JP6914816B2 - Pressure sensor - Google Patents

Description

The present invention relates to a pressure sensor, particularly a pressure sensor having a pressure sensitive layer and a thin film transistor as a large number of electrodes.

As a pressure sensor, a pressure sensor in which a large number of thin film transistors are combined is known (see, for example, Patent Document 1).
The pressure-sensitive resin is one in which conductive particles are dispersed in an insulating resin such as silicone rubber. In the pressure-sensitive resin, when pressure is applied, the conductive particles come into contact with each other in the insulating resin, so that the resistance value decreases. As a result, the pressure applied to the pressure-sensitive resin can be detected.
A large number of thin film transistors are arranged in a matrix and function as electrodes. In this case, pressure detection can be speeded up and power consumption can be reduced.

Japanese Unexamined Patent Publication No. 2016-4940

Further, there is also known a pressure sensor in which a pressure sensitive layer and a plurality of electrodes are arranged so as to face each other with a predetermined gap.
Generally, the pressure sensor has a problem that the pressure measuring range of the pressure sensitive layer is narrow. Specifically, in the pressure-electric resistance characteristic, the rate of change in electrical resistance is large in the range of low pressure, but the rate of change in electrical resistance is small in the range of high pressure. The reason is that even if the pressure is high, the contact area between the pressure sensitive layer and the electrode does not increase from the middle, that is, the contact resistance does not follow the pressure. As a result, in a large pressure range, the pressure cannot be measured accurately due to insufficient sensitivity.

An object of the present invention is to widen the pressure measurement range that can be accurately measured in a pressure sensor having electrodes arranged so as to be spaced apart from each other.

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

The pressure sensor according to the viewpoint of the present invention is used in a state of being mounted along a curved surface, and includes a common electrode, a plurality of individual electrodes, a plurality of thin film transistors, and a first individual pressure-sensitive layer. , A second individual pressure sensitive layer is provided.
The common electrode is formed so as to spread over one surface.
The plurality of individual electrodes are provided in a matrix so as to face the common electrode.
The plurality of thin film transistors are provided on the opposite side of the common electrode of the plurality of individual electrodes corresponding to the plurality of individual electrodes, and one or two or more adjacent electrodes are connected to one individual electrode.
The first individual pressure-sensitive layer is laminated on the surface of the first individual electrode on the common electrode side of the plurality of individual electrodes.
The second individual pressure-sensitive layer is laminated on the surface of the second individual electrode on the common electrode side of the plurality of individual electrodes.
The gap between the first individual pressure sensitive layer and the common electrode is shorter than the gap between the second individual pressure sensitive layer and the common electrode.
The first individual pressure-sensitive layer has a first portion and a second portion having a larger area than the first portion and formed under the first portion to form a first constricted portion near the boundary with the first portion. Have.

In this pressure sensor, when the pressure is small, only the first individual pressure sensitive layer comes into contact with the common electrode. As a result, the resistance change (that is, pressure) of the first individual pressure-sensitive layer can be accurately measured via the first electrode.
When the pressure is high, the second individual pressure sensitive layer comes into contact with the common electrode in addition to the first individual pressure sensitive layer. As a result, the resistance change (that is, pressure) of the second individual pressure-sensitive layer can be accurately measured via the second electrode. This is because the gap between the second individual pressure sensitive layer and the common electrode is long, so the pressure measurement range in which the electrical resistance can be accurately measured is shifted to the higher pressure side than that of the first individual pressure sensitive layer, that is, high. This is because it corresponds to pressure.

More specifically, when the pressing force acts on the common electrode, in the first individual pressure sensitive layer, the first part and the second part come into contact with the common electrode from the initial stage where only the first part contacts the common electrode. It changes to the next stage. Therefore, the change in the contact resistance of the first individual pressure-sensitive layer is large. As a result, the accuracy of the low pressure measurement area is improved.
Since the pressure sensor is used in a state of being mounted along a curved surface, the common electrode faces the first individual pressure-sensitive layer in a curved state. Therefore, unlike the above aspect, when the first individual pressure sensitive layer does not have the first constricted portion, the common electrode is brought into close contact with the entire first individual pressure sensitive layer almost at the same time, and therefore the change in contact resistance is large. There is a risk that it will not be. On the other hand, in this embodiment, since the first individual pressure sensitive layer has the first constricted portion, it is possible to reliably obtain the stage where the common electrode contacts only the first portion.
The transition of the contact state between the common electrode and the first individual pressure-sensitive layer will be described in detail. As the pressure increases, the common electrode first contacts the first portion of the first individual pressure sensitive layer, then the first and second portions (but excluding the first constriction), and then. It comes into contact with the first constriction. In this way, the contact area increases in the process of filling the first constricted portion. In the end, the common electrode may end in contact with all the first constricted portions, or may end with a space remaining behind the first constricted portion.

The first individual pressure-sensitive layer may have a third portion which has a larger area than the second portion and is formed under the second portion to form a second constricted portion near the boundary with the second portion. ..

The second individual pressure-sensitive layer has a fourth portion and a fifth portion which has a larger area than the fourth portion and is formed under the fourth portion to form a third constricted portion near the boundary with the fourth portion. You may have.
In this case, individual pressure-sensitive layers having different numbers of stages are provided, and the number of individual pressure-sensitive layers for low pressure detection is larger than the number of individual pressure-sensitive layers for high pressure detection. Therefore, the change in the contact resistance of the pressure-sensitive layer in the measurement of low pressure can be sufficiently large.

The pressure sensor has a pressing area and
In the pressing region, the first electrode and the second electrode may be arranged so as to be included in the minimum pressing area at any pressing location. The "minimum pressing area" is the minimum area that is assumed to be pressed whenever a planned pressing object (for example, a finger) presses the pressure sensor.
In this pressure sensor, the low pressure is accurately measured by the first electrode and the high pressure is accurately measured by the second electrode regardless of which pressing portion in the pressing region is pressed.

The pressure sensor may further include a third individual pressure-sensitive layer laminated on the surface of the third electrode of the plurality of individual electrodes on the common electrode side.
The area of the first electrode may be larger than the area of the second electrode. This alleviates the difference in resistance value for each element.
The pressure-sensitive material of the first pressure-sensitive layer may have a lower resistance value than the pressure-sensitive material of the second pressure-sensitive layer. This alleviates the difference in resistance value for each element.

The pressure sensor according to another aspect of the present invention is used in a state of being mounted along a curved surface, and includes a common electrode, a plurality of individual electrodes, a plurality of thin film transistors, a common pressure sensitive layer, and the like. It includes a first individual pressure-sensitive layer and a second individual pressure-sensitive layer.
The common electrode is formed so as to spread over one surface.
The plurality of individual electrodes are provided in a matrix so as to face the common electrode.
The plurality of thin film transistors are provided on the opposite side of the common electrode of the plurality of individual electrodes corresponding to the plurality of individual electrodes, and one or two or more adjacent electrodes are connected to one individual electrode.
The common pressure sensitive layer is laminated on the surface of the common electrode on the side of a plurality of individual electrodes.
The first individual pressure-sensitive layer is laminated on the surface of the first individual electrode on the common electrode side of the plurality of individual electrodes.
The second individual pressure-sensitive layer is laminated on the surface of the second individual electrode on the common electrode side of the plurality of individual electrodes.
The gap between the first individual pressure sensitive layer and the common pressure sensitive layer is shorter than the gap between the second individual pressure sensitive layer and the common pressure sensitive layer.
The first individual pressure-sensitive layer has a first portion and a second portion having a larger area than the first portion and formed under the first portion to form a first constricted portion near the boundary with the first portion. Have.

