WO1982001588A1

WO1982001588A1 - Temperature measuring apparatus

Info

Publication number: WO1982001588A1
Application number: PCT/JP1981/000318
Authority: WO
Inventors: Denki Kk Mitsubishi
Original assignee: Shinnishi Toshio; Tai Shuichi; Hamanaka Koichi; Kyuma Kazuo
Priority date: 1980-11-04
Filing date: 1981-11-04
Publication date: 1982-05-13
Also published as: JPS5779417A

Abstract

Temperature measuring apparatus using the material whose light transmittancy depends on temperature. This apparatus uses either light having a first wavelength at which the transmittancy depends on temperature when passing through a temperature sensor (9) and light having a second wavelength at which the transmittancy is constant with no relation to temperature, or two lights having first and second wavelengths at which the transmittancies change differently from each other depending on temperature. The ratio of the signal showing the intensity of the light of the first wavelength after passing through the temperature sensor (9), to the signal showing the intensity of the light having the second wavelength is obtained for measurement. Thus, it is possible to obtain a temperature measuring apparatus with high accuracy, since the output is not influenced even though the coupling efficiency between the optical fibers and the temperature sensor and the propagation losses in the optical fibers change. The invention is suitable for a temperature measuring apparatus with a low and middle temperaturerange in environments including high voltage, high magnetic fields, a chemical atmosphere, and others.

Description

Akira 细

Name of the invention

Temperature measuring device

Technical field

-This invention relates to a temperature measuring device, in particular, to a temperature measuring device using a material whose light transmittance changes with temperature.

Background art

Conventionally, there has been a device of this type shown in FIG. In the figure, (1) is composed of a light source, (2) and (4) are optical fibers, and (S) is composed of a semiconductor crystal or an amorphous body such as GaAs. The temperature sensor is a photoelectric conversion device. The transmittance of a temperature sensor to light varies with the wavelength of the light and with temperature. Fig. 2 is a characteristic diagram showing an example of the relationship between the wavelength dependence of the temperature sensor and the temperature. The horizontal axis represents the wavelength, the vertical axis represents the transmittance, and the parameters represent the parameters. It is expressed using the temperature Ti. At wavelengths ₂ , ₂ , and ₃ , the transmittance changes according to the change in temperature Ti.

There Well, the light source (1) if the work length of the light you Ke at you instead of the λ ₂ of the second view temperature ^ pressurized et al Τ ₃ or in the range that will change with temperature

O PI The light transmittance of the sensor changes. If the intensity of light incident on the optical fiber ( ² ) from the light source (1) is constant, the intensity of the light incident on the photoelectric conversion device ( ⁵ ) can be measured. Thus, the light transmittance of the temperature sensor ( ³ ) can be calculated, and thus the temperature of the temperature sensor (3) can be determined. Since the measuring device is configured as described above, the coupling efficiency between the optical fiber * (2), the temperature sensor (3), and the optical fiber ( ⁴ ) When the transmission loss of the optical fiber changes and the amount of light incident on the photoelectric conversion device (5) changes, the change due to the change and the temperature change of the temperature sensor. However, there was a drawback that it was not possible to distinguish between changes in the amount of incident light. When an LED (Light Emitting Diode) or LD (Laser Diode) is used as the light-emitting element of the light source, these are used. The light-emitting element of the present invention has a drawback in that the emission wavelength is changed by the change in temperature, and the transmittance of the temperature sensor is also changed by that. The invention of the opening excludes the disadvantages of the coming ones as described above. A light source having two lights with different wavelengths is used, and one of the wavelengths is used as a signal light, and the other is used as a reference light. Accordingly, it is an object of the present invention to provide a temperature measurement device capable of removing an error due to a change in coupling efficiency or the like.

