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] Embodiments of the present invention relate to sensors.

Background Art

[0002] For example, there are sensors using MEMS (Micro Electro Mechanical Systems) elements etc. In sensors, improvement of characteristics is desired.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Embodiments provide a sensor capable of improving characteristics.

Means for Solving the Problems

[0005] According to the 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 unit. The sensor element terminal of the sensor element is electrically connected to a first current source. The other end of the sensor element is set to a first reference voltage. The 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 terminal of the voltage holding circuit. The output terminal of the voltage holding circuit is electrically connected to the first input terminal of the first differential circuit. The second switch terminal of the second switch is electrically connected to the first connection point. The other end of the second switch is electrically connected to the first other input terminal of the first differential circuit. The 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 terminal 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 connected state, the first switch to a first connected state, and the second switch to a second disconnected state, and the voltage holding circuit holds the 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 disconnected state, the first switch to a first disconnected state, and the second switch to a second connected state, and the first differential circuit outputs a first difference between the first connection point voltage in the second operation and the holding voltage held by the voltage holding circuit. [Brief explanation of the drawing]

[0006] [Figure 1] Figure 1 is a block diagram illustrating a sensor according to the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view illustrating a sensor according to the first embodiment. [Figure 3] Figure 3 is a block diagram illustrating the operation of the sensor according to the first embodiment. [Figure 4] Figure 4 is a block diagram illustrating the operation of the sensor according to the first embodiment. [Figure 5] Figure 5 is a block diagram illustrating the operation of the sensor according to the first embodiment. [Figure 6] Figure 6 is a time chart illustrating the operation of the sensor according to the first embodiment. [Figure 7] Figure 7 is a block diagram illustrating a sensor according to the second embodiment. [Figure 8] Figure 8 is a block diagram illustrating the operation of the sensor according to the second embodiment. [Figure 9] Figure 9 is a block diagram illustrating the operation of the sensor according to the second embodiment. [Figure 10] Figure 10 is a block diagram illustrating the operation of the sensor according to the second embodiment. [Figure 11] Figure 11 is a schematic cross-sectional view illustrating a sensor according to an embodiment. [Figure 12] Figure 12 is a schematic plan view illustrating a sensor according to an embodiment. [Figure 13] Figure 13 is a schematic plan view illustrating a sensor according to an embodiment. [Modes for carrying out the invention]

[0007] The embodiments of the present invention will be described below with reference to the drawings. Drawings are schematic or conceptual, and the relationships between the thickness and width of each part, as well as the ratios of the sizes of different parts, are not necessarily identical to those of reality. Even when representing the same part, the dimensions and ratios may be depicted differently in different drawings. In this specification and in each figure, elements similar to those described above are denoted by the same reference numerals, and detailed explanations are omitted as appropriate.

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

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

[0010] In this example, the sensor unit 10S includes a first connection part 31Ca and a first opposing connection part 31Cb. The first connection part 31Ca is held by the first holding part 31Sa and holds the element part 10E. The first opposing connection part 31Cb is held by the first opposing holding part 31Sb and holds the element part 10E. As will be described later, these connection parts may have a meander structure. Heat conduction through these connection parts is suppressed. At least a portion of the sensor element 11 may overlap with 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 this embodiment, a voltage VS (see Figure 1) is applied pulsed to the conductive member 21. This causes the temperature of the conductive member 21 to rise. Consequently, the temperature of the sensor element 11 also rises. ofAt this time, the temperature of the sensor element 11 depends on the type and concentration of the target gas to be detected around the element part 10E. This is due to the change in thermal conductivity (heat dissipation property) depending on the type and concentration of the target gas to be detected. The temperature of the sensor element 11 when the heat dissipation property is high is lower than the temperature of the sensor element 11 when the heat dissipation property is low. The change in the temperature of the sensor element 11 can be detected as a change in the electrical resistance of the sensor element 11. For example, by detecting the change in the electrical resistance of the sensor element 11, the type and concentration of the target gas to be detected can be detected. The sensor 110 is, for example, a gas sensor. The sensor 110 is, for example, a thermal conductivity type gas sensor. The sensor element 11 is, for example, a resistance element.

