WO2018163627A1

WO2018163627A1 - Pressure sensor

Info

Publication number: WO2018163627A1
Application number: PCT/JP2018/001886
Authority: WO
Inventors: 秀明灘
Original assignee: Ｎｉｓｓｈａ株式会社
Priority date: 2017-03-08
Filing date: 2018-01-23
Publication date: 2018-09-13
Also published as: TW201843577A; JP2018146489A

Abstract

The present invention addresses the problem of, in a pressure sensor having a plurality of electrodes arranged so as to have gaps therebetween, maintaining a characteristic in which a pressure sensing element resistance value decreases as pressure increases and making the resistance value of the pressure sensing element match the level of a thin film transistor. This pressure sensor 1 is capable of solving this problem and is such that there is an initial contact area that is the contact area where a common electrode 9 and each mountain-type pressure sensing layer 33 come into contact when the pressing force on the common electrode 9 is an initial contact force and an initial effective area that is the area of an adjustment electrode 31 overlapping with the initial contact area in a plan view and the surface area of the initial effective area is 0-50% of the surface area of the initial contact area. The adjustment electrode 31 also has a pressure measurement area outside of the initial contact area.

Description

Pressure sensor

The present invention relates to a pressure sensor, and more particularly to a pressure sensor having a large number of electrodes.

As a pressure sensor, a combination of a number of thin film transistors with a pressure sensitive resin is known (see, for example, Patent Document 1).
The pressure sensitive resin is obtained by dispersing conductive particles in an insulating resin such as silicone rubber. In the pressure-sensitive resin, when pressure is applied, the resistance value decreases due to contact between the conductive particles in the insulating resin. Thereby, the pressure applied to the pressure sensitive resin can be detected.
Many thin film transistors are arranged in a matrix and function as electrodes. This makes it possible to increase the pressure detection speed, increase the resolution, and reduce the power consumption.

Japanese Unexamined Patent Publication No. 2016-4940

There is also known a pressure sensor in which a pressure sensitive layer and a plurality of pixel electrodes are arranged to face each other with a predetermined gap.
The inventor has devised a pressure sensor having a plurality of pixel electrodes and a pressure-sensitive element composed of a mountain-shaped pressure-sensitive layer formed thereon, and further studied the problem. In this case, it is considered that the resistance of the pressure sensitive element needs to be increased in order to match the resistance value level of the thin film transistor. Therefore, the inventor studied to increase the resistance value of the pressure sensitive element by reducing the pixel electrode. However, if the pixel electrode is simply made smaller, the pixel electrode is arranged at the center of the pressure sensitive layer, so there is no portion extending outside the mountain pressure sensitive layer, and therefore the resistance value decreases as the pressure increases. The effect of the mountain-type pressure-sensitive layer cannot be obtained.

An object of the present invention is to provide a pressure sensor having a plurality of electrodes arranged with a gap between each other, while maintaining the characteristic that the resistance value of the pressure sensitive element decreases as the pressure increases. The purpose is to match the level of the thin film transistor.

Hereinafter, a plurality of modes will be described as means for solving the problem. These aspects can be arbitrarily combined as necessary.

A pressure sensor according to an aspect of the present invention includes a common electrode, a plurality of adjustment electrodes, a plurality of mountain-shaped pressure sensitive layers, and a plurality of thin film transistors.
The common electrode is formed so as to spread over one surface.
The plurality of adjustment electrodes are provided in a matrix so as to face the common electrode.
The plurality of mountain-shaped pressure sensitive layers are respectively formed on the common electrode side of the plurality of adjustment electrodes.
The plurality of thin film transistors are provided on the side opposite to the common electrode of the plurality of adjustment electrodes corresponding to the plurality of adjustment electrodes, and one or two or more adjacent ones are connected to one adjustment electrode.
When the pressing force against the common electrode is the initial contact pressure, the contact area where the common electrode and each mountain-shaped pressure-sensitive layer are in contact is the initial contact area, and the area of the adjustment electrode that overlaps the initial contact area in plan view is the initial effective area The area of the initial effective area is 0 to 50% of the area of the initial contact area.
The adjustment electrode further has a pressure measurement area outside the initial contact area.
The “mountain shape” has an apex and a peripheral portion, and includes a dome shape, a cone shape, a frustum shape, and other shapes. The mountain-shaped planar shape includes a circle, a square, and other shapes.

When the pressing force acts on the common electrode toward the mountain-shaped pressure-sensitive layer and the adjustment electrode, the contact region where the common electrode and the mountain-shaped pressure-sensitive layer are in contact is outward from the apex of the mountain-shaped pressure-sensitive layer in plan view. It spreads. At this time, the area of the portion sandwiched between the contact region and the adjustment electrode gradually increases. From the above, as the pressure increases, the resistance value of the mountain-shaped pressure sensitive layer decreases, and as a result, the detected current value increases. In particular, the sensitivity is sufficiently high even in a high pressure range, and the pressure can be accurately measured. As a result, the measurement range of pressure is widened.
Furthermore, when the area of the initial effective area is 0 to 50% of the area of the initial contact area, the adjustment electrode does not correspond to the electrode contact portion of the mountain pressure-sensitive layer at all, or the corresponding ratio is less than a predetermined value. The resistance value of the pressure sensitive element composed of the combination of the electrode and the mountain pressure sensitive layer is increased. As a result, the resistance levels of the pressure sensitive element and the thin film transistor are matched.
Furthermore, the change in the resistance value of the mountain-shaped pressure-sensitive layer in the initial stage when a low pressure is generated (that is, the change in the detected current value) is such that the area of the initial effective area exceeds 50% of the area of the initial contact area. Compared to it, it becomes moderate. This is because the contact area between the common electrode and the mountain-shaped pressure sensitive layer continues to be small in the low pressure region. As a result, the detection accuracy of the low pressure is increased.
The area of the initial effective area may be 0 to 40% of the area of the initial contact area.
The area of the initial effective area may be 0 to 30% of the area of the initial contact area.
The area of the initial effective region is preferably 0% of the area of the initial contact region. This is because, in addition to the above principle, the shortest distance between the contact region and the adjustment electrode is longer than the film thickness of the mountain-shaped pressure-sensitive layer on the adjustment electrode. Therefore, the effect of controlling the resistance value is increased.

The adjustment electrode may not be formed at a position corresponding to the apex of the mountain-shaped pressure sensitive layer.
In this pressure sensor, the detection current can be made relatively small by keeping the resistance high in the low pressure region.

The adjustment electrode may be arranged at a position shifted in one direction from the apex of the mountain-shaped pressure sensitive layer.
In this pressure sensor, since the adjustment electrode can be formed in a wide shape, conduction with the thin film transistor is further ensured.

