JPH01242931A - Temperature sensor - Google Patents

Abstract

PURPOSE:To enable temp. measurement with high-accuracy without receiving the influence of the working accuracy of a reflecting film and without including an adhesive layer in an optical path by disposing the anti-reflecting film of a compd. semiconductor to face the anti-reflecting film of an optical fiber apart a prescribed spacing. CONSTITUTION:The incident light from the optical fiber 1 transmits the anti-reflecting film 11, the spacing 16, the anti-reflecting film 12, and the compd. semiconductor 13, reflects on the reflecting film 13, transmits again the compd. semiconductor 2, the anti-reflecting film 12, the spacing 16 and the anti-reflecting film 11 and enters a light receiving part (not shown in the figure) via the optical fiber 1. The temp. of the heat on the outside part of a protective tube 5 transmitted to the compd. semiconductor 2 is measured in accordance with the intensity of the light which transmits the compd. semiconductor 2 back and forth and is subjected to modulation in accordance with the temp. in the light receiving part. The anti-reflecting film 11 of the optical fiber 1 and the anti-reflecting film 12 of the compd. semiconductor 2 are slightly parted from the reflecting film 13 of the compd. semiconductor 2 and the sealed inside part of the protective tube 5 apart the prescribed spacing 16 and, therefore, there are no damages and since the reflecting film 13 is deposited on the compd. semiconductor 2, the temp. is measured with the high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a reflection type temperature sensor that is attached to one end face of an original fiber and utilizes the correlation between the absorption edge wavelength of light that passes through compound semiconductor gold and its temperature. It is related to sensors.

[Conventional technology]

FIG. 8 shows, for example, the key Ig? 111 is a fiber as a light transmission medium; 12) is a compound semiconductor whose absorption edge wavelength changes depending on the temperature; +31 is a reflection plate made of, for example, carp or chromium; (4a) is one end face of the original fiber +11 and one direction of the compound semiconductor +21? Adhesive layer to adhere (4
b) an adhesive layer of an adhesive that adheres the other surface of the compound semiconductor 12) and the reflective surface of the reflective plate 131; 61, the tip of the original fiber il+ and the compound semiconductor bonded to this end surface; 21 and the reflecting plate 13 glued to this other surface! It is a thermally conductive protective tube with a cap on it.

The conventional temperature sensor has a predetermined wavelength distribution V, which is propagated from a transmitting section (not shown) configured as described above through an optical fiber 111, an adhesive layer (4a), and a compound semiconductor layer 21.
．． It passes through the adhesive layer (4b) sequentially and is reflected by the reflective plate 131, and then the adhesive layer r4b), the compound semiconductor (21° adhesive layer r4)
a) and enters the original receiver (not shown) via the optical fiber ll'i. The compound semiconductor (2) is, for example, a crystal of CdT e consisting of elements from the 0 group and the Ma group, or a GaA3 crystal consisting of the elements of the LII group and the Ma group, and the absorption edge wavelength of the transmitted light changes depending on its temperature. When light with a predetermined wavelength distribution completely passes through the compound semiconductor (2), the protective tube 16)
The light is modulated by heat conducted from the outside of the compound semiconductor (2), absorbing light of a predetermined wavelength or less and transmitting light of a predetermined wavelength or more, depending on the temperature of the compound semiconductor (2). The temperature of the heat outside the protection tube 5) conducted to the compound semiconductor 21 is measured based on the intensity of the light that is modulated in accordance with the temperature.

[Problem to be solved by the invention]

In the conventional temperature sensor as described above, the thickness of the adhesive layer r4a) (4b) that transmits r/'i back and forth varies, the volume and refractive index change depending on the temperature, and the processing accuracy of the reflecting plate 13) also changes. There was a problem that needed to be solved: the variations affected the intensity of the light incident on the optical receiver, making it impossible to measure temperature with high accuracy.

In order to solve the above-mentioned problems, this invention has been developed as a temperature sensor that can measure temperature with high precision without including adhesive # in the optical path and without being affected by the processing accuracy of the reflector. The purpose is to

[1v1 assignment! Means for Determining] Is there an anti-reflective coating on one side of the temperature-controlled lantern according to the present invention and a reflective hood on the other? A compound semiconductor whose absorption edge wavelength of transmitted light changes depending on the applied temperature, an antireflection coating of this compound semiconductor, and an optical fiber whose end faces facing each other with a predetermined gap 17 coated with the antireflection coating. The tip part including this end face and the sealing part at one end? The protective tube is fitted into a heat conductive protective tube with a slight distance between the compound semiconductor reflective tube and the inner surface of the sealed portion of the protective tube.