[0012] In the detection of the target gas, in order to obtain high accuracy, 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 one element is used as a reference element. In this case, the number of sensor units 10S increases, and it is difficult to miniaturize the sensor. Furthermore, it is difficult to obtain a highly accurate detection result due to the difference in characteristics that occurs in the plurality of sensor units 10S.

[0013] In the embodiment, one sensor unit 10S is used. Using this sensor unit 10S, the detection result is derived from the results obtained by a plurality of operations. Thereby, it is easy to miniaturize the sensor. Furthermore, there is no deterioration in accuracy due to the difference in characteristics that occurs when a plurality of sensor units 10S are used. A highly accurate detection result can be obtained .fruit According to the embodiment, a sensor with improved characteristics can be provided.

[0014] Hereinafter, an example of the configuration of the sensor unit 10S and an example of the operation in the sensor 110 will be described. 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] As shown in Figure 1, the sensor element terminal 11a of the sensor element 11 is electrically connected to the first current source 75a (CS1). The other sensor element terminal 11b of the sensor element 11 is set to the first reference voltage Vs1. The first reference voltage Vs1 is, for example, the ground voltage (GND).

[0016] The first switch terminal e1 of the first switch S1 is electrically connected to the 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 the 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 other second switch 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 the 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 the first reference voltage Vs1 (e.g., GND). As shown in Figure 1, the circuit section 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 converts the output of the multiplexer 77a into an AD converter. exchange Yes, it is possible. The memory 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 this embodiment, the control unit 78 is capable of performing the first and second operations described below.

[0021] Figures 3 and 4 are block diagrams illustrating the operation of the sensor according to the first embodiment. Figure 3 illustrates the first action. Figure 4 illustrates the second action. As shown in Figure 3, in the first operation OP1, the control unit 78 sets the third switch S3 to the third connected state, the first switch S1 to the first connected state, and the second switch S2 to the second unconnected 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] As shown in Figure 4, in the second operation OP2, the control unit 78 sets the third switch S3 to the third disconnected state, the first switch S1 to the first disconnected state, and the second switch S2 to the second connected state. The first differential circuit 71 outputs the first difference between the first connection point voltage VC1 in the second operation OP2 and the holding voltage VH1 held by 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 is, for example, the concentration of the gas to be detected. degree The detection result corresponds to the first difference, for example, the type of gas to be detected. According to the embodiment, a highly accurate detection result can be obtained using one sensor unit 10S.

[0024] In one embodiment, the value corresponding to the first difference described above may be stored in the storage unit 77c. In another embodiment, the value corresponding to the first connection point voltage VC1 described above may be stored in the storage unit 77c. In yet another embodiment, the value corresponding to the holding voltage VH1 described above may be stored in the storage unit 77c.

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

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

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

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

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

[0030] The second difference corresponds to the temperature measurement result using the reference resistance element 10R. The circuit section 70 may output a value that corrects the first difference (detection result of the target gas) based on the second difference (temperature measurement result). For example, the concentration of the target gas is corrected for temperature. A more accurate detection result can be obtained.

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

[0032] Figure 6 is a time chart illustrating the operation of the sensor according to the first embodiment. The horizontal axis in these figures represents time tm. As shown in Figure 6, in the first operation OP1, the first switch S1 is ON (connected), the second switch S2 is OFF (disconnected), the third switch S3 is ON (connected), and the fourth switch S4 is OFF (disconnected). In the second operation OP2, the first switch S1 is OFF (disconnected), the second switch S2 is ON (connected), the third switch S3 is OFF (disconnected), and the fourth switch S4 is OFF (disconnected). 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 the first interval time TI1. For example, the pulse time TP may be between 100ms and 300ms. On the other hand, the first interval time TI1 may be between 1ms and 50ms. In this embodiment, the first interval time TI1 can be shortened. This is because the heat capacity of the element part 10E is small. 、 This is due to the ability to obtain rapid temperature changes. This, for example, enables 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 also be 1 / 10 or less of the pulse time TP. The first interval time TI1 may also be 1 / 50 or less of the pulse time TP.

