Pressure Sensing Device

Abstract

To provide a pressure detection device with improved reliability capable of detecting pressure applied to a biaxially bent curve surface.SOLUTION: A pressure detection device comprises: a buffer layer made of an elastic material, and comprising a pressing surface including a biaxially bent curve surface and an installation surface composed of a uniaxially bent curve surface facing the pressing surface with a gap therebetween; and a sheet-shaped pressure sensor provided in close contact with the installation surface and uniaxially bent along the installation surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a pressure sensing device. [Background technology]

[0002] A flexible sheet-type pressure sensor has been proposed, which is constructed by mounting a thin-film transistor (TFT) and a pressure-sensitive layer on a polyimide base layer. When such a sheet-type pressure sensor is bent, it can be easily bent if the bending axis is uniaxial, or if there are multiple axes that are parallel to each other. On the other hand, if the bending axes are two axes that are not parallel to each other, it becomes difficult to bend the pressure sensor in two directions. To accommodate biaxial bending, methods have been proposed, such as increasing the elasticity of the pressure sensor itself by using stretchable wiring, or creating notches or holes in a kirigami structure, but both of these methods complicate the manufacturing process and reduce the reliability of the sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-333273 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-90983 [Patent Document 3] Japanese Patent Application Publication No. 2019-95262 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the embodiments of the present invention is to provide a pressure detection device that can detect pressure applied to a biaxially bent curved surface and has improved reliability. [Means for solving the problem]

[0005] The pressure detection device according to the embodiment is made of an elastic material and includes a biaxially bending curved surface.Consists of a convex spherical surface A pressing surface; a flat bottom surface facing the pressing surface, a recess formed in the bottom surface, and a bottom surface of the recess formed by bending the bottom surface of the recess convexly toward the pressing surface; a buffer layer having an installation surface facing the pressing surface at an interval; The recess is accommodated in the a sheet-like pressure sensor that is provided in close contact with the installation surface and bent uniaxially along the installation surface; The pressure sensor is provided with a filling member that fills the recess and blocks the recess, and a controller that is connected to the pressure sensor and detects the position and pressure value of the pressure input to the pressing surface. The controller has a conversion unit that converts the detected pressure value using a function that compresses the pressing surface toward the convex part or a conversion table that compresses the pressing surface toward the convex part. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view of a pressure detection device according to a first embodiment. [Figure 2] 2 is a cross-sectional view of the pressure sensing device taken along line AA in FIG. 1. FIG. [Figure 3] 3 is a cross-sectional view of the pressure sensing device taken along line BB in FIG. 1. [Figure 4] FIG. 4 is a cross-sectional view of a pressure sensor of the pressure detection device. [Figure 5] FIG. 5 is a plan view schematically showing a circuit configuration of the pressure sensor. [Figure 6] FIG. 6 is a cross-sectional view schematically showing a state in which the pressure sensor is pressed. [Figure 7] FIG. 7 is a diagram schematically showing pressure distribution when the center of the pressure detection device is pressed. [Figure 8] FIG. 8 is a diagram schematically showing pressure distribution when the peripheral edge of the pressure detection device is pressed. [Figure 9] FIG. 9 is a diagram showing pressure distributions before and after conversion of the pressure detection device. [Figure 10] FIG. 10 is a cross-sectional view of a pressure sensor according to a modified example. [Figure 11] FIG. 11 is a perspective view showing an example of use of the pressure detection device. [Figure 12] FIG. 12 is a perspective view of a pressure detection device according to a second embodiment. [Figure 13] FIG. 13 is a vertical cross-sectional view of a pressure detection device according to a second embodiment. [Figure 14] FIG. 14 is a perspective view showing an example of use of the pressure detection device according to the second embodiment. [Figure 15]FIG. 15 is a perspective view showing a modified example of the second embodiment. [Figure 16] FIG. 16 is a perspective view showing the pressing surface side of the pressure detection device according to the third embodiment. [Figure 17] FIG. 17 is a perspective view showing the pressure sensor side of the pressure detection device according to the third embodiment. [Figure 18] 18 is a cross-sectional view of the pressure sensing device taken along line DD in FIG. 16. [Figure 19] 19 is a cross-sectional view of the pressure sensing device taken along line EE in FIG. 16. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The disclosure is merely an example, and appropriate modifications that are easily conceivable by those skilled in the art while maintaining the gist of the invention are naturally included within the scope of the present invention. Furthermore, in order to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0008] (First embodiment) The pressure detection device according to the first embodiment will be described in detail. FIG. 1 is a perspective view of a pressure detection device according to a first embodiment, FIG. 2 is a cross-sectional view of the pressure detection device taken along line AA in FIG. 1, and FIG. 3 is a cross-sectional view of the pressure detection device taken along line BB in FIG. In the figure, the first direction X, the second direction Y, and the third direction Z show three directions that are perpendicular to one another, but these directions may intersect at angles other than 90 degrees. The direction toward the tip of the arrow in the third direction Z is defined as up or upward, and the direction opposite to the direction toward the tip of the arrow in the third direction Z is defined as down or downward. The observation position for observing the display device is located at the tip of the arrow in the third direction Z, and viewing from this observation position toward the XY plane defined by the first direction X and the second direction Y is called planar viewing. In the following description, a uniaxially bent surface is defined as a 2D surface bent around a single axis, such as a circular arc, a cylindrical surface, or a triangular pyramid, which becomes a plane when unfolded. A uniaxially bent surface includes a surface bent around multiple parallel axes, such as an S-shaped or wavy surface. A biaxially bent surface is defined as a 3D surface bent around multiple non-parallel axes, such as a spherical surface, a free-form surface, or a barrel-shaped surface.

