focus visually, the influence of the measurement error by the measurer is large, and the measurement accuracy cannot be improved. In addition, there is also a problem that the measurement accuracy is reduced from this point, because the variation due to the eyesight difference of the measurer is large.

Further, when measuring the peripheral part of the visual field, the diopter telescope 1 is measured by tilting the diopter telescope 1 with respect to the optical axis of the subject A. However, the setting is unstable, and the measuring accuracy is further reduced. However, there is also a problem that the reproducibility is only about ± 0.2 dioptry.

The present invention has been made in view of the above facts. The present invention provides an afocal lens with a display mark which can eliminate uncertain factors such as individual differences of a measurer, visual acuity and skill, and can measure a diopter with high accuracy. It is an object to provide a measuring device and a measuring method. It is another object of the present invention to provide a measuring method and apparatus capable of stably and accurately measuring a peripheral portion of a visual field.

[0008]

In order to achieve the above-mentioned object, a lens measuring apparatus according to the present invention comprises a first light source, a pattern plate irradiated with light from the back by the first light source, and a pattern plate so that the pattern plate comes to a focal point. First having a collimator disposed therein
A light source device, a second light source device having a second light source and replaceable with the first light source device, and a display as an object such that light beams from the first or second light source device are selectively incident. A sample stage for holding a marked afocal optical system, an imaging lens system to which a light beam passing through the subject enters, and an image and display mark on the pattern plate that are movable in the optical axis direction of the imaging lens system And a differentiating circuit for differentiating the output of the light receiving element.

The first and second light source devices are movable in the y-axis direction perpendicular to the optical axis of the subject with the optical axis being the x-axis, and are rotatable in the xy plane. The imaging lens system and the light receiving element may be integrally movable in the y-axis direction and rotatable in the xy plane.

In this configuration, the sample stage is provided on an X stage extending in the x-axis direction of the subject, and the first light source device and the second light source device are rotatably mounted on a rotary stage. A structure movably engaged on a Y stage orthogonal to the X stage, wherein the imaging lens system and the light receiving element are integrated as an imaging unit, and movably provided on an arc-shaped stage protruding from the X stage. It is desirable to do. A configuration in which the pattern plate has a slit, a configuration in which the second light source device has a diffusion plate on an irradiation surface, and a configuration in which the light receiving element is a line sensor can be employed.

According to the measuring method of the present invention, light from a light source is transmitted through a pattern plate, the transmitted light is converted into a parallel light by a collimator, and the parallel light is transmitted through an afocal optical system with a display mark as an object. Incident on the imaging lens,
Forming the pattern image of the pattern plate on the light receiving element by the imaging lens, differentiating the output of the light receiving element, and measuring the diopter with the position where the peak value of the differential value becomes the maximum as the image forming position. Features.

Alternatively, light from a light source is irradiated to an afocal optical system having a display mark as an object, and an image of a display mark provided on the object is formed on a light receiving element by an imaging lens. The output is differentiated, and the diopter of the display mark is determined by using the position where the peak value of the differential value becomes the maximum as the imaging position of the display mark.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of one embodiment of the measuring device of the present invention. The light source 11 is supported by the cylindrical body 13,
A pattern plate 15 and a collimator lens 17 are integrally incorporated in the cylindrical body 13, and the whole constitutes a first light source device 19. A slit 15 a is formed in the pattern plate 15, and the slit 15 a overlaps a front focal point of the collimator lens 17. The cylindrical body 13 is fixed to a rotary stage 21, and the rotary stage 21 is movably engaged with a Y stage 23 extending in the y-axis direction. An angle scale is engraved on the rotary stage 21, and a scale indicating the distance is engraved on the Y stage 23, so that the distance and the angle in the Y direction to which the first light source device 19 has moved can be read.

The center of the Y stage 23 is orthogonal to the X stage 25, and a sample table 27 is provided near the center of the X stage 25, and the subject A is removably mounted on the sample stage 27. The subject A in this embodiment is a finder lens of a camera, and is an afocal optical system having a display mark such as a finder frame. The optical axis a of the subject A is X
It matches the center of stage 25.

On the right side of the sample stage 27 of the X stage, there is an imaging unit 29, in which a field stop 31, an imaging lens 33,
A magnifying lens 35 and a light receiving element 37 composed of a CCD line sensor are attached. An imaging lens system 39 is constituted by the imaging lens 33 and the magnifying lens 35. Also, the magnifying lens 35 and the light receiving element 37 among the above are connected to the light receiving section 4.
1 is a configuration in which focusing can be performed by integrally moving forward and backward in the optical axis direction. The imaging unit 29 is also movable on an arc-shaped stage 43 that protrudes in an arc shape from the X stage 25, and at this time, moves so as to rotate around the field stop 31. The arc-shaped stage 43 also has a scale, so that the angle of the imaging unit 29 can be read.