In this pressure sensor, when the pressure is small, only the first individual pressure sensitive layer comes into contact with the common pressure sensitive layer. As a result, the resistance change (that is, pressure) of the common pressure-sensitive layer and the first individual pressure-sensitive layer can be accurately measured via the first electrode.
When the pressure is high, the second individual pressure sensitive layer comes into contact with the common pressure sensitive layer in addition to the first individual pressure sensitive layer. As a result, the resistance change (that is, pressure) of the common pressure-sensitive layer and the second individual pressure-sensitive layer can be accurately measured via the second electrode. This is because the gap between the second individual pressure sensitive layer and the common pressure sensitive layer is long, so that the pressure measurement range in which the electrical resistance can be accurately measured is shifted to the higher pressure side of the first individual pressure sensitive layer. In other words, it corresponds to high pressure.

More specifically, when the pressing force acts on the common pressure sensitive layer, in the first individual pressure sensitive layer, from the initial stage where only the first portion contacts the common pressure sensitive layer, the first portion and the second portion It changes to the next stage of contact with the common pressure sensitive layer. Therefore, the change in contact resistance while the first individual pressure-sensitive layer is compressed is large. As a result, the accuracy of the low pressure measurement area is improved.
Since the pressure sensor is used in a state of being mounted along a curved surface, the common pressure-sensitive layer faces the first individual pressure-sensitive layer in a curved state. Therefore, unlike the above aspect, when the first individual pressure sensitive layer does not have the first constriction portion, the common pressure sensitive layer adheres to the entire first individual pressure sensitive layer almost at the same time, and therefore the contact resistance changes. It may not be large. On the other hand, in the present embodiment, since the first individual pressure-sensitive layer has the first constricted portion, it is possible to surely obtain the stage where the common pressure-sensitive layer contacts only the first portion.
The transition of the contact state between the common pressure-sensitive layer and the first individual pressure-sensitive layer will be described in detail. As the pressure increased, the common pressure sensitive layer first contacted the first portion of the first individual pressure sensitive layer, then the first and second portions (except for the first constriction). Next, it comes into contact with the first constriction. In this way, the contact area increases in the process of filling the first constricted portion. In the end, the common pressure-sensitive layer may end in contact with all the first constricted portions, or may end with a space remaining behind the first constricted portion.

The first individual pressure-sensitive layer may have a third portion which has a larger area than the second portion and is formed under the second portion to form a second constricted portion near the boundary with the second portion. ..
The second individual pressure-sensitive layer has a fourth portion and a fifth portion which has a larger area than the fourth portion and is formed under the fourth portion to form a third constriction near the boundary with the fourth portion. You may be doing it.

The pressure sensor has a pressing area and
In the pressing region, the first electrode and the second electrode may be arranged so as to be included in the minimum pressing area at any pressing location.
In this pressure sensor, the low pressure is accurately measured by the first electrode and the high pressure is accurately measured by the second electrode regardless of which pressing portion in the pressing region is pressed.

The pressure sensor may further include a third individual pressure-sensitive layer laminated on the surface of the third electrode of the plurality of individual electrodes on the common electrode side. The gap between the third individual pressure sensitive layer and the common pressure sensitive layer is longer than the gap between the second individual pressure sensitive layer and the common pressure sensitive layer.

The pressure sensor has a pressing area and
In the pressing region, the first electrode, the second electrode, and the third electrode may be arranged so as to be included in the minimum pressing area at any pressing location.

The first individual pressure-sensitive layer may have a third portion which has a larger area than the second portion and is formed under the second portion to form a second constricted portion near the boundary with the second portion. ..

The second individual pressure-sensitive layer has a fourth portion and a fifth portion which has a larger area than the fourth portion and is formed under the fourth portion to form a third constriction near the boundary with the fourth portion. You may be doing it.

The pressure sensor may have a pressing area.
In the pressing region, the first electrode and the second electrode may be arranged so as to be included in the minimum pressing area at any pressing location.
In this pressure sensor, the low pressure is accurately measured by the first electrode and the high pressure is accurately measured by the second electrode regardless of which pressing portion in the pressing region is pressed.

The pressure sensor may further include a third individual pressure-sensitive layer laminated on the surface of the third electrode of the plurality of individual electrodes on the common electrode side. The gap between the third individual pressure sensitive layer and the common pressure sensitive layer is longer than the gap between the second individual pressure sensitive layer and the common pressure sensitive layer.
The area of the first electrode may be larger than the area of the second electrode. This alleviates the difference in resistance value for each element.
The pressure-sensitive material of the first pressure-sensitive layer may have a lower resistance value than the pressure-sensitive material of the second pressure-sensitive layer. This alleviates the difference in resistance value for each element.

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

The schematic perspective view which shows the use state of the pressure sensor which concerns on 1st Embodiment of this invention. The schematic diagram for demonstrating the basic structure of the pressure sensor of 1st Embodiment. Schematic cross-sectional view of the pressure sensor. The partial schematic sectional view of the 1st electrode and the 1st pressure sensitive layer of a pressure sensor. The schematic plan view of the lower electrode member of a pressure sensor. The schematic plan view of the 1st electrode and the 1st pressure sensitive layer of a pressure sensor. The schematic plan view which shows the individual electrode arrangement. Equivalent circuit diagram of pressure sensor. FIG. 6 is a schematic cross-sectional view of a first electrode and a first pressure-sensitive layer of a pressure sensor in a state where pressure is applied. FIG. 6 is a schematic cross-sectional view of a first electrode and a first pressure-sensitive layer of a pressure sensor in a state where pressure is applied. FIG. 6 is a schematic cross-sectional view of a first electrode and a first pressure-sensitive layer of a pressure sensor in a state where pressure is applied. Schematic cross-sectional view of the pressure sensor under pressure. Schematic cross-sectional view of the pressure sensor under pressure. The graph which shows the relationship between the pressure of a pressure sensor and the electric resistance. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. The schematic cross-sectional view which shows the manufacturing method of a pressure sensor. A partial schematic cross-sectional view of the pressure sensor according to the second embodiment. A partial schematic cross-sectional view of the pressure sensor according to the third embodiment. A partial schematic cross-sectional view of the pressure sensor according to the fourth embodiment. The schematic diagram for demonstrating the basic structure of the pressure sensor of 5th Embodiment. Schematic cross-sectional view of the pressure sensor. The schematic plan view which shows the individual electrode arrangement. Schematic cross-sectional view of the pressure sensor in other variants. Schematic cross-sectional view of the pressure sensor in other variants. Schematic cross-sectional view of the pressure sensor in other variants.