[0009] As shown in Figures 1 to 3, the pressure detection device 10 according to the first embodiment includes a buffer layer 20 formed of an elastic material such as synthetic resin, rubber, or elastomer, and a sheet-like pressure sensor 50 attached to the buffer layer 20. The buffer layer 20 has a biaxially curved surface, for example, a convex spherical outer surface (pressing surface) SA, and a circular, flat bottom surface SC facing the pressing surface SA. A semi-cylindrical recess 22 having a central axis extending in the first direction X is formed in the center of the bottom surface SC. The bottom surface of the recess 22 forms a uniaxially curved surface, convex toward the pressing surface SA, here a semi-cylindrical installation surface SB. The installation surface SB faces the pressing surface SA at a distance.

[0010] The pressure sensor 50 is formed in a rectangular sheet shape and has a pair of rectangular main surfaces (first main surface and second main surface) facing each other. The pressure sensor 50 is disposed within the recess 22. One of the main surfaces (first main surface) of the pressure sensor 50 is entirely attached to the mounting surface SB of the buffer layer 20 and is in close contact with the entire mounting surface SB. The pressure sensor 50 is uniaxially bent along the mounting surface SB, forming the same uniaxially bent curved surface as the mounting surface SB, in this case a semi-cylindrical shape. A pair of side edges 50a, 50b of the pressure sensor 50 are aligned flush with the bottom surface SC of the buffer layer 20. The recess 22 is filled with a filling member (core material) 24. The core material 24 may be an elastic material, a metal material, or the like that has higher rigidity than the buffer layer 20. The core material 24 is in close contact with the other main surface (second main surface) of the pressure sensor 50 and is provided flush with the bottom surface SC.

[0011] An example of the pressure sensor 50 will be described below. Fig. 4 is a cross-sectional view of the pressure sensor, and Fig. 5 is a plan view showing the circuit configuration of the pressure sensor. As shown in Fig. 4, the sheet-like pressure sensor 50 includes an array substrate 51, a sensor layer (pressure-sensitive layer) 54 facing the array substrate 51 with a gap therebetween, a counter electrode CE laminated in this order on the sensor layer 54, and a protective layer 60. The pressure sensor 50 is formed to have a thickness of about 10 to several hundred µm in the lamination direction. The pressure sensor 50 has a controller 62 connected to the array substrate 51 and the counter electrode CE. The controller 62 measures the pressure value and the pressing position of the pressure applied to the pressure sensor 50.

