Sensor

Abstract

To provide a sensor capable of improving characteristics.SOLUTION: A sensor comprises a sensor portion and a circuit portion. The sensor portion includes an element portion including a sensor element and a conductive member. The circuit portion includes a first differential circuit, a voltage holding circuit, first to third switches, and a control portion. The sensor element is connected to a first current source. The other end of the sensor element is set to a first reference voltage. The first switch is connected to a first connection point between a sensor element end and the first current source. The other end of the first switch is connected to an input end of the voltage holding circuit. An output end of the voltage holding circuit is connected to a first input end of the first differential circuit. The second switch is connected to the first connection point. The other end of the second switch is connected to a first other input end of the first differential circuit. The third switch is connected to a voltage source. The other end of the third switch is connected to the conductive member. The other end of the conductive member is set to the first reference voltage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE The present invention relates to a sensor. [Background technology]

[0002] For example, there are sensors using MEMS (Micro Electro Mechanical Systems) elements, etc. It is desirable to improve the characteristics of sensors. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-188341 A Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments provide a sensor that allows for improved performance. [Means for solving the problem]

[0005] According to an embodiment, the sensor includes a sensor section and a circuit section. The sensor section includes an element section including a sensor element and a conductive member. The circuit section includes a first differential circuit, a voltage holding circuit, a first switch, a second switch, a third switch, and a control section. A sensor element end of the sensor element is electrically connected to a first current source. The other sensor element end of the sensor element is set to a first reference voltage. A first switch end of the first switch is electrically connected to a first connection point between the sensor element end and the first current source. The other first switch end of the first switch is electrically connected to an input end of the voltage holding circuit. An output end of the voltage holding circuit is electrically connected to a first input end of the first differential circuit. A second switch end of the second switch is electrically connected to the first connection point. The other second switch end of the second switch is electrically connected to a first other input end of the first differential circuit. A third switch end of the third switch is connected to a voltage source. The other third switch end of the third switch is electrically connected to a conductive member end of the conductive member. The other end of the conductive member is set to the first reference voltage. The control unit is capable of performing a first operation and a second operation. In the first operation, the control unit sets the third switch to a third connection state, the first switch to a first connection state, and the second switch to a second non-connection state, and the voltage holding circuit holds a first connection point voltage of the first connection point in the first operation. In the second operation, the control unit sets the third switch to a third non-connection state, the first switch to a first non-connection state, and the second switch to a second connection state, and the first differential circuit outputs a first difference between the first connection point voltage in the second operation and the held voltage held in the voltage holding circuit. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a block diagram illustrating a sensor according to the first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view illustrating the sensor according to the first embodiment. [Diagram 3] FIG. 3 is a block diagram illustrating the operation of the sensor according to the first embodiment. [Figure 4] FIG. 4 is a block diagram illustrating the operation of the sensor according to the first embodiment. [Diagram 5] FIG. 5 is a block diagram illustrating the operation of the sensor according to the first embodiment. [Figure 6] FIG. 6 is a time chart illustrating the operation of the sensor according to the first embodiment. [Figure 7] FIG. 7 is a block diagram illustrating a sensor according to the second embodiment. [Figure 8] FIG. 8 is a block diagram illustrating the operation of the sensor according to the second embodiment. [Figure 9] FIG. 9 is a block diagram illustrating the operation of the sensor according to the second embodiment. [Figure 10] FIG. 10 is a block diagram illustrating the operation of the sensor according to the second embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view illustrating the sensor according to the embodiment. [Figure 12] FIG. 12 is a schematic plan view illustrating the sensor according to the embodiment. [Figure 13] FIG. 13 is a schematic plan view illustrating the sensor according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios of each part may be different depending on the drawing. In this specification and each drawing, elements similar to those described above with reference to the previous drawings are given the same reference numerals and detailed descriptions thereof will be omitted as appropriate.

[0008] (First embodiment) FIG. 1 is a block diagram illustrating a sensor according to the first embodiment. FIG. 2 is a schematic cross-sectional view illustrating the sensor according to the first embodiment. 1, a sensor 110 according to the embodiment includes a sensor unit 10S and a circuit unit 70. The sensor unit 10S includes an element unit 10E. The element unit 10E includes a sensor element 11 and a conductive member 21.

[0009] FIG. 2 illustrates the sensor unit 10S. For example, the sensor unit 10S includes a base 41 and a first holding portion 31Sa. The first holding portion 31Sa is fixed to the base 41. The first holding portion 31Sa holds the element unit 10E. A first gap g1 is provided between the base 41 and the element unit 10E. In this example, the sensor unit 10S includes a first opposing holding portion 31Sb. The first opposing holding portion 31Sb is fixed to the base 41. The first opposing holding portion 31Sb holds the element unit 10E.

[0010] In this example, the sensor unit 10S includes a first connection portion 31Ca and a first opposing connection portion 31Cb. The first connection portion 31Ca is held by a first holding portion 31Sa and holds the element portion 10E. The first opposing connection portion 31Cb is held by a first opposing holding portion 31Sb and holds the element portion 10E. As described later, these connection portions may have a meandering structure. Heat conduction through these connection portions is suppressed. At least a portion of the sensor element 11 may overlap at least a portion of the conductive member 21. An example of the configuration of the sensor unit 10S will be described later.