1. 1. First Embodiment (1) Application and Basic Principle of Pressure Sensor The usage status of the pressure sensor according to the present invention will be described with reference to FIG. The pressure sensor is used in a state of being mounted along a curved surface. FIG. 1 is a schematic perspective view showing a usage state of the pressure sensor according to the first embodiment of the present invention.
In FIG. 1, the pressure sensor 1 is attached to the handle H of the bicycle for pressure measurement. When the subject grasps the handle H, the pressure sensor 1 measures the magnitude, distribution, and changes in the pressure.

The basic structure of the pressure sensor 1 will be described with reference to FIG. FIG. 2 is a schematic diagram for explaining the basic structure of the pressure sensor of the first embodiment.
The pressure sensor 1 is, for example, a cylindrical or strip-shaped member wound around a columnar handle H. In FIG. 2, the pressure sensor 1 has an inner sheet 102 and an outer sheet 103. A large number of pressure-sensitive layers 33 are formed on the upper surface of the inner sheet 102. The large number of pressure-sensitive layers 33 include a large number of first pressure-sensitive layers 33Z, a second pressure-sensitive layer 33Y, and a third pressure-sensitive layer 33X. The first pressure-sensitive layer 33Z is the highest, and the third pressure-sensitive layer 33X is the lowest. The functions of a large number of pressure sensitive layers 33 will be described later. Note that FIG. 2 is a diagram for explaining a rough configuration, and the scale and the number of pressure sensitive layers 33 are different from the actual ones.

(2) Basic Configuration of Pressure Sensor The pressure sensor 1 according to the first embodiment will be described with reference to FIGS. 3 to 8. FIG. 3 is a schematic cross-sectional view of the pressure sensor according to the first embodiment of the present invention. FIG. 4 is a partial schematic cross-sectional view of the first electrode of the pressure sensor and the first pressure sensitive layer. FIG. 5 is a schematic plan view of the lower electrode member of the pressure sensor. FIG. 6 is a schematic plan view of the first electrode of the pressure sensor and the first pressure sensitive layer. FIG. 7 is a schematic plan view showing the arrangement of individual electrodes. FIG. 8 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. The pressure sensor 1 is used by being attached to a member having a curved surface. Therefore, as shown in FIGS. 3 and 4, the pressure sensor 1 is used in a curved shape. In addition, in FIGS. 3 and 4, the entire pressure sensor 1 is bent in a convex shape.
The pressure sensor 1 has an upper electrode member 3. The upper electrode member 3 is a flat 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 lower surface of the insulating film 7 so as to be spread over the entire surface, that is, one surface or patterned.

As shown in FIGS. 3 and 4, the pressure sensor 1 has a lower electrode member 5. The lower electrode member 5 is a planar member arranged below the upper electrode member 3. The lower electrode member 5 includes, for example, a rectangular insulating film 15 and a plurality of individual electrodes 31 (first electrode 31Z, second electrode 31Y, third electrode 31X in FIGS. 3 and 4) formed on the upper surface thereof. Have. The individual electrode 31 is also referred to as a pixel electrode.
As shown in FIG. 4, the upper electrode member 3 and the lower electrode member 5 are adhered to each other by the frame spacer 13 at the peripheral edge portion. The frame spacer 13 is formed in the shape of a frame, and is made of, for example, an adhesive and double-sided tape.

The lower electrode member 5 has a large number of pressure-sensitive layers 33 (in FIGS. 3 and 4, the first pressure-sensitive layer 33Z, the second pressure-sensitive layer 33Y, and the third pressure-sensitive layer 33X). A large number of pressure-sensitive layers 33 are formed on the common electrode 9 side of a large number of individual electrodes 31, respectively. Briefly, as shown in FIGS. 3 and 4, the pressure sensitive layer 33 covers the entire individual electrode 31 and has a slightly larger outer diameter. Therefore, in a plan view, the individual electrodes 31 are hidden by the pressure sensitive layer 33.
As shown in FIG. 5, the plurality of individual electrodes 31 and the pressure-sensitive layer 33 are spread over a flat surface as a whole, and are arranged in a matrix, for example. The matrix shape means a state in which two-dimensional arrangement is performed in a matrix shape or a shape similar thereto. The electrode pitch is, for example, 0.3 to 3.0 mm, preferably 0.3 to 1.5 mm, and more preferably 0.3 to 0.7 mm.

The pressure sensitive layer 33 is convex and has a top (or center) portion, a peripheral portion, and a smooth curved surface between them. The pressure sensitive layer 33 may have a dome shape, a cone shape, or a frustum shape. The pressure sensitive layer 33 includes a circle, a square, and other shapes.
By having the above shape, the contact area between the common electrode 9 and the pressure sensitive layer 33 increases according to the pressure. Further, the thickness of the pressure sensitive layer 33 becomes smaller toward the outer periphery, and the resistance value decreases. In other words, when the pressure is low, only the apex (center in the radial direction) of the 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 radial intermediate portion or the outer peripheral portion of the pressure sensitive layer 33, and the contact area is large.

As an example, in FIG. 4, the height H of the 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 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.
Since the outer diameter of the individual electrode 31 is formed so as to extend to a position slightly shorter than the outer diameter of the pressure sensitive layer 33, the following effects can be obtained. When the pressure is low, the conductive path of the pressure sensitive layer 33 (the shortest distance between the common electrode 9 passing through the pressure sensitive layer 33 and the individual electrode 31) is long and the resistance value is high. When the pressure is high, the conductive path of the pressure sensitive layer 33 is short and the resistance value is low. In this embodiment, since the plane shapes of the individual electrodes 31 and the pressure sensitive layer 33 are both circular, the short portion of the conductive path extends from the center to the outer peripheral side in a circular shape in a plan view. That is, each portion of the individual electrode 31 in the circumferential direction is a sensitizing portion extending outward in the radial direction from the central portion.

As shown in FIG. 3, the plurality of pressure-sensitive layers 33 include a first pressure-sensitive layer 33Z for low pressure detection (an example of a first individual pressure-sensitive layer) and a second pressure-sensitive layer 33Y for medium pressure detection (an example of the first individual pressure-sensitive layer). It has a second individual pressure sensitive layer (an example) and a third pressure sensitive layer 33X (an example of a third individual pressure sensitive layer) for detecting high pressure. The first pressure-sensitive layer 33Z is laminated on the surface of the first electrode 31Z on the common electrode 9 side of the plurality of individual electrodes 31. The second pressure-sensitive layer 33Y is laminated on the surface of the second electrode 31Y on the common electrode 9 side of the plurality of individual electrodes 31. The third pressure-sensitive layer 33X is laminated on the surface of the third electrode 31X on the common electrode 9 side of the plurality of individual electrodes 31.
The gap P3 between the third pressure-sensitive layer 33X and the common electrode 9 is the largest, and the gap P1 between the first pressure-sensitive layer 33Z and the common electrode 9 is the smallest. P1 is, for example, zero (that is, the common electrode 9 and the first pressure sensitive layer 33Z are in contact with each other in the initial state).

The total thickness of the first pressure-sensitive layer 33Z, the second pressure-sensitive layer 33Y, and the third pressure-sensitive layer 33X, and the gaps P1 to P3 can be appropriately set from a wide range. For example, it is 0 to several tens of μm, and may be on the order of several μm or tens of μm.
For example, the total thickness of the first pressure-sensitive layer 33Z is 50 to 70 μm, the total thickness of the second pressure-sensitive layer 33Y is 30 to 50 μm, and the total thickness of the third pressure-sensitive layer 33X is 5 to 25 μm.

It is preferable to set the height difference in the pressure sensitive layer according to the radius of curvature of the curved surface. As an example, as the radius of curvature R of the curved surface decreases, the difference between the thickness of the first pressure-sensitive layer 33Z and the thickness of the second pressure-sensitive layer 33Y increases. As a result, the detection accuracy in the low pressure to medium pressure region is improved.
From the above, the first electrode 31Z on which the first pressure sensitive layer 33Z is formed functions as an individual electrode for low pressure detection. The second electrode 31Y on which the second pressure sensitive layer 33Y is formed functions as an individual electrode for detecting medium pressure. The third electrode 31X on which the third pressure sensitive layer 33X is formed functions as an individual electrode for detecting high pressure.

As shown in FIGS. 4 and 6, the first pressure-sensitive layer 33Z is formed under the first portion 33A in a larger area than the first portion 33A and near the boundary between the first portion 33A and the first portion 33A. It has a second portion 33B forming a first constriction portion 51. Here, the constricted portion is a stepped portion formed at the boundary between the steps and has a concave shape. In other words, the first portion 33A is a step formed on the second portion 33B and has a smaller area than the second portion 33B.
As described above, the constricted portion means a stepped portion of a staircase structure in which a small area portion is formed on a large area portion.

In this pressure sensor 1, when the pressure is small, only the first pressure sensitive layer 33Z comes into contact with the common electrode 9. As a result, the resistance change (that is, pressure) of the first pressure sensitive layer 33Z can be accurately measured via the first electrode 31Z.
When the pressure is high, the second pressure sensitive layer 33Y comes into contact with the common electrode in addition to the first pressure sensitive layer 33Z. As a result, the resistance change (that is, pressure) of the second pressure sensitive layer 33Y can be accurately measured via the second electrode 31Y. This is because the gap between the second pressure sensitive layer 33Y and the common electrode 9 is long, so that the pressure measurement range in which the electrical resistance can be accurately measured is shifted to the higher pressure side of the first pressure sensitive layer 33Z, that is, This is because it corresponds to high pressure.

More specifically, when the pressing force acts on the insulating film 7, in the first pressure sensitive layer 33Z, from the initial stage where only the first portion 33A contacts the common electrode 9, the first portion 33A and the second portion 33B Changes to the next stage of contact with the common electrode 9. Therefore, the change in contact resistance while the first pressure-sensitive layer 33Z is compressed is large. As a result, the accuracy of the low pressure measurement area is improved.
The first pressure sensitive layer 33Z has a third portion 33C. The third portion 33C is formed under the second portion 33B in a larger area than the second portion 33B, and forms the second constricted portion 52 near the boundary with the second portion 33B. In other words, the second portion 33B is a step formed on the third portion 33C and has a smaller area than the third portion 33C. From the above, the first pressure sensitive layer 33Z has a three-stage structure. More specifically, each step of the pressure sensitive layer 33 has a smooth convex shape, is circular in a plan view, and is centered in a plan view.
Since the pressure sensor 1 is used in a state of being mounted along a curved surface, as shown in FIG. 34, the common electrode 9 faces the first pressure sensitive layer 33Z in a curved state. Therefore, unlike the above aspect, when the first individual pressure sensitive layer does not have the first constricted portion, the common electrode is brought into close contact with the entire first individual pressure sensitive layer almost at the same time, and therefore the change in contact resistance is large. There is a risk that it will not be. On the other hand, in this embodiment, since the first pressure-sensitive layer 33Z has the first constricted portion 51, it is possible to reliably obtain the stage where the common electrode 9 contacts only the first portion 33A.

As shown in FIG. 3, the second pressure-sensitive layer 33Y is formed under the fourth portion 33D and the fourth portion 33D to form a third constriction portion 53 near the boundary between the fourth portion 33D and the fourth portion 33D. It has a portion 33E and. That is, the fourth portion 33D is a step formed on the fifth portion 33E, and is a portion having a smaller area than the fifth portion 33E. From the above, the second pressure sensitive layer 33Y has a two-stage configuration. In this way, also in the second pressure sensitive layer 33Y, the initial stage in which only the fourth portion 33D abuts on the common electrode 9 and the next stage in which the fourth portion 33D and the fifth portion 33E abut on the common electrode 9 Can be realized.
The third pressure-sensitive layer 33X does not have a constricted portion and has a simple convex shape. That is, the third pressure sensitive layer 33X has a one-stage configuration.
From the above, the individual pressure-sensitive layers having different numbers of stages are provided, and the number of stages of the individual pressure-sensitive layers for low pressure detection is larger than the number of stages of the individual pressure-sensitive layers for high pressure detection. Therefore, the change in the contact resistance of the pressure-sensitive layer in the measurement of low pressure can be sufficiently large. Specifically, a three-stage first pressure-sensitive layer 33Z, a two-stage second pressure-sensitive layer 33Y, and a first-stage third pressure-sensitive layer 33X are provided.

The pressure sensor 1 has a pressing region. In the pressing region, the first electrode 31Z, the second electrode 31Y, and the third electrode 31X are arranged so as to be included in the minimum pressing area at any pressing location. The "minimum pressing area" is the minimum area that is assumed to be pressed whenever a planned pressing object (for example, a finger) presses the pressure sensor.
The pressing region may be the entire pressure sensor 1 or a part of the pressure sensor 1.

As shown in FIG. 7, the first pressure-sensitive layer 33Z, the second pressure-sensitive layer 33Y, and the third pressure-sensitive layer 33X are appropriately dispersed and arranged. In this embodiment, the minimum pressing area is a region of 3 × 3, and when any portion is pressed, the first pressure-sensitive layer 33Z, the second pressure-sensitive layer 33Y, and the third pressure-sensitive layer 33X are at least 1. Individuals correspond.
When the region of the common electrode 9 is pushed down toward the pressure sensitive layer 33, the common electrode 9 and the individual electrodes 31 located in the push-down region are electrically conductive. Pushing down may be performed with, for example, fingers, palms, or soles of the feet.

(3) Relationship between TFT and Individual Electrode The lower electrode member 5 has a plurality of thin film transistors 30 (hereinafter referred to as “TFT30”). Each TFT 30 is provided corresponding to each of the individual electrodes 31, and functions as an electrode for detecting a current value.
As shown in FIG. 4, the TFT 30 has a source electrode 17, a drain electrode 19, and a gate electrode 21. The TFT 30 is a top gate type. The materials constituting the gate electrode, the source electrode and the drain electrode are not particularly limited.

The source electrode 17 and the drain electrode 19 are formed on the upper surface of the insulating film 15. The TFT 30 has an organic semiconductor 23 formed between the source electrode 17 and the drain electrode 19. As a material constituting such a semiconductor layer, known materials such as silicon, oxide semiconductors, and organic semiconductors 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 organic semiconductor 23.

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

The operating 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 pressure sensitive layer 33 flows. Then, as the pressure applied to the pressure sensitive layer 33 increases, the resistance decreases, so that an increase in the drain current is detected. The pressure distribution on the sheet surface can be observed by sweeping the TFT 30 on the pressure sensor 1, applying a gate voltage, and measuring the drain current.

The pressure sensor 1 has a circuit unit (not shown). The circuit unit controls the drain electrode 19, the source electrode 17, and the common electrode 9, and depends on, for example, the power supply voltage for applying a predetermined voltage to the common electrode 9, the source electrode 17, and the current value between the source and drain. It has a current detection circuit that generates a new signal and outputs it to an external signal processing device. The external signal processing device detects the pressing position and pressing pressure based on the signal sent from the circuit unit.

(4) Pressing operation and pressure measuring operation The pressing operation and the pressure measuring operation will be described with reference to FIGS. 9 to 14. 9 to 11 are schematic cross-sectional views of the first electrode and the first pressure-sensitive layer of the pressure sensor in a state where pressure is applied. 12 to 13 are schematic cross-sectional views of the pressure sensor in a state where pressure is applied. FIG. 14 is a graph showing the relationship between the pressure of the pressure sensor and the electrical resistance.
As shown in FIG. 14, when pressure is applied, the resistance of the 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 pressure sensitive layer 33 connected in series with the drain electrode 19. As a result, the potential difference between the source and the drain becomes large, and the amount of flowing current increases. Therefore, if the pressing force applied to the pressure sensitive layer 33 and the amount of current are acquired in advance, the signal processing device (not shown) applies the pressure sensor 1 to the pressure sensor 1 by reading the change in the signal according to the amount of current. The amount of pressure (pressing pressure) can be detected.

Hereinafter, the above operation will be described in more detail.
In this pressure sensor 1, when the pressure is low, only the first electrode 31Z comes into contact with the common electrode 9. As a result, as shown in FIG. 14, the resistance change (that is, pressure) of the pressure sensitive layer 33 can be accurately measured via the first electrode 31Z.
When the pressure is high, the second electrode 31Y comes into contact with the common electrode 9 in addition to the first electrode 31Z. As a result, as shown in FIG. 14, the resistance change (that is, pressure) of the pressure sensitive layer 33 can be accurately measured via the second electrode 31Y. This is because the gap between the second electrode 31Y and the common electrode 9 is long, so that the pressure measurement range in which the electrical resistance can be accurately measured is shifted to the higher pressure side of the first electrode 31Z, that is, higher. This is because it corresponds to pressure.

When the pressure is higher, the third electrode 31X comes into contact with the common electrode 9 in addition to the first electrode 31Z and the second electrode 31Y. As a result, as shown in FIG. 14, the resistance change (that is, pressure) of the pressure sensitive layer 33 can be accurately measured via the third electrode 31X. This is because the gap between the third electrode 31X and the common electrode 9 is long, so that the pressure measurement range in which the electrical resistance can be accurately measured is shifted to the higher pressure side of the second electrode 31Y, that is, it is higher. This is because it corresponds to pressure.
In this pressure sensor 1, the low pressure is accurately measured by the first electrode 31Z, the medium pressure is accurately measured by the second electrode 31Y, and the third electrode 31X is accurately measured regardless of which pressing portion in the pressing region is pressed. Accurately measures high pressure.
As described above, since the region where the rate of resistance change of each electrode is sufficiently high is shifted according to the load, accurate measurement can be performed at any of low pressure, medium pressure, and high pressure.

The contact operation between the common electrode 9 and the first pressure-sensitive layer 33Z, the second pressure-sensitive layer 33Y, and the third pressure-sensitive layer 33X will be described in detail below.
In FIGS. 3 and 9, a small force F1 acts on the upper electrode member 3, so that the common electrode 9 is in contact with only the first pressure sensitive layer 33Z. More precisely, the common electrode 9 is in contact with only the apex of the first portion 33A of the first pressure sensitive layer 33Z.

In FIGS. 10 and 12, a medium force F2 acts on the upper electrode member 3, so that the common electrode 9 is in contact with the first portion 33A and the second portion 33B of the first pressure sensitive layer 33Z. That is, in the first pressure-sensitive layer 33Z, the common electrode 9 is in contact with only the apex of the first portion 33A, and the common electrode 9 is in contact with the first portion 33A and the second portion 33B. I understand. Thereby, the low pressure can be accurately measured by the output from the TFT 30 corresponding to the first electrode 31Z. In the above case, the common electrode 9 is not in contact with the first constricted portion 51.
Further, in FIG. 12, the common electrode 9 is also in contact with the second pressure sensitive layer 33Y. More precisely, the common electrode 9 is in contact only with the top of the fourth portion 33D of the second pressure sensitive layer 33Y.

When the pressing force is further increased, the common electrode 9 proceeds in the order of contacting the entire first portion 33A (see FIGS. 11 and 13) and contacting the third portion 33C.
In FIG. 13, a large force F3 acts on the upper electrode member 3, and the common electrode 9 comes into contact with the first constricted portion 51. In this way, the contact area increases in the process of filling the first constricted portion 51. In FIGS. 11 and 13, the common electrode 9 is in contact with all of the first constricted portions 51. However, it may end with a space remaining behind the first constricted portion 51. The above description is the same for the second constriction portion 52.
In FIG. 13, the common electrode 9 is in contact with most of the fourth portion 33D of the second pressure sensitive layer 33Y, but is not in contact with the third constricted portion 53. That is, from the stage where the common electrode 9 abuts only on the top of the fourth portion 33D in the second pressure-sensitive layer 33Y, the common electrode 9 contacts most of the fourth portion 33D (contacts the third constriction 53). It can be seen that it is moving to the stage. As a result, the medium pressure can be accurately measured by the output from the TFT 30 corresponding to the second electrode 31Y.
When the pressing force is further increased, the common electrode 9 proceeds to the stage of contacting the fourth portion 33D and the fifth portion 33E of the second pressure sensitive layer 33Y (excluding the third constriction portion 53), and further, the third portion 3 Proceed to the stage of contacting the constricted portion 53.
In addition, in FIGS. 13 and 11, the common electrode 9 is also in contact with the third electrode 31X.

It is preferable that the insulating film 7 and the common electrode 9 have elasticity. As a result, when pressure is applied, the followability of the common electrode 9 to the pressure sensitive layer 33 is improved. In other words, when the pressure is high, the common electrode 9 tends to adhere to the outer peripheral side of the pressure sensitive layer 33 (the thin portion of the pressure sensitive layer 33). As a result, the difference in the contact resistance of the pressure sensitive layer 33 becomes large, that is, the measurement range becomes large.
Further, 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 lost is improved. As a result, the reproducibility of repeated measurements is improved.

Generally, when pressure is applied to the insulating film 7 and the common electrode 9, a large area of deflection occurs, but the load is concentrated on a plurality of small area pressure sensitive layers and electrodes, and in that case, There was a risk that the insulating film 7 and the common electrode 9 would be cracked or deformed. However, in the present embodiment, since the insulating film 7 and the common electrode 9 have elasticity, the common electrode 9 is less likely to be cracked or deformed in the 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 part as described above, the contact area does not change any more when the common electrode 9 completely contacts the outer peripheral edge of the pressure sensitive layer 33, so that the pressure measurement range is wide. Although it becomes narrower, the pressure resolution becomes larger because the difference in contact area is large. The thickness and hardness of the base material are appropriately selected according to the range to be measured.

(5) Materials The insulating film 7 and the insulating film 15 include engineering plastics such as polycarbonate, polyamide, and polyether ketone, or resin films such as acrylic, polyethylene terephthalate, and polybutylene terephthalate. Can be used.
The common electrode 9 and the individual electrode 31 include a metal oxide film such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, or indium tin oxide (ITO), and a composite mainly composed of these metal oxides. It can be formed by a film or a metal film such as gold, silver, copper, tin, nickel, aluminum, copper alloy, or palladium.
The pressure-sensitive layer 33 is made of, for example, pressure-sensitive ink. The pressure-sensitive ink is a material that enables pressure detection by changing the contact resistance with the facing electrode according to 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 coating with a dispenser can be used.

(6) Manufacturing Method of Pressure Sensor The manufacturing method of the pressure sensor 1 will be described with reference to FIGS. 15 to 26. 15 to 26 are schematic cross-sectional views showing a method of manufacturing a pressure sensor.

First, each step of the method of manufacturing the lower electrode member 5 will be described with reference to FIGS. 15 to 25.
As shown in FIG. 15, the electrode material 37 is formed on one surface of the insulating film 15 by, for example, sputtering.
As shown in FIG. 16, the film exposed portion 39 is formed by removing a part of the electrode material 37 by, for example, a photolithography method. Further, as a result, the source electrode 17 and the drain electrode 19 are formed. The method of forming the source electrode 17 and the drain electrode 19 is not particularly limited.

As shown in FIG. 17, the organic semiconductor 23 is formed in the film exposed portion 39. The method for forming the organic semiconductor 23 is a known technique.
As shown in FIG. 18, the first insulating film 25 is formed so as to cover the surfaces on which the source electrode 17, the drain electrode 19, and the organic semiconductor 23 are formed.
As shown in FIG. 19, the gate electrode 21 is formed above the organic semiconductor 23 on the upper surface of the first insulating film 25. The method for forming the gate electrode 21 is a known technique.

As shown in FIG. 20, the second insulating film 27 is formed so as to cover the entire first insulating film 25 in which the gate electrode 21 is formed.
As shown in FIG. 21, a through hole leading to 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 is embedded therein to form a conductive portion 29.
As shown in FIG. 22, the first electrode 31Z, the second electrode 31Y, and the third electrode 31X are formed by a printing method and connected to the TFT 30 via the conductive portion 29.

Next, the first pressure-sensitive layer 33Z, the second pressure-sensitive layer 33Y, and the third pressure-sensitive layer 33X are formed.
As shown in FIG. 23, a large area third portion 33C is formed on the individual electrodes 31 by a printing method. This is done for all pressure sensitive layers. As a result, the third pressure sensitive layer 33X is completed.
As shown in FIG. 24, a medium-area second portion 33B is formed on the third portion 33C by a printing method. This is performed only for the first pressure sensitive layer 33Z and the second pressure sensitive layer 33Y. As a result, the second pressure-sensitive layer 33Y is completed.
As shown in FIG. 25, a small area first portion 33A is formed on the second portion 33B by a printing method. This is done only for the first pressure sensitive layer 33Z. As a result, the first pressure-sensitive layer 33Z is completed.
As described above, a step is created in the pressure sensitive layer by changing the print size for each step.
As a result, the first pressure-sensitive layer 33Z, the second pressure-sensitive layer 33Y, and the third pressure-sensitive layer 33X are completed.

Next, the production of the upper electrode member 3 will be described with reference to FIG.
As shown in FIG. 26, the common electrode 9 is formed by a printing method. The material of the common electrode 9 may be formed on one surface of the insulating film 7 by, for example, sputtering, and then the common electrode 9 may be formed by a photolithography method.
Finally, the pressure sensor 1 is completed by bonding the upper electrode member 3 and the lower electrode member 5 via a frame-shaped frame spacer 13 (FIG. 4) made of an adhesive.

2. 2nd Embodiment In the 1st embodiment, the TFT is a top gate type, but the TFT may be a bottom gate type.

Such an embodiment will be described with reference to FIG. FIG. 27 is a partial schematic cross-sectional view of the pressure sensor according to the second embodiment. In this embodiment, only the structure of the TFT is different from that of the fifth embodiment.
As shown in FIG. 27, the source electrode 17A, the drain electrode 19A, and the organic semiconductor 23A are formed on the first insulating film 25A, and the gate electrode 21A is formed on the insulating film 15A.

3. 3. Third Embodiment In each of the first to second embodiments, the pressure-sensitive layer is formed only on the lower electrode member, but the pressure-sensitive layer is formed on both the upper electrode member and the lower electrode member and has a gap between them. May be opposed via.
Such an embodiment will be described with reference to FIG. FIG. 28 is a partial schematic cross-sectional view of the pressure sensor according to the third embodiment. The TFT is a top gate type.

In the upper electrode member 3B, a common pressure sensitive layer 11 is formed on one surface of the common electrode 9. Specifically, the common pressure-sensitive layer 11 is laminated on the surface of the common electrode 9 on the side of the plurality of individual electrodes 31.
In the lower electrode member 5B, the first electrode 31Z, the second electrode 31Y, and the third electrode 31X have a first pressure-sensitive layer 33Z having a large thickness and a second pressure-sensitive layer 33Y having a medium thickness. A small third pressure sensitive layer 33X is formed.

4. Fourth Embodiment In the third embodiment, the TFT is a top gate type, but the TFT may be a bottom gate type.
Such an embodiment will be described with reference to FIG. FIG. 29 is a partial schematic cross-sectional view of the pressure sensor according to the fourth embodiment. In this embodiment, only the structure of the TFT is different from that of the third embodiment.

As shown in FIG. 29, the source electrode 17C, the drain electrode 19C, and the organic semiconductor 23C are formed on the first insulating film 25C, and the gate electrode 21C is formed on the insulating film 15C.

5. Fifth Embodiment In the above embodiment, the number of types of pressure-sensitive layers having different gaps from the common electrode is 3, but it may be 2.
Such an embodiment will be described with reference to FIGS. 30 to 32. FIG. 30 is a schematic diagram for explaining the basic structure of the pressure sensor of the fifth embodiment. FIG. 31 is a schematic cross-sectional view of the pressure sensor. FIG. 32 is a schematic plan view showing the arrangement of individual electrodes.
As shown in FIGS. 30 and 31, in the pressure sensor 1D, the plurality of pressure sensitive layers 33 include a first pressure sensitive layer 33Z for low pressure detection and a second pressure sensitive layer 33Y for medium pressure detection. is doing. That is, unlike the first embodiment, there is no third pressure sensitive layer 33X for detecting high pressure.

The pressure sensor 1D has a pressing region. In the pressing region, it is preferable that the first electrode 31Z and the second electrode 31Y are arranged so as to be included in the minimum pressing area at any pressing location. The first electrode 31Z is for low pressure detection, and the second electrode 31Y is for high pressure detection.
As shown in FIG. 32, the first pressure-sensitive layer 33Z and the second pressure-sensitive layer 33Y are alternately arranged and evenly arranged. Specifically, the first pressure-sensitive layer 33Z and the second pressure-sensitive layer 33Y are arranged so that the same type is diagonally continuous.
In this embodiment, the minimum pressing area is a region of 2 × 2, and when any portion is pressed, at least two first electrodes 31Z and two second electrodes 31Y correspond to each other.
In this embodiment, the first pressure-sensitive layer 33Z has a three-stage configuration and the second pressure-sensitive layer 33Y has a two-stage configuration, but the combination is not limited to this. For example, the first pressure sensitive layer may have a two-stage structure and the first winding pressure layer may have a one-stage structure.