The pressure sensor may further include an insulating layer. The insulating layer is formed on a part of the electrode to insulate part thereof, and a portion exposed to the mountain-shaped pressure sensitive layer of the electrode is configured as an adjustment electrode.
In this pressure sensor, since the electrode can be formed wide as much as the area of the portion not exposed to the mountain-shaped pressure sensitive layer, conduction with the thin film transistor becomes more reliable.

Also, if the adjustment electrode does not exist under the initial contact position with the common electrode of the mountain pressure-sensitive layer, the resistance value becomes high and current does not flow easily. The pressure-sensitive element made of functions as a spacer. That is, it is not necessary to provide a dedicated spacer, and the density of the pressure sensitive elements can be increased, and as a result, the resolution of the pressure sensor is increased.

The pressure sensor may further include a temperature sensing element formed side by side on the plurality of adjustment electrodes.
In this pressure sensor, since the temperature sensitive element is incorporated in the pressure sensor, the temperature can be detected together with the pressure.

The temperature-sensitive element may function as a spacer by being closer to the common electrode than the plurality of mountain-shaped pressure-sensitive layers.
In this pressure sensor, the use of the temperature sensitive element as a spacer eliminates the need to provide a dedicated spacer.

The pressure sensor may further include a pressure detection unit, a temperature detection unit, and a pressure correction unit.
The pressure detection unit may detect a pressure value based on signals from a plurality of adjustment electrodes and a plurality of mountain-shaped pressure sensitive layers.
The temperature detection unit may detect the temperature value based on a signal from the temperature sensitive element.
The pressure correction unit may correct the pressure value based on the temperature value from the temperature detection unit.
In this pressure sensor, an accurate pressure value can be obtained by correcting the temperature.

In the pressure sensor according to the present invention, the pressure measurement range that can be accurately measured is widened.

1 is a schematic cross-sectional view of a pressure sensor according to a first embodiment of the present invention. The partial schematic sectional drawing of a pressure sensor. The schematic plan view of the lower electrode member of a pressure sensor. The schematic plan view of an adjustment electrode and a mountain-shaped pressure-sensitive layer. The equivalent circuit diagram of a pressure sensor. The schematic sectional drawing of a pressure sensor in the state where the pressure acted. The typical top view which shows the relationship between an adjustment electrode and a contact area. The schematic sectional drawing of a pressure sensor in the state where the pressure acted. The typical top view which shows the relationship between an adjustment electrode and a contact area. The schematic sectional drawing of a pressure sensor in the state where the pressure acted. The typical top view which shows the relationship between an adjustment electrode and a contact area. The graph which shows the relationship between the pressure of a pressure sensor, and a detection electric current. A typical sectional view showing a manufacturing method of a pressure sensor. A typical sectional view showing a manufacturing method of a pressure sensor. A typical sectional view showing a manufacturing method of a pressure sensor. A typical sectional view showing a manufacturing method of a pressure sensor. A typical sectional view showing a manufacturing method of a pressure sensor. A typical sectional view showing a manufacturing method of a pressure sensor. A typical sectional view showing a manufacturing method of a pressure sensor. A typical sectional view showing a manufacturing method of a pressure sensor. A typical sectional view showing a manufacturing method of a pressure sensor. A typical sectional view showing a manufacturing method of a pressure sensor. The typical top view which shows the modification of the planar layout of a mountain-shaped pressure sensitive layer and an adjustment electrode. The typical top view which shows the modification of the planar layout of a mountain-shaped pressure sensitive layer and an adjustment electrode. The typical top view which shows the modification of the planar layout of a mountain-shaped pressure sensitive layer and an adjustment electrode. The partial schematic sectional drawing of the pressure sensor in 2nd Embodiment. The schematic sectional drawing of a pressure sensor in the state where the pressure acted. The typical top view which shows the relationship between an adjustment electrode and a contact area. The schematic sectional drawing of a pressure sensor in the state where the pressure acted. The typical top view which shows the relationship between an adjustment electrode and a contact area. The schematic sectional drawing of a pressure sensor in the state where the pressure acted. The typical top view which shows the relationship between an adjustment electrode and a contact area. The partial schematic sectional drawing of the pressure sensor of 3rd Embodiment. The block diagram which shows the detection control structure of a pressure sensor. The graph which shows the relationship of the resistance value with respect to temperature. The partial schematic sectional drawing of the pressure sensor of the 1st modification of 3rd Embodiment. The fragmentary schematic sectional drawing of the pressure sensor of the 2nd modification of 3rd Embodiment. The partial schematic sectional drawing of the pressure sensor of the 3rd modification of 3rd Embodiment.

1. First Embodiment (1) Basic Configuration of Pressure Sensor A pressure sensor 1 according to a first embodiment will be described with reference to FIGS. FIG. 1 is a schematic cross-sectional view of a pressure sensor according to a first embodiment of the present invention. FIG. 2 is a partial schematic cross-sectional view of the pressure sensor. FIG. 3 is a schematic plan view of the lower electrode member of the pressure sensor. FIG. 4 is a schematic plan view of the adjustment electrode and the mountain-shaped pressure sensitive layer. FIG. 5 is an equivalent circuit diagram of the pressure sensor.

The pressure sensor 1 is a device that detects a pressing position and a pressing force when a pressing force is applied. For example, the pressure sensor 1 is employed in a touch panel of a smartphone, a tablet PC, or a notebook PC.
The pressure sensor 1 has an upper electrode member 3. The upper electrode member 3 is a planar member on which a pressing force acts. The upper electrode member 3 has an insulating film 7 and a common electrode 9 formed on the entire lower surface thereof, that is, spread over one surface or patterned.

The pressure sensor 1 has a lower electrode member 5. The lower electrode member 5 is a planar member disposed below the upper electrode member 3. The lower electrode member 5 includes, for example, a rectangular insulating film 15 and a plurality of adjustment electrodes 31 formed on the upper surface via other members (described later). The adjustment electrode is also referred to as an individual electrode or a pixel electrode.
The lower electrode member 5 has a plurality of mountain-shaped pressure sensitive layers 33. The plurality of mountain-shaped pressure sensitive layers 33 are respectively formed on the common electrode 9 side of the plurality of adjustment electrodes 31.

