JP5835650B2 - Temperature measuring device and Seebeck coefficient calculation method - Google Patents

Description

  The present invention relates to a temperature measurement device and a Seebeck coefficient calculation method.

  2. Description of the Related Art Conventionally, temperature measuring devices that measure the temperature of an object to be measured using a thermocouple are known (for example, Patent Documents 1 and 2). A temperature measuring device using a thermocouple is a thermoelectromotive force generated by a temperature difference from a cold junction that is the other junction point of a thermocouple, with a hot junction that is one junction point of the thermocouple being in contact with or close to the object to be measured. ΔV10 (Seebeck effect) is measured. At the same time, the temperature t1 of the cold junction is measured by a temperature sensor (temperature sensing element, thermistor, etc.) as cold junction temperature measuring means. Then, from the Seebeck coefficient S stored in the nonvolatile memory, the thermoelectromotive force ΔV10, and the temperature t1 of the cold junction, a temperature t2 of the hot junction that is the temperature of the object to be measured is obtained (t2 = (ΔV10 + S × t1). ) / S)

  The Seebeck coefficient S varies depending on the material and shape of the thermocouple, and the Seebeck coefficient S corresponding to the thermocouple is stored in the nonvolatile memory of the apparatus.

  When the thermocouple deteriorates due to use over time (oxidation, change in metal structure, etc.), the characteristics of the thermocouple change and the Seebeck coefficient S changes. As a result, the Seebeck coefficient stored in the non-volatile memory is different from the Seebeck coefficient of the thermocouple used, and there is a problem that good temperature measurement cannot be performed over time.

  Further, conventionally, when replacing a deteriorated thermocouple, it is necessary to prepare a thermocouple having the same Seebeck coefficient S, and there is a problem that the convenience is poor.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a temperature measurement device and a Seebeck coefficient calculation method capable of performing good temperature measurement over time and improving convenience. Is to provide.

  In order to achieve the above object, the invention of claim 1 includes a thermocouple, cold junction temperature measuring means for measuring the temperature of the cold junction of the thermocouple, an output value of the thermocouple, and the cold junction temperature measurement. In the temperature measurement device for measuring the temperature of the measurement object based on the measurement result of the means and the Seebeck coefficient, the heating means for heating the cold junction, the cold junction is heated by the heating means, and the temperature of the cold junction Detecting the output value of the thermocouple at a first temperature and the output value of the thermocouple at a second temperature different from the first temperature, and detecting the thermocouple at the first temperature and the first temperature. It comprises a Seebeck coefficient calculating means for calculating the Seebeck coefficient based on the output value of the pair, the second temperature, and the output value of the thermocouple at the second temperature.

According to the present invention, the first temperature, the thermocouple output value when the cold junction temperature is the first temperature, the second temperature, and the thermocouple output value when the cold junction is the second temperature. Based on this, the Seebeck coefficient is calculated. When the output value (thermoelectromotive force) of the thermocouple when the temperature of the cold junction is the first temperature is ΔV1, the following equation is established.
ΔV1 = S × (t2−t1a) (1)
The t1a is the first temperature of the cold junction, and the t2 is the temperature of the hot junction (measurement object).
Further, when the output value (thermoelectromotive force) of the thermocouple when the temperature of the cold junction is the second temperature is ΔV2, the following equation is established.
ΔV2 = S × (t2−t1b) (2)
The t1b is the second temperature of the cold junction.
Since ΔV1, ΔV2, t1a, and t1b are known, the Seebeck coefficient S can be obtained by solving the simultaneous equations of the above equations (1) and (2). Further, the temperature t2 of the measurement object can also be obtained by solving the simultaneous equations of the above equations (1) and (2). Thereby, the Seebeck coefficient S at the time of measuring the temperature of the measurement object can be obtained. As a result, the temperature t2 of the measurement object can be obtained from the Seebeck coefficient S when the thermocouple changes with time and the characteristics change, and a highly accurate temperature measurement can be performed. In addition, even if the Seebeck coefficient S of the thermocouple to be replaced is different from the Seebeck coefficient S of the thermocouple before replacement, the temperature t2 of the measurement object can be measured with high accuracy, and the convenience of the apparatus is improved. it can.

  According to the present invention, even when the thermocouple changes with time and the characteristics change, the temperature of the measurement object can be measured well. Moreover, the thermocouple of a different Seebeck coefficient can be exchanged, and the convenience of the apparatus can be enhanced.

The schematic block diagram of the sheath part of the temperature measuring device of this embodiment. The schematic block diagram of the temperature measurement part of the temperature measuring device. The schematic block diagram of the board | substrate of the same temperature measurement part. The control block diagram of a temperature measuring device. The characteristic view which shows the temperature change of the phase change material in a time transition, and the resistance change of the cold junction temperature measurement part. The characteristic view which shows the temperature change with respect to the electric current which flows through a cold junction temperature measurement part when heating a phase change substance, and the resistance value change of a cold junction temperature measurement part. The graph which shows the resistance value-temperature characteristic of a cold junction temperature measurement part. A timing chart of temperature calibration, Seebeck coefficient calculation, and temperature measurement of a measurement object. The flowchart of temperature calibration, Seebeck coefficient calculation, and temperature measurement of a measurement object. The schematic plan view of the board | substrate with which the cold junction of the temperature measuring apparatus of the modification 1 was provided. The schematic plan view of the board | substrate with which the cold junction of the temperature measuring apparatus of the modification 2 was provided. AA sectional drawing of FIG. The schematic plan view which shows an example of the board | substrate with which the cold junction of the temperature measuring apparatus of the modification 3 was provided. The schematic plan view which shows the other example of the board | substrate with which the cold junction of the temperature measuring apparatus of the modification 3 was provided. BB sectional drawing of FIG. The characteristic view which shows the temperature change with respect to time transition in two phase change substances of a different phase transition temperature. 10 is a timing chart of temperature calibration of a temperature measuring device according to Modification 3. The flowchart of the temperature calibration of the temperature measuring apparatus of the modification 3, Seebeck coefficient calculation, and the temperature measurement of a measuring object. The graph which shows the resistance value-temperature characteristic of a cold junction temperature measurement part. The schematic plan view of the board | substrate with which the cold junction of the temperature measuring apparatus of the modification 4 was provided. The control block diagram of the temperature measuring device of the modification 4. The figure explaining the mechanism which electrically detects the flow (viscosity) change of a phase change substance when a phase changes. The figure explaining the other structural example of the mechanism which electrically detects the flow (viscosity) change of the phase change substance at the time of a phase change. The figure explaining the further another structural example of the mechanism which electrically detects the flow (viscosity) change of the phase change substance at the time of a phase change. The schematic plan view of the board | substrate with which the cold junction of the temperature measuring apparatus of the modification 5 was provided. DD sectional drawing of FIG. FIG. 10 is a control block diagram of a temperature measuring device according to Modification 5. 10 is a timing chart of temperature calibration of a temperature measuring device according to Modification 5. The flowchart of the temperature calibration of the temperature measuring device of the modification 5, Seebeck coefficient calculation, and the temperature measurement of a measuring object.

Hereinafter, an embodiment of a temperature measuring device to which the present invention is applied will be described.
1 is a schematic configuration diagram of the sheath portion 101 of the temperature measuring device 100, FIG. 2 is a schematic configuration diagram of the temperature measuring portion 110 of the temperature measuring device 100, and FIG. 3 is a substrate 1 of the temperature measuring portion 110. FIG.
The temperature measuring apparatus 100 includes a sheath part 101 having a hot junction of a thermocouple and a temperature measuring part 110 having a cold junction. As shown in FIG. 1, the sheath portion 101 of the temperature measuring device 100 includes a thermoelectric device having a hot junction W in which a first thermoelectric material 103 a and a second thermoelectric material 103 b are joined in a metal protective tube 102 (sheath tube). It has a pair 103 and is filled with an inorganic substance 104 such as ceramic at high pressure. The end 113 a of the first thermoelectric material 103 a and the end 113 b of the second thermoelectric material 103 b of the thermocouple 103 are exposed from the metal protective tube 102.

  As shown in FIG. 2, the temperature measurement unit 110 includes the substrate 1 shown in FIG. 3, which includes a base material 2 and an electrical insulating layer 3 in a main body case. The substrate 1 has a first connection electrode 10 made of the same thermoelectric material as the first thermoelectric material 103a of the thermocouple 103 and a second thermoelectric material made of the same thermoelectric material 103b as the second thermoelectric material 103b of the thermocouple 103. The connection electrode 11 is provided. The first connection electrode 10 and the second connection electrode 11 extend to substantially the center of the substrate 1, and are made of a conductive material such as a metal material such as Al, Ni, Si, and the signal processing circuit unit 20. It joins with the circuit connection electrode 7 to connect, and forms a pair of cold junction C of a thermocouple.

  Between the cold junction of the 1st connection electrode 10 and the cold junction of the 2nd connection electrode 11, the cold junction temperature measurement part 5 as a cold junction temperature measurement means which measures the temperature of a cold junction, and temperature calibration The phase change material 6 is arranged symmetrically with the two-dot chain line A in the figure as a reference line and symmetrical with the two-dot chain line B as a reference line. Thus, by arranging the cold junction temperature measuring unit 5 and the phase change material 6 symmetrically between the pair of cold junctions, the temperature of the pair of cold junctions can be measured with high accuracy.

  The cold junction temperature measurement unit 5 is a resistor having temperature dependency such as Pt, NiCr, SiC, C, and the temperature is detected by obtaining a resistance value of the resistor by the signal processing circuit unit 20. Moreover, in this embodiment, it has a function as a heating means which heats the cold junction temperature measurement part 5 which consists of this resistor, and heats the phase change material 6.

  The phase change material 6 which is a standard material for temperature calibration is a material that undergoes phase transition in a narrow temperature range with high reproducibility and high accuracy. Before and after the phase transition, temperature (heat), electrical resistance value, heat capacity, viscosity (flow) Property), mass, natural frequency, and dielectric constant. In the present embodiment, the phase change of the phase change material 6 is detected by detecting the change. The phase change material 6 may be any material that undergoes a phase transition at a certain temperature. In particular, it is preferable to use a substance showing a temperature determined as an international temperature scale in which the temperature is determined with high accuracy, because calibration can be performed with high accuracy. Further, as the phase change substance 6, it is preferable to select conditions and materials that undergo a reversible phase transition with good reproducibility between solid and liquid, liquid and gas, and the like. As a result, temperature calibration can be performed at any time, and temperature measurement can be performed with accuracy maintained at any time. In order to calibrate with high accuracy, it is preferable to use the phase change material 6 having a phase transition temperature close to the temperature to be used. Alternatively, paraffin or sodium acetate may be used as the phase change material 6 and temperature calibration may be performed based on the supercooling temperature at a known temperature.

  When detecting changes in (thermal), viscosity (fluidity) and natural frequency of the phase change substance 6 to detect a phase change in the phase change substance 6, the following materials can be preferably used. That is, Ga: 29.7646 ° C., In: 156.5985 ° C., Sn: 231.928 ° C., Zn: 419.527 ° C., Al: 660.323 ° C., Ag: which are defined fixed points of the international temperature scale ITS-90 961.78 ° C., Au: 1064.18 ° C., Cu: 1084.62 ° C., and the like. These materials are preferable because their melting points (freezing points) are particularly highly accurate. Further, Bi: 271.3 ° C. and alloys such as Sn—Zn, Sn—Ag, and Bi—Sn alloy can be melted at a specific temperature upon heating in the range of 130 ° C. to 170 ° C. depending on the mixing ratio.

Moreover, when detecting the phase transition of the phase change material 6 by a change in mass or heat capacity, the oxides such as Bi ₂ O ₃ , In ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , and P ₂ O ₅ are Since the phase transition from a solid to a gas is performed in a known narrow temperature range, it is preferable because changes in mass and heat capacity at the phase transition temperature can be detected well.