[0011] In the embodiment, a voltage VS (see FIG. 1) is applied to the conductive member 21 in a pulsed manner. This causes the temperature of the conductive member 21 to rise. Accordingly, the temperature of the sensor element 11 rises. At this time, the temperature of the sensor element 11 depends on the type and concentration of the target gas around the element portion 10E. This is because the thermal conductivity (heat dissipation) changes depending on the type and concentration of the target gas. The temperature of the sensor element 11 when the heat dissipation is high is lower than the temperature of the sensor element 11 when the heat dissipation is low. The change in temperature of the sensor element 11 can be detected as a change in the electrical resistance of the sensor element 11. For example, the type and concentration of the target gas can be detected by detecting the change in the electrical resistance of the sensor element 11. The sensor 110 is, for example, a gas sensor. The sensor 110 is, for example, a thermal conduction type gas sensor. The sensor element 11 is, for example, a resistance element.

[0012] In order to obtain high accuracy in detecting the target gas, there is a reference example in which a plurality of sensor units 10S are used. In the reference example, one sensor unit 10S is used as a detection element, and another element is used as a reference element. In this case, the number of sensor units 10S increases, making it difficult to miniaturize the sensor. Furthermore, it is difficult to obtain a highly accurate detection result due to differences in characteristics that occur in the plurality of sensor units 10S.

[0013] In the embodiment, one sensor unit 10S is used. The sensor unit 10S is used to derive a detection result from the results obtained by a plurality of operations. This makes it easy to miniaturize the sensor. Furthermore, there is no deterioration in accuracy due to differences in characteristics that occur when a plurality of sensor units 10S are used. A detection result with high accuracy can be obtained. According to the calibration embodiment, a sensor capable of improving characteristics can be provided.

[0014] The following describes an example of the configuration of the sensor unit 10S and an example of the operation of the sensor 110. As shown in FIG. 1, the circuit unit 70 includes a first differential circuit 71, a voltage holding circuit 70H, a first switch S1, a second switch S2, a third switch S3, and a control unit 78.

[0015] 1, the sensor element terminal 11a of the sensor element 11 is electrically connected to a first current source 75a (CS1). The other sensor element terminal 11b of the sensor element 11 is set to a first reference voltage Vs1. The first reference voltage Vs1 is, for example, a ground voltage (GND).

[0016] The first switch terminal e1 of the first switch S1 is electrically connected to a first connection point CP1 between the sensor element terminal 11a and the first current source 75a. The other first switch terminal f1 of the first switch S1 is electrically connected to an input terminal of the voltage holding circuit 70H. The output terminal of the voltage holding circuit 70H is electrically connected to the first input terminal 71a of the first differential circuit 71.

[0017] The second switch terminal e2 of the second switch S2 is electrically connected to the first connection point CP1. The second switch other terminal f2 of the second switch S2 is electrically connected to the first other input terminal 71b of the first differential circuit 71.

[0018] The third switch terminal e3 of the third switch S3 is connected to a voltage source 76 (voltage VS). The other third switch terminal f3 of the third switch S3 is electrically connected to the conductive member terminal 21a of the conductive member 21. The other conductive member terminal 21b of the conductive member 21 is set to a first reference voltage Vs1 (for example, GND). 1, the circuit unit 70 may include a processing circuit 77. For example, the processing circuit 77 may include a multiplexer 77a, an AD converter 77b, and a storage unit 77c. The multiplexer 77a can multiplex, for example, the output of the first differential circuit 71 and the output of the second differential circuit 72. The AD converter 77b can convert the output of the multiplexer 77a into an AD signal. The storage unit 77c can store the output of the AD converter 77b.

[0019] The control unit 78 may control the first differential circuit 71, the voltage holding circuit 70H, the first switch S1, the second switch S2, the third switch S3, and the processing circuit 77.

[0020] In the embodiment, the control unit 78 is capable of carrying out a first operation and a second operation described below.

[0021] 3 and 4 are block diagrams illustrating the operation of the sensor according to the first embodiment. Figure 3 illustrates the first operation, and Figure 4 illustrates the second operation. 3, in the first operation OP1, the control unit 78 sets the third switch S3 to the third connection state, the first switch S1 to the first connection state, and the second switch S2 to the second non-connection state. The voltage holding circuit 70H holds the first connection point voltage VC1 of the first connection point CP1 in the first operation OP1.

[0022] 4, in the second operation OP2, the control unit 78 sets the third switch S3 to the third non-connected state, the first switch S1 to the first non-connected state, and the second switch S2 to the second connected state. The first differential circuit 71 outputs a first difference between the first connection point voltage VC1 in the second operation OP2 and the held voltage VH1 held in the voltage holding circuit 70H.

[0023] The first operation OP1 corresponds to, for example, a detection operation. The second operation OP2 corresponds to, for example, a reference value derivation operation. The first operation OP1 derives a value corresponding to the electrical resistance of the sensor element 11 when a voltage is applied to the conductive member 21 and the temperature of the sensor element 11 rises. The second operation OP2 derives a value (reference value) corresponding to the electrical resistance of the sensor element 11 when no voltage is applied to the conductive member 21. The difference between these values ​​(first difference) corresponds to the detection result corrected by the reference value. The first difference corresponds to, for example, the concentration of the target gas. corresponds to the detection result. The first difference may correspond to, for example, the type of the target gas. According to the embodiment, a highly accurate detection result can be obtained using one sensor unit 10S.

