JPS62187214A - Micro-displacement detector - Google Patents

Abstract

PURPOSE:To detect displacement of a movable part at a high speed stably with high accuracy by arranging a light emitting part at the central position in opposition to a swingable key top having a reflection mirror and providing plural light receiving parts around it. CONSTITUTION:When there is not displacement on the movable part K and the key top 3 is vertical with respect to an axis of a housing 1, laser light emitted in an axial direction from a micro-lens 6 through an optical fiber 7 is reflected in a reverse direction by the reflection mirror 4. As a result, the reflected light is not detected with any light receiving part 8 in this state and it is detected that the displacement is zero. On the other hand, when the movable part K is slightly displaced and the key top 3 is inclined by a small angle against the force of a spring 2, the laser light emitted in the axial direction is reflected with the angle twice as large as the inclined angle of the key top 3 by the reflection mirror 4. This reflected light is made incident on the light receiving part 8a and detected as an electrical signal through an optical fiber 10. Accordingly, the inclined angle of the key top 3 is calculated by the recognition of the light receiving part 8a and the quantity of displacement and the direction of the movable part K can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting minute displacements with high precision, and particularly to a minute displacement detection device using light.

[Conventional technology]

Conventionally, switches operated on mechanical principles have been used as devices to detect small displacements such as moving distances and moving angles of moving parts, and switches are operated in response to the displacement of the moving parts to generate electrical signals. A detection method has been proposed. Usually, multiple switches are installed around the movable part, and by determining which switch is selectively activated depending on the direction and amount of movement of the movable part, can be detected.

[Problem that the invention seeks to solve]

Since the conventional detection device described above uses a mechanically operated switch, it is difficult to perform high-speed and stable detection due to switch contact failure, chattering, and the like. Further, since there is a limit to the miniaturization of switches, it is difficult to arrange a large number of switches close to a movable part, and it is difficult to detect minute displacements with high precision.

Furthermore, increasing the number of switches causes problems such as an increase in the size of the device.

[Means for solving problems]

The minute displacement detection device of the present invention is capable of detecting the displacement of a movable part at high speed, stably, and with high precision, and is capable of reducing the size of the device.

The minute displacement detection device of the present invention includes: a key top having a reflecting mirror on its inner surface and swinging as the movable part moves; and a light emitting part disposed opposite to the reflecting mirror at a central position of the key top. It consists of a plurality of light receiving sections arranged around this light emitting section.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of one embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line ■■■ in FIG.

This minute displacement detection device has a spiral spring 2 fitted around the inside of a cylindrical housing 1, and this spring 2 pivots a disk-shaped key top 3 to an open position of the housing 1. It is supported perpendicular to the direction. Therefore, the key top 3 can be swung in three dimensions with respect to the housing 1 when subjected to an external force. Further, this key top 3 has a flat reflecting mirror 4 integrally attached to the center of the inner surface, and a movable part K that detects minute displacement is in contact with a part of the outer periphery.

A light emitting section 5 that emits light in the axial direction of the housing 1 is fixed at the center of the bottom surface of the housing 1. In this embodiment, the light emitting unit 5 is composed of a microlens 6 and an optical fiber 7 connected to the microlens 6, and a laser beam inputted from an unillustrated tip of the optical fiber 7 is transmitted to the microlens 6 through the optical fiber 7. , so that it is ejected from here toward the key top 3 in the axial direction.

Further, a large number of light receiving sections 8 are arranged on the bottom surface of the housing 1 so as to surround the light emitting section 5. In this embodiment, these light receiving sections 8 are composed of a microlens 9 and an optical fiber 10 connected thereto, and the tips of the optical fibers 10 are each connected to an optical-to-electrical conversion element that constitutes a part of a detector (not shown). are doing. These light receiving sections 8 are arranged on a large number of concentric circles centered on the light emitting section 5, and aligned in the circumferential direction.

According to this configuration, when the movable part K is not displaced and the key top 3 is maintained perpendicular to the axis of the housing 1 as shown in FIG. The laser beam emitted in the axial direction is reflected by the reflecting mirror 4 in the opposite direction to the axial direction. Therefore, in this state, reflected light is not detected by any of the light receiving sections 8, and it is detected that the displacement is zero.

On the other hand, when the movable part K is slightly displaced and the key top 3 is tilted by a small angle against the force of the spring 2 as shown in FIG. 4
The light is reflected in a direction off-axis, that is, at an angle twice the inclination angle of the key top 3. Then, this reflected light enters the negative light receiving section 8a in the light receiving section 8, is transmitted from there through the optical fiber 10 to a detector (not shown), and is detected as an electrical signal. Therefore, by recognizing this light receiving portion 8a with a detector, the reflection angle of light and the inclination angle of the reflecting mirror 4, that is, the key top 3 can be calculated. Thereby, the amount and direction of displacement of the movable part can be detected.

As the amount of displacement of the movable part increases, the inclination angle of the key top 3 increases as shown in FIG. 4, and the light receiving part 8 that detects reflected light increases.
is also moved to the light receiving section 8b arranged on the outside in the radial direction. Therefore, by comparing the relative positions of these light receiving parts 8a and 8b, it is also possible to detect the relative displacement of the movable part.

Therefore, erroneous detection due to chattering or poor contact unlike mechanical switches does not occur, and the detection response is fast, so fast and accurate detection can be performed. In addition, since the light emitting section 5 and the light receiving section 8 are composed of optical fibers and microlenses, the light receiving section 8 can be arranged at a high density, improving detection accuracy and downsizing the device.

In addition, although the above explanation shows the case where the displacement in the radial direction is detected, the detection can also be performed in the circumferential direction in the same way, and thereby the displacement of the key top 3 and the movable part can be detected three-dimensionally. .

〔Effect of the invention〕

As explained above, the present invention has a structure in which a light emitting part is arranged at a central position facing a swingable key top having a reflecting mirror, and a plurality of light receiving parts are arranged around this light emitting part. Therefore, when detecting the displacement of the movable part, erroneous detection due to chattering or contact failure unlike mechanical switches does not occur, and the detection response is fast, so fast and accurate detection can be performed. Also,
The light emitting section and the light receiving section can be arranged at a high density, thereby improving detection accuracy and downsizing the device.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of an embodiment of the present invention, Fig. 2 is a sectional view taken along the n line in Fig. 1, and Figs. 3 and 4 are similar to Fig. 1 for explaining the operation. This is a diagram. DESCRIPTION OF SYMBOLS 1...Housing, 2...Spring, 3...Key top, 4...Reflector, 5...Light emitting part, 6...
Microlens, 7... Optical fiber, 8.8a, 8b...
- Light receiving section, 9...lens, 10...optical fiber. Agent Patent attorney Akio Suzuki; ζ゛Figure 1

Claims (2)

[Claims] (1) A key top that has a reflecting mirror on its inner surface and swings as the movable part moves, a light emitting part placed opposite the reflecting mirror at the center position of the key top, and a light emitting part arranged around the light emitting part. What is claimed is: 1. A minute displacement detection device comprising a plurality of disposed light receiving sections, the light receiving section being configured to detect light emitted from the light emitting section toward a reflecting mirror. (2) The key top is supported by a spring on a housing formed in the shape of a cylindrical container, and the reflecting mirror is fixed to the inner surface of the key top, and the light emitting part is arranged at the center of the bottom surface of the housing, and each light receiving part is arranged around the bottom surface of the housing. The minute displacement detection device according to claim 1, wherein the minute displacement detection device is arranged concentrically and circumferentially.