Moreover, when detecting the phase transition of the phase change material 6 by a change in electrical conductivity, V ₂ O ₅ that is also used in a CTR thermistor is preferable. V ₂ O ₅ is a monoclinic semiconductor having a negative temperature coefficient when it is lower than the phase transition temperature (80 ° C.) at which phase transition occurs due to the structural change of the crystal. When the transition temperature (80 ° C.) is exceeded, a rutile structure / tetragonal system is obtained, and the electrical conductivity increases by two orders of magnitude (resistance decreases rapidly). Therefore, when the phase transition of the phase change material 6 is detected by a change in electric conductivity, the phase transition of the phase change material 6 can be detected well by using V ₂ O ₅ as the phase change material 6. it can. A PTC thermistor mainly composed of barium titanate is also suitable. When the PTC thermistor exceeds the Curie temperature, the crystal system undergoes a phase transition from the tetragonal system to the cubic system, and accordingly, the electrical resistance value rapidly increases. Thus, by using a material that causes a change in electrical conductivity accompanying a change in crystallinity at a known phase transition temperature as the phase change material 6, the phase transition of the phase change material 6 can be changed by a change in electrical conductivity. It can be detected well.

When the phase transition of the phase change material 6 is detected by a change in dielectric constant, when the phase transition of the phase change material 6 is optically detected, and when it is detected by a change in natural frequency, the phase change As the substance 6, potassium tantalate niobate (KTa1-xNbxO ₃ ) can be suitably used. Potassium tantalate niobate undergoes a structural phase transition of the crystal at the phase transition temperature, the dielectric constant and the second-order electro-optic constant (Kerr constant) are maximized, and the natural frequency is around the phase transition temperature (35.6 ° C). Changes rapidly. Therefore, when the phase change of the phase change material 6 is detected as a change in dielectric constant, when the phase change of the phase change material 6 is detected optically, and when a change in the natural frequency is detected, the phase change By using potassium tantalate niobate (KTa1-xNbxO ₃ ) as the substance 6, the phase transition of the phase change substance 6 can be detected well.

The base material 2 of the substrate 1 is made of a conductive material such as a metal material such as Al, Ni, or Si. The electrical insulating layer 3 undergoes a phase transition if it is lower than the phase transition temperature of the phase change material 6. Therefore, it is necessary to select a material having a phase transition temperature higher than that of the phase change material 6. SiO ₂ , Si ₃ A heat resistant material such as N ₄ or Al ₂ O ₃ is used. In the present embodiment, the first and second connection electrodes 10 and 11, the cold junction temperature measuring unit 5, and the phase change material 6 are formed on the electrical insulating layer 3 formed on the base material 2 made of a conductive material. However, when the base material 2 is made of an electrically insulating material such as glass or ceramic, the first and second connection electrodes 10 and 11, the cold junction temperature measuring unit 5, and the phase change are formed on the base material 2. Substance 6 or the like may be provided.

The electrical insulating layer 3 is formed by CVD, sputtering, sol-gel method, and various thin film manufacturing methods. The first and second connection electrodes 10 and 11, the cold junction temperature measuring unit 5, the circuit of the signal processing circuit unit 20, and the like are pattern-formed on the electrical insulating layer 3 by photolithography. Further, the conductivity of the cold junction temperature measuring unit 5, the first and second connection electrodes 10 and 11, the circuit of the signal processing circuit unit 20, the liquefied fluidity accompanying the phase transition of the phase change material 6, and the ambient atmosphere It is preferable to protect the member by appropriately covering the member with the electrical insulating layer 3 in consideration of the chemical reaction with the material. For example, if the cold junction temperature measuring unit 5 or the phase change material 6 is heated to a high temperature by heating the phase change material 6 and the surface is oxidized or corroded by the ambient atmosphere, the durability is improved. In addition, the cold junction temperature measuring section 5 and the entire phase change material are covered with a heat-resistant oxide or nitride electrical insulating layer 3 to be inactivated (passivation). Specifically, in the case of the phase change material 6 such as a metal material, if the phase change material 6 is exposed on the surface, the phase change material 6 may be changed to a metal oxide by the ambient atmosphere, and the phase transition temperature may change. Further, when the phase change material 6 is liquefied, the temperature distribution may change due to flow deformation. As a result, reproducibility may not be obtained when the phase transition is repeated. Therefore, in order to prevent the phase change material 6 from being chemically changed by the ambient atmosphere, the phase change material 6 is passivated by the electrical insulating layer 3 so as not to contact the ambient atmosphere, or the flow when the phase change material 6 is liquefied. In order to prevent deformation, the phase change material 6 is surrounded by the electrical insulating layer 3. Further, when calibration is performed with high accuracy using a definition fixed point of the international temperature scale, it is necessary to detect the freezing point (melting point) of the phase change material 6 under standard atmospheric pressure (10.325 Pa). As described above, the phase change material 6 has a heat-resistant structure by covering the heat-resistant electrical insulating layer 3 made of a heat-resistant material such as SiO ₂ , Si ₃ N ₄ , and Al ₂ O ₃ . The inside of the electrical insulating layer 3 is maintained at a constant pressure. Thereby, even if the atmospheric pressure of the surrounding atmosphere changes, the phase change materials 6A and 6B are not affected and the accuracy of temperature calibration described later can be increased.

  Further, when a pattern is formed on the electrical insulating layer 3 by a photo-etching technique for semiconductor microfabrication, the stacking step affects the processing dimension accuracy. Accordingly, when the cold junction, the cold junction temperature measurement unit 5 and the phase change material 6 are arranged apart from each other, they are arranged in parallel on the same plane. Thereby, a lamination | stacking level | step difference can be made small and an accuracy variation can be made small. Further, there is a gap between the cold junction temperature measurement unit 5 and the phase change material 6, the cold junction temperature measurement unit 5 and the phase change material 6 are electrically insulated, and the phase change material 6 has conductivity. Even so, the electrical influence on the cold junction temperature measurement unit 5 can be eliminated.

  As shown in FIGS. 2 and 3, a region 22 (hereinafter referred to as a measurement region) in which a cold junction C, a phase change material 6, and a cold junction temperature measurement unit 5 formed in the electrical insulating layer 3 of the base material 2 are provided. The portion opposite to the above is removed by an etching process to form a cavity 21. As a result, the cold junction C, the cold junction temperature measurement unit 5 and the measurement region 22 of the electrical insulating layer 3 on which the phase change material 6 is formed are not in contact with the base material 2. The heat capacity in the vicinity of the change substance 6 can be reduced. As a result, the phase change material 6 can be heated quickly by generating heat in the cold junction temperature measurement unit 5. Further, since the heat capacity of the measurement region is small, the temperature response of the cold junction temperature measurement unit 5 can be made sharp, and the temperature of the cold junction C and the temperature of the phase change material 6 can be measured with high accuracy.

  As shown in FIG. 2, the case 111 of the temperature measurement unit 110 has a connection port 111 a on the socket in which the sheath unit 101 can be inserted and removed from the temperature measurement unit 110. Further, a pressure leaf spring 112 is provided at a location of the case 111 facing the connection portions 10a and 10b of the first and second connection electrodes. The pressing plate spring 112 has an abutting portion 112a against which the end portion 113a of the first thermoelectric material of the thermocouple inserted from the connection port 111a and the end portion 113b of the second thermoelectric material abut, and the first and second portions. It has the pressurization part 112b which pressurizes the surface on the opposite side to the connection part 10a, 10b of the 1st and 2nd connection electrode of the edge parts 113a and 113b of a thermoelectric material.

  The case 111 is provided with a slide knob 114 that is slidable with respect to the case 111. The slide knob 114 is provided with a pressing protrusion 114a that abuts the pressing plate spring 112 and presses the pressing plate spring 112 toward the substrate.

  When the end portion 113a of the first thermoelectric material and the end portion 113b of the second thermoelectric material of the thermocouple are inserted into the connection port 111a of the case 111, the end portions 113a and 113b of the first and second thermoelectric materials are formed. The end portion 113a of the first thermoelectric material is opposed to the connection portion 10a of the first connection electrode, and the end portion 113b of the second thermoelectric material is opposed to the connection portion 10a of the second connection electrode. Opposing to the connecting portion 11a. Next, when the slide knob 114 is slid to the right side in the drawing, the pressing protrusion 114a of the slide knob 114 comes into contact with the pressure plate spring 112 and presses the pressure plate spring 112 to the substrate side. When the pressing plate spring 112 is pressed by the pressing protrusion 114a, the pressing plate spring 112 is bent toward the substrate side, and the pressing portion 112b of the pressing plate spring is connected to the first and second connection of the first and second thermoelectric materials. Pressure is applied to the electrode connection and the surface opposite to the facing surface. Thereby, the end portion 113a of the first thermoelectric material is in contact with the connection portion 10a of the first connection electrode, and the end portion 113b of the second thermoelectric material is in contact with the connection portion 11a of the second connection electrode, The sheath part 101 is fixed to the temperature measurement part 110.

  When removing the sheath part 101 from the temperature measurement part 110, the slide knob 114 is slid to the left side (sheath part side) in the figure to move the end portions 113a and 113b of the first and second thermoelectric materials to the substrate side. The pressurization is released, and the end portions 113a and 113b of the first and second thermoelectric materials can be easily extracted from the connection port 111a.

Moreover, if the base material 2 is Si, it is easy to integrate each circuit of the signal processing circuit unit 20. For example, SiO ₂ is formed on the surface by thermally oxidizing the Si base material, or a single layer or multiple layers of SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ or the like is formed on the Si base material 2 by CVD or sputtering. The electrical insulating layer 3 is formed. Next, after forming the polysilicon layer and the oxide film, impurity diffusion regions to be the circuits of the cold junction temperature measuring unit 5 and the signal processing circuit unit 20 are formed in the polysilicon layer using the oxide film as a mask. Next, an Al (aluminum) circuit connection electrode 7, first and second connection electrodes 10, 11 and a phase change material 6 are formed on the electrical insulating layer 3 by CVD, sputtering, a sol-gel method, and various thin film manufacturing methods. A pattern is formed by photolithography. In this case, peripheral circuits can be integrated in the same chip as a CMOS device structure by the same Si base material 2, electrical insulating layer 3, polysilicon layer, oxide film and wiring material. When using a substrate having an SOI (Si On Insulator) structure, the BOX layer is used as the electrical insulating layer 3 and an impurity diffusion region serving as a circuit of the cold junction temperature measuring unit 5 and the signal processing circuit unit 20 is formed in the SOI layer. . Next, the circuit connection electrode 7, the first and second connection electrodes 10, 11, the phase change material 6 and the like are formed on the BOX layer by CVD, sputtering, sol-gel method, and various thin film manufacturing methods, and patterned by photolithography. In this way, peripheral circuits can be integrated in the same chip as a CMOS device structure by the Si base material 2, the BOX layer, and the SOI layer.

  Control programs such as a program for performing temperature calibration of the cold junction temperature measurement unit 5 provided in the circuit of the cold junction temperature measurement unit 5 and the signal processing circuit unit 20 and a program for performing temperature measurement by a thermocouple are stored. The storage memory (P-ROM) may be a phase change storage memory (Ovonic Unified Memory) made of the same material as the phase change material 6. This phase change memory stores information by transitioning a crystalline phase to an amorphous phase by rapid thermal change. Specifically, a crystalline state or an amorphous state is created by controlling the temperature and time when the phase change material constituting the phase change memory is cooled by heating with a heater. When in the crystalline state, the electrical resistance value is low, and when in the amorphous state, the electrical resistance is high. Information can be read out using the difference in electrical resistance value. The phase change memory may also be used for a storage unit such as a register. Thus, by using the phase change memory made of the same material as the phase change material 6 as the storage memory of the signal processing circuit unit 20, the phase change unit and the storage memory of the signal processing circuit unit 20 are simultaneously patterned. The manufacturing process can be simplified.