According to this invention, the first wavelength light whose transmittance depends on temperature when passing through a temperature sensor, and the transmittance is constant irrespective of temperature. After passing through the temperature sensor using the light of the second wavelength or the light of the first and second wavelengths whose transmittance changes differently with respect to temperature. The ratio between the signal representing the intensity of the light of the first wavelength and the signal representing the intensity of the light of the second wavelength is obtained, whereby the connection between the optical fiber and the temperature sensor is obtained. Synthetic efficiency-Even if the transmission loss of the optical fiber changes, it does not affect the output, and it is possible to obtain a temperature measuring device capable of performing highly accurate measurement.

Brief explanation of drawings

FIG. 1 is a configuration diagram showing an example of a conventional temperature measuring device, and FIG. 2 is a characteristic diagram showing an example of the relationship between the depression length dependence of the temperature sensor shown in FIG. 1 and the temperature. Figure S is a block diagram showing one embodiment of the temperature measuring device of the present invention.

OMPI WIPO FIG. 4, FIG. 4 is a cross-sectional view showing an enlargement of the temperature sensor portion of FIG. S, FIG. 5 is a waveform diagram showing the output of the pulse generator of FIG. 3, and FIG. FIG. S is a characteristic diagram showing an example of the relationship between the wavelength dependence of the temperature sensor and temperature, and FIGS. 7 and 8 are block diagrams showing another embodiment of the present invention. , Fig. 9 is a waveform diagram showing the output of each part in Fig. 8, Fig. 10 to Fig. 15 are diagrams showing the relationship between the temperature sensor material and the optical fiber, and Fig. 16 is used. FIG. 3 is a characteristic diagram showing the relationship between the spectral distribution of light and the wavelength dependence of a temperature sensor and the temperature.

The same reference numerals in the figures indicate the same or corresponding parts. Best mode for carrying out the invention

An embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing one embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 indicate the same or equivalent parts, and (la), (lb) ) is, respectively Re its light-emitting element driving circuits, (6a), (6b) is, respectively Re its Mizunoto optical device) is an optical coupler, (8a), ⁽⁸ b) is, respectively Re its light off § ( ⁹ ) is a temperature sensor, and is a light receiving element. The light-receiving element 0 is a drawing of the input section of the photoelectric conversion device ( ⁵ ), and the photoelectric conversion device ( ⁵ ) includes the photoelectric conversion device light-receiving element shown in FIG.

Ο ΡΙ The thing is displayed. (L la), (l lb ) are, respectively Re its scan I Tsu switch ^{circuitry, (l 2 a), (} 12b) is, respectively Re its smooth circuits, (13a) (13b) is, respectively Re its Fig. 4 is a cross-sectional view showing an enlarged part of the temperature sensor ( ⁹ ) in Fig. 3, and is the same as Fig. 3. Symbols indicate the same parts, and) indicates a semiconductor crystal or an amorphous body such as GaAs, and indicates an adhesive.

FIG. 5 is a waveform diagram showing the output of the pulse generators (13a) and (13b) in FIG. 3, and FIG. 5 (a) shows the output of the pulse generator (13a). FIG. 5 (b) shows the output voltage of the pulse generator (13b).

FIG. 6 is a characteristic diagram showing an example of the relationship between the wavelength dependence of the temperature sensor ( ⁹ ) and the temperature, and is represented by a display method similar to that of FIG. There is.

Your name, eg if as the temperature cell down support material ^(3), can and Ru physicians use the GaAs or CdTe is, is a light emitting element () A ^ Ga s-based LED, scan ₂ = 0. 8.8 A'm, InGa AsP LED for the light-emitting element (6b), ₄ = 1.27 m, Ge-APD for the light-receiving element ^ should be used. However, APD is not a light receiving diode. The following describes the operation of the circuit shown in Fig. S.