[0035] As shown in Figure 6, the first time t1 is defined as the time when the third switch S3 transitions from the third connected state (on) to the third disconnected state (off) during the first operation OP1. The second time t2 is defined as the time when the second switch S2 transitions from the second disconnected state (off) to the second connected state (on) during the second operation OP2. The time from the first time t1 to the second time t2 corresponds to the first interval time TI1. The time during the first operation OP1 when the third switch S3 is in the third connected state (on) 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 Figure 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] As shown in Figure 2, at least a portion of the circuit section 70 may be provided on the base 41. In the direction from the base 41 to the element section 10E (for example, in the Z-axis direction), at least a portion of the circuit section 70 may overlap with the element section 10E.

[0039] figure 1 As shown, the substrate 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 transistors and the like. A portion of the semiconductor substrate 41s may include CMOS circuits. At least a portion of the circuit section 70 may be formed by a portion of the semiconductor substrate 41s.

[0040] (Second Embodiment) Figure 7 is a block diagram illustrating a sensor according to the second embodiment. As shown in Figure 7, the sensor 120 according to this 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 storage 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. The rest of the configuration of the sensor 120 may be the same as that of the sensor 110.

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

[0042] The control unit 78 is capable of performing the first operation OP1 and the second operation OP2. The voltage at the first connection point CP1 between the sensor element terminal 11a and the first current source 75a is defined as the first connection point voltage VC1. In the first operation OP1, the control unit 78 stores in the storage unit 77c a first value Va1 corresponding to the first connection point voltage VC1 at the first connection point CP1 when 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 when no voltage VS is applied to the conductive member 21. The circuit unit 70 can output a value corresponding to the first difference between the first value Va1 and the second value Va2. For example, this value may be output from the 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, for example, to the concentration of the gas to be detected. The value corresponding to the first difference may also correspond to the type of gas to be detected. In this embodiment, detection results can be obtained with high accuracy using a single sensor unit 10S.

[0045] The control unit 78 may also be capable of performing the third operation OP3. 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 when no voltage VS is applied to the conductive member 21. The circuit unit 70 can output a corrected value obtained by correcting the first difference based on the third value Va3. The corrected value may be output, for example, from the output unit 78a of the control unit 78.

[0046] The following describes an example of the circuit section 70 in the sensor 120. As shown in Figure 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] The first switch terminal e1 of the first switch S1 is electrically connected to the first connection point CP1. The other first switch terminal f1 of the first switch S1 is electrically connected to the first input terminal 71a of the first differential circuit 71. The other first input terminal 71b of the first differential circuit 71 is electrically connected to the second connection point CP2 of the second reference voltage Vs2 via the 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 other second switch terminal f2 of the second switch S2 is electrically connected to the second input terminal 72a of the second differential circuit 72. The other second 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 the 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 the first reference voltage Vs1 (e.g., GND).

[0050] Figures 8 and 9 are block diagrams illustrating the operation of the sensor according to the second embodiment. Figure 8 illustrates the first operation OP1. Figure 9 illustrates the second operation OP2. As shown in Figure 8, in the first operation OP1, the control unit 78 sets the first switch S1 to the first connected state, the first wiring switch Ss1 to the first wiring connected state, the second switch S2 to the second disconnected state, the second wiring switch Ss2 to the second disconnected state, and the third switch S3 to the third connected 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] As shown in Figure 9, in the second operation OP2, the control unit 78 sets the first switch S1 to the first disconnected state, the first wiring switch Ss1 to the first wiring disconnected 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 disconnected state. As a result, the first connection point voltage VC1 when no voltage VS is 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] As shown in Figure 8, the circuit section 70 may further include a third differential circuit 73, a fourth switch S4, and a third wiring switch Ss3. The fourth switch terminal e4 of the fourth switch S4 is electrically connected to the first connection point CP1. The other fourth switch terminal f4 of the fourth switch S4 is electrically connected to the third input terminal 73a of the third differential circuit 73. The third other input terminal 73b of the third differential circuit 73 is electrically connected to the second connection point CP2 via the third wiring switch Ss3. The third operation OP3 may be performed with this configuration.

[0053] Figure 10 is a block diagram illustrating the operation of the sensor according to the second embodiment. Figure 10 illustrates the third action. As already explained, 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 when no voltage VS is applied to the conductive member 21. As shown in Figure 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 no voltage VS is 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] The operation described with respect to Figure 6 may be performed in the sensor 120. 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 Figure 6). The first interval time TI1 may also be 1 / 10 or less of the pulse time TP. The first interval time TI1 may also be 1 / 20 or less of the pulse time TP.