  Further, as shown in FIG. 3, a through hole 9 is provided around a measurement region 22 where the cold junction C, the cold junction temperature measurement unit 5, and the phase change material 6 of the electrical insulating layer 3 are provided. Thereby, it can suppress that the heat at the time of heating the phase change material 6 in the cold junction temperature measurement part 5 propagates to other than a measurement area | region, and can heat the phase change material 6 efficiently.

  In addition, the signal processing circuit unit 20 includes an interface, a control circuit, a register, ΔΣ A / D, a transmission circuit, and the like for measuring the temperature of the measurement object based on the output value of the thermocouple. Further, terminals such as an address input terminal, a GND terminal, a clock input terminal, a data input / output terminal, and a power input terminal are provided at the left end of the substrate 1 in the drawing. For example, as shown in FIG. 2, the terminal 8 is connected to a power source, an external device, or the like via a wiring wire 12 and a lead pin 13. Thus, by forming the signal processing circuit unit 20 on the same substrate as the substrate provided with the cold junction C, the wiring length for transmitting the signal from the cold junction temperature measuring unit 5 and the thermocouple to ΔΣ A / D is shortened. In addition, the temperature of the cold junction C can be measured with high accuracy and is less susceptible to noise.

FIG. 4 is a control block diagram of the temperature measuring apparatus 100.
The signal processing circuit unit 20 functions as a temperature calibration unit that performs temperature calibration of the cold junction temperature measurement unit 5, detects the thermoelectromotive force of the thermocouple 103, and measures the temperature of the measurement object 30. A function for calculating the Seebeck coefficient of the pair 103 is included.
As shown in FIG. 4, the signal processing circuit unit 20 includes a power supply 201 and an oscillation circuit 208 for applying an AC bias to the cold junction temperature measurement unit 5. Also, a resistance value detection unit 202 for detecting the resistance value of the cold junction temperature measurement unit 5, a register 203 as a storage means for storing the phase transition temperature and the resistance value of the cold junction temperature measurement unit 5 at that time, an object to be measured A thermoelectromotive force voltage detector 204 for measuring 30 temperatures, a ΔΣ A / D converter 205 for converting an analog signal into a digital signal, and a Seebeck coefficient calculation as a Seebeck coefficient calculation means for calculating a Seebeck coefficient S. Based on the circuit 206, the Seebeck coefficient S, the temperature of the cold junction C, the thermoelectromotive force, and the like, a temperature conversion unit 207 that measures the temperature of the measurement object, a control circuit 209 that controls each circuit, and the like are included.

  When a calibration execution signal is input from the control circuit 209 to the power supply 201, the cold junction temperature measurement unit 5 as a heating unit generates heat. At the same time, the resistance value of the cold junction temperature measurement unit 5 is calculated by the resistance value detection unit 202, and the time and the resistance value of the cold junction temperature measurement unit 5 are stored in the register 203. Then, the phase transition of the phase change material 6 is detected based on the resistance value of the cold junction temperature measurement unit 5, and the resistance value of the cold junction temperature measurement unit 5 at that time is used as the known phase transition temperature of the phase change material 6, and the temperature dependence Is obtained and stored in the register 203.

  When a temperature measurement execution signal is input from the control circuit 209 to the power supply 201, the resistance value of the cold junction temperature measurement unit 5 is calculated by the resistance value detection unit 202, and the calculated resistance value and the previous temperature dependence are calculated. Is output to the temperature conversion unit 207 as a cold junction temperature measurement value. Further, the thermoelectromotive force detected by the thermoelectromotive force voltage detection unit is output to the temperature conversion unit. The temperature conversion unit 207 obtains a temperature difference between the hot junction and the cold junction based on the Seebeck coefficient S calculated by the Seebeck coefficient calculation circuit described later and the thermoelectromotive force. Next, the temperature of the hot junction temperature (measurement object) is obtained based on the temperature difference between the obtained hot junction and the cold junction and the cold junction temperature measured by the cold junction temperature measurement unit 5, and the temperature measurement value is obtained. As output.

When a signal for execution of Seebeck coefficient calculation is input from the control circuit 209 to the power supply 201, the cold junction temperature measurement unit 5 as a heating unit generates heat, and the cold junction temperature is heated to a predetermined first temperature. To do. The resistance value of the cold junction temperature measurement unit 5 is calculated by the resistance value detection unit 202, and the cold junction temperature is calculated and calculated using the calculated resistance value and the relational expression indicating the temperature dependence. When the cold junction temperature reaches the first temperature, the thermoelectromotive force voltage detector 204 detects the thermoelectromotive force of the thermocouple 103. Next, the cold junction temperature measuring unit 5 as a heating unit is caused to generate heat, and the cold junction temperature is heated to a second temperature different from the predetermined first temperature. Next, when the calculated cold junction temperature becomes the second temperature, the thermoelectromotive force voltage detection unit 204 detects the thermoelectromotive force of the thermocouple 103. Then, the relationship of the following equation (a) obtained from the first temperature t1a and the thermoelectromotive force ΔV1 at this time, the relationship of the following equation (b) obtained from the second temperature t1b and the thermoelectromotive force ΔV2 at this time The Seebeck coefficient S is calculated from the simultaneous solution with the equation.
ΔV1 = S × (t2−t1a) (a)
ΔV2 = S × (t2−t1b) (b)
The t2 is the temperature of the hot junction W.

Next, the principle of calibration using the phase transition of the phase change material in the temperature measurement apparatus 100 of the present embodiment will be outlined. Here, the case where the phase transition of the phase change material is detected by the temperature (heat) change of the phase change material will be described.
FIG. 5 is a characteristic diagram showing the temperature change of the phase change material over time and the resistance change of the cold junction temperature measurement unit 5. As shown in FIG. 5, when the phase change material 6 is heated and the phase change material 6 reaches the phase transition temperature (melting point (freezing point): Mpa), an endothermic reaction occurs. If the phase change material is solid, it begins to become liquid at the phase transition temperature as the temperature rises, maintains the phase transition temperature MPa during the period when everything is liquid, and rises again after all becomes liquid. To do. Therefore, a portion where the electric resistance value of the cold junction temperature measuring unit 5 tends to be discontinuous appears. That is, as shown in FIG. 5, when the electrical resistance value R2 of the cold junction temperature measurement unit 5, it can be determined that the temperature is the phase transition temperature. Therefore, the temperature value of the cold junction temperature measuring unit 5 which is a temperature-dependent resistor is measured, and temperature calibration is performed with the temperature when the measured resistance value becomes the resistance value R2 as the known phase transition temperature. Do. Thus, the relationship between the phase transition temperature and the electric resistance value is a one-to-one relationship, and calibration can be performed by using this relationship.

  The time point of phase change can be detected more accurately by reducing the heat capacity of the heating part (in this embodiment, the cold junction temperature measuring part 5) for heating the phase change material 6 and forming it in a uniform temperature region. . In the present embodiment, the cold junction temperature measuring unit 5 is used as a heating means for heating the phase change material 6. When the phase change material 6 is heated, a large current that causes Joule heat in the cold junction temperature measurement unit 5 is passed through the cold junction temperature measurement unit 5. As shown in FIG. 5, when the phase change material 6 undergoes a phase transition from a solid to a liquid, the phase change material 6 exhibits an endothermic reaction, and since the temperature does not change from the start to the end of the phase change, the temperature is maintained. The increasing tendency of the electrical resistance value of the resistor which is also the temperature measuring unit 5 changes to a parallel state. The time of the endothermic reaction (the time during which the temperature does not change) is increased as the amount of heat of transition (latent heat) of the phase change material 6 is large and the ratio of the heat capacity of the phase change material 6 to the heat capacity of the entire detection region is large. This is preferable because the phase displacement of the phase change material 6 can be reliably detected. The resistance value detection unit of the signal processing circuit unit 20 calculates the electrical value of the cold junction temperature measurement unit 5 at time T0 from the voltage value applied to the cold junction temperature measurement unit 5 and the current value flowing through the cold junction temperature measurement unit 5. The resistance value and the electrical resistance value of the cold junction temperature measurement unit 5 at time T1 are stored as transition data. Then, a function (linear function: R = aT + b) of the resistance value R and the time T is calculated from the electric resistance value at the time T0 and the electric resistance value at the time T1. The resistance value after time T1 obtained by this function is compared with the measured resistance value R after time T1. Then, after time T2, data that does not fit the function is generated, and it can be detected that the phase change material 6 has undergone phase transition.

When the phase transition of the phase change material 6 is detected, the electrical resistance value R2 of the cold junction temperature measurement unit 5 is stored in the memory as the known temperature Mpa, and the relational expression showing the temperature dependence as shown in FIG. 7 is corrected. When the cold junction temperature measurement unit 5 measures the cold junction temperature, a weak current is supplied to the cold junction temperature measurement unit 5 so as not to generate Joule heat, and the electric power of the cold junction temperature measurement unit 5 at that time is supplied. Measure the resistance value. Then, by using the relational expression indicating the temperature dependence as shown in FIG. 7 and the known resistance temperature coefficient TCR of the cold junction temperature measurement unit 5 stored in the memory, the resistance of the cold junction temperature measurement unit 5 is determined. The temperature is detected from the value.
Relational expressions showing temperature dependence shown in FIG. 7: (resistance value R, temperature S, temperature coefficient (TCR) α
R = R0 * (1 + α * S) (Formula 1)
For example, when the temperature measuring unit is a platinum resistor, the temperature coefficient (TCR) α is α = 3.9083E-03 (0 ° C. to 850 ° C.).
In the temperature calibration, R0 is corrected based on the relationship between the resistance value R2 and the temperature MPa.

In addition, since the accuracy required for practical use of the temperature of the present embodiment is sufficient in the range of 0 to 850 ° C. and ± 0.1 ° C., the relational expression β × S2 indicating the temperature dependence of the following equation is expressed. Although a linear function that is linear as 0 is used as a relational expression that indicates temperature dependence, a relational expression that indicates the temperature dependence of a quadratic function shown in the following expression may be used. By using the relational expression showing the temperature dependence of the quadratic function shown in the following formula, an accuracy of ± 0.01 can be obtained in the range of 0-419.527 ° C., and the accuracy of the resistance value-temperature characteristic is further increased. It can also be increased.
R = R0 * (1 + α * S + β * S2) (formula)
For example, the temperature coefficient (TCR) of the platinum resistor is α = 3.9083E-03, β = −5.7750E-07 (0 ° C. to 850 ° C.)