OMPI 0 To jar you wonder if FIG. 6 monthsゝAkira Luo et al., Light of wavelength λ ₂ is you transmittance change of the temperature was down support ⁽⁹⁾ to come and that will change in the range of temperature force Τ! ~ Τ ₃ but the light-emitting element light of wavelength in the embodiment shown in FIG. 3 transmittance do not want to change the temperature was down service even if the temperature changes ⁽⁹⁾ (6a) is a wavelength lambda ₂ of light - emitting then, the light-emitting element (Sb) chooses to Let 's you emit light of wavelength λ _4. In this specification, λ _{2 is referred} to as a first depression length, and λ _{4 is referred} to as a second wavelength. The voltage shown in FIG. 5 (a) is applied to the light emitting element driving circuit (la) to cause the light emitting element (6a) to emit light, and the light emitting element driving circuit (lb) is applied to the light emitting element driving circuit (lb) as shown in FIG. 5 (b). The light-emitting element (6b) emits light by applying the indicated voltage. The light of wavelength λ _{2 from} the light emitting element (6a) passes through the optical fiber (8a), and the light of wavelength λ _{4 from} the light emitting element (6b) passes through the optical fiber (8b). ) And are combined by the optical coupler () and incident on the optical fiber ( ² ).

If the light emitting element driving circuits (la) and (lb), the light emitting elements (6a) and (6b), the optical fibers (8a) and (8b), and the optical coupler (?) Are integrated into a light source, This charge source generates light of the first wavelength and light of the second wavelength in a time-division manner, and can be incident on the optical fiber. The emitted light passes through an optical fiber (2), a temperature sensor (9), and an optical fiber (4).

οι 、:? ι The light is incident on the light receiving element 0, is converted into a voltage signal, is amplified by the photoelectric conversion device ( ⁵ ), and is input to the switch circuits (11a) and (lib). (11a) and (lib) are controlled in synchronization with the light emitting element drive circuits () and (6b) with the pulses shown in Figs. 5 (a) and (b), respectively. , scan I latch circuit (11a) or colleagues Outputs only the voltage signal that corresponds to the wavelength ₂ light force>', scan I latch circuit (lib) force> et al corresponding to light of a wavelength lambda ₄ only the voltage signal you, respectively Re its the output of the output to that is et al smoothing circuit (12a), by Ri smoothing, respectively Re its a DC voltage _VA _2, ν λ4 and in (12b) if, arithmetic unit you Outputs voltage that is proportional to _{_{_{V () = VA 2 a 4}}} . In this specification, VA _{2 is referred} to as a first voltage signal, and VA _{4 is referred} to as a second voltage signal.

As described above, the light of wavelength λ ₄ does not change its intensity depending on the temperature even after passing through the temperature sensor ( ⁹ ), and the light of wavelength λ ₂ has the temperature of λ _2. The strength changes depending on the temperature of the sensor ( ⁹ ). In addition, the transmission loss of the optical fiber is changed by the temperature sensor ( ⁹ ) depending on the coupling efficiency of the optical fiber (, (4) and the semiconductor crystal (3) and the bending). Therefore, the intensity of both the light of the wavelength and the light of the wavelength ^ changes almost the same, so that the arithmetic operation (V> = ₂ no, _{4 by} the arithmetic unit (½>) and the signal If v ₀ is output, the signal V is output. Is a signal from which fluctuations in output due to changes in the coupling efficiency of the temperature sensor are eliminated.

Figures 7 and 8 show other examples. In FIG. 7, the light emitted from the pulse generators (13a) and (13b), the light emitting element drive circuits (la) and (lb), and the light emitted from the light emitting elements (6a) and (6b) are coupled to the optical coupler ( ⁷ ) And sent to the temperature sensor ( ⁹ ) via the light 7 fiber ( ² ). In the temperature sensor ( ⁹ ), as in the case of FIG. 3, the light of wavelength λ ₂ changes its transmission intensity depending on the temperature, but the light of Dr. light is the light of you that are found transparent etc. does O to sail no relationship to temperature, and through the light off § I server (4), you separate the light of the wavelength λ ₂ of light and妓長λ ₄ It is led to the duplexer ¾. The light having the length λ ₂ is converted into an electric signal by the light receiving element (22a) of the photoelectric conversion device (5a) through the optical fiber (21a), and the light having the wavelength is converted into the optical fiber. After amplifying those signals that are converted into electric signals by the light receiving element (22b) of the photoelectric conversion device (5a) through the bus (21b), they are converted into DC signals by the smoothing circuits ²³ ) and (12b). Then, if Vo = ⁷ λ / ヽ⁷ is obtained by the arithmetic unit, the output signal V is obtained. Is a signal from which fluctuations in output due to changes in the integration rate of the temperature sensor have been removed.