6. Common Matters of the Embodiments The following are common matters of all the above-described embodiments.
As the configuration on the common electrode side, the concept including both the configuration of only the common electrode and the configuration of the combination of the common electrode and the pressure sensitive layer is referred to as a “common conductive layer”.
Using the above concept, a gap is formed between the common conductive layer and the pressure sensitive layer.
In this pressure sensor, when the pressure is low, only the first pressure sensitive layer comes into contact with the common conductive layer. As a result, the resistance change (that is, pressure) of the pressure-sensitive layer can be accurately measured via the first electrode. When the pressure is high, the second pressure-sensitive layer in addition to the first pressure-sensitive layer comes into contact with the common conductive layer. As a result, the resistance change (that is, pressure) of the pressure sensitive layer can be accurately measured via the second electrode. This is because the gap between the second pressure-sensitive layer and the common conductive layer is long, so the pressure measurement range in which electrical resistance can be accurately measured is shifted to the higher pressure side of the first pressure-sensitive layer, that is, high pressure. This is because it corresponds to.

7. Modifications In the first to fifth 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 was connected to one individual electrode.
However, one individual electrode may be associated with a plurality of thin film transistors to detect currents of the plurality of thin film transistors. Specifically, two or more thin film transistors adjacent to one individual electrode are connected. As a result, the detected current value becomes large, and the circuit can be made redundant.
An example of a case where a total of four thin film transistors of 2 × 2 shown in FIG. 8 are associated with one individual 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 four drain electrodes are further short-circuited to connect to one individual electrode via a through hole and a conductive portion.
A plurality of thin film transistor combination patterns are possible, and may be, for example, 2 × 3, 3 × 2, 4 × 4, 5 × 2. Further, there may be a plurality of combination patterns in one pressure device.

8. Other Modifications In the above embodiment, it is assumed that the higher the height of the pressure sensitive layer, the higher the resistance value. That is, if the same pressure-sensitive material is used, the resistance value of the first pressure-sensitive layer 33Z is high, the resistance value of the second pressure-sensitive layer 33Y is medium, and the resistance value of the third pressure-sensitive layer 33X is low.
Measures to solve or alleviate the above problems are described below. It should be noted that FIGS. 33 to 35 used for the explanation are simplified and drawn only by straight lines for easy understanding.
As the first measure, as shown in FIG. 33, the higher the height of the pressure sensitive layer, the wider the pixel electrode, thereby balancing the resistance value for each element. Specifically, the first electrode 31Z has a large area, the second electrode 31Y has a medium area, and the third electrode 31X has a small area.
As a second measure, it is conceivable to form a pressure-sensitive layer from pressure-sensitive materials having different resistance values, and to adopt a pressure-sensitive material having a higher resistance value as the height of the pressure-sensitive layer is higher.
For example, a pressure-sensitive material having a low resistance value is used for the third pressure-sensitive layer 33X, a pressure-sensitive material having a medium resistance value is used for the second pressure-sensitive layer 33Y, and a pressure-sensitive material having a high resistance value is used for the first pressure-sensitive layer 33Z. Is used.

As another example, as shown in FIG. 34, the resistance value difference between the elements is alleviated by forming the plurality of pressure-sensitive layers closer to the pixel electrode with a pressure-sensitive material having a lower resistance value. Specifically, the third pressure-sensitive layer 33X is made of a pressure-sensitive material having a high resistance value, the fourth portion 33D of the second pressure-sensitive layer 33Y is made of a pressure-sensitive material having a high resistance value, and the second pressure-sensitive layer 33Y is made of a pressure-sensitive material. The fifth part 33E is made of a pressure-sensitive material having a medium resistance value, the first part 33A of the first pressure-sensitive layer 33Z is made of a pressure-sensitive material having a high resistance value, and the second part 33B of the first pressure-sensitive layer 33Z is made of a pressure-sensitive material. It is made of a pressure-sensitive material having a medium resistance value, and the third portion 33C of the first pressure-sensitive layer 33Z is made of a pressure-sensitive material having a low resistance value.
As another example, as shown in FIG. 35, the resistance value difference between the elements is alleviated by forming the plurality of pressure-sensitive layers closer to the pixel electrode with a pressure-sensitive material having a higher resistance value. Specifically, the third pressure-sensitive layer 33X is made of a pressure-sensitive material having a high resistance value, the fourth portion 33D of the second pressure-sensitive layer 33Y is made of a pressure-sensitive material having a medium resistance value, and the second pressure-sensitive layer 33Y. The fifth portion 33E of the first pressure-sensitive layer 33Z is made of a pressure-sensitive material having a high resistance value, the first portion 33A of the first pressure-sensitive layer 33Z is made of a pressure-sensitive material having a low resistance value, and the second portion 33B of the first pressure-sensitive layer 33Z is made of a pressure-sensitive material. It is made of a pressure-sensitive material having a medium resistance value, and the third portion 33C of the first pressure-sensitive layer 33Z is made of a pressure-sensitive material having a high resistance value.

9. Other Embodiments Although the 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 gist of the invention. In particular, the plurality of embodiments and modifications described herein can be arbitrarily combined as needed.
In the above embodiment, the insulating film 7 and the insulating film 15 constituting the pressure sensor 1 are rectangular, but the planar shape is not particularly limited as long as they can be mounted along a curved surface. For example, when the pressure sensor is wound into a cylinder and used, it is basically rectangular, and when the cylinder is long like a handrail in a corridor, it is strip-shaped.
In the above embodiment, the individual electrodes 31 and the pressure sensitive layer 33 have a matrix shape in which rows and columns are completely aligned, but they may be arranged in a state of being completely spread out, that is, in a matrix shape in a broad sense.

In the above embodiment, the planar shapes of the individual electrode 31 and the pressure sensitive layer 33 are both circular, but the plane shape is not particularly limited. For example, their planar shapes may be quadrangles, triangles, or other polygons.
In the above embodiment, the plurality of pressure sensitive layers 33 are electrically independent of each other, but the plurality of pressure sensitive layers 33 may be in contact with each other or are continuous with each other.

In the above embodiment, the vertices of the plurality of first pressure sensitive layers 33Z are in contact with the common electrode 9 in the initial state, but a slight gap may be secured between the two in the initial state.
In the above embodiment, the second pressure-sensitive layer 33Y has a constricted portion, but the second pressure-sensitive layer 33Y does not have to have a constricted portion. That is, only the first pressure-sensitive layer 33Z closest to the common electrode may have a constricted portion.
In the above embodiment, the first pressure-sensitive layer 33Z has two constricted portions, but the first pressure-sensitive layer may have one constricted portion. That is, the first pressure sensitive layer may have a two-stage structure.