  FIG. 6 is a characteristic diagram showing a temperature change with respect to a current passed through the cold junction temperature measurement unit 5 and a resistance value change of the cold junction temperature measurement unit 5 when the phase change material 6 is heated. FIG. 6 is an example in which the phase change material 6 undergoes a phase change from liquid to gas, and is an example in which phase transition is detected by a change in heat capacity. As shown in FIG. 6, when the value of the current flowing to the cold junction temperature measurement unit 5 is increased and the boiling point Bp is reached, the phase change material 6 undergoes phase transition. When the phase change material 6 undergoes a phase transition from liquid to gas at a known temperature (sublimation point or boiling point: Bp), the phase change material 6 appears as a discontinuous characteristic that does not increase in temperature due to endothermic reaction until transpiration is completed. However, since the mass of the phase change material 6 decreases due to transpiration, the discontinuous characteristics that do not increase in temperature are so short that they do not appear in FIG. For this reason, when the phase change material 6 undergoes a phase change from a liquid to a gas, it is possible to detect a discontinuous characteristic in which the temperature does not increase due to an endothermic reaction, as in the case where the phase change material 6 undergoes a phase change from stationary to liquid. difficult. Therefore, when the phase change material 6 undergoes a phase change from liquid to gas, the phase transition temperature is detected based on the difference between the temperature increase before transpiration and the temperature increase after transpiration. Specifically, when the phase change material 6 evaporates, the heat capacity around the temperature measurement unit in the detection region decreases by the amount of the phase change material. As the heat capacity decreases due to the transpiration of the phase change material, the temperature rise and the increase (slope) of the cold junction temperature measurement unit 5 become larger than before the phase change material 6 evaporates, as shown in FIG. Since the temperature (electrical resistance value) appears remarkably as a discontinuous characteristic, this discontinuity start point (the rear end in a region where the temperature does not rise very slightly) is detected. Therefore, also in this case, the function (primary function: R = aT + b) of the electrical resistance value R and time T of the cold junction temperature measurement unit 5 is calculated from the data obtained immediately after the phase change material heating, and fits to this function If no data is generated, it can be detected that the phase change material 6 has undergone phase transition. When the phase transition of the phase change material 6 is detected, the electrical resistance value R2 of the cold junction temperature measurement unit 5 is stored in the memory as a known temperature Mpa. When the cold junction temperature measurement unit 5 measures the cold junction temperature, a weak current is supplied to the cold junction temperature measurement unit 5 so as not to generate Joule heat, and the electric power of the cold junction temperature measurement unit 5 at that time is supplied. Measure the resistance value. As described above, the temperature of the cold junction is calculated using the relational expression indicating the temperature dependence corrected by the temperature calibration.

FIG. 8 is a timing chart of temperature calibration, Seebeck coefficient calculation, and temperature measurement of the measurement object, and FIG. 9 is a flowchart.
When a predetermined period elapses, the control circuit 209 outputs a calibration execution signal. When a calibration execution signal is output (YES in S1), the electrical resistance value R2 of the cold junction temperature measurement unit 5 at the phase transition temperature MPa detected in the previous calibration stored in the register 203 is deleted. (S2). Next, the power supply 201 for applying a bias to the cold junction temperature measurement unit 5 is activated (S3), the heating current Ic for heating the phase change material is applied to the cold junction temperature measurement unit 5, and the phase change material 6 is Heated. Further, the resistance value detection unit 202 detects the voltage value Vc to calculate a resistance value, and the calculated resistance value is stored in the register 203. Further, a difference value ΔR is calculated from the calculated resistance value and the resistance value calculated immediately before this (S5).

  As shown in FIG. 8, at time T <b> 2, the phase change material 6 undergoes a phase change, and the difference value (time differentiation) ΔR = 0 of the resistance value R of the cold junction temperature measurement unit 5. The control circuit 209 checks whether or not the calculated ΔR is 0 (S6). If the difference value ΔR is 0 (YES in S6), the control circuit 209 sets the calculated resistance value to the electrical resistance value Ra of the cold junction temperature measuring unit 5 at the phase transition temperature MPa (S7), and the phase transition. Based on the electrical resistance value Ra of the cold junction temperature measuring unit 5 at the temperature MPa, a function of temperature dependence is obtained and stored in the register 203 (S8). Then, the application of the heating current to the cold junction temperature measurement unit 5 is turned off, and the temperature calibration is completed.

  Thus, in this embodiment, the cold junction temperature measurement unit 5, the resistance value detection unit 202, and the control circuit 209 constitute a phase transition detection unit, and the control circuit 209 constitutes a temperature calibration unit.

  When the temperature calibration is completed, a flag is set and a signal for executing the Seebeck coefficient calculation is output from the control circuit 209 at the timing when the temperature of the cold junction returns to room temperature. With the passage of time, the Seebeck coefficient S of the thermocouple 103 varies as the first thermoelectric material 103a and the second thermoelectric material 103b are oxidized or the metal structure is changed. For this reason, when the same Seebeck coefficient S is used from the beginning, an error occurs in the temperature measurement value of the measurement object due to use over time. Therefore, the Seebeck coefficient S is calculated at a predetermined timing, and the Seebeck coefficient S corresponding to the deterioration state of the first thermoelectric material 103a and the second thermoelectric material 103b is calculated (S9).

  When a signal for executing the Seebeck coefficient calculation is output from the control circuit 209, the power supply 201 for applying a bias to the cold junction temperature measurement unit 5 is activated, and a heating current for heating the cold junction to the first temperature t1a is applied. Is done. A resistance value is calculated by the resistance value detection unit 202. Next, the cold junction temperature is calculated from the temperature dependency function and the calculated resistance value. When the calculated cold junction temperature is the first temperature t1a, the thermoelectromotive force voltage detector detects the thermoelectromotive force voltage value of the thermocouple and stores it in the register as ΔV1. Next, the heating current applied to the cold junction temperature measurement unit is increased to heat the cold junction to a second temperature t1b higher than the first temperature. Next, a resistance value is calculated by the resistance value detection unit 202, and a cold junction temperature is calculated from the temperature dependency function and the calculated resistance value. If the calculated cold junction temperature is the second temperature t1b, the thermoelectromotive force voltage detection unit 204 detects the thermoelectromotive force voltage value of the thermocouple and stores it in the register 203 as ΔV2. Then, the relational expression (a) is obtained from the first temperature t1a and the thermal electromotive force ΔV1 at this time, the relational expression (b) is obtained from the second temperature t1b and the thermal electromotive force ΔV2 at this time, The Seebeck coefficient S is calculated from the simultaneous solution of the above formulas (a) and (b), the calculated Seebeck coefficient S is stored in the register 203, and the Seebeck coefficient calculation process is completed.

  In addition, as shown in FIG. 8, the time (time T6-time T4) after starting control which makes a cold junction a 1st temperature until detecting a thermoelectromotive force when a cold junction is a 2nd temperature is 1.0 μsec, which is a very short time. Therefore, as shown in FIG. 8, when calculating the Seebeck coefficient, the temperature t2 of the hot junction is substantially the same temperature. Therefore, the Seebeck coefficient S can be calculated with high accuracy. Further, when it is desired to increase the accuracy, as shown in FIG. 8, the thermoelectromotive force ΔV1 at the first temperature t1a and the thermoelectromotive force ΔV2 at the second temperature t1b are detected again, and the values of the thermoelectromotive forces ΔV1 and ΔV2 are detected. It may be verified whether or not there is an error. If the error is greater than or equal to a predetermined value, ΔV1 and ΔV2 are detected again, and control for verifying whether or not the error with respect to the previous ΔV1 and ΔV2 is less than or equal to the predetermined value is repeatedly performed. If the error with respect to the previous ΔV1 and ΔV2 is equal to or less than a predetermined value, the Seebeck coefficient S may be calculated using the previous ΔV1 and ΔV2. Alternatively, ΔV1 and ΔV2 may be detected a plurality of times, and the Seebeck coefficient S may be calculated based on the average value.

When a temperature measurement execution signal of the measurement object is input to the control circuit 209 (S10), the power supply 201 for applying a bias to the cold junction temperature measurement unit 5 is activated (S11), and the cold junction temperature measurement unit 5 is activated. A detection current for detecting the temperature of the cold junction is applied to the cold junction, and the cold junction temperature is calculated from the temperature dependency function and the calculated resistance value, and is input to the temperature converter 207 (S12). Further, the thermoelectromotive force voltage detector detects the thermoelectromotive force of the thermocouple and inputs it to the temperature converter 207 (S13). The temperature conversion unit 207 calculates the temperature of the measurement object, which is the temperature of the hot junction, based on the calculated Seebeck coefficient S, the thermoelectromotive force, and the temperature of the cold junction (S14), and outputs it (S15). Specifically, assuming that the temperature t1 of the cold junction and the thermoelectromotive force ΔV, the temperature t2 of the hot junction (measurement object) can be obtained by the following equation.
t2 = (ΔV + St1) / S (c)

  In the present embodiment, since the Seebeck coefficient S is calculated at a predetermined timing, even if the thermocouple deteriorates with time and the Seebeck coefficient S changes, temperature measurement with high accuracy can be performed. In the present embodiment, as shown in FIG. 2, the sheath part 101 is detachable from the temperature measurement part 110. When the size and length of the thermoelectric material of the sheath portion 101 are different, the Seebeck coefficient S is different, but in this embodiment, the Seebeck coefficient S is calculated. Even if it is attached to the device, it is possible to perform highly accurate temperature measurement. Thereby, according to a use, the temperature measurement part 110 can be mounted | worn with the sheath part 101 from which the length and magnitude | size of a thermocouple differ, and a temperature measurement can be performed, and the convenience improves. Specifically, when the sheath part 101 having a different Seebeck coefficient from the sheath part 101 previously attached to the temperature measurement unit 110 is attached, the Seebeck coefficient S is calculated to calculate the Seebeck coefficient S. The calculation of the Seebeck coefficient S at this time may be performed manually, or a detection unit that detects attachment / detachment of the sheath portion 101 is provided, and when it is detected that the sheath portion 101 is attached, the calculation of the Seebeck coefficient S is performed. May be executed.

  In the present embodiment, the substrate 1 of the temperature measurement unit 110 is provided with portions (first connection electrode 10 and second connection electrode 11) that constitute a part of the thermocouple 103, and the first provided on the substrate 1. The first connection electrode 10 and the second connection electrode 11 are connected to the circuit connection electrode 7 to form a cold junction. However, in this case, it is necessary to use the sheath portion 101 of the same material as the first connection electrode 10 for the first thermoelectric material 103a and the same material as that of the second connection electrode 11 for the second thermoelectric material 103b. The sheath part 101 will be limited. Therefore, the end portion 113a of the first thermoelectric material of the sheath portion 101 and the end portion 113b of the second thermoelectric material are configured to be in direct contact with the circuit connection electrode 7, and the end of the first thermoelectric material of the sheath portion 101 is configured. The connection location between the portion 113a and the circuit connection electrode 7 and the connection location between the end portion 113b of the second thermoelectric material and the circuit connection electrode 7 may be cold junctions. By comprising in this way, the 1st thermoelectric material 103a of the sheath part 101 and the 2nd thermoelectric material 103b do not have a restriction | limiting, The sheath part 101 which can be used can be increased, and the convenience can be improved further. . Also in this case, since the Seebeck coefficient S is different if the first thermoelectric material and the second thermoelectric material of the sheath portion 101 are different from the thermoelectric material of the sheath portion that was previously mounted, the thermoelectric power of the sheath portion that was previously mounted is different. When the sheath part 101 using a thermoelectric material different from the material is attached to the temperature measurement part 110, the Seebeck coefficient S is calculated.

  Further, in the present embodiment, the calculation of the Seebeck coefficient and the temperature measurement of the measurement object 30 are separated, but only the Seebeck coefficient is obtained by solving the simultaneous equations of the above expressions (a) and (b). Instead, the temperature of the hot junction can be calculated. Therefore, the calculation of the Seebeck coefficient and the temperature measurement of the measurement target 30 may be performed simultaneously. However, in this case, it is necessary to heat the cold junction to the first temperature and detect the thermoelectromotive force at that time and the cold junction to the second temperature and detect the thermoelectromotive force at that time. It takes time until the temperature of the measurement object is output. However, since the temperature of the measurement object is calculated with the Seebeck coefficient corresponding to the deterioration state of the thermocouple at the time of measurement, highly accurate temperature detection can be performed. Thus, for example, a high accuracy mode for measuring temperature with high accuracy and a normal mode are provided, and when the high accuracy mode is selected, the cold junction is heated to the first temperature and the heat The electric power and the cold junction may be heated to the second temperature, the thermoelectromotive force at that time may be detected, and the Seebeck coefficient S and the temperature of the measurement object may be calculated.

