Pressure-sensitive touch sensor and pressure-sensitive touch sensor module

Abstract

To provide a capacitance type pressure sensitive touch sensor and a pressure sensitive touch sensor module which less likely erroneously detect touch onto an operation surface.SOLUTION: The capacitance type pressure sensitive touch sensor comprises a base material sheet, a protective layer, a first electrode, a second electrode, and an elastic layer. The first electrode and the second electrode are provided on a given surface of the base material sheet. The protective layer is stacked on the surface of the base material sheet where the first electrode and the second electrode are provided so as to cover the first electrode and the second electrode. The base material sheet and the protective layer are folded back between the first electrode and the second electrode, and surfaces of the first electrode and the second electrode face each other. A linear slit is formed along a lengthwise direction of folding lines of the base material sheet and the protective layer on the folding lines. The elastic layer is provided between folding portions of the base material sheet and the protective layer. Pressing force compressively deforms the elastic layer in a thickness direction. Pressing force of the operation surface is detected using a change in capacitance by making distance between the first electrode and the second electrode shorter.SELECTED DRAWING: Figure 2

Description

Technical Field

[0005] , ,

[0001] The present invention relates to a pressure-sensitive touch sensor and a pressure-sensitive touch sensor module. This application claims priority based on Japanese Patent Application No. 2018-102735 filed in Japan on May 29, 2018, the content of which is incorporated herein by reference.

Background Art

[0002] In various fields such as in-vehicle electronic devices, a capacitance-type pressure-sensitive touch sensor module capable of pressure detection has been proposed as a sensor module for detecting operations on an operation surface. For example, in Patent Document 1, a first electrode and a second electrode are provided on one surface of a base material sheet, the base material sheet is partially folded back so that the first electrode and the second electrode face each other, and an elastic sheet is provided between the first electrode and the second electrode A pressure-sensitive touch sensor module is disclosed. In the pressure-sensitive touch sensor module, when the operation surface is pressed, the elastic sheet is compressed and deformed, the first electrode and the second electrode approach each other, the current of the second electrode changes, and the capacitance changes. By detecting this change in capacitance, it is possible to recognize the pressing of the operation surface.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a pressure-sensitive touch sensor module such as that of Patent Document 1, a touch on the operation surface may be erroneously detected and the operation may not be correctly recognized.

[0005] The present invention aims to provide a capacitive pressure-sensitive touch sensor that is less prone to false detection of touches on an operating surface, and a pressure-sensitive touch sensor module equipped with the said pressure-sensitive touch sensor. [Means for solving the problem]

[0006] The present invention has the following configuration. [1] A capacitive pressure-sensitive touch sensor for detecting pressure on an operating surface, It comprises a base sheet, a first electrode, a second electrode, and an elastic layer. The first electrode and the second electrode are provided on any surface of the base sheet. The base sheet is folded back between the first electrode and the second electrode so that the surfaces of the first electrode and the second electrode face each other. A slit is formed in the fold line portion where the base sheet is folded back. The elastic layer is provided between the folded portions of the base sheet. A capacitive pressure-sensitive touch sensor that detects pressure on an operating surface from a change in capacitance caused by the compression deformation of the elastic layer in the thickness direction due to the pressing force, which reduces the distance between the first electrode and the second electrode. [2] The pressure-sensitive touch sensor according to [1], wherein the slit is formed between at least the first electrode and the second electrode in the base sheet. [3] The pressure-sensitive touch sensor according to [1] or [2], wherein the elastic layer is located between the first electrode and the second electrode. [4] The pressure-sensitive touch sensor according to any one of [1] to [3], wherein the elastic layer is a rubber-like elastic body comprising a pair of sheet portions and a column portion sandwiched between the pair of sheet portions. [5] The pressure-sensitive touch sensor according to any one of [1] to [4], wherein the elastic layer is a rubber-like elastic body comprising a pair of sheet portions, a plurality of column portions sandwiched between the pair of sheet portions, and a frame-shaped portion provided so as to surround the plurality of column portions. [6] A pressure-sensitive touch sensor according to any one of [1] to [5], wherein the elastic layer is a rubber-like elastic body comprising a pair of sheet portions, a plurality of column portions sandwiched between the pair of sheet portions, and a ridge or projection portion sandwiched between the pair of sheet portions and lower than the height of the plurality of column portions. [7] A pressure-sensitive touch sensor according to any one of [1] to [5], wherein the elastic layer is a rubber-like elastic body comprising a pair of sheet portions, a plurality of column portions sandwiched between the pair of sheet portions, and protruding portions sandwiched between the pair of sheet portions and arranged in a grid pattern so as to individually surround each of the plurality of column portions. [8] A pressure-sensitive touch sensor according to any one of [1] to [7], wherein a third electrode is further provided on the first surface of the base sheet, and contact of a conductor with the operating surface is detected from the change in capacitance of the third electrode due to contact of a conductor with the operating surface. [9] comprising an operation panel having an operating surface, a frame member, and a pressure-sensitive touch sensor as described in any of [1] to [8], A pressure-sensitive touch sensor module in which the pressure-sensitive touch sensor is sandwiched between the operation panel and the frame member.

[10] The frame member has a protrusion, The pressure-sensitive touch sensor module according to [9], wherein the portion of the pressure-sensitive touch sensor on which the elastic layer is located is sandwiched between the operation panel and the protrusion. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a capacitive pressure-sensitive touch sensor and a pressure-sensitive touch sensor module that are less likely to falsely detect touches on an operating surface. [Brief explanation of the drawing]

[0008] [Figure 1] This is a plan view showing an example of the pressure-sensitive touch sensor of the present invention. [Figure 2] Figure 1 is a cross-sectional view of the pressure-sensitive touch sensor. [Figure 3] Figure 1 is a cross-sectional view of the pressure-sensitive touch sensor's base block (BB). [Figure 4]It is a plan view showing the state before folding back the folded-back portion of the pressure-sensitive touch sensor in FIG. 1. [Figure 5] It is a C-C cross-sectional view of the pressure-sensitive touch sensor in FIG. 4. [Figure 6] It is a plan view showing the state before providing between the folded-back portions of the elastic layer in the pressure-sensitive touch sensor of FIG. 1. [Figure 7] It is a D-D cross-sectional view of the elastic layer in FIG. 6. [Figure 8] It is an exploded perspective view showing an example of the pressure-sensitive touch sensor module of the present invention. [Figure 9] It is a cross-sectional view showing an example of the pressure-sensitive touch sensor module of the present invention. [Figure 10] It is a flowchart showing the flow of processing for recognizing a touch on the operation surface by the pressure-sensitive touch sensor of the present invention. [Figure 11] It is a plan view showing the state before folding back the folded-back portion of another example of the pressure-sensitive touch sensor of the present invention. [Figure 12] It is a cross-sectional view showing the state where the folded-back portion of the pressure-sensitive touch sensor in FIG. 11 is folded back. [Figure 13] It is a cross-sectional view showing the state before providing between the folded-back portions of another example of the elastic layer in the pressure-sensitive touch sensor of the present invention. [Figure 14] It is a plan view showing the state before providing between the folded-back portions of another example of the elastic layer in the pressure-sensitive touch sensor of the present invention. [Figure 15] It is a plan view showing the state before providing between the folded-back portions of another example of the elastic layer in the pressure-sensitive touch sensor of the present invention. [Figure 16] It is an E-E cross-sectional view of the elastic layer in FIG. 15. [Figure 17] It is a plan view showing the state before folding back the folded-back portion of another example of the pressure-sensitive touch sensor of the present invention. [Figure 18] It is a plan view showing the state before folding back the folded-back portion of another example of the pressure-sensitive touch sensor of the present invention. [Figure 19] It is a plan view showing the state before folding back the folded-back portion of another example of the pressure-sensitive touch sensor of the present invention. [Figure 20] This is a plan view showing the state of another example of the pressure-sensitive touch sensor of the present invention before the folded portion is folded. [Figure 21] This is a plan view showing the state of another example of the pressure-sensitive touch sensor of the present invention before the folded portion is folded. [Figure 22] This is a plan view showing the state of another example of the pressure-sensitive touch sensor of the present invention before the folded portion is folded. [Modes for carrying out the invention]

[0009] [Pressure-sensitive touch sensor] The pressure-sensitive touch sensor of the present invention is a capacitive pressure-sensitive touch sensor that detects pressure on an operating surface. An example of the pressure-sensitive touch sensor of the present invention will be described below. The dimensions and other details shown in the following diagrams are merely examples, and the present invention is not necessarily limited to them. It can be modified as appropriate without altering its essence.