[0012] The array substrate 51 is a rectangular insulating substrate. The array substrate 51 has a facing surface 51a facing the sensor layer 54 and a bottom surface 51b facing the facing surface 51a. A plurality of array electrodes (pixel electrodes) PE are arranged in a matrix on the facing surface 51a. The bottom surface 51b forms a second main surface of the pressure sensor 50. 5, the array substrate 51 is provided on the opposing surface 51a with a plurality of parallel scanning lines GL, a plurality of signal lines SL extending parallel to each other and perpendicular to the scanning lines GL, and a plurality of transistors TR provided at the intersections of the scanning lines GL and the signal lines SL. A gate electrode GE of the transistor TR is connected to the scanning line GL, and a source electrode SE of the transistor TR is connected to the signal line SL. A drain electrode DE of the transistor TR is connected to an array electrode PE. A sensor layer 54 is disposed between the array electrode PE and the opposing electrode CE.

[0013] As shown in FIG. 4 , the sensor layer 54 is a sheet member formed to have the same shape as the array substrate 51 in a planar view. The sensor layer 54 has a first surface 52a and a second surface 52b opposite the first surface. The sensor layer 54 uses a sensor sheet manufactured separately from the array substrate 51. The sensor layer 54 is formed of a material whose resistance changes when stress is applied, such as a pressure-sensitive conductive elastomer, which is made by dispersing conductive particles in a highly insulating rubber material. In the sensor layer 54, the conductive particles arranged within the base material are spaced apart from each other. The base material of the sensor layer 54 is made of low-rigidity rubber. Therefore, under normal conditions (when not deformed), the sensor layer 54 exhibits very high resistance and is insulating in both the thickness and surface directions. On the other hand, when the sensor layer 54 is pressed from above, the base material at the pressed location recesses toward the array substrate 51. As a result, the conductive particles contained in the deformed base material come into contact with each other, resulting in conductivity in the thickness direction. As described above, the sensor layer 54 is made of a pressure-sensitive material whose resistance value changes when pressure is applied in the thickness direction.

[0014] The first surface 52a of the sensor layer 54 faces the opposing surface 51a of the array substrate 51 and the array electrode PE in a substantially parallel relationship with each other, with a predetermined gap therebetween. A counter electrode CE is laminated on the second surface 52b of the sensor layer 54. The counter electrode CE is a solid electrode formed over the entire surface of the second surface 52b of the sensor layer 54, and is formed in a rectangular shape that is substantially the same size as the array substrate 51 in a plan view. A reference voltage is applied to the counter electrode CE from the controller 62. The protective layer 60 is a sheet member formed in the same shape as the array substrate 51 in a plan view. The protective layer 60 is made of rubber or resin, which has high insulating properties and low rigidity. The protective layer 60 is laminated on the counter electrode CE. The protective layer 60 has a first surface 60a attached to the counter electrode CE and a second surface 60b on the opposite side. The second surface 60b of the protective layer 60 corresponds to the first main surface of the pressure sensor 50 and forms a pressure-receiving surface that receives pressure. The counter electrode CE and the protective layer 60 have the same rigidity as the sensor layer 54, and are designed to recess only in areas pressed by a finger or the like. The counter electrode CE may be formed on the first surface 60a of the protective layer 60, in which case the first surface 60a of the protective layer 60 and the counter electrode CE are attached entirely to the first surface 54a of the sensor layer 54.

[0015] The controller 40 includes a gate driver (not shown) connected to the scanning lines GL and a source driver (not shown) connected to the signal lines SL in order to sequentially select the array electrodes PE. The controller 62 measures the value of the current flowing through the array electrodes PE, and detects the location (coordinates) of the sensor layer 54 that has been deformed by pressure and the pressure (pressure value) based on the measured current value.

