JPH06229846A - Pressurization sensor - Google Patents

Abstract

PURPOSE:To enable a pressurization sensor to detect pressures from all directions without causing a performance drop or insufficient insulation due to water by utilizing the variation of the amount of transmitted light through an optical fiber caused by the deformation of the fiber. CONSTITUTION:An optical fiber 1 is formed by using silicone rubber for its core 4 and silicone rubber or elastomer having a refractive index lower than that of the silicon rubber used for the core 4. A light source 2 composed of an LED, LD, etc., is fitted to one end of the fiber 1 and a light receiving body 3 composed of a photodiode, phototransistor, etc., is fitted to the other end. When a pressure is applied to the fiber 1 from the outside, the fiber 1 is deformed and the amount of transmitted light through the fiber 1 varies. As a result, the amount of received light by the light receiving body 3 changes. By utilizing the change in the light receiving amount, a switch, etc., is actuated. Since the signal of this pressure sensor is propagated through light, the sensor can perform pressure detection outdoors, in water, etc., where the sensor is wet with water without receiving any influence from water. In addition, since the fiber 1 is deformed in any direction, the sensor can detect pressures from all directions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor that can be used as a pressure switch or the like.

[0002]

2. Description of the Related Art Conventionally, a switch having a mechanical movable contact structure such as a micro switch or a tape-like switch has been widely used in various mechanical devices, automobiles and the like.

A pressure conductive switch in which conductive rubber is interposed between a pair of electrodes has also been proposed (Japanese Patent Laid-Open No. 61-61).
143913).

[0004]

In such a conventional pressure switch, when it is used outdoors, in water, or when it is splashed with water, the electrodes and contacts are oxidized to deteriorate the performance and cause insulation failure. There was a problem.

Further, if waterproofing is applied to prevent the influence of water, the structure of the switch becomes complicated and the size becomes large.

Further, the conventional pressure switch operates only by the pressure in a fixed direction, and the switch cannot be operated by detecting the pressure from all directions.

An object of the present invention is to solve the problems of the conventional pressure switch, to eliminate the fear of performance deterioration and insulation failure due to water, and to detect pressure from all directions. To provide.

[0008]

As a result of intensive studies to achieve the above object, the present inventor has noticed that the amount of light transmission changes when an elastic optical fiber is deformed. Considering using it as a pressure sensor,
The present invention has been completed.

That is, in the present invention, the core is silicone rubber,
The pressure sensor is characterized in that a light source is provided at one end of an optical fiber whose clad is made of silicone rubber or elastomer having a refractive index lower than that of the silicone rubber, and a light receiver is provided at the other end.

[0010]

The present invention utilizes development in which the amount of light transmitted through the optical fiber changes when the elastic optical fiber is deformed.

Since the optical fiber used in the present invention has a core made of silicone rubber and a clad made of silicone rubber or elastomer having a refractive index lower than that of the silicone rubber, it is extremely elastic and easily deformed by external pressure. .

Due to this deformation, the amount of light passing through the optical fiber, that is, the output of the light beam is reduced. Therefore, when light is sent from the light source provided at one end of the optical fiber to the light receiving body provided at the other end, the amount of light received by the light receiving body changes due to the deformation of the optical fiber, and it is detected that pressure is applied to the optical fiber. The switch may be operated according to the change in the amount of light received by the light receiver.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view showing an example of the pressure sensor of the present invention, and FIG. 2 is a transverse sectional view showing an example of an optical fiber used in the present invention.

In FIG. 1, 1 is an optical fiber and 2 is an L.
Light sources such as ED and LD, and 3 are light receiving bodies such as photodiodes and phototransistors.

The optical fiber 1 is composed of a core 4 and a clad 5, as shown in FIG. The core 4 is made of silicone rubber, and the clad 5 is made of silicone rubber or elastomer having a lower refractive index than the silicone rubber of the core 4. Examples of the silicone rubber used for the core 4 include dimethylsiloxane polymer, phenyl group- or naphthyl group-containing siloxane polymer, and methylvinylsiloxane polymer.

In the clad 5, a silicone rubber having a lower refractive index than the silicone rubber used in the core 4, or
An elastomer such as a fluoroelastomer is used.

The fluoroelastomer used for the clad 5 may be, for example, a ternary fluororesin elastomer. In particular, a fluororesin portion (hard segment, for example, ethylene-tetrafluoroethylene copolymer) and a fluororesin are used. Rubber part (soft segment, for example, vinylidene fluoride-hexafluoropropylene-
A fluoroelastomer composed of (tetrafluoroethylene copolymer) is preferably used.

In order to manufacture the optical fiber 1 used in the present invention, first, a silicone rubber or an elastomer serving as a clad component is used, which has a diameter of 1 to 50 mm and a thickness of 0.2 to 2.5.
A tube having a size of about mm is molded, and then a liquid silicone rubber precursor is injected or sucked into the tube, and the silicone rubber precursor is polymerized and cured by any means such as heating, ultraviolet rays, and radiation to form a core component. Good. It is also possible to perform extrusion molding by co-extruding the core component and the clad component.

In the present invention, it is preferable that the core 4 and the clad 5 are not completely adhered to each other and the interface is peeled off because the change in the amount of light transmission becomes large when deformed.

When the pressure sensor of the present invention is used, if pressure is applied to the optical fiber 1 from the outside, the optical fiber 1 is deformed and the amount of light transmission changes, and the amount of light received by the light receiver 3 changes. The switch may be operated according to the change.

[0021]

According to the pressure sensor of the present invention, since the signal medium is light rather than an electric machine, pressure detection can be performed outdoors, in water, or in a place exposed to water without the influence of water. You can Moreover, since the optical fiber is deformed by the pressure applied from any direction, the pressure from any direction can be detected.

Further, since it is excellent in elasticity and flexibility, it can be easily used even in a complicated installation place.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an example of a pressure sensor of the present invention.

FIG. 2 is a cross-sectional view showing an example of an optical fiber used in the present invention.

[Explanation of symbols]

 1 Optical fiber 2 Light source 3 Photoreceptor 4 Core 5 Cladding

Claims (2)

[Claims] 1. A light source is provided at one end of an optical fiber whose core is made of silicone rubber and whose clad is made of silicone rubber or elastomer whose refractive index is lower than that of the silicone rubber.
A pressure sensor having a light receiving body at the other end. 2. The pressure sensor according to claim 1, wherein the clad is made of a fluoroelastomer.