JPH0329812A - Inspecting device of distance measuring apparatus - Google Patents

Abstract

PURPOSE:To reduce a space for inspection of a distance measuring apparatus by shortening an optical path by interposing an angle-deflecting prism mechanism in the direction of light projection of a projecting element, and by lessening the quantity of light to be sensed by a light-sensing element by controlling properly the quantity of light transmitted through the optical path from the projecting element to the light- sensing element. CONSTITUTION:When inspection is made as to whether a distance measuring apparatus 1 operates correctly or not, a set distance to a subject is inputted to an arithmetic element 20. Then a signal is outputted from the arithmetic element 20 to a second driving element 21 and thereby an angle-deflecting prism mechanism 11 is operated to deflect the angle of an optical path properly. Then, inspection is made as to whether the result of this measurement of the distance is in accord with said distance or not. Since the optical path to the subject is shortened by the mechanism 11, on the occasion, the distance to the subject can be reduced. In addition, the quantity of light to be sensed by a light-sensing element 3 is lessened by controlling the quantity of light transmitted by a filter 7, on the occasion, and therefore the distance measuring apparatus 1 operates properly. Accordingly, a space for inspection of the distance measuring apparatus 1 can be reduced and secured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a range finder inspection device that tests whether a range finder that obtains distance information by photoelectric means is accurately measuring distance. .

[Conventional technology]

Some recent cameras are equipped with an O-1 focus device that moves the photographic lens to the in-focus position depending on the distance to the subject. The autofocus device has a range finder that obtains distance information to the object by photoelectric means, and such a range finder is shown in FIG. 5. In the figure, infrared light is emitted from a light projector 101 toward a subject 102, and is received by a light receiver 103 spaced apart from the light projector 101 by a predetermined baseline length L. Then, by calculating the output signal of the light receiving unit 103 based on the base line length L, distance information to the subject is obtained.

By the way, before a camera incorporating an autofocus device is shipped as a product, it must be inspected to see if the measuring device of the autofocus device is measuring accurately. Therefore, the distance to the subject is measured by placing the subject in front of the range finder, from near to far. In this way, a predetermined actual distance is required to measure the distance to a subject using a range finder.

[Invention or problem to be solved]

However, since a large inspection area is required to inspect the operation of the range finder of an autofocus device, it has recently become difficult to secure this inspection area. In addition, for example, as the factory site gradually becomes smaller, this inspection location encroaches on space for other purposes.

Therefore, efforts are being made to minimize the size of the inspection area and equipment by placing a reflecting mirror in the optical path to reflect the infrared rays. However, no matter how small the inspection location and equipment are by reflecting infrared rays, the light emitting part
The optical path length from 01 to the light receiving section 103 was still required. For this reason, the inspection area had to be large, and it was difficult to secure this inspection area. Also,
For example, there was a problem in that areas used for other purposes were still relatively eroded.

[Means for Solving the Problems] In order to solve such problems, the present invention includes the following:
A reflector is provided opposite to an All range finder having a light projecting part that projects light onto an object and a light receiving part that receives reflected light from the object, and is disposed in the light projection direction of the light projecting part of the range finder. a deflection prism mechanism that is interposed in the light projection path from the light projecting section to the reflecting section and deflects the step optical path in accordance with the distance of the object; The object is configured to include a light quantity control means which is interposed in the optical path and controls transmitted light according to the distance to the object.

[For production]

According to the present invention, when inspecting whether the range finder of an autofocus device is accurately measuring the distance to the subject, the optical path to the subject is shortened by the deflection prism mechanism. The distance can be shortened. Further, at this time, the amount of transmitted light is controlled by the light amount control means to reduce the amount of light received by the light receiving section, so that the illll range finder operates properly.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings. 1 to 4 are diagrams showing an embodiment of a range finder inspection device according to the present invention.