[0056] As explained with respect to Figure 2, the sensor unit 10S may include a base body 41 and a first holding part 31Sa fixed to the base body 41. The first holding part 31Sa holds the element unit 10E. A first air gap g1 is provided between the base body 41 and the element unit 10E. This allows for a small heat capacity and enables high-speed detection.

[0057] At least a portion of the circuit section 70 may be provided on the base 41. In the direction from the base 41 to the element section 10E, at least a portion of the circuit section 70 may overlap with the element section 10E (see Figure 2).

[0058] The following describes an example of the sensor unit 10S. Figure 11 is a schematic cross-sectional view illustrating a sensor according to an embodiment. Figures 12 and 13 are schematic plan views illustrating a sensor according to an embodiment. These figures illustrate the sensor unit 10S. The configuration illustrated in these figures is applicable to sensor 110 or sensor 120. Figure 2 corresponds to the cross-sectional view along line A1-A2 in Figure 12. Figure 11 corresponds to the cross-sectional view along line B1-B2 in Figure 12. Figure 12 corresponds to the plan view in a plane including the conductive member 21. Figure 13 corresponds to the plan view in a plane including the sensor element 11.

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

[0060] As shown in Figure 12, the first direction (e.g., the X-axis direction) from the first holding portion 31Sa to the first opposing holding portion 31Sb intersects with the second direction (e.g., the Y-axis direction) from the second holding portion 32Sa to the second opposing holding portion 32Sb. The third direction (e.g., the Z-axis direction) from the substrate 41 to the element portion 10E intersects with the first and second directions. nothing It intersects with the plane.

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

[0062] As shown in Figure 13, a first film 15a and a second film 15b may be provided. A 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. These films suppress deformation of the element portion 10E, for example.

[0063] The embodiments may include the following technical proposals. (Technical proposal 1) A sensor section including an element section containing 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 unit, Equipped with, The sensor element terminal of the aforementioned sensor element is electrically connected to the first current source. The other end of the sensor element is set to a first reference voltage. The first switch terminal of the first switch is electrically connected to the 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 terminal of the voltage holding circuit. The output terminal of the voltage holding circuit is electrically connected to the first input terminal of the first differential circuit. The second switch terminal of the second switch is electrically connected to the first connection point. The other end of the second switch is electrically connected to the first other input terminal of the first differential circuit. The 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 the first and second operations. In the first operation, the control unit sets the third switch to the third connected state, the first switch to the first connected state, and the second switch to the second unconnected state, and the voltage holding circuit holds the 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 disconnected state, the first switch to a first disconnected state, and the second switch to a second connected state, and the first differential circuit outputs a first difference between the first connection point voltage in the second operation and the holding voltage held by the voltage holding circuit, the sensor.

[0064] (Technical proposal 2) The sensor according to Technical Proposal 1, wherein the 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.

[0065] (Technical proposal 3) The second operation is performed after the first operation. The first interval time from the time when the third switch transitions from the third connected state to the third disconnected state in the first operation until the second switch transitions from the second disconnected state to the second connected state in the second operation is 1 / 5 or less of the pulse time during which the third switch is in the third connected state in the first operation. 、 The sensor described in Technical Proposal 1.

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

[0067] (Technical proposal 5) The first difference is a sensor described in any one of Technical Proposals 1 to 4, corresponding to the concentration of the gas to be detected.

[0068] (Technical proposal 6) The sensor according to any one of Technical Proposals 1 to 5, wherein the circuit 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, The 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 terminal of the second differential circuit. The second other input terminal of the second differential circuit is set to a second reference voltage, as described in any one of Technical Proposals 1 to 6.

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

[0071] (Technical proposal 9) The sensor according to 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 obtains the first difference and the second difference stored in the storage unit, The sensor according to Technical Proposal 8, which 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 the second connection point between the reference resistor terminal of the reference resistor element and the second current source. The sensor according to any one of the technical proposals 7 to 10, wherein the other end of the reference resistor element is set to the first reference voltage.

[0074] (Technical proposal 12) The aforementioned sensor unit is Substrate and, A first holding portion fixed to the base, of Furthermore, The first holding portion holds the element portion, A sensor according to any one of the technical proposals 1 to 11, wherein a first air gap is provided between the substrate and the element portion.

