JPH1114432A - Optical sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical sensor by which a liquid and a flowing body can be detected at high speed without using an optical fiber by a method wherein a detection pat situated in a position faced with a light source and a light- receiving part is moved, by a gas pressure or a liquid pressure, inside a cavity part which is formed in the long direction of a prism body. SOLUTION: Compressed air which is generated by a pressurization device 3 is sent into a cavity pat 1B which is formed as an optical transmission line in the long direction of a prism body 1, and the detection part 2 inside the cavity part 1B is moved at high speed. In the detection part 2, a light reflection part used to change an optical path is fixed. Light from a light source 4 transmitted inside the cavity part 1B is reflected by a light reflection means, it changes a course by the prism face of the prism body 1, and it is incident on a light-receiving part 5 so as to detect the level of a flowing body. In addition, when the detection part 2 is moved by a liquid pressure, the inside of the cavity part 1B is filled with a transparent liquid whose influence on the transmittivity of light is small, and it is moved by applying a liquid pressure by the pressurization device 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical sensor which can be used for detecting the level of a flowable substance such as a liquid, and more particularly to an inspection of a concrete injection used for civil engineering construction. The present invention relates to an optical sensor suitable for use in the optical sensor.

[0002]

2. Description of the Related Art As a method of detecting whether concrete or mortar is filled in a predetermined space, the present applicant has previously described the use of reflection and refraction of light by a prism and the use of a cavity inside a prism. Invented an apparatus for continuously moving a detection unit connected to an optical fiber. (Japanese Patent Application No. 8
-323425)

However, in a sensor of this type, when the total length of the sensor is long, a long optical fiber is required, so that it takes a long time to wind up the optical fiber, and the detecting operation becomes efficient. There was a problem of not being a target.

[0004]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above-mentioned conventional problems, and provides a long optical sensor which does not malfunction due to the influence of electromagnetic induction and can continuously perform high-speed detection. The task is to do so.

[0005]

According to the present invention, as a result of diligent studies to achieve the above object, the present invention uses a hollow portion as an optical transmission line without using an optical fiber, and uses a pressing device as a detecting portion. The present invention has been completed in consideration of high-speed movement in the cavity by the gas pressure or liquid pressure caused by the pressure.

In order to solve the above-mentioned problem, the invention according to claim 1 is to provide a detecting unit located at a position facing a light source and a light receiving unit in a longitudinal direction of a prism body by gas pressure or liquid pressure by a pressurizing device. It is characterized in that it is moved within the provided cavity.

According to a second aspect of the present invention, in the first aspect of the present invention, a slit is provided at a position that is a part of the prism body and blocks an optical path from the light source to the light receiving section. Is what you do.

According to a third aspect of the present invention, there is provided an apparatus which does not use a prism for detecting a white liquid or a fluid,
The detecting unit is moved in the cavity provided in the longitudinal direction of the optical rod by gas pressure or liquid pressure by a pressurizing device, and is a part of the optical rod, which blocks an optical path from the light source to the light receiving unit. Characterized in that a slit is provided in the second member.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an example of the optical fiber sensor of the present invention, FIG. 2 is a longitudinal sectional view thereof, FIG. 3 is a sectional view taken along the line AA of FIG. 2, and FIG. . In FIGS. 1 to 3, 1 is a prism body, 1B is a cavity provided in the longitudinal direction of the prism body, 1C is a hydraulic or pneumatic air intake / exhaust hole,
Reference numeral 2 denotes a detecting unit, 3 denotes a pressing device, 4 denotes a light source, and 5 denotes a light receiving unit.

As shown in FIG. 4, a light reflecting means 2A for changing the optical path is provided on the detecting section 2 at an inclination angle of 45 degrees and a case 2B.
It is fixed to. Therefore, the cavity 1B of the prism body 1
The light from the light source 4 arriving inside the light reflecting means 2A
. Here, the course is changed by 90 degrees, and the light enters the prism surface 1A of the prism body 1 at an incident angle of 45 degrees. Note that a plane mirror or the like may be used as the light reflecting means 2A.

In FIG. 3, when the prism surface 1A is not in contact with a liquid or a fluid, since the refractive index of the prism portion is larger than the refractive index of the outside air, total reflection occurs at the prism surface 1A on the light emitting side. Then change course by 90 degrees.

Next, the light totally reflected on the light-emitting side prism surface 1A is similarly totally reflected on the light-receiving side prism surface 1A, and the course of the light is changed by 90 degrees. 2A is incident at an incident angle of 45 degrees.

Further, the course of the light is changed by 90 degrees again by the light reflecting means 2A, and the light enters the light receiving section 4 after passing through the cavity 1B. That is, an optical path L from the light emitting section 4 to the light receiving section 5 is formed. Here, the prism portion refers to an upper triangular prism portion of the prism body 1 which is directly involved in the reflection and refraction of light.

Next, when the prism surface 1A is in contact with a liquid or a fluid, the outside of the prism surface 1A changes from the air to the liquid (fluid) and the refractive index changes. The light incident on 1A is not totally reflected by the prism surface 1A, but is refracted to the outside of the prism body in the direction of m as shown in FIG. That is, the optical path L from the light source 4 to the light receiving section 5 as described above is not formed.