[0024] In an embodiment, a value corresponding to the first difference may be stored in the storage unit 77c. In an embodiment, a value corresponding to the first connection point voltage VC1 may be stored in the storage unit 77c. In an embodiment, a value corresponding to the hold voltage VH1 may be stored in the storage unit 77c.

[0025] For example, the first difference and the second difference may be stored in a storage unit 77c included in the circuit unit 70. The circuit unit 70 can obtain the first difference and the second difference stored in the storage unit 77c, and output a value obtained by correcting the first difference based on the second difference.

[0026] 1, the circuit section 70 may further include a second differential circuit 72 and a fourth switch S4. A fourth switch terminal e4 of the fourth switch S4 is electrically connected to the first connection point CP1. A fourth switch other terminal f4 of the fourth switch S4 is electrically connected to a second input terminal 72a of the second differential circuit 72. A second other input terminal 72b of the second differential circuit 72 is set to a second reference voltage Vs2.

[0027] For example, the second other input terminal 72b is electrically connected to a second connection point CP2. The second connection point CP2 is a connection point between the reference resistor terminal 10Ra of the reference resistor 10R and a second current source 75b (CS2). The reference resistor other terminal 10Rb of the reference resistor 10R is set to a first reference voltage Vs1 (e.g., GND). The second current source 75b and the reference resistor 10R generate a second reference voltage Vs2.

[0028] For example, the temperature dependency of the reference resistor 10R is low. For example, the temperature dependency of the electrical resistance of the reference resistor 10R is 10 ppm / ° C. or less. By using the reference resistor 10R, temperature compensation can be performed. For example, the control unit 78 may further be capable of performing the following third operation.

[0029] FIG. 5 is a block diagram illustrating the operation of the sensor according to the first embodiment. FIG. 5 illustrates the third operation. 5, in the third operation OP3, the control unit 78 sets the third switch S3 in the third non-connected state, the first switch S1 in the first non-connected state, the second switch S2 in the second non-connected state, and the fourth switch S4 in the fourth connected state. The second differential circuit 72 outputs a second difference between the first connection point voltage VC1 in the third operation OP3 and the second reference voltage Vs2.

[0030] The second difference corresponds to the result of measuring the temperature using the reference resistance element 10R. The circuit section 70 may be capable of outputting a value obtained by correcting the first difference (the result of measuring the temperature) based on the second difference (the result of measuring the temperature). For example, the concentration of the gas to be detected is temperature corrected. A detection result with higher accuracy can be obtained.

[0031] The above correction may be performed, for example, by correcting a value corresponding to the first difference stored in the storage unit 77c by the second difference. The temperature correction result may be stored in the storage unit 77c. The corrected result may be output from the output unit 78a of the control unit 78, for example.

[0032] FIG. 6 is a time chart illustrating the operation of the sensor according to the first embodiment. The horizontal axis of these figures is time tm. 6, in the first operation OP1, the first switch S1 is on (connected state), the second switch S2 is off (disconnected state), the third switch S3 is on (connected state), and the fourth switch S4 is off (disconnected state). In the second operation OP2, the first switch S1 is off (disconnected state), the second switch S2 is on (connected state), the third switch S3 is off (disconnected state), and the fourth switch S4 is off (disconnected state). In this example, the second operation OP2 is performed after the first operation OP1.

[0033] The on time of the third switch S3 in the first operation OP1 corresponds to the pulse time TP of the voltage applied to the conductive member 21. The time between the first operation OP1 and the second operation OP2 is defined as a first interval time TI1. For example, the pulse time TP may be about 100 ms or more and 300 ms or less. On the other hand, the first interval time TI1 may be, for example, 1 ms or more and 50 ms or less. In the embodiment, the first interval time TI1 can be shortened. This is because the heat capacity of the element unit 10E is small and a high-speed temperature change can be obtained. This enables, for example, high-speed detection.

[0034] For example, the first interval time TI1 between the first operation OP1 and the second operation OP2 may be 1 / 5 or less of the pulse time TP of the voltage VS applied to the conductive member 21 in the first operation OP1. The first interval time TI1 may be 1 / 10 or less of the pulse time TP. The first interval time TI1 may be 1 / 50 or less of the pulse time TP.

[0035] As shown in Fig. 6, the time when the third switch S3 transitions from the third connection state (on) to the third non-connection state (off) in the first operation OP1 is defined as the first time t1. The time when the second switch S2 transitions from the second non-connection state (off) to the second connection state (on) in the second operation OP2 is defined as the second time t2. The time from the first time t1 to the second time t2 corresponds to the first interval time TI1. The time when the third switch S3 is in the third connection state (on) in the first operation OP1 corresponds to the pulse time TP. For example, the first interval time TI1 may be 1 / 5 or less of the pulse time TP.

[0036] As shown in Fig. 6, in this example, the third operation OP3 is performed after the second operation OP2. The time between the second operation OP2 and the third operation OP3 is defined as the second interval time TI2. The second interval time TI2 may be 1 / 5 or less of the pulse time TP. The second interval time TI2 may be 1 / 10 or less of the pulse time TP. The second interval time TI2 may be 1 / 50 or less of the pulse time TP. High-speed detection is possible.

