Touch-type input device

Abstract

This touch-type input device comprises: a housing having a first surface and a second surface on opposite sides from each other; a plurality of pressure-sensitive elements each having a rectangular shape in plan view; and a plurality of adhesive members. The polarity of the output of each of the plurality of pressure-sensitive elements differs between when extended in a first direction in which one side of the pressure-sensitive element extends and when being compressed in the first direction. The first surface has a plurality of operation regions. The second surface has a plurality of detection regions positioned overlapping the plurality of operation regions in plan view. The plurality of pressure-sensitive elements are respectively adhered to the plurality of detection regions by the plurality of adhesive members so as to be positioned at the centers of the plurality of detection regions. The plurality of pressure-sensitive elements are disposed such that the first direction of the plurality of pressure-sensitive elements and the direction in which the plurality of operation regions are aligned are substantially parallel to each other.

Description

Touch Input Device

[0001] The present invention relates to a touch input device that detects an input operation by an operator.

[0002] A known example of a conventional invention related to a touch input device is the touch input device described in Patent Document 1. The touch input device described in Patent Document 1 includes a housing, a plurality of piezoelectric elements, and an adhesive member that adheres the plurality of piezoelectric elements to the rear surface of the housing. When the surface of the housing is pressed, the piezoelectric elements arranged at the pressed position expand and generate an electric charge. In this way, the touch input device described in Patent Document 1 detects an operation input due to pressing and the operation input position.

[0003] Patent No. 6156587

[0004] When multiple piezoelectric elements are attached to the back surface of the housing with a single adhesive member, deformation of the housing is transmitted to the multiple piezoelectric elements via the adhesive member regardless of the position of pressure on the housing. Therefore, even if an area where no piezoelectric elements are located is pressed, electric charges are generated due to the expansion and contraction of the piezoelectric elements, and there is a risk that the operation input position cannot be accurately detected.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a touch-type input device that can more accurately detect an operation input position by pressing.

[0006] A touch-type input device according to one embodiment of the present invention comprises a housing having opposing first and second surfaces; a plurality of pressure-sensitive elements each having a rectangular shape in a planar view; and a plurality of adhesive members, wherein the polarity of the output of each of the plurality of pressure-sensitive elements differs when the pressure-sensitive element expands in a first direction in which one side of the pressure-sensitive element extends and when the pressure-sensitive element compresses in the first direction; the first surface has a plurality of operation areas; and the second surface has a plurality of detection areas located at positions overlapping the plurality of operation areas in a planar view; each of the plurality of pressure-sensitive elements is adhered to each of the plurality of detection areas by a respective one of the plurality of adhesive members so as to be located at the center of each of the plurality of detection areas; and the plurality of pressure-sensitive elements are arranged so that the first direction of each of the plurality of pressure-sensitive elements and the direction in which the plurality of operation areas are arranged are approximately parallel.

[0007] According to the present invention, it is possible to more accurately detect the position of an operation input by pressing.

[0008] FIG. 1 is an exploded perspective view of the touch input device 1. FIG. 2 is an exploded perspective view of the pressure-sensitive element 31. FIG. 3 is a cross-sectional view of the touch input device 1. FIG. 4 is an exploded perspective view of the touch input device 1, showing the expansion and contraction states of each pressure-sensitive element when pressure is applied to the pressure-sensitive element 34. FIG. 5 is an exploded perspective view of the touch input device 1, showing the expansion and contraction states of each pressure-sensitive element when pressure is applied to the pressure-sensitive element 37. FIG. 6 is a diagram showing an example of the output of the pressure-sensitive element when the pressure position is changed. FIG. 7 shows the conditions for the second simulation. FIG. 8 is a diagram showing an example of the output of each pressure-sensitive element when the pressure position is changed in the second simulation. FIG. 9 is a plan view of the pressure-sensitive element 31a and the lead wire L. FIG. 10 is an exploded perspective view of the touch input device 1b. FIG. 11 is an exploded perspective view of the touch input device 1c. FIG. 12 is a block diagram of the touch input device 1c. FIG. 13 is a circuit diagram showing an example of the detection circuit 511. FIG. 14 is a circuit diagram showing an example of the detection circuit 511.

[0009] [First Embodiment] A touch input device 1 according to a first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is an exploded perspective view of the touch input device 1. Fig. 2 is an exploded perspective view of a pressure-sensitive element 31. Fig. 3 is a cross-sectional view of the touch input device 1.

[0010] In the touch-type input device 1, directions are defined as follows, for example. As shown in FIG. 1 , the direction in which the long side of the first surface S1 extends is defined as the left-right direction. The direction in which the short side of the first surface S1 extends is defined as the front-rear direction. The direction in which the first surface S1 and the second surface S2 are aligned is defined as the up-down direction. Viewing in an upward or downward direction corresponds to a planar view according to the present invention. The left-right direction, front-rear direction, and up-down direction are perpendicular to each other. However, the left-right direction, front-rear direction, and up-down direction in this specification are defined for the convenience of explanation and may not coincide with the left-right direction, front-rear direction, and up-down direction when the touch-type input device 1 is in use. Furthermore, in each drawing, the left direction and the right direction may be interchanged, the front direction and the rear direction may be interchanged, and the up-down direction may be interchanged.