  Further, in the present embodiment, when measuring the temperature of the measurement object 30, a detection current is applied to the cold junction temperature measurement unit 5 and the temperature of the cold junction at that time is detected. The temperature of the measurement object 30 may be measured by supplying a heating current to the temperature measurement unit and setting the cold junction temperature to a predetermined temperature. In particular, it is preferable to heat the cold junction to a temperature at which the phase change material 6 melts. This is because the resistance value of the cold junction temperature measurement unit 5 detected at that time is the temperature Mpa at which the phase change material undergoes a phase change, so that the cold junction temperature error can be substantially eliminated. Thereby, the temperature of the measurement object can be detected with high accuracy.

  In the present embodiment, the phase change material 6 is provided on the substrate 1 and the phase change material is heated to change the phase, and the output value (resistance value) of the cold junction temperature measurement unit 5 when the phase change occurs. Is performed with a known phase transition temperature, so that the temperature of the cold junction can be detected with high accuracy. As a result, the temperature of the hot junction (measurement object 30) can be accurately measured. In addition, since the temperature calibration of the cold junction temperature measurement unit 5 can be easily performed at any time, a highly accurate measurement result of the cold junction temperature can be maintained.

  Further, since the cold junction temperature measurement unit 5 can be calibrated, the signal processing circuit unit 20 can be provided on the cold junction temperature measurement unit 5 or the substrate 1 provided with the cold junction. In other words, conventionally, when integrated on one substrate including the signal processing circuit unit 20, there are many factors that affect the accuracy of the cold junction temperature measurement unit 5, and the variation range of the output value of the cold junction temperature measurement unit 5 is rather large. The temperature of the cold junction cannot be accurately measured. In addition, by manufacturing with special design measures and high-precision manufacturing conditions, variation in the detection results of the cold junction temperature measurement unit 5 can be suppressed, but the yield of products that pass the standard is reduced, and the cold junction The manufacturing cost is higher than the case where the provided substrate and the substrate provided with the signal processing circuit unit are provided separately. However, in this embodiment, even if there is a characteristic variation in each circuit of the signal processing circuit unit 20 and there is a variation in the output value of the cold junction temperature measurement unit 5, by performing the temperature calibration described above, The temperature of the cold junction can be accurately measured. In addition, since it is not necessary to manufacture under special design measures or high-precision manufacturing conditions, the signal processing circuit unit 20 can be integrated on the substrate provided with the cold junction, while suppressing the manufacturing cost. Further, by integrating the signal processing circuit unit 20 on a substrate provided with cold junctions, the wiring for connecting to each circuit of the signal processing circuit unit can be shortened, and the phase transition of the phase change material can be performed with high accuracy and less noise. In addition, the temperature of the cold junction and the temperature of the measurement object can be measured.

  Next, a modification of this embodiment will be described.

[Modification 1]
FIG. 10 is a schematic plan view of the substrate 1 provided with the cold junction C of the temperature measuring device 100A of the first modification.
As shown in FIG. 10, the humidity measuring device 100 </ b> A according to the first modification is provided with the cold junction temperature measuring unit 5 and the heating unit separately. As shown in the figure, the heating unit was arranged in parallel between the temperature measurement unit and the phase change material. In this figure, the signal processing circuit unit 20 is omitted.

  When performing temperature calibration, a heating current is applied to the heating unit to heat the phase change material, and a weak detection current is applied to the cold junction temperature measurement unit 5 to calculate a resistance value. ΔR is obtained as described above. Even when the Seebeck coefficient S is calculated, a heating current is applied to the heating unit to heat the cold junction, and a weak detection current is applied to the cold junction temperature measurement unit 5 to detect the cold junction temperature. To do.

  When the cold junction temperature measurement unit 5 is used as a heating means for melting the phase change material or a cold junction as the heating means for calculating the Seebeck coefficient S, a large current is applied to the cold junction temperature measurement unit 5. There is a need. As a result, the cold junction temperature measuring unit 5 is likely to change the resistance temperature coefficients α and β due to electromigration. Therefore, it is necessary to devise conditions such as the material and dimensions of the cold junction temperature measurement unit 5 and the coating of the passivation film on the surface of the heating unit, or to increase the frequency of temperature calibration in order to maintain accuracy. . However, by providing a heating unit separately from the cold junction temperature measurement unit 5, only a weak detection current flows through the cold junction temperature measurement unit 5, so that changes in the resistance temperature coefficients α and β can be suppressed. Even if the frequency of temperature calibration is low, the stability of the cold junction temperature measurement of the cold junction temperature measurement unit 5 can be maintained.

[Modification 2]
FIG. 11 is a schematic plan view of a substrate provided with the cold junction C of the temperature measuring device 100B according to Modification 2. FIG. 12 is a cross-sectional view taken along the line AA in FIG.
In the temperature measuring device 100 of the second modification, the phase change material 6 is laminated on a cold junction temperature measuring unit that heats the phase change material 6. If the phase change material 6 is a conductive material, as shown in FIG. 12, the electrical insulating layer 3 is provided on the cold junction temperature measuring unit 5, and the phase change material 6 is connected to the cold junction temperature measuring unit via the electrical insulating layer 3. Laminate.

  Also in this modified example 2, a portion of the base material 2 that faces the measurement region 22 is removed by an etching process to form the cavity 21. Further, a through hole 9 was provided around the measurement region 22. Thereby, it can suppress that the heat at the time of heating the phase change material 6 in the cold junction temperature measurement part 5 propagates outside the measurement region, and the phase change material 6 and the cold junction can be efficiently heated. it can.

  By laminating the phase change material 6 on the cold junction temperature measurement unit 5, the cold junction temperature measurement unit 5 that heats the phase change material 6 and the phase change material 6 are in close proximity, and the cold junction temperature measurement unit 5 and the phase Heat transfer with the change substance 6 is also equalized at equal distances. As a result, as shown in FIG. 3, the area where the phase change material 6 is arranged is reduced as compared with the case where the cold junction temperature measuring unit 5 for heating the phase change material 6 and the phase change material 6 are arranged in parallel. . Therefore, compared with the configuration shown in FIG. 3, the heat capacity of the measurement region 22 is reduced, and the thermal response speed of the measurement region is increased. As a result, temperature calibration can be performed quickly. In addition, the cold junction temperature measurement unit 5 and the cold junction can be arranged close to each other, and the temperature measurement accuracy of the cold junction can be increased. Further, the cold junction can be quickly heated to the predetermined first temperature and second temperature, and the Seebeck coefficient can be calculated quickly.

[Modification 3]
13 and 14 are schematic plan views of a substrate provided with the cold junction C of the temperature measuring device 100C according to the third modification. FIG. 15 is a sectional view taken along line BB in FIG.
In the temperature measuring device 100C of the third modification, different phase change materials 6A and 6B are dispersedly arranged in the vicinity of the cold junction temperature measuring unit 5 that heats the phase change material. In FIG. 13, the signal processing circuit unit 20 is provided on the substrate 1, and the phase change materials 6A and 6B are arranged in parallel near the cold junction temperature measurement unit.

  The substrate 1 shown in FIGS. 14 and 15 does not include the signal processing circuit unit 20, and two types of phase change materials 6 </ b> A and 6 </ b> B are stacked on the cold junction temperature measuring unit 5. Further, the substrate 1 shown in FIGS. 14 and 15 has a through hole 9 around the measurement region 22.

  The two types of phase change materials 6A and 6B are materials having different phase change temperatures. When the phase change materials 6A and 6B are in contact with each other, the phase change materials 6A and 6B diffuse to each other and change to a new alloy or compound, and the phase change temperature changes. Therefore, a plurality of phase change materials having different phase change temperatures are separated from each other. As described above, by using two kinds of phase change materials 6A and 6B having different phase transition temperatures, it is not necessary to store the resistance temperature coefficient TCR of the cold junction temperature measurement unit in the memory. Specific description will be given below.

  FIG. 16 is a characteristic diagram showing temperature changes with time in two phase change materials 6A and 6B having different phase transition temperatures, and FIG. 17 shows input / output signals of temperature calibration of the temperature measuring device 100C of the third modification. FIG. 18 is a timing chart, and FIG. 18 is a flowchart of temperature calibration, Seebeck coefficient calculation, and temperature measurement of the measurement target of the temperature measurement device 100C of the third modification.

  As shown in FIG. 18, when a calibration execution signal is output (S 21), the temperature dependence function stored in the memory is deleted (S 22), and the phase change material is stored in the cold junction temperature measurement unit 5. A heating current for heating is applied, and the phase change materials 6A and 6B are heated (S24). Then, as shown in FIG. 17, the temperature at which one phase change material 6A undergoes phase transition at time T2 (melting point (freezing point): Mpa, which is a known value unique to phase change material 6A). Further, when the heating current is continuously supplied and the temperature is raised, the temperature at which the other phase change material 6B undergoes phase transition at time T4 (melting point (freezing point), which is a known value unique to the phase change material 6B): Mpb (> Mpa ))become.

  Thus, when there are two types of phase change materials, the phase changes of the two types of phase change materials 6A and 6B are detected as follows. That is, until the phase transition from the solid to the liquid is completed, even if the applied power is increased by the endothermic reaction, the temperature does not increase and ΔR = 0. Therefore, at time T2, one phase change material 6A has a known phase transition temperature Mpa. Can be detected. Similarly, at time T4, it can be detected that the other phase change material 6B has reached a known phase transition temperature Mpb.

  In the same manner as described above, ΔR is calculated (S25), and whether or not ΔR is 0 is checked (S26). If ΔR becomes 0, the control circuit 209 sets the calculated resistance value to the phase transition temperature MPa. Is set to the electric resistance value Ra of the cold junction temperature measuring section 5 (S27). Further, when the heating current is increased and the endothermic reaction (ΔR = 0) is eliminated, and the resistance value of the cold junction temperature measurement unit 5 starts to increase, it is checked again whether ΔR = 0 (S28-). S30). When ΔR becomes 0, the control circuit 209 sets the calculated resistance value to the electric resistance value Rb of the cold junction temperature measuring unit 5 at the phase transition temperature MPb (S31).

  Next, as shown in FIG. 19, based on the electrical resistance value Ra of the cold junction temperature measurement unit 5 at the phase transition temperature MPa and the electrical resistance value Rb of the cold junction temperature measurement unit 5 at the phase transition temperature MPb, the temperature A dependency function is obtained and stored in a memory. Then, the application of the heating current to the cold junction temperature measuring unit 5 is turned off, and the temperature calibration is completed (S32). The subsequent flow for calculating the Seebeck coefficient and the flow for measuring the temperature of the measurement object are the same as described above, and a description thereof will be omitted.

  As described above, by performing temperature calibration using two different phase change materials 6A and 6B, a highly accurate temperature scale can be provided. In addition, since a temperature-dependent function is obtained, a resistor material having an unknown resistance temperature coefficient (TCR) can be used.

  Further, in order to obtain a more accurate measurement value, it is preferable that the phase transition temperature is as close as possible to the temperature detection range among the freezing points of the standard substances shown in the international temperature scale (ITS-90). For example, in an application corresponding to −40 to + 125 ° C., which is the measurement range of an IC temperature sensor used in general electronic equipment, the phase change material 6A includes In (Mpa = 156.5985 ° C.) and the phase change material 6B includes By selecting Sn (Mpb = 231.928 ° C.) and using Pt (linear at 0 ° C. to 850 ° C.) for the cold junction temperature measuring unit 5, high-precision measurement is possible even in a temperature range other than the range from Mpa to Mpb. A value can be obtained. In the third modification, 6A and 6B are used as two types of phase change substances. However, when a quadratic function is used as a relational expression indicating temperature dependence, temperature coefficients (TCR) α and β are not used. In addition, at least three different known phase transition temperatures are required to calculate a function indicating temperature dependence. In this case, three or more kinds of phase change materials having different phase transition temperatures may be provided.

