JP6358080B2 - Pressure sensor - Google Patents

Description

  The present invention relates to a pressure sensor including a plurality of sensor circuits formed on a substrate.

  In various fields such as a display device and a sensor device, a transistor circuit having a transistor including a semiconductor layer is widely used. For example, a transistor circuit is used as a drive circuit for driving a light emitting element of an organic EL display device or as a sensor circuit for detecting a sensor signal in a pressure sensor device (see, for example, Patent Documents 1 to 5). The transistor circuit is generally provided in the form of a transistor substrate comprising a substrate and a plurality of transistor circuits formed on the substrate.

  Conventionally, inorganic semiconductor materials such as silicon, gallium arsenide, and indium gallium arsenide have been used as semiconductor materials for transistors. On the other hand, in recent years, research on transistors using organic semiconductor materials has been actively conducted. Organic semiconductor materials can generally be formed on a substrate at a lower temperature than inorganic semiconductor materials. For this reason, a flexible plastic substrate etc. can be utilized as a board | substrate. This makes it possible to provide a lightweight semiconductor element that is stable against mechanical shock. In addition, since an organic semiconductor material can be formed on a substrate using a coating process such as a printing method, a larger number of organic transistors can be efficiently formed on the substrate than when an inorganic semiconductor material is used. Is possible. For this reason, there is a possibility that the manufacturing cost of the semiconductor element can be lowered. For these reasons, organic semiconductor materials are expected to be applied to drive circuits such as organic EL and electronic paper, or electronic tags.

  For example, Patent Documents 3 and 4 propose that a pressure sensor is configured by arranging a large number of organic transistors using an organic semiconductor material in a matrix on a substrate. In this case, one of the source electrode and the drain electrode of each organic transistor is electrically connected to a pressure sensitive body whose electric resistance and capacitance change according to the applied pressure. Further, the other of the source electrode and the drain electrode of each organic transistor is connected to a bit line for taking out a detection signal including information on the electric resistance and capacitance of the pressure sensitive body. According to the pressure sensor configured as described above, it is possible to calculate the distribution of pressure applied to the pressure sensor by reading the change in the detection signal from each organic transistor taken out via the bit line. it can.

JP-A-60-211986 JP 2013-068563 A JP 2013-068562 A JP 2012-053050 A JP-A-2005-150146

  By the way, in the pressure sensor in which the pressure sensitive body and the transistor are combined, it is desirable that the current does not flow more than necessary in the pressure range larger than the pressure range to be measured as indicated by the solid line L1 in FIG. However, when the present inventor actually verified using a conventional pressure sensor, as shown by the solid line L2 in FIG. 6, in the pressure range larger than the pressure range to be measured, the index rather increases as the pressure increases. It was found that the current increases functionally.

  When a large current flows in a pressure range larger than the pressure range to be measured, the following problem occurs. That is, (1) the current stress of the transistor and the pressure sensitive body increases. (2) Power consumption increases. (3) An excessive load is applied to the drive circuit.

  The present invention has been devised to pay attention to the above problems and to effectively solve them. The objective of this invention is providing the pressure sensor which can suppress that the electric current more than necessary flows in the pressure range larger than the pressure range made into a measuring object.

The pressure sensor according to the present invention comprises:
A pressure sensor that generates a detection signal according to an applied pressure,
A substrate;
A plurality of sensor circuits formed on the substrate;
With
The sensor circuit is
A first electrode;
An insulating layer provided to cover the first electrode;
A pressure-sensitive body having elasticity provided on the insulating layer;
A second electrode provided on the pressure sensitive body;
Have
The pressure sensitive body is configured such that the electrical resistance or capacitance of the pressure sensitive body changes according to the pressure applied to the pressure sensitive body,
An opening is formed in a part of the insulating layer,
The first electrode and the pressure sensitive body are opposed to each other with the opening interposed therebetween.
In the pressure sensor according to the present invention, the sensor circuit further includes a transistor including a gate electrode, a source electrode, and a drain electrode, and one of the source electrode and the drain electrode is electrically connected to the first electrode. In addition, the other of the source electrode and the drain electrode may be electrically connected to a bit line that transmits a detection signal including information related to the electric resistance or capacitance of the pressure sensitive body.
In the pressure sensor according to the present invention,
The gate electrode is provided on the substrate;
A gate insulating film is provided on the base material so as to cover the gate electrode,
The source electrode and the drain electrode are provided on the gate insulating film so as to face each other with a certain distance therebetween,
A semiconductor layer is provided between the source electrode and the drain electrode so as to be in contact with both the source electrode and the drain electrode;
The first electrode is provided on the gate insulating film so as to be in contact with one of the source electrode and the drain electrode,
The insulating layer may be provided so as to cover the source electrode, the drain electrode, the semiconductor layer, and the first electrode.
In the pressure sensor according to the present invention,
The source electrode and the drain electrode are provided on the base material so as to face each other at a constant interval,
A semiconductor layer is provided between the source electrode and the drain electrode so as to be in contact with both the source electrode and the drain electrode;
A gate insulating film is provided on the base material so as to cover the source electrode, the drain electrode, and the semiconductor layer;
The gate electrode and the first electrode are provided on the gate insulating film,
The insulating layer is provided so as to cover the gate electrode and the first electrode,
One of the source electrode and the drain electrode and the first electrode may be electrically connected via a through hole formed in a part of the gate insulating film.
In the pressure sensor according to the present invention, the bit line may be electrically connected to the other of the source electrode and the drain electrode in at least two of the sensor circuits.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the electric current beyond necessity flows in the pressure range larger than the pressure range made into a measuring object.

FIG. 1 is a plan view showing a pressure sensor according to an embodiment of the present invention. 2 is a longitudinal sectional view showing an example of a layer configuration of a sensor circuit in the pressure sensor of FIG. FIG. 3 is a diagram for explaining a circuit configuration of the sensor circuit of FIG. FIG. 4 is a drawing corresponding to FIG. 2 and is a longitudinal sectional view showing another example of the layer configuration of the sensor circuit. FIG. 5 is a graph showing the correlation between the pressure applied in the pressure sensor according to the present embodiment and the current. FIG. 6 is a graph showing the correlation between the pressure applied in the conventional pressure sensor and the current.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings attached to the present specification, for the sake of illustration and ease of understanding, the scale, the vertical / horizontal dimension ratio, and the like are appropriately changed and exaggerated from those of the actual ones. Further, in this specification, the terms “substrate” and “film” are not distinguished from each other based only on the difference in designation. For example, the “substrate” is a concept including a member that can be called a sheet or a film. Furthermore, as used in this specification, the shape and geometric conditions and the degree thereof are specified, for example, terms such as “orthogonal”, length and angle values, etc. are not limited to strict meaning and are similar. The interpretation should include the extent to which the functions of can be expected.

  FIG. 1 is a plan view showing a pressure sensor according to an embodiment of the present invention.

  As shown in FIG. 1, the pressure sensor 20 includes a base material 21 and a plurality of sensor circuits 30 formed on the base material 21.

  In the illustrated example, the base material 21 includes a pair of first sides 22a extending along the first direction D1, a pair of second sides 22b extending along the second direction D2 orthogonal to the first direction D1, Has a rectangular outer shape. The plurality of sensor circuits 30 are arranged in a matrix along the first direction D1 and the second direction D2. On the base material 21, a plurality of terminal portions 24 electrically connected to the sensor circuit 30 are arranged side by side along the outer edge 22 of the base material 21.

  The material which comprises the base material 21 is not specifically limited as long as the sensor circuit 30 and the terminal part 24 can be supported appropriately. For example, the base material 21 may be a flexible substrate having flexibility or a rigid substrate having no flexibility.

  In FIG. 1, dotted lines denoted by reference characters W1 to Wm represent word lines provided for transmitting a control signal for sequentially turning on transistors 45 described later of the sensor circuit 30. Each of the word lines W1 to Wm is electrically connected to a gate electrode 31 described later of the plurality of sensor circuits 30 arranged along the first direction D1. For example, the first word line W1 positioned on the lowermost side in the drawing of FIG. 1 is electrically connected to the gate electrodes 31 of the plurality of sensor circuits 30 arranged along the first direction D1. For this reason, when the transistor 45 included in the sensor circuit 30 is P-type, the voltage is applied to the first word line W1 so that the voltage of the gate electrode 31 with respect to the source electrode 33 of the transistor 45 becomes negative. A plurality of transistors 45 connected to one word line W1 can be turned on simultaneously.

  In FIG. 1, dotted lines denoted by reference numerals B1 to Bn indicate bit lines provided for transmitting detection signals including information on the electrical resistance and capacitance of the pressure sensitive body 38 included in each sensor circuit 30. Represents. Each of the bit lines B1 to Bn is electrically connected to a source electrode 33 (described later) of the plurality of sensor circuits 30 arranged along the second direction D2. For example, the first bit line B1 positioned on the leftmost side in FIG. 1 is electrically connected to the source electrodes 33 of the plurality of sensor circuits 30 arranged along the second direction D2. In this case, the first bit line B1 includes one transistor that is turned on by the control signals from the word lines W1 to Wm among the transistors 45 of the plurality of sensor circuits 30 connected to the first bit line B1. The detection signal extracted from 45 is transmitted.

  According to the pressure sensor 20 shown in FIG. 1, even if the number of word lines W1 to Wm and bit lines B1 to Bn is smaller than the number of sensor circuits 30, the word lines W1 to Wm and the bit lines B1 to Bn. Are arranged in a matrix, the detection signal from any sensor circuit 30 can be taken out. For this reason, the number of wirings provided on the substrate 21 can be reduced.

  As shown in FIG. 1, the bit lines B1 to Bn and the word lines W1 to Wm are connected to the corresponding terminal portions 24, respectively. Although not shown, a large-area pressure sensor device may be configured by combining a plurality of pressure sensors 20. In this case, the terminal portion 24 may be used to electrically connect the corresponding word lines W1 to Wm and the corresponding bit lines B1 to Bn to each other between a pair of adjacent pressure sensors 20.

  FIG. 2 is a longitudinal sectional view showing an example of the layer configuration of the sensor circuit 30. FIG. 3 is a diagram for explaining the circuit configuration of the sensor circuit 30.

  As shown in FIGS. 2 and 3, the sensor circuit 30 includes a first electrode 37, an insulating layer 36 provided so as to cover the first electrode 37, and a pressure-sensitive elastic material provided on the insulating layer 36. A body 38 and a second electrode 39 provided on the pressure-sensitive body 38 are included. In the example shown in FIG. 3, the second electrode 39 is connected to the ground potential, but the specific value of the potential of the second electrode 39 is particularly limited as long as the potential of the second electrode 39 is stable. There is nothing. For example, the second electrode 39 may be connected to the power supply potential.

  In the sensor circuit 30 of the present embodiment, a transistor 45 including a gate electrode 31, a source electrode 33, and a drain electrode 34 is further provided. One of the source electrode 33 and the drain electrode 34, here the drain electrode 34, is electrically connected to the first electrode 37. The other of the source electrode 33 and the drain electrode 34, here the source electrode 33, is one of the bit lines B1 to Bn for transmitting a detection signal including information on the electrical resistance or capacitance of the pressure-sensitive body 38, as shown in FIG. In the example, it is electrically connected to the first bit line B1. The gate electrode 31 is electrically connected to one of the word lines W1 to Wm that transmits a control signal for sequentially turning on the transistor 45, in the example shown in FIG. 3, to the first word line W1.

  The layer configuration of the sensor circuit 30 will be described in detail. As shown in FIG. 2, the gate electrode 31 is provided on the first surface 21 a of the base material 21, and the gate insulating film 32 is provided on the base material 21 so as to cover the gate electrode 31. Further, the source electrode 33 and the drain electrode 34 are provided on the gate insulating film 32 so as to face each other with a certain distance therebetween, and the source electrode 33 and the drain electrode 34 are in contact with both the source electrode 33 and the drain electrode 34. A semiconductor layer 35 is provided between the drain electrode 34. Further, the first electrode 37 is provided on the gate insulating film 32 so as to be in contact with one of the source electrode 33 and the drain electrode 34, here the drain electrode 34. The first electrode 37 and the drain electrode 34 may be different parts of one electrode. The insulating layer 36 is provided so as to cover the source electrode 33, the drain electrode 34, the semiconductor layer 35, and the first electrode 37.

  A pressure sensitive body 38 is provided on the insulating layer 36, and a second electrode 39 is provided on the pressure sensitive body 38. The pressure sensitive body 38 and the second electrode 39 may be provided continuously across the plurality of sensor circuits 30. That is, the pressure sensitive body 38 and the second electrode 39 may be used in common in each sensor circuit 30. Further, an overcoat layer 26 having an insulating property may be provided on the second electrode 39.

  As materials constituting the gate electrode 31, the gate insulating film 32, the source electrode 33, the drain electrode 34, the insulating layer 36, the first electrode 37, and the second electrode 39, known materials used in transistors can be used. For example, the material disclosed in Patent Document 3 described above can be used.

  As a material constituting the semiconductor layer 35, either an inorganic semiconductor material or an organic semiconductor material may be used, but an organic semiconductor material is preferably used. As the organic semiconductor material, a low molecular organic semiconductor material such as pentacene, or a high molecular organic semiconductor material such as polypyrrole can be used. More specifically, a low molecular organic semiconductor material or a high molecular organic semiconductor material disclosed in JP2013-21190A can be used. Here, the “low molecular organic semiconductor material” means, for example, an organic semiconductor material having a molecular weight of less than 10,000.

  The pressure-sensitive body 38 is configured such that the electric resistance of the pressure-sensitive body 38 in the direction in which the pressure is applied, in this case, the thickness direction, changes according to the pressure applied to the pressure-sensitive body 38. That is, in the present embodiment, the pressure sensitive body 38 is configured as a so-called pressure sensitive conductor. The pressure-sensitive conductor includes, for example, rubber such as silicone rubber and a plurality of conductive particles such as carbon added to the rubber.

In the present embodiment, as shown in FIG. 2, an opening 36 a is formed in part of the insulating layer 36. The first electrode 37 and the pressure sensitive body 38 are opposed to each other with the opening 36a interposed therebetween, and the first electrode 37 and the pressure sensitive body 38 are not in a state where no pressure is applied to the sensor circuit 30. Guaranteed to be in contact. The cross-sectional shape of the opening 36a is not particularly limited, and may be a circular shape, an elliptical shape, or a polygonal shape. The size of the opening 36a is, for example, 50 μm □ to 400 μm □. The film thickness of the insulating layer 36 is, for example, 5 μm .

  Next, the operation of the present embodiment will be described.

  First, in a state in which no pressure is applied to the sensor circuit 30, the first electrode 37 is interposed between the first electrode 37 and the pressure sensitive body 38, so that a hollow space in the insulating layer 36 and the opening 36 a is interposed. It is guaranteed that the pressure sensitive member 38 is not in contact with the pressure sensitive member 38. Thereby, generation | occurrence | production of noise can be suppressed in the state in which the pressure is not applied to the sensor circuit 30. FIG.

  Next, when pressure is applied to the sensor circuit 30, the pressure-sensitive body 38 is pressed in the thickness direction at the portion where the pressure is applied, and an opening 36 a in which a part of the pressure-sensitive body 38 is formed in the insulating layer 36. The first electrode 37 is brought into contact with the first electrode 37. The pressure sensitive body 38 is compressed in the thickness direction by being pressed between the second electrode 39 and the first electrode 37 by the predetermined pressure. As a result, the particles in the pressure sensitive body 38 come into contact with each other in the thickness direction, and the electric resistance value of the pressure sensitive body 38 in the thickness direction becomes low. Thereby, in the sensor circuit 30 including the pressure sensitive body 38 to which pressure is applied, the current flowing between the source electrode 33 and the drain electrode 34 increases. Therefore, the distribution of the pressure applied to the pressure sensor 20 can be calculated by detecting the value of the current flowing through each sensor circuit 30.

  By the way, as mentioned in the column of the problem to be solved and used by the invention, in the pressure sensor in which the pressure sensitive body and the transistor are combined, as shown by the solid line L1 in FIG. 6, the pressure range larger than the pressure range to be measured. Then, it is desirable that the current does not flow more than necessary. However, when the present inventor actually verified using a conventional pressure sensor, as shown by the solid line L2 in FIG. 6, in the pressure range larger than the pressure range to be measured, the index rather increases as the pressure increases. It was found that the current increases functionally. This is presumed to be due to the following reason. That is, when the drain electrode portion and the pressure sensitive body are in direct contact without the opening 36a as in the present embodiment, the pressure sensitive body is greatly deformed in the high pressure region. A current path is also formed in a region outside the region defined by the drain electrode portion of the pressure body, and a current that flows into the drain electrode portion through the current path in the outer region is generated. As a result, an excessive current flows.

  On the other hand, when the present inventors actually verified using the pressure sensor according to the present embodiment, it was confirmed that in the pressure range larger than the pressure range to be measured, the current did not change greatly even if the pressure increased. . This is presumed to be due to the following reason. That is, when the opening 36a exists between the first electrode 37 connected to the drain electrode 34 and the pressure sensitive body 38, a pressure of a certain level or higher is applied to the pressure sensitive body 38 pushed into the opening 36a. It is suppressed. As a result, the current does not change greatly even if the pressure increases.

  As described above, according to the present embodiment, in the pressure range larger than the pressure range to be measured, the current does not change greatly even when the pressure is increased, that is, in the pressure range larger than the pressure range to be measured. It is possible to suppress the flow of more current than necessary. Thereby, current stress of the transistor and the pressure sensitive body can be reduced, and power consumption can be reduced. Further, it is possible to prevent an excessive load from being applied to the drive circuit.

  Further, according to the present embodiment, the insulating layer 36 is interposed between the first electrode 37 and the pressure sensitive body 38, and the first electrode 37 and the pressure sensitive body 38 are the openings formed in the insulating layer 36. Since they are opposed to each other with 36a interposed therebetween, it is guaranteed that the first electrode 37 and the pressure sensitive body 38 are not in contact with each other when no pressure is applied to the sensor circuit 30. Thereby, generation | occurrence | production of noise can be suppressed in the state in which the pressure is not applied to the sensor circuit 30. FIG.

  Various changes can be made to the above-described embodiment. Hereinafter, modified examples will be described with reference to the drawings. In the following description and the drawings used in the following description, the same reference numerals as those used for the corresponding parts in the above embodiment are used for the parts that can be configured in the same manner as the above embodiment. The duplicated explanation is omitted. In addition, when it is clear that the operational effects obtained in the above-described embodiment can be obtained in the modified example, the description thereof may be omitted.

  FIG. 4 is a drawing corresponding to FIG. 2, and is a longitudinal sectional view showing another example of the layer configuration of the sensor circuit 30 ′.

  In the sensor circuit 30 ′ illustrated in FIG. 4, the source electrode 33 and the drain electrode 34 of the transistor 45 are provided on the first surface 21 a of the base material 21 so as to face each other with a certain distance therebetween. The semiconductor layer 35 is provided between the source electrode 33 and the drain electrode 34 so as to be in contact with both the source electrode 33 and the drain electrode 34.

  The gate insulating film 32 is provided on the first surface 21 a of the base material 21 so as to cover the source electrode 33, the drain electrode 34, and the semiconductor layer 35.

  The gate electrode 31 and the first electrode 37 of the transistor 45 are respectively provided on the gate insulating film 32, and the insulating layer 36 is provided on the gate insulating film 32 so as to cover the gate electrode 31 and the first electrode 37. It has been.

  One of the source electrode 33 and the drain electrode 34, here the drain electrode 34 and the first electrode 37, are electrically connected through a through hole 32 a formed in a part of the gate insulating film 32. In addition, the 1st electrode 37 may be filled in the whole region in the through-hole 32a, or may be provided only on the wall surface of the through-hole 32a.

  A pressure sensitive body 38 is provided on the insulating layer 36, and a second electrode 39 is provided on the pressure sensitive body 38. The pressure sensitive body 38 and the second electrode 39 may be provided continuously across the plurality of sensor circuits 30 ′. That is, the pressure sensitive body 38 and the second electrode 39 may be used in common in each sensor circuit 30 '. Further, an overcoat layer 26 having an insulating property may be provided on the second electrode 39.

  In the present embodiment, as shown in FIG. 4, an opening 36 a is formed in a part of the insulating layer 36. The first electrode 37 and the pressure sensitive body 38 are opposed to each other with the opening 36a therebetween, and the first electrode 37 and the pressure sensitive body 38 are in a state where no pressure is applied to the sensor circuit 30 ′. Guaranteed to be contactless.

  The circuit configuration of the sensor circuit 30 ′ having such a layer configuration is the same as the circuit configuration (see FIG. 3) of the sensor circuit 30 in the above-described embodiment. Therefore, a pressure sensor including the sensor circuit 30 ′ shown in FIG. 4 can provide the same operational effects as those of the above-described embodiment.

  In the above-described embodiment, the source electrode 33 is electrically connected to any one of the bit lines B1 to Bn for transmitting the detection signal, and the drain electrode 34 is electrically connected to the first electrode 37. An example is shown. However, the present invention is not limited to this, and the drain electrode 34 is electrically connected to any one of the bit lines B1 to Bn that transmits the detection signal, and the source electrode 33 is electrically connected to the first electrode 37. It may be.

  In the above-described embodiment, the pressure-sensitive body 38 is a so-called pressure-sensitive conductor in which the electrical resistance of the pressure-sensitive body 38 changes according to the pressure applied to the pressure-sensitive body 38. An example is shown. However, as long as information corresponding to the pressure applied to the pressure sensitive body can be extracted, the specific configuration of the pressure sensitive body 38 is not particularly limited. For example, the pressure sensitive body 38 may be configured such that the capacitance changes according to the pressure applied to the pressure sensitive body 38.

  Further, an adhesive layer may be interposed between the pressure sensitive body 38 and the insulating layer 36. Alternatively, the insulating layer 36 itself may have adhesiveness to the pressure sensitive body 38. In these cases, the pressure-sensitive body 38 is firmly held by the insulating layer 36, so that the pressure-sensitive body 38 is opened by an opening 36 a of the insulating layer 36 due to gravity or vibration when no pressure is applied to the sensor circuit 30. It can suppress falling in.

  Note that the disclosed invention is not limited to the individual embodiments described above. Each embodiment can be appropriately combined as long as the processing contents do not contradict each other.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to this Example.

The pressure sensor 20 according to the above-described embodiment was created under the following conditions.
Size of the opening 36a: 50 μm □ to 400 μm □
Film pressure of insulating layer 36: 5 μm

  Next, the correlation between the pressure applied to the created pressure sensor 20 and the current density was measured. The measurement results are shown in FIG. In FIG. 5, the horizontal axis represents pressure, and the vertical axis represents current density.

The following can be seen from FIG. That is, when setting the pressure range to be measured in ^{1N / cm 2 ~10N / cm 2} , the pressure sensor size is 150 [mu] m □ following opening, greater pressure range than the pressure range to be measured, i.e. 10N In the pressure range of / cm ² or more, the current density does not change greatly, that is, the flow of more current than necessary is suppressed. Therefore, when setting the pressure range to be measured in ^{1N / cm 2 ~10N / cm 2} , it is desirable that the size of the opening and the 150 [mu] m □ or less.

On the other hand, for example, the pressure range to be measured when set to ^{1N / cm 2 ~15N / cm 2} , the size of the opening may be set to 150μm □ ~400μm □.

20 pressure sensor 21 base material 22 outer edge 22a first side 22b second side 24 terminal part 26 overcoat layer 30 sensor circuit 31 gate electrode 32 gate insulating film 32 through hole 33 source electrode 34 drain electrode 35 semiconductor layer 36 insulating layer 36a opening Part 37 first electrode 38 pressure sensitive body 39 common electrode 45 transistors W1 to Wm word lines B1 to Bn bit lines

Claims (5)

A pressure sensor that generates a detection signal according to an applied pressure,
A substrate;
A plurality of sensor circuits formed on the substrate;
With
The sensor circuit is
A first electrode;
An insulating layer provided to cover the first electrode;
A pressure-sensitive body having elasticity provided on the insulating layer;
A second electrode provided on the pressure sensitive body;
Have
The pressure sensitive body is configured such that the electrical resistance or capacitance of the pressure sensitive body changes according to the pressure applied to the pressure sensitive body,
An opening is formed in a part of the insulating layer,
The pressure sensor, wherein the first electrode and the pressure sensitive body are opposed to each other with the opening interposed therebetween. The sensor circuit further includes a transistor including a gate electrode, a source electrode, and a drain electrode,
One of the source electrode and the drain electrode is electrically connected to the first electrode,
2. The other of the source electrode and the drain electrode is electrically connected to a bit line that transmits a detection signal including information related to electrical resistance or capacitance of the pressure sensitive body. The described pressure sensor. The gate electrode is provided on the substrate;
A gate insulating film is provided on the base material so as to cover the gate electrode,
The source electrode and the drain electrode are provided on the gate insulating film so as to face each other with a certain distance therebetween,
A semiconductor layer is provided between the source electrode and the drain electrode so as to be in contact with both the source electrode and the drain electrode;
The first electrode is provided on the gate insulating film so as to be in contact with one of the source electrode and the drain electrode,
The pressure sensor according to claim 2, wherein the insulating layer is provided so as to cover the source electrode, the drain electrode, the semiconductor layer, and the first electrode. The source electrode and the drain electrode are provided on the base material so as to face each other at a constant interval,
A semiconductor layer is provided between the source electrode and the drain electrode so as to be in contact with both the source electrode and the drain electrode;
A gate insulating film is provided on the base material so as to cover the source electrode, the drain electrode, and the semiconductor layer;
The gate electrode and the first electrode are provided on the gate insulating film,
The insulating layer is provided so as to cover the gate electrode and the first electrode,
The one of the source electrode and the drain electrode and the first electrode are electrically connected through a through hole formed in a part of the gate insulating film. Pressure sensor. 5. The pressure sensor according to claim 2, wherein the bit line is electrically connected to the other of the source electrode and the drain electrode in at least two of the sensor circuits. 6.

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