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

[0076] (Technical proposal 14) A sensor section including an element section containing a sensor element and a conductive member, A circuit section including a memory unit and a control unit, Equipped with, The sensor element terminal of the aforementioned sensor element is electrically connected to the first current source. The other end of the sensor element is set to a first reference voltage. The control unit is capable of performing the first and second operations. In the first operation, the control unit stores in the storage unit a first value corresponding to the first connection point voltage at the first connection point between the sensor element terminal and the first current source, when 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 when the voltage is not applied to the conductive member. The circuit section is a sensor capable of outputting a value corresponding to the 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 when the voltage is not applied to the conductive member. The circuit section corrects the first difference based on the third value. of A sensor capable of outputting the output described in Technical Proposal 14.

[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. The first switch terminal of the first switch is electrically connected to the first connection point. The other end of the first switch is electrically connected to the first input terminal of the first differential circuit. The first other input terminal of the first differential circuit is electrically connected to the second connection point of the second reference voltage via the first wiring switch. The second switch terminal of the second switch is electrically connected to the first connection point. The other end of the second switch is electrically connected to the second input terminal of the second differential circuit. The second other input terminal of the second differential circuit is electrically connected to the second connection point via the second wiring switch. The 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. In the first operation, the control unit sets the first switch to a first connected state, the first wiring switch to a first wiring connected state, the second switch to a second disconnected state, the second wiring switch to a second wiring disconnected state, and the third switch to a third connected state. The control unit, in the second operation, sets the first switch to a first disconnected state, the first wiring switch to a first wiring disconnected 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 disconnected state, as described in Technical Proposal 14.

[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 when the voltage is not applied to the conductive member. The circuit section further includes a third differential circuit, a fourth switch, and a third wiring switch. The 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 third input terminal of the third differential circuit. The third other input terminal of the third differential circuit is electrically connected to the second connection point via the third wiring switch. The control unit, in the third operation, sets the first switch to the first disconnected state, the first wiring switch to the first wiring disconnected state, the second switch to the second disconnected state, the second wiring switch to the second wiring disconnected state, the third switch to the third connected state, the fourth switch to the fourth connected state, and the third wiring switch to the third wiring connected state, as described in Technical Proposal 16.

[0080] (Technical proposal 18) The sensor according to any one of Technical Proposals 14 to 17, wherein the 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 aforementioned sensor unit is Substrate and, A first holding portion fixed to the base, of Furthermore, The first holding portion holds the element portion, A sensor according to any one of the technical proposals 14 to 18, wherein a first gap is provided between the substrate and the element portion.

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

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

[0084] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configuration of each element included in the sensor, such as the substrate, sensor unit, and control unit, is included within the scope of the present invention as long as those skilled in the art can appropriately select from the known range to implement the present invention in the same way and obtain the same effects.

[0085] Furthermore, combinations of two or more elements from any of the specific examples, to the extent technically feasible, are also included within the scope of the present invention, insofar as they encompass the gist of the invention.

[0086] Furthermore, all sensors that a person skilled in the art can implement by appropriately modifying the design based on the sensors described above as embodiments of the present invention also fall within the scope of the present invention, insofar as they encompass the gist of the present invention.

[0087] Furthermore, within the scope of the concept of the present invention, a person skilled in the art could conceive of various modifications and alterations, and it is understood that such modifications and alterations also fall within the scope of the present invention.

[0088] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0089] 10E: Element part, 10R: Reference resistor element, 10Ra: Reference resistor element terminal, 10Rb: Reference resistor element other terminal, 10S: Sensor part, 11: Sensor element, 11a: Sensor element terminal, 11b: Sensor element other terminal, 15a, 15b: First and second films, 21: Conductive member, 21a: Conductive member terminal, 21b: Conductive member other terminal, 31Ca, 32Ca: First and second connection parts, 31Cb, 32Cb: First and second opposing connection parts, 31Sa, 32Sb: First and second holding parts, 31Sb, 32Sb: First and second opposing holding parts, 41: Substrate, 41i: Insulating layer, 41s: Semiconductor substrate, 70: Circuit part, 70H: Voltage holding circuit, 71-73: First to third differential circuits, 71a~73a: 1st~3rd input terminals, 71b~73b: 1st~3rd other input terminals, 75a, 75b: 1st and 2nd current sources, 76: Voltage source, 77: Processing circuit, 77a: Multiplexer, 77b: AD converter, 77c: Memory unit, 78: Control unit, 78a: Output unit, 110, 120: Sensors, CP1, CP2: 1st and 2nd connection points, OP1~OP3: 1st to 3rd operations, S1~S4: 1st to 4th switches, Ss1~Ss3: 1st to 3rd wiring switches, TI1, TI2: 1st and 2nd interval times, TP: Pulse time, VC1: 1st connection point voltage, VH1: Holding voltage, VS: Voltage, Va1~Va3: 1st to 3rd values, Vs1, Vs2: 1st and 2nd reference voltages, e1~e4: 1st to 4th switch terminals, f1~f4: 1st to 4th switch other terminals, g1: 1st air gap, t1, t2: 1st and 2nd time points