  Further, in the above, a plurality of phase change materials 6A and 6B having different phase transition temperatures are configured not to be mixed, but each phase change material is brought into contact with each other to form a new alloy or compound. Temperature calibration may be performed at a known phase transition temperature of the alloy or compound. For example, In is selected for the phase change material 6A and Sn is selected for the phase change material 6B, an In—Sn alloy is formed, and the melting point (freezing point) is referred to the binary alloy phase diagram according to the mixing ratio of In and Sn. Can be obtained. Therefore, for example, a phase change portion made of In phase change material 6A, a phase change portion made of Sn phase change material 6B, and a phase change portion in which phase change material 6B is laminated on phase change material 6A, It is arranged in parallel in the vicinity of the cold junction temperature measuring unit 5. When temperature calibration is performed or in advance, the cold junction temperature measurement unit 5 is heated to melt the phase change material 6A and the phase change material 6B, and the phase change material 6B is laminated on the phase change material 6A. In the phase change portion thus formed, these two metals are mixed to generate a phase change material 6AB made of an In—Sn alloy. Thereby, three types of phase change materials having different phase transition temperatures from two types of materials can be formed on the substrate. Furthermore, since the mixing ratio of In and Sn changes depending on the ratio of the lamination thickness, and the phase change temperature changes, by providing a plurality of phase change portions having different thickness ratios of the phase change substances to be laminated, A large number of phase change portions having different phase transition temperatures can be formed.

[Modification 4]
FIG. 20 is a schematic plan view of a substrate provided with the cold junction C of the temperature measurement device 100D of the fourth modification, and FIG. 21 is a control block diagram of the temperature measurement device of the fourth modification.
The temperature measuring device 100D according to the fourth modified example makes the phase change material 6 conductive, and electrically detects changes in electrical characteristics such as resistance value change and capacitance change of the phase change material 6 when the phase change occurs. Thus, the phase change of the phase change material 6 is detected.

In the temperature measurement device 100D of the fourth modification, a pair of detection lead wires 16 are provided in the vicinity of the cold junction temperature measurement unit 5, and conduction of two different phase change temperatures is performed between the pair of detection lead wires. Sex phase change materials 6A and 6B are arranged in parallel, and connect between the detection lead wires 16.
As the phase change material, a material whose electric conductivity (resistance value) or electric capacity greatly varies upon phase transition such as V ₂ O ₅ is used.

  As shown in FIG. 21, the signal processing circuit unit 20 is the same as FIG. 4 except that the signal processing circuit unit 20 includes a detection unit 210 that detects a resistance value and a capacitance by passing a detection current through the detection lead wire. It is.

The temperature calibration of the cold junction temperature measurement unit 5 in the temperature measurement device 100D of the modification 4 is performed as follows.
First, a heating current is applied to the cold junction temperature measurement unit 5 to heat the phase change materials 6A and 6B. At the same time, a detection current is applied to the detection lead wire 16, and the resistance value is calculated by the detection unit 210. When the phase change material 6A undergoes a phase change, the electrical conductivity of the phase change material 6A changes abruptly, and the resistance value changes. Thereby, it can be detected that the phase change material 6A has undergone a phase change. When the phase change material 6A detects that the phase has changed, the resistance value of the cold junction temperature measurement unit 5 calculated by the resistance value detection unit 202 at this time is used as the cold junction temperature measurement unit 5 at the phase transition temperature MPa. Is set as the electrical resistance value Ra.

  Further, when the phase change material is heated by the cold junction temperature measurement unit 5, the phase change material 6 </ b> B undergoes a phase change, and the electrical conductivity of the phase change material 6 </ b> B changes abruptly and is calculated by the detection unit 210. The resistance value changes. Thereby, it can be detected that the phase change material 6B has undergone a phase change. When the phase change material 6B detects that the phase has changed, the resistance value of the cold junction temperature measurement unit 5 calculated by the resistance value detection unit 202 at this time is used as the cold junction temperature measurement unit 5 at the phase transition temperature MPb. Is set as the electrical resistance value Rb.

  That is, in the fourth modification, when the control circuit 209 detects that the time differential ΔRL of the resistance value detected by the detection unit 210 is equal to or greater than a predetermined value, the cold junction detected by the resistance value detection unit 202 is detected. The resistance value of the temperature measuring unit 5 is stored in the register 203 as the electric resistance value Ra of the cold junction temperature measuring unit 5 at the phase transition temperature MPa. When the control circuit 209 detects again that the time differential ΔRL of the resistance value detected by the detection unit 210 is equal to or greater than a predetermined value, the cold junction temperature measurement unit 5 detected by the resistance value detection unit 202 The resistance value is stored in the register 203 as the electric resistance value Rb of the cold junction temperature measurement unit 5 at the phase transition temperature MPb.

  Then, in the same manner as in Modification 3, based on the electrical resistance value Ra of the cold junction temperature measurement unit 5 at the phase transition temperature MPa and the electrical resistance value Rb of the cold junction temperature measurement unit 5 at the phase transition temperature MPb, the temperature A dependency function is obtained and stored in a memory. Then, the application of the heating current to the cold junction temperature measurement unit 5 is turned off, the detection current to the detection lead wire 16 is turned off, and the temperature calibration is completed.

  In the above, the change in electrical resistance at the time of phase change of the phase change materials 6A and 6B is detected to detect that the phase change materials 6A and 6B have changed phase. A change in electric capacitance may be detected to detect that the phase change materials 6A and 6B have changed phase.

Moreover, the phase change of the phase change material can also be detected by electrically detecting the flow (viscosity) change of the phase change material 6 when the phase changes.
FIG. 22 is a diagram illustrating a mechanism for electrically detecting a flow (viscosity) change of the phase change material 6 when the phase changes. In the figure, the phase change material 6 explains the shape change accompanying the flow (viscosity) change of the phase change material 6 accompanying the phase transition from solid to liquid.
As shown in FIG. 22A, when the phase change material 6 is in a solid state, the phase change material 6 is in contact with the detection leads 16a and 16b and is conductive. When the solid phase change material 6 reaches a known phase transition temperature due to heating of the cold junction temperature measuring unit 5, surface tension is generated by liquefaction and aggregates to the center as shown in FIG. Then, the phase change material 6 is separated from each of the detection lead wires 16a and 16b, and as a result, the electrical connection between the two detection leads is turned off. Thus, the phase transition of the phase change material 6 can be detected by detecting the conduction state of the phase change material 6. In this case, the phase change material 6 is preferably one having a large surface tension and a small adhesion to the lower layer of the phase change material 6, and it is preferable to use Sn.

Further, the electrical connection between the detection leads can be switched from ON to OFF as follows.
As shown in FIG. 23A, when the phase change material 6 is solid, the phase change material 6 is continuously arranged across the two detection leads, and the electrical connection between the detection leads is turned on. Yes. When the solid phase change material 6 reaches a known phase transition temperature and is liquefied by the heating of the cold junction temperature measuring unit 5, it flows by liquefaction as shown in FIG. The phase change material 6 aggregates and the phase change material 6 is separated, and the electrical connection between the detection leads is turned off. Therefore, the temperature when the electrical connection between the detection leads is turned off becomes a known phase transition temperature. The phase change material 6 is preferably made of a material having a low surface tension and high wettability with the detection lead and the electrical insulating layer 3 under the phase change material 6, and In is suitable.

  In the above, the case where the phase transition of the phase change material is detected by turning off the electrical connection between the detection leads 16a and 16b due to the phase change of the phase change material 6 has been described. The electrical connection between the detection leads 16a and 16b can be switched from OFF to ON by the phase change of the phase change material 6.

FIG. 24 is a diagram illustrating a configuration in which the electrical connection between the detection leads 16a and 16b is switched from OFF to ON.
As shown in FIG. 24 (a), when the phase change material 6 is solid, the phase change material on the electrical insulating layer 3 is separated into two, and the phase change material 6 includes two detection leads 16a and 16b. Intermittently in between. As a result, the electrical connection between the detection leads 16a and 16b is turned off. When the solid phase change material 6 reaches a known phase transition temperature due to the heating of the cold junction temperature measuring unit 5, the solid phase change material 6 flows by liquefaction as shown in FIG. Thus, the phase change material 6 continues across the two detection leads 16a and 16b. Thereby, the electrical connection between the detection leads 16a and 16b is switched from OFF to ON, and the phase transition of the phase change material 6 can be detected. In this case as well, as in the configuration of FIG. 23, the phase change material 6 is preferably made of a material having a small surface tension and a high wettability with the detection lead and the electrical insulating layer 3 under the phase change material 6. Is suitable. When the phase change material 6 cools and solidifies, the phase change material 6 contracts, so that the phase change material 6 on the electrical insulating layer 3 is separated into two again. In the configurations of FIGS. 22 and 23, after the phase change once from solid to liquid, even if the phase change material 6 changes from liquid to solid again, the state returns to the initial state, The electrical connection between the detection leads 16a and 16b will not be turned on. However, in the configuration shown in FIG. 24, when the phase change material 6 undergoes a phase change from a liquid to a solid, the initial state is restored. Temperature calibration can be performed.

  In addition, when a phase change is detected by electrically detecting a change in fluidity (viscosity) due to a phase transition of the phase change material 6 from a solid to a liquid, the phase change material 6 is covered with an electrical insulating layer. As a result, the fluidity of the phase change material 6 may be hindered and the fluid may not be deformed. Therefore, when the configurations of FIGS. 22 to 24 are employed, the phase change material 6 is exposed without covering the electrical insulating layer. Further, it is preferable to reduce the amount of the phase change material 6 so that the phase change material 6 is quickly heated to the phase transition temperature.

[Modification 5]
25 is a schematic plan view of the substrate provided with the cold junction C of the temperature measuring device 100E of the fifth modified example, FIG. 26 is a sectional view taken along the line DD of FIG. 25, and FIG. It is a control block diagram of the temperature measuring device of FIG.
The temperature measuring device 100E of the modified example 5 includes a piezoelectric film 17 provided under the phase change materials 6A and 6B, and the piezoelectric film 17 changes the volume change, the rigidity change, and the inherent change caused by the phase change of the phase change materials 6A and 6B. A change in frequency or the like is detected to detect a phase change in the phase change materials 6A and 6B.

  A piezoelectric film 17 is formed between a pair of piezoelectric drive electrodes 18 provided adjacent to the cold junction temperature measurement unit 5, and phase change materials 6 </ b> A and 6 </ b> B are laminated via the electrical insulating layer 3. As shown in FIG. 27, the signal processing circuit unit 20 is the same as FIG. 4 except that a detection unit 211 that detects the voltage and frequency from the piezoelectric film 17 is provided.

  First, a method for detecting the natural frequency change accompanying the phase change of the phase change material 6 with the piezoelectric film 17 will be described. By applying a method of periodically applying force frequency to the sample and measuring its response, that is, mechanical spectroscopy (dynamic viscoelasticity measurement: DMA), the natural frequency change accompanying the phase change of the phase change material 6 Can be detected. Specifically, an AC voltage is applied to the piezoelectric film 17 to vibrate the piezoelectric film 17 at a predetermined frequency. For example, when the phase change material 6 changes its phase and the natural frequency changes, the piezoelectric film 17 is vibrated at a frequency at which the phase change material 6 resonates with the vibration of the piezoelectric film 17. In this way, by vibrating the piezoelectric film 17, the phase change material 6 on the piezoelectric film 17 vibrates, and stress is applied to the piezoelectric film 17 from the phase change material 6, and a predetermined AC wave is generated from the piezoelectric film 17. Is output. When the phase change material 6 undergoes phase transition and the natural frequency changes, the phase change material 6 resonates with the vibration of the piezoelectric film 17 and vibrates greatly. As a result, the force applied to the piezoelectric film 17 from the phase change material 6 increases, and the amplitude of the AC wave output from the piezoelectric film 17 increases. The control circuit 209 monitors the time differential value ΔV of the amplitude (voltage) of the AC wave output from the piezoelectric film 17, and if the time differential value ΔV takes a non-zero value, it indicates that the phase change material 6 has undergone a phase change. Can be detected. In the above, the phase change material 6 resonates with the vibration of the piezoelectric film 17 due to the phase change of the phase change material 6. On the contrary, the phase change material 6 before the phase change causes the vibration of the piezoelectric film 17 to vibrate. The piezoelectric film 17 may be vibrated so as to resonate with each other. Further, as shown in FIG. 26, since the phase change material 6 and the piezoelectric film 17 are provided on the cavity 21 of the substrate 1, the piezoelectric film 17 easily vibrates and can detect the phase transition with high sensitivity. it can.