The “mountain shape” has an apex and a peripheral portion, and includes a dome shape, a cone shape, a frustum shape, and other shapes. The mountain-shaped planar shape includes a circle, a square, and other shapes.
Due to the mountain shape, the contact area between the common electrode 9 and the mountain pressure-sensitive layer 33 increases according to the pressure. In addition, the thickness of the mountain-shaped pressure-sensitive layer 33 is reduced toward the outer periphery, and the resistance value is decreased. In other words, when the pressure is low, only the apex (center in the radial direction) of the mountain-shaped pressure sensitive layer 33 is in contact with the common electrode 9, and the contact area is small. When the pressure is high, the common electrode 9 is in contact with the mountain-shaped middle (radially intermediate portion) or ridge (outer circumferential portion) of the mountain-shaped pressure-sensitive layer 33, and the contact area is large.
As an example, the height H of the mountain-shaped pressure sensitive layer 33 is 5 to 100 μm in a wide range and 10 to 30 μm in a narrow range. The diameter L of the mountain-shaped pressure-sensitive layer 33 is 0.1 to 1.0 mm in a wide range, and 0.3 to 0.6 mm in a narrow range.

As shown in FIGS. 2 and 4, the mountain-shaped pressure sensitive layer 33 covers the entire adjustment electrode 31. The adjustment electrode 31 has a circular shape in plan view, and is formed at a position shifted from the position of the apex T (center) of the mountain-shaped pressure-sensitive layer 33. That is, the adjustment electrode is not formed at a position corresponding to the apex (center portion) of the mountain-shaped pressure sensitive layer 33.
The adjustment electrode 31 has a circular shape in plan view, but may have another shape such as a square or a triangle. The adjustment electrode 31 has a small area with respect to the mountain-shaped pressure-sensitive layer 33, but has a certain spread. For this reason, the adjustment electrode can be formed in a wide shape, so that conduction with the TFT 30 is further ensured.

The upper electrode member 3 and the lower electrode member 5 are bonded to each other by a frame spacer 13 at the peripheral portion as shown in FIG. The frame spacer 13 is formed in a frame shape, and is made of, for example, an adhesive or a double-sided tape.

As shown in FIG. 3, the pressure-sensitive elements including the plurality of adjustment electrodes 31 and the mountain-shaped pressure-sensitive layers 33 are arranged so as to be spread over the entire plane. The matrix form means a state in which the matrix is two-dimensionally arranged. As shown in FIGS. 1 and 2, the frame spacer 13 ensures a gap between the common electrode 9 and the mountain-shaped pressure sensitive layer 33 even in the initial state. Thereby, zero pressure can be measured reliably. Furthermore, the initial resistance value change can be reliably measured since it starts from zero contact area. However, the common electrode 9 and the mountain-shaped pressure-sensitive layer 33 may be in contact with each other in the initial state.

When the region of the common electrode 9 is pushed down toward the mountain-shaped pressure sensitive layer 33, the common electrode 9 and the adjustment electrode 31 positioned in the pushed-down region are electrically connected. The depression may be performed with, for example, a finger, a stylus pen, a stick, a palm, or a sole. The electrode pitch is, for example, 0.3 to 1.5 mm.
The lower electrode member 5 includes a plurality of thin film transistors 30 (hereinafter referred to as “TFT 30”). Each TFT 30 is provided corresponding to each of the adjustment electrodes 31 and functions as an electrode for current value detection.

(2) Relationship between TFT and Adjustment Electrode As shown in FIGS. 1 and 2, the TFT 30 includes a source electrode 17, a drain electrode 19, and a gate electrode 21. The TFT 30 is a top gate type. The material which comprises a gate electrode, a source electrode, and a drain electrode is not specifically limited. The TFT may be a bottom gate type.

The source electrode 17 and the drain electrode 19 are formed on the upper surface of the insulating film 15. The TFT 30 has a semiconductor layer 23 formed between the source electrode 17 and the drain electrode 19. As a material for forming such a semiconductor layer, a known material such as silicon, an oxide semiconductor, or an organic semiconductor can be used.
The TFT 30 has a first insulating film 25 formed so as to cover the source electrode 17, the drain electrode 19 and the semiconductor layer 23.

The drain electrode 19 is connected to the adjustment electrode 31 as described later. The gate electrode 21 is formed above the semiconductor layer 23 on the upper surface of the first insulating film 25.
The TFT 30 has a second insulating film 27 that is formed on the upper surface of the first insulating film 25 and covers the gate electrode 21.
The plurality of adjustment electrodes 31 are formed on the upper surface of the second insulating film 27. The adjustment electrode 31 is connected to the TFT 30 via a conductive portion 29 formed in a through hole that penetrates the first insulating film 25 and the second insulating film 27.

The operation principle of the pressure sensor 1 will be described with reference to FIG. When a voltage is applied to the drain electrode 19 of the TFT 30 to which the gate voltage is input, a drain current corresponding to the resistance of the mountain-shaped pressure sensitive layer 33 flows. Since the resistance decreases as the pressure applied to the mountain-shaped pressure sensitive layer 33 increases, an increase in drain current is detected. By sweeping the TFT 30 on the pressure sensor 1 and applying a gate voltage and measuring the drain current, the pressure distribution on the sheet surface can be observed.
The pressure sensor 1 has a circuit part (not shown). The circuit unit controls the drain electrode 19, the source electrode 17, and the common electrode 9. For example, according to the power supply voltage for applying a predetermined voltage to the common electrode 9 and the source electrode 17 and the current value between the source and drain. And a current detection circuit that generates a signal and outputs it to an external signal processing device. The external signal processing device detects the pressing position and the pressing force based on the signal sent from the circuit unit.

(3) Pressing Operation and Pressure Measuring Operation The pressing operation and pressure measuring operation will be described with reference to FIGS. 6, 8 and 10 are schematic cross-sectional views of the pressure sensor in a state where pressure is applied. 7, 9 and 11 are schematic plan views showing the relationship between the adjustment electrode and the contact area. In FIGS. 6 to 11, the shape of each region is square for convenience of understanding.
When pressure is applied, the resistance of the mountain-shaped pressure sensitive layer 33 decreases. The potential difference between the source and the drain when a constant voltage is applied by the voltage power supply depends on the resistance value of the mountain-shaped pressure sensitive layer 33 connected in series with the drain electrode 19. As a result, the potential difference between the source and the drain increases, and the amount of current flowing increases. Therefore, if the pressing force and current amount to be applied to the mountain-shaped pressure-sensitive layer 33 are acquired in advance, the signal processing device (not shown) reads the change in the signal according to the current amount, so that the pressure sensor 1 The amount of pressure applied (pressing force) can be detected.

(3-1) Low Pressure As shown in FIG. 6, a small force F1 acts on the upper electrode member 3, and therefore the common electrode 9 is only around the apex T (center) of the mountain-shaped pressure sensitive layer 33. Contact.
As shown in FIGS. 6 and 7, the contact area 36 A where the common electrode 9 is in contact with the mountain-shaped pressure-sensitive layer 33 is small. Therefore, the contact area 36 A does not overlap the adjustment electrode 31 in plan view. A portion where the contact region 36A and the adjustment electrode 31 overlap is a region where current mainly flows. In the case of FIGS. 6 and 7, the area of the region is zero. As a result, the detection current is low.

