JPS6363918A - Optical type position detecting system - Google Patents

Abstract

PURPOSE:To achieve a smaller size of the equipment, by a method wherein light from a light source is made incident on a transparent part of a mobile slit plate, reflected on a mirror surface therebehind and transmitted through a slit pattern of a mobile slit plate and a fixed slit plate again to be received with a photodetector. CONSTITUTION:Light emitted from a fixed light source 1 is made incident slantly on a transparent part 9 of a mobile plate 7 and reflected with a mirror surface part 10. A slit pattern part 8 of the slit plate 7 is irradiated from the back thereof and the light is received with a photodetector 4 passing through a slit pattern of a fixed slit plate 3. The movement position of the slit plate 7 is detected from an output of the detector 4. Thus, the light source 1 and the detector 4 are arranged on the same side for each of the slit plates and a moving body and the mobile slit plate 7 can be coupled firmly thereby achieving a smaller size.

Description

[Detailed Description of the Invention] [Summary] The present invention is an optical position detection method using a slit plate, in which a light source and a photodetector are installed on the same side of the slit plate in order to downsize the entire system. .

[Industrial application field]

The present invention relates to a position detection device, and more particularly to an optical position detection method that enables miniaturization of the device.

[Conventional technology]

FIG. 4 shows a perspective view of a conventional optical position detection device. In the figure, 1 is a fixed light source, 2 is a moving slit plate, 3 is a fixed slit plate, and 4 is a photodetector. The light emitted from the fixed light source 1 in the direction of the photodetector 4 is converted into light that is intermittently blocked by the movable slit plate 2 moving in the direction of arrow F, and then cut to the required width by the fixed slit 3. The limited light received by the photodetector 4 flickers as the movable slit plate 2 moves. The output of the photodetector 4 is processed by a signal processing section (not shown), thereby detecting the moving position of the movable slit plate 2.

It is known that the slit pattern of each of the slit plates 2.3 uses a combination of slits with different phases (not shown) in order to identify the direction of movement, but this will not be explained here because it is not directly related to the present invention. omitted.

[Problem that the invention seeks to solve]

According to the conventional example, the movable slit plate 2 and the fixed slit plate 3 are interposed between the fixed light B1 and the photodetector 4, which has the disadvantage that the entire system becomes large.

FIG. 5 shows an assembled sectional view of the main parts of FIG. 4. In the figure,
5 is a mold part that holds the fixed light source 1 and the photodetector 4 so as to face each other, and 6 is a movable body that holds and moves the movable slit plate 2.0 As shown in the figure, the movable slit plate 2
The supporting means of the movable body 6 supporting the movable body 6 is cantilevered, resulting in a structure lacking rigidity, which has the disadvantage of being susceptible to vibration.

The present invention has been created in view of the above-mentioned drawbacks of the conventional art, and it is possible to miniaturize the entire system, and also to reduce the size of the movable slit plate 2 and the movable body 6.
The purpose of the present invention is to provide an optical position detection method that can strengthen the coupling between the two.

[Means for solving problems]

As shown in FIG. 1, the optical position detection method of the present invention includes a movable slit plate 7 formed on a part of one surface of a transparent member having parallel surfaces, with slit pattern portions 8 equidistantly spaced along the moving direction.
, a mirror surface part 10 is formed on the other surface, and a fixed light source l, a fixed slit plate 3 and a photodetector 4 are arranged facing each other on one surface of the movable slit plate 7. ing.

[Effect]

After the light emitted from the fixed light source 1 passes through the transparent section 9 on one side of the movable slit plate 7, it is reflected at the mirror surface section 10 on the other side, and the reflected light returns to the slit pattern section 8 on one side. After passing through, the light passes through the slit pattern of the fixed slit plate 3 and enters the photodetector 4.

In this way, the photodetector 4 and the fixed light beam al can be arranged together with the fixed slit plate 3 on the same side with respect to the movable slit vi7, making the entire system compact and supporting the movable slit plate 7 with respect to the movable body 6. The means can also be made more rigid as shown in the side view of FIG.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

Note that, in order to make the explanation of the configuration and operation easier to understand, the same parts are given the same reference numerals throughout all the figures, and repeated explanation thereof will be omitted.

