JPH01152343A - Photosensor - Google Patents

Abstract

PURPOSE:To achieve a higher impact resistance and a higher directivity, by employing a flexible optical fiber bundle as photoconductor to make an outgoing end and a light receiving end thereof function as cylindrical lens. CONSTITUTION:Fiber bundles 7 and 8 are made flexible or semiflexible to improve an impact resistance as a whole by absorbing or easing an impact applied to the photoconducting part. In large-dia. columnar fibers at an outgoing section and a light receiving section, the side thereof as opposed to a reflecting surface set at 45 deg. with respect to an optical axis are used as outgoing end and light receiving end to function as cylindrical lens. Thus, outgoing light is made directive while an incident light coverages thereby achieving a higher sensitivity as sensor.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to optical sensors.

[Prior Art] Japanese Patent Application No. 61-226218 proposes the use of a cylindrical fiber having a core-clad structure in the light guide section of an optical sensor, but the light guide member has weather resistance, heat resistance,
Although it has excellent transmission efficiency, it has a relatively large diameter (several mm).
Because it is integrated with glass or plastic, if the optical sensor is used without protection and is subjected to a shock or dropped, accidents may occur, such as the cylindrical fiber breaking midway.

[Problems to be solved by the invention] Due to the above-mentioned problems, if impact resistance is required, the light guide section should be placed in a highly rigid casing via a soft material, or A method is adopted in which the light guide itself is divided into several parts, but the former increases the overall size, and the latter causes a decrease in efficiency due to reflection loss at the end face of each divided member. There was a problem that the usage was limited.

An object of the present invention is to solve the above-mentioned problems and provide a highly reliable optical sensor with low durability and light propagation loss.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and includes a light guide section that guides light from a light emitting element, and a light guide section that is connected to the light guide section and is connected to the light guide section. a light-emitting section that emits and guides dazzling light to an object or a test location; a light-receiving section that receives the light guided to the test object or test location; and a light-receiving section that is continuous with the light-receiving section. In the optical sensor, the light emitting part and the light receiving part each include a core having a reflective surface set at 45 degrees with respect to the optical axis at one end. An optical sensor comprising a cylindrical fiber having a cladding structure, and wherein a light guiding section between the light emitting element and the emission section and a light guiding section between the light receiving section and the light receiving element are composed of an optical fiber bundle. It provides:

Embodiments of the present invention will be explained below. FIG. 1 is a sectional view of the basic configuration of the optical sensor of the present invention, in which light from a light emitting element 1 is guided by a fiber bundle 7 to a cylindrical fiber 11 at an output section, and is directed at an angle of 45 degrees to the optical axis. The traveling direction is changed by the cut reflective surface, and the light is emitted from the side surface of the cylindrical fiber eye opposite to the reflective surface, and is directed toward the light-receiving side light guide section 12. The light incident on the side surface of the light-receiving side cylindrical fiber 12 is cut at 45'' with respect to the optical axis of the fiber 12, changes its course at the reflective surface facing the side surface, and is received after passing through the fiber bundle 8. The fiber bundles 7 and 8 have a core made of multi-component optical glass or heat-resistant optical plastic with a high refractive index, and a cladding made of multi-component glass or plastic with a lower refractive index. A large number of fibers are bundled together, their ends are integrated with heat-resistant adhesive, and both end faces are polished. At this time, caps are attached to both ends as shown in 3.4.9.10. May be used.

Therefore, both ends of the fiber bundle 7 are integrated, but the middle part excluding the ends is flexible or semi-flexible. In addition, cylindrical fiber 1
1.12 is made by using the same core and cladding materials as the fiber bundle, making the diameter equal to the diameter of the fiber bundle, and polishing one end at right angles to the optical axis and the other end at an angle of 45". These fiber bundles and cylindrical fibers are usually arranged and fixed in a sleeve having openings such as 5.6 as the light emitting and light receiving ends to serve as the light guiding part, the light emitting part and the light receiving part of the optical sensor. The length of the cylindrical fiber is determined based on the rigidity of the sleeve and the bending radius due to the actual impact, so that it will not break during an impact.