[0011] The touch input device 1 comprises a housing 2, a pressure-sensitive element group 3, and adhesive members 41 to 47.

[0012] The housing 2 is made of, for example, an insulating resin. The housing 2 includes a front wall 201, a first side wall 202, and a second side wall 203. The front wall 201, the first side wall 202, and the second side wall 203 are flat plates extending in the left-right direction. The first side wall 202 is connected to the front side of the front wall 201. The second side wall 203 is connected to the rear side of the front wall 201. The first side wall 202 and the second side wall 203 are each perpendicular to the front wall 201. The first side wall 202 is parallel to the second side wall 203. As a result, a space surrounded by the front wall 201, the first side wall 202, and the second side wall 203 is formed below the front wall 201.

[0013] The front wall 201 has a first surface S1 and a second surface S2 that face each other. The first surface S1 and the second surface S2 are aligned in the vertical direction. The first surface S1 and the second surface S2 extend in the left-right direction. The left-right direction corresponds to the longitudinal direction of the first surface according to the present invention.

[0014] The first surface S1 has operation areas 211 to 217 lined up in the left-right direction. A predetermined interval is provided between the operation areas 211 to 217. The operation areas 211 to 217 may be anything that can be recognized by the user, such as marks provided on the first surface S1. The second surface S2 has detection areas 221 to 227. The detection areas 221 to 227 are located at positions that overlap the operation areas 211 to 217 when viewed in the up-down direction. Therefore, the detection areas 221 to 227 are lined up in the left-right direction. It is not necessary to provide a predetermined interval between the operation areas 211 to 217. The operation areas 211 to 217 may also be displayed, for example, on a display or the like.

[0015] The pressure-sensitive element group 3 includes pressure-sensitive elements 31 to 37. When viewed in the vertical direction, the pressure-sensitive elements 31 to 37 are each rectangular with long sides extending in the left-right direction and short sides extending in the front-rear direction. The left-right direction, which is the direction in which the long sides extend (the longitudinal direction of each of the pressure-sensitive elements 31 to 37), corresponds to the first direction according to the present invention. When viewed in the vertical direction, the pressure-sensitive elements 31 to 37 may each be square-shaped. In this embodiment, the pressure-sensitive elements 32 to 37 have the same structure as the pressure-sensitive element 31, and therefore a description thereof will be omitted.

[0016] The pressure-sensitive element 31 is flexible and has a flat membrane shape. As shown in FIG. 2 , the pressure-sensitive element 31 includes a piezoelectric film 311, a reference electrode 312, and a signal electrode 313.

[0017] The piezoelectric film 311 is flat and has upper and lower principal surfaces aligned in the vertical direction. Each of the upper and lower principal surfaces is rectangular with long sides extending in the left-right direction and short sides extending in the front-rear direction.

[0018] The piezoelectric film 311 is polarized by deformation, generating charges on its upper and lower principal surfaces. The charges generated on the upper and lower principal surfaces correspond to the amount of deformation of the piezoelectric film 311. In this embodiment, the charges generated on the upper and lower principal surfaces of the piezoelectric film 311 correspond to the output of the pressure-sensitive element according to the present invention.

[0019] The piezoelectric film 311 is, for example, a film formed from a chiral polymer. The chiral polymer is, for example, polylactic acid (PLA), such as poly-L-lactic acid (PLLA) and poly-D-lactic acid (PDLA). That is, the piezoelectric film 311 contains PLA. The main chain of PLA has a helical structure. PLA has piezoelectricity due to the orientation of its molecules after being uniaxially stretched. The piezoelectric film 311 has a piezoelectric constant of d14.

[0020] The PLA is stretched in at least one axial direction (OD). When viewed from below, the axial direction (OD) of the PLA forms a 45-degree counterclockwise angle with respect to the right. Note that the 45-degree angle may be within a range of approximately 45 degrees ±10 degrees. When the piezoelectric film 311 is stretched or compressed in the left-right direction, electric charges are generated on the upper and lower principal surfaces. The polarity of the electric charges generated when stretched in the left-right direction is different from the polarity of the electric charges generated when compressed in the left-right direction. For example, the polarity of the electric charges generated when stretched in the left-right direction is positive. In this case, the polarity of the electric charges generated when compressed in the left-right direction is negative. Furthermore, the polarity of the electric charges generated when stretched in the front-rear direction is different from the polarity of the electric charges generated when compressed in the front-rear direction. For example, the polarity of the electric charges generated when stretched in the front-rear direction is positive. In this case, the polarity of the electric charges generated when compressed in the front-rear direction is negative. Note that, for example, the axial direction (OD) of the PLA may form a 45-degree clockwise angle with respect to the left, when viewed from below. Furthermore, the polarity of the charge generated when the film is expanded in the left-right direction may be negative, and the polarity of the charge generated when the film is compressed in the left-right direction may be positive.

