JPH02114112A - Fine angle measuring apparatus - Google Patents

Abstract

PURPOSE:To enable measurement at a high speed and at a high accuracy with a simple construction by using a light source with a phase adjusted properly while slits are arranged in a light receiving sector on the light transmitting side. CONSTITUTION:To improve reflection efficiency of a product 8 to be inspected, light from a light source 1 is transmitted with a polarizing plate 2. The light transmitted through the polarizing plate 2 is turned to one line of beam with a slit plate 3 to irradiate the product 8 to be inspected vertically. Being one line of vertical beam, the light is not affected in height to eliminate the need for a focusing function. The light reflected on the product 8 to be inspected is bent by 90 deg. with a half mirror 4 to be introduced to the slit plate 5. As the slit plate 5 is deviated by 90 deg. slitting from the slit plate 3, light from the slit plate 5 is given as a spot. Since the position of the spot moves depending on the right or left tilt of the product 8 to be inspected, an image thereof is formed on an area sensor 7 with an imaging lens 6 thereby enabling measurement of an inclination of the product 8 to be inspected.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a minute angle measuring device, and in particular, a minute angle f suitable for an automatic inspection device that can measure the inclination of a plane with high precision.
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[Prior art] In general, as described in "Encyclopedia deskJ" published by Kodansha and "Nikkei High Chic Dictionary" published by Nikkei Sangyo Shimbun, regarding the il + 1 constant of a minute angle, the light emitted from the focal point passes through the lens. Taking advantage of the phenomenon of parallelism, a glass plate with small holes, slits, or scales is placed at the focal point of the lens.
This is done manually using a so-called autocollimator that irradiates light from behind. However, the current situation is that focusing is required for each workpiece, and measurement time is required.

[Problem to be solved by the invention] The above conventional technology does not take into account the following points, 1: Adjustment is required and measurement time is required.

2: Two-dimensional angular distribution cannot be easily measured.

There were problems such as:

An object of the present invention is to eliminate the above-mentioned problems by combining a simple optical system and an electronic circuit to achieve automation.

[Means for Solving the Problems] When the above object is measured using an optical system, it is necessary to consider measurement errors due to variations in the height of the inspected product. Generally, an autofocus mechanism is installed, but to make it as simple as possible, we used light sources with one phase aligned and provided slits on the light-transmitting side and the light-receiving side, so that focus could be ignored. In addition, we decided to use optical magnification to measure small angles. For two-dimensional angle measurement, an area sensor is used as a light receiving element.

With the above configuration, high accuracy and no adjustment for automation can be achieved.

[Function] The minute angle measuring device of the present invention passes light of the same phase through a slit and projects a ray of light onto an item to be inspected. Since this projected line has no effect on variations in the height direction of the product to be inspected, a focus function is not required.

Then, when the light reflected by the inspected item is passed through a slit rotated 90 degrees with respect to the slit at the time of incidence, and an image is formed on the area sensor, the light spot will be directed in a direction perpendicular to the projected line. The object is to measure the inclination of the sensor by moving it over the sensor. Furthermore, the product to be inspected may be tilted front to back and left and right, but this can be handled by switching the slits on the light-transmitting and light-receiving sides or by providing two optical paths.

[Example] An embodiment of the present invention will be described below with reference to FIG.

This minute angle measuring device has a light source 1. Polarizing plate 2. slit 3
, 5, Half Mira 4. It is composed of an imaging lens 6 and an area sensor 7. Namely.

A light source 1, a polarizing plate 2 for extracting light with regular vibrations from the light source 1, a slit plate 3 for extracting a single strip of light, a half mirror 4 for irradiating the above-mentioned strip of light onto the inspection object 8 and extracting the reflected light, and the above-mentioned. It is equipped with a slit plate 5 provided with a slit orthogonal to a line of reflected light taken out via the half mirror 4, and an imaging lens 6 that images the light passing through the slit plate 5 on an area sensor 7. .

Next, a measurement method using this device will be described.

First, to improve the reflection efficiency at the product 8 to be inspected.

The light from the light rX1 is passed through the polarizing plate 2. The light that has passed through the polarizing plate 2 becomes a single line by the first slit plate 3 and is irradiated onto the inspected product 8 in a vertical manner. Since it is a vertical line, it is not affected by the height direction. This focus function becomes unnecessary. The light reflected by the inspected item 8 is bent by 90 degrees by the half mirror 4 and guided to the second slit plate 5. This second slit plate 5 is different from the first slit plate 3 because the slits are shifted by 1]0°.
The light that comes out becomes a point. Since the position of this point moves depending on the left and right inclination of the product to be inspected 8, the amount of inclination of the product to be inspected 8 can be measured by focusing this on the area sensor 7 using the imaging lens 6. Further, by increasing the distance between the second slit plate 5 and the area sensor 7, the sensitivity can be increased accordingly.

As shown in FIG. 2, by rotating the first slit plate 3 and the second slit plate 5 by 90 degrees, the inclination of the product to be inspected 8 in the front-rear direction can be measured.

[Effects of the Invention] As described in detail above, the minute angle measuring device according to claim 1 of the present invention has a simple configuration, can measure at high speed and with high precision, and has excellent practical use in automatic inspection equipment, etc. effective.

[Brief explanation of drawings]

Fig. 1 is an overall configuration diagram of a minute angle measuring device for determining the horizontal inclination of an object to be inspected according to an embodiment of the present invention, and Fig. 2 shows the direction of the two slits in Fig. 1. Change the longitudinal inclination of the object to be inspected! 61... Light source, 2.
...Polarizing plate, 3...Slit, 4...Half mirror,
5... Slit, 6... Imaging lens, 7... Area sensor, 8... Item to be inspected. Patent applicant Hitachi Shonan Electronics Co., Ltd. Agent Patent attorney Masami Akimoto (1 other person) Procedures +l
i IE book (spontaneous) December 15, 1988 1

Claims (1)

[Claims] 1. A light source, a polarizing plate that extracts light with regular vibrations from the light source, a first slit plate that irradiates the inspected item with the striped light, and a half mirror that extracts the reflected light from the inspected item, which is perpendicular to the striped light. a second slit plate having a slit to extract dotted light; an imaging lens that forms an image of the light passing through the slit on a sensor; and an area sensor that measures the amount of inclination of the object to be inspected at the position where the light is focused. A minute angle measuring device equipped with: