JPS6329219A - Optical temperature sensor - Google Patents

Abstract

PURPOSE:To obtain an optical temperature sensor of simple constitution which has small light passing loss and provides temperature detection by aligning optical axes of two optical fibers whose end surfaces face each other by a V groove and operating a movable member which holds the tip part of an optical fiber by using shape memory array. CONSTITUTION:The end surfaces of the two optical fibers 8a and 8b are set opposite each other through the V groove 9 and their optical axes are aligned with each other. The tip of the optical fiber 8a is run through the hole 14 of the movable member 10 and supported through coil springs 11 and 13. The coil-shaped memory alloy 12 which supports the movable member 10 pushes up the movable member 10 with its restoring force when the ambient temperature rises above constant temperature. At the same time, the tip of the optical fiber 8a shifts in position upward to cut off the transmission of light between both optical fibers 8a and 8b, so that this device functions as an optical temperature sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical temperature sensor using an optical fiber for detecting heating temperature.

BACKGROUND OF THE INVENTION Conventionally, this type of optical temperature sensor has had a configuration as shown in FIG. In FIG. 3, 11L.

1b is an optical fiber, 2a, 2bij rod lens, 2
Heh.

3 is a light shielding plate, 4 is a coil-shaped shape memory alloy, and 5 is a spring. In the figure, light emitted from an optical fiber 1a is converted into parallel light rays 6 by a rod lens 2a, passes through a hole 7 provided in a shielding plate 3, and is again focused by a rod lens 2b. incident on . When the outside temperature rises, the spring 4 made of a shape memory alloy, for example, contracts, so the shielding plate 3 blocks the parallel light rays 6, and the light hardly enters the optical fiber 1b. When the outside temperature falls, the shrinking force of the shape memory alloy spring 4 disappears, and the spring 6 contracts, causing the shielding plate 3 to return to its original position, so that the parallel light rays 6
passes through the hole 7 again and enters the optical fiber 1b.

The problem that the invention aims to solve In such a conventional configuration, the rod lens 2a.

Since two 2bi pieces are used, there are problems in that the transmission loss of light is large, the number of parts is large, and complicated optical axis adjustment is required during assembly. The present invention is intended to solve these problems, and aims to make it possible to assemble a 3-bay assembly with little light transmission loss, without the use of lenses, and with almost no adjustment. It is something.

Means for Solving the Problem In order to solve this problem, the present invention aligns the optical axes of two optical fibers with their end faces facing each other using a groove, and aligns the optical axes of at least one optical fiber. The optical fiber is held by a movable member, and the movable member is operated using a shape memory alloy to move the tip of the optical fiber to the outside of the groove.

Function: With this configuration, there are fewer components because no rod lens is used, and no optical axis adjustment is required because the groove is used. Furthermore, temperature can be detected with a simple configuration in which an optical fiber is moved using the shape change of the shape memory alloy due to temperature, and it functions as an optical temperature sensor.

Embodiment FIG. 1 is a block diagram of an optical temperature sensor according to an embodiment of the present invention. In FIG. 1, sa and sb are yen fibers,
9 is a V groove, 10 is a movable member, 11 is a coil spring, 12 is a coil-shaped shape memory alloy, 13 is an elastic body provided on the movable member 1o, such as a small coil spring, and 14 is a hole through which the optical fiber 8a is passed.

FIGS. 2 and 2b are explanatory diagrams of main parts of this embodiment.

The configuration and operation will be explained below with reference to FIG.

The optical fiber 8b is fixed in the V-groove 9. The optical fiber 8a has its tip opposed to the optical fiber 8b with an interval of about 3 μm, and is pressed into the groove 9. By abutting the optical fibers 8a and 8b using the V-groove 9 in this manner, the optical axes of the optical fibers can be mechanically aligned.

Reference numeral 12 in FIG. 1 is a coil-shaped shape memory alloy, which has the property of returning to its original shape after being deformed when the temperature exceeds a certain temperature.

At room temperature, the temperature of the shape memory alloy 12 is also at room temperature, and the coil spring 11 has a stronger compressive force than the coil of the shape memory alloy 12, so the movable member 10 is pushed down in the figure, and the shape memory alloy 12 is under pressure. The receiver is in a deformed state. In this state, the optical fiber 8a is moved by the coil spring 13 in the hole 14 provided in the movable member 10.
It is pressed into the V-groove 9 by a downward force in the figure. At this time, the optical axes of the optical fibers sa and sb coincide within the groove 9, and the light is transmitted from the optical fiber 8a to the optical fiber 8b.

Returning to FIG. 1 again, the explanation will be continued. When the ambient temperature rises to a certain level or higher, the coil-shaped shape memory alloy 12
generates a force to return to its original shape, pushes the movable member 1o upward, and compresses the coil spring 11. When the movable member 1o is pushed up, the tip of the movable member 1o protrudes upward as shown in FIG. The axes are shifted and light transmission between both optical fibers is interrupted.

As described above, this embodiment has a simple configuration without using a lens, and can detect a temperature rise within a constant range based on the presence or absence of an optical signal, and functions as an optical temperature sensor. Also, the moving optical fiber 8a is connected to the V grooves 9 and 6.

Since it is held by the coil spring 13 provided on the movable member 10, it is possible to construct an optical temperature sensor that is resistant to vibrations and the like.

In this embodiment, the V-groove 9 is used as the groove in which the optical fibers 8a and 8b are placed, but any groove shape, including a U-shape, may be used as long as the groove can fix the optical fibers. Further, although only the minus optical fiber 82L was moved outside the Iv groove 9, two optical fibers sa and sb may be moved.

Although the shape memory alloy 12 has a coil shape, any shape may be used.Furthermore, although the coil spring 13 has been described as an elastic body that holds the movable optical fiber 8a, it is also possible to use a coil spring 13. Hold it on a movable member, ■
It goes without saying that an elastic body of any configuration may be used as long as it has the function of being pressed into the groove 9.

Effects of the Invention As described above, according to the present invention, two optical fibers can be placed in the same groove and their optical axes can be aligned, so optical parts such as lenses are not required. This has the advantage that the optical axis adjustment is often required.

Furthermore, since the optical fiber to be moved is held within the movable member using an elastic body in the direction of pressing it into the groove, there is an effect that it is not affected by vibrations and the like.

Since the structure for blocking light is simple, it is highly reliable and has the effect of being miniaturized, making it possible to provide a light temperature sensor that is superior to conventional ones.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an optical temperature sensor according to an embodiment of the present invention, FIGS.
The figure is a perspective view of a conventional optical temperature sensor. 8...Optical fiber, 9...V groove, 10...Movable member, 11...Coil spring, 12...Mountain...
Coil-shaped shape memory alloy, 13... Coil spring, 14... Hole. Name of agent: Patent attorney Toshio Nakao and 1 other person8-
尤ふしば q-vgroove/Goichi-] 42 Travita-chobe J) Ramin' Bunki・Higokin/3-m- Yatoju Kana (]4 Rubane) 74-large 1st figure S-尤) 4 bar Q-v groove 10-1 movable m kiss) 竽/- specially made-D-y-do-F-don-a-8 part 1 Ku 4-'': J4 Ru trace is Ryutaiki, Seih gloss 5-No~ne 6-parallel 7--δmu\3 figure

Claims (1)

[Claims] two optical fibers provided in the same groove with their end faces facing each other; a movable member that allows the tip of at least one of the optical fibers to move freely outside the groove; a shape memory alloy that controls the movement of movable members;
and an elastic body held by the movable member in a direction to press the movable optical fiber into the groove.