[0021] The reference electrode 312 is provided on the upper principal surface of the piezoelectric film 311. The reference electrode 312 is made of, for example, copper. The reference electrode 312 is electrically connected to the ground potential, thereby functioning as a reference electrode and a shield conductor. The reference electrode 312 covers the upper principal surface of the piezoelectric film 311. Note that the reference electrode 312 does not necessarily have to cover the upper principal surface of the piezoelectric film 311.

[0022] The signal electrode 313 is provided on the lower main surface of the piezoelectric film 311. The signal electrode 313 is made of, for example, copper. The signal electrode 313 outputs a signal corresponding to the charge generated by the piezoelectric film 311. The signal electrode 313 covers the lower main surface of the piezoelectric film 311. Note that the signal electrode 313 does not have to cover the lower main surface of the piezoelectric film 311.

[0023] 3, each of the adhesive members 41 to 47 is a flat film having substantially the same shape as the pressure-sensitive elements 31 to 37. Each of the pressure-sensitive elements 31 to 37 is adhered to the second surface S2 of the housing 2 by each of the adhesive members 41 to 47. As a result, the pressure-sensitive elements 31 to 37 are housed in a space surrounded by the front wall 201, the first side wall 202, and the second side wall 203.

[0024] As shown in FIG. 1 , each of the pressure-sensitive elements 31-37 is adhered to the corresponding detection area 221-227 by a corresponding adhesive member 41-47 so as to be positioned at the center of the corresponding detection area 221-227. Furthermore, the longitudinal direction of each of the pressure-sensitive elements 31-37 coincides with the longitudinal direction of the first surface S1 in the left-right direction. That is, the pressure-sensitive elements 31-37 are arranged so that their longitudinal directions are parallel to the longitudinal direction of the first surface S1. The longitudinal directions of each of the pressure-sensitive elements 31-37 do not necessarily have to be parallel to the longitudinal direction of the first surface S1, as long as they are approximately parallel to the longitudinal direction of the first surface S1. More specifically, when viewed from the top-bottom direction, the longitudinal directions of each of the pressure-sensitive elements 31-37 may be tilted within a range of ±10 degrees with respect to the longitudinal direction of the first surface S1.

[0025] Hereinafter, the detection of an operation input by pressing and an operation input position by the touch-type input device 1 will be described with reference to the drawings. Fig. 4 is an exploded perspective view of the touch-type input device 1, showing the expansion and contraction states of each pressure-sensitive element when the pressure-sensitive element 34 is pressed. Fig. 5 is an exploded perspective view of the touch-type input device 1, showing the expansion and contraction states of each pressure-sensitive element when the pressure-sensitive element 37 is pressed.

[0026] As shown in Figure 4, for example, when the center of the operation area 214 of the housing 2 is pressed, the front wall 201 distorts downward, and the pressure-sensitive elements 31 to 37 expand or compress. At this time, the pressure-sensitive element 34 expands in the left-right and front-back directions. Therefore, the polarity of the charge generated by the pressure-sensitive element 34 is positive. The pressure-sensitive elements 31 to 33 and 35 to 37 each compress in the left-right direction. Therefore, the polarity of the charge generated by the pressure-sensitive elements 31 to 33 and 35 to 37 is negative.

[0027] The compression amounts of the pressure-sensitive elements 31 to 33 and 35 to 37 increase the closer they are to the pressure-sensitive element 34. Therefore, of the left-right compression amounts of the pressure-sensitive elements 31 to 33, the left-right compression amount of the pressure-sensitive element 33 is the largest, and the left-right compression amount of the pressure-sensitive element 31 is the smallest. Similarly, of the left-right compression amounts of the pressure-sensitive elements 35 to 37, the left-right compression amount of the pressure-sensitive element 35 is the largest, and the left-right compression amount of the pressure-sensitive element 37 is the smallest.

[0028] As shown in Figure 5, for example, when the center of the operation area 217 of the housing 2 is pressed, the front wall 201 distorts downward, and the pressure-sensitive elements 31 to 37 each expand or compress. At this time, the pressure-sensitive element 37 expands in the left-right and front-back directions. Therefore, the polarity of the charge generated by the pressure-sensitive element 37 is positive. The pressure-sensitive elements 31 to 36 each compress in the left-right direction. Therefore, the polarity of the charge generated by each of the pressure-sensitive elements 31 to 36 is negative.

[0029] The compression amount of the pressure-sensitive elements 31 to 36 increases as they approach the pressure-sensitive element 37. Therefore, of the compression amounts of the pressure-sensitive elements 31 to 36 in the left-right direction, the compression amount of the pressure-sensitive element 36 is the largest, and the compression amount of the pressure-sensitive element 31 is the smallest.

[0030] As described above, the operation input by pressing and the operation input position can be detected from the polarity of the charge generated by the pressure sensitive elements 31 to 37.

[0031] The touch-type input device 1 can detect an input position by pressing more accurately. In the touch-type input device described in Patent Document 1 (Japanese Patent No. 6156587), multiple piezoelectric elements are attached to the rear surface of the housing with a single adhesive member. Therefore, when any position on the surface of the housing is pressed, the deformation of the housing is transmitted to the multiple piezoelectric elements via the adhesive member. Therefore, even if an area where no piezoelectric element is located is pressed, an electric charge is generated due to the expansion and contraction of the piezoelectric element, which may prevent accurate detection of the input position.