[Function] In the optical sensor according to the present invention, by making the fiber bundle flexible or semi-flexible, the impact applied to the light guide part is absorbed or alleviated, and the impact resistance as a whole is improved. Furthermore, the large-diameter cylindrical fiber of the emitting part and the light receiving part functions as a cylindrical lens by using the side surface of the fiber facing the reflective surface set at 45 degrees with respect to the optical axis as the emitting end and the light receiving end. , gives directivity to the emitted light and converges the incoming light, improving the sensitivity of the sensor.

[Example 1] Fibers with a diameter of about 50 μm using Flin optical glass as the core and crown optical glass as the cladding are bundled to form a handle with a diameter of about 4 mm and a length of about 120 mm, and both ends are integrated with heat-resistant epoxy resin. After polishing, both end faces were polished to a mirror finish. The middle part of the handle was filled with silicone rubber to make it semi-flexible. Next, a large diameter fiber with a diameter of about 4 mm was made using the same glass, and one end was polished to a 45° angle and the other end was mirror polished to a length of about 20 mm. As shown in Figure 1, these are placed and fixed in a metal sleeve with a thickness of 1 mm using heat-resistant epoxy adhesive, and an LED I as a light emitting element and a photodiode 2 as a light receiving element are placed at the upper end of the handle. It was used as a light sensor. This sensor was set at a sensor spacing of 80 mm and was used continuously (for more than two weeks) at an environmental temperature of about 100° C. near the light guide, but no particular problems occurred. In addition, although the sensor was subjected to shock several times due to contact with other mechanical parts or collision with a test object during sensor setup, no damage or decrease in sensitivity was observed.

[Example 2] Acrylic plastic optical fibers with a diameter of about 200 μm were bundled to form a bundle with a length of about 250 mm and a diameter of about 4 mm, and the same cylindrical fiber as in Example 1 was used for the output and light receiving sections. I created an optical sensor as shown in the figure. A silicone rubber tube was used for the sleeve. This sensor has been tested for continuous use and drop testing at an environmental temperature of approximately 70°C.
No damage was caused to a height of 70 cm).

[Effects of the Invention] As described above, the optical sensor of the present invention has improved impact resistance by using a flexible optical fiber bundle as a light guide. This also makes it easier to set up sensors at any location at the same time. In addition, the output end and light reception end function as cylindrical lenses, making it a highly directional and efficient sensor.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the optical sensor of the present invention, FIG. 2 is a cross-sectional view along line AA' in FIG. 1, FIG. 3 is a cross-sectional view along line BB' in FIG. FIG. 5 is a block diagram of another embodiment of the sensor, and FIG. 5 is a block diagram of a conventional example. L...Light emitting element 2...Light receiving element 3.4.9.10...Fiber bundle base 5.6...Sensor sleeve 7.8...Optical fiber bundle (guide Optical part) 11.12...Cylindrical fiber (light guiding part with reflective surface) 13...Object to be tested 14...Optical fiber 1 Figure 5 Figure 2 Figure 1 Figure 4

Claims (2)

[Claims] (1) A light guide section that guides light from a light emitting element, an emitting section that is continuous with the light guide section and that emits and guides the light to the test object or test location, and the test object or test site. A light sensor comprising a light receiving section that receives the light guided to the detection point, and a light guide section that is continuous with the light receiving section and guides the light received by the light receiving section to the light receiving element. The part and the light receiving part are each made of a cylindrical fiber with a core-clad configuration, one end of which has a reflective surface set at 45 degrees with respect to the optical axis, and a light guide part between the light emitting element and the light emitting part. Furthermore, an optical sensor characterized in that a light guiding section between the light receiving section and the light receiving element is composed of an optical fiber bundle. (2) The light emitting end of the emitting section is a side surface of the cylindrical fiber facing the reflective surface, and the light receiving end of the light receiving section is a side surface of the cylindrical fiber facing the reflective surface. The optical sensor according to claim 1, characterized in: