Element array circuit, control method thereof, and electromagnetic wave sensor equipped with the element array circuit.

Abstract

This design enables electromagnetic wave measurement across a wide range of ambient temperature environments while minimizing the complexity of the output signal readout and processing circuits. [Solution] The element array circuit comprises a row A, a column wire B, a thermistor element SC connected thereto, power supplies VT1 and VT2 connected to row A, and control units CTRL1 and CTRL2 connected to row A and column wire B. The control units CTRL1 and CTRL2 maintain the thermistor element SC at a temperature within a predetermined range, acquire the base voltage value Vbase(j) output through column wire B, acquire the measured voltage value Vmeas1(i,j) output through column wire B, and calculate the net voltage value Vcorr(i,j), which is the difference between the measured voltage value Vmeas1(i,j) and the base voltage value Vbase(j).

Description

Technical Field

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[0001] The present invention relates to an element array circuit, particularly an element array circuit in which a plurality of thermistor elements are arranged in an array, a control method thereof, and an electromagnetic wave sensor including the element array circuit.

Background Art

[0002] Conventionally, a technique of using a resistance element array circuit having a plurality of resistance elements arranged in a matrix as, for example, an infrared detection circuit is known (see, for example, Patent Document 1). In this infrared detection circuit, a plurality of infrared-sensitive resistors such as thermistor elements whose resistance values change according to temperature changes are arranged.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, generally, the resistance value of a thermistor element can vary greatly depending on the ambient temperature. As a result, in a conventional element array circuit, in order to read an output signal corresponding to a wide resistance value range of the thermistor element, the circuit for reading and processing the output signal tends to become complicated. In particular, when amplifying and outputting a signal from a thermistor element with an operational amplifier or the like, there is a concern that the gain of the input / output voltage fluctuates greatly due to the influence of the ambient temperature, and thus the circuit configuration and arithmetic processing for correcting it become extremely complicated.

[0005] Therefore, an object of the present disclosure is to provide an element array circuit capable of measuring electromagnetic waves in a wide range of ambient temperature environments, a control method thereof, and an electromagnetic wave sensor including the element array circuit, while suppressing the complication of the circuit for reading and processing the output signal. [Means for solving the problem]

[0006] One aspect of the element array circuit according to this disclosure comprises a plurality of first wirings (wax wires, feed lines) extending in a first direction, one or more second wirings (column wires, read lines) extending in a second direction, a plurality of first thermistor elements, each connected to one of the first wirings and one of the second wirings, a first power supply configured to supply a first potential, a second power supply configured to supply a second potential different from the first potential, and a control unit.

[0007] The control unit then performs a "temperature control operation," applying a first potential to multiple first wires to allow current to flow through the thermistor element, thereby adjusting the first potential and maintaining the first thermistor element within a predetermined temperature range, while the first thermistor element is not irradiated with electromagnetic waves from the object being measured. Furthermore, as a "base voltage value acquisition operation," while the first thermistor element is irradiated with electromagnetic waves from the object being measured, the adjusted first voltage is applied to multiple first wires, and the base output value output through the second wire is acquired. Finally, as a "measurement operation," while the first thermistor element is irradiated with electromagnetic waves from the object being measured, the second potential is applied to one first wire selected from the multiple first wires, and the adjusted first potential is applied to the first wires other than the selected one, and the measurement output value output through the second wire is acquired. Then, as a "measurement output value correction operation," the difference between the measurement output value and the base output value is calculated.

[0008] Furthermore, one embodiment of the element array circuit according to this disclosure may include one first wiring extending in a first direction, one or more second wirings extending in a second direction, one or more first thermistor elements, each of which is connected to one of the first wirings and one of the second wirings, a first power supply configured to supply a first potential, a second power supply configured to supply a second potential different from the first potential, and a control unit.

[0009] The control unit then performs a "temperature control operation," applying a first potential to one of the first wires to allow current to flow through the first thermistor element, thereby adjusting the first potential and maintaining the first thermistor element within a predetermined temperature range, while the first thermistor element is not irradiated with electromagnetic waves from the object being measured. Furthermore, as a "base output value acquisition operation," while the first thermistor element is irradiated with electromagnetic waves from the object being measured, the adjusted first potential is applied to one of the first wires, and the base output value output through the second wire is acquired. Finally, as a "measurement operation," while the first thermistor element is irradiated with electromagnetic waves from the object being measured, a second potential is applied to one of the first wires, and the measurement output value output from the second wire is acquired. Then, as a "measurement output value correction operation," the difference between the measurement output value and the base output value is calculated.

[0010] Alternatively, one embodiment of the element array circuit according to the present disclosure may include a plurality of first wirings extending in a first direction, one or more second wirings extending in a second direction, a third wiring extending in a second direction, a plurality of first thermistor elements, each connected to one of the first wirings and one of the second wirings, a plurality of second thermistor elements, each connected to one of the first wirings and the third wiring and shielded from electromagnetic waves from the object to be measured, a first power supply configured to supply a first potential, a second power supply configured to supply a second potential different from the first potential, and a control unit.

[0011] The control unit then performs a "temperature control operation," applying a first potential to multiple first wires while the first thermistor element is not irradiated with electromagnetic waves from the object being measured, thereby flowing current through the first and second thermistor elements and adjusting the first potential to maintain the first and second thermistor elements within a predetermined temperature range. Furthermore, as a "base output value acquisition operation," while the first thermistor element is irradiated with electromagnetic waves from the object being measured, the adjusted first potential is applied to multiple first wires, and a differential base output value is acquired, which is the difference between the first base output value output through the second wire and the second base output value output through the third wire. Furthermore, as a "measurement operation," with the first thermistor element irradiated with electromagnetic waves from the object to be measured, a second potential is applied to one first wire selected from multiple first wires, and the adjusted first voltage is applied to the first wires other than the selected one. A differential measurement output value is then obtained, which is the difference between the first measurement output value output through the second wire and the second measurement output value output through the third wire. Then, as a "measurement output value correction operation," the difference between the differential measurement output value and the differential base output value is taken.

[0012] Furthermore, one embodiment of the element array circuit according to this disclosure may include a first wiring extending in a first direction, one or more second wirings extending in a second direction, a third wiring extending in a second direction, one or more first thermistor elements each connected to one of the first wirings and one of the second wirings, a second thermistor element connected to one of the first wirings and the third wirings and shielded from electromagnetic waves from the object to be measured, a first power supply configured to supply a first potential, a second power supply configured to supply a second potential different from the first potential, and a control unit.

[0013] The control unit then performs a "temperature control operation" by applying a first potential to one first wire while the first thermistor element is not irradiated with electromagnetic waves from the object being measured, thereby flowing current through the first and second thermistor elements and adjusting the first potential to maintain the first and second thermistor elements within a predetermined temperature range. Furthermore, as a "base output value acquisition operation," while the first thermistor element is irradiated with electromagnetic waves from the object being measured, the adjusted first potential is applied to one first wire, and a differential base output value is acquired due to the difference between the first base output value output through the second wire and the second base output value output through the third wire.In addition, as a "measurement operation," while the first thermistor element is irradiated with electromagnetic waves from the object being measured, a second potential is applied to one first wire, and a differential measurement output value is acquired due to the difference between the first measurement output value output through the second wire and the second measurement output value output through the third wire. Then, as part of the "Measurement Output Value Correction Operation," the difference between the differential measurement output value and the differential base output value is taken.

[0014] With the above configuration, the temperature of the thermistor element used to measure electromagnetic waves from the object to be measured can be easily and accurately maintained within a predetermined temperature range by adjusting the first potential through a temperature control operation performed by the control unit. In this state, the control unit measures the electromagnetic waves from the object to be measured, effectively eliminating the influence of ambient temperature at that time. This allows for measurement of electromagnetic waves from the object to be measured in a wide range of ambient temperature environments while keeping the readout and processing circuits for the output signal simple. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the first embodiment of this disclosure. [Figure 2] This is a schematic cross-sectional view showing the general configuration of an example of an electromagnetic wave sensor equipped with an element array circuit according to the present disclosure. [Figure 3] This flowchart shows an overview of the operation example of the electromagnetic wave sensor according to this disclosure. [Figure 4] It is a flowchart showing a part of an operation example of an element array circuit according to the present disclosure. [Figure 5] It is a flowchart showing a part of an operation example of an element array circuit according to the present disclosure. [Figure 6] It is a flowchart showing a part of an operation example of an element array circuit according to the present disclosure. [Figure 7] It is a flowchart showing a part of an operation example of an element array circuit according to the present disclosure. [Figure 8] It is a circuit diagram schematically showing a configuration example of an element array circuit according to the second embodiment in the present disclosure. [Figure 9] It is a circuit diagram schematically showing a configuration example of an element array circuit according to the third embodiment in the present disclosure. [Figure 10] It is a flowchart showing a part of an operation example of an element array circuit according to the present disclosure. [Figure 11] It is a flowchart showing a part of an operation example of an element array circuit according to the present disclosure. [Figure 12] It is a flowchart showing an overview of another operation example of an electromagnetic wave sensor according to the present disclosure. [Figure 13] It is a flowchart showing a part of an operation example of an element array circuit according to the present disclosure. [Figure 14] It is a flowchart showing a part of an operation example of an element array circuit according to the present disclosure. [Figure 15] It is a flowchart showing a part of an operation example of an element array circuit according to the present disclosure. [Figure 16] It is a circuit diagram schematically showing a configuration example of an element array circuit according to the fifth embodiment in the present disclosure. [Figure 17] It is a circuit diagram schematically showing a configuration example of an element array circuit according to the sixth embodiment in the present disclosure. [Figure 18] It is a circuit diagram schematically showing a configuration example of an element array circuit according to the seventh embodiment in the present disclosure. [Figure 19] It is a circuit diagram schematically showing a configuration example of an element array circuit according to the eighth embodiment in the present disclosure. [Figure 20] This is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the ninth embodiment of this disclosure. [Modes for carrying out the invention]

[0016] This embodiment will be described below with reference to the attached drawings. To facilitate understanding of the explanation, the same reference numerals are used for identical components in each drawing whenever possible, and redundant explanations are omitted.

[0017] [First Embodiment] Figure 1 is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the first embodiment of this disclosure. The element array circuit 1 is mounted, for example, on a (far) infrared thermograph and is configured to output an output voltage corresponding to the intensity of electromagnetic waves such as infrared rays irradiated onto the element array circuit 1.

[0018] As shown in Figure 1, the element array circuit 1 comprises a plurality of wax wires Ai (i = integers from 1 to m; the same applies hereafter), a plurality of column wires Bj (j = integers from 1 to n; the same applies hereafter), a plurality of thermistor elements SC(i,j), a plurality of operational amplifiers OP(j), a plurality of resistors R1(j), a wax wire selection unit SA having a plurality of switches SW1(m) and a plurality of switches SW2(m), an ammeter AT, power supplies VT1 and VT2, a first control unit CTRL1, and a second control unit CTRL2. The subscript of the thermistor element SC(i,j) indicates a thermistor element connected to both the i-th wax wire Ai among the m wax wires A1 to Am and the j-th column wire Bj among the n column wires B1 to Bn. Furthermore, the plurality of wax wires Ai and the plurality of column wires Bj are not in direct contact.

[0019] (Waxed wire A) The wax wire Ai corresponds to an example of the "first wiring" in this disclosure and functions as a power supply line to each thermistor element SC(i,j). Each wax wire Ai extends in a first direction (the x-axis direction in the figure) and multiple wax wires Ai are arranged in parallel at predetermined intervals in a second direction (the y-axis direction in the figure). The second direction is different from the first direction. In addition, one end of multiple thermistor elements SC(i,j) is connected to each wax wire Ai. In the example in Figure 1, n thermistor elements SC(i,j) are connected in parallel to each wax wire Ai. More specifically, one end (upper end in the figure) of the thermistor elements SC(1,1) to SC(1,n) arranged in the x-axis direction is connected to the wax wire A1 extending in the x-axis direction. Similarly, one end of each thermistor element SC(2,1) to SC(2,n), which are aligned in the x-axis direction, is connected to the wax wire A2 extending in the x-axis direction, and one end of each thermistor element SC(m,1) to SC(m,n), which are aligned in the x-axis direction, is connected to the wax wire Am extending in the x-axis direction. In the example in Figure 1, one end of each wax wire Ai (right end in the figure) is connected to one end of thermistor element SC(i,n). The other end of each wax wire Ai (left end in the figure) is connected to the ammeter AT, which will be described later.

[0020] (Column line B) The column wire Bj corresponds to an example of the "second wiring" in this disclosure and functions as a readout line for the current corresponding to the resistance value of each thermistor element SC(i,j). Each column wire Bj extends in the second direction (y-axis direction in the figure) and multiple Bj are arranged in parallel at predetermined intervals in the first direction (x-axis direction in the figure). In addition, the other end of multiple thermistor elements SC(i,j) is connected to each column wire Bj. In the example in Figure 1, m thermistor elements SC(i,j) are connected in parallel to each column wire Bj. More specifically, the other end (lower end in the figure) of the thermistor elements SC(1,1) to SC(m,1) arranged in the y-axis direction is connected to the column wire B1 extending in the y-axis direction. Similarly, the other ends of the thermistor elements SC(1,2) to SC(m,2), which are aligned in the y-axis direction, are connected to the column wire B2 extending in the y-axis direction, and the other ends of the thermistor elements SC(1,n) to SC(m,n), which are aligned in the y-axis direction, are connected to the column wire Bn extending in the y-axis direction. In the example in Figure 1, one end of each column wire Bj (upper end in the figure) is connected to the other end of the thermistor element SC(m,j). In addition, the other end of each column wire Bj (lower end in the figure) is connected to the negative input terminal of the operational amplifier OP(j), which will be described later.

[0021] (Thermistor element SC) Thermistor element SC(i,j) corresponds to an example of the "first thermistor element" in this disclosure. As described above, each thermistor element SC(i,j) is connected to both the wax wire Ai and the column wire Bj. That is, in the example in Figure 1, n thermistor elements SC(i,1) to SC(i,n) are connected in parallel to each wax wire Ai, and m thermistor elements SC(1,j) to SC(m,j) are connected to each column wire Bj. Note that there is only one thermistor element SC(i,j) that is connected to both each wax wire Ai and each column wire Bj. Therefore, by selecting one from multiple wax wires Ai and one from multiple column wires Bj, one thermistor element SC(i,j) can be identified (selected).

[0022] Here, the thermistor element SC(i,j) is a photodetector that converts electromagnetic waves, such as infrared and far-infrared rays focused by a lens, into electrical signals. Specifically, it includes a thermistor film as a resistance-changing layer that exhibits a resistance change due to temperature changes. Examples of this thermistor film include vanadium oxide, amorphous silicon, polycrystalline silicon, a spinel-type crystalline oxide containing manganese, titanium oxide, or yttrium-barium-copper oxide. An electromagnetic wave absorption layer that absorbs electromagnetic waves and generates heat is provided adjacent to the thermistor film. Examples of this electromagnetic wave absorption layer include silicon oxide (SiO2), aluminum oxide (Al2O3), silicon nitride (Si3N4), or aluminum nitride (AlN). With these configurations, the thermistor element SC(i,j) functions so that the temperature of the electromagnetic wave absorption layer and the resistance-changing layer change according to the intensity of the received electromagnetic waves, and as a result, the resistance value of the resistance-changing layer changes.

[0023] (Operational amplifier OP) The operational amplifier OP(j) includes a positive input terminal, a negative input terminal, and an output terminal. Of these, the positive input terminal is connected to a predetermined potential. The "predetermined potential" here is not particularly limited as long as it is a potential different from the first potential V1, the second potential V1+V2, and the third potential V1+V3 described later, and in the following explanation, it will be described as the ground potential (zero). As mentioned above, the other end of the corresponding column line Bj is connected to the negative input terminal of each operational amplifier OP(j). Furthermore, the output terminal of each operational amplifier OP(j) is connected to the control unit CTRL2 described later. Such operational amplifier OP(j) operates so that the positive input terminal and the negative input terminal are at the same potential. In addition, each operational amplifier OP(j), in conjunction with the resistor R1(j) described later, functions as a readout circuit for converting the current flowing through the corresponding column line Bj into a voltage and outputting it.

[0024] (Resistor R1) One end of each resistor R1(j) (the upper end in the figure) is connected to the column line Bj, which is connected to the negative input terminal of each operational amplifier OP(j). The other end of each resistor R1(j) (the lower end in the figure) is connected to the signal line extending from the output terminal of the corresponding operational amplifier OP(j). In the example in Figure 1, resistors R1(j) are connected in parallel to each operational amplifier OP(j) arranged in the x-axis direction. More specifically, resistor R1(1) is provided for operational amplifier OP(1) to which column line B1 is connected, resistor R1(2) is provided for operational amplifier OP(2) to which column line B2 is connected, and resistor R1(n) is provided for operational amplifier OP(n) to which column line Bn is connected.

[0025] (Waxed wire selection section SA) The wax wire selection unit SA has a plurality of switches SW1(i) and a plurality of switches SW2(i). These switches SW1(i) and SW2(i) are capable of switching between a conductive state and a non-conductive state. Each switch SW1(i) is provided at the other end (left end in the figure) of each wax wire Ai and is connected collectively to the power supply VT1 via an ammeter AT. When this switch SW1(i) is closed, a potential V1 is applied to each wax wire Ai from the power supply VT1. This power supply VT1 corresponds to an example of the "first power supply" in this disclosure, and the potential V1 corresponds to an example of the "first potential" in this disclosure. Note that the power supply VT1 is connected to ground potential. The power supply VT1 is configured to supply the potential V1.

[0026] On the other hand, each switch SW2(i) is provided on a branch line from each wax wire Ai and is connected in series with power supply VT1 via power supply VT2. Power supply VT1 and power supply VT2 are connected in series. This power supply VT2 corresponds to an example of "other power supply" in this disclosure. When this switch SW2(i) is closed, potentials V1 + V2 are applied to each wax wire Ai from power supply VT1 and power supply VT2. In other words, each of the multiple switches SW1(1) to SW1(m) is provided between one of the corresponding wax wires A1 to Am and power supply VT1, and switches the conduction / non-conductivity between the two. On the other hand, each of the multiple switches SW2(1) to SW2(m) is provided between one of the corresponding wax wires A1 to Am and power supply VT1 and power supply VT2, which are connected in series, and switches the conduction / non-conductivity between the two. A power supply consisting of power supplies VT1 and VT2 connected in series corresponds to an example of the "second power supply" in this disclosure, and the potential V1+V2 corresponds to an example of the "second potential" in this disclosure. The power supplies VT1 and VT2 connected in series are configured to supply a potential V1+V2 that is different from potential V1.

[0027] (Control Units CTRL1, CTRL2) The control unit CTRL1 is connected to the ammeter AT and the power supply VT1. Furthermore, when electromagnetic waves from the object being measured do not incident on the thermistor elements SC(1,1) to SC(m,n), the control unit CTRL1 applies a potential V1 to the wax wires A1 to Am and flows current through the thermistor elements SC(1,1) to SC(m,n). Using the current value I[A] measured by the ammeter AT, the control unit CTRL1 adjusts the power supply VT1 to perform the "temperature control operation" of the thermistor elements SC(1,1) to SC(m,n), which will be described later.

[0028] Furthermore, the control unit CTRL2 is connected to the control unit CTRL1, the wax wire selection unit SA, and each operational amplifier OP(j). The control unit CTRL2 also performs the "base voltage value acquisition operation" described later, which acquires the correction base voltage value Vbase(j)[V] output from each operational amplifier OP(j) while applying a potential V1 to the wax wires A1 to Am when electromagnetic waves from the object to be measured are incident on the thermistor elements SC(1,1) to SC(m,n). Subsequently, the control unit CTRL2 performs the "measurement operation" described later, which acquires the measurement voltage value Vmeas1(i,j)[V] output from each operational amplifier OP(j) while applying a potential V1+V2 to a specific wax wire Ai and a potential V1 to the other wax wires A when electromagnetic waves from the object to be measured are incident on the thermistor elements SC(1,1) to SC(m,n). Furthermore, the control unit CTRL2 performs the "measurement output value correction operation" described later, which calculates the net voltage value Vcorr(i,j) using the measured voltage value Vmeas1(i,j)[V] and the correction base voltage value Vbase(j)[V]. In addition, the control unit CTRL2 performs the "image data conversion operation" described later, which acquires image data indicating the temperature of the object being measured from the finally obtained net voltage value Vcorr(i,j).

[0029] These control units CTRL1 and CTRL2 correspond to an example of a "control unit" as described herein. The control units CTRL1 and CTRL2 are, for example, microcomputers for carrying out each of the above operations, and are configured such that one or more processors in a CPU or other arithmetic unit execute pre-stored control programs and arithmetic programs to perform predetermined control processing.

[0030] [Example of operation in element array circuit 1] Next, an example of operation in the element array circuit 1 will be described below. Figure 2 is a schematic cross-sectional view showing an example of the configuration of an electromagnetic wave sensor equipped with the element array circuit 1 according to this disclosure. The electromagnetic wave sensor 1 generally comprises an element array circuit 1, a base body 20, a housing wall 21, an optical system 30, and a shutter 40 that blocks electromagnetic waves IR irradiated from the measurement target Tg. More specifically, the sensor section 11, which includes thermistor elements SC(i,j) in the element array circuit 1, and a getter material 22 for degassing the internal space are housed in the internal space S defined by the base body 20 and the housing wall 21. Furthermore, the peripheral circuit section 12, which includes control units CTRL1, CTRL2, etc. in the element array circuit 1, is embedded in the base body 20. In addition, the optical system 30 includes predetermined lenses, etc., and is arranged to be interposed between the sensor section 11 of the element array circuit 1 and the measurement target Tg. Furthermore, the shutter 40 is connected to a drive unit 41, which is configured to be connected to and controlled by the peripheral circuit unit 12.

[0031] Figure 3 is a flowchart outlining an example of the operation of the electromagnetic wave sensor 100 according to this disclosure. Figures 4 to 7 are flowcharts showing parts of the procedure for an example of the operation of the element array circuit 1 according to this disclosure. As shown in Figure 3, after processing has started, in step S10, as an "initialization operation," the control unit CTRL1 turns all switches SW1(i) OFF (open: non-conductive state) and all switches SW2(i) OFF (open: non-conductive state).

[0032] Next, in step S20, the control unit CTRL2 closes the shutter 40, so that electromagnetic waves IR from the measurement target Tg do not irradiate all the thermistor elements SC(1,1)~SC(m,n), and the 'temperature control operation' is performed. As shown in Figure 4, first, in step S21, the control unit CTRL2 turns switches SW1(1)~SW1(m) ON (closed: conduction state) and switches SW2(1)~SW2(m) OFF (open: non-conduction state). As a result, a potential V1[V] is applied from the power supply VT1 to all the wax wires A1~Am, and current flows through the thermistor elements SC(1,1)~SC(m,n) according to the potential difference between the potential of the wax wires A1~Am and the potential of the negative input terminal of each operational amplifier OP(j), causing the thermistor elements SC(1,1)~SC(m,n) to heat up and their temperature to rise.

[0033] Furthermore, in step S22, while the potential V1 is continuously applied to the wax wires A1 to Am, the control unit CTRL2 monitors the total current flowing through the wax wires A1 to Am using the ammeter AT. When an appropriate amount of time has elapsed since step S20 (switches SW1(1) to SW1(m) are turned ON, and switches SW2(1) to SW2(m) are turned OFF), or when the change in the total current becomes constant within a predetermined range, or when a predetermined amount of time has elapsed since the change in the total current became constant within a predetermined range, the current value I[A] of the total current is measured and stored. Next, in step S23, the second control unit CTRL2 calculates the measured combined resistance value Rr of the entire thermistor element SC(1,1) to SC(m,n) from the current value I and the applied potential difference V1, using the relationship expressed by the following formula (1). Measured combined resistance value Rr = V1 / I [Ω] …(1)

[0034] Then, from step S24 onward, the control unit CTRL2 compares the target resistance value Rt [Ω], which has been set and held in advance, with the measured combined resistance value Rr [Ω] calculated in step S23, and appropriately increases or decreases the potential V1 applied from the power supply VT1 based on the difference between the two. That is, in step S24, it is determined whether or not the absolute value of the difference between the two is less than a predetermined allowable range ΔR [Ω] (whether or not the condition expressed by the following formula (2) is met). The predetermined allowable range ΔR is, for example, 10% of the target resistance value Rt. |Measured combined resistance value Rr - Target resistance value Rt| < ΔR …(2)

[0035] Then, if the answer in step S24 is "No," that is, if the measured combined resistance value Rr is not within the range of the target resistance value Rt ± ΔR, the second control unit CTRL2 further determines the relationship between the measured combined resistance value Rr and the target resistance value Rt in step S25 based on the condition expressed by the following formula (3). Measured combined resistance Rr > Target resistance Rt …(3)

[0036] Then, if step S25 is "No," that is, if the measured combined resistance value Rr is too small even considering the allowable range ΔR, in step S26, the control unit CTRL2 appropriately reduces the potential V1 applied from the power supply VT1. On the other hand, if step S25 is "Yes," that is, if the measured combined resistance value Rr is too large even considering the allowable range ΔR, in step S27, the control unit CTRL2 appropriately increases the potential V1 applied from the power supply VT1. Then, the control unit CTRL2 returns the process to step S24 and repeats the determination and processing based on the above equations (2) and (3). Note that the example in Figure 4 describes the case where the temperature coefficient of resistance of the thermistor element SC(i,j) is negative (thermistor element SC(i,j) is an NTC thermistor). However, if the temperature coefficient of resistance is positive (thermistor element SC(i,j) is a PTC thermistor), the control of increasing or decreasing the potential V1 will be the opposite of the above.

[0037] On the other hand, if the answer in step S24 is "No," that is, if the measured combined resistance value Rr is within the range of the target resistance value Rt ± ΔR, the control unit CTRL2 completes the process in step S20 without changing the potential V1 applied from the power supply VT1, and proceeds to step S30. In this way, because the measured combined resistance value Rr is maintained within the range of the predetermined target resistance value Rt ± ΔR, the applied potential is the adjusted potential V1, and therefore the temperature due to the heat generated by the thermistor elements SC(1,1) to SC(m,n) is also suitably maintained within a predetermined range. The width of the predetermined temperature range in which thermistor elements SC(1,1) to SC(m,n) are maintained is, for example, 20°C or less, and the predetermined temperature range in which thermistor elements SC(1,1) to SC(m,n) are maintained is, for example, within ±10°C of a predetermined temperature.

[0038] Next, as shown in Figure 5, in step S30 (step S31), all switches SW1(i) are kept ON (closed: conducting state) and all switches SW2(i) are kept OFF (open: non-conducting state) (same state as in step S20), and while maintaining the state in which the adjusted potential V1 (hereinafter referred to as V1a) from the power supply VT1 is applied to all wax wires A1 to Am, the control unit CTRL2 opens the shutter 40, and all thermistor elements SC(1,1) to SC(m,n) are irradiated with electromagnetic waves IR from the measurement target Tg. As a result, the thermistor elements SC(1,1) to SC(m,n) experience temperature changes in accordance with the intensity of the irradiated electromagnetic wave IR, relative to the temperature controlled in step S20. However, since the amount of temperature change caused by opening the shutter 40 and irradiating the thermistor elements SC(1,1) to SC(m,n) with electromagnetic wave IR from the measurement target Tg is small, the temperature of the thermistor elements SC(1,1) to SC(m,n) is maintained within a predetermined range. In step S30, the control unit CTRL2 performs a "base voltage value acquisition operation" (corresponding to an example of the "base output value acquisition operation" in this disclosure) in this state.

[0039] Furthermore, in step S32, the control unit CTRL2 measures the voltage value Vo(j)[V] output from each operational amplifier OP(j), and the control unit CTRL2 acquires the voltage value Vo(j)[V] as a base voltage value Vbase(j) (corresponding to an example of the "base output value" in this disclosure) for correction to the thermistor elements SC(1,j)~SC(m,j) connected to the corresponding column line Bj. Then, the control unit CTRL2 proceeds to step S40. The base voltage value Vbase(j) (the voltage value Vo(j) output from the operational amplifier OP(j)) is an output value output through the column line Bj.

[0040] Next, in step S40, the same state as in step S30 is maintained, that is, the control unit CTRL2 opens the shutter 40 and maintains the state in which all thermistor elements SC(1,1) to SC(m,n) are irradiated with electromagnetic waves IR from the Tg to be measured. In step S40, in this state, the control unit CTRL2 performs the 'measurement operation' of the Tg to be measured. In step 40 as well, the temperatures of the thermistor elements SC(1,1) to SC(m,n) are maintained within a predetermined range. As shown in Figure 6, here, the control unit CTRL2 first assigns "1" to i as a definition process (i=1), and repeats the processes of steps S41 to S44 until the subscript i=m.

[0041] First, in step S41, the control unit CTRL2 turns SW1 (setting i) OFF (open: non-conductive state) and turns switch SW1 (other than setting i) ON (closed: conductive state). Also, SW2 (setting i) is turned ON (closed: conductive state) and switches SW2 (other than setting i) are turned OFF (open: non-conductive state). As a result, the potentials V1a + V2 are applied to the raw wire Ai of setting i from power supplies VT1 and VT2. Here, the raw wire Ai of setting i corresponds to an example of "one first wiring selected from a plurality of first wirings" according to this disclosure. In addition, the potential V1a is applied to the raw wire A other than setting i from power supply VT1. Then, in step S42, the control unit CTRL2 measures the voltage value Vo(j)[V] output from each operational amplifier OP(j), and the control unit CTRL2 acquires the voltage value Vo(j)[V] as the measured voltage value Vmeas1(i,j) (corresponding to an example of the "measured output value" in this disclosure) corresponding to the thermistor element SC(i,j) connected to the corresponding column line Bj. The measured voltage value Vmeas1(i,j) (the voltage value Vo(j) output from the operational amplifier OP(j)) is the output value output through the column line Bj.

[0042] Next, in step S43, the control unit CTRL2 turns all switches SW1(i) ON (closed: conduction state) and all switches SW2 OFF (closed: non-conduction state). Then, as a definition process, the control unit CTRL2 increments i by 1 (i=i+1), and in step S44, it determines whether i>m. If "No", the process returns to step S41; if "Yes", the process proceeds to step S50.

[0043] More specifically, in steps S41 and S42 above, first, when i=1, switch SW1(1) is turned OFF, switches SW1(2) to SW1(m) are turned ON, switch SW2(1) is turned ON, and switches SW2(2) to SW2(m) are turned OFF. As a result, a potential of V1a+V2 is applied to the wax wire A1, and a potential of V1a is applied to the other wax wires A2 to Am. Then, the measured voltage values ​​Vmeas1(1,1) to Vmeas1(1,n) corresponding to the thermistor elements SC(1,1) to SC(1,n) are obtained.

[0044] Next, when i=2, switch SW1(2) is turned OFF, switches SW1(1), SW1(3) to SW1(m) are turned ON, switch SW2(2) is turned ON, and switches SW2(1), SW2(3) to SW2(m) are turned OFF. As a result, a potential of V1a+V2 is applied to the wax wire A2, and a potential of V1a is applied to the other wax wires A1, A3 to Am. Then, the measured voltage values ​​Vmeas1(2,1) to Vmeas1(2,n) corresponding to the thermistor elements SC(2,1) to SC(2,n) are measured and stored.

[0045] Similarly, when i=m, switch SW1(m) is turned OFF, switches SW1(1) to SW1(m-1) are turned ON, switch SW2(m) is turned ON, and switches SW2(1) to SW2(m-1) are turned OFF. As a result, a potential of V1a+V2 is applied to the wax wire Am, and a potential of V1a is applied to the other wax wires A1 to Am-1. Then, the measured voltage values ​​Vmeas(m,1) to (m,n) corresponding to the thermistor elements SC(m,1) to SC(m,n) are measured and stored.

[0046] Furthermore, in step S50, the control unit CTRL2 primarily performs a "measurement output value correction operation" as a calculation process using the output values ​​acquired so far. As shown in Figure 7, here, first, as a definition process, "1" is substituted for i and j (i=1, j=1), and the processes in steps S51 to S53 are repeated until the subscripts i=m and j=n. In step S51, the control unit CTRL2 takes the difference between the measurement voltage value Vmeas1(i,j) and the base voltage value Vbase(j). More specifically, in step S51, when a potential V1a+V2 is applied to the wax wire Ai of setting i, and a potential V1a is applied to the wax wire A other than setting i, a correction base voltage value Vbase(j) is subtracted from the measured voltage value Vmeas1(i,j) to remove the effect of the potential V1a being applied to the wax wires A1~Am for temperature adjustment. This calculates the net voltage value Vcorr(i,j) that should be output for each thermistor element SC(i,j) when a potential V2 is applied to the wax wire Ai (see equation (4) below). Vcorr(i,j)=Vmeas1(i,j)-Vbase(j) …(4)

[0047] Next, the control unit CTRL2 performs a definition process by incrementing j by 1 (j=j+1), and in step S52, it determines whether j>n. If "No", it returns to S51. If "Yes", it performs a definition process by incrementing i by 1 (i=i+1) and resetting j to 1 (j=1). Then, in step S53, the control unit CTRL2 determines whether i>m. If "No", it returns to S51. If "Yes", it proceeds to step S60. In step S60, the control unit CTRL2 performs, for example, an "image data conversion operation", and finally converts the obtained net voltage value Vcorr(i,j) into image data indicating temperature using an appropriate image conversion processing program, outputs it to the outside as appropriate, and then terminates the process.