[0032] On the other hand, in the touch-type input device 1, each of the pressure-sensitive elements 31-37 is adhered to a corresponding one of the detection areas 221-227 by a corresponding one of the adhesive members 41-47. In other words, multiple pressure-sensitive elements are not adhered to the second surface S2 of the housing 2 by a single adhesive member. This prevents deformation of the housing 2 from being transmitted to multiple pressure-sensitive elements via a single adhesive member, regardless of the pressure-applied position on the housing 2. Furthermore, the polarity of the output of each of the pressure-sensitive elements 31-37 differs depending on whether the pressure-sensitive element 31-37 expands or contracts in its longitudinal direction. Therefore, the polarity of the output of a pressure-sensitive element differs when an operation area on a certain pressure-sensitive element is pressed compared to when an operation area other than that pressure-sensitive element is pressed. As a result, the touch-type input device 1 can more accurately detect the operation input position due to pressure based on the polarity of the output of the pressure-sensitive elements 31-37.

[0033] The present inventors conducted two simulations to confirm the effect of the distance between the centers of the pressure-sensitive elements on the output of each pressure-sensitive element. The two simulations conducted by the present inventors (hereinafter referred to as the first simulation and the second simulation, respectively) are described below with reference to the drawings. FIG. 6 is a diagram showing an example of the output of the pressure-sensitive element when the pressing position is changed. The horizontal axis in FIG. 6 represents the pressing position [mm]. The vertical axis in FIG. 6 represents the output of the pressure-sensitive element. FIG. 7 shows the conditions for the second simulation. FIG. 8 is a diagram showing an example of the output of each pressure-sensitive element when the pressing position is changed in the second simulation.

[0034] In the first and second simulations, the length of the long side of each of the pressure-sensitive elements 31 to 37 was 14 mm, and the length of the short side was 3 mm. In Figure 6, a pressure position of 0 mm indicates that the center of a pressure-sensitive element is pressed. A positive pressure position indicates that the right part of the pressure-sensitive element is pressed, and the pressure position [mm] indicates the distance between the pressure position and the center of the pressure-sensitive element. A negative pressure position indicates that the left part of the pressure-sensitive element is pressed, and the pressure position [mm] indicates the distance between the pressure position and the center of the pressure-sensitive element.

[0035] As shown in Figure 6, when the pressed position was in the range of greater than -8 mm and less than 9 mm, the polarity of the output of the pressure-sensitive element was positive. When the pressed position was -8 mm or less and when the pressed position was 9 mm or more, the polarity of the output of the pressure-sensitive element was negative. Therefore, if the distance between the centers of adjacent pressure-sensitive elements is 9 mm or more, when a certain operation area is pressed, the operation area can be set so that the polarity of the output of the pressure-sensitive element located under that operation area is different from the polarity of the output of the pressure-sensitive element located under operation areas other than that operation area.

[0036] As shown in FIG. 7, in the second simulation, the distance between the centers of adjacent pressure-sensitive elements is 15 mm, which is greater than or equal to 9 mm.

[0037] As shown in Figure 8, when an operation area on a certain pressure-sensitive element is pressed, the polarity of the output of that pressure-sensitive element is positive. When an operation area other than on a certain pressure-sensitive element is pressed, the polarity of the output of that pressure-sensitive element is negative. When the area to the left of operation area 211 or the area to the right of operation area 217 is pressed, the polarities of the outputs of pressure-sensitive elements 31 to 37 are all negative.

[0038] When the midpoint between operation area 214 and operation area 215 is pressed, the polarity of the output of pressure-sensitive elements 31 to 33, 36, and 37 is negative. On the other hand, since the distance between the midpoint between operation area 214 and operation area 215 and pressure-sensitive element 34 or pressure-sensitive element 35 is 7.5 mm, which is less than 9 mm, when the midpoint between operation area 214 and operation area 215 is pressed, the polarity of the output of pressure-sensitive elements 34 and 35 is positive. The polarity of the output of pressure-sensitive elements 34 and 35 is different from the polarity of the output of pressure-sensitive elements 31 to 33, 36, and 37.

[0039] The pressure-sensitive elements 31 to 37 may be arranged so that the direction in which the short sides of each of the pressure-sensitive elements 31 to 37 extend (short-side direction) is approximately parallel to the longitudinal direction of the first surface S1. However, by arranging the pressure-sensitive elements 31 to 37 so that the longitudinal direction of each of the pressure-sensitive elements 31 to 37 is approximately parallel to the longitudinal direction of the first surface S1, the sensitivity of each of the pressure-sensitive elements 31 to 37 can be improved. Furthermore, if the pressure-sensitive elements 31 to 37 are each square-shaped when viewed from the top to bottom, the pressure-sensitive elements 31 to 37 may be arranged so that the direction in which one side of each of the pressure-sensitive elements 31 to 37 extends is approximately parallel to the longitudinal direction of the first surface S1.

[0040] The pressure-sensitive elements 31 to 37 may be arranged so that the operation areas 211 to 217 are aligned in the front-to-rear direction and the long sides of the pressure-sensitive elements 31 to 37 are substantially parallel to the front-to-rear direction.