[0037] In the sensor 110, the circuit section 70 may include a voltage source 76. The circuit section 70 may include a first current source 75a. The circuit section 70 may include a second current source 75b. At least one of the voltage source 76, the first current source 75a, and the second current source 75b may be provided separately from the sensor 110.

[0038] 2, at least a part of the circuit section 70 may be provided on the base 41. In a direction from the base 41 to the element section 10E (for example, in the Z-axis direction), at least a part of the circuit section 70 may overlap with the element section 10E.

[0039] As shown in the figure, the base 41 may include a semiconductor substrate 41s and an insulating layer 41i. The semiconductor substrate 41s may be, for example, a silicon substrate. The insulating layer 41i is provided on the semiconductor substrate 41s. A portion of the semiconductor substrate 41s may include a transistor or the like. A portion of the semiconductor substrate 41s may include a CMOS circuit. At least a portion of the circuit unit 70 may be formed by the portion of the semiconductor substrate 41s.

[0040] Second embodiment FIG. 7 is a block diagram illustrating a sensor according to the second embodiment. 7, the sensor 120 according to the embodiment includes a sensor unit 10S and a circuit unit 70. The sensor unit 10S includes an element unit 10E. The element unit 10E includes a sensor element 11 and a conductive member 21. The circuit unit 70 includes a memory unit 77c and a control unit 78. In the sensor 120, the configuration of the circuit unit 70 is different from the configuration of the circuit unit 70 in the sensor 110. Other than this, the configuration of the sensor 120 may be similar to the configuration of the sensor 110.

[0041] In the sensor 120, the sensor element terminal 11a of the sensor element 11 is electrically connected to a first current source 75a (CS1). The other sensor element terminal 11b of the sensor element 11 is set to a first reference voltage Vs1 (for example, GND).

[0042] The control unit 78 can perform a first operation OP1 and a second operation OP2. The voltage at a first connection point CP1 between the sensor element terminal 11a and the first current source 75a is set as a first connection point voltage VC1. In the first operation OP1, the control unit 78 stores in the memory unit 77c a first value Va1 corresponding to the first connection point voltage VC1 at the first connection point CP1 in a state in which a voltage VS is applied to the conductive member 21.

[0043] In the second operation OP2, the control unit 78 stores in the storage unit 77c a second value Va2 corresponding to the first connection point voltage VC1 in a state in which the voltage VS is not applied to the conductive member 21. The circuit unit 70 is capable of outputting a value corresponding to a first difference between the first value Va1 and the second value Va2. For example, the value may be output from an output unit 78a of the control unit 78 provided in the circuit unit 70.

[0044] The value corresponding to the first difference between the first value Va1 and the second value Va2 corresponds to, for example, the concentration of the target gas. The value corresponding to the first difference may correspond to the type of the target gas. In the embodiment, a highly accurate detection result is obtained by one sensor unit 10S.

[0045] The control unit 78 may be capable of performing a third operation OP3. In the third operation OP3, the control unit 78 causes the storage unit 77c to store a third value Va3 corresponding to the first connection point voltage VC1 in a state in which the voltage VS is not applied to the conductive member 21. The circuit unit 70 is capable of outputting a correction value obtained by correcting the first difference based on the third value Va3. The correction value may be output from the output unit 78a of the control unit 78, for example.

[0046] An example of the circuit section 70 in the sensor 120 will now be described. As shown in FIG. 7, in this example, the circuit section 70 further includes a first differential circuit 71, a second differential circuit 72, a first switch S1, a second switch S2, a third switch S3, a first wiring switch Ss1, and a second wiring switch Ss2.

[0047] A first switch terminal e1 of the first switch S1 is electrically connected to a first connection point CP1. A first switch other terminal f1 of the first switch S1 is electrically connected to a first input terminal 71a of a first differential circuit 71. A first other input terminal 71b of the first differential circuit 71 is electrically connected to a second connection point CP2 of a second reference voltage Vs2 via a first wiring switch Ss1.

[0048] The second switch terminal e2 of the second switch S2 is electrically connected to the first connection point CP1. The second switch other terminal f2 of the second switch S2 is electrically connected to the second input terminal 72a of the second differential circuit 72. The second other input terminal 72b of the second differential circuit 72 is electrically connected to the second connection point CP2 via the second wiring switch Ss2.

[0049] The third switch terminal e3 of the third switch S3 is connected to a voltage source 76 (voltage VS). The other third switch terminal f3 of the third switch S3 is electrically connected to the conductive member terminal 21a of the conductive member 21. The other conductive member terminal 21b of the conductive member 21 is set to a first reference voltage Vs1 (for example, GND).

[0050] 8 and 9 are block diagrams illustrating the operation of the sensor according to the second embodiment. Fig. 8 illustrates the first operation OP1, and Fig. 9 illustrates the second operation OP2. 8, in a first operation OP1, the control unit 78 sets the first switch S1 to a first connection state, the first wiring switch Ss1 to a first wiring connection state, the second switch S2 to a second non-connection state, the second wiring switch Ss2 to a second wiring non-connection state, and the third switch S3 to a third connection state. As a result, the first connection point voltage VC1 when the voltage VS is applied to the conductive member 21 is input to the first differential circuit 71. The output of the first differential circuit 71 is stored in the storage unit 77c. In this example, the difference between the first connection point voltage VC1 and the second reference voltage Vs2 is output from the first differential circuit 71.