[0010] Figure 1 is a plan view showing the pressure-sensitive touch sensor 1 of this embodiment. Figures 2 and 3 are cross-sectional views AA and BB of the pressure-sensitive touch sensor 1 of Figure 1. Figure 4 is a plan view showing the state of the folded portion 1b of the pressure-sensitive touch sensor 1 of this embodiment before it is folded. Figure 5 is a cross-sectional view CC of the pressure-sensitive touch sensor 1 of Figure 4.

[0011] As shown in Figures 1 to 5, the pressure-sensitive touch sensor 1 of this embodiment comprises a base sheet 10, a protective layer 12, an adhesive layer 14, a release paper 16, four first electrodes 18, four second electrodes 20, three third electrodes 22, three auxiliary electrodes 24, and four elastic layers 26.

[0012] The pressure-sensitive touch sensor 1 in this example has a rectangular main body 1a in plan view, four rectangular folded portions 1b in plan view that protrude outward in the width direction from the four corners of the main body 1a, and a strip-shaped portion 1c that extends from the short side of the main body 1a.

[0013] The first surface 10a of the base sheet 10 is provided with a first electrode 18, a second electrode 20, a third electrode 22, and an auxiliary electrode 24, and a protective layer 12 is laminated over them. The protective layer 12 is laminated on the first surface 10a side of the base sheet 10 over the entire body portion 1a, folded portion 1b, and strip-shaped portion 1c of the pressure-sensitive touch sensor 1. On the second surface 10b side of the base sheet 10, a release paper 16 is bonded via an adhesive layer 14. The adhesive layer 14 and release paper 16 are not provided on the folded portion 1b of the pressure-sensitive touch sensor 1, but are provided on the body portion 1a and strip-shaped portion 1c.

[0014] The shape of the base sheet 10 is not limited to the shape shown in this example and can be set as appropriate depending on the application. The dimensions of the base sheet 10 are also not particularly limited and can be set as appropriate depending on the application. A transparent resin insulating film can be used as the base sheet. Here, "transparent" means that the light transmittance measured according to JIS K7136 is 50% or more. Also, "insulating" means that the electrical resistance value is 1 MΩ or more, preferably 10 MΩ or more.

[0015] Examples of materials used to form the base sheet include polyester such as polyethylene terephthalate (PET), polycarbonate (PC), acrylic resin, cyclic polyolefin resin, and triacetylcellulose. The materials used to form the base sheet may be one type or two or more types.

[0016] The average thickness of the base sheet is preferably 10 to 250 μm, and more preferably 25 to 188 μm. If the average thickness of the base sheet is above the lower limit of the above range, sufficient strength and rigidity can be easily ensured. If the average thickness of the base sheet is below the upper limit of the above range, the pressure-sensitive touch sensor can be easily made thinner. In this specification, a numerical range represented by "~" means a numerical range that includes the numbers before and after "~" as the lower and upper limits, respectively.

[0017] The shape and dimensions of the protective layer 12 are not limited to the shape in this example and can be set as appropriate depending on the application. The protective layer is not particularly limited; for example, a transparent resin insulating film, similar to the one mentioned for the base sheet, can be used.

[0018] The average thickness of the protective layer is preferably 10 to 250 μm, and more preferably 10 to 188 μm. If the average thickness of the protective layer is above the lower limit of the above range, sufficient strength and rigidity can be easily ensured. If the average thickness of the protective layer is below the upper limit of the above range, the pressure-sensitive touch sensor can be easily made thinner.

[0019] As shown in Figures 1 and 2, the pressure-sensitive touch sensor 1 has four folded portions 1b that are folded back toward the main body portion 1a. Furthermore, as shown in Figures 1, 2, 4, and 5, a linear slit 28 is formed along the length of the fold line 1d, which is the boundary between the main body portion 1a and the folded portions 1b in the base sheet 10 and the protective layer 12, where the folded portions 1b of the pressure-sensitive touch sensor 1 are folded. As a result, as shown in Figures 1 and 2, the pressure-sensitive touch sensor 1 allows each folded portion 1b to be easily folded back toward the main body portion 1a using the slit 28. In addition, the presence of the slit 28 weakens the force that causes the folded portions 1b to return to their original state before folding.

[0020] In this example, the slits 28 are formed in a continuous solid line shape, but the slits 28 may also be formed in an intermittent dashed line shape. The length of the slit 28 can be set appropriately according to the length of the fold line of the folded portion. The width of the slit 28 can be set as appropriate, for example, 0.5 to 10 mm, preferably 0.5 to 5 mm, and more preferably 1 to 3 mm. If the width of the slit 28 is greater than or equal to the lower limit of the above range, the elastic layer is easier to hold. If the width of the slit 28 is less than or equal to the upper limit of the above range, the product size is less likely to increase.

[0021] As shown in Figure 2, it is preferable that the fold line portion 1d of the pressure-sensitive touch sensor 1 does not have an adhesive layer 14 and a release paper 16. If the fold line portion 1d has an adhesive layer 14 and a release paper 16, when the folded portion 1b is folded back, the force that tries to return the folded portion 1b to its original state tends to be strong due to the influence of the adhesive layer 14 and the release paper 16. By not having an adhesive layer 14 and a release paper 16 on the fold line portion 1d, the force that tries to return the folded portion 1b to its original state is weakened, and the distance between the first electrode 18 and the second electrode 20 becomes stable, so the detection accuracy of the change in capacitance due to pressure is further improved. In addition, it is easier to suppress the breakage of the adhesive layer 14 or damage to the release paper when the folded portion 1b is folded back. Furthermore, when attaching the pressure-sensitive touch sensor 1 to the control panel or during pressing operations, it becomes less likely for unexpected parts of the pressure-sensitive touch sensor 1 to stick to the control panel, thereby suppressing the loss of the resilience of the compressively deformed elastic layer 26.

[0022] The first electrode 18 and the second electrode 20 are pressure-sensitive electrodes for detecting pressure on the operating surface. Each of the first electrode 18 and the second electrode 20 is connected by wiring 2a and 2b to a connection terminal portion 30 formed at the tip of the strip-shaped portion 1c, and is further electrically connected to a capacitance detection unit (not shown) via the connection terminal portion 30.

[0023] In the pressure-sensitive touch sensor 1, a second electrode 20 is provided at each of the four folded portions 1b on the first surface 10a of the base sheet 10. In addition, a first electrode 18 is provided at positions symmetric to the second electrode 20 with respect to the slits 28 at the four corners of the main body portion 1a on the first surface 10a of the base sheet 10. Thus, in this example, slits 28 are formed between the first electrode 18 and the second electrode 20 in the base sheet 10 and the protective layer 12. As shown in Figure 2, when the folded portions 1b are folded towards the main body portion 1a so that the first surface 10a of the base sheet 10 is on the inside, the first electrode 18 and the second electrode 20 overlap when viewed from the thickness direction of the base sheet 10, and their surfaces face each other. Furthermore, the pressure-sensitive touch sensor of the present invention may be configured such that the folded portion 1b of the base sheet 10 is folded inward, with the second surface 10b facing inward.

[0024] In this example, the shapes of the first electrode 18 and the second electrode 20 are rectangular in plan view. However, the shapes of the first electrode 18 and the second electrode 20 are not limited to rectangles and can be designed as appropriate. The dimensions of the first electrode 18 and the second electrode 20 are not particularly limited and can be, for example, approximately 10 mm in length and 10 mm in width. The larger the first electrode 18 and the second electrode 20, the better the sensitivity of detecting the pressing force. In this invention, the size of the electrode furthest from the operating surface may be smaller than that of the electrode closer to the operating surface. For example, in the pressure-sensitive touch sensor 1, the second electrode 20 may be smaller than the first electrode 18. This makes it less likely for the electrode furthest from the operating surface to protrude beyond the electrode closer to the operating surface when viewed from the thickness direction, thus further reducing false detections.

[0025] It is preferable that the first electrode 18 is grounded. This allows the first electrode 18 to act as a shield, suppressing changes in capacitance even when a finger approaches the first electrode 18. This eliminates the influence of the finger approaching the first electrode 18 when attempting to touch the operating surface, and limits the changes to those caused by the pressing force, thereby further suppressing false detection of pressing force.