  Next, detection of volume change and stiffness change of the phase change material 6 using a piezoelectric material will be described. This is to detect a volume change or a rigidity change of the phase change material 6 by using a so-called piezoresistance effect that is a resistance change of the piezoelectric film due to a mechanical stress applied to the piezoelectric film 17 from the phase change material 6. Specifically, a detection current is applied to the piezoelectric film. When the phase change material 6 is heated to change the phase from solid to liquid, the volume of the phase change material 6 covered by the electrical insulating layer 3 increases. Thereby, the stress with respect to the piezoelectric film of the phase change material 6 increases, and the resistance value of the piezoelectric film changes. Therefore, the control circuit 209 can detect a phase change of the phase change material 6 by detecting a voltage change or a resistance value change of the piezoelectric film. On the other hand, when detecting a change in rigidity of the phase change material 6, when the phase change material 6 changes from a solid to a liquid, the rigidity of the phase change material 6 decreases and the stress applied to the piezoelectric film 17 decreases. As a result, since the resistance value of the piezoelectric film changes, the control circuit 209 can detect the phase change of the phase change material by detecting the voltage change or the resistance value change of the piezoelectric film 17.

FIG. 28 is a timing chart of input / output signals of the temperature calibration of the temperature measuring device 100E of the modified example 5, and FIG. 29 is a temperature calibration, Seebeck coefficient calculation, and measurement object of the temperature measuring device 100E of the modified example 5. It is a flowchart of temperature measurement of.
In FIG. 28 and FIG. 29, the phase change is detected by detecting the resistance value change (voltage change) of the piezoelectric film 17 due to the rigidity change accompanying the phase change of the phase change material 6.

  As shown in FIG. 29, when a calibration execution signal is output (S41), the temperature dependence function stored in the memory is erased (S42), and the cold junction temperature measurement unit 5 is heated by the phase change. A heating current is applied to heat the phase change materials 6A and 6B (S44). Further, a detection current is applied to the piezoelectric film 17, and a voltage value is detected by the detection unit 211. Then, as shown in FIG. 28, the temperature at which one phase change material 6A undergoes phase transition at time T2 (a melting point (freezing point): Mpa, which is a known value unique to phase change material 6A). At this time, the phase change material 6A undergoes a phase transition from the solid phase to the liquid phase, whereby the rigidity of the phase change material 6A changes and the stress applied to the piezoelectric film 17 decreases. As a result, it is possible to detect that voltage value Vf has decreased and phase change material 6A has undergone a phase change.

  Therefore, as shown in FIG. 29, when it is detected that the voltage value Vf has changed (YES in S46), the control circuit 209 uses the calculated resistance value as the electrical resistance of the cold junction temperature measurement unit 5 at the phase transition temperature MPa. The value Ra is set (S47). When the heating current is further increased, as shown in FIG. 28, the temperature at which the other phase change material 6B undergoes phase transition at time T4 (melting point (freezing point): Mpb, which is a known value unique to the phase change material 6B). become. At that time, the phase change material 6B undergoes a phase transition from the solid phase to the liquid phase, whereby the rigidity of the phase change material 6B changes and the stress applied to the piezoelectric film 17 further decreases. As a result, it is possible to detect that voltage value Vf further decreases and phase change material 6B has undergone a phase change.

  Therefore, as shown in FIG. 29, when it is detected again that the voltage value Vf has changed (YES in S50), the control circuit 209 uses the calculated resistance value of the cold junction temperature measurement unit 5 at the phase transition temperature MPb. The electric resistance value Rb is set (S51).

  Next, as shown in FIG. 19, the electrical resistance value Ra of the cold junction temperature measurement unit 5 at the phase transition temperature MPa and the electrical resistance value Rb of the cold junction temperature measurement unit 5 at the phase transition temperature MPb. Then, a function of temperature dependence is obtained and stored in the memory. Then, the application of the heating current to the cold junction temperature measurement unit 5 is turned off, and the temperature calibration is completed (S52). The subsequent flow for calculating the Seebeck coefficient and the flow for measuring the temperature of the measurement object are the same as described above, and a description thereof will be omitted.

  What was demonstrated above is an example and this invention has an effect peculiar to every following (1)-(21) aspect.

(1)
Cold junction temperature measurement means such as the cold junction temperature measurement unit 5 that measures the temperature of the cold junction of the thermocouple, the thermocouple, the output value of the thermocouple, the measurement result of the cold junction temperature measurement means, and the Seebeck coefficient In the temperature measuring device for measuring the temperature of the measurement object based on the heating means such as the heating unit 15 for heating the cold junction, and the thermocouple when the cold junction is heated by the heating means and the temperature of the cold junction is the first temperature And the output value of the thermocouple at the second temperature different from the first temperature, the output value of the thermocouple at the first temperature, the first temperature, the second temperature and the second temperature Seebeck coefficient calculation means such as a Seebeck coefficient S calculation circuit 206 for calculating the Seebeck coefficient based on the output value of the thermocouple was provided.
By providing such a configuration, as described above, even when the thermocouple deteriorates with time and the Seebeck coefficient S changes, it is possible to perform highly accurate temperature measurement. As a result, accurate temperature measurement can be performed over time. In addition, thermocouples having different Seebeck coefficients can be used, and the convenience of the apparatus can be improved.

(2)
In the temperature measuring device according to the aspect described in (1) above, the Seebeck coefficient calculating means includes an output value of a thermocouple when the temperature of the cold junction is the first temperature, and a value when the temperature of the cold junction is the second temperature. Measure the output value of the thermocouple multiple times and calculate the Seebeck coefficient when the error of the output value of the thermocouple at the first temperature and the error of the output value of the thermocouple at the second temperature are below the threshold To do.
By providing such a configuration, it is verified that the temperature of the hot junction is constant, and the Seebeck coefficient is calculated. Therefore, the Seebeck coefficient with high accuracy can be calculated.

(3)
In the temperature measuring device according to the aspect described in (1) or (2) above, the cold junction temperature measuring means is constituted by a temperature-dependent resistor, and the cold junction temperature measuring means is used as the heating means.
By providing such a configuration, the cost can be reduced compared to the case where the heating means and the cold junction temperature measurement means are provided separately. Further, the heat capacity of the substrate can be reduced, and the cold junction can be quickly heated to the first temperature and the second temperature.

(4)
In the temperature measuring device according to any one of the above aspects (1) to (3), the substrate provided with the cold junction is provided with an insulating layer laminated on the base material, and the insulating layer is provided with the base material and A non-contact area that is not in contact was provided, and the cold junction, the heating means, and the cold junction temperature measurement means were provided in the non-contact area.
By providing such a configuration, the heat capacity of the region (measurement region) where the cold junction, the heating unit, and the cold junction temperature measurement unit of the substrate are arranged can be reduced. Thereby, the cold junction can be quickly heated to the first temperature and the second temperature.

(5)
In the temperature measuring device according to the aspect described in (4) above, a through hole is provided in the vicinity of the non-contact region of the insulating layer.
By providing such a configuration, it is possible to suppress the heat of the heating means provided in the non-contact region from propagating to locations other than the non-contact region of the substrate, and to efficiently heat the cold junction. Therefore, the cold junction can be quickly heated to the first temperature and the second temperature.

(6)
In the temperature measuring device according to any of the above aspects (1) to (5), a phase change material having a known phase transition temperature and a phase transition of the phase change material accompanying a change in temperature Phase transition detection means for detecting, and the cold junction temperature measurement means that uses the detection result of the cold junction temperature measurement means when the phase transition detection means detects that a phase transition has occurred as the known phase transition temperature. And a temperature calibration means such as a control circuit 209 for performing temperature calibration.
By providing such a configuration, in the manufacturing process of the temperature measuring device, it is not necessary to provide a temperature calibration step for carrying out the temperature calibration of the cold junction temperature measuring means by transporting the temperature measuring device into the constant temperature environment tank, and the cost can be suppressed. . In addition, since the temperature measuring device itself can perform temperature calibration of the cold junction temperature measuring means, the temperature measuring device is removed from the device to which the temperature measuring device is attached, and the temperature measuring device is brought into the thermostatic environment tank and cooled. Compared with the case where the temperature calibration of the contact temperature measuring means is performed, the temperature calibration of the cold junction temperature measuring means can be easily performed at any time. Thereby, when the temperature calibration of the cold junction temperature measuring means is necessary, the temperature calibration of the cold junction temperature measuring means can be performed, so that high accuracy can be maintained. Thus, since the temperature of a cold junction can be measured with high precision, the temperature measurement of a hot junction (measurement object) can be performed with high precision.

(7)
In the temperature measurement device according to the aspect described in (6) above, the cold junction, the phase change material, the heating means, and the cold junction temperature measurement means are provided on the same substrate.
By providing such a configuration, the phase change material and the temperature of the cold junction temperature measuring means can be made substantially the same, and the temperature calibration of the cold junction temperature measuring means can be performed with high accuracy. Further, the temperature of the cold junction temperature measuring means can be made substantially the same as the temperature of the cold junction, and the cold junction temperature can be measured with high accuracy by the cold junction temperature measuring hand. Further, the cold junction and the phase change material can be favorably heated by the heating means.

(8)
In the temperature measurement device according to the aspect described in (6) or (7), the phase transition detection unit, the temperature calibration unit, and the Seebeck coefficient calculation unit are provided on a substrate provided with the cold junction.
With this configuration, the wiring length of the phase transition detection unit, the temperature calibration unit, and the Seebeck coefficient calculation unit can be shortened, and the phase transition of the phase change substance and the like can be detected with high accuracy without being susceptible to noise. be able to.

(9)
In the temperature measuring device according to any of the above aspects (6) to (8), the phase transition detection unit detects that a phase transition has occurred based on a temperature change measured by the cold junction temperature measuring unit. To do. When the phase change material undergoes a phase change, an endothermic effect occurs or the heat capacity decreases, so when the phase changes, the temperature change differs from that before the phase change. Therefore, by monitoring the temperature change with the cold junction temperature measuring means, the phase transition of the phase change material can be detected with high accuracy.

(10)
In the temperature measuring device according to any one of (6) to (8), the phase transition detection unit includes a piezoelectric body such as a piezoelectric film in which the phase change material is laminated, Any change in volume, stiffness and natural frequency is detected to detect that a phase transition has occurred. When the phase change material undergoes phase transition and the volume and rigidity change, the stress applied to the laminated piezoelectric material in the phase change material changes. As a result, the resistance of the piezoelectric body changes. Therefore, by detecting the resistance change of the piezoelectric body, the piezoelectric body can detect a change in volume and rigidity accompanying the phase change of the phase change material, and accurately detect the phase transition of the phase change material. Can do. Further, by vibrating the piezoelectric body to vibrate the phase change material, the phase change material undergoes phase transition, the natural frequency changes, and the amplitude of the piezoelectric body changes. Therefore, by detecting the amplitude change of the piezoelectric body, the piezoelectric body can detect the change of the natural frequency accompanying the phase transition of the phase change material, and accurately detect the phase transition of the phase change material. Can do.