Claims

1. A sensor section including an element section containing 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 unit, Equipped with, The sensor element terminal of the aforementioned sensor element is electrically connected to the first current source. The other end of the sensor element is set to a first reference voltage. The first switch terminal of the first switch is electrically connected to the 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 terminal of the voltage holding circuit. The output terminal of the voltage holding circuit is electrically connected to the first input terminal of the first differential circuit. The second switch terminal of the second switch is electrically connected to the first connection point. The other end of the second switch is electrically connected to the first other input terminal of the first differential circuit. The 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 the first and second operations. In the first operation, the control unit sets the third switch to the third connected state, the first switch to the first connected state, and the second switch to the second unconnected state, and the voltage holding circuit holds the 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 disconnected state, the first switch to a first disconnected state, and the second switch to a second connected state, and the first differential circuit outputs a first difference between the first connection point voltage in the second operation and the holding voltage held by the voltage holding circuit, the sensor.

2. The sensor according to claim 1, wherein the 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.

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

4. The circuit section further includes a second differential circuit and a fourth switch, The 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 terminal of the second differential circuit. The sensor according to any one of claims 1 to 3, wherein the 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, In the third operation, the control unit sets the third switch to the third disconnected state, the first switch to the first disconnected state, the second switch to the second disconnected 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 and the second reference voltage in the third operation, the sensor according to claim 4.

6. The sensor according to claim 5, wherein the circuit unit 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 containing a sensor element and a conductive member, A circuit section including a memory unit and a control unit, Equipped with, The sensor element terminal of the aforementioned sensor element is electrically connected to the first current source. The other end of the sensor element is set to a first reference voltage. The control unit is capable of performing the first and second operations. In the first operation, the control unit stores in the storage unit a first value corresponding to the first connection point voltage at the first connection point between the sensor element terminal and the first current source, when 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 when the voltage is not applied to the conductive member. The circuit unit is capable of outputting a value corresponding to the first difference between the first value and the second value. 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. The first switch terminal of the first switch is electrically connected to the first connection point. The other end of the first switch is electrically connected to the first input terminal of the first differential circuit. The first other input terminal of the first differential circuit is electrically connected to the second connection point of the second reference voltage via the first wiring switch. The second switch terminal of the second switch is electrically connected to the first connection point. The other end of the second switch is electrically connected to the second input terminal of the second differential circuit. The second other input terminal of the second differential circuit is electrically connected to the second connection point via the second wiring switch. The 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. In the first operation, the control unit sets the first switch to a first connected state, the first wiring switch to a first wiring connected state, the second switch to a second disconnected state, the second wiring switch to a second wiring disconnected state, and the third switch to a third connected state. The control unit, in the second operation, sets the first switch to a first disconnected state, the first wiring switch to a first wiring disconnected 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 disconnected state.

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 when the voltage is not applied to the conductive member. The circuit section further includes a third differential circuit, a fourth switch, and a third wiring switch. The 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 third input terminal of the third differential circuit. The third other input terminal of the third differential circuit is electrically connected to the second connection point via the third wiring switch. The sensor according to claim 7, wherein the control unit, in the third operation, sets the first switch to the first disconnected state, the first wiring switch to the first wiring disconnected state, the second switch to the second disconnected state, the second wiring switch to the second wiring disconnected state, the third switch to the third connected state, the fourth switch to the fourth connected state, and the third wiring switch to the third wiring connected state.

Images