[0051] 9, in the second operation OP2, the control unit 78 sets the first switch S1 to the first unconnected state, the first wiring switch Ss1 to the first wiring unconnected state, the second switch S2 to the second connected state, the second wiring switch Ss2 to the second wiring connected state, and the third switch S3 to the third unconnected state. As a result, the first connection point voltage VC1 when the voltage VS is not applied to the conductive member 21 is input to the second differential circuit 72. The output of the second differential circuit 72 is stored in the storage unit 77c. In this example, the difference between the first connection point voltage VC1 and the second reference voltage Vs2 is output from the second differential circuit 72.

[0052] 8, the circuit unit 70 may further include a third differential circuit 73, a fourth switch S4, and a third wiring switch Ss3. A fourth switch end e4 of the fourth switch S4 is electrically connected to the first connection point CP1. A fourth switch other end f4 of the fourth switch S4 is electrically connected to a third input end 73a of the third differential circuit 73. A third input end 73b of the third differential circuit 73 is electrically connected to the second connection point CP2 via the third wiring switch Ss3. With such a configuration, the third operation OP3 may be performed.

[0053] FIG. 10 is a block diagram illustrating the operation of the sensor according to the second embodiment. FIG. 10 illustrates the third operation. As already described, in the third operation OP3, the control unit 78 stores in the storage unit 77c a third value Va3 corresponding to the first connection point voltage VC1 in a state in which the voltage VS is not applied to the conductive member 21. As shown in Fig. 10, for example, in the third operation OP3, the control unit 78 sets the first switch S1 to the first unconnected state, the first wiring switch Ss1 to the first wiring unconnected state, the second switch S2 to the second unconnected state, the second wiring switch Ss2 to the second wiring unconnected state, the third switch S3 to the third connected state, the fourth switch S4 to the fourth connected state, and the third wiring switch Ss3 to the third wiring connected state.

[0054] As a result, the first connection point voltage VC1 when the voltage VS is not applied to the conductive member 21 is input to the third differential circuit 73. The output of the third differential circuit 73 is stored in the storage unit 77c. In this example, the difference between the first connection point voltage VC1 and the second reference voltage Vs2 is output from the third differential circuit 73.

[0055] In the sensor 120, the operations described with reference to Fig. 6 may be performed. For example, the first interval time TI1 between the first operation OP1 and the second operation OP2 may be 1 / 5 or less of the pulse time TP of the voltage VS applied to the conductive member 21 in the first operation OP1 (see Fig. 6). The first interval time TI1 may be 1 / 10 or less of the pulse time TP. The first interval time TI1 may be 1 / 20 or less of the pulse time TP.

[0056] 2, the sensor unit 10S may include a base 41 and a first holding unit 31Sa fixed to the base 41. The first holding unit 31Sa holds the element unit 10E. A first gap g1 is provided between the base 41 and the element unit 10E. A small heat capacity is obtained, enabling high-speed detection.

[0057] At least a part of the circuit section 70 may be provided on the base 41. At least a part of the circuit section 70 may overlap the element section 10E in the direction from the base 41 to the element section 10E (see FIG. 2).

[0058] An example of the sensor unit 10S will be described below. FIG. 11 is a schematic cross-sectional view illustrating the sensor according to the embodiment. 12 and 13 are schematic plan views illustrating the sensor according to the embodiment. These figures illustrate the sensor unit 10S. The configurations illustrated in these figures are applicable to the sensor 110 or the sensor 120. FIG. 2 corresponds to a cross-sectional view taken along line A1-A2 in FIG. 12. FIG. 11 corresponds to a cross-sectional view taken along line B1-B2 in FIG. 12. FIG. 12 corresponds to a plan view in a plane including the conductive member 21. FIG. 13 corresponds to a plan view in a plane including the sensor element 11.

[0059] 11, the sensor unit 10S includes a second holding portion 32Sa and a second opposing holding portion 32Sb. The second holding portion 32Sa is fixed to the base 41. The second holding portion 32Sa holds the element unit 10E. The second opposing holding portion 32Sb is fixed to the base 41. The second opposing holding portion 32Sb holds the element unit 10E.

[0060] 12, a first direction (e.g., X-axis direction) from the first holding portion 31Sa to the first opposing holding portion 31Sb intersects with a second direction (e.g., Y-axis direction) from the second holding portion 32Sa to the second opposing holding portion 32Sb. A third direction (e.g., Z-axis direction) from the base 41 to the element portion 10E intersects with a plane including the first and second directions.

[0061] 11 and 12, in this example, the sensor unit 10S includes a second connection portion 32Ca and a second opposing connection portion 32Cb. The second connection portion 32Ca is held by the second holding portion 32Sa and holds the element unit 10E. The second opposing connection portion 32Cb is held by the second opposing holding portion 32Sb and holds the element unit 10E. These connection portions may have a meandering structure.

[0062] 13, a first film 15a and a second film 15b may be provided. The sensor element 11 is provided between the first film 15a and the second film 15b. The material of these films may be the same as the material of the sensor element 11. This film, for example, suppresses deformation of the element portion 10E.