Ο ΡΙ WIPO Next, FIG. 8 is explained. In the figure, the output voltages from the pulse generators ( _13a ) and (isb) are shown as waveforms in which the horizontal axis represents time t, as shown in Fig. 9. , And has a pulse width of τ ₂ and is delayed by _{3 in} time. As in the case of Figs. 3 and 7, these pulses are converted to optical pulses by the light emitting element driving circuit (la) (lb) and light emitting element (ea) (6b). After being confined by an optical coupler, it is guided to a temperature sensor by an optical fin (2). In its tail temperature was down service, Toru逼光the intensity of the light of wavelength λ ₂ is changed Tsu by the temperature, the transmitted light intensity of the wavelength ^ is not such changes etc. does O to sail One by the temperature. These lights are guided by an optical fiber (4) to a light-receiving element ^, where they are photoelectrically converted, then amplified, and sample-and-hold (2 ^ 3) ( 24b). Sa down pull-ho Lumpur de circuits (24a) (24b) is, Pulse generator (l ³ a) (13b) your good beauty service down the pull-Pulse onset generation circuits (25a) (25b ) Tsu by the in to Tsu by the Sakura the service down pull-Nono ⁰ Le vinegar, etc. Mr. its Re respectively length, the Pulse signal that corresponds to the skill length of the optical field Le vinegar height To a DC signal. Is input a DC signal of this is found in the _{_{^{calculator, V 0 = VA 2 / /}}} V; if Re fit seek, Figure 3, in the case of FIG. 8 and Similarly, the signal is a signal from which fluctuations in output due to changes in the coupling efficiency of the temperature sensor and the like have been removed.

In order to prevent a change in the light emission wavelength due to a temperature change of the light emitting elements (6a) and (6b), the light emitting elements (6a) and (6b) are provided with a peltier element or a heater. And keep the temperature constant.

Or, the light emitting element ⁽⁶ a), the temperature of the (Sb) and motor two motor, its is found in only the change in temperature, the arithmetic unit output V. May be corrected in an analog or digital manner.

In the embodiment shown in FIGS. 6, 7 and 8, the temperature sensor ( ⁹ ) is sandwiched between the optical fiber ( ² ) and ω, and is fixed with the adhesive ^. As a result, the dimensions can be made extremely small, making the structure suitable for measuring the temperature of minute parts.

As the temperature sensor ( ⁹ ), various structures other than those shown in FIG. 4 can be considered. Fig. 10 shows two optical fibers and a material such as a semiconductor. ^ Is an adhesive that is held by a jig such as an S6, and a high-temperature adhesive is suitable. Fig. 11 shows an optical fiber and a semiconductor. Insert micro lenses (27a) and (27b) between the materials such as

OMPI This is a reduction in optical coupling loss.

Further, in the embodiment shown in FIGS. 3, ⁷ , and ⁸ , the light having the wavelength λ _{2 and} the light having the wavelength ^ are generated in a time-division manner, but the method shown in FIG. Therefore, even if the light of wavelength 2 and the light of wavelength λ ₄ are continuously generated together, the same effect can be obtained.