[Effect]

In this invention, since the compound semiconductor anti-reflection film faces the original fiber anti-reflection film across a predetermined gap, the light incident from the optical fiber is transmitted through the original fiber anti-reflection film and the original fiber anti-reflection film.
It passes through the gap, the anti-reflection coating of the compound semiconductor, and the compound semiconductor, is reflected by one reflective element in the compound, and passes through the compound semiconductor, the anti-reflection coating of the compound semiconductor, the gap, and the anti-reflection coating of the original fiber to the optical fiber. incident.

[Embodiments of the invention]

FIG. 1 is a sectional view showing an embodiment of the present invention.
+II n +61 is completely (b)- different from the above-mentioned conventional temperature sensor. ulJn Anti-reflection film temporarily attached to the end face of the above optical fiber; 1), 112! The above compound semiconductor (anti-reflection coating coated with VC?fi on one of the parallel surfaces of 21, +
1 Country C The above compound semiconductor, a reflective hood attached to the other parallel surface of 21, 04 the above compound semiconductor (a ring spacer that holds 21, 01'ilH the above compound semiconductor 121 bonded to this ring spacer) , US is a predetermined gap placed at ldj between the antireflection film dυ and the antireflection film 1I21.

In the temperature sensor configured as described above, an antireflection film (Ill, tm gap u
e, antireflection film U21. The compound semiconductor (219 anti-reflection 1.!: film 1121 + gap 11 B1 passes through the anti-reflection film UU and passes through the original fiber 111 at the light receiving part (not shown). When the likelihood of a predetermined wavelength distribution is transmitted through the compound semiconductor (21), the temperature of the compound semiconductor (2) due to the heat conducted outside of the compound semiconductor (21) , and undergoes modulation that transmits light with a wavelength longer than that wavelength.In the optical receiving section, the compound semiconductor (2) is transmitted back and forth through the compound semiconductor (2) and modulated in response to its temperature?Based on the received intensity, the compound semiconductor (2) ) protection tube +51
To measure the temperature of external heat, the antireflection film 1121 of the optical fiber... and the compound semiconductor (21) are separated by a predetermined gap j
Since the reflective film u31 of 1 and the inner surface of the sealing part of the protective tube 1i1 are slightly separated, there is no damage due to mutual contact, and there is almost no change in the size of the gap tte or its refractive index due to temperature, and there is no reflection. Since the pattern 31 is coated with 121vC of compound semiconductor, highly accurate temperature measurement can be performed.

FIG. 2 is a sectional view showing another embodiment of the present invention.
The optical fiber III with the anti-reflection film dυ coated on the end face is inserted into the protective tube from the lower end to form the anti-reflection film and the reflective film u31. The compound semiconductor 21, which is attached to parallel surfaces and held by a ring spacer 1I41, is inserted from the upper end of the protection tube 12υ and the sealing lid 2f5? Attach the upper end of the protective tube with adhesive 0.
It can make the assembly work easier.

[The fruit of invention]

As explained above, this invention consists of a compound semiconductor whose absorption edge wavelength changes depending on the temperature, and an antireflection film of this compound semiconductor, in which a reflective film is coated on one side of the parallel planes, and the absorption edge wavelength of the compound semiconductor changes depending on the temperature. and a predetermined gap? 1. A sealing portion is placed at one end of the optical fiber, which has an anti-reflection film coated on its opposite end surface. The inside of the thermally conductive protective tube with V
Since the compound semiconductor reflective film and the inner surface of the sealing part of the protective tube are slightly spaced apart from each other, it is extremely strong! There is an advantage that highly accurate measurements can be made without any factors that may cause problems.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing one embodiment of this invention, and Figure 2 is another embodiment of this invention. A sectional view shown. FIG. 3 is a sectional view showing the main parts of a conventional temperature sensor. In the figure, +II Irf optical fiber, (21 is a compound semiconductor, ・5) is a protection tube, anti-reflection coating, +J21
1'f reflective anti-city film, 131 reflective film, (ring spacer at 141, adhesive part at 151, gap at f161, 125
The symbol is a protection tube, and the symbol is a sealing lid. 271 is an adhesive. Note that the 1cij- symbol in each figure indicates a portion corresponding to the same 1-span.

Claims (1)

[Claims] A compound semiconductor with an anti-reflection film coated on one parallel surface and a reflective film coated on the other, whose absorption edge wavelength of transmitted light changes depending on the temperature, and the anti-reflection film of this compound semiconductor facing each other with a predetermined gap. A tip portion including the end surface of an optical fiber whose end surface is covered with an antireflection film is inserted into a thermally conductive protective tube having a sealing portion at one end, and the reflective film of the compound semiconductor and the protective A temperature sensor characterized in that the inner surface of the sealed portion of the tube is slightly spaced apart.