[0016] Next, an example of the operation of the pressure sensor 50 will be described. FIG. 6 is a cross-sectional view showing the pressure sensor 50 with the first principal surface (second surface 60b) pressed. When the second surface 60b of the protective layer 60 is not pressed, the thickness of the sensor layer 54 is not reduced anywhere. Therefore, the sensor layer 54 is insulating in the thickness direction, and no current (signal) flows from the counter electrode CE to the sensor layer 54. On the other hand, as shown in FIG. 6, when the second surface 60b of the protective layer 60 is pressed in the thickness direction, the protective layer 60, the counter electrode CE, and the sensor layer 54 are recessed in the pressing direction (stacking direction). As a result, at the pressed location, the first surface 54a of the sensor layer 54 contacts the corresponding array electrode PE (PEa), and the resistance value of the recessed, deformed portion B1 of the sensor layer 54 decreases. Therefore, a current flows from the counter electrode CE to the array electrode PE (PEa) through the deformed portion B1 of the sensor layer 54. In other words, the deformed portion B1 of the sensor layer 54 is not electrically connected to each of the other array electrodes PE positioned around the array electrode PEa in the planar direction. The controller 62 detects that a signal (current) has been input to the array electrode PEa, and calculates the pressed location (coordinates) and pressure value.

[0017] As shown in Figures 2 and 3, the pressure sensor 50 configured as described above is attached to the buffer layer 20 with the second surface 60b (first main surface) of the protective layer 60 in close contact with the mounting surface SB of the buffer layer 20, and is curved along the mounting surface SB, i.e., uniaxially bent. In this embodiment, the elastic material forming the buffer layer 20 has the same degree of rigidity as the protective layer 60 of the pressure sensor 50. In addition, the buffer layer 20 is formed to have a thickness greater than that of the sensor layer 54 of the pressure sensor 50.

[0018] FIG. 7 is a diagram showing a schematic diagram of the pressure distribution when pressing the approximate center of the pressing surface SA of the buffer layer 20 (the part where the buffer layer is thickest), and FIG. 8 is a diagram showing a schematic diagram of the pressure distribution when pressing the peripheral part of the pressing surface SA (the part where the buffer layer is thin). When the pressing surface SA of the buffer layer 20 is a spherical surface (a biaxially bent curved surface) and the pressure receiving surface 60b of the pressure sensor 50 is a semi-cylindrical surface (a uniaxially bent curved surface), the distance between the pressing surface SA and the pressure receiving surface 60b, i.e., the thickness of the buffer layer 20, is not uniform over the entire surface but varies depending on the location. As shown in Figure 7, when pressing the almost center of the pressing surface SA of the buffer layer 20 (the part where the buffer layer is thick), the pressing force (pressure) is slightly blurred and appears large on the pressure sensor 50, that is, the pressure is transmitted to the pressure sensor 50 in a spread state. As shown in FIG. 8, when the peripheral edge of the pressing surface SA (the part where the buffer layer is thin) is pressed obliquely, the pressing force (pressure) is transmitted to the pressure sensor 50 without being blurred, and the pressure sensor 50 recognizes the pressure force as being small.

[0019] Therefore, the controller 62 corrects (converts) the pressure value detected by the pressure sensor 50 in accordance with the biaxial bending curve of the pressing surface SA, thereby correctly detecting the pressure value applied to the pressing surface SA. Figure 9 is a diagram showing a comparison of the pressure distribution before and after conversion of the pressure sensor. In the figure, the solid line shows the pressure distribution before conversion, and the dashed line shows the pressure distribution after conversion. The way in which pressure applied to the spherical surface (pressure surface SA) is reflected on the semi-cylindrical surface (pressure receiving surface 60b) (pressure blur) can be easily calculated as a function using FEM (finite element method) simulation or the like. That is, by using the thickness and shape of the buffer layer 20 as parameters and calculating a function or conversion table that compresses the center of the pressure surface SA more greatly, as shown in FIG. 9, it is possible to create a conversion function or conversion table in advance. In the pressure detection device 10 of this embodiment, an example of the function is as follows:

number

[0020] The pressure sensor 50 is not limited to the above-described embodiment, and various pressure sensors can be applied. Fig. 10 is a cross-sectional view of a pressure sensor according to a modified example. As shown in the figure, according to this modification, a plurality of counter electrodes CE are provided on the first surface 51a of the array substrate 51, and are arranged to face the corresponding array electrodes (pixel electrodes) PE in the planar direction. In this pressure sensor 50, the pressed portions of the protective layer 60 and the sensor layer 54 are recessed toward the array substrate 51, and a portion of the sensor layer 54 comes into contact with the array electrodes PE and the counter electrodes CE, electrically connecting the array electrodes PE and the counter electrodes CE and causing a current to flow through the array electrodes PE. The controller 62 detects that a signal (current) has been input to the array electrode PE and can calculate the pressed portion (coordinates) and pressure value. In addition, the pressure sensor may be a pressure sensor that detects a change in capacitance, a matrix pressure sensor, or the like.

[0021] The pressure detection device 10 configured as described above makes it possible to detect the pressure and pressure distribution applied to a pressing surface having a biaxially bent curved surface using the uniaxially bent pressure sensor 50. There is no need to make the pressure sensor 50 a biaxially bent curved surface, which simplifies the manufacturing process and improves the reliability of the pressure sensor. FIG. 11 is a perspective view showing an example of how the pressure detection device 10 is used. As shown in the figure, in one example, the pressure detection device 10 is installed in a center console box CB of an automobile and forms a touch panel for operating the display DS. The bottom surface SC of the pressure detection device 10 is placed on the center console box CB, and the pressure surface SA side is exposed. When the pressure surface SA is touched, the pressure detection device 10 detects an input operation based on the detected touch position and touch pressure, and controls the display DS accordingly. The pressure detection device 10 can be operated even while wearing gloves, etc. Furthermore, a sheet or plastic exterior may be provided over the pressure surface SA of the buffer layer 20.

[0022] Next, pressure detection devices according to other embodiments will be described. In the other embodiments described below, the same components as those in the first embodiment described above will be assigned the same reference numerals as those in the first embodiment, and detailed descriptions thereof may be omitted or simplified. (Second embodiment) FIG. 12 is a perspective view of a pressure detection device according to the second embodiment, and FIG. 13 is a longitudinal sectional view of the pressure detection device. As shown in the figure, according to the second embodiment, the pressure detection device 10 includes a cylindrical buffer layer 20, a sheet-like pressure sensor 50 attached to the buffer layer 20, and a controller (not shown) connected to the pressure sensor 50. The buffer layer 20 is formed of an elastic material such as synthetic resin, rubber, or elastomer, and has an outer peripheral surface (pressure surface SA) formed by a roughly barrel-shaped, biaxially bent curved surface and an inner peripheral surface (mounting surface SB) formed by a cylindrical, uniaxially bent curved surface. The pressing surface SA and the mounting surface SB have a central axis C1 and are positioned coaxially with each other. The mounting surface SB extends from one end to the other in the axial direction of the buffer layer 20. The mounting surface SB faces the pressing surface SA with a gap therebetween. The gap between the pressing surface SA and the mounting surface SB, i.e., the thickness of the buffer layer 20, is thickest at the center in the axial direction and gradually decreases toward both ends in the axial direction.

[0023] The pressure sensor 50 has the same configuration as the pressure sensor in the first embodiment described above. That is, the pressure sensor 50 is in the form of a rectangular sheet and is formed to a thickness of approximately 10 to several hundred μm. The pressure sensor 50 has a pair of rectangular main surfaces (first main surface and second main surface) facing each other. One main surface (first main surface) of the pressure sensor 50 is entirely attached to the mounting surface SB of the buffer layer 20 and is in close contact with the entire mounting surface SB. The pressure sensor 50 is uniaxially bent along the mounting surface SB to form the same uniaxially bent curved surface as the mounting surface SB, in this case a cylindrical shape. Both axial edges of the pressure sensor 50 are aligned with both axial edges of the mounting surface SB. Note that a cylindrical pressure sensor 50 may also be configured to be attached to the mounting surface SB. The pressure detection device 10 is used in a state where it is attached to a cylindrical or columnar core material that is in close contact with the second main surface of the pressure sensor 50.