[0041] [First Modification] A pressure-sensitive element 31a according to a first modification of the present invention will be described below with reference to the drawings. Fig. 9 is a plan view of the pressure-sensitive element 31a and the lead wires L. Regarding the pressure-sensitive element 31a, only the differences from the pressure-sensitive element 31 will be described, and the rest will be omitted.

[0042] The pressure-sensitive element 31a differs from the pressure-sensitive element 31 in that it includes a strain gauge. The touch-type input device 1 according to the first modification is provided with the pressure-sensitive element 31a instead of the pressure-sensitive element 31. Note that the touch-type input device 1 may also be provided with the pressure-sensitive element 31a instead of each of the pressure-sensitive elements 32 to 37.

[0043] As shown in FIG. 9 , the pressure-sensitive element 31a has a strain sensing portion 314. The strain sensing portion 314 is a metal foil. The change in electrical resistance of the strain sensing portion 314 is dominant in the change in electrical resistance of the pressure-sensitive element 31a. The strain sensing portion 314 extends in the left-right direction. That is, the longitudinal direction of the strain sensing portion 314 and the longitudinal direction of the first surface S1 coincide in the left-right direction. The longitudinal direction of the strain sensing portion 314 does not necessarily have to be parallel to the longitudinal direction of the first surface S1, as long as it is approximately parallel to the longitudinal direction of the first surface S1. More specifically, when viewed in the up-down direction, the longitudinal direction of the strain sensing portion 314 may be tilted within a range of ±10 degrees with respect to the longitudinal direction of the first surface S1. Lead wires L are connected to both ends of the strain sensing portion 314 via gauge tabs.

[0044] The electrical resistance of the pressure-sensitive element 31a changes when it is stretched or compressed in the left-right direction. The polarity of the change in electrical resistance when it is stretched in the left-right direction is different from the polarity of the change in electrical resistance when it is compressed in the left-right direction. More specifically, when the pressure-sensitive element 31a stretches in the left-right direction, the strain-sensing portion 314 stretches in the left-right direction. As a result, the cross-sectional area of ​​the strain-sensing portion 314 decreases, and the electrical resistance of the strain-sensing portion 314 increases. Therefore, the electrical resistance of the pressure-sensitive element 31a increases. The polarity of the change in electrical resistance when the pressure-sensitive element 31a stretches in the left-right direction is positive. On the other hand, when the pressure-sensitive element 31a compresses in the left-right direction, the strain-sensing portion 314 compresses in the left-right direction. As a result, the cross-sectional area of ​​the strain-sensing portion 314 increases, and the electrical resistance of the strain-sensing portion 314 decreases. Therefore, the electrical resistance of the pressure-sensitive element 31a decreases. When the pressure-sensitive element 31a is compressed in the left-right direction, the polarity of the change in electrical resistance is negative. In this modification, the change in electrical resistance of the pressure-sensitive element 31a corresponds to the output of the pressure-sensitive element according to the present invention.

[0045] The touch input device 1 including the pressure sensitive element 31 a also achieves the same effects as the touch input device 1 including the pressure sensitive element 31 .

[0046] The pressure-sensitive element 31a may include a piezoresistance element. Similar to a strain gauge, a piezoresistance element changes its electrical resistance when deformed. When the pressure-sensitive element 31a includes a piezoresistance element, it is sufficient that the portion of the pressure-sensitive element 31a where the change in electrical resistance is dominant extends in the left-right direction.

[0047] [Second Modification] A touch input device 1b according to a second modification of the present invention will be described below with reference to the drawings. Fig. 10 is an exploded perspective view of the touch input device 1b. Note that, with regard to the touch input device 1b, only the parts that are different from the touch input device 1 will be described, and the rest will be omitted.

[0048] The touch-type input device 1b differs from the touch-type input device 1 in that the pressure-sensitive element group 3 includes a piezoelectric film 301, reference electrodes 312, 322, 332, 342, 352, 362, and 372, and signal electrodes 313, 323, 333, 343, 353, 363, and 373. Note that the piezoelectric film 301 has the same structure as the piezoelectric film 311, and therefore a description thereof will be omitted.

[0049] 10, when viewed in the vertical direction, the piezoelectric film 301 overlaps all of the operation areas 211 to 217. When viewed in the vertical direction, the outer edge of the piezoelectric film 301 surrounds the outer edges of the operation areas 211 to 217.

[0050] Reference electrodes 312, 322, 332, 342, 352, 362, and 372 are provided on the upper main surface of piezoelectric film 301. Signal electrodes 313, 323, 333, 343, 353, 363, and 373 are provided on the lower main surface of piezoelectric film 301. The portion of piezoelectric film 301 where reference electrode 312 and signal electrode 313 are arranged opposite each other is pressure-sensitive element 310. Similarly, the portion of piezoelectric film 301 where reference electrode 322 and signal electrode 323 are arranged opposite each other is pressure-sensitive element 320. The portion of piezoelectric film 301 where reference electrode 332 and signal electrode 333 are arranged opposite each other is pressure-sensitive element 330. The portion of piezoelectric film 301 where reference electrode 342 and signal electrode 343 are arranged opposite each other is pressure-sensitive element 340. The portion where reference electrode 352 and signal electrode 353 are arranged opposite each other on both main surfaces of piezoelectric film 301 is pressure-sensitive element 350. The portion where reference electrode 362 and signal electrode 363 are arranged opposite each other on both main surfaces of piezoelectric film 301 is pressure-sensitive element 360. The portion where reference electrode 372 and signal electrode 373 are arranged opposite each other on both main surfaces of piezoelectric film 301 is pressure-sensitive element 370. That is, in this modification as well, pressure-sensitive element group 3 includes pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370.