In other words, the above description shows the state when the initial contact pressure acts on the pressure sensor 1. In this case, when the pressing force on the common electrode 9 is the initial contact pressure, the contact region where the common electrode 9 and each mountain-shaped pressure-sensitive layer 33 are in contact is defined as the initial contact region, and the adjustment electrode 31 that overlaps the initial contact region in plan view. When the region is an initial effective region, the area of the initial effective region is 0% of the area of the initial contact region. This is because the initial effective area is zero. In other words, the adjustment electrode 31 exists only outside the initial contact area. The initial contact pressure is a pressure applied to the common electrode 9 immediately after the pressing force acts on the common electrode 9 and the common electrode 9 contacts one or a plurality of mountain-shaped pressure sensitive layers 33 corresponding to the pressing portion. is there.
When the initial effective area exceeds zero, it is preferable that the ratio is small. For example, the ratio is set to 10% or less, 20% or less, 30% or less, 40% or less, 50% or less, or 60% or less. However, in order to sufficiently obtain the effects of the present embodiment, it is preferably 50% or less. That is, when the area of the initial effective region is 0 to 50% of the area of the initial contact region, the adjustment electrode 31 does not correspond to the electrode contact portion of the mountain-shaped pressure sensitive layer 33 at all or the corresponding ratio is below a predetermined value. The resistance value of the pressure sensitive element composed of the combination of the adjustment electrode 31 and the mountain pressure sensitive layer 33 is increased. As a result, the resistance levels of the pressure sensitive element and the TFT 30 are matched.
The area of the initial effective region is preferably 0% of the area of the initial contact region. This is because, in addition to the above principle, the shortest distance between the contact region and the adjustment electrode 31 is longer than the film thickness of the mountain-shaped pressure-sensitive layer 33 on the adjustment electrode 31. Therefore, the effect of controlling the resistance value is increased.
In any case, the adjustment electrode 31 further includes a pressure measurement region outside the initial contact region.

Further, when the initial effective area exceeds zero, the area of the contact region where the pressing force becomes greater than the initial contact pressure later, the area of the portion facing the adjustment electrode 31 (maximum in the case of high pressure described later) The effective area is preferably larger than the initial effective area, for example, 2 times or more, 3 times or more, and 4 times or more. However, in order to sufficiently obtain the effects of the present embodiment, it is preferably twice or more.
Furthermore, when the initial effective area is zero, the resistance value can be controlled by the conduction distance from the initial contact position of the mountain-shaped pressure-sensitive layer 33 with the common electrode 9 to the adjustment electrode 31 (the shortest distance in the mountain-shaped pressure-sensitive layer). . Specifically, the conduction distance in the present embodiment is preferably at least twice the conduction distance of the conventional example in which the electrode is directly below the initial contact position, and more preferably 5 to 10 times.
In the above example, the initial contact pressure is 1 N, and the initial contact area is the area at that time. The initial contact pressure can be appropriately selected from the range of 0.8 to 1.2N.
The initial contact area is defined as an area having a height of 70% or more (for example, 14 um) of the pressure-sensitive layer height (for example, 20 um), more preferably an area having a height of 80% or more (for example, 16 um). It is good.

(3-2) Medium Pressure As shown in FIG. 8, a medium force F2 is applied to the upper electrode member 3, so that the common electrode 9 further moves from the vicinity of the apex T of the mountain-shaped pressure sensitive layer 33. It also contacts the outer peripheral part. That is, the contact surface between the common electrode 9 and the mountain pressure-sensitive layer 33 is widened.
As shown in FIGS. 8 and 9, the contact region 36 B where the common electrode 9 is in contact with the mountain-shaped pressure-sensitive layer 33 is medium. Therefore, the contact region 36 B overlaps a part of the adjustment electrode 31 in a plan view. As a result, in the case of FIGS. 8 and 9, the area of the overlap region is medium, that is, the detection current is medium.

(3-3) In the case of high pressure In FIG. 10, a large force F3 is applied to the upper electrode member 3, and therefore the common electrode 9 is in contact with the outer peripheral side portion of the mountain-shaped pressure sensitive layer 33. . That is, the contact surface between the common electrode 9 and the mountain-shaped pressure sensitive layer 33 is further expanded.
As shown in FIGS. 10 and 11, the contact area 36 C where the common electrode 9 is in contact with the mountain-shaped pressure-sensitive layer 33 is large. Therefore, the contact region 36 C overlaps the entire adjustment electrode 31 in plan view. As a result, in the case of FIG. 10 and FIG. 11, the area of the overlapping region is large and the detection current is large.

It is preferable that the insulating film 7 and the common electrode 9 have elasticity. Thereby, the followability of the common electrode 9 to the mountain-shaped pressure-sensitive layer 33 is improved when pressure is applied. In other words, when the pressure is high, the common electrode 9 is likely to be in close contact with the outer peripheral side of the mountain-shaped pressure sensitive layer 33 (the thin portion of the mountain-shaped pressure sensitive layer 33). As a result, the difference in contact resistance of the mountain-shaped pressure sensitive layer 33 is increased, that is, the measurement range is increased.
In addition, since the insulating film 7 and the common electrode 9 have elasticity, the performance of restoring the insulating film 7 and the common electrode 9 when the pressure is removed is improved. As a result, reproducibility of repeated measurement is improved.

In general, when pressure is applied to the insulating film 7 and the common electrode 9, a large area of bending occurs, but a load acts on a plurality of small area pressure-sensitive layers and electrodes, and in that case There was a risk that the common electrode 9 would crack or deform. However, in this embodiment, the insulating film 7 and the common electrode 9 have elasticity, so that the common electrode 9 is unlikely to crack or deform in the mountain-shaped pressure sensitive layer 33. As a result, the reliability of the pressure sensor 1 is improved.
When the soft and thin base material is brought to the upper side as described above, the contact area does not change any more when the common electrode 9 is completely in contact with the top of the mountain-shaped pressure-sensitive layer 33. Although the measurement range is narrow, the pressure resolution is increased because the difference in contact area is large. In addition, the thickness and hardness of the substrate are appropriately selected according to the range to be measured.

(3-4) Comparison of Embodiment and Comparative Example With reference to FIG. 12, the rate of change in resistance with respect to pressure will be described for the present embodiment, Comparative Example 1, Comparative Example 2, and Comparative Example 3. FIG. 12 is a graph showing the relationship between the pressure of the pressure sensor and the detected current.
Comparative Example 1 is a conventional example using a flat pressure-sensitive layer. The change rate of the current value is small in the entire region from low pressure to high pressure. That is, the sensitivity is low. Further, when a high pressure is applied, the rate of change of resistance is close to 0%, that is, an accurate pressure cannot be measured.