[0024] The pressure detection device 10 configured as described above makes it possible to detect the pressure and pressure distribution applied to the pressing surface SA having a biaxially bent curved surface using the uniaxially bent pressure sensor 50. There is no need to bend the pressure sensor 50 biaxially, which simplifies the manufacturing process and improves the reliability of the pressure sensor. FIG. 14 is a perspective view showing an example of how the pressure detection device 10 is used. As shown in the figure, in one example, the pressure detection device 10 is attached to the frame of a walker 70 and forms a grip for the walker 70. The frame is formed, for example, of a cylindrical pipe and is in close contact with the second main surface of the pressure sensor 50. The pressure detection device 10 can measure the gripping force and pressure distribution when the user grips the pressing surface SA. The pressure detection device 10 can measure the gripping force and pressure distribution even when the user is wearing gloves, etc.

[0025] FIG. 15 is a perspective view showing a pressure detection device according to a modified example of the second embodiment. As shown in the figure, the outer peripheral surface (pressure surface SA) of the buffer layer 20 may be a biaxially bent surface that is curved in a substantially bellows shape. The pressure surface SA has a curved shape in which annular protrusions 22a and annular recesses 22b are alternately arranged in the axial direction. The inner peripheral surface (mounting surface SB) of the buffer layer 20 and the sheet-like pressure sensor 50 are formed into a cylindrical uniaxially bent surface. The pressure detection device 10 according to the above modification is suitable for use as a grip for a bicycle, a motorcycle, a walking stick, or the like. In addition, the shape of the biaxially bent curved surface of the pressing surface SA of the buffer layer 20 is not limited to the barrel shape or bellows shape described above, and can be variously modified depending on the purpose of use.

[0026] (Third embodiment) 16 is a perspective view showing the pressing surface side of the pressure detection device of the third embodiment, FIG. 17 is a perspective view showing the pressure sensor side of the pressure detection device of the third embodiment, FIG. 18 is a cross-sectional view of the pressure detection device taken along line DD in FIG. 16, and FIG. 19 is a cross-sectional view of the pressure detection device taken along line EE in FIG. 16. As shown in the figure, the pressure detection device 10 according to the third embodiment includes a flat, substantially rectangular buffer layer 20, a sheet-like pressure sensor 50 attached to the buffer layer 20, and a controller (not shown) connected to the pressure sensor 50. The buffer layer 20 is formed of an elastic material such as synthetic resin, rubber, or elastomer. The buffer layer 20 has an outer surface (pressure surface SA) formed by a biaxially curved surface and an inner surface (installation surface SB) formed by a uniaxially curved, arc-shaped surface. The pressure surface SA is formed into a substantially rectangular shape in a plan view, and forms a convex arc-shaped curved surface in the first direction X and a concave arc-shaped curved surface in the second direction Y. The installation surface SB faces the pressing surface SA with a gap therebetween. The installation surface SB is formed in a rectangular shape in a plan view and forms a concave arc-shaped curved surface with respect to the pressing surface SA. The distance between the pressing surface SA and the installation surface SB, i.e., the thickness of the buffer layer 20, is thinnest in the axial center in the second direction Y and gradually becomes thicker toward both ends in the axial direction. The thickness of the buffer layer 20 is thickest in the axial center in the first direction X and gradually becomes thinner toward both ends in the axial direction.

[0027] The pressure sensor 50 has the same configuration as the pressure sensor in the first embodiment described above. That is, the pressure sensor 50 is in the form of a rectangular sheet and is formed to a thickness of approximately 10 to several hundred μm. The pressure sensor 50 has a pair of rectangular main surfaces facing each other. One of the main surfaces (the second surface 60b of the protective layer described above) of the pressure sensor 50 is entirely attached to the mounting surface SB of the buffer layer 20 and is in close contact with the entire mounting surface SB. The pressure sensor 50 is bent along the mounting surface SB and forms the same uniaxially bent curved surface as the mounting surface SB, in this case a circular arc-shaped curved surface. The four sides of the pressure sensor 50 are aligned with the four sides of the mounting surface SB.