[0051] When viewed in the vertical direction, the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 are each rectangular with long sides extending in the left-right direction and short sides extending in the front-to-back direction. Therefore, in this modified example, the left-to-right direction, which is the direction in which the long sides extend (the longitudinal direction of each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370), corresponds to the first direction according to the present invention. When viewed in the vertical direction, the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 may each be square. Each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 is adhered to each of the detection areas 221 to 227 by adhesive members 41 to 47, respectively, so as to be positioned at the center of each of the detection areas 221 to 227.

[0052] Furthermore, the longitudinal direction of each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 coincides with the longitudinal direction of the first surface S1 in the left-right direction. That is, the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 are arranged so that the longitudinal direction of each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 is parallel to the longitudinal direction of the first surface S1. Note that the longitudinal direction of each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 does not necessarily have to be parallel to the longitudinal direction of the first surface S1, as long as it is approximately parallel to the longitudinal direction of the first surface S1. More specifically, when viewed in the vertical direction, the longitudinal direction of each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 may be tilted within a range of ±10 degrees with respect to the longitudinal direction of the first surface S1.

[0053] The touch input device 1b also has the same effects as the touch input device 1.

[0054] The pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 may be arranged so that the direction in which the short sides of each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 extend (short-side direction) is approximately parallel to the longitudinal direction of the first surface S1. However, by arranging the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 so that the longitudinal direction of each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 is approximately parallel to the longitudinal direction of the first surface S1, the sensitivity of each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 can be improved. Furthermore, when viewed from the top to bottom, if the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 are each square-shaped, the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 may be arranged so that the direction in which one side of each of the pressure-sensitive elements 310, 320, 330, 340, 350, 360, and 370 extends is approximately parallel to the longitudinal direction of the first surface S1.

[0055] [Third Modification] A touch input device 1c according to a third modification of the present invention will be described below with reference to the drawings. Fig. 11 is an exploded perspective view of the touch input device 1c. Fig. 12 is a block diagram of the touch input device 1c. Fig. 13 is a circuit diagram showing an example of a detection circuit 511. Fig. 14 is a circuit diagram showing an example of a detection circuit 511. Note that with regard to the touch input device 1c, only the parts that are different from the touch input device 1 will be described, and the rest will be omitted.

[0056] The touch input device 1c differs from the touch input device 1 in that it further includes a circuit board 5. As shown in Fig. 11 , the circuit board 5, like the pressure-sensitive elements 31 to 37, is housed in a space surrounded by a front wall 201, a first side wall 202, and a second side wall 203. Note that the circuit board 5 does not have to be housed in a space surrounded by the front wall 201, the first side wall 202, and the second side wall 203.

[0057] 12, the circuit board 5 includes detection circuits 511-517 and an MPU 52. The detection circuits 511-517 are electrically connected to the pressure-sensitive elements 31-37, respectively. More specifically, the detection circuits 511-517 are electrically connected to the reference electrodes and signal electrodes of the pressure-sensitive elements 31-37, respectively. The circuit board 5 may further include an amplifier circuit provided between each of the detection circuits 511-517 and the MPU 52.

[0058] For example, if the pressure-sensitive element 31 includes a piezoelectric film 311, a reference electrode 312, and a signal electrode 313, the detection circuit 511 may be a charge amplifier as shown in Fig. 13. An input terminal IT of the charge amplifier is connected to the signal electrode 313 of the pressure-sensitive element 31. An output terminal OT of the charge amplifier is connected to the MPU 52. Similarly, if each of the pressure-sensitive elements 32 to 37 includes a piezoelectric film, a reference electrode, and a signal electrode, each of the detection circuits 512 to 517 may be a charge amplifier.

[0059] For example, if the pressure-sensing element 31 includes a strain gauge or a piezo-resistance element, the detection circuit 511 may be a Wheatstone bridge as shown in Fig. 14. An input terminal IT of the Wheatstone bridge is connected to lead wires L connected to both ends of the strain sensing portion 314. An output terminal OT of the Wheatstone bridge is connected to the MPU 52. Similarly, if each of the pressure-sensing elements 32 to 37 includes a strain gauge or a piezo-resistance element, each of the detection circuits 512 to 517 may be a Wheatstone bridge.

[0060] 12, the MPU 52 has a control circuit 521 and a memory 522. The output signals of the detection circuits 511 to 517 are input to the control circuit 521. The memory 522 has, for example, a ROM (Read Only Memory) and a RAM (Random Access Memory). The control circuit 521 reads out a program stored in the ROM into the RAM.