In the embodiment shown in FIGS. 3, 7, and 8, the optical fiber that guides light from the light source to the temperature sensor section and the transmitted light from the temperature sensor> Although two optical fibers were required for the optical fiber that leads to the optical fiber, a configuration using one optical fiber, *, can be used. . FIG. 12 is a block diagram showing an embodiment of this method, in which ( ² ) is an optical fiber corresponding to that of FIG. 3, and (S) is an optical fiber of FIG. ( ³ ) is a semiconductor crystal, ( ⁴ ) is an optical fin corresponding to (4) in FIG. S, * is a beam splitter, and na is an optical fiber. Iva, ^ is a reflector, and is a plate. The device in the stage before the optical fiber ( ² ) and the device in the stage after the optical fiber ( ² ) are shown in FIG. S, FIG. 7 or FIG. 8, respectively. Same as the ones, but not shown in Figure 12

Optical fiber, * The device in the previous stage of ( ² ), the optical fiber Two

The case where the device shown in FIG. 3 is used as the device at the later stage will be described.

As shown in FIG. 3, light having wavelengths λ ₂ and λ ₄ , which have similar light source powers, is incident on an optical fiber ( ² ), and a beam splitter, an optical fiber. After passing through the semiconductor crystal (), it is reflected by the reflector ^, passes again through the semiconductor crystal (3) and the optical fiber, and forms a beam splitter ^. Itaru Ri Ru are better reflected the direction of light off § Lee bar ^(4). I was wanted third less incident Shako out of light off a Lee bar ⁽⁴⁾ on the light-receiving element 0 of FIG. 3 with FIG. The temperature of the temperature sensor ( ⁹ ) can be known using the same circuit as that described above. ^ The plate is provided to facilitate the transfer of heat to the semiconductor crystal. Therefore, the time constant of the thermal conduction of the temperature sensor (9) becomes smaller than that of the copper plate ^, and the response to the temperature change becomes faster.

When the devices shown in FIGS. 7 and 8 are used as the device at the stage before the optical fiber ( ² ) and the device at the stage after the optical fiber ( ⁴ ), it is also possible to use the devices shown in FIGS. Same as _c

FIG. 13 is also a structural example of the temperature cell down service that will be for feces real旌例of Figure 12 shows the in Ah Ru - Is et al, the I ⁴ diagram, shown in FIG. 15 Sea urchin, reflector

(OS) reflected light or processed into prism

_ΟΜΡΙ Utilizing the reflected light from the semiconductor crystal, it separates the optical fiber ( ² ) that guides the light to the temperature sensor and the optical fiber ω that guides the reflected light to the photoelectric conversion circuit. You can also. Fig. 14 shows an example using a single-core optical fiber, and Fig. 15 shows an example using a band-f フ ilino ^.

Further, in the above embodiment, an example is shown in which the semiconductor crystal (3) is used for the temperature sensor ( ⁹ ), but the temperature sensor ( ⁹ ) is not limited to a semiconductor crystal or an amorphous body. Any material can be used if the transmittance of light changes with temperature. In Fig. 6, the two types of light used are lasers. Forces on a single spectrum object, such as light; those with a spectrum width, such as a light-emitting diode It is okay. The relationship in this case is shown in the characteristic diagram of Fig. 1'6. : Indicates the spectral distribution of light. In this case, the integrated value of the transmittance (λ _: Τ) of the semiconductor crystal with respect to the wavelength and the spectral intensity Ρ () of the light source, ie, That is,

Is the transmitted light intensity. Here, T is temperature, λ is wavelength, and I (Τ) is transmitted light intensity.

Further, in the above embodiment, the transmittance of light of wavelength λ ₂ is

OMPI

Cao ⁰ 4 We have described the case where the light of wavelength λ ₄ changes with temperature and is transmitted almost independently of temperature, but the light of wavelength λ ₄ is almost independent of temperature. transmission required rather than, if the change in the characteristic transmission characteristic is one different in pairs to the temperature of the wavelength lambda ₂ of light and lambda ₄ light, and have use the appropriate signal processing circuits, the exact temperature the value of in also Oh Ru temperature Ru but One that-out in intellectual or Ri wavelength λ ₄ of light transmittance is changed in Tsu by the temperature there is and this ing to a predetermined value

If known, it is possible to know the temperature of the temperature sensor based on a predetermined value.