[0028] The pressure detection device 10 configured as described above can be installed on, for example, the seat of a chair, a support stand, a sofa, etc., and can be used as a mat, a cushion, etc. In this case, the pressure sensor 50 side is placed on the seat, support stand, etc. When a user sits on the pressure surface SA, the pressure detection device 10 measures the pressure value and pressure distribution applied to the pressure surface SA. In the pressure detection device 10 according to the third embodiment configured as described above, it is also possible to detect the pressure and pressure distribution applied to the pressing surface SA having a biaxially bent curved surface using the uniaxially bent pressure sensor 50. There is no need to bend the pressure sensor 50 biaxially, which simplifies the manufacturing process and improves the reliability of the pressure sensor.

[0029] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. The embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims. All configurations that can be implemented by a person skilled in the art by appropriately modifying the design based on the respective configurations described above as the embodiments of the present invention also fall within the scope of the present invention as long as they include the gist of the present invention. For example, the shapes of the pressing surface and the installation surface of the buffer layer are not limited to those of the above-described embodiment, and various other shapes can be selected depending on the purpose and usage conditions of the pressure detection device. The constituent materials and dimensions of the buffer layer and the pressure sensor are not limited to those of the above-described embodiment, and can be changed as appropriate. In addition, the bending surface may be a bending surface with two or more axes. [Explanation of symbols]

[0030] 10...pressure detection device, 20...buffer layer, 22...recess, 24...core material, 50...Pressure sensor, 62...Controller, SA...Pressure surface, SB...Installation surface

Claims

1. a buffer layer formed of an elastic material, the buffer layer comprising: a pressing surface formed of a convex spherical surface including a biaxially bent curved surface; a flat bottom surface facing the pressing surface; a recess formed in the bottom surface; and a placement surface forming the bottom surface of the recess, which is uniaxially bent convexly toward the pressing surface, and which faces the pressing surface at an interval; a sheet-like pressure sensor housed in the recess, provided in close contact with the installation surface, and bent uniaxially along the installation surface; a filling member that is filled in the recess and closes the recess; a controller connected to the pressure sensor and configured to detect a position and a pressure value of a pressure input to the pressing surface; the controller has a conversion unit that converts the detected pressure value using a function that compresses the pressure toward a convex portion of the pressing surface or a conversion table that compresses the pressure toward a convex portion of the pressing surface. Pressure sensing device.

2. A buffer layer formed of an elastic material, comprising a pressing surface that is biaxially bent into a barrel shape having a central axis, and an installation surface that is uniaxially bent into a cylindrical shape coaxial with the central axis and has a curved surface that faces the pressing surface at a distance; a sheet-like pressure sensor that is provided in close contact with the installation surface and is uniaxially bent into a cylindrical shape along the installation surface; a controller connected to the pressure sensor and configured to detect a position and a pressure value of a pressure input to the pressing surface; the controller has a conversion unit that converts the detected pressure value using a function that compresses the pressure toward a convex portion of the pressing surface or a conversion table that compresses the pressure toward a convex portion of the pressing surface. Pressure sensing device.

3. A buffer layer formed of an elastic material and including a pressing surface consisting of a biaxially bent curved surface including a concave curved surface, and an installation surface facing the pressing surface at a distance and consisting of a uniaxially bent curved surface that is concave relative to the pressing surface; a sheet-like pressure sensor that is provided in close contact with the installation surface and is uniaxially bent into a concave shape along the installation surface; a controller connected to the pressure sensor and configured to detect a position and a pressure value of a pressure input to the pressing surface; the controller has a conversion unit that converts the detected pressure value using a function that compresses the pressure toward a convex portion of the pressing surface or a conversion table that compresses the pressure toward a convex portion of the pressing surface. Pressure sensing device.

4. 4. The pressure detection device according to claim 1, wherein the pressure sensor comprises an array substrate on which a plurality of array electrodes are provided, a counter electrode facing the array electrodes, a pressure-sensitive layer provided between the array substrate and the counter electrode, and a protective layer formed of an elastic material and provided on top of the counter electrode, the protective layer being attached to the buffer layer in close contact with the installation surface, and the controller being connected to the array substrate and the counter electrode.

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