[0026] The first electrode 18 and the second electrode 20 can be pressure-sensitive electrodes of known nature, and may be self-capacitating or mutually capacitive. One example of a self-capacitance method is a configuration in which both the first electrode 18 and the second electrode 20 are solid electrodes, and the first electrode 18 is grounded. As a mutual capacitance method, for example, one configuration may involve making both the first electrode 18 and the second electrode 20 solid electrodes, and using them as the transmitting electrode and receiving electrode. Alternatively, the first electrode 18 may be a grounded solid electrode, and the second electrode 20 may have the transmitting electrode and receiving electrode arranged in a comb-like pattern.

[0027] The materials for the first electrode 18 and the second electrode 20 are not particularly limited, and electrodes commonly used as pressure-sensitive electrodes can be used. Examples include copper and silver. Depending on the application, indium-doped tin oxide (ITO), conductive polymers, silver nanowires, silver paste, carbon, graphite, carbon nanotubes, etc., may be used as electrode materials. Among these, silver paste is preferred as the electrode material for the first electrode 18 and the second electrode 20. Here, "conductive" means that the electrical resistance is less than 1 MΩ. The average thickness of the first electrode 18 and the second electrode 20 can be set appropriately depending on the material, and the preferred range for the average thickness of the first electrode 18 and the second electrode 20 is the same as the preferred range for the average thickness of the third electrode described later.

[0028] In this example, there are four first electrodes 18 and four second electrodes 20, but the number of first electrodes 18 and second electrodes 20 is not particularly limited. The number of first electrodes 18 may be three or less, or five or more. Similarly, the number of second electrodes 20 may be three or less, or five or more.

[0029] The materials for the wiring 2a and 2b can be the same as those for the first electrode 18 and the second electrode 20, and silver paste is preferred. The preferred range for the average thickness of wiring 2a and 2b is the same as the preferred range for the average thickness of the third electrode described later.

[0030] Furthermore, in the pressure-sensitive touch sensor 1, when the four folded portions 1b are folded, an elastic layer 26 is provided between the main body 1a and each of the folded portions 1b. In this example, when the four folded portions 1b are folded, each elastic layer 26 is positioned between the first electrode 18 and the second electrode 20.

[0031] The elastic layer 26 is a layer containing an elastic material and is compressed and deformed by pressure. When the pressure-sensitive touch sensor 1 is pressed in the thickness direction, the elastic layer 26 is compressed and deformed in the thickness direction, and the capacitance changes as the distance between the first electrode 18 and the second electrode 20 decreases. The pressure on the operating surface is recognized by detecting this change in capacitance.

[0032] Generally, when a base sheet is partially folded, the folded portion tends to unfold and return to its original unfolded state. Therefore, in a pressure-sensitive touch sensor like the one described in Patent Document 1, the force of the folded portion returning to its original state makes it difficult to maintain a constant distance between the first electrode and the second electrode, which is thought to reduce the accuracy of detecting changes in capacitance due to pressure.

[0033] In contrast, in the pressure-sensitive touch sensor 1, as described above, a slit 28 is formed in the fold line 1d where the folded portion 1b of the base sheet 10 and protective layer 12 is folded back. As a result, the force that causes the folded portion 1b to return to its original state is weakened, and the distance between the first electrode 18 and the second electrode 20 is stabilized. Therefore, the accuracy of detecting changes in capacitance due to pressure is improved, and false detection of pressure is suppressed.

[0034] In this invention, as in this example, it is preferable that the slit is formed between at least the first electrode and the second electrode in the base sheet. This reduces the force that causes the folded portion to return to its original state, and the distance between the first electrode 18 and the second electrode 20 becomes more stable, thus further improving the accuracy of pressure detection.

[0035] As shown in Figures 6 and 7, the elastic layer 26 in this example is a rubber-like elastic body comprising a pair of first sheet portions 26a and second sheet portions 26b, and a plurality of column portions 26c sandwiched between the first sheet portion 26a and the second sheet portion 26b. The first sheet portion 26a, the second sheet portion 26b, and the plurality of column portions 26c are integrated together. An elastic member such as a sponge may be placed in the space between the first sheet portion 26a and the second sheet portion 26b, excluding the column portion 26c. This helps to prevent the elastic layer 26 from being excessively compressed and deformed, which could damage the fold line portion 1d of the base sheet 10 or the protective layer 12.

[0036] The materials forming the first sheet portion 26a, the second sheet portion 26b, and the multiple column portions 26c may be the same or different. Of the elastic layer 26, only the column portions 26c that undergo compression deformation need to be made of an elastic material. The first sheet portion 26a and the second sheet portion 26b may be formed of an elastic material or of an inelastic hard material. Examples of hard materials include resins other than elastomers, glass, metals, ceramics, wood, etc.

[0037] As the elastic material forming the elastic body of the elastic layer 26, it is preferable to use one that exhibits an appropriate degree of compressive deformation in the thickness direction due to pressing and has a good pressing feel. Examples of elastic materials include thermosetting elastomers, thermoplastic elastomers, or composites thereof. Examples of thermosetting elastomers include urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, styrene butadiene rubber, and silicone rubber. Examples of thermoplastic elastomers include urethane-based, ester-based, styrene-based, olefin-based, butadiene-based, or fluorine-based elastomers. Among these, silicone rubber is preferred because it exhibits small dimensional changes under repeated pressing, i.e., small compression set. The elastic material may be a foamed material containing internal air bubbles, or a non-foamed material that does not contain substantial air bubbles.

[0038] The Shore A hardness of the elastic body forming the elastic layer 26, measured with a thickness (height) of 1 cm, is preferably 85 or less. If the Shore A hardness is 85 or less, it will easily undergo elastic deformation when pressed. However, if it is too soft, the recovery after elastic deformation will be slow, so the Shore A hardness is preferably 10 or more.

[0039] The average thickness of the first sheet portion 26a is preferably 5 to 100 μm, and more preferably 10 to 100 μm. If the average thickness of the first sheet portion 26a is greater than or equal to the lower limit of the above range, the bonding strength with the column portion 26c can be increased. If the average thickness of the first sheet portion 26a is less than or equal to the upper limit of the above range, the distance between the first electrode 18 and the second electrode 20 when the operating surface is not pressed can be brought closer, and the accuracy of pressure detection can be increased. The preferred range for the average thickness of the second sheet portion 26b is the same as the preferred range for the average thickness of the first sheet portion 26a. The thickness of the first sheet portion 26a and the average thickness of the second sheet portion 26b may be the same or different.

[0040] The shape of the column portion 26c is not particularly limited, and examples include cylindrical, truncated cone, and prismatic shapes. Among these, cylindrical and truncated cone shapes are preferred due to their superior durability. The shapes of the multiple column portions 26c may be the same or different.

[0041] The cross-sectional area of ​​a single column portion 26c in the direction perpendicular to the height direction is not particularly limited, and for example, it can be 0.005 to 4 mm², with 0.02 to 0.8 mm² being preferred. If the cross-sectional area of ​​the column portion 26c is greater than or equal to the lower limit of the range, it becomes easier for it to compress and deform in the height direction when a pressing force is applied, making it easier to prevent the column portion 26c from bending without compression. If the cross-sectional area of ​​the column portion 26c is less than or equal to the upper limit of the range, it can be easily compressed and deformed with a moderate pressing force, such as pressing with a finger. Here, the cross-sectional area of ​​the column refers to the area of ​​the cross-section perpendicular to the height direction at a position half the height of the column. The cross-sectional area of ​​the column can be measured using known microstructure observation methods such as an optical microscope.

[0042] The total cross-sectional area of ​​all columnar portions 26c of the elastic layer 26 can be appropriately set according to the physical properties of the elastic material and the desired pressing feel. When the area of ​​the first sheet portion 26a or the second sheet portion 26b is taken as 100%, the total cross-sectional area is preferably 0.1 to 30%, more preferably 0.5 to 20%, and even more preferably 1 to 10%. If the total cross-sectional area is within the above range, it can be easily compressed and deformed with a moderate pressing force, such as that applied by pressing with a finger. Specifically, for example, the total cross-sectional area can be set to 1 to 100 mm².

[0043] The average height of the column portion 26c is preferably 1 to 3000 μm, more preferably 50 to 2000 μm, even more preferably 200 to 1000 μm, and particularly preferably 300 to 1000 μm. If the average height of the column portion 26c is below the upper limit of the above range, it is easier to bring the distance between the first electrode 18 and the second electrode 20 closer when the operating surface is not pressed, and the accuracy of detecting the pressing force can be improved. In addition, the sensation of the operating surface indenting when pressed is easily suppressed, making it easier to operate with the same feeling as touching a hard surface, like a normal touch panel. Here, the height of the column portion 26c does not include the thickness of the first sheet portion 26a and the thickness of the second sheet portion 26b. The height of the column portion 26c can be measured by known microstructure observation means such as an optical microscope measuring instrument.

[0044] The column section 26c is connected to the first sheet section 26a and the second sheet section 26b, and is a member that supports the thickness of the elastic layer 26. If the thickness of the elastic layer 26 is the same regardless of the location, the heights of the multiple column sections 26c are substantially the same.

[0045] In this example, the arrangement pattern of the multiple column sections 26c in a plan view is such that 25 column sections 26c are arranged in a 5x5 grid with spacing between them in the vertical and horizontal directions within the planar direction of the rectangular first sheet section 26a and second sheet section 26b. However, the arrangement pattern of the multiple column sections 26c is not limited to this pattern; for example, the multiple column sections 26c may be arranged in a staggered pattern.

[0046] The number of columnar portions 26c in the elastic layer 26 may be multiple or one. For example, one rectangular columnar portion 26c may be provided in the central region in the planar direction of the first sheet portion 26a and the second sheet portion 26b. In this configuration, the elastic body forming the columnar portion 26c is preferably a foam containing air bubbles inside.

[0047] The number of columnar portions 26c in the elastic layer 26 is preferably 1 to 1000, more preferably 3 to 100, and even more preferably 4 to 50. If the number is above the lower limit of the range, the elastic layer 26 can be compressed and deformed with a moderate pressing force, such as pressing the operating surface with a finger. If the number is below the upper limit of the range, the detection accuracy of a pressing force such as pressing with a finger can be improved.

[0048] The average pitch between adjacent column portions 26c is preferably 0.1 to 5 mm, and more preferably 0.5 to 3 mm. If the average pitch is above the lower limit of the range, the elastic layer 26 can be compressed and deformed with a moderate pressing force, such as pressing the operating surface with a finger. If the average pitch is below the upper limit of the range, the detection accuracy of a pressing force such as pressing with a finger can be improved.

[0049] As shown in Figure 2, the elastic layer 26 in this example is sandwiched between the first base film 32 and the second base film 34, positioned between the folded portion 1b of the base sheet 10 and the protective layer 12, and bonded to the protective layer 12 via adhesive layers 36 and 38. The elastic layer 26 is bonded to the protective layer 12 by adhesive layers 36 and 38 such that the side edge of the elastic layer 26 on the side of the fold line 1d is closer to the fold line 1d than the side edges of the first electrode 18 and the second electrode 20 on the fold line 1d side. By attaching the elastic layer 26 so that it is closer to the fold line 1d than the first electrode 18 and the second electrode 20, the bending and spreading of the folded portion 1b on the fold line 1d side is suppressed. As a result, the distance between the first electrode 18 and the second electrode 20 becomes stable, and the detection accuracy is improved. Before the folded portion 1b is placed between the folded parts, release paper 40 and 42 are laminated on the surfaces of the adhesive layers 36 and 38, as shown in Figures 6 and 7.

[0050] The adhesive layers 36 and 38 may be provided only on a portion of the adhesion surface between the first base film 32 and the protective layer 12 of the second base film 34, respectively, or they may be provided on the entire adhesion surface. It is preferable that the adhesive layers 36 and 38 be provided on the entire adhesion surface, as this makes it easier to uniformize the pressing force against the elastic layer 26 in the planar direction.

[0051] Examples of materials for the adhesive layers 36 and 38 include, independently, known curing adhesives (liquid adhesives before bonding) or adhesives (pressure-sensitive gel adhesives before bonding). Furthermore, each adhesive layer may be a substrate-type adhesive layer in which adhesive or adhesive is disposed on both sides of the substrate layer. Examples of substrate-type adhesive layers include known double-sided tapes. Examples of adhesives and sealants include acrylic resins, urethane resins, and ethylene-vinyl acetate copolymers. The curing adhesive may be a solvent-type adhesive containing a solvent that volatilizes during curing, or it may be a hot-melt type adhesive.

[0052] The thickness of the adhesive layers 36 and 38 can be independently specified as, for example, 1 to 75 μm. The thickness of the adhesive layers 36 and 38 using the curing type adhesive is preferably 1 to 20 μm. The thickness of the adhesive layers 36 and 38 using the adhesive is preferably 10 to 75 μm.

[0053] As the material for forming the first base film 32 and the second base film 34, insulating resin materials can be used, and examples of each independently include PET, polybutylene terephthalate (PBT), polycarbonate (PC), polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), urethane, etc. The resins forming the first base film 32 and the second base film 34 may be one type or two or more types.

[0054] The average thickness of the first base film 32 and the second base film 34 can be independently, for example, 10 to 200 μm. When using the aforementioned resin material, its thickness is preferably 10 to 200 μm, more preferably 25 to 150 μm, and even more preferably 25 to 100 μm. If the average thickness is above the lower limit of the above range, it is easy to make the pressing force on the elastic layer 26 uniform in the planar direction. If the average thickness is below the upper limit of the above range, the accuracy of detecting input to the operating surface can be improved.

[0055] The first base film 32 and the second base film 34 are bonded to the outer surface of the first sheet portion 26a and the outer surface of the second sheet portion 26b of the elastic layer 26, respectively. These may be bonded by an adhesive layer (not shown), or they may be directly bonded by a known surface treatment or heat treatment. The adhesive surfaces of the first base film 32 and the second base film 34 may be subjected to known physical or chemical surface treatments for the purpose of improving adhesive strength.

[0056] The first base film 32 and the second base film 34 have smooth surfaces relative to the elastic layer 26 so that the pressing force applied to the operating surface is uniformly transmitted to the elastic layer 26. If the first base film 32 and the second base film 34 were not present, the unevenness of the areas where the first electrode 18 and the second electrode 20 are provided may cause uneven pressing against the elastic layer 26. In this embodiment, since the first base film 32 and the second base film 34 are provided, the effect of unevenness in the areas where the first electrode 18 and the second electrode 20 are provided on uneven pressing against the elastic layer 26 can be reduced. In addition, damage to the first electrode 18 and the second electrode 20 due to localized stress from the columnar portion 26c of the elastic layer 26 is suppressed.

[0057] In the pressure-sensitive touch sensor 1, three third electrodes 22 are provided in the center of the first surface 10a of the base sheet 10 in the width direction, spaced apart in the length direction. The third electrodes 22 are touch electrodes for detecting contact of a conductor with the operating surface. In the present invention, it is preferable that, in addition to the first and second electrodes for detecting pressure on the operating surface, a third electrode, which is a touch electrode, is further provided on the first surface of the base sheet. This allows the operation of the operating surface to be determined and recognized in two stages: finger contact and pressure, thereby more reliably suppressing false detections.

[0058] In this example, the shape of the third electrode 22 is rectangular in plan view. However, the shape of the third electrode 22 is not limited to a rectangle and can be designed as appropriate. The dimensions of the third electrode 22 are also not particularly limited and can be, for example, approximately 10 mm in length and 10 mm in width.

[0059] The third electrode 22 may be self-capacitating or mutually capacitive. The third electrode 22 in the mutual capacitance system is not particularly limited and can be, for example, a solid electrode such as a circular, elliptical, or rectangular electrode, a comb-tooth electrode, or a grid electrode pattern or diamond pattern in which a strip-shaped transmitting electrode is formed on one side of the substrate and a plurality of strip-shaped receiving electrodes extending in a direction perpendicular to the transmitting electrode are formed on the other side. The third electrode 22 of the self-capacitance type is not particularly limited and can be, for example, a solid electrode such as a circular, elliptical, or rectangular shape, or a diamond pattern.

[0060] A transparent conductive film can be used as the third electrode 22. Examples of transparent conductive films include films containing conductive polymers, films containing conductive nanowires, films containing metal particles or conductive metal oxide particles, films containing carbon, and metal vapor-deposited films formed by metal vapor deposition. Among transparent conductive films, films containing conductive polymers are preferred in terms of their excellent bending resistance.

[0061] Examples of conductive polymers include polythiophene, polypyrrole, and polyaniline. Among conductive polymers, polythiophene is preferred, and poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonic acid is particularly preferred.