Below the first light source device 19 of the Y stage 23, a second light source device 45 is provided. The second light source device includes a light source 47 formed by bundling a large number of fibers in parallel, and a diffusion plate 49.
And is rotatable in the xy plane (around the z-axis), and is movable on the Y stage by the engagement of the rotary stage 51 and the Y stage 23. Rotation stage 51
Is provided with an angle scale, so that the moving distance and angle of the second light source device 45 can be easily known.

The output of the light receiving element 37 is amplified by an amplifier 53 and then differentiated by a differentiating circuit 55. The processed signal is processed by the computer 57, and the output of the light receiving element 37 and the waveform of the differential value are displayed on the display 59.

In FIG. 1, a light beam emitted from the light source 11 and transmitted through the slit 15a of the pattern plate 15 is converted into a parallel light beam by the collimator lens 17, passes through the subject A, passes through the field stop 31, and then forms an imaging lens. The image becomes a real image at 33 and is further enlarged by the magnifying lens 35 to form a slit image on the light receiving element 37.

FIG. 2A is a view showing a slit image 16 formed so as to be orthogonal to the light receiving element 37. Light receiving element 3
7 has a large number of elements arranged. When the output of each element corresponding to the slit image 16 is shown in a graph, the output becomes a diagram as shown in FIG. When this output is differentiated by the differentiating circuit 55, a diagram as shown in FIG. 2C is obtained. The computer 57 detects this peak value H, and the light receiving element 3 at which H is maximized
By detecting the position 7, the diopter when the subject is at infinity can be obtained.

As described above, according to the present invention, the detection of the image formation position can be performed by the numerical value of <detection of the peak value of the differential value>. Measurements can be made without such factors. In addition, the reproducibility was about ± 0.05 dioptry, which was much higher than the conventional one.

Next, the measurement of the diopter of the display mark provided in the finder field will be described. First, in FIG. 1, the first light source device 19 is moved upward in the drawing, and instead, the second light source device 45 is moved to a position where the first light source device 19 was located. Light source 47 made of fiber of second light source device 45
Emits a substantially parallel light beam, and irradiates the subject A via the diffusion plate 49. When the light receiving unit 41 is moved in the optical axis direction, an image of a display mark (for example, a finder frame) drawn on the subject A is formed on the light receiving element 37.

FIG. 3A shows a display mark image 50 formed on the light receiving element 37. Although the slit image 16 in FIG. 2 is a bright image, the image of the display mark is a dark image, and the output of the light receiving element 37 is in the opposite direction (minus) to that in FIG.
Output. After the output is amplified by the amplifier 53 and differentiated by the differentiating circuit 55 and the position at which the peak value H is maximized is determined by the computer 57, the diopter of the display mark can be determined.

FIG. 4 is a diagram for explaining a method of measuring off-axis diopter. First, the first light source device 19 is connected to the Y stage 23.
At the same time as moving up, it is rotated in the xy plane so that the light beam emitted from the collimator lens 17 is adjusted to enter the subject A. The moving distance of the first light source device 19 is read from the scale of the Y stage 23, and the angle is read from the scale of the rotary stage 21. Next, the imaging unit 29 is moved on the arc-shaped stage 43 so that the light beam emitted from the subject A can be received. That is, the imaging unit 41 moves in the y-axis direction,
In addition, it rotates in the xy plane. The angle after the movement can be read from the scale of the arc stage.
The moving distance of the imaging unit 29 in the y-axis direction can be obtained by calculation. Next, the light receiving unit 41 is advanced and retracted along the optical axis, and adjustment is performed so that the image of the slit 15a is formed on the light receiving element 37. The following is the same as the on-axis measurement described above.

After that, the first light source device 19 is moved, and then the second light source device 45 is installed. If the same operation is performed, the diopter can be measured in an off-axis visual field. The moving distance and the angle of the second light source device are obtained in the same manner as in the first light source device. In the above embodiment, the light receiving element 37 is a line sensor, but an area sensor may be used. When an area sensor is used, the same measurement can be performed by reading the output of the light receiving element 24 in a direction crossing the slit image or the display mark image. CCD as line sensor
A linear sensor, a photodiode array, or the like can be used. In the above embodiment, the slit 15a is used as the pattern plate, but a shape other than the slit may be used.

[0025]

According to the present invention as described above,
The light image of the pattern plate illuminated by the light source passes through the test lens and the imaging lens, is measured by the light receiving element, is differentiated by the differentiating circuit, and the position of the light receiving element at which the peak value of the differential value reaches the maximum value is determined. Since the diopter of the sample is measured, the diopter of the subject can be measured with high accuracy.

Also, the diopter at infinity and the diopter of the display mark are measured by the first light source device and the second light source device, respectively.
Measurement can be performed easily. The first and second light source devices are movable in a y-axis direction orthogonal to the optical axis of the subject as an x-axis, and are rotatable in the xy plane. And the light receiving element are integrally movable in the y-axis direction and rotatable in the xy plane, so that not only on-axis diopter measurement but also off-axis diopter measurement can be performed.

X extending in the x-axis direction of the subject through the sample stage
The first light source device and the second light source device are rotatably mounted on a rotary stage, and each rotary stage is movably engaged on a Y stage orthogonal to the X stage; If the lens system and the light receiving element are integrated as an imaging unit and are movably provided on an arc-shaped stage protruding from the X stage, off-axis measurement can be stably performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a measuring device of the present invention.

2A is a diagram showing a relationship between a light receiving element and a slit image, FIG. 2B is a diagram showing an output of the light receiving device, and FIG. 2C is a diagram showing a differential of the output of the light receiving device.

3A is a diagram showing a relationship between a light receiving element and a display mark image, FIG. 3B is a diagram showing an output of the light receiving device, and FIG. 3C is a diagram showing a differentiated output of the light receiving device.

FIG. 4 is a diagram illustrating a method of measuring off-axis diopter.

FIG. 5A is a diagram showing a configuration of a conventional diopter measurement device;
(B) is a partial view as viewed from arrow B in (a).

[Explanation of symbols]

 A lens under test 11 first light source 15 pattern plate 15a slit 17 collimator 19 first light source device 21 rotation stage 23 Y stage 25 X stage 27 sample table 29 imaging unit 37 light receiving element 39 imaging lens system 45 second light source device 47 Second light source 49 Diffuser 55 Differentiation circuit

Claims (8)

[Claims] A first light source device having a first light source, a pattern plate irradiated with light from the back thereof, and a collimator arranged so that the pattern plate comes to a focal point;
A second light source device having a light source and being replaceable with the first light source device, and an afocal optical system with a display mark as a subject so that a light beam from the first or second light source device is selectively incident. And an imaging lens system on which a light beam passing through the subject enters, and movable in the optical axis direction of the imaging lens system so as to intersect the image of the pattern plate and the image of the display mark. A measuring device for an afocal optical system with a display mark, comprising: a light-receiving element disposed in the light-receiving element; and a differentiating circuit for differentiating an output of the light-receiving element. 2. The apparatus according to claim 1, wherein the first and second light source devices are movable in a y-axis direction orthogonal to an optical axis of the subject as an x-axis, and rotatable in the xy plane. 2. The measurement of an afocal optical system with a display mark according to claim 1, wherein the imaging lens system and the light receiving element are integrally movable in the y-axis direction and rotatable in the xy plane. apparatus. 3. The sample stage is provided on an X stage extending in the x-axis direction of the subject. The first light source device and the second light source device are rotatably mounted on a rotary stage, and each rotary stage is mounted on the X stage. The imaging lens system and the light receiving element are movably engaged on a Y stage orthogonal to the stage, and the imaging lens system and the light receiving element are integrated as an imaging unit and provided movably on an arc-shaped stage protruding from the X stage. The measuring device for an afocal optical system with a display mark according to claim 2. 4. The measuring device for an afocal optical system with a display mark according to claim 1, wherein the pattern plate has a slit. 5. The measuring device for an afocal optical system with a display mark according to claim 1, wherein the second light source device has a diffusion plate on an irradiation surface. 6. The measuring device for an afocal optical system with a display mark according to claim 1, wherein the light receiving element is a line sensor. 7. A light from a light source is transmitted through a pattern plate, the transmitted light is converted into a parallel light by a collimator, and the parallel light is transmitted through an afocal optical system with a display mark as an object to be incident on an imaging lens. To form a pattern image of the pattern plate on the light receiving element by the imaging lens,
A method for measuring an afocal optical system with a display mark, comprising differentiating an output of a light receiving element and measuring a diopter with a position at which a peak value of a differential value becomes a maximum as an image forming position. 8. A light from a light source is irradiated to an afocal optical system with a display mark as a subject, and an image of a display mark provided on the subject is formed on a light receiving element by an imaging lens. A method for measuring an afocal optical system with a display mark, wherein the output is differentiated, and the position at which the peak value of the differential value is maximized is determined as the imaging position of the display mark to determine the diopter of the display mark.