[0063] The embodiments may include the following technical solutions. (Technical proposal 1) a sensor section including an element section including a sensor element and a conductive member; a circuit section including a first differential circuit, a voltage holding circuit, a first switch, a second switch, a third switch, and a control section; Equipped with a sensor element end of the sensor element electrically connected to a first current source; The other end of the sensor element is set to a first reference voltage; a first switch terminal of the first switch is electrically connected to a first connection point between the sensor element terminal and the first current source; the other end of the first switch is electrically connected to the input end of the voltage holding circuit; an output terminal of the voltage holding circuit is electrically connected to a first input terminal of the first differential circuit; a second switch end of the second switch electrically connected to the first connection point; the second switch other end of the second switch is electrically connected to the first other input end of the first differential circuit; a third switch terminal of the third switch is connected to a voltage source; the other end of the third switch is electrically connected to the conductive member end of the conductive member, The other end of the conductive member is set to the first reference voltage; The control unit is capable of performing a first operation and a second operation, In the first operation, the control unit sets the third switch in a third connection state, the first switch in a first connection state, and the second switch in a second non-connection state, and the voltage holding circuit holds a first connection point voltage of the first connection point in the first operation; In the second operation, the control unit sets the third switch in a third non-connected state, the first switch in a first non-connected state, and the second switch in a second connected state, and the first differential circuit outputs a first difference between the first connection point voltage in the second operation and a held voltage held in the voltage holding circuit.

[0064] (Technical proposal 2) The sensor described in technical proposal 1, wherein a first interval time between the first operation and the second operation is less than or equal to 1 / 5 of the pulse time of the voltage applied to the conductive member in the first operation.

[0065] (Technical proposal 3) The second action is performed after the first action; A first interval time from the time when the third switch transitions from the third connected state to the third non-connected state in the first operation to the time when the second switch transitions from the second non-connected state to the second connected state in the second operation is 1 / 5 or less of a pulse time during which the third switch is in the third connected state in the first operation.

[0066] (Technical proposal 4) The sensor according to technical proposal 2 or 3, wherein the first interval time is less than or equal to 1 / 10 of the pulse time.

[0067] (Technical proposal 5) The sensor according to any one of Technical Solutions 1 to 4, wherein the first difference corresponds to a concentration of a gas to be detected.

[0068] (Technical proposal 6) The sensor according to any one of Technical Solutions 1 to 5, wherein the circuit portion further includes at least one of the first current source and the voltage source.

[0069] (Technical proposal 7) the circuit section further includes a second differential circuit and a fourth switch; a fourth switch terminal of the fourth switch is electrically connected to the first connection point; the other end of the fourth switch is electrically connected to a second input end of the second differential circuit; The sensor according to any one of Technical Solutions 1 to 6, wherein a second other input terminal of the second differential circuit is set to a second reference voltage.

[0070] (Technical proposal 8) The control unit is further capable of performing a third operation, The sensor described in Technical Proposal 7, wherein, in the third operation, the control unit sets the third switch to the third unconnected state, the first switch to the first unconnected state, the second switch to the second unconnected state, and the fourth switch to the fourth connected state, and the second differential circuit outputs a second difference between the first connection point voltage in the third operation and the second reference voltage.

[0071] (Technical proposal 9) The sensor described in Technical Proposal 8, wherein the circuit section is capable of outputting a value obtained by correcting the first difference based on the second difference.

[0072] (Technical proposal 10) the circuit unit further includes a storage unit capable of storing the first difference and the second difference, The circuit unit acquires the first difference and the second difference stored in the storage unit, The sensor described in Technical Solution 8 is capable of outputting a value obtained by correcting the first difference based on the second difference.

[0073] (Technical proposal 11) the second other input terminal is electrically connected to a second connection point between a reference resistor terminal of the reference resistor and a second current source; The sensor according to any one of Technical Solutions 7 to 10, wherein the other end of the reference resistor of the reference resistor is set to the first reference voltage.

[0074] (Technical proposal 12) The sensor unit includes: A substrate; A first holding portion fixed to the base body; and the first holding portion holds the element portion, The sensor according to any one of Technical Solutions 1 to 11, wherein a first gap is provided between the base and the element portion.

[0075] (Technical proposal 13) At least a portion of the circuit unit is provided on the base, The sensor described in Technical Proposal 12, wherein at least a portion of the circuit portion overlaps with the element portion in a direction from the base to the element portion.

[0076] (Technical proposal 14) a sensor section including an element section including a sensor element and a conductive member; A circuit unit including a memory unit and a control unit; Equipped with a sensor element end of the sensor element electrically connected to a first current source; The other end of the sensor element is set to a first reference voltage; The control unit is capable of performing a first operation and a second operation, In the first operation, the control unit causes the storage unit to store a first value corresponding to a first connection point voltage of a first connection point between the sensor element terminal and the first current source in a state in which a voltage is applied to the conductive member; In the second operation, the control unit stores in the storage unit a second value corresponding to the first connection point voltage in a state in which the voltage is not applied to the conductive member; The circuitry is capable of outputting a value corresponding to a first difference between the first value and the second value.

[0077] (Technical proposal 15) The control unit is capable of performing a third operation, In the third operation, the control unit stores in the storage unit a third value corresponding to the first connection point voltage in a state in which the voltage is not applied to the conductive member; and The sensor described in Technical Proposal 14, wherein the circuit section is capable of outputting a correction value that corrects the first difference based on the third value.