Furthermore, in the above embodiment, a light source such as a light emitting diode laser is assumed, but it is not necessary to limit to such a light source, for example, a halogen light source. be out Ri collected by the light source or we wavelength λ ₂ of the light and the wavelength λ ₄ of light Do you yo of down-flop have use an optical bus down de path full Note1 not good.

Industrial applicability

It can accurately and safely measure the temperature at low and medium temperatures in environments such as high voltage, high magnetic field, and chemical atmosphere, and can control large power equipment such as transformers and generators. It is essential for measuring abnormalities, quality assurance, and optimal design. It measures the winding and iron core in its operating state.

OMPI WIPO Suitable

Claims

Range of request

1. a temperature sensor constructed using a material provided in the light path of the optical fiber and having a light transmittance that varies as a function of the wavelength and temperature of the light; The light having the first wavelength whose transmittance changes with temperature and the second wavelength are light having a second wavelength whose transmittance varies differently with temperature. A light source to be generated, and light from the light source passing through the temperature sensor via an optical fiber, and a light component having the first wavelength of the light passed through the temperature sensor. Means for outputting a first voltage signal corresponding to the first voltage signal and a second voltage signal corresponding to the light component of the second wavelength and i, respectively, and the first voltage signal A temperature measuring device comprising: a computing unit for receiving the second voltage signal and calculating a ratio of the two inputs.

2. The light source that emits light having the first and second wavelengths is a light source that emits light having the first wavelength, in which the light transmittance of the temperature sensor changes depending on the temperature. The temperature measurement according to claim 1, wherein the temperature measurement generates light having a second wavelength whose transmittance does not change with temperature.

CMPI WIPO

3. The light source that emits light having the first and second wavelengths is the light having the first wavelength that varies depending on the temperature and the light transmittance power of the temperature sensor. The above-mentioned transmittance changes with temperature and generates light having a second wavelength different from the first wavelength in temperature with respect to the above-mentioned transmittance. The temperature measuring device according to claim 1, which is a claim.

4. Output a first voltage signal corresponding to the light component of the first wavelength and a second voltage signal corresponding to the light component of the second wavelength, respectively. The means includes: means for generating, in a light source, the light of the first wavelength and the light of the second wavelength in a time-division manner with each other; and inputting the light having passed through the temperature sensor. And a photoelectric conversion device that outputs a voltage signal corresponding to the intensity of the light that has been input, and separates the output of the photoelectric conversion device in synchronization with time division in the light source. The temperature measuring device according to any one of claims 1 to 3, which is characterized in that the temperature measuring device is provided with a switch circuit.

5: The first voltage signal corresponding to the light component of the first wavelength and the second voltage signal corresponding to the light component of the second wavelength are separately output. The means of temperature

O PI WIPO 8

An optical demultiplexer that separates the first and second wavelengths of light that have passed through the optical demultiplexer, and the first and second wavelengths that are separated and output from the optical demultiplexer. Claim 1. Claim 1 in which the first and second photoelectric conversion devices which input light respectively and output voltage signals corresponding to the intensity of the input light respectively are included. Or a temperature measuring apparatus according to any one of section S.

6. Means for separately outputting the voltage signal of (1) corresponding to the light component of the first wavelength and the second voltage signal corresponding to the light component of the second wavelength, respectively. Means for generating, in a light source, the light of the first wavelength and the light of the second wavelength in a time-division manner with each other; and inputting the light passing through the high-frequency sensor. Sampler that separates the output of the photoelectric conversion device of the photoelectric conversion device, which outputs a voltage signal corresponding to the intensity of the input light, in synchronization with the time division of the light source. The temperature measuring device according to any one of claims 1 to 3, which is characterized in that the temperature measuring device is equipped with a temperature circuit.

7. The temperature sensor is constructed by attaching a material whose light transmission rate changes as a function of the depth of light and temperature as a function of the adhesive to the end face of the optical fiber. Be happy to enjoy

O PI The temperature measurement device described in Item 1.