[0062] Examples of conductive nanowires include silver nanowires, gold nanowires, and carbon nanotubes. Examples of metal particles include particles of silver, copper, and gold. Examples of conductive metal oxide particles include indium-doped tin oxide particles. Examples of carbon include carbon black and graphite. Examples of metals used to form the metal vapor-deposited film include copper, aluminum, nickel, chromium, zinc, and gold. Among these, copper is preferred due to its low electrical resistance and low cost.

[0063] The average thickness of the third electrode 22, which is made of a transparent conductive film containing a conductive polymer, is preferably 0.1 to 5.0 μm, and more preferably 0.1 to 2.0 μm. The average thickness of the third electrode 22, which is made of a transparent conductive film containing metal nanowires, is preferably 20 to 1000 nm, and more preferably 50 to 300 nm. The average thickness of the third electrode 22, which is made of metal particles, conductive metal oxide particles, or a transparent conductive film containing carbon, is preferably 0.01 to 25 μm, and more preferably 0.1 to 15 μm. The average thickness of the third electrode 22, which is made of a transparent conductive film of metal deposition, is preferably 0.01 to 1.0 μm, and more preferably 0.05 to 0.3 μm. If the average thickness of the third electrode 22 is greater than or equal to the lower limit of the range, it is easier to suppress wire breakage due to pinholes. If the average thickness of the third electrode 22 is less than or equal to the upper limit of the range, it becomes easier to make it thinner.

[0064] The method for measuring electrode thickness varies depending on the thickness range. For example, for film thicknesses on the order of micrometers, the thickness can be measured using a micrometer, a digital indicator, or laser displacement measurement. For film thicknesses thinner than the order of micrometers, the thickness can be measured using cross-sectional observation with a scanning electron microscope or by an X-ray fluorescence analyzer. The average thickness is the average value of the thickness measured near the center of the electrode.

[0065] In this example, there are three third electrodes 22, but the number of third electrodes 22 is not particularly limited. The number of third electrodes 22 may be two or fewer, or four or more.

[0066] In the pressure-sensitive touch sensor, an auxiliary electrode 24 is provided that surrounds the third electrode 22 and makes full contact with the third electrode 22. The auxiliary electrode 24 is connected by wiring 2c to a connection terminal portion 30 formed at the tip of the strip-shaped portion 1c, and is further electrically connected to a capacitance detection unit (not shown) via the connection terminal portion 30. This allows the third electrode 22 to be connected to the capacitance detection unit. By providing the auxiliary electrode 24, the resistance effect is reduced compared to the case where the third electrode 22 and the wiring 2c are in point contact. Therefore, even when the third electrode 22 is formed from a conductive polymer with relatively high resistance, high detection accuracy can be ensured.

[0067] The material of the auxiliary electrode 24 can be the same as the material of the first electrode 18 and the second electrode 20, and silver paste is preferred. The preferred range for the average thickness of the auxiliary electrode 24 is the same as the preferred range for the average thickness of the third electrode 22.

[0068] The adhesive used to form the adhesive layer 14 is not particularly limited, and examples include the adhesives listed for adhesive layers 36 and 38. The release paper 16 is not particularly limited, and any known release paper can be used.

[0069] The method for manufacturing the pressure-sensitive touch sensor 1 is not particularly limited, and known methods can be used. The first electrode 18, the second electrode 20, the third electrode 22, and the auxiliary electrode 24 can be manufactured, for example, by forming a pattern on the base sheet 10 with electrode material by printing or the like. Alternatively, electrodes may be formed on one or both sides of the base material and then joined to the base sheet 10 with an adhesive or double-sided tape. Examples of methods for forming electrodes include printing a conductive paste and then heating and curing it, printing an ink containing metal particles, and forming a metal foil or metal vapor-deposited film and then patterning it. After forming the first electrode 18, the second electrode 20, the third electrode 22, and the auxiliary electrode 24, a protective layer 12 is laminated to the first surface 10a of the base sheet 10 using an adhesive. Additionally, an adhesive layer 14 is formed by applying an adhesive to the second surface 10b of the base sheet 10.

[0070] The elastic layer 26 can be manufactured, for example, by the following method. Specifically, a second sheet portion 26b is formed on one side of the second base film 34 by screen printing or the like. The surface of the second sheet portion 26b and the surface of each column portion 26c that is in contact with the second sheet portion 26b are irradiated with ultraviolet light, and they are overlapped and pressed to bond the second sheet portion 26b and each column portion 26c. Alternatively, a first sheet portion 26a is formed on one side of the first base film 32 by screen printing or the like. The surface of the first sheet portion 26a and the surface of each column portion 26c that is in contact with the first sheet portion 26a are irradiated with ultraviolet light, and they are overlapped and pressed to bond the first sheet portion 26a and each column portion 26c. This allows the elastic layer 26 to be formed sandwiched between the first base film 32 and the second base film 34.

[0071] The folded portion 1b of the base sheet 10 and the protective layer 12 is folded along the fold line 1d so that the first surface 10a of the base sheet 10 faces inward, and the surfaces of the first electrode 18 and the second electrode 20 face each other. Next, an elastic layer 26 is placed between the folded portions and bonded to the protective layer 12 via adhesive layers 36 and 38. This gives rise to the pressure-sensitive touch sensor 1.

[0072] [Pressure-sensitive touch sensor module] The pressure-sensitive touch sensor module of the present invention comprises an operation panel having an operating surface, a frame member, and the pressure-sensitive touch sensor of the present invention, wherein the pressure-sensitive touch sensor of the present invention is sandwiched between the operation panel and the frame member. Hereinafter, as an example of the pressure-sensitive touch sensor module of the present invention, a pressure-sensitive touch sensor module 100 (hereinafter also referred to as "module 100") equipped with a pressure-sensitive touch sensor 1 will be described with reference to Figures 8 and 9.

[0073] Module 100 comprises an operation panel 110 having an operating surface 112, a frame member 120 having four protrusions 122, and a pressure-sensitive touch sensor 1. The pressure-sensitive touch sensor 1 has a folded portion 1b, with an elastic layer 26 provided between the folded portions, and is sandwiched between the operation panel 110 and the frame member 120. The frame member 120 is provided on the side of the folded portion 1b of the pressure-sensitive touch sensor 1, and the operation panel 110 is provided on the side opposite to the folded portion 1b. In this example, the operation panel 110 and the frame member 120 are connected by a spring 130. The surface of the control panel 110 opposite to the pressure-sensitive touch sensor 1 is the operating surface 112.

[0074] The control panel 110 can be one that has sufficient rigidity to compress an elastic layer located at a distance from the point of pressure when pressed by a finger. However, if the point of pressure and the location of the elastic layer are close together, a panel with lower rigidity may be used as the control panel 110. An example of the control panel 110 is one that comprises a cover layer covering the surface of the pressure-sensitive touch sensor 1 and a decorative layer formed on the surface of the cover layer. The cover layer may also serve as a light guide layer that guides light rays from a light source in a planar direction.

[0075] Examples of materials for the cover layer include glass and resin. Examples of resins include PC, acrylic resin, ABS resin, polystyrene (PS), PVC, PET, PBT, and polyethylene naphthalate (PEN). These resins may be used individually or in combination of two or more types.

[0076] The average thickness of the cover layer is preferably 0.05 mm to 10 mm, and more preferably 2 mm to 5 mm. If the average thickness of the cover layer is above the lower limit of the above range, sufficient strength is easily obtained. If the average thickness of the cover layer is below the upper limit of the above range, it is easier to prevent the module 100 from becoming excessively thick, and when the electrode is touched with a finger, the capacitance of the third electrode changes sufficiently, making it easier to obtain good detection accuracy.

[0077] A decorative layer is a layer to which any decoration is applied, such as ornaments, letters, figures, symbols, patterns, combinations thereof, or combinations of these with colors. A decorative layer can be formed, for example, by printing on the cover layer. The control panel 110 may not have a decorative layer.

[0078] The frame member 120 is provided with four rectangular protrusions 122 on its surface facing the pressure-sensitive touch sensor 1, at positions corresponding to each elastic layer 26 of the pressure-sensitive touch sensor 1 in plan view. When the pressure-sensitive touch sensor 1 is sandwiched between the operation panel 110 and the frame member 120, each of the four protrusions 122 presses against the folded portion 1b where the elastic layer 26 of the pressure-sensitive touch sensor 1 is located. In this way, the portion of the pressure-sensitive touch sensor 1 where the elastic layer 26 is located is sandwiched between the operation panel 110 and the protrusions 122 of the frame member 120.

[0079] The protrusion 122 may be attached to the pressure-sensitive touch sensor 1 with an adhesive. Even when the protrusion 122 is attached to the pressure-sensitive touch sensor 1 with an adhesive, it is preferable that the fold line portion 1d of the folded portion 1b of the pressure-sensitive touch sensor 1 is not provided with adhesive for attaching to the protrusion 122. Specifically, it is preferable that the portion of the fold line portion 1d of the pressure-sensitive touch sensor 1 that does not have a slit 28 is not provided with adhesive. This weakens the force that causes the folded portion 1b of the pressure-sensitive touch sensor 1 to return to its original state.

[0080] In this example, a control board 124 equipped with a capacitance detection unit (IC) is fixed inside the four protrusions 122 on the surface of the frame member 120 on the side facing the pressure-sensitive touch sensor 1. The control board 124 may be connected to the connection terminal portion 30 of the pressure-sensitive touch sensor 1 via a connector (not shown). In addition to the capacitance detection unit (IC), the control board 124 is also equipped with an LED 126 for illuminating characters, which illuminates the characters by passing through the third electrode 22 of the pressure-sensitive touch sensor 1 and the operation panel 110 in accordance with the touch detection state.

[0081] In this invention, it is preferable that the frame member has a protrusion and that the portion of the pressure-sensitive touch sensor where the elastic layer is located is sandwiched between the operation panel and the protrusion of the frame member. This makes the elastic layer 26 more easily compressible and deformable even with just finger pressure, thereby improving the accuracy of touch operation detection.

[0082] Examples of materials used to form the frame members include resin, glass, and inorganic materials. Examples of resins used to form the frame members include the same resins mentioned for forming the cover layer. The resins used to form the frame members may be used individually or in combination of two or more types.

[0083] The following describes the touch operation detection process using module 100, based on Figure 10. In module 100, the four pairs of first electrodes 18 and second electrodes 20 of the pressure-sensitive touch sensor 1 are connected to one capacitance detection unit, and the three third electrodes 22 are each connected to individual capacitance detection units. A first threshold is set for the detection value detected by the capacitance detection unit connected to each third electrode 22, so that when a portion of the operating surface 112 of the operation panel 110 corresponding to a specific third electrode 22 is touched, the detection value corresponding to that third electrode 22 becomes equal to or greater than the first threshold. In addition, a second threshold is set for the detection value detected by the capacitance detection units connected to the four pairs of first electrodes 18 and second electrodes 20, so that when pressed with a predetermined pressing force or greater, the detection value becomes equal to or greater than the second threshold. The four pairs of first electrodes 18 and second electrodes 20 may each be connected to an individual capacitance detection unit. In that case, a second threshold can be set for the sum of the detected values ​​detected by each of the four capacitance detection units.

[0084] In this state, the user presses their finger on the portion of the operating surface 112 of the control panel 110 corresponding to one of the third electrodes 22. First, the capacitance of that third electrode 22 changes, and the detected value in the corresponding capacitance detection unit becomes equal to or greater than the first threshold. Further pressing compresses and deforms the elastic layer 26, bringing the distance between the four pairs of first electrodes 18 and second electrodes 20 closer and changing their capacitance. As a result, the detected value in the capacitance detection unit connected to them becomes equal to or greater than the second threshold. In this case, it is determined that the user has pressed with the intention of operating the device.

[0085] On the other hand, if a finger merely approaches the operating surface 112 of the control panel 110 without touching it, the detected value detected by the capacitance detection unit corresponding to each of the third electrodes 22 will be less than the first threshold, and it will be determined that the device is not touching the device. Furthermore, if the user is merely touching a portion of the operating surface 112 of the control panel 110 corresponding to one third electrode 22, without actually pressing down on that portion, the detected value from the capacitance detection unit corresponding to that third electrode 22 will be above the first threshold, while the detected values ​​from the capacitance detection units corresponding to the four pairs of first electrodes 18 and second electrodes 20 will be below the second threshold. Therefore, if there is no intention to operate the device and the user's finger simply touches the operating surface, it is determined to be a non-touch state. Furthermore, if a portion of the operating surface 112 of the operation panel 110 that does not correspond to the third electrode 22 is pressed, the detected value detected by the capacitance detection unit corresponding to each third electrode 22 will be less than the first threshold, and it will be determined that the device is not in a touch state.

[0086] As described above, in the present invention, slits are formed in the fold line portion of the base sheet of the pressure-sensitive touch sensor to face the first electrode and the second electrode. As a result, the force that tries to return the folded portion of the base sheet to its original state is weak, and the distance between the first electrode and the second electrode is stabilized, thereby suppressing false detection of pressure.

[0087] Furthermore, the pressure-sensitive touch sensor of the present invention is easier to manufacture and more cost-effective compared to a configuration in which the folded portion on which the second electrode is provided is laminated as a separate component, because the base sheet is partially folded back between the first electrode and the second electrode to bring the surfaces of the first and second electrodes facing each other. Furthermore, because the pressure-sensitive touch sensor of the present invention is made of a flexible material, it has good conformability to curved surfaces, high adhesive strength to the control panel, and is less likely to trap air bubbles between the sensor and the control panel.

[0088] Furthermore, in a configuration that combines a first electrode and a second electrode that detect pressure with a third electrode that detects finger contact, that is, a configuration that includes independent pressure-sensitive electrodes and touch electrodes, false detections can be further suppressed because the touch state can be determined using two threshold levels: finger contact and pressure.

[0089] Furthermore, the pressure-sensitive touch sensor and pressure-sensitive touch sensor module of the present invention are not limited to the pressure-sensitive touch sensor 1 described above. For example, as shown in Figures 11 and 12, the pressure-sensitive touch sensor 1A may have the same rectangular main body portion 1a and folded portion 1e, and be folded in half between the main body portion 1a and the folded portion 1e. The same parts in Figures 11 and 12 as in Figures 4 and 2 are denoted by the same reference numerals and their descriptions are omitted. Figure 12 is a cross-sectional view of the portion where the first electrode 18 and the second electrode 20 are located, in the state in which the folded portion 1e of the pressure-sensitive touch sensor 1A of Figure 11 is folded and an elastic layer 26A is provided.

[0090] In the pressure-sensitive touch sensor 1A, the boundary between the main body portion 1a and the folded portion 1e is the fold line portion 1d, and a straight slit 28A is formed along the fold line portion 1d. Furthermore, instead of the four elastic layers 26, one elastic layer 26A is provided between the main body portion 1a and the folded portion 1e. The elastic layer 26A has multiple columnar portions 26c in the parts corresponding to the first electrode 18 and the second electrode 20, and the remaining parts are solid portions 27 with the space filled. By having solid portions 27 in the elastic layer 26A, good light transmittance can be ensured while suppressing the occurrence of steps.

[0091] In the pressure-sensitive touch sensor 1, a step is created at the boundary between the part of the main body 1a where the folded portion 1b exists and the part where the folded portion 1b does not exist. However, in the pressure-sensitive touch sensor 1A, such a step does not occur when the folded portion 1e is folded, which is advantageous because it is less likely for air bubbles to be introduced when attaching it to the control panel, and the attachment work is easier. It is also advantageous because the arrangement of the first electrode 18 and the second electrode 20 can be arranged relatively freely. On the other hand, compared to pressure-sensitive touch sensor 1A, pressure-sensitive touch sensor 1 has a smaller folded portion of the base sheet, and the elastic layer can be made to the minimum necessary size, resulting in lower costs. Furthermore, the portion where the third electrode is provided (the character illumination portion) does not have an elastic layer, resulting in good light transmittance and excellent character visibility.

[0092] Alternatively, instead of the elastic layer 26, a pressure-sensitive touch sensor and pressure-sensitive touch sensor module may be provided with the elastic layer 26B illustrated in Figure 13. Parts in Figure 13 that are the same as those in Figure 7 are denoted by the same reference numerals and their descriptions are omitted. The elastic layer 26B is a rubber-like elastic body comprising a pair of first sheet portions 26a and second sheet portions 26b, a plurality of column portions 26c, and a frame-like portion 26d provided to surround all of the column portions 26c. In the elastic layer 26B, the plurality of column portions 26c and the frame-like portion 26d are sandwiched between the pair of first sheet portions 26a and second sheet portions 26b.