[0078] (Technical proposal 16) the circuit section further includes a first differential circuit, a second differential circuit, a first switch, a second switch, a third switch, a first wiring switch, and a second wiring switch; a first switch end of the first switch electrically connected to the first connection point; the other end of the first switch is electrically connected to a first input end of the first differential circuit; a first other input terminal of the first differential circuit is electrically connected to a second connection point of a second reference voltage via the first wiring switch; a second switch end of the second switch electrically connected to the first connection point; the other end of the second switch is electrically connected to a second input end of the second differential circuit; a second other input terminal of the second differential circuit is electrically connected to the second connection point via the second wiring switch; a third switch terminal of the third switch is connected to a voltage source; the other end of the third switch is electrically connected to the conductive member end of the conductive member, The other end of the conductive member is set to the first reference voltage; the control unit, in the first operation, sets the first switch in a first connection state, sets the first wiring switch in a first wiring connection state, sets the second switch in a second non-connection state, sets the second wiring switch in a second wiring non-connection state, and sets the third switch in a third connection state; The sensor described in Technical Proposal 14, wherein, in the second operation, the control unit sets the first switch to a first unconnected state, the first wiring switch to a first wiring unconnected state, the second switch to a second connected state, the second wiring switch to a second wiring connected state, and the third switch to a third unconnected state.

[0079] (Technical proposal 17) The control unit is capable of performing a third operation, In the third operation, the control unit stores in the storage unit a third value corresponding to the first connection point voltage in a state in which the voltage is not applied to the conductive member; and the circuit section further includes a third differential circuit, a fourth switch, and a third wiring switch; a fourth switch terminal of the fourth switch is electrically connected to the first connection point; the other end of the fourth switch is electrically connected to a third input end of the third differential circuit; a third other input terminal of the third differential circuit is electrically connected to the second connection point via the third wiring switch; The sensor described in Technical Proposal 16, wherein the control unit, in the third operation, sets the first switch to the first unconnected state, sets the first wiring switch to the first wiring unconnected state, sets the second switch to the second unconnected state, sets the second wiring switch to the second wiring unconnected state, sets the third switch to the third connected state, sets the fourth switch to the fourth connected state, and sets the third wiring switch to the third wiring connected state.

[0080] (Technical proposal 18) A sensor described in any one of Technical Proposals 14 to 17, wherein a first interval time between the first operation and the second operation is 1 / 5 or less of the pulse time of the voltage applied to the conductive member in the first operation.

[0081] (Technical proposal 19) The sensor unit includes: A substrate; A first holding portion fixed to the base body; and the first holding portion holds the element portion, The sensor according to any one of Technical Solutions 14 to 18, wherein a first gap is provided between the base and the element portion.

[0082] (Technical proposal 20) At least a portion of the circuit unit is provided on the base, The sensor described in Technical Proposal 19, wherein at least a portion of the circuit portion overlaps with the element portion in a direction from the base to the element portion.

[0083] According to the embodiment, a sensor capable of improving characteristics can be provided.

[0084] The above describes the embodiment of the present invention with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configurations of each element included in the sensor, such as the base, sensor unit, and control unit, are included in the scope of the present invention as long as a person skilled in the art can implement the present invention in a similar manner and obtain similar effects by appropriately selecting them from the known range.

[0085] Furthermore, any combination of two or more elements of each of the specific examples, within the scope of technical feasibility, is also included within the scope of the present invention as long as it includes the gist of the present invention.

[0086] In addition, all sensors that can be implemented by a person skilled in the art by appropriately modifying the design based on the sensor described above as an embodiment of the present invention also belong to the scope of the present invention as long as they include the gist of the present invention.

[0087] In addition, within the scope of the concept of the present invention, a person skilled in the art may think of various modifications and alterations, and it will be understood that these modifications and alterations also fall within the scope of the present invention.

[0088] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0089] 10E: element portion, 10R: reference resistor element, 10Ra: reference resistor element end, 10Rb: other end of reference resistor element, 10S: sensor portion, 11: sensor element, 11a: sensor element end, 11b: other end of sensor element, 15a, 15b: first and second films, 21: conductive member, 21a: conductive member end, 21b: other end of conductive member, 31Ca, 32Ca: first and second connection portions, 31Cb, 32Cb: first and second opposing connection portions, 31Sa, 32Sb: first and second holding portions, 31Sb, 32Sb: first and second opposing holding portions, 41: base, 41i: insulating layer, 41s: semiconductor substrate, 70: circuit portion, 70H: voltage holding circuit, 71 to 73: first to third differential circuits, 71a to 73a: first to third input terminals, 71b to 73b: first to third other input terminals, 75a, 75b: first and second current sources, 76: voltage source, 77: processing circuit, 77a: multiplexer, 77b: AD converter, 77c: memory unit, 78: control unit, 78a: output unit, 110, 120: sensor, CP1, CP2: first and second connection points, OP1 to OP3: first to third operations, S1 to S4: first to fourth switches, Ss1 to Ss3: first to third wiring switches, TI1, TI2: first and second interval times, TP: pulse time, VC1: first connection point voltage, VH1: holding voltage, VS: voltage, Va1 to Va3: first to third values, Vs1, Vs2: first and second reference voltages, e1 to e4: first to fourth switch terminals, f1 to f4: first to fourth switch other terminals, g1: first gap, t1, t2: first and second time