[0048] To further facilitate understanding, the validity of the relationship expressed in equation (4) above will be illustrated. For simplicity, the element array circuit 1 will consist of a 3x3 array of thermistor elements SC(i,j) (m=3, n=3). Then, the measured voltage values ​​Vmeas1(i,j) measured in steps S41 and S42 corresponding to thermistor elements SC(1,1), SC(1,2), and SC(1,3) connected to the wax wire A1(i=1) will be expressed as the voltage output from each operational amplifier OP(j), as shown in equations (5) to (7) below, due to the characteristics of the operational amplifiers. Note that RR(i) represents the resistance value of resistor R1(i), and RS(i,J) represents the resistance value of thermistor element SC(i,j) (the same applies below).

[0049]

number

[0050] When these are grouped by potential V1a and V2, they are shown in equations (5') to (7') below.

number

[0051] As shown above, the first term on the right-hand side of equations (5') to (7') (the multiplication term of potential V2) is positively the net voltage values ​​Vcorr(1,1) to Vcorr(1,3) that should be output corresponding to each thermistor element SC(1,1) to SC(1,3) when potential V2 is applied to the wax wire A1. Also, the second to fourth terms on the right-hand side of equation (5') (the linear combination term of the multiplication term of potential V1a) is positively the correction base voltage value Vbase(1) to eliminate the effect when potential V1a is applied to the wax wires A1 to A3 for temperature control. Similarly, the second to fourth terms on the right-hand side of equation (6') are the correction base voltage value Vbase(2), and the second to fourth terms on the right-hand side of equation (7') are the correction base voltage value Vbase(3). Therefore, the relationships exemplified in equations (5') to (7') above can be summarized as equation (4') below. Since equation (4') is equivalent to equation (4) above, the validity of equation (4) can be understood. Vmeas1(i,j)=Vcorr(i,j)+Vbase(j) …(4')

[0052] [Effects of element array circuit 1] As described above, in the element array circuit 1 according to the first embodiment and the electromagnetic wave sensor 100 equipped therewith, prior to imaging the measurement target Tg (detection of electromagnetic wave IR), the control unit CTRL1 adjusts the potential V1 applied to the wax wires A1 to Am (first wiring), thereby maintaining the thermistor elements SC(1,1) to SC(m,n) within a predetermined temperature range (temperature control operation).

[0053] Then, the control unit CTRL2 applies the adjusted potential V1a to the wax wires A1 to Am to which thermistor elements SC(1,1) to SC(m,n) are connected, and with the thermistor elements SC(1,1) to SC(m,n) irradiated with electromagnetic waves IR from the target Tg, it obtains the correction base voltage value Vbase(j) output from the operational amplifier OP(j) (base voltage value acquisition operation). Then, the control unit CTRL2 applies the potential V1a+V2 to the wax wire Ai, and applies the potential V1a to the wax wires A other than the set i, and with the thermistor elements SC(1,1) to SC(m,n) irradiated with electromagnetic waves IR from the target Tg, it obtains the measurement voltage value Vmeas1(i,j) output from the operational amplifier OP(j) (measurement operation).

[0054] Then, the control unit CTRL2 takes the difference between the measured voltage value Vmeas1(i,j) and the base voltage value Vbase(j) (measured output value correction operation). As a result, the control unit CTRL2 calculates the net voltage value Vcorr(i,j) that should be output for each thermistor element SC(i,j) when a potential V2 is applied to the wax wire Ai. The control unit CTRL2 then converts this net voltage value Vcorr(i,j) into image data as appropriate and outputs it, thereby visualizing the two-dimensional intensity distribution of electromagnetic waves IR from the measurement target Tg (for example, the two-dimensional temperature distribution of the measurement target Tg) (image data conversion operation).

[0055] In this way, the temperature of the thermistor element SC(i,j) used to measure the electromagnetic wave IR from the target Tg can be easily and accurately maintained within a predetermined temperature range by adjusting the potential V1 through the temperature control operation performed by the control unit CTRL1. Then, in this state, the control unit CTRL2 measures the electromagnetic wave IR from the target Tg, effectively eliminating the influence of ambient temperature at that time. This allows for measurement of electromagnetic wave IR from the target Tg in a wide range of ambient temperature environments while keeping the readout and processing circuits for the output signal simple.

[0056] [Second Embodiment] Figure 8 is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the second embodiment of this disclosure. The element array circuit 2 is configured in the same way as the element array circuit 1 shown in Figure 1, except that power supply VT1, power supply VT2, ammeter AT, and control unit CTRL1 are provided for each wax wire Aj.

[0057] The element array circuit 2 configured in this way, and the electromagnetic wave sensor 100 equipped therewith, can be operated by a procedure substantially equivalent to that shown in the flowchart in Figure 3. Moreover, the "temperature control operation" performed in step S20 can be performed for each wax wire Ai, rather than for all wax wires A1 to Am at once. With this configuration, even if there are slight variations in the temperature resistance characteristics of the thermistor elements SC(i,j), their temperature control can be performed more precisely, making it possible to measure the electromagnetic wave IR radiated from the target Tg with higher accuracy.

[0058] [Third Embodiment] Figure 9 is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the third embodiment of this disclosure. The element array circuit 3 is configured similarly to the element array circuit 1 shown in Figure 1, except that a portion of the thermistor element SC(i,j) (here, thermistor elements SC(1,1) to SC(1,n) connected to the wax wire A1) are covered with a shielding SLD that blocks electromagnetic waves IR, thereby shielding them from electromagnetic waves IR from the measurement target Tg, and that a power supply VT3 that supplies potential V3 is connected to the wax wire A1 instead of power supply VT2. Power supplies VT1 and VT3 are connected in series. This power supply VT3 corresponds to an example of "further other power supplies" according to this disclosure. Here, the polarity of potential V2 and the polarity of potential V3 are set to be opposite. In other words, the polarity of potential V2, obtained by subtracting potential V1 from potential V1+V2, and the polarity of potential V3, obtained by subtracting potential V1 from potential V1+V3, are set to be opposite. In the third embodiment, wax wire A1 corresponds to an example of a "third wiring extending in the first direction" according to the Disclosure, wax wires A2 to Am correspond to an example of a "first wiring" according to the Disclosure, thermistor elements SC(1,1) to SC(1,n) covered with shield SLD correspond to an example of a "second thermistor element" according to the Disclosure, thermistor elements SC(2,1) to SC(m,n) other than thermistor elements SC(1,1) to SC(1,n) correspond to an example of a "first thermistor element" according to the Disclosure, power supplies VT1 and VT3 connected in series correspond to an example of a "third power supply" according to the Disclosure, and potential V1 + V3 corresponds to an example of a "third potential" according to the Disclosure.

[0059] The electromagnetic wave sensor 100 equipped with the element array circuit 3 configured in this way can also be operated by a procedure substantially equivalent to that of the flowchart shown in Figure 3, except that steps S40' and S50' are performed instead of steps S40 and S50. In this embodiment, the polarity of potential V2, obtained by subtracting potential V1 from potential V1+V2, and the polarity of potential V3, obtained by subtracting potential V1 from potential V1+V3, are set to be opposite, and the polarity of potential V2 and potential V3 are set to be opposite. This makes it possible to minimize the effect of self-heating of the thermistor element SC(i,j) due to the current (sense current) caused by the difference (potential V2) between the potential applied to the wax wire Ai during the measurement operation of the target Tg in step S40' and the potential applied to the wax wire Ai during the base voltage value acquisition operation. Furthermore, the potential V2 supplied from power supply VT2 and the potential V3 supplied from power supply VT3 may be set to have the same absolute value, or they may be set to have slightly different absolute values, taking into account the individual characteristic variations of the thermistor element SC(i,j) and the output range of the operational amplifier OP(j).

[0060] Here, Figures 10 and 11 are flowcharts showing a part of the operation example of the element array circuit 3 according to this disclosure, respectively. Figure 10 shows an overview of step S40', and Figure 11 shows an overview of step S50'. Step S40' is substantially equivalent to the process in step S40, except that, as the initial definition process, i=2 is substituted for i=1, which corresponds to the first thermistor element SC(2,1)~(2,n) that is not covered by the shield SLD, instead of i=1, which corresponds to the thermistor elements SC(1,1)~(1,n) that are covered by the shield SLD, and step S41' is executed instead of step S41.

[0061] In other words, in step S41', the control unit CTRL2 turns SW1 (setting i) OFF (open: non-conductive state), turns the switch SW1(1) corresponding to i=1 OFF (open: non-conductive state), and turns the switches SW1 (other than 1 and setting i) ON (closed: conductive state). Also, SW2 (setting i) is turned ON (closed: conductive state), turns the switch SW2(1) corresponding to i=1 ON (closed: conductive state), and turns the switches SW2 (other than 1 and setting i) OFF (open: non-conductive state). As a result, the potential V1a+V2 is applied to the wax wire Ai of setting i from power supplies VT1 and VT2. In addition, the potential V1+V3 is applied to the wax wire A1 to which the thermistor elements SC(1,1)~(1,n), which are covered with shield SLD, are connected from power supplies VT1 and VT3. Furthermore, a potential V1a is applied from power supply VT1 to all other wax wires A except for setting i, excluding wax wire A1.

[0062] Then, in step S42, the measured voltage value Vmeas1(i,j) corresponding to the thermistor element SC(i,j) connected to each column line Bj is obtained (however, i=2 or greater), step S43 is performed, and the setting in step S44 is the same as the processing in step S40. Furthermore, step S50' following step S40' is essentially the same as the processing in step S50, except that as the initial definition process, i=2 corresponding to the first thermistor element SC(2,1)~(2,n) that is not covered by the shield SLD is substituted instead of i=1 corresponding to the thermistor elements SC(1,1)~(1,n) that are covered by the shield SLD.

[0063] Then, in step S51, the control unit CTRL2 takes the difference between the measured voltage value Vmeas1(i,j) and the base voltage value Vbase(j)(i≧2). More specifically, in this embodiment, in step S51, the base voltage value Vbase(j) used for correction to remove the effect of applying potential V1a to wax wires A1~Am for temperature adjustment is subtracted from the measured voltage value Vmeas1(i,j) when a potential V1a+V2 is applied to wax wire Ai(i≧2) of setting i, a potential V1a+V3 is applied to wax wire A1, and a potential V1a is applied to wax wires A other than wax wire A1 that are not setting i. Then, steps S52, S53 and step S60 described above are performed in order to complete the process.

[0064] Here, as with the first embodiment, the validity of this embodiment will also be illustrated below. Here again, to simplify the explanation, the element array circuit 1 is a thermistor element SC(i,j) array with 3 rows x 3 columns (m=3,n=3). Then, the measured voltage value Vmeas1(i,j) measured in steps S41' and S42 corresponding to the thermistor elements SC(2,1), SC(2,2), and SC(2,3) that are not covered by the shield SLD connected to the wax wire A2(i=2) is expressed as the voltage output of the operational amplifier OP(j), and from the characteristics of the operational amplifier, it is as shown in equations (8) to (10) below.

[0065]

number

[0066] When these are grouped by potential V1, V2, and V3, they are shown in equations (8') to (10') below.

number

[0067] As shown above, the first term on the right-hand side of equations (8') to (10') (the multiplication term for potential V2) is precisely the net voltage value Vcorr(2,1) to Vcorr(2,3) that should be output for each thermistor element SC(2,1) to SC(2,3) that is not covered by the shielding SLD (i.e., is irradiated with electromagnetic waves IR) when potential V2 is applied to the wax wire A2. Furthermore, the first term on the right-hand side of each of these equations (the multiplication term for potential V2) reflects the effects of both the self-heating due to the current (sense current) resulting from the difference (potential V2) between the potential applied to the wax wire A2 during measurement operation and the potential applied to the wax wire A2 during base voltage acquisition operation, and the effects of electromagnetic waves IR. Furthermore, the second term on the right-hand side of each equation (the multiplication term for potential V3) is the net voltage value Vcorr(1,1)~Vcorr(1,3) that should be output for each thermistor element SC(1,1)~SC(1,3) covered by the shield SLD (shielded from electromagnetic waves IR) when potential V3 is applied to the wax wire A1. Also, the second term on the right-hand side of each equation (the multiplication term for potential V3) reflects the effect of self-heating due to the current (sense current) caused by the difference (potential V3) between the potential applied to the wax wire A1 during measurement operation and the potential applied to the wax wire A1 during base voltage value acquisition operation. Since the polarity of potential V2 and the polarity of potential V3 are opposite, the second term on the right-hand side of each equation (the multiplication term for potential V3) can be said to be a term that cancels out the effect of self-heating of the thermistor element SC(i,j) due to the effect of this sense current. Furthermore, the third to fifth terms on the right-hand side of equation (8') (linear combination terms of the multiplication term of potential V1) are precisely the base voltage values ​​Vbase(1) used for correction to eliminate the effect when potential V1 is applied to the wax wires A1 to A3 for temperature adjustment. Similarly, the third to fifth terms on the right-hand side of equation (9') are the base voltage values ​​Vbase(2) used for correction, and the third to fifth terms on the right-hand side of equation (10') are the base voltage values ​​Vbase(3) used for correction. Thus, the relationships exemplified in equations (8') to (10') can be understood as equation (4') with the addition of a term that cancels out the effect of self-heating of the thermistor element SC(i,j) due to the sense current, and the validity of this embodiment can be understood.

[0068] With the element array circuit 3 configured in this way, and the electromagnetic wave sensor 100 equipped therewith, the effect of self-heating of the thermistor element SC(i,j) due to the sense current can be canceled, so that the intensity distribution of electromagnetic wave IR radiated from the target Tg can be measured with even greater accuracy. Furthermore, although a smaller the heat capacity of the thermistor element SC(i,j) enables highly sensitive and sharp detection of electromagnetic wave IR, using such a thermistor element SC(i,j) can result in a large amount of heat generation even with the same sense current. Therefore, even in such cases, by adopting the configuration and operation of this embodiment, it is possible to achieve even more sensitive and accurate measurement of electromagnetic wave IR.

[0069] [Fourth Embodiment] Figure 12 is a flowchart outlining another example of operation of the electromagnetic wave sensor 100 according to this disclosure. Figures 13 to 15 are flowcharts showing parts of the procedure for an example of operation of the element array circuit 1 according to this disclosure. As shown in Figure 12, the electromagnetic wave sensor 100 of this embodiment can be operated by a procedure substantially equivalent to the flowchart in the example of operation of the electromagnetic wave sensor 100 shown in Figure 3, except that steps S70 and S80 are performed between steps S30 and S40, and step S50'' is performed instead of step S50.

[0070] Furthermore, as shown in Figures 12 and 13, in steps S70 and S80, after the "base voltage value acquisition operation" of step S30 is performed, the control unit CTRL2 closes the shutter 40, and the "offset voltage value acquisition operation" is performed in a state where electromagnetic waves from the shutter 40 having a radiation surface with a substantially uniform temperature (corresponding to an example of a "substantially uniform temperature reference object" in this disclosure) are irradiated onto the thermistor elements SC(1,1) to SC(m,n) (in a state where electromagnetic waves IR from the measurement target Tg are not irradiated onto all thermistor elements SC(i,j)). In step S70, the same operation as the measurement operation in step S40 is performed except that the shutter 40 is closed, and based on the result, the correction offset voltage value Voff(i,j) is acquired. In step 70 as in step 40, the temperature of the thermistor elements SC(1,1) to SC(m,n) is maintained within a predetermined range. Examples of suitable shutters 40 include aluminum plates treated with black anodizing. Furthermore, a "radiant surface with a substantially uniform temperature" refers to a surface in which the overall temperature range (the difference between the maximum and minimum temperature) falls within the temperature resolution of the electromagnetic wave sensor 100. More specifically, for example, it can be a surface in which the overall temperature range (the difference between the maximum and minimum temperature) is 0.05°C or less.

[0071] As shown in Figure 13, in step S70, the control unit CTRL2 first assigns "1" to i (i=1) as a definition process, and repeats the processes of steps S71 to S74 until the subscript i=m. First, in step S71, the same process as step S41 shown in Figure 6 is performed, and in step S72, in much the same manner as step S42 shown in Figure 6, the control unit CTRL2 measures the voltage value Vo(j)[V] output from each operational amplifier OP(j), and the control unit CTRL2 acquires the voltage value Vo(j)[V] as the reference voltage value Vmeas2(i,j) corresponding to the thermistor element SC(i,j) connected to the corresponding column line Bj. Next, in step S73, in the same manner as step S43 shown in Figure 6, the control unit CTRL2 turns all switches SW1(i) ON (closed: conducting state) and turns all switches SW2(i) OFF (closed: non-conducting state). Next, the control unit CTRL2 performs a definition process by incrementing i by one (i=i+1), and in step S74, it determines whether i>m. If "No", it returns to step S71, and if "Yes", it proceeds to step S80.

[0072] Furthermore, in step S80, as shown in Figure 14, the control unit CTRL2 first substitutes "1" for i and j as a definition process (i=1, j=1), and repeats the processes in steps S81 to S83 until the subscripts i=m and j=n. That is, in step S81, the offset voltage value Voff(i,j) for offset correction corresponding to each thermistor element SC(i,j) is calculated by taking the difference between the reference voltage value Vmeas2(i,j) corresponding to each thermistor element SC(i,j) when the potential V1a+V2 is applied to the wax wire Ai and the average value Vave of all reference voltage values ​​Vmeas2(1,1) to Vmeas2(m,n) (see equation (11) below). Voff(i,j)=Vmeas2(i,j)-Vave …(11)

[0073] Next, the control unit CTRL2 performs a definition process by incrementing j by 1 (j=j+1), and in step S82, it determines whether j>n. If "No", it returns to S81, and if "Yes", it performs a definition process by incrementing i by 1 (i=i+1) and resetting j to 1 (j=1). Then, in step S83, the second control unit CTRL2 determines whether i>m. If "No", it returns to S81, and if "Yes", it moves to step S40, where it performs the measurement operation of the measurement target Tg and obtains the measured voltage value Vmeas1(i,j) corresponding to each thermistor element SC(i,j). Then, in step S51'' of step S50 shown in Figure 15, when the potential V1a+V2 is applied to the wax wire Ai of setting i, and the potential V1a is applied to the wax wires A other than setting i, the difference between the measured voltage value Vmeas1(i,j) corresponding to each thermistor element SC(i,j) and the correction base voltage value Vbase(j) used to eliminate the effect when the potential V1a is applied to the wax wires A1~Am for temperature adjustment is obtained as the offset voltage value Voff(i,j) acquired in step S80. The correction is performed using the following method. More specifically, the net voltage value Vcorr(i,j) that should be output for each thermistor element SC(i,j) when a potential V2 is applied to the wax wire Ai is calculated by subtracting the offset voltage value Voff(i,j) from the difference between the measured voltage value Vmeas1(i,j) and the base voltage value Vbase(j) (see equation (12) below). Then, steps S52, S53 and step S60 described above are performed in order to complete the process. Vcorr(i,j)= Vmeas1(i,j)-Vbase(j)-Voff(i,j) …(12)

[0074] With the element array circuit 1 configured in this way, and the electromagnetic wave sensor 100 equipped therewith, even if there are manufacturing variations in the resistance value of the thermistor element SC(i,j), correction is also performed using the offset voltage value Voff(i,j) obtained by actual measurement using a surface with virtually uniform temperature, thereby reducing measurement errors caused by such individual manufacturing differences. As a result, the measurement accuracy in electromagnetic wave IR measurement from the measurement target Tg can be further improved.

[0075] [Fifth Embodiment] Figure 16 is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the fifth embodiment of this disclosure. The element array circuit 4 is configured similarly to the element array circuit 1 shown in Figure 1, except that each of the element array circuits 4 further comprises a plurality of second resistors R2(i,j) connected in series with a corresponding thermistor element SC(i,j), a wax wire Ai, and a column wire Bj. These second resistors R2(i,j) correspond to an example of a "resistor" according to this disclosure.

[0076] Generally, if there is manufacturing variation in the resistance values ​​of the thermistor elements SC(i,j), more current tends to flow through the wiring (mains) to which thermistor elements SC have lower resistance values. If the thermistor element SC is an NTC thermistor with a negative temperature coefficient of resistance, the thermistor element SC will self-heat, causing its temperature to rise and its resistance to decrease further. This can lead to even more current concentrating on the mains of the thermistor element, potentially causing it to break. In contrast, as in this embodiment, when a second resistor R2 is connected to the thermistor element SC, they act as negative feedback resistors, increasing the voltage generated by the second resistor R2 and decreasing the voltage applied to thermistor element SC. As a result, self-heating of the thermistor element SC is reduced, and ultimately, the current converges to a value determined by the balance between the resistance values ​​of both the thermistor element SC and the second resistor R2, preventing the thermistor element SC from being destroyed by self-heating.

[0077] Here, from the viewpoint of enabling the second resistor R2 to function as such a negative feedback resistor, if the rate of change of the resistance value of the second resistor R2 with respect to temperature is smaller than that of the thermistor element SC (for example, less than 1 / 100 of the rate of change of the thermistor element SC), the effect of preventing current concentration is sufficiently enhanced. Furthermore, even if the resistance value of the second resistor R2 is greater than 1 / 1000 of the resistance value of the thermistor element SC, the effect of preventing current concentration is sufficiently enhanced. Moreover, it is even more preferable if the resistance value of the second resistor R2 is smaller than the resistance value of the thermistor element SC. Conversely, if the resistance value of the second resistor R2 is greater than the resistance value of the thermistor element SC, the voltage applied to the thermistor element SC becomes smaller, resulting in a decrease in the rate of change caused by electromagnetic waves IR included in the sensor output, and a tendency for sensitivity to decrease. Note that these relationships between the second resistor R2 and thermistor element SC are for use at room temperature (25°C) and when no voltage is applied to either.

[0078] [Sixth Embodiment] Figure 17 is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the sixth embodiment of this disclosure. The element array circuit 5 is configured similarly to the element array circuit 1 shown in Figure 1, except that it includes current mirror circuits CR(1) to CR(n) instead of operational amplifiers OP(1) to OP(n), an ammeter ATj connected between each current mirror circuit CR(j) and the control unit CTRL2, and a power supply VT4 that applies a potential V4 such that one of the two transistors constituting each current mirror circuit CR(j) operates in the saturation region.

[0079] In the element array circuit 5 configured in this way, in step S30 shown in Figures 3 and 5, a "base current value acquisition operation" (corresponding to an example of a "base output value acquisition operation" in this disclosure) is performed instead of a "base voltage value acquisition operation". That is, in step S32, the control unit CTRL2 measures the current value Io(j)[A] output from each current mirror circuit CR(j) using an ammeter ATj, and the control unit CTRL2 acquires the current value Io(j)[A] as a base current value Ibase(j) (corresponding to an example of a "base output value" in this disclosure) for correction to thermistor elements SC(1,j)~SC(m,j) connected to the corresponding column line Bj. Furthermore, in the "measurement operation" of step S40 shown in Figures 3 and 6, the control unit CTRL2 measures the current Io(j)[A] output from each current mirror circuit CR(j) using an ammeter ATj, and the control unit CTRL2 acquires the current value Io(j)[A] as the measured current value Imeas1(i,j) (corresponding to an example of the "measured output value" in this disclosure) corresponding to the thermistor element SC(i,j) connected to the corresponding column line Bj.

[0080] Then, in the "Measurement Output Value Correction Operation" of step S50 shown in Figures 3 and 7, the net current value Icorr(i,j) that should be output corresponding to each thermistor element SC(i,j) when a potential V1a+V2 is applied to the wax wire Ai of setting i, and a potential V1a is applied to wax wire A other than setting i is calculated by taking the difference between the measurement current value Imeas1(i,j) and the correction base current value Ibase(j) used to eliminate the effect when a potential V1a is applied to wax wires A1~Am for temperature adjustment (see formula (13) below). Icorr(i,j)=Imeas1(i,j)-Ibase(j) …(13)

[0081] With the element array circuit 5 configured in this way, and the electromagnetic wave sensor 100 equipped therewith, the temperature of the thermistor element SC(i,j) used to measure the electromagnetic wave IR from the target Tg can be easily and accurately maintained within a predetermined temperature range by adjusting the potential V1 through the temperature control operation performed by the control unit CTRL1. In this state, the control unit CTRL2 measures the electromagnetic wave IR from the target Tg, effectively eliminating the influence of ambient temperature at that time. This allows for measurement of electromagnetic wave IR from the target Tg in a wide range of ambient temperature environments while keeping the readout and processing circuits for the output signal simple.

[0082] [Seventh Embodiment] Figure 18 is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the seventh embodiment of this disclosure. The element array circuit 6 is configured similarly to the element array circuit 1 shown in Figure 1, except that some of the thermistor elements SC(i,j) (here, thermistor elements SC(1,1) to SC(m,1) connected to column wire B1) are covered with a shielding SLD that blocks electromagnetic waves IR, thereby shielding them from electromagnetic waves IR from the measurement target Tg, and that it includes subtraction circuits Sub(2) to Sub(n) connected to the operational amplifier OP(1) connected to the column wire B1 and the other operational amplifiers OP(2) to OP(n), respectively, and these subtraction circuits Sub(2) to Sub(n) are connected to the control unit CTRL2. In the seventh embodiment and the eighth and ninth embodiments described later, column wire B1 corresponds to an example of a "third wiring extending in the second direction" according to this disclosure, column wires B2 to Bn correspond to an example of a "second wiring" according to this disclosure, thermistor elements SC(1,1) to SC(m,1) covered with shield SLD correspond to an example of a "second thermistor element" according to this disclosure, and thermistor elements SC(1,2) to SC(m,n) other than thermistor elements SC(1,1) to SC(m,1) correspond to an example of a "first thermistor element" according to this disclosure.

[0083] In the element array circuit 6 configured in this way, the subtraction circuits Sub(2) to Sub(n) output the voltage difference between the output voltage of the operational amplifier OP corresponding to the thermistor element SC (active cell) that is not covered by the shield SLD and the output voltage of the operational amplifier OP corresponding to the thermistor element SC (blind cell) that is covered by the shield SLD to the control unit CTRL2.

[0084] The following describes the operation of the element array circuit 6 as an example, where the thermistor element SC(i,j) array is 3 rows x 3 columns (m=3,n=3) and measurement is performed using thermistor elements SC(1,2) and SC(1,3) connected to the wax wire A1.

[0085] Here, first, in step S30 shown in Figures 3 and 5, the "base voltage value acquisition operation" is replaced with the "base correction value acquisition operation" (corresponding to an example of the "base output value acquisition operation" in this disclosure). Here, the control circuit CTRL2 first turns on switches SW1(1) to SW1(3) and turns off switches SW2(1) to SW2(m), similar to step S31 shown in Figure 5, and applies the adjusted potential V1a from the power supply VT1 to all the wires A1 to A3. At this time, the output voltage Vm1 from op-amp OP(1) (output corresponding to the blind cell) and the output voltages Vm2 and Vm3 from op-amps OP(2) and OP(3) (outputs corresponding to the active cells) are expressed as shown in equations (14) to (16) below.

[0086]

number

[0087] Voltages Vm2 and Vm3 are voltage values ​​output through column lines B2 and B3, respectively (corresponding to an example of the "first base output value" in this disclosure), and voltage Vm1 is a voltage value output through column line B1 (corresponding to an example of the "second base output value" in this disclosure). Then, instead of step S32 shown in Figure 5, these output voltages Vm1 to Vm3 are input to subtraction circuits Sub(2) and Sub(3), and the calculation results, differential voltages Vm2-Vm1 and Vm3-Vm1, are output to control circuit CTRL2 as differential base voltage values ​​ΔVbase[1,2] and ΔVbase[1,3] (corresponding to an example of the "differential base output value" in this disclosure), and control circuit CTRL2 obtains the differential base voltage values ​​ΔVbase[1,2] and ΔVbase[1,3]. These differential base voltage values ​​are expressed by the following equations (17) and (18).

number

[0088] Next, the control unit CTRL2 controls the opening and closing of switches SW1(1) to SW1(3) and switches SW2(1) to SW2(3) in the same manner as in step S41 shown in Figure 6, applying a potential V1a + V2 to the wax wire Ai of setting i (i=1), and applying a potential V1a to the wax wire A other than setting i, thereby performing an operation corresponding to the "measurement operation" of step S40 shown in Figures 3 and 6. At this time, the output voltage Vm1 from op-amp OP(1) (output corresponding to the blind cell) and the output voltages Vm2 and Vm3 from op-amps OP(2) and OP(3) (outputs corresponding to the active cell) are expressed as shown by the following equations (19) to (21).

number

[0089] Voltages Vm2 and Vm3 are voltage values ​​output through column lines B2 and B3, respectively (corresponding to an example of the "first measurement output value" in this disclosure), and voltage Vm1 is a voltage value output through column line B1 (corresponding to an example of the "second measurement output value" in this disclosure). Then, instead of step S42 shown in Figure 6, these output voltages Vm1 to Vm3 are input to subtraction circuits Sub(2) and Sub(3), and the calculation results, differential voltages Vm2-Vm1 and Vm3-Vm1, are output to control circuit CTRL2 as differential measurement voltage values ​​ΔVmeas[1,2] and ΔVmeas[1,3] (corresponding to an example of the "differential measurement output value" in this disclosure), and control circuit CTRL2 acquires the differential measurement voltage values ​​ΔVmeas[1,2] and ΔVmeas[1,3]. These differential measurement voltage values ​​are expressed by the following equations (22) and (23).

[0090]

number

[0091] Then, as the "measurement output value correction operation" in step S50 shown in Figures 3 and 7, the net voltage values ​​Vcorr[1,2] and Vcorr[1,3] are calculated by taking the difference between the differential measurement voltage value ΔVmeas[1,2] and the differential base voltage value ΔVbase[1,2], and the difference between the differential measurement voltage value ΔVmeas[1,3] and the differential base voltage value ΔVbase[1,3]. These net voltage values ​​are expressed by the following equations (24) and (25).

[0092]

number

[0093] Thus, the net voltage values ​​Vcorr[1,2] and Vcorr[1,3] consist only of the difference between the active cells, thermistor elements SC(1,2) and SC(1,3), and the blind cell, thermistor element SC(1,1), respectively. From this, an output can be obtained in which the effects of ambient temperature and sense current are canceled out.

[0094] [Eighth Embodiment] Figure 19 is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the eighth embodiment of this disclosure. The element array circuit 7 is configured similarly to the element array circuit 6 shown in Figure 18, except that it includes current mirror circuits CR(1) to CR(n) and ammeters AT2 to ATn connected between the current mirror circuits CR(2) to CR(n) and the control unit CTRL2, instead of operational amplifiers OP(1) to OP(n) and subtraction circuits Sub(2) to Sub(n), and also includes a power supply VT4 that applies a potential V4 such that one of the two transistors constituting each of the current mirror circuits CR(2) to CR(n) operates in the saturation region.

[0095] In the element array circuit 7 configured in this way, the current mirror circuits CR(1) to CR(n), arranged as shown in the figure, output the difference between the output current from column line B corresponding to the thermistor element SC (active cell) that is not covered by the shield SLD and the output current from column line B corresponding to the thermistor element SC (blind cell) that is covered by the shield SLD, to the control unit CTRL2.

[0096] The following describes the operation of the element array circuit 7 as an example, where the thermistor element SC(i,j) array is 3 rows x 3 columns (m=3,n=3), and measurement is performed using thermistor elements SC(1,2) and SC(1,3) connected to the wax wire A1.

[0097] Here, first, in step S30 shown in Figures 3 and 5, the "base voltage value acquisition operation" is replaced with the "base correction value acquisition operation" (corresponding to an example of the "base output value acquisition operation" in this disclosure). Here, the control circuit CTRL2 first turns on switches SW1(1) to SW1(3) and turns off switches SW2(1) to SW2(m), similar to step S31 shown in Figure 5, and applies the adjusted potential V1a from the power supply VT1 to all the wax wires A1 to A3. At this time, the output current Im1 from column wire B1 (output corresponding to the blind cell) and the output currents Im2 and Im3 from column wires B2 and B3 (outputs corresponding to the active cells) are expressed as shown in equations (26) to (28) below.

[0098]

number

[0099] Output currents Im2 and Im3 are current values ​​output through column lines B2 and B3, respectively (corresponding to an example of the "first base output value" in this disclosure), and output current Im1 is the current value output through column line B1 (corresponding to an example of the "second base output value" in this disclosure). Then, instead of step S32 shown in Figure 5, of these output currents Im1 to Im3, output current Im1 is input to current mirror circuit CR(1), and output currents Im2 and Im3, along with the output current -Im1 from current mirror circuit CR(1), are input to current mirror circuits CR(2) and CR(3), respectively. In other words, the differential current Im2-Im1 is input to current mirror circuit CR(2), and the differential current Im3-Im1 is input to current mirror circuit CR(3). Then, the difference currents Im2-Im1 and Im3-Im1, respectively, from the ammeters AT2 and AT3 are output to the control circuit CTRL2 as difference base current values ​​ΔIbase[1,2] and ΔIbase[1,3] (corresponding to an example of the "difference base output value" in this disclosure), and the control circuit CTRL2 acquires the difference base current values ​​ΔIbase[1,2] and ΔIbase[1,3]. These difference base current values ​​are expressed by the following equations (29) and (30).

number

[0100] Next, the control unit CTRL2 controls the opening and closing of switches SW1(1) to SW1(3) and switches SW2(1) to SW2(3) in the same manner as in step S41 shown in Figure 6, applying the potential V1a + V2 to the wax wire Ai of setting i (i=1), and applying the potential V1a to the wax wires A other than setting i, thereby performing an operation corresponding to the "measurement operation" of step S40 shown in Figures 3 and 6. At this time, the output current Im1 from column wire B1 (output corresponding to the blind cell) and the output currents Im2 and Im3 from column wires B2 and B3 (outputs corresponding to the active cell) are expressed as shown by the following equations (31) to (33).

number

[0101] Output currents Im2 and Im3 are current values ​​output through column lines B2 and B3, respectively (corresponding to an example of the "first measurement output value" in this disclosure), and output current Im1 is the current value output through column line B1 (corresponding to an example of the "second measurement output value" in this disclosure). Then, instead of step S42 shown in Figure 6, of these output currents Im1 to Im3, output current Im1 is input to current mirror circuit CR(1), and output currents Im2 and Im3, along with the output current -Im1 from current mirror circuit CR(1), are input to current mirror circuits CR(2) and CR(3), respectively. In other words, the differential current Im2-Im1 is input to current mirror circuit CR(2), and the differential current Im3-Im1 is input to current mirror circuit CR(3). Then, the difference currents Im2-Im1 and Im3-Im1, respectively, from the ammeters AT2 and AT3 are output to the control circuit CTRL2 as difference measurement current values ​​ΔImeas[1,2] and ΔImeas[1,3] (corresponding to an example of "difference measurement output value" in this disclosure), and the control circuit CTRL2 acquires the difference measurement current values ​​ΔImeas[1,2] and ΔImeas[1,3]. These difference measurement current values ​​are expressed by the following equations (34) and (35).