Comparative Example 2 is not an active matrix system, and a solid electrode is provided to face the common electrode. Further, when a high pressure is applied, the rate of change of resistance is close to 0%, that is, an accurate pressure cannot be measured.
Comparative Example 3 is an example in which the electrodes are entirely formed from the top of the mountain-shaped pressure sensitive layer to the periphery of the mountain-shaped pressure sensitive layer. In this case, a high rate of change is obtained over the entire region, that is, high sensitivity.

This embodiment has a rate of change that achieves sufficient sensitivity in the low-pressure region, although it is lower than that of Comparative Example 3. The reason will be described below.
The adjustment electrode 31 has a contact surface between the common electrode 9 and the mountain-shaped pressure-sensitive layer 33 as a result of a pressing force acting on the common electrode 9 toward the mountain-shaped pressure-sensitive layer 33. It spreads outward from the vertex T. At this time, the area of the portion sandwiched between the contact region and the adjustment electrode 31 (the area of the contact regions 36A to 36C described above) gradually increases. From the above, as the pressure increases, the resistance value of the mountain-shaped pressure-sensitive layer 33 decreases, and as a result, the detected current value increases. In particular, the sensitivity is sufficiently high even in a high pressure range (for example, a test force of 50 N or more), and the pressure can be accurately measured. As a result, the measurement range of pressure is widened.

Furthermore, since the pressure measurement region of the adjustment electrode 31 is located at a position deviated from the apex T (center) of the mountain-shaped pressure sensitive layer 33, the following effects can be obtained. That is, the change in the resistance value of the mountain-shaped pressure sensitive layer 33 in the initial stage when a low pressure is generated (that is, the change in the detected current value) is gentler than that in which the electrode is at the apex T of the mountain-shaped pressure sensitive layer. Become. This is because the contact area between the common electrode 9 and the adjustment electrode 31 continues to be small in the low pressure region. As a result, the detection accuracy of the low pressure is increased.
In the embodiment described above, the adjustment electrode 31 is not formed at a position corresponding to the apex T of the mountain-shaped pressure sensitive layer 33. Therefore, the detection current can be made relatively small by keeping the resistance high in the low pressure region.

(4) Materials As the insulating film 7 and the insulating film 15, engineering plastics such as polycarbonate, polyamide, or polyether ketone, or resin films such as acrylic, polyethylene terephthalate, or polybutylene terephthalate are used. Can be used.
In the case where the insulating film 7 requires stretchability, for example, a urethane film, silicon, or rubber is used. The insulating film 7 and the insulating film 15 are preferably made of a material having heat resistance because the electrodes are printed and dried.

As the common electrode 9 and the adjustment electrode 31, a metal oxide film such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, or indium tin oxide (ITO), or a composite mainly composed of these metal oxides. A film or a metal film such as gold, silver, copper, tin, nickel, aluminum, or palladium is used. When the common electrode 9 requires stretchability, for example, stretchable Ag paste is used.
The mountain pressure-sensitive layer 33 is made of, for example, pressure-sensitive ink. Pressure-sensitive ink is a material that enables pressure detection by changing the contact resistance with an opposing electrode in accordance with an external force. The pressure sensitive ink layer can be arranged by coating. As a method for applying the pressure-sensitive ink layer, a printing method such as screen printing, offset printing, gravure printing, or flexographic printing, or application by a dispenser can be used.

(5) Manufacturing Method of Pressure Sensor A manufacturing method of the pressure sensor 1 will be described with reference to FIGS. 13 to 22 are schematic cross-sectional views showing a manufacturing method of the pressure sensor.
First, each step of the method for manufacturing the lower electrode member 5 will be described with reference to FIGS.

As shown in FIG. 13, an electrode material 37 is formed on one surface of the insulating film 15 by, for example, sputtering.
As shown in FIG. 14, the film exposure part 39 is formed by removing a part of electrode material 37, for example by the photolithographic method. Thereby, the source electrode 17 and the drain electrode 19 are formed. In addition, the formation method of the source electrode 17 and the drain electrode 19 is not specifically limited.

As shown in FIG. 15, the semiconductor layer 23 is formed in the film exposed portion 39. The method for forming the semiconductor layer 23 is a known technique.
As shown in FIG. 16, a first insulating film 25 is formed so as to cover the surface on which the source electrode 17, the drain electrode 19 and the semiconductor layer 23 are formed.
As shown in FIG. 17, the gate electrode 21 is formed above the semiconductor layer 23 on the upper surface of the first insulating film 25. The formation method of the gate electrode 21 is a known technique.

As shown in FIG. 18, the second insulating film 27 is formed so as to cover the entire first insulating film 25 on which the gate electrode 21 is formed.
As shown in FIG. 19, a through hole reaching the drain electrode 19 is formed in the first insulating film 25 and the second insulating film 27 by a laser, and a conductive material 29 is filled therein to form a conductive portion 29.

As shown in FIG. 20, the adjustment electrode 31 is formed by a printing method and connected to the TFT 30 via the conductive portion 29.
As shown in FIG. 21, a mountain-shaped pressure-sensitive layer 33 is formed on the adjustment electrode 31 by a printing method.

Next, the manufacture of the upper electrode member 3 will be described with reference to FIG.
As shown in FIG. 22, the common electrode 9 is formed on one surface of the insulating film 7 by a printing method.
Note that the material of the common electrode 9 may be formed on one surface of the insulating film 7 by sputtering, for example, and then the common electrode 9 may be formed by photolithography.
Finally, the upper electrode member 3 and the lower electrode member 5 are bonded together via a frame-shaped frame spacer 13 (FIG. 2) made of an adhesive, thereby completing the pressure sensor 1.

(6) Modification Example of Planar Position of Adjustment Electrode In the first embodiment, the adjustment electrode 31 is a circular shape at a position shifted in one direction from the apex T of the mountain-shaped pressure-sensitive layer 33. As described above, since the area of the initial effective region may be 50% or less of the area of the initial contact region, the planar position of the adjustment electrode is not particularly limited.
Hereinafter, modified examples that satisfy the above conditions will be described.

In the modification shown in FIG. 23, the adjustment electrode 31 A has a circular belt shape concentric with the mountain-shaped pressure-sensitive layer 33. That is, the adjustment electrode 31 A does not have an electrode portion corresponding to the apex T of the mountain-shaped pressure sensitive layer 33.
In the modification shown in FIG. 24, the adjustment electrode 31 B has a linear shape shifted to one side from the center of the mountain-shaped pressure-sensitive layer 33. That is, the adjustment electrode 31 A does not have an electrode portion corresponding to the apex T of the mountain-shaped pressure sensitive layer 33.