[0061] The control circuit 521 has a polarity determination unit 5211 and an operation area determination unit 5212. The polarity determination unit 5211 and the operation area determination unit 5212 are realized as software of the MPU 52. The polarity determination unit 5211 determines the polarity of each output from the pressure-sensitive elements 31 to 37 based on the output from each of the pressure-sensitive elements 31 to 37. The polarity determination unit 5211 may be realized as hardware using a comparator or the like.

[0062] The operation area determination unit 5212 determines the operation input position by pressing based on the determination result of the polarity of the output of each of the pressure-sensitive elements 31 to 37 by the polarity determination unit 5211. For example, the operation area determination unit 5212 determines that the operation input position is the operation area corresponding to the pressure-sensitive element whose output polarity is positive.

[0063] The touch input device 1c also has the same effects as the touch input device 1.

[0064] The operation area determination unit 5212 may determine whether an input operation has been performed on a pressure-sensitive element whose output polarity is positive. A method for determining whether an input operation has been performed is, for example, the method described in Japanese Patent No. 7279864. For example, the operation area determination unit 5212 may determine, as the operation input position, an operation area corresponding to a pressure-sensitive element whose output polarity has been positive for a certain period of time or more.

[0065] As described above, the polarity of the charge generated when the piezoelectric film expands in the left-right direction may be negative, and the polarity of the charge generated when the piezoelectric film compresses in the left-right direction may be positive. In this case, the operation area determination unit 5212 determines that the operation area corresponding to the pressure-sensitive element whose output polarity is negative is the operation input position.

[0066] Furthermore, the operation area determination unit 5212 may determine that an operation area corresponding to one pressure-sensitive element is an operation input position when the polarity of the output of the pressure-sensitive element is different from the polarity of the output of pressure-sensitive elements other than the pressure-sensitive element. In this case, the number of pressure-sensitive elements is three or more. Note that, as described above, if the distance between adjacent operation areas is short, when an area between adjacent operation areas is pressed, the polarities of the outputs of the pressure-sensitive elements corresponding to the adjacent operation areas may become the same. Therefore, when this determination method is adopted, it is desirable that the number of pressure-sensitive elements is four or more. By using four or more pressure-sensitive elements, it is possible to prevent the operation area determination unit 5212 from determining that an operation area other than the adjacent operation area has been pressed when an area between adjacent operation areas is pressed.

[0067] When the distance between adjacent operation areas is short and the area between the adjacent operation areas is pressed, as described above, the polarity of the output of the two adjacent pressure-sensitive elements corresponding to the adjacent operation areas is different from the polarity of the output of the pressure-sensitive elements other than the two adjacent operation areas. In this case, the operation area determination unit 5212 may determine that the area between the adjacent operation areas is the operation input position. This makes it possible to set a maximum of (the number of pressure-sensitive elements × 2 - 1) operation areas. Alternatively, operations on the area between the adjacent operation areas can be ignored.

[0068] Other Embodiments The touch input device according to the present invention is not limited to the touch input devices 1, 1b, and 1c, and may be modified within the scope of the present invention. In addition, the structures of the touch input devices 1, 1b, and 1c may be combined arbitrarily.

[0069] The present invention has the following configuration.

[0070] (1) A touch-type input device comprising: a housing having opposing first and second surfaces; a plurality of pressure-sensitive elements each having a rectangular shape in a planar view; and a plurality of adhesive members; wherein the polarity of the output of each of the plurality of pressure-sensitive elements differs between when the pressure-sensitive element expands in a first direction in which one side of the pressure-sensitive element extends and when the pressure-sensitive element compresses in the first direction; the first surface has a plurality of operation areas, which are aligned in the longitudinal direction of the first surface; the second surface has a plurality of detection areas located at positions overlapping the plurality of operation areas in a planar view; each of the plurality of pressure-sensitive elements is adhered to each of the plurality of detection areas by a respective one of the plurality of adhesive members so as to be located at the center of each of the plurality of detection areas; and the plurality of pressure-sensitive elements are arranged so that the first direction of each of the plurality of pressure-sensitive elements is approximately parallel to the longitudinal direction of the first surface.

[0071] (2) The touch input device according to (1), wherein the distance between the centers of the adjacent pressure-sensitive elements is 9 mm or more.

[0072] (3) The touch-type input device according to (1) or (2), further comprising: a polarity determination unit that determines the polarity of the output of each of the plurality of pressure-sensitive elements based on the output of each of the plurality of pressure-sensitive elements; and an operation area determination unit that determines an operation input position based on the determination result of the polarity of the output of each of the plurality of pressure-sensitive elements by the polarity determination unit.

[0073] (4) The touch-type input device according to (3), wherein the operation area determination unit determines the operation area corresponding to the pressure-sensitive element whose output polarity is positive as the operation input position.

[0074] (5) The touch input device according to (3) or (4), wherein the number of the pressure-sensitive elements is four or more.

[0075] (6) The touch-type input device according to (5), wherein the operation area determination unit determines the operation area corresponding to one of the pressure-sensitive elements as the operation input position when the polarity of the output of the one of the pressure-sensitive elements is different from the polarity of the output of the pressure-sensitive elements other than the one of the pressure-sensitive elements.