FIG. 1 shows a perspective view of an embodiment of the invention. In the figure,
The movable slit plate 7 has slit pattern portions 8 and transparent portions 9 arranged at equal intervals along the moving direction shown by the arrow F on one side of a transparent member having parallel surfaces, and a mirror surface portion 10 on the other side. is forming.

FIG. 2 is a side view of FIG. 1, showing the optical path from the fixed light source 1 to the photodetector 4 and the coupling surface between the movable body 6 and the movable slit plate 7. As shown in the figure, the fixed light source 1 The emitted light is obliquely incident on the transparent portion 9 of the movable slit plate 7 and transmitted therethrough, and the transmitted light is reflected by the mirror surface portion 10. The reflected light illuminates the slit pattern portion 8 of the movable slit plate 7 from the back side, and the transmitted light further passes through the slit pattern of the fixed slit plate 3 and is received by the photodetector 4.

Therefore, the fixed light source 1 and the photodetector 4 can be placed on the same side with respect to each slit plate.

Furthermore, since the entire surface of the movable slit plate 7 can be used as the coupling surface between the movable body 6 and the movable slit plate 7, a strong attachment is possible.

FIG. 3 shows a side view of another embodiment of the invention.

In the figure, 3a and 3b are fixed slit plates of the same type, and 4a and 4b are photodetectors of the same type, respectively.

8a and 8b are the same type of equally spaced slit pattern parts, 11 is a transparent part, and the slit pattern parts 8a and 8 are transparent.
b along the movement direction, and constitutes a moving slit plate 12 together with the mirror surface part 10. The slit patterns of the slit pattern portions 8a and 8b are arranged in different phase relationships and are used for determining the moving direction described above.

The light emitted from the fixed light source 1 is transmitted through the transparent section 11 of the movable slit plate 12.
The transmitted light is reflected by the mirror surface part 10, and the reflected light is split into two directions and illuminates the slit pattern parts 8a and 8b formed on one surface from the back side. The light passes through the slit patterns of fixed slit plates 3a and 3b and is received by photodetectors 4a and 4b, respectively.

Each output of the photodetectors 4a and 4b is used to detect the moving position of the moving body 6, including the moving direction, by a signal processing section (not shown).

Note that the arrow F indicating the moving direction of the moving body in the above explanation
is applicable not only to linear motion but also to rotational motion.

〔Effect of the invention〕

As explained in detail above, according to the optical position detection method of the present invention, the fixed light source and the photodetector can be arranged together on one side of the slit plate, so the system can be made smaller. In addition, since the connection between the movable slit plate and the movable body can be strengthened, it is less susceptible to vibrations.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an embodiment of the present invention, Fig. 2 is a side view of Fig. 1, Fig. 3 is a side view of another embodiment of the invention, and Fig. 4 is a conventional optical position detection device. The perspective view, FIG. 5, shows an assembled sectional view of the main part of FIG. 4. In the figure, 1 is a fixed light source, 2, 7, and 12 are movable slit plates, 3, 38, and 3b are fixed slit plates, 8, 8a, and 8.
b indicates a slit pattern section, 9 and 11 transparent sections, and 10 a mirror surface section. Based on the figure 3 of Figure 2, 40 of 40, 1 T, 1 T, 1 T, 1 T; Clause 2 F?

Claims (1)

[Claims] A moving slit plate having an equally spaced slit pattern is irradiated with light from a fixed light source, and the transmitted light from the slit pattern is transmitted through a fixed slit plate having the same slit pattern as the moving slit plate. In the device in which the moving position of the movable slit plate is detected by a photodetector and a change in the amount of light received by the photodetector due to a change in the position between both slit plates, the movable slit plate (7) is arranged on a parallel surface. slit pattern parts (8) are formed at equal intervals along the movement direction on a part of one surface thereof, and mirror surface parts (10) are formed on the other surface, Fixed light source (1), fixed slit plate (3) and photodetector (
4) are respectively arranged to face one side of the movable slit plate (7), and the light from the fixed light source (1) is incident on the transparent part (9) on one side of the movable slit plate (7). and the mirror surface of the other surface (
10), then passes through the slit pattern section (8) on one side again, and then passes through the slit pattern of the fixed slit plate (3) and enters the photodetector (4). An optical position detection method featuring