In the modification shown in FIG. 25, the adjustment electrode 31 C has an arc shape along the outer periphery of the mountain-shaped pressure sensitive layer 33. That is, the adjustment electrode 31 C does not have an electrode portion corresponding to the apex T of the mountain-shaped pressure sensitive layer 33.
As a further modification, in the embodiment and the modification, the adjustment electrode may have a portion disposed at a position corresponding to the vicinity of the apex of the mountain-shaped pressure-sensitive layer in addition to the pressure measurement region described above. .

2. Second Embodiment In the above-described embodiment, the pressure measurement region of the adjustment electrode is realized by forming the electrode at a position shifted from the vicinity of the apex of the mountain-shaped pressure sensitive layer. However, as described above, since the area of the initial effective region may be 50% or less of the area of the initial contact region, the adjustment electrode may be realized by another structure.
A pressure sensor 1A as such an embodiment will be described with reference to FIG. FIG. 26 is a schematic plan view illustrating a modification of the planar layout of the pressure-sensitive layer and the adjustment electrode in the second embodiment.

(1) Points different from the first embodiment The basic structure is the same as the pressure sensor 1 of the first embodiment. Therefore, the following description will focus on the different points.

Unlike the embodiment, the electrode 31D is formed in substantially the same shape corresponding to the mountain-shaped pressure-sensitive layer 33D. That is, the electrode 31D is entirely formed from the apex T to the periphery of the mountain-shaped pressure sensitive layer 33D.
An insulating layer 51 is formed on the upper surface of the electrode 31D. The insulating layer 51 is formed on the periphery of the apex T (center) of the electrode 31D to insulate the portion, and the adjustment electrode 31a that is the annular peripheral portion of the electrode 31D is exposed to the mountain-shaped pressure-sensitive layer 33D. I am letting.

(2) Pressing Operation and Pressure Measuring Operation The pressing operation and the pressure measuring operation will be described with reference to FIGS. 27, 29 and 31 are schematic cross-sectional views of the pressure sensor in a state where pressure is applied. 28, 30 and 32 are schematic plan views showing the relationship between the adjustment electrode and the contact area. In FIG. 27 to FIG. 32, for easy understanding, the shape of each region is square for convenience.

(2-1) Low Pressure As shown in FIG. 27, a small force F1 acts on the upper electrode member 3, and therefore the common electrode 9 is only around the apex T (center) of the mountain-shaped pressure sensitive layer 33D. Contact.
As shown in FIGS. 27 and 28, the contact region 53A where the common electrode 9 is in contact with the mountain-shaped pressure sensitive layer 33D is small. Therefore, the contact region 53A does not overlap the adjustment electrode 31a in plan view. A portion where the contact region and the adjustment electrode 31a overlap is a region where current mainly flows. In the case of FIGS. 27 and 28, the area of the region is zero as described above, and thus the detection current is low.

In other words, the above description shows the state when the initial contact pressure acts on the pressure sensor 1. In this case, when the pressing force on the common electrode 9 is the initial contact pressure, the contact region where the common electrode 9 and each mountain-shaped pressure-sensitive layer 33 are in contact is defined as the initial contact region, and the adjustment electrode 31a overlapping the initial contact region in plan view When the region is an initial effective region, the area of the initial effective region is 0% of the area of the initial contact region. This is because the initial effective area is zero.
When the initial effective area exceeds zero, it is preferable that the ratio is small. For example, the ratio is set to 10% or less, 20% or less, 30% or less, 40% or less, 50% or less, or 60% or less. However, in order to sufficiently obtain the effects of the present embodiment, it is preferably 50% or less. That is, when the area of the initial effective region is 0 to 50% of the area of the initial contact region, the adjustment electrode 31a does not correspond to the electrode contact portion of the mountain-shaped pressure sensitive layer 33 at all, or the corresponding ratio is below a predetermined value. The resistance value of the pressure sensitive element composed of the combination of the adjustment electrode 31a and the mountain pressure sensitive layer 33 is increased. As a result, the resistance levels of the pressure sensitive element and the TFT 30 are matched.
The area of the initial effective region is preferably 0% of the area of the initial contact region. The reason is that, in addition to the above principle, the shortest distance between the contact region and the adjustment electrode 31 a is longer than the film thickness of the mountain-shaped pressure sensitive layer 33 on the adjustment electrode 31. Therefore, the effect of controlling the resistance value is increased.
In any case, the adjustment electrode 31a further includes a pressure measurement region outside the initial contact region.
Furthermore, when the effective area is the area of the contact area where the adjustment electrode 31a overlaps (maximum in the case of high pressure described later), the effective area is preferably larger than the initial effective area. It is set to more than double and four times. However, in order to sufficiently obtain the effects of the present embodiment, it is preferably twice or more.

(2-2) Medium Pressure As shown in FIG. 29, a medium force F2 is applied to the upper electrode member 3, so that the common electrode 9 has an apex T (center) of the mountain-shaped pressure sensitive layer 33D. It also contacts the outer peripheral part from the periphery. That is, the contact surface between the common electrode 9 and the mountain-shaped pressure sensitive layer 33D is widened.
As shown in FIGS. 29 and 30, the contact region 53B where the common electrode 9 is in contact with the mountain-shaped pressure-sensitive layer 33D is intermediate. Therefore, the contact region 53B further extends from the insulating layer 51 in plan view, and thus overlaps a part of the adjustment electrode 31a. As a result, in the case of FIG. 29 and FIG. 30, the area of the overlapping region is medium, so that the detection current is medium.

(2-3) In the case of high pressure In FIG. 31, a large force F3 is applied to the upper electrode member 3, and therefore the common electrode 9 is in contact with the portion on the outer peripheral side of the mountain-shaped pressure-sensitive layer 33D. . That is, the contact surface between the common electrode 9 and the mountain-shaped pressure sensitive layer 33D is further expanded.
As shown in FIGS. 31 and 32, the contact region 53C where the common electrode 9 is in contact with the mountain-shaped pressure-sensitive layer 33 is large. Therefore, the contact region 53C further extends from the insulating layer 51 in plan view, and therefore overlaps most of the adjustment electrode 31a. As a result, in the case of FIGS. 31 and 32, the area of the overlapping region is large. As a result, the detection current is increased.

In this pressure sensor, since the electrode 31D can be formed wide as much as the area not exposed to the mountain-shaped pressure-sensitive layer 33, conduction with the TFT 30 becomes more reliable. Further, if the adjustment electrode 31a does not exist below the initial contact position of the mountain-shaped pressure-sensitive layer 33 with the common electrode 9, the resistance value becomes high and current does not flow easily. A pressure sensitive element composed of the pressure sensitive layer 33D functions as a spacer. That is, it is not necessary to provide a dedicated spacer, and the density of the pressure sensitive elements can be increased. As a result, the resolution of the pressure sensor 1A is increased.

(3) First Modification In the second embodiment, the position where the insulating layer is formed is around the apex T (center) of the electrode. As described above, the adjustment electrode has an initial effective area in the initial contact. Since the area may be 50% or less of the area, the formation position of the insulating layer is not particularly limited.
For example, the exposed portion of the electrode (that is, the adjustment electrode) may be a linear portion corresponding to one side or a plurality of sides around the electrode. Further, the exposed portion of the electrode (that is, the adjustment electrode) may be a portion having a predetermined spread at one or a plurality of locations around the electrode.
(4) Second Modification In the second embodiment, the insulating layer is completely covered with the mountain-shaped pressure-sensitive layer. However, as a modification, the insulating layer may protrude from the mountain-shaped pressure-sensitive layer.

3. Third Embodiment In the first embodiment and the second embodiment, only the pressure sensitive element for measuring pressure is arranged in the pressure sensor, but the measuring element for measuring other physical phenomena is also arranged in the pressure sensor. May be.
The pressure sensors described in the first and second embodiments are excellent in that an output (change in resistance value) corresponding to the applied pressure is obtained. However, since the electrical characteristic value such as the electrical resistance value changes greatly depending on the temperature and humidity, for example, the electrical resistance value changes when the temperature changes, and the detected pressure value even if the pressure is the same. May be different.

An embodiment capable of solving the above problem will be described with reference to FIG. FIG. 33 is a partial schematic cross-sectional view of the pressure sensor of the third embodiment.
The basic structure of the pressure sensor 1B is the same as that of the first embodiment.

(1) Temperature Sensitive Element As shown in FIG. 33, the pressure sensor 1B has a plurality of temperature sensitive elements 71. The temperature sensing element 71 is formed side by side with the plurality of adjustment electrodes 31. Thus, since the temperature sensitive element 71 is incorporated in the pressure sensor 1B, the temperature of the object can be detected together with the pressure from the object.

The temperature sensing element 71 functions as a spacer by being closer to the common electrode 9 than the plurality of mountain-shaped pressure sensitive layers 33. The temperature sensing element 71 as a spacer ensures a gap between the common electrode 9 and the mountain-shaped pressure-sensitive layer 33 when no pressure is applied, so that the pressure acting on the mountain-shaped pressure-sensitive layer 33 can be reduced to zero. . By using the temperature sensitive element 71 as a spacer in this way, it is not necessary to provide a dedicated spacer.

The structure and operation of the temperature sensitive element 71 are known techniques. Hereinafter, the structure of the temperature sensing element 71 will be briefly described.
The temperature sensitive element 71 has a first electrode 73A and a second electrode 73B. The first electrode 73 A and the second electrode 73 B are formed on the upper surface of the second insulating film 27.
The temperature sensing element 71 has a temperature sensing layer 75. The temperature sensitive layer 75 extends between the first electrode 73A and the second electrode 73B and further covers the upper surfaces of both. The temperature sensitive layer 75 is made of a material whose resistance value changes depending on the temperature.
The temperature sensitive element 71 has an insulating layer 77. The insulating layer 77 covers the temperature sensitive layer 75. The surface of the insulating layer 77 is close to or in contact with the lower surface of the common electrode 9.

(2) Pressure Detection Control Configuration A control configuration and control operation for detecting pressure and temperature will be described with reference to FIGS. 34 and 35. FIG. FIG. 34 is a block diagram showing a detection control configuration of the pressure sensor. FIG. 35 is a graph showing the relationship of the resistance value with respect to temperature.
As shown in FIG. 34, the pressure sensor 1B includes a temperature detection unit 83, a pressure detection unit 85, and a pressure correction unit 87.

The temperature detector 83 detects a temperature value based on a signal from the temperature sensing element 71. Specifically, the temperature detection unit 83 converts an analog signal into a digital signal and outputs it to the pressure correction unit 87 as temperature value information.
The pressure detection unit 85 detects a pressure value based on signals from the pressure-sensitive element 35 including a plurality of adjustment electrodes and a plurality of mountain-shaped pressure-sensitive layers. Specifically, the pressure detection unit 85 converts an analog signal into a digital signal and outputs it as pressure value information to the pressure correction unit 87.

The pressure correction unit 87 corrects the pressure value based on the temperature value. Specifically, the pressure sensor 1 has a storage unit in which the temperature characteristics (for example, information of the graph shown in FIG. 35) of each pressure-sensitive element 35 are stored, and the pressure correction unit 87 is stored in the storage unit. The pressure value obtained from the pressure detector 85 is corrected based on the stored temperature characteristic of the pressure sensitive element 35 (that is, the change in electrical resistance due to temperature is removed by calculation). By correcting the pressure value, an accurate pressure distribution applied to the pressure sensor 1B can be obtained. The corrected pressure value is output to the outside or stored in the storage unit.

(3) First Modification In the third embodiment, the pressure sensitive element 35A may be the same as that of the second embodiment.
Such a modification is shown in FIG. FIG. 36 is a partial schematic cross-sectional view of a pressure sensor according to a first modification of the third embodiment.
As shown in FIG. 36, the temperature sensing element 71 is formed higher than the pressure sensing element 35A, and realizes a function as a spacer.

(4) Second Modification In the third embodiment, the temperature sensitive element has an insulating layer. However, since the common electrode and the temperature sensitive layer may be insulated, the insulating layer may be omitted.
Such a modification is shown in FIG. FIG. 37 is a partial schematic cross-sectional view of a pressure sensor according to a second modification of the third embodiment.
As shown in FIG. 37, no insulating layer is formed on the temperature sensitive element 71A. Instead, the common electrode 9 has a missing portion 9a at a location corresponding to the temperature sensitive element 71A. In other words, the lower surface of the insulating film 7 has the facing portion 7a facing the temperature sensitive element 71A due to the missing portion 9a.
As a result, the common electrode 9 and the temperature sensitive element 71A do not contact each other.

(5) Third Modification By using the same material for the pressure-sensitive layer and the temperature-sensitive layer, a process that can be simultaneously formed by one printing may be realized. That is, the manufacturing process can be reduced in the manufacturing method of the pressure sensor including the pressure-sensitive layer and the temperature-sensitive layer.
In FIG. 38, the pressure sensitive layer 33 and the temperature sensitive layer 75A are formed of the same material. FIG. 38 is a partial schematic cross-sectional view of a pressure sensor according to a third modification of the third embodiment.
(6) Fourth Modification A pressure-sensitive element having a flat pressure-sensitive layer and a temperature-sensitive element may be combined. That is, the type of the pressure sensitive element is not particularly limited in the combination of the temperature sensitive element and the pressure sensitive element.