In the above embodiment, the pressure sensitive layer 33 has a substantially smooth convex shape, but the pressure sensitive layer may have a shape having a flat or concave upper surface.
In the above embodiment, the plurality of steps of the pressure sensitive layer 33 have the same planar shape, but the shape may be different for each step.
In the above embodiment, the centers of the plurality of steps of the pressure sensitive layer 33 are aligned with each other, but the centers of the steps may be offset from each other.
In the above embodiment, the third pressure-sensitive layer 33X does not have a constricted portion, but the third pressure-sensitive layer may also have a constricted portion.

The pressure sensor can be independently used as a flexible sensor that can be attached to another member having a curved surface. Further, the pressure sensor may be a part of a pressure detecting device fixed to a member having a curved surface.
Further, the pressure sensor may be curved so as to form a curved surface in a free state.
The relationship between the timing at which the common electrode or the common pressure-sensitive layer contacts each portion of the first pressure-sensitive layer 33Z and the timing at which the common electrode or the common pressure-sensitive layer contacts each portion of the second pressure-sensitive layer 33Y is not limited to the above-described embodiment. Further, the relationship between the timing at which the common electrode or the common pressure-sensitive layer comes into contact with the third pressure-sensitive layer 33X and the timing of the former two is not limited to the above-described embodiment.

The present invention can be widely applied to a pressure sensor having a pressure sensitive layer and a thin film transistor as a large number of electrodes. In particular, the pressure sensor according to the present invention is used for a member having a curved surface.
Specifically, the pressure sensor is used for the steering wheel of an automobile, and is used for grip position detection, doze detection, and the like. In addition, pressure sensors are used in sporting goods such as golf clubs and baseball bats to measure grip. Further, the pressure sensor is used in a rehabilitation / nursing device, and is used in a handrail, a grip pressure measuring device, and the like. In addition, the pressure sensor is used on the skin surface of the robot.

1: Pressure sensor 3: Upper electrode member 5: Lower electrode member 7: Insulating film 9: Common electrode 11: Common pressure sensitive layer 13: Frame spacer 15: Insulating film 17: Source electrode 19: Drain electrode 21: Gate electrode 23 : Organic semiconductor 25: First insulating film 27: Second insulating film 29: Conductive portion 30: Thin film 31: Individual electrode 31X: Third electrode 31Y: Second electrode 31Z: First electrode 33: Pressure sensitive layer 33A: First Part 33B: 2nd part 33C: 3rd part 33D: 4th part 33E: 5th part 33X: 3rd pressure sensitive layer 33Y: 2nd pressure sensitive layer 33Z: 1st pressure sensitive layer

Claims (14)

A pressure sensor that is used while being mounted along a curved surface.
A common electrode formed over one surface and
A plurality of individual electrodes provided in a matrix facing the common electrode, and
A plurality of thin film transistors provided on the opposite side of the plurality of individual electrodes to the common electrode corresponding to the plurality of individual electrodes, and one or two or more adjacent electrodes are connected to one individual electrode.
A first individual pressure-sensitive layer laminated on the surface of the first electrode of the plurality of individual electrodes on the common electrode side,
A second individual pressure-sensitive layer laminated on the surface of the second electrode of the plurality of individual electrodes on the common electrode side is provided.
The gap between the first individual pressure sensitive layer and the common electrode is shorter than the gap between the second individual pressure sensitive layer and the common electrode.
The first individual pressure-sensitive layer has a larger area than the first portion and the first portion, and is formed under the first portion to form a first constricted portion near the boundary with the first portion. Has two parts,
Pressure sensor. The first individual pressure-sensitive layer has a third portion having a larger area than the second portion and is formed under the second portion to form a second constricted portion in the vicinity of the boundary with the second portion. The pressure sensor according to claim 1. The second individual pressure-sensitive layer has a larger area than the fourth portion and the fourth portion, and is formed under the fourth portion to form a third constricted portion near the boundary with the fourth portion. The pressure sensor according to claim 2, which has five portions. The pressure sensor has a pressing area and has a pressing area.
In the pressing region, the first electrode and the second electrode are dispersedly arranged, so that the minimum pressing area including the first electrode and the second electrode is defined at any pressing location . The pressure sensor according to any one of claims 1 to 3, which is possible. A third individual pressure-sensitive layer laminated on the surface of the third electrode of the plurality of individual electrodes on the common electrode side is further provided.
The pressure sensor according to any one of claims 1 to 4, wherein the gap between the third individual pressure sensitive layer and the common electrode is longer than the gap between the second individual pressure sensitive layer and the common electrode. The pressure sensor according to any one of claims 1 to 5, wherein the area of the first electrode is larger than the area of the second electrode. The pressure sensor according to any one of claims 1 to 5, wherein the pressure-sensitive material of the first individual pressure-sensitive layer has a lower resistance value than the pressure-sensitive material of the second individual pressure-sensitive layer. A pressure sensor that is used while being mounted along a curved surface.
A common electrode formed over one surface and
A plurality of individual electrodes provided in a matrix facing the common electrode, and
A plurality of thin film transistors provided on the opposite side of the plurality of individual electrodes to the common electrode corresponding to the plurality of individual electrodes, and one or two or more adjacent electrodes are connected to one individual electrode.
A common pressure-sensitive layer laminated on the surface of the common electrode on the side of the plurality of individual electrodes,
A first individual pressure-sensitive layer laminated on the surface of the first electrode of the plurality of individual electrodes on the common electrode side,
A second individual pressure-sensitive layer laminated on the surface of the second electrode of the plurality of individual electrodes on the common electrode side is provided.
The gap between the first individual pressure sensitive layer and the common pressure sensitive layer is shorter than the gap between the second individual pressure sensitive layer and the common pressure sensitive layer.
The first individual pressure-sensitive layer has a larger area than the first portion and the first portion, and is formed under the first portion to form a first constricted portion near the boundary with the first portion. Has two parts,
Pressure sensor. The first individual pressure-sensitive layer has a larger area than the second portion and has a third portion formed under the second portion and forming a second constriction portion near the boundary with the second portion. , The pressure sensor according to claim 8. The second individual pressure-sensitive layer has a larger area than the fourth portion and the fourth portion, and is formed under the fourth portion to form a third constricted portion near the boundary with the fourth portion. The pressure sensor according to claim 9, which has five portions. The pressure sensor has a pressing area and has a pressing area.
In the pressing region, the first electrode and the second electrode are dispersedly arranged, so that the minimum pressing area including the first electrode and the second electrode is defined at any pressing location . The pressure sensor according to any one of claims 8 to 10, which is possible. A third individual pressure-sensitive layer laminated on the surface of the third electrode of the plurality of individual electrodes on the common electrode side is further provided.
The gap between the third individual pressure-sensitive layer and the common pressure-sensitive layer is longer than the gap between the second individual pressure-sensitive layer and the common pressure-sensitive layer, according to any one of claims 8 to 11. Pressure sensor. The pressure sensor according to any one of claims 8 to 12, wherein the area of the first electrode is larger than the area of the second electrode. The pressure sensor according to any one of claims 8 to 12, wherein the pressure-sensitive material of the first individual pressure-sensitive layer has a lower resistance value than the pressure-sensitive material of the second individual pressure-sensitive layer.

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