Claims

1. a sensor section including an element section including a sensor element and a conductive member; a circuit section including a first differential circuit, a voltage holding circuit, a first switch, a second switch, a third switch, and a control section; Equipped with a sensor element end of the sensor element electrically connected to a first current source; The other end of the sensor element is set to a first reference voltage; a first switch terminal of the first switch is electrically connected to a first connection point between the sensor element terminal and the first current source; the other end of the first switch is electrically connected to the input end of the voltage holding circuit; an output terminal of the voltage holding circuit is electrically connected to a first input terminal of the first differential circuit; a second switch end of the second switch electrically connected to the first connection point; the second switch other end of the second switch is electrically connected to the first other input end of the first differential circuit, a third switch terminal of the third switch is connected to a voltage source; the other end of the third switch is electrically connected to the conductive member end of the conductive member, The other end of the conductive member is set to the first reference voltage, The control unit is capable of performing a first operation and a second operation, In the first operation, the control unit causes the third switch to a third connection state, the first switch to a first connection state, and the second switch to a second non-connection state, and the voltage holding circuit holds a first connection point voltage of the first connection point in the first operation; In the second operation, the control unit sets the third switch in a third non-connected state, the first switch in a first non-connected state, and the second switch in a second connected state, and the first differential circuit outputs a first difference between the first connection point voltage in the second operation and a held voltage held in the voltage holding circuit.

2. The sensor according to claim 1 , wherein a first interval time between the first operation and the second operation is equal to or less than 1 / 5 of a pulse time of a voltage applied to the conductive member in the first operation.

3. The sensor of claim 1 , wherein the first difference corresponds to a concentration of a gas to be detected.

4. the circuit section further includes a second differential circuit and a fourth switch; a fourth switch terminal of the fourth switch is electrically connected to the first connection point; the other end of the fourth switch is electrically connected to the second input end of the second differential circuit, 4. The sensor according to claim 1, wherein a second other input terminal of the second differential circuit is set to a second reference voltage.

5. The control unit is further capable of performing a third operation, 5. The sensor of claim 4, wherein, in the third operation, the control unit sets the third switch to the third unconnected state, the first switch to the first unconnected state, the second switch to the second unconnected state, and the fourth switch to a fourth connected state, and the second differential circuit outputs a second difference between the first connection point voltage in the third operation and the second reference voltage.

6. The sensor according to claim 5 , wherein the circuit portion is capable of outputting a value obtained by correcting the first difference based on the second difference.

7. a sensor section including an element section including a sensor element and a conductive member; A circuit unit including a memory unit and a control unit; Equipped with a sensor element end of the sensor element electrically connected to a first current source; The other end of the sensor element is set to a first reference voltage; The control unit is capable of performing a first operation and a second operation, In the first operation, the control unit causes the storage unit to store a first value corresponding to a first connection point voltage of a first connection point between the sensor element terminal and the first current source in a state in which a voltage is applied to the conductive member; In the second operation, the control unit stores in the storage unit a second value corresponding to the first connection point voltage in a state in which the voltage is not applied to the conductive member; The circuitry is capable of outputting a value corresponding to a first difference between the first value and the second value.

8. The control unit is capable of performing a third operation, In the third operation, the control unit stores in the storage unit a third value corresponding to the first connection point voltage in a state in which the voltage is not applied to the conductive member; and The sensor according to claim 7 , wherein the circuit portion is capable of outputting a corrected value obtained by correcting the first difference based on the third value.

9. the circuit unit further includes a first differential circuit, a second differential circuit, a first switch, a second switch, a third switch, a first wiring switch, and a second wiring switch; a first switch end of the first switch electrically connected to the first connection point; the other end of the first switch is electrically connected to a first input end of the first differential circuit; a first other input terminal of the first differential circuit is electrically connected to a second connection point of a second reference voltage via the first wiring switch; a second switch end of the second switch electrically connected to the first connection point; the other end of the second switch is electrically connected to a second input end of the second differential circuit; a second other input terminal of the second differential circuit is electrically connected to the second connection point via the second wiring switch; a third switch terminal of the third switch is connected to a voltage source; the other end of the third switch is electrically connected to the conductive member end of the conductive member, The other end of the conductive member is set to the first reference voltage, the control unit, in the first operation, sets the first switch in a first connection state, sets the first wiring switch in a first wiring connection state, sets the second switch in a second non-connection state, sets the second wiring switch in a second wiring non-connection state, and sets the third switch in a third connection state; 8. The sensor according to claim 7, wherein, in the second operation, the control unit sets the first switch to a first unconnected state, the first wiring switch to a first wiring unconnected state, the second switch to a second connected state, the second wiring switch to a second wiring connected state, and the third switch to a third unconnected state.

10. The control unit is capable of performing a third operation, In the third operation, the control unit stores in the storage unit a third value corresponding to the first connection point voltage in a state in which the voltage is not applied to the conductive member; and the circuit section further includes a third differential circuit, a fourth switch, and a third wiring switch; a fourth switch terminal of the fourth switch is electrically connected to the first connection point; the other end of the fourth switch is electrically connected to a third input end of the third differential circuit, a third other input terminal of the third differential circuit is electrically connected to the second connection point via the third wiring switch; 10. The sensor of claim 9, wherein, in the third operation, the control unit sets the first switch to the first unconnected state, the first wiring switch to the first wiring unconnected state, the second switch to the second unconnected state, the second wiring switch to the second wiring unconnected state, the third switch to the third connected state, the fourth switch to a fourth connected state, and the third wiring switch to a third wiring connected state.

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