4). Other Embodiments Although a plurality of embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. In particular, a plurality of embodiments and modifications described in this specification can be arbitrarily combined as necessary.

(1) Modification Example of Planar Layout of Adjustment Electrode and Mountain Pressure Sensitive Layer In the first to third embodiments, the pressure sensitive element composed of the adjustment electrode 31 and the mountain pressure sensitive layer 33 is completely aligned in rows and columns. Arranged in a matrix shape. However, the pressure sensitive elements need only be arranged in a matrix shape in a broad sense. For example, the layout of the pressure sensitive elements may be a polygonal (for example, hexagonal, parallelogram) repetitive lattice. Furthermore, the layout of the pressure sensitive elements is not uniformly arranged, and gaps may be formed at a plurality of locations.

(2) Modification of planar shape of adjustment electrode and mountain-shaped pressure-sensitive layer In the first to third embodiments, the planar shape of the adjustment electrode 31 and the mountain-shaped pressure-sensitive layer 33 is the same, but is not particularly limited. Both shapes may be different.

(3) Modified Example of Common Electrode In the first to third embodiments, the common electrode 9 is in direct contact with the mountain-shaped pressure sensitive layer 33, but may be in contact with another layer. For example, a pressure sensitive layer may be formed on the common electrode 9.

(4) First modified example of side shape of mountain-shaped pressure-sensitive layer In the first to third embodiments, the mountain-shaped pressure-sensitive layer 33 has a dome shape and the side surface shape has a semicircular shape. Not. However, in order to obtain a desired effect, the mountain-shaped pressure-sensitive layer 33 needs to have a predetermined height or more for the purpose of making contact with the common electrode 9 in a stepwise manner. Further, in order to bring the common electrode into contact with the side surface portion on the outer peripheral side, the angled pressure-sensitive layer 33 needs to have an inclination angle of a predetermined value or less.

As described above, the mountain-shaped pressure-sensitive layer 33D may have a conical shape or a truncated cone shape.
Furthermore, the mountain-shaped shape of the mountain-shaped pressure-sensitive layer may be provided only on the top of the mountain-shaped pressure-sensitive layer.

(5) Second modification of side shape of mountain-shaped pressure-sensitive layer In the first to third embodiments, the peak of the mountain-shaped pressure-sensitive layer is formed in the center in plan view. May be formed off the center. For example, the mountain-shaped pressure sensitive layer may have a convex portion including a vertex at a position other than the center.

(6) Modified example of relationship between mountain-shaped pressure-sensitive layers In the first to third embodiments, the plurality of mountain-shaped pressure-sensitive layers 33 are electrically independent from each other, but are not particularly limited. The plurality of mountain-shaped pressure sensitive layers may be in contact with each other or continuous.

(7) Modified Example of Thin Film Transistor In the first to third embodiments, a thin film transistor is associated with each individual electrode, and the current of each thin film transistor is detected. In other words, one thin film transistor is connected to one adjustment electrode.
However, a plurality of thin film transistors may correspond to one adjustment electrode, and currents of the plurality of thin film transistors may be detected. Specifically, two or more thin film transistors adjacent to one adjustment electrode are connected. As a result, the detected current value is increased, and the circuit can be made redundant.

An example in the case where a total of four 2 × 2 thin film transistors shown in FIG. 5 correspond to one adjustment electrode will be described. In that case, the gate lines G1 and G2 are short-circuited, the source lines S1 and S2 are short-circuited, and the four drain electrodes are short-circuited to be connected to one adjustment electrode through the through hole and the conductive portion.
There can be a plurality of combinations of thin film transistors, for example, 2 × 3, 3 × 2, 4 × 4, and 5 × 2. A plurality of combination patterns may exist in one pressure device.

The present invention can be widely applied to pressure sensors having a pressure-sensitive layer and a large number of thin film transistors. In particular, the pressure sensor according to the present invention is suitable for a sheet sensor having a large area other than a touch panel. Specifically, the pressure sensor according to the present invention can be applied to walking measurement technology (medical, sports, and security fields) and bed bed slip measurement technology.

1: Pressure sensor 3: Upper electrode member 5: Lower electrode member 7: Insulating film 9: Common electrode 13: Frame spacer 15: Insulating film 30: Thin film transistor 31: Adjustment electrode 31a: Peripheral part 33: Mountain type pressure sensitive layer 35 : Pressure sensitive element 51: Insulating layer

Claims

A common electrode formed on one side,
A plurality of adjusting electrodes provided in a matrix facing the common electrode;
A plurality of mountain-shaped pressure-sensitive layers respectively formed on the common electrode side of the plurality of adjustment electrodes;
A plurality of thin film transistors provided corresponding to the plurality of adjustment electrodes on the side opposite to the common electrode of the plurality of adjustment electrodes, wherein one or two or more adjacent ones are connected to one adjustment electrode,
When the pressing force against the common electrode is the initial contact pressure, a contact region where the common electrode and each mountain-shaped pressure-sensitive layer are in contact is defined as an initial contact region, and the region of the adjustment electrode that overlaps the initial contact region in plan view is the initial region. As an effective region, the area of the initial effective region is 0 to 50% of the area of the initial contact region,
The pressure sensor further includes a pressure measurement region outside the initial contact region.
The pressure sensor according to claim 1, wherein an area of the initial effective region is 0 to 40% of an area of the initial contact region.
The pressure sensor according to claim 2, wherein an area of the initial effective area is 0 to 30% of an area of the initial contact area.
The pressure sensor according to any one of claims 1 to 3, wherein the adjustment electrode is not formed at a position corresponding to an apex of the mountain-shaped pressure-sensitive layer.
The pressure sensor according to claim 4, wherein the adjustment electrode is disposed at a position shifted in one direction from the apex of the mountain-shaped pressure-sensitive layer.
The semiconductor device further comprises an insulating layer that is formed on a part of the electrode to insulate the part and that configures a portion exposed to the mountain-shaped pressure-sensitive layer of the electrode as the adjustment electrode. The pressure sensor according to any one of 1 to 5.
The pressure sensor according to any one of claims 1 to 6, further comprising a temperature sensitive element formed side by side on the plurality of adjustment electrodes.
The pressure sensor according to claim 7, wherein the temperature sensing element functions as a spacer by being closer to the common electrode than the plurality of mountain-shaped pressure sensitive layers.
A pressure detector that detects pressure values by signals from the plurality of adjustment electrodes and the plurality of mountain-shaped pressure-sensitive layers;
A temperature detection unit for detecting a temperature value by a signal from the temperature sensing element;
A pressure correction unit for correcting the temperature of the pressure value based on the temperature value from the temperature detection unit;
The pressure sensor according to claim 7 or 8, further comprising: