Deformation detection sensor and electronic device

Abstract

A deformation detection sensor according to the present invention comprises: a flexible substrate that has a substrate upper main surface and a curved section; a first sensor that outputs a first detection signal corresponding to deformation of the curved section, that is provided on the substrate upper main surface, and that has a first upper main surface and a first lower main surface; a first deformation inhibition member; and a second deformation inhibition member. The first sensor includes a first piezoelectric film. The first deformation inhibition member has a first region that overlaps the first piezoelectric film when viewed in the vertical direction. The second deformation inhibition member has a second region that overlaps the first piezoelectric film when viewed in the vertical direction. The first region and the second region have respective portions that do not contact each other when viewed in the vertical direction, in a state in which the flexible substrate is not bent.

Description

Deformation detection sensor and electronic device

[0001] The present invention relates to a deformation detection sensor and an electronic device equipped with the deformation detection sensor.

[0002] A known example of a conventional invention relating to a deformation detection sensor is the bending sensor described in Patent Document 1. This bending sensor includes a piezoelectric element disposed on a bendable substrate, a voltage detection circuit that detects the voltage generated in the piezoelectric element, and a calculation unit that integrates the voltage detected by the voltage detection circuit to calculate an integral value and associates the integral value with the bending angle of the substrate.

[0003] International Publication No. 2021 / 256252

[0004] Incidentally, there is a demand for the bending sensor described in Patent Document 1 to detect the bending angle of the substrate with high accuracy.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a deformation detection sensor and an electronic device that can accurately detect the bending angle of a substrate.

[0006] a first sensor that outputs a first detection signal corresponding to deformation of the curved section and that is provided on the upper main surface of the substrate and has a first upper main surface and a first lower main surface that are aligned in the vertical direction; a first deformation inhibiting member; and a second deformation inhibiting member, wherein the first sensor includes: a first piezoelectric film that has a first piezoelectric film upper main surface and a first piezoelectric film lower main surface that are aligned in the vertical direction; a first upper electrode that is provided on the upper main surface of the first piezoelectric film; and a first lower electrode that is provided on the lower main surface of the first piezoelectric film; and the first deformation inhibiting member is provided on the first upper main surface or the first lower main surface, and the first deformation inhibiting member has a first region that overlaps with the first piezoelectric film when viewed in the vertical direction. The second deformation inhibiting member is provided on the first upper main surface or the first lower main surface on which the first deformation inhibiting member is provided, and the second deformation inhibiting member has a second region that overlaps with the first piezoelectric film when viewed in the vertical direction, and the first region and the second region have portions that do not contact each other when viewed in the vertical direction when the flexible substrate is not bent.

[0007] In this specification, directions are defined as follows. In the deformation detection sensor 1, the direction in which the substrate upper principal surface US2 and the substrate lower principal surface LS2 of the flexible substrate 2 are aligned is defined as the up-down direction. Furthermore, the direction in which the long sides of the substrate upper principal surface US2 extend when viewed in the up-down direction is defined as the left-right direction. When viewed in the up-down direction, the direction in which the short sides of the substrate upper principal surface US2 extend is defined as the front-rear direction. The up-down direction, left-right direction, and front-rear direction are mutually perpendicular. Furthermore, in the deformation detection sensor 1, the direction in which the first piezoelectric film upper principal surface US31 and the first piezoelectric film lower principal surface LS31 of the first piezoelectric film 31 are aligned when the first piezoelectric film 31 is unfolded on a plane is defined as the piezoelectric film up-down direction. Furthermore, the direction in which the long sides of the first piezoelectric film 31 extend when viewed in the piezoelectric film up-down direction is defined as the piezoelectric film left-right direction. When viewed in the piezoelectric film up-down direction, the direction in which the short sides of the first piezoelectric film 31 extend is defined as the piezoelectric film front-rear direction. The up-down direction, left-right direction, and front-to-back direction of the piezoelectric film are perpendicular to one another. Note that the definitions of directions in this specification are merely examples. Therefore, the directions in the actual use of the deformation detection sensor 1 do not necessarily have to match the directions in this specification. Furthermore, the up-down direction may be reversed in FIGS. 1 to 13, 18, 21 to 25, and 27 to 34. The left-to-right direction may be reversed in FIGS. 1 to 13, 18, 21 to 25, and 27 to 34. The front-to-back direction may be reversed in FIGS. 1 to 13, 18, 21 to 25, and 27 to 34. Furthermore, the up-down direction of the piezoelectric film may be reversed in FIGS. 1 to 3, 5 to 10, 12, 21 to 25, and 27 to 34. The left-to-right direction of the piezoelectric film may be reversed in FIGS. 1 to 3, 5 to 10, 12, 21 to 25, and 27 to 34. 1 to 3, 5 to 10, 12, 21 to 25, and 27 to 34, the front-to-rear direction of the piezoelectric film may be reversed.

[0008] In the following, X and Y are parts or members of the deformation detection sensor 1. In this specification, unless otherwise specified, each part of X is defined as follows: The upper part of X means the upper half of X. The upper end of X means the upper end of X. The upper end part of X means the upper end of X and its vicinity. This definition also applies to directions other than the upward direction.

[0009] Furthermore, "X is located above Y" means that X is located directly above Y. Therefore, when viewed in the vertical direction, X overlaps with Y. "X is located above Y" means that X is located directly above Y and that X is located diagonally above Y. Therefore, when viewed in the vertical direction, X may or may not overlap with Y. This definition also applies to directions other than the upward direction.

[0010] In this specification, "X and Y are electrically connected" means that electricity is conducted between X and Y. Therefore, X and Y may or may not be in contact with each other. When X and Y are not in contact with each other, a conductive element Z is disposed between X and Y.

[0011] In this specification, the bending angle θ of the flexible substrate 2 is defined as follows: The bending angle θ of the flexible substrate 2 is defined as the angle formed between the first portion P1 of the flexible substrate 2 and the second portion P2 of the flexible substrate 2 when viewed in the direction in which the first bending line L1 extends.

[0012] The deformation detection sensor according to the present invention can detect the bending angle of the substrate with high accuracy.

[0013] FIG. 1 is an exploded perspective view of a deformation detection sensor 1 according to the first embodiment. FIG. 2 is a perspective view of the deformation detection sensor 1 according to the first embodiment. FIG. 3 is a cross-sectional view of the deformation detection sensor 1 according to the first embodiment when the bending angle θ of the flexible substrate 2 is 0 degrees, as viewed in the front direction. FIG. 4 is a cross-sectional view of the deformation detection sensor 1 according to the first embodiment when the bending angle θ of the flexible substrate 2 is 180 degrees, as viewed in the front direction. FIG. 5 is a cross-sectional view of the first sensor 3 according to the first embodiment when viewed in the front direction. FIG. 6 is a plan view of the first sensor 3 according to the first embodiment when viewed in the downward direction. FIG. 7 is a plan view of the deformation detection sensor 1 according to the first embodiment when viewed in the downward direction. FIG. 8 is a plan view of the deformation detection sensor 1 according to the first embodiment when viewed in the downward direction. FIG. 9 is an exploded perspective view of the electronic device 100 according to the first embodiment. FIG. 10 is a cross-sectional view of the electronic device 100 according to the first embodiment when the bending angle θ of the flexible substrate 2 is 0 degrees, as viewed in the front direction. FIG. 11 is a cross-sectional view of the electronic device 100 according to the first embodiment, viewed from the front, when the bending angle θ of the flexible substrate 2 is 180 degrees. FIG. 12 is a cross-sectional view of the deformation detection sensor 10 according to the comparative example, viewed from the front, when the bending angle θ of the flexible substrate 2 according to the comparative example is 0 degrees. FIG. 13 is a cross-sectional view of the deformation detection sensor 10 according to the comparative example, viewed from the front, when the bending angle θ of the flexible substrate 2 according to the comparative example is 180 degrees. FIG. 14 is an example of the first detection signal SigD1 when the bending angle θ of the flexible substrate 2 according to the comparative example is changed from 0 degrees to 180 degrees. FIG. 15 is an example of the first integral value IV1 when the bending angle θ of the flexible substrate 2 according to the comparative example is changed from 0 degrees to 180 degrees. FIG. 16 is an example of the first integral value IV1 when noise N is superimposed on the first detection signal SigD1 when the bending angle θ of the flexible substrate 2 according to the comparative example is changed from 0 degrees to 180 degrees. Fig. 17 shows an example of the first detection signal SigD1 when the bending angle θ of the flexible substrate 2 according to the first embodiment is changed from 0 degrees to 180 degrees. Fig. 18 shows a cross-sectional view of the deformation detection sensor 1 and the flexible substrate 2 according to the first embodiment, viewed from the front, when the bending angle θ of the flexible substrate 2 is θa. Fig. 19 shows an example of the first integral value IV1 when the bending angle θ of the flexible substrate 2 according to the first embodiment is changed from 0 degrees to 180 degrees.FIG. 20 shows an example of the first integral value IV1 when noise N is superimposed on the first detection signal SigD1 when the bending angle θ of the flexible substrate 2 according to the first embodiment is changed from 0 degrees to 180 degrees. FIG. 21 is an exploded perspective view of a deformation detection sensor 1a according to a first modified example. FIG. 22 is a plan view of a deformation detection sensor 1b according to a second modified example, viewed from below. FIG. 23 is a plan view of a deformation detection sensor 1c according to a third modified example, viewed from below. FIG. 24 is an exploded perspective view of a deformation detection sensor 1d according to the second embodiment. FIG. 25 is an exploded perspective view of an electronic device 100d according to the second embodiment. FIG. 26 shows an example of the second integral value IV2 when noise N is superimposed on the second detection signal SigD2 when the bending angle θ of the flexible substrate 2 according to the second embodiment is changed from 0 degrees to 180 degrees. FIG. 27 is an exploded perspective view of a deformation detection sensor 1e according to a fourth modified example. FIG. 28 is an exploded perspective view of a deformation detection sensor 1f according to the third embodiment. Fig. 29 is a plan view of a deformation detection sensor 1f according to the third embodiment viewed from below. Fig. 30 is an exploded perspective view of a deformation detection sensor 1g according to a fifth modified example. Fig. 31 is a plan view of a deformation detection sensor 1h according to a sixth modified example viewed from below. Fig. 32 is a plan view of a deformation detection sensor 1i according to a seventh modified example viewed from below. Fig. 33 is an exploded perspective view of a deformation detection sensor 1j according to the fourth embodiment. Fig. 34 is an exploded perspective view of a deformation detection sensor 1k according to an eighth modified example.

[0014] [First Embodiment] (Configuration of Deformation Detection Sensor 1) The configuration of a deformation detection sensor 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 deformation detection sensor 1 according to the first embodiment. FIG. 2 is a perspective view of the deformation detection sensor 1 according to the first embodiment. FIG. 3 is a cross-sectional view of the deformation detection sensor 1 according to the first embodiment, viewed from the front, when the bending angle θ of the flexible substrate 2 according to the first embodiment is 0 degrees. FIG. 4 is a cross-sectional view of the deformation detection sensor 1 according to the first embodiment, viewed from the front, when the bending angle θ of the flexible substrate 2 according to the first embodiment is 180 degrees. FIG. 5 is a cross-sectional view of the first sensor 3 according to the first embodiment, viewed from the front. FIG. 6 is a plan view of the first sensor 3 according to the first embodiment, viewed from below. FIG. 7 is a plan view of the deformation detection sensor 1 according to the first embodiment, viewed from below. FIG. 8 is a plan view of the deformation detection sensor 1 according to the first embodiment, viewed from below.

[0015] The deformation detection sensor 1 is used in, for example, a foldable smartphone. As shown in Fig. 1, the deformation detection sensor 1 includes a flexible substrate 2, a first sensor 3, a first deformation-inhibiting member 4, a second deformation-inhibiting member 5, and an arithmetic circuit (not shown).

[0016] As shown in Figure 2, the flexible substrate 2 has a rectangular sheet shape when viewed in the vertical direction. Therefore, the flexible substrate 2 has a substrate upper main surface US2 and a substrate lower main surface LS2 that are aligned in the vertical direction. The substrate upper main surface US2 is located on the substrate lower main surface LS2. Furthermore, the flexible substrate 2 has long sides extending in the left-right direction and short sides extending in the front-to-back direction when viewed in the vertical direction.

[0017] The flexible substrate 2 has flexibility. Therefore, as shown in Figures 3 and 4, the flexible substrate 2 is bent at a first bending line L1 extending in the front-to-rear direction. As shown in Figure 3, the flexible substrate 2 has non-curved sections NCS1, NCS3, and a curved section CS2. The non-curved sections NCS1, NCS3 are sections that do not curve when the flexible substrate 2 is bent at the first bending line L1. The curved section CS2 is a section that curves when the flexible substrate 2 is bent at the first bending line L1. The non-curved section NCS1, the curved section CS2, and the non-curved section NCS3 are arranged in this order from left to right when the flexible substrate 2 is not bent.

[0018] As shown in Fig. 3, the flexible substrate 2 includes a first portion P1 and a second portion P2. The first portion P1 is located in the non-curved section NCS1. The second portion P2 is located in the non-curved section NCS3. When the flexible substrate 2 is bent, the second portion P2 can rotate relative to the first portion P1, as shown in Fig. 4. The flexible substrate 2 is, for example, a display. The flexible substrate 2 is realized by, for example, a single organic EL display.

[0019] The first sensor 3 outputs a first detection signal SigD1 corresponding to the deformation of the curved section CS2 of the flexible substrate 2. As shown in FIG. 1 , the first sensor 3 is provided on the substrate upper principal surface US2 of the flexible substrate 2. More specifically, as shown in FIG. 5 , the first sensor 3 has a first upper principal surface US3 and a first lower principal surface LS3 aligned in the vertical direction. The first upper principal surface US3 is located above the first lower principal surface LS3. As shown in FIG. 1 , the first sensor 3 is provided on the substrate upper principal surface US2 of the flexible substrate 2 so that the first lower principal surface LS3 is in contact with the substrate upper principal surface US2 of the flexible substrate 2.

[0020] 6, the first sensor 3 has a rectangular shape with long sides extending in the left-right direction and short sides extending in the front-rear direction when viewed in the up-down direction. As shown in FIG. 1, the first sensor 3 includes a first piezoelectric film 31, a first upper electrode 32, and a first lower electrode 33.

[0021] The first piezoelectric film 31 has a sheet shape. Therefore, as shown in Fig. 5, the first piezoelectric film 31 has a first piezoelectric film upper principal surface US31 and a first piezoelectric film lower principal surface LS31 aligned in the vertical direction. The first piezoelectric film upper principal surface US31 is located above the first piezoelectric film lower principal surface LS31.

[0022] As shown in FIG. 6, the first piezoelectric film 31 has a rectangular shape with long sides extending in the left-right direction and short sides extending in the front-rear direction when viewed in the up-down direction.

[0023] The first piezoelectric film 31 generates an electric charge according to the amount of deformation of the first piezoelectric film 31. In this embodiment, the first piezoelectric film 31 is a PLA film. The first piezoelectric film 31 will be described in more detail below.

[0024] The first piezoelectric film 31 has a characteristic that the polarity of the electric charge generated when the first piezoelectric film 31 is stretched in the left-right direction of the piezoelectric film is opposite to the polarity of the electric charge generated when the first piezoelectric film 31 is stretched in the front-back direction of the piezoelectric film. Specifically, the first piezoelectric film 31 is a film formed from a chiral polymer. An example of a chiral polymer is polylactic acid (PLA), particularly poly-L-lactic acid (PLLA). PLLA, which is made of a chiral polymer, has a helical main chain structure. PLLA has piezoelectricity in which the molecules are oriented when uniaxially stretched. The first piezoelectric film 31 has a piezoelectric constant of d14.

[0025] Here, the angle formed by the uniaxial stretching direction OD of the first piezoelectric film 31 is defined as a negative angle when viewed in the vertical direction of the piezoelectric film (vertical direction), and a positive angle when viewed counterclockwise when viewed in the vertical direction of the piezoelectric film (vertical direction). As shown in FIG. 6 , the uniaxial stretching direction OD of the first piezoelectric film 31 forms a 45-degree angle with the left-right direction of the piezoelectric film (horizontal direction) when viewed in the vertical direction of the piezoelectric film, and a −45-degree angle with the front-to-back direction when viewed in the vertical direction of the piezoelectric film (vertical direction). Therefore, as shown in FIG. 6 , when the flexible substrate 2 is not bent, the uniaxial stretching direction OD of the first piezoelectric film 31 forms a −45-degree angle with the first bending line L1 when viewed in the vertical direction. Furthermore, this −45-degree angle includes, for example, an angle of approximately −45 degrees ±10 degrees. Furthermore, this -45 degrees includes angles of approximately 135 degrees ±10 degrees (approximately -225 degrees ±10 degrees). As a result, the first piezoelectric film 31 generates electric charge when the first piezoelectric film 31 is stretched in the left-right direction or the front-back direction of the piezoelectric film.

[0026] The polarity of the charge generated by the first piezoelectric film 31 when it is stretched in the left-right direction differs from the polarity of the charge generated by the first piezoelectric film 31 when it is stretched in the front-rear direction. For example, the first piezoelectric film 31 generates a negative charge when it is stretched in the left-right direction. For example, the first piezoelectric film 31 generates a positive charge when it is stretched in the front-rear direction. The magnitude of the charge depends on the amount of deformation of the first piezoelectric film 31 due to stretching or compression. More precisely, the magnitude of the charge is proportional to the differential value of the amount of deformation of the first piezoelectric film 31 due to stretching or compression.

[0027] The first upper electrode 32 is a ground electrode. The first upper electrode 32 has upper and lower principal surfaces aligned in the vertical direction. The first upper electrode 32 is electrically connected to the ground potential. As shown in FIG. 5 , the first upper electrode 32 is provided on the first piezoelectric film upper principal surface US31 of the first piezoelectric film 31. As shown in FIG. 6 , the first upper electrode 32 covers the entire first piezoelectric film upper principal surface US31 of the first piezoelectric film 31. The first upper electrode 32 includes an adhesive layer (not shown). The adhesive layer fixes the first upper electrode 32 to the first piezoelectric film upper principal surface US31 of the first piezoelectric film 31. The upper principal surface of the first upper electrode 32 is the first upper principal surface US3 of the first sensor 3.

[0028] The first lower electrode 33 is a first signal electrode. The first lower electrode 33 has upper and lower main surfaces aligned in the vertical direction. A first detection signal SigD1 corresponding to the deformation of the curved section CS2 of the flexible substrate 2 is output from the first lower electrode 33. As shown in FIG. 5 , the first lower electrode 33 is provided on the first piezoelectric film lower main surface LS31 of the first piezoelectric film 31. As shown in FIG. 6 , the first lower electrode 33 covers the entire first piezoelectric film lower main surface LS31 of the first piezoelectric film 31. The first lower electrode 33 includes an adhesive layer (not shown). The adhesive layer fixes the first lower electrode 33 to the first piezoelectric film lower main surface LS31 of the first piezoelectric film 31. The lower main surface of the first lower electrode 33 is the first lower main surface LS3 of the first sensor 3.

[0029] 3, the first sensor 3 is provided on the upper main surface US2 of the flexible substrate 2 so as to straddle the first bending line L1 when viewed in the vertical direction. That is, the first sensor 3 has a portion located to the left of the first bending line L1 and a portion located to the right of the first bending line L1.

[0030] As shown in Fig. 1, the first deformation inhibiting member 4 and the second deformation inhibiting member 5 are arranged in this order from left to right with a gap between them. Furthermore, as shown in Fig. 3, the first deformation inhibiting member 4 is located to the left of the first bending line L1. The second deformation inhibiting member 5 is located to the right of the first bending line L1. Therefore, as shown in Fig. 1, the first deformation inhibiting member 4 and the second deformation inhibiting member 5 do not overlap each other when viewed in the vertical direction.

[0031] 1 , the first deformation inhibiting member 4 has a rectangular shape with short sides extending in the left-right direction and long sides extending in the front-rear direction when viewed in the up-down direction. The material of the first deformation inhibiting member 4 is, for example, metal, resin, ceramic, or glass. The first deformation inhibiting member 4 is harder than the first piezoelectric film 31 of the first sensor 3. For example, the Young's modulus of the first deformation inhibiting member 4 is greater than the Young's modulus of the first piezoelectric film 31 of the first sensor 3.

[0032] 1, the first deformation-preventing member 4 is provided on the first upper principal surface US3 of the first sensor 3. Therefore, as shown in Fig. 7, the first deformation-preventing member 4 has a first region A1 that overlaps with the first piezoelectric film 31 when viewed in the up-down direction. The first region A1 is located to the left of the first bending line L1.

[0033] In this embodiment, as shown in Fig. 2 , the first deformation inhibiting member 4 covers the entire left side surface of the first sensor 3, the left end of the front side surface, and the left end of the rear side surface. As a result, the first deformation inhibiting member 4 contacts the substrate upper main surface US2 of the flexible substrate 2 in front of the first sensor 3, the left front side of the first sensor 3, the left rear side of the first sensor 3, and the rear side of the first sensor 3, as viewed in the vertical direction. That is, as shown in Fig. 7 , the first deformation inhibiting member 4 contacts the substrate upper main surface US2 of the flexible substrate 2 and has a third region A3 that does not overlap with the first piezoelectric film 31 of the first sensor 3, as viewed in the vertical direction. The first deformation inhibiting member 4 is fixed to the substrate upper main surface US2 in the third region A3.

[0034] 1 , the second deformation inhibiting member 5 has a rectangular shape with short sides extending in the left-right direction and long sides extending in the front-rear direction when viewed in the up-down direction. The second deformation inhibiting member 5 is made of a material such as metal, resin, ceramic, or glass. The second deformation inhibiting member 5 is harder than the first piezoelectric film 31 of the first sensor 3. For example, the Young's modulus of the second deformation inhibiting member 5 is greater than the Young's modulus of the first piezoelectric film 31 of the first sensor 3.

[0035] 1, the second deformation-preventing member 5 is provided on the first upper principal surface US3 of the first sensor 3. Therefore, as shown in Fig. 7, the second deformation-preventing member 5 has a second region A2 that overlaps with the first piezoelectric film 31 when viewed in the up-down direction. In this embodiment, the second region A2 is located to the right of the first bending line L1.

[0036] In this embodiment, as shown in Fig. 2 , the second deformation inhibiting member 5 covers the entire right side surface of the first sensor 3, the right end of the front side surface, and the right end of the rear side surface. As a result, the second deformation inhibiting member 5 contacts the substrate upper main surface US2 of the flexible substrate 2 in front of the first sensor 3, the right front side of the first sensor 3, the right side of the first sensor 3, the right rear side of the first sensor 3, and the rear side of the first sensor 3, as viewed in the vertical direction. That is, as shown in Fig. 7 , the second deformation inhibiting member 5 contacts the substrate upper main surface US2 of the flexible substrate 2 and has a fourth region A4 that does not overlap with the first piezoelectric film 31 of the first sensor 3 in the vertical direction. The second deformation inhibiting member 5 is fixed to the substrate upper main surface US2 in the fourth region A4.

[0037] As shown in FIG. 7 , the first region A1 and the second region A2 are arranged side by side with a gap between them in the left-right direction. More specifically, the first region A1 is located to the left of the second region A2. Furthermore, the first region A1 and the second region A2 do not contact each other when viewed in the up-down direction when the flexible substrate 2 is not bent. Therefore, the first region A1 and the second region A2 do not overlap each other when viewed in the up-down direction. Furthermore, the first piezoelectric film 31 has a tenth region A10 that does not overlap with the first deformation-inhibiting member 4 and the second deformation-inhibiting member 5 when viewed in the up-down direction.

[0038] Here, the horizontal distance D1 between the first region A1 and the second region A2 is defined when the flexible substrate 2 is not bent. As shown in FIG. 7 , the horizontal distance D1 between the first region A1 and the second region A2 is the shortest horizontal distance between the portions where the first region A1 and the second region A2 do not contact each other. In this embodiment, the right end of the first region A1 coincides with a portion of the right edge of the first deformation inhibiting member 4. The right edge of the first deformation inhibiting member 4 extends in the front-to-rear direction. Furthermore, the left end of the second region A2 coincides with a portion of the left edge of the second deformation inhibiting member 5. The left edge of the second deformation inhibiting member 5 extends in the front-to-rear direction. Therefore, the horizontal distance D1 between the first region A1 and the second region A2 is the distance between the right edge of the first deformation inhibiting member 4 and the left edge of the second deformation inhibiting member 5 when viewed in the vertical direction.

[0039] As shown in FIG. 7, the left-right distance D1 between the first region A1 and the second region A2 is shorter than the left-right length DLR31 of the first piezoelectric film 31 when the flexible substrate 2 is not bent.

[0040] Here, when the flexible substrate 2 is not bent, the left-right position at which the first region A1 exists is defined as a first position PO1, as shown in Fig. 8. Also, when the flexible substrate 2 is not bent, the left-right position at which the second region A2 exists is defined as a second position PO2.

[0041] 8, the length DFB4 in the front-rear direction of the first deformation-inhibiting member 4 at the first position PO1 is longer than the length DFB311 in the front-rear direction of the first piezoelectric film 31 at the first position PO1 when the flexible base material 2 is not bent. Note that it is sufficient if there is a first position PO1 at which the length DFB4 in the front-rear direction of the first deformation-inhibiting member 4 at the first position PO1 is longer than the length DFB311 in the front-rear direction of the first piezoelectric film 31 at the first position PO1 when the flexible base material 2 is not bent.

[0042] 8, the length DFB5 in the front-to-rear direction of the second deformation-inhibiting member 5 at the second position PO2 is longer than the length DFB312 in the front-to-rear direction of the first piezoelectric film 31 at the second position PO2 when the flexible substrate 2 is not bent. Note that it is sufficient if there is a first position PO1 at which the maximum value of the length DFB5 in the front-to-rear direction of the second deformation-inhibiting member 5 at the second position PO2 is longer than the length DFB312 in the front-to-rear direction of the first piezoelectric film 31 at the second position PO2 when the flexible substrate 2 is not bent.

[0043] The arithmetic circuit receives the first detection signal SigD1 output by the first sensor 3. The arithmetic circuit calculates a first integral value IV1 by time-integrating the first detection signal SigD1. The arithmetic circuit also calculates the bending angle θ of the flexible substrate 2 by correlating the first integral value IV1 with the bending angle θ of the flexible substrate 2.

[0044] The method of associating the first integral value IV1 with the bending angle θ of the flexible substrate 2 is, for example, such that when the first integral value IV1 is 0, the bending angle θ of the flexible substrate 2 is 0, and when the first integral value IV1 is −180, the bending angle θ of the flexible substrate 2 is 180 degrees. Also, for example, when −180<first integral value IV1<0, the absolute value of the first integral value IV1 is taken as the bending angle θ (degrees) of the flexible substrate 2. Note that this method of associating the first integral value IV1 with the bending angle θ of the flexible substrate 2 is merely an example, and other methods may be used.

[0045] When the value of the first detection signal SigD1 becomes discontinuous, the arithmetic circuit sets the bending angle θ of the flexible substrate 2 to θa. θa is the bending angle θ of the flexible substrate 2 at which the first deformation-inhibiting member 4 and the second deformation-inhibiting member 5 begin to contact each other when the bending angle θ of the flexible substrate 2 is changed from 0 degrees to 180 degrees. At this time, the arithmetic circuit corrects the first integral value IV1 to a value associated with θa.

[0046] (Configuration of Electronic Device 100) The configuration of the electronic device 100 according to the first embodiment of the present invention will be described below with reference to the drawings. Fig. 9 is an exploded perspective view of the electronic device 100 according to the first embodiment. Fig. 10 is a cross-sectional view of the electronic device 100 according to the first embodiment, viewed from the front, when the bending angle θ of the flexible substrate 2 is 0 degrees. Fig. 11 is a cross-sectional view of the electronic device 100 according to the first embodiment, viewed from the front, when the bending angle θ of the flexible substrate 2 is 180 degrees.

[0047] 9, the electronic device 100 includes a deformation detection sensor 1, a flexible substrate 2, a first housing 6, and a second housing 7. The electronic device 100 is, for example, a foldable smartphone.

[0048] As shown in Fig. 1, the first housing 6 is provided on the lower main surface LS2 of the flexible substrate 2. As shown in Fig. 9, the first housing 6 is a box. The first housing 6 has a rectangular parallelepiped shape.

[0049] As shown in Fig. 1, the second housing 7 is provided on the lower main surface LS2 of the flexible substrate 2. As shown in Fig. 9, the second housing 7 is a box. The second housing 7 has a rectangular parallelepiped shape.

[0050] 10 , the first housing 6 is located in the non-curved section NCS1 of the flexible substrate 2 when viewed in the vertical direction. The second housing 7 is located in the non-curved section NCS3 of the flexible substrate 2 when viewed in the vertical direction. The second housing 7 can rotate with respect to the first housing 6 as shown in FIG. 11 by bending the flexible substrate 2.

[0051] As shown in Fig. 10 , the first housing 6 is located to the left of the first bending line L1. The second housing 7 is located to the right of the first bending line L1. That is, as shown in Fig. 9 , the first bending line L1 is located between the first housing 6 and the second housing 7 when viewed in the vertical direction when the flexible base material 2 is not bent. Furthermore, the first housing 6 and the second housing 7 do not overlap each other when viewed in the vertical direction when the flexible base material 2 is not bent.

[0052] The deformation detection sensor 1 has a structure that can accurately detect the bending angle θ of the flexible substrate 2. This structure will be described below. FIG. 12 is a cross-sectional view of the deformation detection sensor 10 according to the comparative example when the bending angle θ of the flexible substrate 2 according to the comparative example is 0 degrees, as viewed from the front. FIG. 13 is a cross-sectional view of the deformation detection sensor 10 according to the comparative example when the bending angle θ of the flexible substrate 2 according to the comparative example is 180 degrees, as viewed from the front. FIG. 14 is an example of the first detection signal SigD1 when the bending angle θ of the flexible substrate 2 according to the comparative example is changed from 0 degrees to 180 degrees. In FIG. 14, the horizontal axis represents the bending angle θ of the flexible substrate 2. The vertical axis represents the value of the first detection signal SigD1. FIG. 15 is an example of the first integral value IV1 when the bending angle θ of the flexible substrate 2 according to the comparative example is changed from 0 degrees to 180 degrees. In FIG. 15, the horizontal axis represents time t. The vertical axis represents the first integral value IV1. FIG. 16 shows an example of the first integral value IV1 when noise N is superimposed on the first detection signal SigD1 when the bending angle θ of the flexible substrate 2 according to the comparative example is changed from 0 degrees to 180 degrees. In FIG. 16 , the horizontal axis represents the bending angle θ of the flexible substrate 2 or time t. The vertical axis represents the value of the first detection signal SigD1, the value of the noise N, and the first integral value IV1. FIG. 17 shows an example of the first detection signal SigD1 when the bending angle θ of the flexible substrate 2 according to the first embodiment is changed from 0 degrees to 180 degrees. In FIG. 17 , the horizontal axis represents the bending angle θ of the flexible substrate 2. The vertical axis represents the value of the first detection signal SigD1. FIG. 18 is a cross-sectional view of the deformation detection sensor 1 and the flexible substrate 2 according to the first embodiment, viewed from the front, when the bending angle θ of the flexible substrate 2 is θa. Fig. 19 shows an example of the first integral value IV1 when the bending angle θ of the flexible substrate 2 according to the first embodiment is changed from 0 degrees to 180 degrees. In Fig. 19, the horizontal axis represents time t. The vertical axis represents the first integral value IV1. Fig. 20 shows an example of the first integral value IV1 when noise N is superimposed on the first detection signal SigD1 when the bending angle θ of the flexible substrate 2 according to the first embodiment is changed from 0 degrees to 180 degrees. In Fig. 20, the horizontal axis represents the bending angle θ of the flexible substrate 2 or the time t. The vertical axis represents the value of the first detection signal SigD1, the value of the noise N, and the first integral value IV1.

[0053] 12, the deformation detection sensor 10 according to the comparative example differs from the deformation detection sensor 1 in that it does not include the first deformation inhibiting member 4 and the second deformation inhibiting member 5. The deformation detection sensor 10 according to the comparative example is otherwise the same as the deformation detection sensor 1, and therefore a description thereof will be omitted.

[0054] In the deformation detection sensor 10 according to the comparative example, when the bending angle θ of the flexible substrate 2 is changed from 0 degrees ( FIG. 12 ) to 180 degrees ( FIG. 13 ) at a constant angular velocity, the value of the first detection signal SigD1 output by the first sensor 3 becomes a constant negative value, as shown in FIG. 14 . The reason why the first detection signal SigD1 is negative is that when the bending angle θ of the flexible substrate 2 is increased, the first piezoelectric film 31 generates a negative charge as the first piezoelectric film 31 is stretched in the left-right direction of the piezoelectric film. The reason why the value of the first detection signal SigD1 is a constant value is because the magnitude of the charge generated by the first piezoelectric film 31 is proportional to the differential value of the deformation amount of the first piezoelectric film 31 due to stretching, and because the bending angle θ of the flexible substrate 2 is changed at a constant angular velocity.

[0055] In the deformation detection sensor 10 according to the comparative example, the arithmetic circuit calculates a first integral value IV1 by time-integrating the first detection signal SigD1, as shown in Fig. 15. The arithmetic circuit also calculates the bending angle θ of the flexible substrate 2 by associating the first integral value IV1 with the bending angle θ of the flexible substrate 2.

[0056] Next, a problem with the deformation detection sensor 10 according to the comparative example will be described. The deformation detection sensor 10 according to the comparative example has difficulty in accurately detecting the bending angle θ of the flexible substrate 2. The deformation detection sensor 10 according to the comparative example detects the bending angle θ of the flexible substrate 2 by correlating the first integral value IV1 calculated by the arithmetic circuit with the bending angle θ of the flexible substrate 2. Therefore, an error occurs between the actual bending angle θ of the flexible substrate 2 and the detected value of the bending angle θ of the flexible substrate 2 due to noise N entering the deformation detection sensor 10 according to the comparative example during deformation of the flexible substrate 2 and repeated deformation of the flexible substrate 2, etc.

[0057] 16 , when noise N is superimposed on the first detection signal SigD1, an error occurs between the actual bending angle θ of the flexible substrate 2 and the detected value of the bending angle θ of the flexible substrate 2. In the example shown in FIG. 16 , when the angle (assumed to be θ1) is smaller than 180 degrees, the first integral value IV1 becomes −180, and the arithmetic circuit calculates the bending angle θ of the flexible substrate 2 as 180 degrees, even though the actual bending angle θ of the flexible substrate 2 is θ1. Therefore, it is difficult for the deformation detection sensor 10 according to the comparative example to accurately detect the bending angle θ of the flexible substrate 2.

[0058] On the other hand, in the deformation detection sensor 1, when the bending angle θ of the flexible substrate 2 is changed from 0 degrees (FIG. 3) to 180 degrees (FIG. 4) at a constant angular velocity, the value of the first detection signal SigD1 output by the first sensor 3 has a discontinuous portion, as shown in FIG. 17. The reason for this will be explained below.

[0059] In the deformation detection sensor 1, when the bending angle θ of the flexible substrate 2 is changed from 0 degrees to 180 degrees at a constant angular velocity, the first deformation inhibiting member 4 and the second deformation inhibiting member 5 do not come into contact with each other in the range of 0 degrees≦θ<θa. That is, the value of the first detection signal SigD1 output by the first sensor 3 becomes a constant negative value in the range of 0 degrees≦θ<θa, as shown in FIG.

[0060] When the bending angle θ of the flexible substrate 2 becomes θa (0 degrees < θa < 180 degrees), the first deformation inhibiting member 4 and the second deformation inhibiting member 5 come into contact with each other, as shown in FIG. 18 . In the range of θa≦θ≦180 degrees, the first deformation inhibiting member 4 and the second deformation inhibiting member 5 come into contact with each other. At this time, the first deformation inhibiting member 4 and the second deformation inhibiting member 5 prevent the first piezoelectric film 31 from stretching in the left-right direction of the piezoelectric film. As a result, the absolute value of the value of the first detection signal SigD1 in the range of θa≦θ≦180 degrees is smaller than the absolute value of the value of the first detection signal SigD1 in the range of 0 degrees≦θ<θa, as shown in FIG. 17 . Note that the first piezoelectric film 31 stretches in the left-right direction of the piezoelectric film even in the range of θa≦θ≦180 degrees. Therefore, when the bending angle θ of the flexible substrate 2 is changed from θa ( FIG. 18 ) to 180 degrees ( FIG. 4 ) at a constant angular velocity, the first piezoelectric film 31 generates a negative charge. As a result, the value of the first detection signal SigD1 output by the first sensor 3 becomes a constant negative value in the range of θa≦θ≦180 degrees, as shown in FIG.

[0061] As shown in Fig. 19, the arithmetic circuit calculates a first integral value IV1 by time-integrating the first detection signal SigD1. When the value of the first detection signal SigD1 becomes discontinuous (time t1 in Fig. 19), the arithmetic circuit sets the bending angle θ of the flexible substrate 2 to θa. At this time, the arithmetic circuit corrects the first integral value IV1 to -θa.

[0062] For example, as shown in FIG. 20 , if noise N is superimposed on the first detection signal SigD1, an error occurs between the actual bending angle θ of the flexible substrate 2 and the detected value of the bending angle θ of the flexible substrate 2. However, when the value of the first detection signal SigD1 becomes discontinuous (time t1 in FIG. 20 ), the arithmetic circuit sets the bending angle θ of the flexible substrate 2 to θa. At this time, the arithmetic circuit corrects the first integral value IV1 to −θa. Therefore, the value of the first detection signal SigD1 in the range of θa≦θ≦180 degrees is not affected by the superimposed noise N in the range of 0 degrees≦θ<θa. As a result, the deformation detection sensor 1 can accurately detect the bending angle θ of the flexible substrate 2.

[0063] [Effect] The deformation detection sensor 1 can accurately detect the bending angle of the substrate. More specifically, the first deformation inhibiting member 4 is provided on the first upper main surface US3 of the first sensor 3. The second deformation inhibiting member 5 is provided on the first upper main surface US3 of the first sensor 3. That is, the first deformation inhibiting member 4 and the second deformation inhibiting member 5 are provided on the same surface of the first sensor 3. The first deformation inhibiting member 4 is provided on the first upper main surface US3 of the first sensor 3, thereby having a first region A1 that overlaps with the first piezoelectric film 31. Similarly, the second deformation inhibiting member 5 is provided on the first upper main surface US3 of the first sensor 3, thereby having a second region A2 that overlaps with the first piezoelectric film 31. The first region A1 and the second region A2 do not contact each other when viewed in the vertical direction when the flexible substrate 2 is not bent. As a result, the first bending line L1 can be positioned between the first region A1 and the second region A2 when viewed in the vertical direction. The flexible substrate 2 is bent at the first bending line L1. At this time, the first deformation inhibiting member 4 and the second deformation inhibiting member 5 come into contact with each other. The value of the first detection signal SigD1 output by the first sensor 3 becomes discontinuous when the bending angle θ of the flexible substrate 2 is θa. θa is the bending angle θ of the flexible substrate 2 at which the first deformation inhibiting member 4 and the second deformation inhibiting member 5 begin to come into contact with each other when the bending angle θ of the flexible substrate 2 is changed from 0 degrees to 180 degrees. Therefore, when the value of the first detection signal SigD1 becomes discontinuous, the arithmetic circuit can set the bending angle θ of the flexible substrate 2 to θa. At this time, the arithmetic circuit can correct the first integral value IV1 to a value corresponding to θa. As a result, the deformation detection sensor 1 can prevent the value of the first detection signal SigD1 in the range of θa≦θ≦180 degrees from being affected by the noise N superimposed in the range of 0 degrees≦θ<θa. Therefore, the deformation detection sensor 1 can accurately detect the bending angle θ of the flexible substrate 2. As a result, the deformation detection sensor 1 can accurately detect the bending angle of the substrate.

[0064] The deformation detection sensor 1 can suppress a decrease in reliability of the deformation detection sensor 1 due to misalignment of the first deformation inhibiting member 4 or the second deformation inhibiting member 5. More specifically, the first deformation inhibiting member 4 has a third region A3 that contacts the substrate upper main surface US2 of the flexible substrate 2 and does not overlap with the first piezoelectric film 31 when viewed in the vertical direction. This allows the first deformation inhibiting member 4 to be fixed to the substrate upper main surface US2 of the flexible substrate 2 in the third region A3. Therefore, the deformation detection sensor 1 can suppress misalignment of the first deformation inhibiting member 4. Furthermore, the second deformation inhibiting member 5 has a fourth region A4 that contacts the substrate upper main surface US2 of the flexible substrate 2 and does not overlap with the first piezoelectric film 31 when viewed in the vertical direction. This allows the second deformation inhibiting member 5 to be fixed to the substrate upper main surface US2 of the flexible substrate 2 in the fourth region A4. Therefore, the deformation detection sensor 1 can suppress misalignment of the second deformation inhibiting member 5. As a result, according to the deformation detection sensor 1, it is possible to suppress a decrease in reliability of the deformation detection sensor 1 due to misalignment of the first deformation inhibiting member 4 or the second deformation inhibiting member 5.

[0065] The deformation detection sensor 1 can prevent the first piezoelectric film 31 from peeling off from the flexible substrate 2 as the flexible substrate 2 deforms. More specifically, the first sensor 3 is provided on the substrate upper main surface US2 of the flexible substrate 2. The first deformation inhibiting member 4 is provided on the first upper main surface US3 of the first sensor 3. The second deformation inhibiting member 5 is provided on the first upper main surface US3 of the first sensor 3. The deformation of the first sensor 3 is inhibited by the first deformation inhibiting member 4 and the second deformation inhibiting member 5. As a result, the deformation detection sensor 1 can prevent the first piezoelectric film 31 from peeling off from the flexible substrate 2 as the flexible substrate 2 deforms.

[0066] The deformation detection sensor 1 can further prevent the first piezoelectric film 31 from peeling off from the flexible substrate 2 as the flexible substrate 2 deforms. More specifically, the left-right distance D1 between the first region A1 and the second region A2 is shorter than the left-right length of the first piezoelectric film 31 when the flexible substrate 2 is not bent. This reduces the area of ​​the portion of the first piezoelectric film 31 that is exposed from the first deformation inhibiting member 4 or the second deformation inhibiting member 5 when viewed in the up-down direction. As a result, the deformation detection sensor 1 can further prevent the first piezoelectric film 31 from peeling off from the flexible substrate 2 as the flexible substrate 2 deforms.

[0067] The deformation detection sensor 1 can further prevent the first piezoelectric film 31 from peeling off from the flexible substrate 2 due to deformation of the flexible substrate 2. More specifically, there is a first position PO1 (the left-right position where the first region A1 exists) where the front-rear length of the first deformation-inhibiting member 4 at the first position PO1 is longer than the front-rear length of the first piezoelectric film 31 at the first position PO1 when the flexible substrate 2 is not bent. This allows the portion of the first deformation-inhibiting member 4 located at this first position PO1 to be fixed to the substrate upper main surface US2 of the flexible substrate 2 in front of or behind the first piezoelectric film 31 when viewed in the up-down direction. This allows the first piezoelectric film 31 to be more firmly fixed to the substrate upper main surface US2 of the flexible substrate 2. Furthermore, there exists a second position PO2 (a left-right position where the second region A2 exists) where the front-rear length of the second deformation-inhibiting member 5 at the second position PO2 is longer than the front-rear length of the first piezoelectric film 31 at the second position PO2 when the flexible substrate 2 is not bent. This allows the portion of the second deformation-inhibiting member 5 located at this second position PO2 to be fixed to the substrate upper main surface US2 of the flexible substrate 2 in front of or behind the first piezoelectric film 31 when viewed in the up-down direction. Therefore, the first piezoelectric film 31 can be more firmly fixed to the substrate upper main surface US2 of the flexible substrate 2. As a result, the deformation detection sensor 1 can prevent the first piezoelectric film 31 from peeling off from the flexible substrate 2 due to deformation of the flexible substrate 2.

