JPH05113525A - Optical coupling unit and fiber photoelectric sensor using the same - Google Patents

Abstract

PURPOSE:To improve the coupling efficiency of an LED and an optical fiber by providing a reflection unit having a light outgoing hole having a very small area and a lens for condensing the outgoing light from the light outgoing hole at the end face of a very small region. CONSTITUTION:The outgoing light 11 emitted in a Lambert's distribution from a LED 10 is reflected by the reflection region 12 of the reflection unit 13 deposited with gold or aluminum, etc., by evaporation on a reflection surface is converged to the very small (small diameter) region 14 of the reflection unit 13 and is emitted from the light outgoing hole 15 of the very small area in a section. The light emitted from the light outgoing hole 15 to be an equiv. light source is collimated by a collimating lens 16 mounted on an outside box 30 to the collimated beams of light having no spread. These collimated beams of light can be made incident efficiently on the optical fiber 17. Consquently, the quantity of the outgoing light from the fiber emitting end is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical coupling unit for highly efficiently coupling a light source and an optical fiber.

[0002]

2. Description of the Related Art As a conventional method of coupling an LED and an optical fiber, as shown in FIG.
Direct coupling method for directly coupling to 2 or lens coupling method using a convex lens between the LED and the optical fiber (not shown)
There is.

[Problems to be Solved by the Invention]

However, as shown in "Optical Communication Device Engineering" (Engineering Book, pages 141 to 155), the direct coupling method is such that when the LED 2 is brought close to the end face of the optical fiber 1, the optical fiber 1 is connected to the optical fiber 1. Since the incident light increases, the coupling efficiency increases. However, if the distance is further approached, components exceeding the acceptance angle of the fiber will also enter the core and these will escape to the cladding layer, so that the coupling efficiency will not increase. The lens coupling method also has a problem in that the coupling efficiency is limited because the amount of light that escapes from the core to the cladding layer increases or the amount of light that enters the core decreases depending on the position of the lens.

The present invention solves the above problems of the prior art and improves the coupling efficiency between the light source and the optical fiber, and in order to improve the coupling efficiency between the light source and the optical fiber, a reflection unit for converging the divergent light from the light source to one point, and It is an object of the present invention to provide an optical coupling unit including a lens that collects light emitted from the reflection unit and efficiently enters the optical fiber.

[0005]

In order to achieve the above object, in the optical coupling unit of the present invention, gold or an inner surface is used.
It has a reflection unit in which aluminum or the like is vapor deposited, and an LED as a light source is attached to an LED attachment hole provided at one end of the reflection unit. In the vicinity of the LED light emitting area of the reflection unit, a reflection area that reflects the divergent light of the LED in one direction is formed, and at the other end of the reflection unit, a minute area whose cross section is a minute area compared to the reflection area is formed. The end face of the minute region has a light emitting hole having a minute area. The tip of the minute area of the reflection unit is attached to one end of the outer box, a collimator lens is arranged inside the outer box, and an optical fiber is attached to the other end of the outer box.

The reflection unit may be a combination of the unit upper part and the unit lower part, which are obtained by vapor-depositing gold or aluminum on the reflecting surfaces of the unit upper part and the unit lower part which are integrally molded by resin molding.

Furthermore, it is more effective to provide a collimating lens mounting groove, an LED mounting hole, and an optical fiber mounting hole in the upper part and the lower part of the unit, respectively.

The optical coupling unit having the above structure can be used in a fiber photoelectric sensor.

[0009]

In the optical coupling unit of the LED and the optical fiber configured as described above, the divergent light from the LED is reflected in one direction by the reflection area of the reflection unit, and the reflected light is further reflected in the minute area at the end of the reflection unit. Converge. Therefore, an equivalent point light source is obtained in the light emitting hole at the tip of the minute area, and the light from the equivalent point light source is collimated by the collimator lens and efficiently enters the optical fiber.

Further, as described above, it is integrally molded by resin molding and has a collimating lens mounting groove, an LED mounting hole,
By combining the upper part of the unit and the lower part of the unit having the fiber mounting holes, the coupling unit can be easily manufactured and assembled.

When this optical coupling unit is used in a fiber photoelectric sensor, light can be efficiently incident on the optical fiber.

[0012]

EXAMPLES Examples will be described with reference to the drawings.
In FIG. 1, the emitted light 11 emitted from the LED 10 in a Lambertian distribution is reflected by the reflection area 12 of the reflection unit 13 in which gold, aluminum or the like is vapor-deposited on the reflection surface, and in the minute (small diameter) area 14 of the reflection unit 13. The light is converged and emitted from the light emitting hole 15 whose cross section has a minute area. The light emitted from the light emitting hole 15 that serves as an equivalent point light source is collimated by the collimating lens 16 attached to the outer box 30, and becomes collimated light that does not spread and can efficiently enter the optical fiber 17. .

In the embodiment shown in FIGS. 2 and 3, in the high efficiency coupling unit 22 including the unit upper part 20 and the unit lower part 21 and the collimating lens 26 which are manufactured by resin molding, the reflection of the embodiment shown in FIG. There is a reflection area 23 formed by vapor-depositing gold or aluminum on the inner surface corresponding to the unit, and the LED 24 is attached to the LED attachment hole 28 at the end of the reflection area 23. The collimator lens 26 is fitted into the collimator lens mounting groove 25 at the center of the unit upper part 20 and the unit lower part 21, and the optical fiber 28 is mounted in the optical fiber mounting hole 27. Also in this embodiment, as in the embodiment of FIG.
The light emitted from the ED 24 can be efficiently incident on the optical fiber 28.

The present invention can also be applied to the case where a light emitting element other than the LED is used as the light source.

The optical coupling unit having the above structure can be used in a fiber photoelectric sensor.

[0016]

As described above, according to the present invention, the light from the light source is made incident on the optical fiber through the reflection unit having the light emitting hole having a minute area. When used for, the emitted light diverged from the light source of the fiber photoelectric sensor can be efficiently incident on the optical fiber, which increases the amount of emitted light from the fiber emission end. Therefore, when the object detection distance of the fiber photoelectric sensor is extended, and when the object detection distance is the same as that of the conventional technology, there is a gain margin in the amplifier unit that amplifies the detected light amount, and noise resistance and temperature characteristics are improved. The effect is achieved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the configuration of an embodiment of an optical coupling unit of the present invention.

FIG. 2 is a vertical sectional view showing the configuration of another embodiment of the optical coupling unit of the present invention.

FIG. 3 is a perspective view showing a configuration of a lower portion of the unit shown in FIG.

FIG. 4 is a vertical cross-sectional view showing a method of coupling an LED and an optical fiber according to a conventional technique.

[Explanation of symbols]

 1,17,28 Optical fiber 2,10,24 LED 11 Emitted light 12,23 Reflection area 13 Reflection unit 14 Micro area 15 Light emission hole 16,26 Collimating lens 20 Upper unit 21 Lower unit 22 High efficiency coupling unit 25 Collimating lens Mounting groove 27 Optical fiber mounting hole 29 LED mounting hole 30 Outer box

Claims (2)

[Claims] 1. A reflection unit having an LED mounting hole at one end and a minute region at the other end at a coupling portion of a light source and an optical fiber, and a light emitting hole having a minute area at an end face of the minute region. And an optical coupling unit having a lens for condensing light emitted from the light emitting hole. 2. A reflection unit having an LED mounting hole at one end, a minute region at the other end, and a light emitting hole having a minute area on an end face of the minute region, and light emitted from the light emitting hole. A fiber photoelectric sensor comprising an optical coupling unit having a lens for condensing light.