In FIG. 1, reference numeral 1 indicates a range finder of an autofocus device built into the camera, and this range finder 1 includes a light projector 2 that emits infrared light toward the subject, and a light projector 2 that emits infrared light toward the subject. Light part 2
It has a light receiving section 3 which is disposed a predetermined distance apart from the subject and receives reflected light from the subject. A standard reflector plate 4 (a support plate with gray paper pasted on it) is provided as a reflector shrine in the light emission direction of the light emitter unit 2, and in the light projection path from the light emitter unit 2 to the standard reflector plate 4. A deflection prism mechanism 11 is interposed therein.

As shown in FIGS. 2 and 3, the deflection prism mechanism 11 includes a pair of rotary prisms 12.13 (W-L T
(Trade name of CHNOLOGIES JAPANINC)
The outer periphery of the rotary prism 1.2.13 is supported and toothed portions are formed on the outer periphery, and the first and second rotating gears 14.15 and the first and second rotating south wheels 14.15 and the first and 27th idle south wheels 17.1 for rotating the first and second rotary gears 14.15 in opposite directions.
It consists of 8.

The pair of rotary prisms 12 and 13 are arranged opposite to each other in the direction of the optical axis, and surfaces opposite to each other are inclined surfaces. A first idle gear 17 meshes with the first rotating gear 14 , a second idle gear 18 meshes with the first idle gear 17 , and the second idle gear 18 meshes with the second rotating gear 15 .

On the other hand, the first idle gear 17 meshes with the drive gear 16.

When the drive gear 16 is rotationally driven by the first drive unit 19 such as a step motor, the first and second idle gears 17 .
18, the first and second rotating gears 14,15 are rotated in opposite directions. In this way, by rotating the rotary prism 12.13 in opposite directions by the first and second rotating floats 14.15, the infrared rays passing through the rotary prism 12.13 are refracted and blurred. This creates an angle between the two sides of the infrared rays, changing the direction of the infrared rays. That is, the direction of the infrared rays projected from the light projecting section 2 can be changed by operating the deflection prism mechanism 11.

By the way, when the subject is located far away, the angle at which the light is projected from the light projecting section 2 and exits from the deflection prism mechanism 11 toward the optical path from the subject to the light receiving section 3 is large, and the subject approaches. This angle of deviation becomes smaller as the angle increases. For this reason, the deflection prism mechanism 11 is operated by the first driving means 19 according to the position of the subject, and the direction of the infrared rays is changed. In other words, if the subject is located far away (
At position A in FIG.
Increasing the polarization angle (θ1) of the light receiving path up to
This time, conversely, the polarization angle (θ2) of the light emitting path and the light receiving path is made smaller.

A filter 7 is interposed between the reflection plate 4 and the light receiving section 3, and the filter 7 is made of disk-shaped glass as a whole, as shown in FIG. 4, and has a rotating shaft in its center. 7a is formed. Further, the filter 7 is an infrared ray filter that reduces the amount of transmitted light without changing the components of the incident light. The filter 7 has the same light attenuation rate in the radial direction, and is formed so that the light attenuation rate in the circumferential direction gradually differs.

Generally, when a subject is located at a long distance, the amount of reflected light received by the light receiving section 3 is attenuated in proportion to the square of the distance. However, since the optical path is shortened by the polarization prism mechanism 11 and the polarization angle is changed from a close position to a long distance position of the subject, the reflected light received by the light receiving unit 3 does not attenuate in direct proportion. . Here, when measuring a distant object with the range finder 1, distance measurement is performed based on the output signal of the light receiver 3 according to the polarization angle of the infrared rays as well as the attenuated light amount of the light receiver 3. I'm getting information. Therefore, when the optical path is shortened by the deflection prism mechanism 11, the amount of light received by the light receiving section 3 is not reduced according to the distance, so the range finder 1 does not operate properly and only obtains incorrect distance measurement information. You will not be able to do so.