[0093] The force that causes the folded portion 1b to return to its original state is greater the closer it is to the fold line portion 1d. However, by using an elastic layer 26B having a frame-shaped portion 26d, the portion of the elastic layer 26B closer to the fold line portion 1d adheres to the base sheet 10 and the protective layer 12 with higher adhesive strength compared to an elastic layer 26 without a frame-shaped portion 26d. As a result, the distance between the first electrode 18 and the second electrode 20 can be maintained more stably, further improving the accuracy of pressure detection. In addition, the strength against shear forces acting in the planar direction on the elastic layer 26B is also increased.

[0094] Furthermore, as shown in Figure 14, the pressure-sensitive touch sensor and pressure-sensitive touch sensor module may also include an elastic layer 26C in which a partial notch 26e is formed in the frame-shaped portion 26d of the elastic layer 26B. The same parts in Figure 14 as in Figure 13 are denoted by the same reference numerals and their descriptions are omitted. With the elastic layer 26C, air inside the frame-shaped portion 26d can easily escape to the outside during compression deformation, making it easier to compress and deform in the thickness direction compared to the elastic layer 26B.

[0095] Furthermore, as shown in Figures 15 and 16, a pressure-sensitive touch sensor and pressure-sensitive touch sensor module may also be provided with a grid-like elastic layer 26D in which multiple protrusions 26f protruding from the upper surface of the second sheet portion 26b surround multiple column portions 26c. Parts in Figures 15 and 16 that are the same as those in Figures 6 and 7 are denoted by the same reference numerals and their descriptions are omitted. If the elastic layer 26D is used, the protruding portion 26f can suppress excessive compressive deformation of the elastic layer 26D in the thickness direction, making it easy to control the amount of compression. This makes it easier to reduce the compression set of the elastic layer 26D due to excessive compression.

[0096] The height of the protruding section 26f is set to be relatively thinner in proportion to the height of the column section 26c. When the height of the column section 26c is set to 100%, the height of the protruding section 26f is preferably 80% or less. If the degree of indentation of the operating surface is set to be large, for example, it may be 50% or less, or 30% or less. From the viewpoint of reducing the compression set of the column portion 26c, the height of the protruding portion 26f is preferably 10% or more, more preferably 20% or more, even more preferably 30% or more, and particularly preferably 50% or more, relative to 100% of the height of the column portion 26c. From the viewpoint of utilizing the region in the initial stages of compression in which the linearity of the compression properties (compression characteristics) of the column portion 26c is good, the height of the protruding portion 26f is preferably 30% or more, and more preferably 50% or more, relative to 100% of the height of the column portion 26c. The higher the height of the protruding portion 26f, the more effectively the distance between the first electrode and the second electrode can be controlled by utilizing the region in the initial stages of compression of the column portion 26c.

[0097] The height of the protruding section 26f can be set to a range of, for example, 10-80%, 20-70%, 30-60%, 10-50%, 20-50%, or 30-50% of the height of the column section 26c. As a specific example, if the height of the column section 26c exceeds 200 μm, this falls under the relatively high case. If the height of the protruding section 26f is, for example, 80% of the height of the column section 26c (100%), then the movable range (allowable range) for pushing in will exceed 40 μm. A movable range of more than 40 μm is sufficient for pushing in. Here, the height of the protruding portion 26f does not include the thickness of the second sheet portion 26b. The height of the protruding portion 26f can be measured by known microstructure observation means such as an optical microscope measuring instrument.

[0098] The total surface area of ​​the top surfaces (surfaces on the first sheet portion 26a side) of all the protruding portions 26f of the elastic layer 26 is appropriately adjusted to suppress excessive pressing of the column portions 26c. When the area of ​​the first sheet portion 26a or the second sheet portion 26b is set to 100%, the total surface area of ​​the top surfaces of all the protruding portions 26f is preferably 1 to 70%, more preferably 6 to 60%, and even more preferably 8 to 50%. If the ratio is above the lower limit of the range, when the operating surface is pressed in excessively, the top surfaces of the protruding portions 26f in contact with the first sheet portion 26a can resist the pressing force and easily suppress further pressing. If the ratio is below the upper limit of the range, sufficient space can be secured for the installation area of ​​the column portions 26c, which are the main components that determine the elastic force of the elastic layer 26. Furthermore, it is possible to prevent the contact area between the first sheet portion 26a and the protruding portion 26f from becoming excessively large, and to prevent the first sheet portion 26a and the protruding portion 26f from adhering to each other at the contact surface. When the materials constituting the first sheet portion 26a and the protruding portion 26f exhibit tackiness, preventing the above-mentioned adsorption is important from the viewpoint of smoothly performing repeated pressing operations. Specifically, for example, the total surface area of ​​the top surfaces of all the protruding sections 26f can be set to 0.1 to 10 mm².

[0099] In the elastic layer 26, the ratio (S2 / S1) of the total area S2 of the top surfaces of all the protruding portions 26f to the total area S1 of the cross-sections of all the column portions 26c perpendicular to the height direction is preferably 0.1 or more, and more preferably 1 or more. An example of the upper limit of the S2 / S1 ratio is about 50. If S2 / S1 is above the lower limit of the range, when the operating surface is pressed in excessively, the top surfaces of the protruding portions 26f in contact with the first sheet portion 26a can adequately resist the pressing force, and further pressing can be easily suppressed. If S2 / S1 is below the upper limit of the range, a sufficient installation area for the column portions 26c, which are the main components that determine the elastic force of the elastic layer 26, can be secured. In the elastic layer 26, it is preferable that the total area S2 is larger than the total area S1. This relationship allows for sufficient resistance to excessive compression, making it easier to reduce the compression set of the column portion 26c.

[0100] Furthermore, the ridges are not limited to a grid pattern. For example, the elastic layer may have annular ridges lower than the height of the columns, which surround all of the columns on the outside of the elastic layer (the outer edges of a pair of sheet sections) in a plan view. Furthermore, the elastic layer may have multiple columnar sections provided along the outer edge of the elastic layer (the outer edge of a pair of sheet sections) in a plan view, and one or more protrusions lower than the height of the columnar sections provided inside these multiple columnar sections. The preferred configuration of the height of the protrusions and the total area of ​​the top surface on the first sheet section 26a side is the same as the preferred configuration of the ridged sections.

[0101] Furthermore, as shown in Figure 17, the pressure-sensitive touch sensor 1B may also be one in which the first electrode 18A is provided in a frame shape in the main body portion 1a so as to surround the third electrode 22 and the auxiliary electrode 24, and a second electrode 20A having the same shape as the first electrode 18A is provided in the folded portion 1e at a position corresponding to the first electrode 18A. In Figure 17, the same parts as in Figure 11 are denoted by the same reference numerals and their description is omitted.

[0102] The pressure-sensitive touch sensor of the present invention does not necessarily have a third electrode which is a touch electrode. For example, as shown in Figure 18, it may have a main body portion 1a and a folded portion 1f which are folded in half, with a first electrode 18 and a second electrode 20 provided on each of them, and may not have a third electrode 22 and an auxiliary electrode 24. In Figure 18, the same parts as in Figure 4 are denoted by the same reference numerals and their descriptions are omitted.

[0103] The positions of the first and second electrodes in the pressure-sensitive touch sensor of the present invention are not limited to positions such as pressure-sensitive touch sensors 1, 1A to 1C, but can be set as appropriate. Similarly, the position of the third electrode in the pressure-sensitive touch sensor of the present invention is not limited to positions such as pressure-sensitive touch sensors 1, 1A, and 1B, but can be set as appropriate.

[0104] The form of the slit in the pressure-sensitive touch sensor of the present invention is not limited to the slits 28 and 28A described above. The slit may be formed in a portion of the fold line of the pressure-sensitive touch sensor other than the portion of the base sheet between the first electrode and the second electrode. For example, the pressure-sensitive touch sensors 1D to 1G shown in Figures 19 to 22 may be used. Parts in Figures 19 to 22 that are the same as those in Figure 18 are denoted by the same reference numerals and their descriptions are omitted.

[0105] In the pressure-sensitive touch sensor 1D, as shown in Figure 19, a slit 28B is formed extending from one end to the other end of the fold line portion 1d of the main body portion 1a and the folded portion 1f, and the main body portion 1a and the folded portion 1f are connected at one end of the fold line portion 1d. In the pressure-sensitive touch sensor 1E, as shown in Figure 20, slits 28C are formed extending from both ends of the main body portion 1a and the fold line portion 1d of the folded portion 1f toward the center, and the main body portion 1a and the folded portion 1f are connected at the center of the fold line portion 1d.