[0102]

number

[0103] Then, as the "measurement output value correction operation" in step S50 shown in Figures 3 and 7, the net current values ​​Icorr[1,2] and Icorr[1,3] are calculated by taking the difference between the differential measurement current value ΔImeas1[1,2] and the differential base current value ΔIbase[2], and the difference between the differential measurement current value ΔImeas1[1,3] and the differential base current value ΔIbase[1,3]. These net current values ​​are expressed by the following equations (36) and (37).

[0104]

number

[0105] Thus, the net current values ​​Icorr[1,2] and Icorr[1,3] consist only of the difference between the active cells, thermistor elements SC(1,2) and SC(1,3), and the blind cell, thermistor element SC(1,1), respectively. From this, an output can be obtained in which the effects of ambient temperature and sense current are canceled out.

[0106] [Ninth Embodiment] Figure 20 is a schematic circuit diagram showing an example of the configuration of an element array circuit according to the ninth embodiment of this disclosure. The element array circuit 8 is configured similarly to the element array circuit 6 shown in Figure 18, except that it includes a current mirror circuit CR(1) instead of the operational amplifier OP(1) and subtraction circuits Sub(2) to Sub(n), and that the difference between the output current from column lines B2 to Bn and the output current from the current mirror circuit CR(1) is input to the negative input terminals of each of the operational amplifiers OP(2) to OP(n).

[0107] In the element array circuit 8 configured in this way, the current mirror circuit CR(1) and operational amplifiers OP(2) and OP(n), arranged as shown in the figure, convert the voltage obtained from the difference between the output current from column line B corresponding to the thermistor element SC (active cell) that is not covered by the shield SLD and the output current from column line B corresponding to the thermistor element SC (blind cell) that is covered by the shield SLD, and output the voltage to the control unit CTRL2.

[0108] The following describes the operation of the element array circuit 8 as an example, where the thermistor element SC(i,j) array is 3 rows x 3 columns (m=3,n=3), and measurement is performed using thermistor elements SC(1,2) and SC(1,3) connected to the wax wire A1.

[0109] Here, first, in step S30 shown in Figures 3 and 5, the "base correction value acquisition operation" (corresponding to an example of the "base output value acquisition operation" in this disclosure) is performed instead of the "base voltage value acquisition operation". Here, the control circuit CTRL2 first turns on switches SW1(1) to SW1(3) and turns off switches SW2(1) to SW2(m), similar to step S31 shown in Figure 5, and applies the adjusted potential V1a from the power supply VT1 to all the wax wires A1 to A3. At this time, the output current Im1 from column wire B1 (output corresponding to the blind cell) and the output currents Im2 and Im3 from column wires B2 and B3 (outputs corresponding to the active cells) are expressed in the same way as equations (26) to (28) above (reproduced below).

[0110]

number

[0111] Then, instead of step S32 shown in Figure 5, of these output currents Im1 to Im3, output current Im1 is input to the current mirror circuit CR(1), and output currents Im2 and Im3, along with the output current -Im1 from the current mirror circuit CR(1), are input to the operational amplifiers OP(2) and OP(3), respectively. In other words, the differential current Im2-Im1 is input to operational amplifier OP(2), and the differential current Im3-Im1 is input to operational amplifier OP(3). The differential currents Im2-Im1 and Im3-Im1 are the difference (differential base current values ​​ΔIbase[1,2], ΔIbase[1,3]) between the current value output through column lines B2 and B3 (corresponding to an example of the "first base output value" in this disclosure) and the current value output through column line B1 (corresponding to an example of the "second base output value" in this disclosure). Then, the differential base current values ​​ΔIbase[1,2] and ΔIbase[1,3] from the operational amplifiers OP(2) and OP(3) are converted into differential base voltage values ​​ΔVbase[1,2] and ΔVbase[1,3] (corresponding to an example of the "differential base output value" in this disclosure) and output to the control circuit CTRL2, which then obtains the differential base voltage values ​​ΔVbase[1,2] and ΔVbase[1,3]. The differential base voltage value ΔVbase[1,2] is the voltage obtained by multiplying the differential current Im2-Im1 by the resistance value RX(2) of resistor R1(2), and the differential base voltage value ΔVbase[1,3] is the voltage obtained by multiplying the differential current Im3-Im1 by the resistance value RX(3) of resistor R1(3). These differential base voltage values ​​are expressed by the following equations (38) and (39).

number

[0112] Next, the control unit CTRL2 controls the opening and closing of switches SW1(1) to SW1(3) and switches SW2(1) to SW2(3) in the same manner as in step S41 shown in Figure 6, applying the potential V1a + V2 to the wax wire Ai of setting i (i=1), and applying the potential V1a to the wax wires A other than setting i, thereby performing an operation corresponding to the "measurement operation" of step S40 shown in Figures 3 and 6. At this time, the output current Im1 from column wire B1 (output corresponding to the blind cell) and the output currents Im2 and Im3 from column wires B2 and B3 (outputs corresponding to the active cell) are expressed in the same manner as equations (31) to (33) above (reproduced below).

number

[0113] Then, instead of step S42 shown in Figure 6, of these output currents Im1 to Im3, output current Im1 is input to the current mirror circuit CR(1), and output currents Im2 and Im3, along with the output current -Im1 from the current mirror circuit CR(1), are input to the operational amplifiers OP(2) and OP(3), respectively. In other words, the differential current Im2-Im1 is input to operational amplifier OP(2), and the differential current Im3-Im1 is input to operational amplifier OP(3). The differential currents Im2-Im1 and Im3-Im1 are the difference between the current value output through column lines B2 and B3 (corresponding to an example of the "first measurement output value" in this disclosure) and the current value output through column line B1 (corresponding to an example of the "second measurement output value" in this disclosure) (differential measurement current values ​​ΔImeas[1,2], ΔImeas[1,3]). Then, the differential measurement current values ​​ΔImeas[1,2] and ΔImeas[1,3] from the operational amplifiers OP(2) and OP(3) are converted into differential measurement voltage values ​​ΔVmeas[1,2] and ΔVmeas[1,3] (corresponding to an example of the "differential measurement output value" in this disclosure) and output to the control circuit CTRL2, which then acquires the differential measurement voltage values ​​ΔVmeas[1,2] and ΔVmeas[1,3]. The differential measurement voltage value ΔVmeas[1,2] is the voltage obtained by multiplying the differential current Im2-Im1 by the resistance value RX(2) of resistor R1(2), and the differential measurement voltage value ΔVmeas[1,3] is the voltage obtained by multiplying the differential current Im3-Im1 by the resistance value RX(3) of resistor R1(3). These differential measurement voltage values ​​are expressed by the following equations (40) and (41).

[0114]

number

[0115] Then, as the "measurement output value correction operation" in step S50 shown in Figures 3 and 7, the net voltage values ​​Vcorr[1,2] and Vcorr[1,3] are calculated by taking the difference between the differential measurement voltage value ΔVmeas[1,2] and the differential base voltage value ΔVbase[1,2], and the difference between the differential measurement voltage value ΔVmeas[1,3] and the differential base voltage value ΔVbase[1,3]. These net voltage values ​​are expressed by the following equations (42) and (43).

[0116]

number

[0117] Thus, the net voltage values ​​Vcorr[1,2] and Vcorr[1,3] consist only of the difference between the active cells, thermistor elements SC(1,2) and SC(1,3), and the blind cell, thermistor element SC(1,1), respectively. From this, an output can be obtained in which the effects of ambient temperature and sense current are canceled out.

[0118] [Tenth Embodiment] In the element array circuits 1 to 8 of the embodiments described above (excluding element array circuit 3), the configuration may have only one wax wire A1 as the wax wire Ai. In this case, the thermistor element SC(i,j) will be only the thermistor element SC(1,j) corresponding to wax wire A1, and the wax wire selection unit SA will have one switch SW1(1) and one switch SW2(1). In each element array circuit with such a configuration, the procedure can be carried out in accordance with the operation procedure shown in Figures 3 to 7, except that the selection of wax wire Ai is not performed.

[0119] For example, in the case where the element array circuit 1 (Figure 1) according to the first embodiment has only one wax wire A1, the operation procedure is as follows: First, in step S10 shown in Figure 3, an "initialization operation" is performed, and in the following step S20, a "temperature control operation" is performed on the thermistor element SC(1,j). Next, in step S30, with the adjusted potential V1a applied to the wax wire A1, a "base voltage value acquisition operation" is performed to obtain the correction base voltage value Vbase(j) for the thermistor element SC(1,j). Then, in step S40, with the potential V1a+V2 applied to the wax wire A1 from power supply VT1 and power supply VT2, a "measurement operation" is performed to obtain the measured voltage value Vmeas1(1,j) corresponding to the thermistor element SC(1,j). Then, in step S50, the "measurement output value correction operation" is performed as a calculation process to calculate the net voltage value Vcorr(1,j) that should be output for each thermistor element SC(1,j) when a potential V2 is applied to the wax wire A1 (see equation (4) above).

[0120] Alternatively, in the case where the element array circuit 6 (Figure 18) according to the seventh embodiment has only one wax wire A1, the operation procedure is as follows: First, in step S10 shown in Figure 3, an "initialization operation" is performed, and in the following step S20, a "temperature control operation" is performed on the thermistor elements SC(1,1) to SC(1,n). Next, in step S30, with the adjusted potential V1a applied to the wax wire A1, a "base correction value acquisition operation" is performed to obtain the differential base voltage value ΔVbase[1,j](j≧2) for the thermistor element SC(1,j). Then, in step S40, with the potential V1a+V2 applied to the wax wire A1 from power supply VT1 and power supply VT2, an operation equivalent to a "measurement operation" is performed to obtain the differential measurement voltage value ΔVmeas[1,j](j≧2). Then, in step S50, the "measurement output value correction operation" is performed as a calculation process to calculate the net voltage value Vcorr(1,j)(j≧2) that should be output for each thermistor element SC(1,j)(j≧2) when a potential V2 is applied to the wax wire A1 (see equations (24) and (25) above).

[0121] The embodiments described above with reference to specific examples are intended to facilitate understanding of this disclosure and are not intended to limit its interpretation. In other words, this disclosure is not limited to these specific examples, and any modifications made to these examples by those skilled in the art are also included within the technical scope of this disclosure, as long as they retain the features of this disclosure. Furthermore, the elements, arrangements, materials, conditions, shapes, dimensions, scales, etc., of each of the aforementioned specific examples are not limited to those exemplified unless otherwise specified and can be modified as appropriate. Moreover, the elements of each of the aforementioned specific examples can be combined in any way as appropriate, as long as no technical inconsistencies arise. That is, for example, the number of wires for the wax wire Ai and column wire Bj is not particularly limited and can be set arbitrarily. For example, there may be only one column wire Bj instead of multiple. Also, for example, the number of operational amplifiers OP may be less than the number of column wires Bj, and a configuration may be used to switch between multiple column wires B(j) sequentially connected one by one to the negative input terminal of a single operational amplifier OP using an appropriate switch.

[0122] Furthermore, the power supplies VT1 and VT2 may be provided inside or outside the element array circuit 1. In addition, instead of resistor R1, a capacitor (capacitive element) connected in parallel to the operational amplifier OP(j) in the same way as resistor R1 may be used. Even in this case, the current flowing through column line B(j) can be converted into a voltage. Also, the "temperature control operation" performed in step S20 may be performed using an output corresponding to the current value of the current flowing through each column line B (for example, the output voltage from each operational amplifier OP or the measured current value of the current flowing through each column line B) instead of the current value of the current flowing through wax line A. Furthermore, in step S50, the calculation shown in equation (4) ("measurement output value correction operation") was performed after the acquisition of the measured voltage value Vmeas1(i,j) for all wax line A was completed, but the calculation shown in equation (4) ("measurement output value correction operation") may be performed sequentially while scanning and acquiring each measured voltage value Vmeas1(i,j). Furthermore, in step S60, instead of performing an image data conversion operation to convert the data into image data indicating temperature, an operation to simply convert the data into temperature data or electromagnetic wave intensity information may be performed. [Explanation of Symbols]

[0123] 1,2,3,4,5,6,7,8…Element array circuit, 11…Sensor section, 12…Peripheral circuit section, 20…Substrate, 21…Housing wall, 22…Getter material, 30…Optical system, 40…Shutter, 41…Drive unit, 100… Electromagnetic wave sensor, Ai...Wax wire (first wiring), AT, ATj...Ammeter, Bj...Column wire, CR...Current mirror circuit, CTRL1...First control unit, CTRL2...Second control unit, IR...Electromagnetic wave, OP...Operational amplifier, R1...First resistor, R2...Second resistor (resistor), S...Internal space, SA...Wax wire selection unit, SC...Thermistor element, SLD...Shield, Sub...Subtraction circuit, SW1, SW2...Switch, Tg...Measurement target, VT1...Power supply (first power supply), VT2...Power supply (other power supply), VT1 and VT2...(second power supply), VT3...Power supply (yet another power supply), VT1 and VT3 (third power supply), VT4...Power supply

Claims

1. Multiple first wirings extending in the first direction, One or more second wirings extending in the second direction, Each of the following is a plurality of first thermistor elements connected to one of the first wirings and one of the second wirings, A first power supply configured to supply a first potential, A second power supply configured to supply a second potential different from the first potential, Control unit and Equipped with, The control unit, As a temperature control operation, while the first thermistor element is not irradiated with electromagnetic waves from the object to be measured, the first potential is applied to the plurality of first wirings to cause current to flow through the first thermistor element, and by adjusting the first potential, the first thermistor element is maintained at a temperature within a predetermined range. As part of the base output value acquisition operation, with the first thermistor element being irradiated with electromagnetic waves from the object to be measured, the adjusted first potential is applied to the plurality of first wirings, and the base output value output through the second wiring is acquired. As a measurement operation, with the first thermistor element being irradiated with electromagnetic waves from the object to be measured, the second potential is applied to one first wire selected from the plurality of first wires, and the adjusted first voltage is applied to the first wires other than the selected one, and the measurement output value output through the second wire is obtained. As a measurement output value correction operation, the difference between the measurement output value and the base output value is taken. Element array circuit.

2. A first wiring extending in the first direction, One or more second wirings extending in the second direction, Each of these comprises one or more first thermistor elements connected to one of the first wirings and one of the second wirings, A first power supply configured to supply a first potential, A second power supply configured to supply a second potential different from the first potential, Control unit and Equipped with, The control unit, As a temperature control operation, while the first thermistor element is not irradiated with electromagnetic waves from the object to be measured, the first potential is applied to one of the first wirings to cause current to flow through the first thermistor element, and by adjusting the first potential, the first thermistor element is maintained at a temperature within a predetermined range. As part of the base output value acquisition operation, with the first thermistor element being irradiated with electromagnetic waves from the object to be measured, the adjusted first potential is applied to one of the first wirings, and the base output value output through the second wiring is acquired. As part of the measurement operation, while the first thermistor element is irradiated with electromagnetic waves from the object to be measured, the second potential is applied to one of the first wires, and the measurement output value output from the second wire is acquired. As a measurement output value correction operation, the difference between the measurement output value and the base output value is taken. Element array circuit.

3. The element array circuit according to claim 1 or 2, wherein the second power supply comprises the first power supply and another power supply connected in series with the first power supply.

4. The first power supply and the second power supply are provided for each of the plurality of first wirings, The control unit maintains the first thermistor element at a temperature within the predetermined range by adjusting the first potential for each of the first wires during the temperature control operation. The element array circuit according to claim 1.

5. Multiple first wirings extending in the first direction, One or more second wirings extending in the second direction, A third wiring extending in the second direction, Each of the following is a plurality of first thermistor elements connected to one of the first wirings and one of the second wirings, Each of the multiple second thermistor elements is connected to one of the first wirings and the third wiring, and is shielded from electromagnetic waves from the object being measured. A first power supply configured to supply a first potential, A second power supply configured to supply a second potential different from the first potential, Control unit and Equipped with, The control unit, As a temperature control operation, while the first thermistor element is not irradiated with electromagnetic waves from the object to be measured, the first potential is applied to the plurality of first wirings to cause current to flow through the first thermistor element and the second thermistor element, and by adjusting the first potential, the first thermistor element and the second thermistor element are maintained at a temperature within a predetermined range. As part of the base output value acquisition operation, with the first thermistor element irradiated with electromagnetic waves from the object to be measured, the adjusted first potential is applied to the plurality of first wirings, and the differential base output value resulting from the difference between the first base output value output through the second wiring and the second base output value output through the third wiring is acquired. As a measurement operation, with the first thermistor element irradiated with electromagnetic waves from the object to be measured, the second potential is applied to one first wire selected from the plurality of first wires, and the adjusted first voltage is applied to the first wires other than the selected one, and a difference measurement output value is obtained, which is the difference between the first measurement output value output through the second wire and the second measurement output value output through the third wire. As a measurement output value correction operation, the difference between the differential measurement output value and the differential base output value is taken. Element array circuit.

6. A first wiring extending in the first direction, One or more second wirings extending in the second direction, A third wiring extending in the second direction, Each of these comprises one or more first thermistor elements connected to one of the first wirings and one of the second wirings, A second thermistor element is connected to the aforementioned first wiring and the aforementioned third wiring and is shielded from electromagnetic waves from the object to be measured, A first power supply configured to supply a first potential, A second power supply configured to supply a second potential different from the first potential, Control unit and Equipped with, The control unit, As a temperature control operation, while the first thermistor element is not irradiated with electromagnetic waves from the object to be measured, the first potential is applied to one of the first wirings to cause current to flow through the first thermistor element and the second thermistor element, and by adjusting the first potential, the first thermistor element and the second thermistor element are maintained at a temperature within a predetermined range. As part of the base output value acquisition operation, with the first thermistor element irradiated with electromagnetic waves from the object to be measured, the adjusted first potential is applied to one of the first wirings, and the differential base output value resulting from the difference between the first base output value output through the second wiring and the second base output value output through the third wiring is acquired. As part of the measurement operation, with the first thermistor element irradiated with electromagnetic waves from the object to be measured, the second potential is applied to one of the first wires, and a difference measurement output value is obtained, which is the difference between the first measurement output value output through the second wire and the second measurement output value output through the third wire. As a measurement output value correction operation, the difference between the differential measurement output value and the differential base output value is taken. Element array circuit.

7. A third wiring extending in the first direction, Each is connected to one of the second wirings and the third wiring, and includes one or more second thermistor elements shielded from electromagnetic waves from the object being measured, A third power supply configured to supply a third potential, Furthermore, The polarity of the potential difference obtained by subtracting the first potential from the second potential is opposite to the polarity of the potential difference obtained by subtracting the first potential from the third potential. The control unit, In the temperature control operation described above, the first potential is applied to the third wiring to cause current to flow through the second thermistor element, and the first potential is adjusted to maintain the second thermistor element at a temperature within the predetermined range. In the base output value acquisition operation, the adjusted first potential is applied to the third wiring, and the base output value output through the second wiring is acquired. In the measurement operation described above, the third potential is applied to the third wiring, and the measurement output value output through the second wiring is obtained. The element array circuit according to claim 1 or 2.

8. The element array circuit according to claim 7, wherein the third power supply comprises the first power supply and yet another power supply connected in series with the first power supply.

9. The control unit, As part of the offset voltage value acquisition operation, while the first thermistor element is irradiated with electromagnetic waves from a reference object with substantially uniform temperature, the second potential is applied to one first wire selected from the plurality of first wires, and the adjusted first voltage is applied to the first wires other than the selected one, and the reference output value output through the second wire is acquired, and the offset output value, which is the difference between the respective reference output value and the average value of all reference output values, is calculated. In the measurement output value correction operation, the difference between the measurement output value and the base output value is corrected using the offset output value. The element array circuit according to claim 1.

10. The element array circuit according to claim 1, further comprising a plurality of resistors connected in series with a corresponding first thermistor, a first wiring, and a second wiring, each of which is connected to a corresponding first thermistor element.

11. An element array circuit according to any one of claims 1, 2, 5, and 6, A shutter that switches between irradiating the first thermistor element with electromagnetic waves from the object to be measured and not irradiating it, An electromagnetic wave sensor equipped with the following features.

12. Multiple first wirings extending in the first direction, One or more second wirings extending in the second direction, Each of the following is a plurality of first thermistor elements connected to one of the first wirings and one of the second wirings, A first power supply configured to supply a first potential, A second power supply configured to supply a second voltage different from the first potential, Control unit and A control method for an element array circuit comprising, The control unit, A temperature control operation is performed to maintain the first thermistor element at a temperature within a predetermined range by applying the first potential to the plurality of first wirings to cause current to flow through the first thermistor element and adjusting the first potential, while the first thermistor element is not irradiated with electromagnetic waves from the object to be measured. With the first thermistor element being irradiated with electromagnetic waves from the object to be measured, the adjusted first potential is applied to the plurality of first wirings, and the base output value is obtained by obtaining the base output value output through the second wiring. A measurement operation in which, while the first thermistor element is irradiated with electromagnetic waves from the object to be measured, the second potential is applied to one first wire selected from the plurality of first wires, and the adjusted first voltage is applied to the first wires other than the selected one first wire, and the measurement output value output through the second wire is obtained, A measurement output value correction operation that takes the difference between the measurement output value and the base output value, A method for controlling an element array circuit to perform the following actions.

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