Therefore, the amount of light attenuation of the light receiving section 3 according to the position of the subject is calculated by the calculation section 20 such as a microcomputer, the amount of light transmitted through the filter 7 is further calculated based on this amount of light attenuation, and the result of this calculation is used to control the step motor, etc. The second drive section 2 of
Output to 1. The second drive unit 21 rotates the rotation shaft 7a via a gear mechanism or the like according to the calculated amount of transmitted light, so that the light is reflected at a portion of the filter 7 with an appropriate light attenuation rate depending on the position of the reflection plate 4. position the infrared light beam. Therefore, infrared rays whose intensity is attenuated according to the distance to the subject are incident on the light receiving section 3, and accurate distance measurement information can be obtained.

Note that the filter 7, the first drive section 19, and the calculation section 2
0 constitutes a light amount control means as a whole. Further, the filter 7 may be manually rotated to an appropriate light attenuation rate depending on the position of the reflection plate 4.

On the other hand, although the filter 7 is interposed in the light receiving path between the reflecting plate 4 and the light receiving section 3, it may be interposed in the light projecting path between the light projecting section 2 and the reflecting plate 4, or the filter 7 may be interposed in the light receiving path between the light projecting section 2 and the reflecting plate 4. It may be provided over both of the light projection paths.

When inspecting whether the range finder 1 of the autofocus device is working accurately, input the set distance of the object to the calculation unit 20, and from this calculation unit 20 the second drive unit 2
1, a signal is output to actuate the deflection prism mechanism 11 to properly deflect the optical path. It is checked whether this distance measurement result matches the distance. At this time, since the optical path to the subject is shortened by the deflection prism mechanism 11, the distance to the subject can be compressed. Further, at this time, the amount of transmitted light is controlled by the filter 7 to reduce the amount of light received by the light receiving section 3, so that the range finder 1 operates properly. Therefore, the inspection area for the range finder 1 can be made smaller, and this inspection area can be secured. For example, even if a factory site gradually becomes smaller, it will not relatively encroach on space for other purposes.

In addition, instead of the filter 7, it may be selectively narrowed down with a shutter blade or the like, or PLZT, a transparent metal oxide made by adding La to a solid solution of P b Z r O a and P b T t O a, may be used. A sintered body may be used, or a method such as applying a voltage to the liquid crystal may be used.

Further, the technical idea of the present invention can be realized even if the reflection plate 4 is also moved in combination in accordance with the control of the deflection prism mechanism.

Furthermore, in the embodiment described above, an example was shown in which the application was applied to an inspection device for a range finder of an autofocus device of a camera.
The present invention is not limited to this, and may be applied to an inspection device for a range finder of a precision instrument.

〔Effect of the invention〕

As explained above, according to the present invention, the optical path is shortened by interposing the deflection prism mechanism in the forward direction of the light emitting section, and the amount of transmitted light in the optical path from the light emitting section to the light receiving section is appropriately controlled. Since the amount of light received by the light receiving section is reduced, the inspection area for the range finder can be made small, and this inspection area can be secured. Furthermore, even if, for example, a factory site becomes gradually smaller, it will not relatively encroach on space for other purposes.

[Brief explanation of drawings]

1 to 4 are diagrams showing one embodiment of a rangefinder inspection device according to the present invention, FIG. 1 is a schematic overall view of this inspection device, and FIG. 2 is an exploded view of the deflection prism mechanism. Perspective view, 3rd
The figure is a sectional view thereof, FIG. 4 is a perspective view of a filter used in this control means, and FIG. 5 is a schematic diagram of a conventional range finder. 1...Distance finder 2...Light emitter 3...
Light receiving section 4...Reflector plate 5...Collimator lens 7...Filter 19...First drive section 20...Calculation section 21...Second drive section

Claims (1)

[Claims] A reflecting member facing a range finder having a light projecting part that projects light onto an object and a light receiving part that receives reflected light from the object, and disposed in the light projection direction of the light projecting part of the range finder; , a deflection prism mechanism that is interposed in the light projection path from the light projecting section to the reflecting member and deflects the light projecting path in accordance with the distance of the object; and in the optical path from the light projecting section to the light receiving section. 1. A range finder inspection device comprising: a light amount control means that is interposed in the object and controls the amount of transmitted light in accordance with the distance to the object.