Pressure-sensitive touch sensor module

Abstract

To provide a pressure-sensitive touch sensor module which has high sensitivity to detect pressing force on an operation surface and has a margin even in an assembly tolerance.SOLUTION: In a pressure-sensitive touch sensor module 1 including an operation panel 10 having an operation surface 10a and a sensor sheet with a first base material sheet 21 provided with a pressure-sensitive sensor part 30, a pressing member 52 is provided at an opposite side to the operation panel 10 of a part with the pressure-sensitive sensor part 30 of the sensor sheet 20, the pressing member 52 and the part with the pressure-sensitive sensor part 30 of the sensor sheet 20 are adhered by an adhesion part 60 made of a hardened material of a liquid adhesive, and an elastic layer 25 provided between a first sensor electrode 23 and a second sensor electrode 24 in the pressure-sensitive sensor part 30 is provided with a peripheral wall part 25d for preventing permeation of the liquid adhesive.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pressure-sensitive touch sensor module. [Background technology]

[0002] Sensor modules that detect operations on an operation surface are used in electronic devices mounted on vehicles, etc. As a sensor module, a capacitive pressure-sensitive touch sensor module capable of detecting pressure when the operation surface is pressed has been proposed. For example, a pressure-sensitive touch sensor module is known in which a sensor sheet having a pressure-sensitive sensor part in which an elastic layer is sandwiched between a pair of electrodes is provided on one side of a base sheet, and the sensor sheet is attached to the side opposite the operation surface of an operation panel (for example, Patent Document 1).

[0003] In such a pressure-sensitive touch sensor module, a pressure member is placed on the opposite side of the pressure sensor unit from the operation panel, so that when the operation surface is pressed, the elastic layer is crushed from both sides in the thickness direction by the operation panel and the pressure member. When the elastic layer is crushed and the distance between the pair of electrodes becomes closer, the capacitance changes, and the pressure can be detected from the change in capacitance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-114208 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in a conventional pressure-sensitive touch sensor module such as that of Patent Document 1, if there is a gap between the pressure-sensitive sensor unit and the pressing member, the elastic layer is not crushed until the gap disappears even when the operation surface is pressed, so the sensitivity of detecting the pressure is low. Also, if the distance between the pressure-sensitive sensor unit and the pressing member is too close and the elastic layer is crushed to a certain extent even when the operation surface is not pressed, the degree of compressive deformation of the elastic layer when the operation surface is pressed is small. In this case, the change in capacitance due to pressing is small, so the sensitivity of detecting the pressure is low. For these reasons, a pressure-sensitive touch sensor module having a mechanism in which the elastic layer is crushed by pressing the operation surface has a problem of strict assembly tolerances.

[0006] An object of the present invention is to provide a pressure-sensitive touch sensor module that has high sensitivity for detecting pressure on an operation surface and has a generous assembly tolerance. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] A pressure-sensitive touch sensor module comprising: an operation panel having an operation surface; a sensor sheet provided on a side of the operation panel opposite the operation surface; and a pressure member, wherein the sensor sheet comprises a base sheet and a pressure-sensitive sensor unit provided on the base sheet, the pressure member being provided on the side of the sensor sheet opposite the operation panel from a portion where the pressure-sensitive sensor unit is provided, the pressure member and the portion of the sensor sheet where the pressure-sensitive sensor unit is provided being adhered to each other by an adhesive made of a hardened liquid adhesive, the pressure-sensitive sensor unit comprising: a first sensor electrode provided on any surface of the base sheet; a second sensor electrode provided on the pressure member side of the first sensor electrode such that the surfaces of the first sensor electrode and the second sensor electrode face each other; and an elastic layer provided between the first sensor electrode and the second sensor electrode, the elastic layer being provided around the entire outer periphery and having a peripheral wall portion that prevents the liquid adhesive from penetrating into the elastic layer. [2] The pressure-sensitive touch sensor module described in [1], wherein the elastic layer is a rubber-like elastic body having the peripheral wall portion, a pair of sheet portions provided on both sides of the peripheral wall portion in the thickness direction, and a plurality of pillar portions provided inside the peripheral wall portion and sandwiched between the pair of sheet portions. [3] The pressure-sensitive touch sensor module described in [1], wherein the elastic layer comprises the peripheral wall portion and a foam filled inside the peripheral wall portion. [4] The pressure-sensitive touch sensor module described in [3], wherein the elastic layer is provided on both sides of the foam in the thickness direction, and further includes upper and lower wall portions that prevent the liquid adhesive from penetrating into the elastic layer. Effect of the Invention

[0008] According to the present invention, it is possible to provide a pressure-sensitive touch sensor module that has high sensitivity for detecting pressure on an operation surface and has a generous assembly tolerance. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a pressure-sensitive touch sensor module according to an embodiment. [Diagram 2] 2 is a plan view of a laminate used in a pressure-sensitive sensor portion of the pressure-sensitive touch sensor module of FIG. 1, viewed from the operation panel side. [Diagram 3] FIG. 11 is a cross-sectional view showing another example of the elastic layer. [Figure 4] FIG. 13 is a cross-sectional view of a pressure-sensitive touch sensor module according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The pressure-sensitive touch sensor module of the present invention is a capacitive pressure-sensitive touch sensor module that detects pressure on an operation surface. An example of the pressure-sensitive touch sensor module of the present invention will be described below. Note that the dimensions of the figures illustrated in the following description are merely examples, and the present invention is not necessarily limited thereto, and can be appropriately modified and implemented without departing from the gist of the present invention.

[0011] Fig. 1 is a cross-sectional view of a pressure-sensitive touch sensor module according to an embodiment of the present invention, Fig. 2 is a plan view of a laminate used in a pressure-sensitive sensor unit of the pressure-sensitive touch sensor module of Fig. 1, viewed from the operation panel side.

[0012] 1, the pressure-sensitive touch sensor module 1 of the embodiment includes an operation panel 10 having an operation surface 10a, a sensor sheet 20 including a pressure-sensitive sensor unit 30, and a pressing member 52. The sensor sheet 20 including the pressure-sensitive sensor unit 30 is provided on the opposite side of the operation panel 10 to the operation surface 10a. The pressing member 52 is provided on a control board 50, and is provided on the opposite side of the operation panel 10 to the portion of the sensor sheet 20 where the pressure-sensitive sensor unit 30 is provided. The pressing member 52 and the portion of the sensor sheet 20 where the pressure-sensitive sensor unit 30 is provided are bonded together by an adhesive 60 made of a cured liquid adhesive.

[0013] An example of the operation panel 10 is a flexible panel. Specifically, when the operation surface 10a of the operation panel 10 is pressed with a finger, the pressed portion locally bends and is pressed in. An example of such an operation panel 10 is a panel made of a resin sheet.

[0014] The material forming the resin sheet may be a transparent material or an opaque material. Here, "transparent" means that the light transmittance measured according to JIS K7136 is 50% or more. Examples of the material forming the resin sheet include resins such as polyester (polyethylene terephthalate (PET) etc.), polycarbonate (PC), acrylic resin, cyclic polyolefin resin, triacetyl cellulose, etc., and elastomers such as silicone rubber. The material forming the resin sheet may be one type only, or two or more types.

[0015] The operation panel 10 may have a single layer structure or a multi-layer structure. The operation panel 10 may be provided with any decoration such as ornaments, characters, figures, symbols, patterns, combinations of these, or combinations of these with colors. For example, a design suggesting the button portion 12 in which the pressure-sensitive sensor unit 30 in the operation panel 10 is located may be formed. Examples of the decorated operation panel 10 include a panel in which a decorative layer is provided on a resin sheet by printing or the like, and a panel made of a resin sheet that is partially or entirely colored.

[0016] The average thickness of the operation panel 10 is preferably 0.1 to 5 mm, and more preferably 0.5 to 1 mm. When the average thickness of the operation panel 10 is equal to or greater than the lower limit of the above range, sufficient mechanical strength is likely to be obtained. When the average thickness of the operation panel 10 is equal to or less than the upper limit of the above range, pressure on the operation panel 10 is easily transmitted to the pressure sensor unit 30 described below, improving pressure detection sensitivity.

[0017] The sensor sheet 20 includes a first base sheet 21, a protective layer 22, a first sensor electrode 23, a second sensor electrode 24, an elastic layer 25, and a second base sheet . A first sensor electrode 23 is provided on a first surface 21a of the first base sheet 21, and a protective layer 22 is laminated so as to cover the first sensor electrode 23. A second surface 21b of the first base sheet 21 is attached to the side opposite the operation surface 10a of the operation panel 10 via an adhesive layer 27. A second sensor electrode 24 is provided on the pressing member 52 side of the first sensor electrode 23 such that the surfaces of the first sensor electrode 23 and the second sensor electrode 24 face each other, and an elastic layer 25 is disposed between the first sensor electrode 23 and the second sensor electrode 24. A second base sheet 26 is provided on the side opposite the elastic layer 25 of the second sensor electrode 24.

[0018] When viewed from the operation surface 10a side of the operation panel 10, the first sensor electrode 23 and the second sensor electrode 24 overlap. The elastic layer 25 is disposed between the first sensor electrode 23 and the second sensor electrode 24 to form the pressure-sensitive sensor section 30. Thus, the sensor sheet 20 includes the first base sheet 21 and the pressure-sensitive sensor section 30 provided on the first base sheet 21. In the pressure-sensitive touch sensor module 1, when the button portion 12 of the operation panel 10 is pressed, a force is applied to the pressure-sensitive sensor section 30 from both sides in the thickness direction by the operation panel 10 and the pressing member 52, and the elastic layer 25 is crushed. As a result, the distance between the first sensor electrode 23 and the second sensor electrode 24 becomes closer, and the capacitance changes, so that the pressing force can be detected.

[0019] The planar shape of the first base sheet 21 is not particularly limited and can be set appropriately depending on the application. The dimensions of the first base sheet 21 are also not particularly limited and can be set appropriately depending on the application. A transparent resin insulating film can be used as the base sheet. "Insulating" means that the electrical resistance is 1 MΩ or more, preferably 10 MΩ or more.

[0020] Examples of materials for forming the first base sheet 21 and the second base sheet 26 include polyester (PET, etc.), PC, acrylic resin, cyclic polyolefin resin, and triacetyl cellulose. The base sheets may be formed of one type of material or two or more types of materials.

[0021] The average thickness of the first base sheet 21 is preferably 10 to 250 μm, and more preferably 25 to 188 μm. When the average thickness of the first base sheet 21 is equal to or greater than the lower limit of the above range, sufficient strength and rigidity can be easily ensured. When the average thickness of the first base sheet 21 is equal to or less than the upper limit of the above range, the sensor sheet 20 can be easily made thin. The preferred range of the average thickness of the second base sheet 26 is the same as the preferred range of the average thickness of the first base sheet 21, for the same reasons as those for the first base sheet 21.

[0022] The protective layer 22 is laminated on the first surface 21a side of the first base sheet 21. The shape and dimensions of the protective layer 22 are not particularly limited and can be appropriately set depending on the application. The protective layer 22 is not particularly limited and can be, for example, the same transparent resin insulating film as that exemplified for the base sheet.

[0023] The average thickness of the protective layer 22 is preferably 10 to 250 μm, and more preferably 10 to 188 μm. When the average thickness of the protective layer 22 is equal to or greater than the lower limit of the above range, sufficient strength and rigidity can be easily ensured. When the average thickness of the protective layer 22 is equal to or less than the upper limit of the above range, the sensor sheet 20 can be easily made thin.

[0024] The first sensor electrode 23 and the second sensor electrode 24 are each connected to a connection terminal (not shown) by wiring, and are further electrically connected to the capacitance detection unit via the connection terminal. In this manner, the first sensor electrode 23 and the second sensor electrode 24 are electrically connected to the capacitance detection unit.

[0025] The planar shape of the first sensor electrode 23 and the second sensor electrode 24 can be appropriately set, for example, a rectangle. The dimensions of the first sensor electrode 23 and the second sensor electrode 24 are not particularly limited, and can be, for example, about 10 mm long x 10 mm wide. The larger the first sensor electrode 23 and the second sensor electrode 24 are, the larger the detection area of ​​the pressing force is. The size of the second sensor electrode 24 may be smaller than the first sensor electrode 23 on the side closer to the operation surface. This makes it difficult for the second sensor electrode 24 to protrude from the first sensor electrode 23 on the side closer to the operation surface 10a when viewed from the operation surface 10a side, making it easier to suppress erroneous detection by the second sensor electrode 24.

[0026] The first sensor electrode 23 may be grounded. This makes it possible to suppress a change in capacitance even if a finger approaches the pressure-sensitive sensor unit 30, because the grounded first sensor electrode 23 acts as a shield. This eliminates the effect of a finger approaching the pressure-sensitive sensor unit 30 when trying to touch the operation surface 10a of the operation panel 10 from the change in capacitance of the first sensor electrode 23 and the second sensor electrode 24, and limits the change to the effect of the pressing force, thereby further suppressing erroneous detection of pressing.

[0027] The first sensor electrode 23 may also serve as a touch sensor electrode for detecting contact of a conductor with the operation surface 10a. This allows the operation of the operation surface 10a to be determined and recognized in two stages, that is, finger contact and pressure, and thus erroneous detection can be more stably suppressed. The touch sensor electrode may be provided on the first base sheet 21 separately from the first sensor electrode 23 and the second sensor electrode 24.

[0028] The first sensor electrode 23 and the second sensor electrode 24 can be pressure-sensitive electrodes of a known type, and may be of a self-capacitance type or a mutual capacitance type. In the case of a self-capacitance type, the first sensor electrode 23 and the second sensor electrode 24 may be configured as a detection electrode that detects a change in capacitance independently, or as one of the electrodes may be a detection electrode and the other may be a GND electrode (a grounded solid electrode). In the case of a mutual capacitance type, the first sensor electrode 23 and the second sensor electrode 24 may be configured as solid electrodes, one of them may be a Tx electrode and the other an Rx electrode, or one of them may be a GND electrode and the other an interdigital electrode in which the Tx electrode and the Rx electrode are arranged in a interdigital shape.

[0029] A preferred embodiment of the first sensor electrode 23 and the second sensor electrode 24 is a self-capacitance type in which the first sensor electrode 23 and the second sensor electrode 24 are detection electrodes that independently detect changes in capacitance. This embodiment makes it easy to distinguish between contact or proximity of a conductor and pressure based on the signals from the first sensor electrode 23 and the second sensor electrode 24, respectively.

[0030] The first sensor electrode 23 and the second sensor electrode 24 are not particularly limited, but are preferably transparent electrodes in order to efficiently illuminate the button portion 12 on which the pressure sensor unit 30 of the operation panel 10 is disposed. A transparent electrode means an electrode having a light transmittance of 50% or more measured according to JIS K7361. For example, a transparent conductive film can be used as the first sensor electrode 23 and the second sensor electrode 24. Here, "conductive" means that the electrical resistance is less than 1 MΩ.

[0031] Examples of transparent conductive films include films containing conductive polymers (such as indium-doped tin oxide (ITO)), films or meshes containing conductive nanowires (such as silver nanowires, gold nanowires, carbon nanotubes), films containing metal particles (such as silver particles, copper particles, gold particles) or conductive metal oxide particles (such as ITO particles), films containing carbon (such as carbon black and graphite), metal vapor deposition films, and metal meshes.

[0032] The average thickness of the first sensor electrode 23 is preferably 0.01 to 25 μm, more preferably 0.1 to 15 μm. The thickness of the second sensor electrode 24 may be appropriately set depending on the material. The average thickness of the electrodes containing conductive polymer is preferably 0.1 to 5.0 μm, more preferably 0.1 to 2.0 μm. The average thickness of the electrodes containing conductive nanowires is preferably 20 to 1000 nm, more preferably 50 to 300 nm. The average thickness of the electrodes containing metal particles, conductive metal oxide particles such as ITO, or carbon is preferably 0.01 to 25 μm, more preferably 0.1 to 15 μm. The average thickness of the electrodes made of a metal vapor deposition film is preferably 0.01 to 1.0 μm, more preferably 0.05 to 0.3 μm. The average thickness of the electrodes made of silver paste or carbon paste is preferably 1 to 25 μm. If the average thickness of the electrodes is equal to or greater than the lower limit of the above range, disconnection due to pinholes is easily suppressed. When the average thickness of the electrodes is equal to or less than the upper limit of the above range, the electrodes can be easily made thinner.

[0033] The method for measuring the thickness of an electrode varies depending on the thickness range. For example, for thicknesses on the order of μm, the thickness can be measured using a micrometer, a digimatic indicator, or a laser displacement measurement. For thicknesses thinner than the order of μm, the thickness can be measured by cross-sectional observation using a scanning electron microscope or by a fluorescent X-ray analyzer. The average thickness is the average value of the thicknesses measured near the center of the electrode when viewed in a plane.

[0034] The arrangement of the first sensor electrodes 23 and the second sensor electrodes 24 in the surface direction of the first base sheet 21 is not particularly limited and can be set appropriately depending on the application. The number of the first sensor electrodes 23 and the second sensor electrodes 24 is also not particularly limited and can be set appropriately depending on the application.

[0035] The material of the wiring connected to the first sensor electrode 23 and the second sensor electrode 24 can be, for example, the same as the material of the first sensor electrode 23 and the second sensor electrode 24, and is preferably silver paste. The preferred range of the average thickness of the wiring is the same as the preferred range of the average thickness of the first sensor electrode 23 and the second sensor electrode 24.

[0036] The elastic layer 25 is a layer including an elastic body, and is compressed and deformed by pressure. When the pressure-sensitive sensor unit 30 is pressed in the thickness direction, the elastic layer 25 is compressed and deformed in the thickness direction, and the distance between the first sensor electrode 23 and the second sensor electrode 24 decreases, causing a change in capacitance. By detecting this change in capacitance, the pressure on the operation surface 10a is recognized.

[0037] As shown in FIG. 1 and FIG. 2, the elastic layer 25 includes a pair of first sheet portions 25a and second sheet portions 25b, a plurality of column portions 25c sandwiched between the first sheet portion 25a and the second sheet portion 25b, and a peripheral wall portion 25d provided on the outer periphery so as to surround the plurality of column portions 25c. The elastic layer 25 is a rubber-like elastic body including the pair of first sheet portions 25a and second sheet portions 25b, the plurality of column portions 25c, and the peripheral wall portion 25d. The elastic layer 25 has a space portion 25e around each of the column portions 25c in the interior surrounded by the pair of first sheet portions 25a and second sheet portions 25b and the peripheral wall portion 25d. Since the elastic layer 25 includes the peripheral wall portion 25d, it is possible to prevent the liquid adhesive for forming the adhesive portion 60 from penetrating into the inside of the elastic layer 25 during manufacturing. The space portion 25e may be filled with a foam such as a sponge.

[0038] The materials forming the first sheet portion 25a, the second sheet portion 25b, the plurality of pillar portions 25c, and the peripheral wall portion 25d may be the same or different. Of the elastic layer 25, the pillar portion 25c and the peripheral wall portion 25d, which are compressively deformed, must be made of an elastic body. The first sheet portion 25a and the second sheet portion 25b may be made of an elastic material, or may be made of a non-elastic hard material. Examples of hard materials include resins other than elastomers, glass, metals, ceramics, and wood.

[0039] The elastic material forming the elastic layer 25 is preferably one that has an appropriate degree of compressive deformation in the thickness direction due to pressing and provides a good pressing feel. Examples of the elastic material include thermosetting elastomers such as urethane rubber, isoprene rubber, ethylene propylene rubber, natural rubber, ethylene propylene diene rubber, styrene butadiene rubber, and silicone rubber; thermoplastic elastomers such as urethane, ester, styrene, olefin, butadiene, and fluorine; and compounds thereof. Among these, silicone rubber is preferable because it is easy to transmit light when illuminating the button portion 12 of the operation panel 10, and has small dimensional changes due to repeated pressing, i.e., small compression set. The peripheral wall portion 25d is made of a non-foamed elastic material so that the liquid adhesive forming the adhesive portion 60 does not soak into the peripheral wall portion 25d. The elastic material forming the portion of the elastic layer 25 other than the peripheral wall portion 25d may be a foam containing air bubbles inside.

[0040] The type A durometer hardness measured according to JIS K 6253 with the thickness (height) of the elastic body forming the elastic layer 25 being 1 cm is preferably 85 or less. If the type A durometer hardness is 85 or less, the elastic layer 25 is easily elastically deformed when pressed. However, if the elastic body is too soft, recovery after elastic deformation is slow, so the type A durometer hardness is preferably 10 or more.

[0041] The average thickness of the first sheet portion 25a is preferably 5 to 100 μm, more preferably 10 to 100 μm. If the average thickness of the first sheet portion 25a is equal to or greater than the lower limit of the range, the bonding strength with the column portion 25c can be increased. If the average thickness of the first sheet portion 25a is equal to or less than the upper limit of the range, the distance between the first sensor electrode 23 and the second sensor electrode 24 can be easily reduced when the operation surface is not being pressed, and the accuracy of detecting the pressing can be increased. The preferred range of the thickness of the second sheet portion 25b is the same as the preferred range of the thickness of the first sheet portion 25a. The thickness of the first sheet portion 25a and the thickness of the second sheet portion 25b may be the same or different.

[0042] The shape of the columnar portion 25c is not particularly limited, and examples thereof include columnar shapes such as a cylindrical shape, a truncated cone shape, and a square column shape. Among these, a cylindrical shape and a truncated cone shape are preferable from the viewpoint of excellent durability. The shapes of the multiple columnar portions 25c may be the same as each other or may be different.

[0043] The average cross-sectional area of ​​a single column portion 25c in a direction perpendicular to the height direction is not particularly limited, and is, for example, 0.005 to 4 mm 2 0.02 to 0.8 mm 2 It is preferable that the average cross-sectional area of ​​the column portion 25c is equal to or greater than the lower limit of the range, it becomes easy to compress and deform in the height direction when a pressing force is applied, and it is easy to prevent the column portion 25c from bending without being compressed. If the average cross-sectional area of ​​the column portion 25c is equal to or less than the upper limit of the range, it can be easily compressed and deformed with a moderate pressing force of about the amount of pressing with a finger. Here, the cross-sectional area of ​​the column portion means the area of ​​a cross section perpendicular to the height direction at a position of 1 / 2 the height of the column portion. The cross-sectional area of ​​the column portion can be measured by a known microstructure observation means such as an optical microscope measuring device.

[0044] The total cross-sectional area of ​​all the pillars 25c of the elastic layer 25 can be appropriately set depending on the properties of the elastic material and the desired pressing comfort. When the area of ​​the first sheet portion 25a or the second sheet portion 25b 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 20%. If the total cross-sectional area is within the above range, it can be easily compressed and deformed with an appropriate pressing force, such as that of a finger. Specifically, for example, the total cross-sectional area can be set to 1 to 100 mm 2 It can be said that:

[0045] The average height of the pillar portion 25c is preferably 1 to 3000 μm, more preferably 50 to 2000 μm, further preferably 200 to 1000 μm, and particularly preferably 300 to 1000 μm. If the average height of the pillar portion 25c is equal to or less than the upper limit of the above range, the distance between the first sensor electrode 23 and the second sensor electrode 24 can be easily reduced when the operation surface is not pressed, and the detection accuracy of the pressing force can be improved. In addition, the feeling that the operation surface is depressed when the operation surface is pressed is easily suppressed, and it is easy to operate with the same feeling as touching a hard surface like a normal touch panel. Here, the height of the pillar portion 25c does not include the thickness of the first sheet portion 25a and the thickness of the second sheet portion 25b. The height of the pillar portion 25c can be measured by a known microstructure observation means such as an optical microscope measuring device. The pillar portion 25c is a member that is connected to the first sheet portion 25a and the second sheet portion 25b and supports the thickness of the elastic layer 25. If the thickness of the elastic layer 25 is the same regardless of the location, the heights of the multiple pillar portions 25c are substantially the same.

[0046] In this example, the arrangement pattern of the multiple pillars 25c in plan view is a pattern in which 25 pillars 25c (5×5) are aligned at intervals in the vertical and horizontal directions in the planar direction of the rectangular first sheet portion 25a and second sheet portion 25b. Note that the arrangement pattern of the multiple pillars 25c is not limited to this pattern, and may be, for example, a pattern in which the multiple pillars 25c are arranged in a staggered pattern.

[0047] The average number of the pillars 25c of the elastic layer 25 is preferably 1 to 1000, more preferably 3 to 100, and further preferably 4 to 50. When the average number is equal to or greater than the lower limit of the range, the elastic layer 25 can be compressed and deformed by a moderate pressure of pressing the operation surface with a finger. When the average number is equal to or less than the upper limit of the range, the detection accuracy of pressing with a finger can be improved. The number of the pillars 25c of the elastic layer 25 may be one. For example, the elastic layer 25 may have one rectangular pillar 25c in plan view in the central region of the first sheet portion 25a and the second sheet portion 25b in the planar direction. In this case, the elastic body forming the pillar 25c is preferably a foam containing air bubbles inside.

[0048] The average pitch between adjacent columns 25c is preferably 0.1 to 6 mm, and more preferably 0.5 to 4 mm. If the average pitch is equal to or greater than the lower limit of the range, the elastic layer 25 can be compressed and deformed by a moderate pressure of pressing the operation surface with a finger. If the average pitch is equal to or less than the upper limit of the range, the detection accuracy of pressing with a finger can be improved.

[0049] If the liquid adhesive forming the adhesive portion 60 hardens while it has entered between the first sheet portion 25a and the second sheet portion 25b, the compressive deformation in the thickness direction is hindered, and the detection sensitivity of the pressing force of the operation surface 10a is reduced. Therefore, it is preferable that the peripheral wall portion 25d is connected to the first sheet portion 25a and the second sheet portion 25b on both sides in the thickness direction so that the liquid adhesive does not enter between the first sheet portion 25a and the second sheet portion 25b. It is also preferable that the peripheral wall portion 25d is provided so that the outer surface of the peripheral wall portion 25d is flush with the outer surfaces of the first sheet portion 25a and the second sheet portion 25b. In this way, if the portion of the peripheral wall portion 25d on the outer surface of the elastic layer 25 is not recessed inward and is flush with the first sheet portion 25a and the second sheet portion 25b, it is easy to suppress the liquid adhesive from hardening in the recessed portion and hindering the compressive deformation of the elastic layer 25.

[0050] The average height of the peripheral wall portion 25d is preferably equal to the average height of the pillar portion 25c. The average thickness of the peripheral wall 25d is preferably 10 to 3000 μm, more preferably 50 to 2000 μm, and even more preferably 100 to 1000 μm. If the average thickness of the peripheral wall 25d is equal to or greater than the lower limit of the above range, leakage due to cracks in the peripheral wall is unlikely to occur. If the average thickness of the peripheral wall 25d is equal to or less than the upper limit of the above range, the effect on the compressive deformation characteristics of the elastic body is minimized.

[0051] 1, the elastic layer 25 in this example is sandwiched between the first base film 31 and the second base film 32, and is disposed between the first sensor electrode 23 and the second sensor electrode 24, and is adhered to the protective layer 22 via an adhesive layer 33. The adhesive layer 33 may be provided only on a part of the contact surface of the first base film 31 with the protective layer 22, or may be provided on the entire contact surface. It is preferable that the adhesive layer 33 is provided on the entire contact surface, since this makes it easy to uniformize the pressing force against the elastic layer 25 in the surface direction.

[0052] Examples of the material of the adhesive layer 33 include a known curing adhesive (liquid adhesive before bonding) or a pressure-sensitive adhesive (gel-like pressure-sensitive adhesive before bonding). The adhesive layer 33 may also be a substrate-type adhesive layer in which an adhesive or pressure-sensitive adhesive is disposed on both sides of a substrate layer. Examples of the substrate-type adhesive layer include a known double-sided tape. Examples of the adhesive or pressure-sensitive adhesive include acrylic resin, urethane resin, and ethylene-vinyl acetate copolymer. The curing adhesive may be a solvent-type adhesive that contains a solvent that volatilizes when cured, or a hot melt type adhesive.

[0053] The thickness of the adhesive layer 33 can be appropriately set, for example, to 1 to 75 μm. The thickness of the adhesive layer 33 using a curable adhesive is preferably 1 to 20 μm. The thickness of the adhesive layer 33 using a pressure-sensitive adhesive is preferably 10 to 75 μm.

[0054] The first base film 31 and the second base film 32 may be made of an insulating resin material, and examples of the resin that can be used independently include PET, polybutylene terephthalate (PBT), PC, polyvinyl chloride (PVC), polymethyl methacrylate (PMMA), and urethane. The first base film 31 and the second base film 32 may be made of one type of resin or two or more types of resin.

[0055] The average thickness of the first base film 31 and the second base film 32 can be independently set to, for example, 10 to 200 μm. When the above-mentioned resin material is used, the average thickness is preferably 10 to 200 μm, more preferably 25 to 150 μm, and even more preferably 25 to 100 μm. When the average thickness is equal to or greater than the lower limit of the above range, it is easy to make the pressing force against the elastic layer 25 uniform in the surface direction. When the average thickness is equal to or less than the upper limit of the above range, it is possible to improve the accuracy of detecting an input to the operation surface 10a.

[0056] The first base film 31 and the second base film 32 are respectively bonded to the outer surface of the first sheet portion 25a and the outer surface of the second sheet portion 25b of the elastic layer 25. They may be bonded by an adhesive layer (not shown), or may be directly bonded by a known surface treatment or heat treatment. The bonding surfaces of the first base film 31 and the second base film 32 may be subjected to a known physical or chemical surface treatment in order to improve the adhesive strength.

[0057] The portion of the sensor sheet 20 where the adhesive layer 27 is provided can be appropriately set within a range in which the sensor sheet 20 can be stably attached to the operation panel 10. The material for forming the adhesive layer 27 is not particularly limited, and examples thereof include the same adhesives and pressure-sensitive adhesives as exemplified for the adhesive layer 33. Among these, a double-sided tape is preferable because the fixing area can be easily controlled.

[0058] In the pressure-sensitive touch sensor module 1, the pressing member 52 and the portion of the sensor sheet 20 where the pressure-sensitive sensor unit 30 is arranged are bonded by an adhesive portion 60 made of a cured liquid adhesive. This fills the gap between the pressing member 52 and the pressure-sensitive sensor unit 30, and the adhesive portion 60 made of a cured product is difficult to deform and easy to transmit force, so when the operation surface 10a is pressed, the force is smoothly transmitted to the elastic layer 25, and the detection sensitivity of the pressure is high. In addition, during manufacturing, the liquid adhesive that forms the adhesive portion 60 before curing easily changes shape. For this reason, even if a certain amount of liquid adhesive is supplied between the pressing member 52 and the pressure-sensitive sensor unit 30 during manufacturing, it can easily follow the proximity of the pressing member 52 and the pressure-sensitive sensor unit 30. Therefore, there is no need to strictly control the distance between the pressing member 52 and the pressure-sensitive sensor unit 30 and the amount of liquid adhesive during manufacturing, and there is a margin for assembly tolerance.

[0059] The liquid adhesive forming the adhesive portion 60 is not particularly limited, and examples thereof include curing adhesives such as epoxy resin-based, urethane resin-based, and silicone resin-based adhesives. Among these, epoxy resin adhesives are preferred in terms of strength and dimensional stability after curing, and little volumetric shrinkage. The liquid adhesive forming the adhesive portion 60 may be one type or two or more types.

[0060] The average thickness of the adhesive portion 60 is preferably 100 to 5000 μm, more preferably 500 to 3000 μm, and even more preferably 1000 to 2000 μm. If the average thickness of the adhesive portion 60 is equal to or greater than the lower limit of the above range, the pressure-sensitive sensor portion and the pressing member can easily come into contact with each other. If the average thickness of the adhesive portion 60 is equal to or less than the upper limit of the above range, the amount of adhesive used and the amount of adhesive not required for contact can be reduced.

[0061] The dimensions and shape of the pressing member 52 may be appropriately set according to the shape of the pressure-sensitive sensor unit 30 so that a sufficient force is applied to the elastic layer 25 when the operation surface 10a is pressed, and may be, for example, a rectangular parallelepiped shape. The material of the pressing member 52 is preferably a non-elastic body because the elastic layer 25 is easily crushed by the operation panel 10 and the pressing member 52 when the operation surface 10a is pressed. Specifically, polycarbonate can be exemplified. The material forming the pressing member 52 may be one type or two or more types.

[0062] There is no particular limitation on the manufacturing method of the pressure-sensitive touch sensor module 1, and any known method can be used. The first sensor electrode 23 and the second sensor electrode 24 can be manufactured, for example, by forming a pattern of an electrode material on the first base sheet 21 and the second base sheet 26 by printing or the like.

[0063] The elastic layer 25 can be manufactured, for example, by the following method. Specifically, the second sheet portion 25b is formed on one side of the second base film 32 by screen printing or the like. The pillar portions 25c and the peripheral wall portion 25d are arranged on the surface of the second sheet portion 25b, and pressure is applied while irradiating ultraviolet rays to bond the second sheet portion 25b to the pillar portions 25c and the peripheral wall portion 25d. The first sheet portion 25a is formed on one side of the first base film 31 by screen printing or the like, and is placed on the pillar portions 25c and the peripheral wall portion 25d, and pressure is applied while irradiating ultraviolet rays to bond the first sheet portion 25a to the pillar portions 25c and the peripheral wall portion 25d. This results in the elastic layer 25 sandwiched between the first base film 31 and the second base film 32.

[0064] For example, protective layer 22 is attached with an adhesive or the like to first surface 21a of first base sheet 21 on which first sensor electrode 23 is formed. Then, first sensor electrode 23 and second sensor electrode 24 are stacked and bonded with an adhesive or the like so that they face each other and elastic layer 25 is disposed therebetween, thereby obtaining sensor sheet 20.

[0065] The method for attaching the sensor sheet 20 to the operation panel 10 is not particularly limited, and examples include a diaphragm method, a roller method, etc. Among them, the diaphragm method is preferable because it is easy to prevent air bubbles from being mixed between the adhesive layer 27 of the sensor sheet 20 and the operation panel 10, and the sensor sheet 20 can be attached more neatly.

[0066] As described above, in the pressure-sensitive touch sensor module 1, the pressing member 52 and the portion of the sensor sheet 20 where the pressure-sensitive sensor unit 30 is arranged are bonded by the adhesive portion 60 made of a hardened liquid adhesive. As a result, there is no gap between the pressing member 52 and the pressure-sensitive sensor unit 30, and the force of pressing the operation surface 10a is smoothly transmitted to the elastic layer 25, so that the detection sensitivity of the pressing force is high. In addition, since the shape of the liquid adhesive before hardening that forms the adhesive portion 60 is easily changed during manufacturing, there is no need to strictly control the distance between the pressing member 52 and the pressure-sensitive sensor unit 30 and the amount of liquid adhesive, and there is a margin for assembly tolerance. In addition, since the elastic layer 25 has the peripheral wall portion 25d, it is possible to prevent the liquid adhesive for forming the adhesive portion 60 from penetrating into the elastic layer 25 and hardening during manufacturing. Therefore, the hardened liquid adhesive is also prevented from hindering the compressive deformation of the elastic layer 25.

[0067] The pressure-sensitive touch sensor module of the present invention is not limited to the pressure-sensitive touch sensor module 1 described above. For example, the pressure-sensitive touch sensor module of the present invention may include an elastic layer 25A as illustrated in FIG. 3 instead of the elastic layer 25. The elastic layer 25A does not include a pillar portion 25c on the inside of the peripheral wall portion 25d of the elastic layer 25, and instead is filled with a foam 25h. The elastic layer 25A further includes an upper wall portion 25f and a lower wall portion 25g provided on both sides of the foam 25h in the thickness direction.

[0068] Elastic layer 25A also has peripheral wall 25d, which can prevent liquid adhesive for forming adhesive portion 60 from penetrating into elastic layer 25 from the periphery and curing during manufacturing. In addition, upper wall 25f and lower wall 25g are provided on both sides of foam 25h in the thickness direction in elastic layer 25A, which can more stably prevent liquid adhesive for forming adhesive portion 60 from penetrating into elastic layer 25 and curing during manufacturing. The pressure-sensitive touch sensor module of the present invention may include an elastic layer 25A that does not include at least one of the upper wall portion 25f and the lower wall portion 25g.

[0069] The pressure-sensitive touch sensor module of the present invention may be the pressure-sensitive touch sensor module 2 exemplified in FIG. 4. The pressure-sensitive touch sensor module 2 is similar to the pressure-sensitive touch sensor module 1, except that a sensor sheet 20A is provided instead of the sensor sheet 20. The sensor sheet 20A is similar to the sensor sheet 20, except that a first sensor electrode 23 and a second sensor electrode 24 are provided on a first surface 21a of a first base sheet 21, and the first base sheet 21 is partially folded back to make the first sensor electrode 23 and the second sensor electrode 24 face each other. The pressure-sensitive touch sensor module 2 also has the same effects as the pressure-sensitive touch sensor module 1.

[0070] The pressure-sensitive touch sensor module of the present invention may be a pressure-sensitive touch sensor module in which the first sensor electrode 23 is provided on the second surface 21b of the first base sheet 21. Furthermore, within the scope of the present invention, the components in the above-described embodiments may be replaced with well-known components, and the above-described modified examples may be combined as appropriate. [Explanation of symbols]

[0071] 1,2...pressure-sensitive touch sensor module, 10...operation panel, 10a...operation surface, 20...sensor sheet, 21...first base sheet, 22...protective layer, 23...first sensor electrode, 24...second sensor electrode, 25,25A...elastic layer, 25a...first sheet portion, 25b...second sheet portion, 25c...column portion, 25d...peripheral wall portion, 25e...space portion, 25f...upper wall portion, 25g...lower wall portion, 25h...foam, 26...second base sheet, 30...pressure-sensitive sensor portion, 52...pressure member, 60...adhesive portion.

Claims

1. The device includes an operation panel having an operation surface, a sensor sheet provided on a side of the operation panel opposite to the operation surface, and a pressing member, The sensor sheet includes a first base sheet, a pressure-sensitive sensor unit provided on the first base sheet, and a second base sheet, the pressing member is provided on a side of the sensor sheet opposite to the operation panel with respect to a portion on which the pressure-sensitive sensor unit is disposed, the pressure member and the portion of the sensor sheet in which the pressure-sensitive sensor unit is disposed are bonded to each other by an adhesive portion made of a cured liquid adhesive, the pressure-sensitive sensor unit includes a first sensor electrode provided on an arbitrary surface of the first base sheet, a second sensor electrode provided on the pressing member side of the first sensor electrode such that the first sensor electrode and the second sensor electrode face each other, and an elastic layer provided between the first sensor electrode and the second sensor electrode, the second base sheet is provided on a side of the second sensor electrode opposite to the elastic layer, the elastic layer is a rubber-like elastic body including a peripheral wall portion that prevents the liquid adhesive from penetrating into the elastic layer, a pair of sheet portions provided on both sides of the peripheral wall portion in a thickness direction, and a plurality of column portions sandwiched between the pair of sheet portions, The peripheral wall portion is provided around the entire outer periphery so as to surround the multiple pillar portions, in this pressure-sensitive touch sensor module.

2. The pressure-sensitive touch sensor module of claim 1 , wherein the elastic layer comprises the peripheral wall and a foam filled inside the peripheral wall.

3. 3. The pressure-sensitive touch sensor module of claim 2, wherein the elastic layer is provided on both sides of the foam in the thickness direction, and further includes upper and lower wall portions that prevent the liquid adhesive from penetrating into the interior of the elastic layer.

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