(11)
In the temperature measuring device according to any of the above aspects (6) to (8), the phase change material is conductive, and the phase transition detection means is based on a change in electrical characteristics of the phase change material. Detecting that a phase transition has occurred. Depending on the phase change material, electrical characteristics such as resistance and capacitance change with the phase change. Therefore, it is possible to detect the phase transition of the phase change material with high accuracy by detecting electrical characteristics such as a resistance value and an electric capacity associated with the phase change of the phase change material.

(12)
In the temperature measuring device according to any of the above aspects (6) to (11), the phase change substance is a substance defined in International Temperature Scale ITS-90. Thereby, temperature calibration of the cold junction temperature measuring means with high accuracy can be performed.

(13)
In the temperature measuring device according to any of the above aspects (6) to (12), at least the phase change material and the heating unit are laminated on a substrate provided with the cold junction. Thereby, the heat transfer efficiency between the phase change material and the heating means is improved, and the phase change material can be rapidly heated to the phase change temperature. Thereby, the temperature calibration of the cold junction temperature measuring means can be performed quickly.

(14)
In the temperature measuring device according to any of the above aspects (6) to (12), at least the phase change material and the heating unit are arranged in parallel on the substrate provided with the cold junction. When laminating the phase change material and the heating means on the substrate provided with the cold junction, after forming the heating means on the substrate, an insulating layer is laminated on the heating means, and the phase change material is formed thereon. It is necessary to provide. On the other hand, by arranging the phase change material and the heating means in parallel on the substrate provided with the cold junction, the heating means and the phase change material can be formed on the substrate. Compared with the case where the heating means is laminated on the substrate provided with the cold junction, the number of manufacturing steps can be reduced, and as a result, the manufacturing cost can be reduced.

(15)
In the temperature measuring device according to any one of the above aspects (6) to (14), the phase change material and the heating unit are provided on the substrate provided with the cold junction, and the phase change material is provided. Were dispersedly arranged at locations adjacent to the heating means. Thereby, the heat capacity of each phase change material can be reduced, and the phase change material can be rapidly heated to the phase transition temperature.

(16)
In the temperature measuring device according to any one of the above (6) to (15), at least the phase change material, the heating unit, and the cold junction temperature measuring unit are arranged and arranged between a pair of cold junctions. It provided in the board | substrate with which the said cold junction was provided so that it might become symmetrical. Thereby, a pair of cold junction can be heated uniformly with a heating means, and the Seebeck coefficient can be calculated with high accuracy. Moreover, since the heat capacities around the cold junctions are substantially the same, the temperature of the measurement object can be measured with high accuracy.

(17)
In the temperature measuring device according to any one of the above (6) to (16), any one of the phase change material, the heating unit, and the cold junction temperature measuring unit is formed of a conductive member, The member comprised by the member was electrically insulated between other members with the electrical insulating material. Thereby, noise due to an electrical short circuit can be suppressed, and the temperature of the cold junction can be measured with high accuracy by the cold junction temperature measuring means.

(18)
In the temperature measuring device according to any of the above aspects (6) to (17), the heating temperature of the heating means when causing the phase change material to undergo phase transition is set in the vicinity of the phase transition temperature of the phase change material. Thereby, useless power consumption at the time of temperature calibration can be suppressed.

(19)
In the temperature measuring device according to any one of the above (6) to (18), two or more kinds of different phase change substances are dispersedly arranged on the substrate provided with the cold junction, and the phase transition detection means includes: Detecting the phase transition of each phase change substance, and the temperature calibration means detects the detection result of the cold junction temperature measurement means when each phase change substance detected by the phase transition detection means undergoes phase transition. The temperature of the cold junction temperature measuring means is calibrated as a known phase transition temperature of the change substance.
By providing such a configuration, a function of temperature dependency of the cold junction temperature measuring means is obtained, and therefore, a resistor material having an unknown resistance temperature coefficient (TCR) can be used as the cold junction temperature measuring means.

(20)
In the temperature measuring device according to any one of (6) to (19) above, a surface protective film is formed that covers at least the periphery of the phase change material with an insulating material. Thereby, the chemical change etc. of a phase change substance can be suppressed and it can suppress that a phase transition temperature changes. In addition, fluctuations in the phase change temperature associated with pressure changes can be prevented. Thereby, stable temperature calibration can be performed over a long period of time.

(21)
In the thermocouple temperature measurement method, the step of measuring the output value ΔV1 of the thermocouple when the temperature of the cold junction is the first temperature t1a and the thermocouple when the second temperature t1b is different from the first temperature t1a. When the stop output value ΔV2 is measured, the Seebeck coefficient is S, and the temperature of the hot junction is t2, the first expression of ΔV1 = S × (t1a−t2) and ΔV2 = S × (t1b− a step of obtaining the Seebeck coefficient S and the temperature t2 of the hot junction from simultaneous solutions with the second equation consisting of t2). Thereby, the temperature of the hot junction can be measured without knowing the Seebeck coefficient of the thermocouple.

1: Substrate 2: Base material 3: Electrical insulating layer 5: Cold junction temperature measurement unit 6: Phase change material 7: Circuit connection electrode 9: Through hole 10: First connection electrode 11: Second connection electrode 15: Heating unit 16 : Detection lead wire 17: piezoelectric film 20: signal processing circuit unit 21: cavity portion 22: measurement region 30: measurement object 100: temperature measuring device 101: sheath portion 102: metal protective tube 103: thermocouple 103 a: first thermoelectric Material 103b: Second thermoelectric material 104: Inorganic substance 110: Temperature measuring unit 111: Case 111a: Connection port 112: Pressure plate spring 114: Slide knob 201: Power source 202: Resistance value detection unit 203: Register 204: Thermoelectromotive voltage Detection unit 206: Seebeck coefficient calculation circuit 207: temperature conversion unit 209: control circuit C: cold junction S: Seebeck coefficient t1a: first temperature t1b: second temperature t2: hot junction temperature W: Contact

JP 2002-156279 A Japanese Patent No. 3692908

Claims (21)

A thermocouple,
Cold junction temperature measuring means for measuring the temperature of the cold junction of the thermocouple;
In the temperature measurement device that measures the temperature of the measurement object based on the output value of the thermocouple, the measurement result of the cold junction temperature measurement means, and the Seebeck coefficient,
Heating means for heating the cold junction;
The cold junction is heated by the heating means, and the output value of the thermocouple when the temperature of the cold junction is the first temperature and the output value of the thermocouple when the second temperature is different from the first temperature are detected. And
Seebeck coefficient calculating means for calculating the Seebeck coefficient based on the first temperature, the output value of the thermocouple at the first temperature, the second temperature, and the output value of the thermocouple at the second temperature. A temperature measuring device characterized by comprising. The temperature measuring device according to claim 1,
The Seebeck coefficient calculating means includes a plurality of output values of the thermocouple when the temperature of the cold junction is the first temperature and output values of the thermocouple when the temperature of the cold junction is the second temperature. And measuring the Seebeck coefficient when an error in the output value of the thermocouple at the first temperature and an error in the output value of the thermocouple at the second temperature are equal to or less than a threshold value. A characteristic temperature measuring device. The temperature measuring device according to claim 1 or 2,
The cold junction temperature measuring means is composed of a resistor having temperature dependence,
A temperature measuring apparatus using the cold junction temperature measuring means as the heating means. In the temperature measuring device in any one of Claims 1 thru | or 3,
The substrate provided with the cold junction is provided with an insulating layer laminated on a base material,
A temperature measurement characterized in that a non-contact area not in contact with the base material is provided in the insulating layer, and the cold junction, the heating means, and the cold junction temperature measurement means are provided in the non-contact area. apparatus. The temperature measuring device according to claim 4, wherein
A temperature measuring device, wherein a through hole is provided in the vicinity of the non-contact region of the insulating layer. The temperature measuring device according to any one of claims 1 to 5,
A phase change material having a known phase transition temperature; and
A phase transition detection means for detecting that the phase transition of the phase change material has occurred with a change in temperature;
Temperature calibration means for performing temperature calibration of the cold junction temperature measuring means with the detection result of the cold junction temperature measuring means when the phase transition detecting means detects that a phase transition has occurred as the known phase transition temperature. And a temperature measuring device. The temperature measuring device according to claim 6, wherein
A temperature measuring apparatus, wherein the cold junction, the phase change material, the heating means, and the cold junction temperature measuring means are provided on the same substrate. The temperature measuring device according to claim 6 or 7,
A temperature measuring device, wherein the phase transition detection means, the temperature calibration means, and the Seebeck coefficient calculation means are provided on a substrate provided with the cold junction. The temperature measuring device according to any one of claims 6 to 8,
The temperature measurement apparatus characterized in that the phase transition detection means detects that a phase transition has occurred based on a temperature change measured by the cold junction temperature measurement means. The temperature measuring device according to any one of claims 6 to 8,
The phase transition detection means includes a piezoelectric body laminated on the phase change material, and detects any change in volume, rigidity, or natural frequency of the phase change material with the piezoelectric body, and the phase transition is detected. A temperature measuring device characterized by detecting what has happened. The temperature measuring device according to any one of claims 6 to 8,
The phase change material is conductive,
The temperature measurement apparatus, wherein the phase transition detection means detects that a phase transition has occurred based on a change in electrical characteristics of the phase change material. The temperature measuring device according to any one of claims 6 to 11,
The temperature measuring device, wherein the phase change material is a material defined in International Temperature Scale ITS-90. The temperature measuring device according to any one of claims 6 to 12,
At least the phase change material and the heating means are laminated on a substrate provided with the cold junction. The temperature measuring device according to any one of claims 6 to 12,
At least the phase change material and the heating means are arranged in parallel on a substrate provided with the cold junction. The temperature measuring device according to any one of claims 6 to 14,
The substrate provided with the cold junction is provided with the phase change material and the heating means,
A temperature measuring apparatus, wherein the phase change substance is dispersedly arranged at a location adjacent to the heating means. The temperature measuring device according to any one of claims 6 to 15,
At least the phase change material, the heating means, and the cold junction temperature measurement means are provided on a substrate provided with the cold junction so that the shape and arrangement are symmetrical between a pair of cold junctions. Cooling point temperature measuring device. The temperature measuring device according to any one of claims 6 to 16,
Any one of the phase change material, the heating unit, and the cold junction temperature measurement unit is formed of a conductive member, and the member formed of the conductive member is electrically insulated from other members by an electrical insulating material. A temperature measuring device characterized by that. The temperature measuring device according to any one of claims 6 to 17,
A temperature measuring apparatus characterized in that the heating temperature of the heating means when causing the phase change substance to undergo phase transition is set in the vicinity of the phase transition temperature of the phase change substance. The temperature measuring device according to any one of claims 6 to 18,
Two or more types of phase change materials different from each other are dispersedly disposed on the substrate provided with the cold junction, and the phase transition detection means detects the phase transition of each phase change material,
The temperature calibration means uses the detection result of the cold junction temperature measurement means when each phase change material detected by the phase transition detection means has undergone a phase transition as a known phase transition temperature of each phase change substance as the cold junction temperature. A temperature measuring apparatus for performing temperature calibration of a measuring means. The temperature measuring device according to any one of claims 6 to 19,
A temperature measuring apparatus comprising a surface protective film that covers at least the periphery of the phase change material with an insulating material. In the thermocouple Seebeck coefficient calculation method,
Measuring the thermocouple output value ΔV1 when the temperature of the cold junction of the thermocouple is a first temperature t1a;
A step of measuring the output value ΔV2 of the thermocouple when different second temperatures t1b to the above first temperature t1a,
Assuming that the Seebeck coefficient is S and the temperature of the hot junction is t2, simultaneous solutions of the first equation consisting of ΔV1 = S × (t2−t1a) and the second equation consisting of ΔV2 = S × (t2−t1b) A step of obtaining the Seebeck coefficient S from the above.

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