[0106] In the pressure-sensitive touch sensor 1F, as shown in Figure 21, a slit 28D is formed that extends from one end of the main body portion 1a and the fold line portion 1d of the folded portion 1f toward the other end, and then bends at a right angle toward the folded portion 1f, so that the main body portion 1a and the folded portion 1f are connected at one end of the fold line portion 1d. In the pressure-sensitive touch sensor 1G, as shown in Figure 22, a slit 28E wider than the slit 28C is formed extending from both ends of the main body 1a and the fold line 1d of the folded portion 1f toward the center, and the main body 1a and the folded portion 1f are connected at the center of the fold line 1d.

[0107] The configuration in which the main body portion 1a and the folded portion 1f are connected at both ends of the fold line portion 1d, as in the pressure-sensitive touch sensor 1C, is advantageous compared to the configuration in which they are connected at the center or one end of the fold line portion 1d, as in the pressure-sensitive touch sensors 1D to 1G, in that it is less prone to misalignment when the folded portion 1f is folded and glued together.

[0108] In the configuration of the pressure-sensitive touch sensor 1D, where the main body 1a and the folded portion 1f are connected at one end of the folded line portion 1d, unlike the configuration of the pressure-sensitive touch sensor 1E where they are connected at the center of the folded line portion 1d, the wiring 2b is not placed between the first electrode 18 and the second electrode 20. As a result, the force of the folded portion 1f trying to return to its original state has less influence on the first electrode 18 and the second electrode 20. Therefore, the configuration of the pressure-sensitive touch sensor 1D is preferable to the configuration of the pressure-sensitive touch sensor 1E in that the distance between the first electrode 18 and the second electrode 20 is more stable and the detection accuracy is higher.

[0109] In an embodiment like the pressure-sensitive touch sensor 1F, the rectangular portion of the folded portion 1f where the second electrode 20 is provided and the portion connecting it to one end of the fold line portion 1d, to which the main body portion 1a and the folded portion 1f are connected, are in the shape of a long, narrow strip. As a result, the force that causes the folded portion 1f to return to its original state does not easily affect the second electrode 20. Therefore, an embodiment like the pressure-sensitive touch sensor 1F is preferable to an embodiment like the pressure-sensitive touch sensor 1D in that the distance between the first electrode 18 and the second electrode 20 is more stable and the detection accuracy is higher. In terms of shortening the wiring, an embodiment like the pressure-sensitive touch sensor 1D is preferable to an embodiment like the pressure-sensitive touch sensor 1F.

[0110] An embodiment like pressure-sensitive touch sensor 1G allows for longer distances between the first electrode 18 and the folded portion 1d, and between the second electrode 20 and the folded portion 1d. As a result, the force of the folded portion 1f returning to its original state is less likely to affect the first electrode 18 and the second electrode 20. Therefore, it is preferable in that the distance between the first electrode 18 and the second electrode 20 is more stable, resulting in higher detection accuracy. On the other hand, in terms of making it easier to reduce the product size, embodiments like pressure-sensitive touch sensors 1C to 1F are preferable to embodiments like pressure-sensitive touch sensor 1G. Comparing the pressure-sensitive touch sensors 1C to 1G, pressure-sensitive touch sensors 1C and 1D are preferred over pressure-sensitive touch sensors 1E to 1G, with pressure-sensitive touch sensor 1C being particularly preferred.

[0111] The pressure-sensitive touch sensor of the present invention is not limited to a configuration in which the first electrode and the second electrode are provided on the same surface of a base sheet and the base sheet is folded back so that the surface on which the first electrode and the second electrode are provided is on the inside. For example, the pressure-sensitive touch sensor may be one in which the first electrode and the second electrode are provided on the same surface of a base sheet and the base sheet is folded back so that the surface on which the first electrode and the second electrode are provided is on the outside, so that the surfaces of the first electrode and the second electrode face each other. Furthermore, in the pressure-sensitive touch sensor of the present invention, the first electrode and the second electrode may be provided on different surfaces of the base sheet. For example, the first electrode may be provided on the first surface of the base sheet, the second electrode on the second surface, and the base sheet may be folded so that the surfaces of the first electrode and the second electrode face each other.

[0112] The configuration in which the first electrode and the second electrode are provided on the same surface of the base sheet is advantageous in that it reduces the number of manufacturing steps and lowers costs compared to the configuration in which the first electrode and the second electrode are provided on different surfaces of the base sheet. Furthermore, the configuration in which the first electrode and the second electrode are provided on the same surface of the base sheet and the base sheet is folded back so that the surfaces on which the first electrode and the second electrode are provided face each other is particularly preferable because it allows the distance between the first electrode and the second electrode to be shortened and sensitivity to be higher. [Explanation of Symbols]

[0113] 1...Pressure-sensitive touch sensor, 1a...Main body, 1b...Folded part, 1c...Strip-shaped part, 2a~2c...Wiring, 10...Base sheet, 12...Protective layer, 14...Adhesive layer, 16...Release paper, 18...First electrode, 20...Second electrode, 22...Third electrode, 24...Auxiliary electrode, 26...Elastic layer, 26a...First sheet part, 26b...Second sheet part, 26c...Column part, 28...Slit, 100...Pressure-sensitive touch sensor module, 110...Operation panel, 112...Operation surface, 120...Frame member, 122...Protrusion.

Claims

1. A capacitive pressure-sensitive touch sensor that detects pressure on an operation surface, a base sheet, a protective layer, a first electrode, a second electrode, and an elastic layer; the first electrode and the second electrode are provided on any surface of the base sheet, the protective layer is laminated on the surface of the base sheet on which the first electrode and the second electrode are provided so as to cover the first electrode and the second electrode, the base sheet and the protective layer are folded back between the first electrode and the second electrode, and the surfaces of the first electrode and the second electrode face each other; A linear slit is formed along the length direction of the fold line portion at which the base sheet and the protective layer are folded back, the elastic layer is provided between the base sheet and the folded portion of the protective layer, A capacitive pressure-sensitive touch sensor in which the elastic layer is compressed and deformed in the thickness direction due to pressure, and the pressure on the operating surface is detected from the change in capacitance caused by the distance between the first electrode and the second electrode becoming closer.

2. 2. The pressure-sensitive touch sensor according to claim 1, wherein an adhesive layer for attaching the pressure-sensitive touch sensor to an operation panel is provided on a portion of the base sheet other than the folded portion.

3. The pressure-sensitive touch sensor according to claim 1 , wherein the slit is formed in the base sheet at least between the first electrode and the second electrode.

4. The pressure-sensitive touch sensor of claim 1 , wherein the elastic layer is located between the first electrode and the second electrode.

5. 5. The pressure-sensitive touch sensor according to claim 1, wherein the elastic layer is a rubber-like elastic body having a pair of sheet portions and a column portion sandwiched between the pair of sheet portions.

6. A pressure-sensitive touch sensor as described in any one of claims 1 to 5, wherein the elastic layer is a rubber-like elastic body having a pair of sheet portions, a plurality of pillar portions sandwiched between the pair of sheet portions, and a frame-shaped portion arranged to surround the plurality of pillar portions.

7. A pressure-sensitive touch sensor as described in any one of claims 1 to 6, wherein the elastic layer is a rubber-like elastic body having a pair of sheet portions, a plurality of column portions sandwiched between the pair of sheet portions, and a protrusion or projection portion sandwiched between the pair of sheet portions and lower in height than the plurality of column portions.

8. A pressure-sensitive touch sensor as described in any one of claims 1 to 6, wherein the elastic layer is a rubber-like elastic body having a pair of sheet portions, a plurality of pillar portions sandwiched between the pair of sheet portions, and protrusion portions sandwiched between the pair of sheet portions and arranged in a lattice pattern so as to individually surround each of the plurality of pillar portions.

9. A pressure-sensitive touch sensor according to any one of claims 1 to 8, further comprising a third electrode on the first surface of the base sheet, and detecting contact of a conductor with the operation surface from a change in capacitance of the third electrode due to contact of the conductor with the operation surface.

10. An operation panel having an operation surface, a frame member, and the pressure-sensitive touch sensor according to any one of claims 1 to 9, The pressure-sensitive touch sensor module is configured such that the pressure-sensitive touch sensor is sandwiched between the operation panel and the frame member.

11. the frame member has a protrusion, The pressure-sensitive touch sensor module according to claim 10 , wherein a portion of the pressure-sensitive touch sensor where the elastic layer is located is sandwiched between the operation panel and the convex portion.

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