[0076] (7) The touch-type input device according to (5) or (6), wherein the operation area determination unit determines, when the polarity of the output of two adjacent pressure-sensitive elements is different from the polarity of the output of a pressure-sensitive element other than the two adjacent pressure-sensitive elements, that an area between the operation areas corresponding to the two adjacent pressure-sensitive elements is the operation input position.

[0077] (8) The touch input device according to any one of (1) to (7), wherein the pressure-sensitive elements include piezoelectric films.

[0078] (9) The touch input device according to (8), wherein the piezoelectric film has polylactic acid stretched in at least one axial direction.

[0079] (10) The touch input device according to any one of (1) to (9), wherein the plurality of pressure-sensitive elements include strain gauges.

[0080] (11) The touch input device according to any one of (1) to (10), wherein the pressure-sensitive elements include piezo-resistive elements.

[0081] (12) The touch-type input device according to any one of (1) to (11), wherein each of the pressure-sensitive elements has a rectangular shape having long sides and short sides in a plan view, and the first direction is a direction in which the long sides extend.

[0082] 1, 1b, 1c: Touch-type input device 2: Housing 3: Pressure-sensitive element group 5: Circuit board 31, 31a, 32-37, 310, 320, 330, 340, 350, 360, 370: Pressure-sensitive elements 41-47: Adhesive member 52: MPU 201: Front wall 202: First side wall 203: Second side wall 211-217: Operation area 221-227: Detection area 301, 311: Piezoelectric film 312, 322, 332, 342, 352, 362, 372: Reference electrode 313, 323, 333, 343, 353, 363, 373: Signal electrode 314: Strain sensing portion 511-517: Detection circuit 521: Control circuit 522: Memory 5211: Polarity determination section 5212: Operation area determination section IT: Input terminal L: Lead wire OD: Uniaxial direction OT: Output terminal S1: First surface S2: Second surface

Claims

1. A touch-type input device comprising: a housing having opposing first and second surfaces; a plurality of pressure-sensitive elements each rectangular in a planar view; and a plurality of adhesive members; wherein the polarity of the output of each of the plurality of pressure-sensitive elements differs when the pressure-sensitive element is expanded in a first direction in which one side of the pressure-sensitive element extends and when the pressure-sensitive element is compressed in the first direction; the first surface has a plurality of operation areas; and the second surface has a plurality of detection areas located in positions overlapping the plurality of operation areas in a planar view; each of the plurality of pressure-sensitive elements is adhered to each of the plurality of detection areas by a respective one of the plurality of adhesive members so as to be located in the center of each of the plurality of detection areas; and the plurality of pressure-sensitive elements are arranged so that the first direction of each of the plurality of pressure-sensitive elements and the direction in which the plurality of operation areas are arranged are approximately parallel.

2. The touch input device according to claim 1, wherein the direction in which the plurality of operation areas are arranged is the longitudinal direction of the first surface.

3. A touch input device according to claim 1 or claim 2, wherein the distance between the centers of adjacent pressure-sensitive elements is 9 mm or more.

4. A touch-type input device as described in any one of claims 1 to 3, further comprising: a polarity determination unit that determines the polarity of the output of each of the plurality of pressure-sensitive elements based on the output of each of the plurality of pressure-sensitive elements; and an operation area determination unit that determines an operation input position based on the determination result of the polarity of the output of each of the plurality of pressure-sensitive elements by the polarity determination unit.

5. The touch input device according to claim 4, wherein the operation area determination unit determines the operation area corresponding to the pressure-sensitive element whose output polarity is positive as the operation input position.

6. The touch input device according to claim 4 or claim 5, wherein the number of the plurality of pressure-sensitive elements is four or more.

7. The touch-type input device according to claim 6, wherein the operation area determination unit determines the operation area corresponding to one of the pressure-sensitive elements as the operation input position when the polarity of the output of the one of the pressure-sensitive elements is different from the polarity of the output of the pressure-sensitive elements other than the one of the pressure-sensitive elements.

8. A touch-type input device according to claim 6 or claim 7, wherein the operation area determination unit determines the area between the operation areas corresponding to the two adjacent pressure-sensitive elements as the operation input position when the polarity of the output of two adjacent pressure-sensitive elements is different from the polarity of the output of a pressure-sensitive element other than the two adjacent pressure-sensitive elements.

9. The touch input device according to any one of claims 1 to 8, wherein the plurality of pressure-sensitive elements include piezoelectric films.

10. The touch input device according to claim 9, wherein the piezoelectric film comprises polylactic acid stretched in at least one direction.

11. The touch input device according to any one of claims 1 to 10, wherein the plurality of pressure-sensitive elements include strain gauges.

12. The touch input device according to any one of claims 1 to 11, wherein the plurality of pressure-sensitive elements include piezo-resistive elements.

13. A touch-type input device according to any one of claims 1 to 12, wherein each of the plurality of pressure-sensitive elements is rectangular in shape having long and short sides in a plan view, and the first direction is the direction in which the long sides extend.

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