Therefore, the presence or absence of a liquid or a fluid near the detection unit 2 can be detected by checking a change in the amount of light received by the light reception unit 4. In addition, since the detection unit 2 can move at a high speed and continuously in the longitudinal direction of the prism body 1 by hydraulic or pneumatic pressure by the pressurizing device 3, continuous and high-speed detection can be performed over the entire length of the prism body 1. .

The detecting unit 2 can be moved at a high speed by generating compressed air by the pressurizing device 3 and sending the compressed air into the cavity 1B. When the detection unit 2 is moved by the liquid pressure, the cavity 1B is filled with a transparent liquid having little influence on the light transmittance, and the liquid pressure is applied by the pressurizing device 3. Further, it is preferable to add a suction (liquid absorption) function to the pressurizing device 3 because pressurization and suction can be performed freely and the detection unit 2 can be controlled more precisely.

Here, the shape of the prism body 1 can be arbitrarily selected, and the prism portion is an isosceles 3 having an apex angle of 90 °.
A prism is easy in design and is particularly preferable. The dimensions of the prism body 1 are also arbitrary, but one side of the prism surface 1A is particularly preferably about 10 mm to 30 mm.

Further, a cavity 1B is provided in the longitudinal direction of the prism body 1. The dimensions and shape of the hollow portion 1B are also arbitrary, but the cross section is 4 mm × 4 mm to 10 m.
A rectangle of mx 20 mm is particularly preferred. The prism body 1 can be formed by any processing method such as injection molding or extrusion molding.

The material of the prism body 1 is transparent, for example, glass, PMMA (polymethyl methacrylate),
Polycarbonate, vinyl chloride resin, fluorine resin and the like can be mentioned. In applications requiring heat resistance and chemical resistance, the material may be selected according to the application.

As the light source 4, a halogen lamp, a light emitting diode, a semiconductor laser or the like is used. The light receiving unit 5 uses a silicon photodiode or a silicon phototransistor.

Next, a slit 1 is formed in a part of the prism portion shown in FIG.
The case where D is provided will be described. When detecting a white liquid or a white fluid, since the white liquid or the fluid has a higher light reflectance than a normal liquid or a fluid, irregular reflection occurs on the prism surface 1A, and when the liquid exists. However, most of the light from the light source is incident on the light receiving unit, and the state is the same as when there is no liquid, and the detection is erroneous.

Therefore, as shown in FIG. 5, a slit 1D is provided in a part of the optical path L of the prism portion, and the presence or absence of transmitted light is detected by this slit.

In this way, even in the case of a white liquid or a fluid, the transmitted light is attenuated by the slit 1D, and the light emitted from the light source 4 does not reach the light receiving section 5. That is, the optical path L from the light source 4 to the light receiving section 5 is not formed, and the detection of the white liquid or the fluid becomes possible.

As described above, in FIG. 5, in addition to the detection of light using the reflection and refraction of light at the prism portion, the double detection of detecting the transmitted light of light at the slit portion ensures the white color. Liquid or fluid can be detected.

Here, the width of the slit 1D is 1 mm to 5 m.
m is particularly preferred. In FIG. 5, the slit 1D is provided at the vertex of the prism body. However, the slit 1D may be provided at any other location as long as it is a part of the optical path L of the prism portion.
Any number of slits can be selected.

Next, another embodiment of FIG. 6 which does not use a prism and is suitable for detecting a white liquid or a fluid will be described.

In this case, a slit 1D is provided in a part of the optical path L of the optical rod 6 having no prism, and only the transmitted light is detected here to detect a white liquid or a fluid. It is possible.

In this case, however, an optical path changing means such as a prism or a reflecting means for changing the light path inside the optical rod 6 is required. In this figure, 7 corresponds to an optical path changing unit.

[0029]

According to the optical sensor of the present invention, liquids and fluids can be detected at high speed. In addition, it is possible to detect a white liquid or fluid.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an optical sensor according to the present invention.

FIG. 2 is a longitudinal sectional view of the optical sensor of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a detailed view of a detection unit 2.

FIG. 5 is a longitudinal sectional view showing an embodiment in which a slit is provided in a prism portion.

FIG. 6 is a longitudinal sectional view showing another embodiment that does not use a prism.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 prism body 1A prism surface 1B cavity 1C intake / exhaust hole 1D slit 2 detector 2A light reflecting means 2B case 3 pressurizing device 4 light source 5 light receiving unit 6 light rod 7 light path changing means L light path

Claims (3)

[Claims] 1. An optical sensor, wherein a detecting unit located at a position facing a light source and a light receiving unit is moved in a cavity provided in a longitudinal direction of a prism body by gas pressure or liquid pressure by a pressurizing device. . 2. The optical sensor according to claim 1, wherein a slit is provided at a position that is a part of the prism body and blocks an optical path from the light source to the light receiving unit. 3. A detecting unit located at a position facing the light source and the light receiving unit, by gas pressure or liquid pressure by a pressurizing device.
An optical sensor which is moved in a hollow portion provided in a longitudinal direction of an optical rod and has a slit at a position which is a part of the optical rod and interrupts an optical path from a light source to a light receiving portion.