[0068] The deformation detection sensor 1 can detect the bending angle of the substrate with higher accuracy. More specifically, the first upper electrode 32 of the first sensor 3 is provided on the first piezoelectric film upper main surface US31 of the first piezoelectric film 31. The first upper electrode 32 is a ground electrode electrically connected to the ground potential. Therefore, the first upper electrode 32 serves as a shield against noise that enters from outside the deformation detection sensor 1. This makes it difficult for noise to enter from outside the deformation detection sensor 1. As a result, the deformation detection sensor 1 can detect the bending angle of the substrate with higher accuracy.

[0069] [First Modification] A deformation detection sensor 1a according to a first modification of the present invention will be described below with reference to the drawings. Fig. 21 is an exploded perspective view of the deformation detection sensor 1a according to the first modification. Note that, with regard to the deformation detection sensor 1a according to the first modification, only the parts that are different from the deformation detection sensor 1 according to the first embodiment will be described, and the rest will be omitted.

[0070] The deformation detection sensor 1a differs from the deformation detection sensor 1 in that the first deformation inhibition member 4 is provided on the first lower main surface LS3 of the first sensor 3, and the second deformation inhibition member 5 is provided on the first lower main surface LS3 of the first sensor 3.

[0071] As shown in Figure 21, the first sensor 3 is provided on the upper main surface US2 of the flexible substrate 2 so that the first lower main surface LS3 contacts the upper main surface of the first deformation inhibition member 4 and the upper main surface of the second deformation inhibition member 5.

[0072] The deformation detection sensor 1a as described above also achieves the same effect as the deformation detection sensor 1. In this way, the second deformation inhibiting member 5 may be provided on the first upper principal surface US3 or the first lower principal surface LS3 of the first sensor 3, on which the first deformation inhibiting member 4 is provided.

[0073] [Second Modification] A deformation detection sensor 1b according to a second modification of the present invention will be described below with reference to the drawings. Fig. 22 is a plan view of the deformation detection sensor 1b according to the second modification as viewed from below. Note that with regard to the deformation detection sensor 1b according to the second modification, only the differences from the deformation detection sensor 1 according to the first embodiment will be described, and the rest will be omitted.

[0074] The deformation detection sensor 1a differs from the deformation detection sensor 1 in that the deformation detection sensor 1a has a fifth region A5 where the first region A1 of the first deformation-inhibiting member 4 and the second region A2 of the second deformation-inhibiting member 5 overlap each other.

[0075] As shown in FIG. 22 , the first region A1 and the second region A2 overlap each other in the fifth region A5. The first region A1 and the second region A2 contact each other in the fifth region A5. The first region A1 and the second region A2 have a third portion P3 that does not contact each other when viewed in the vertical direction when the flexible substrate 2 is not bent. In this modification, the third portion P3 is located in front of the fifth region A5. The first deformation-inhibiting member 4 and the second deformation-inhibiting member 5 are flexible in the fifth region A5.

[0076] The deformation detection sensor 1b as described above also achieves the same effect as the deformation detection sensor 1. In this way, the first region A1 and the second region A2 only need to have the third portion P3 that does not contact each other when viewed in the up-down direction when the flexible base material 2 is not bent.

[0077] [Third Modification] A deformation detection sensor 1c according to a third modification of the present invention will be described below with reference to the drawings. Fig. 23 is a plan view of the deformation detection sensor 1c according to the third modification, viewed from below. Note that, with regard to the deformation detection sensor 1c according to the third modification, only the differences from the deformation detection sensor 1b according to the second modification will be described, and the rest will be omitted.

[0078] The deformation detection sensor 1 c differs from the deformation detection sensor 1 b in that the first deformation inhibiting member 4 and the second deformation inhibiting member 5 are included in a single member 8 .

[0079] The left portion of the member 8 and the right portion of the member 8 are connected in a fifth region A5 as shown in Fig. 23. The member 8 is flexible in the fifth region A5.

[0080] The deformation detection sensor 1c as described above also has the same effect as the deformation detection sensor 1b.

[0081] Second Embodiment A deformation detection sensor 1d according to a second embodiment of the present invention will be described below with reference to the drawings. FIG. 24 is an exploded perspective view of the deformation detection sensor 1d according to the second embodiment. FIG. 25 is an exploded perspective view of an electronic device 100d according to the second embodiment. FIG. 26 shows an example of the second integral value IV2 obtained when noise N is superimposed on the second detection signal SigD2 as the bending angle θ of the flexible substrate 2 according to the second embodiment is changed from 0 degrees to 180 degrees. In FIG. 26, the horizontal axis represents the bending angle θ of the flexible substrate 2 or the time t. The vertical axis represents the value of the second detection signal SigD2, the value of the noise N, and the second integral value IV2. Note that, with regard to the deformation detection sensor 1d according to the second embodiment, only differences from the deformation detection sensor 1 according to the first embodiment will be described, and the rest will be omitted.

[0082] The deformation detection sensor 1d differs from the deformation detection sensor 1b in that it further includes a second sensor 11.

[0083] The second sensor 11 outputs a second detection signal SigD2 corresponding to the deformation of the curved section CS2 of the flexible substrate 2. As shown in FIG. 24 , the second sensor 11 includes a second piezoelectric film 111, a second upper electrode 112, and a second lower electrode 113. The second sensor 11 is provided on the substrate upper principal surface US2 of the flexible substrate 2. More specifically, the second sensor 11 also has a second upper principal surface US11 and a second lower principal surface LS11 aligned in the vertical direction. The second upper principal surface US11 is located above the second lower principal surface LS11. The second sensor 11 is provided on the substrate upper principal surface US2 of the flexible substrate 2 so that the second lower principal surface LS11 is in contact with the substrate upper principal surface US2 of the flexible substrate 2.

[0084] As shown in FIG. 24, the second sensor 11 has a rectangular shape with long sides extending in the left-right direction and short sides extending in the front-rear direction when viewed in the up-down direction.

[0085] 24, the second piezoelectric film 111 has a sheet shape. Therefore, the second piezoelectric film 111 has a second piezoelectric film upper principal surface US111 and a second piezoelectric film lower principal surface LS111 aligned in the vertical direction. The second piezoelectric film upper principal surface US111 is located above the second piezoelectric film lower principal surface LS111.

[0086] 24, the second piezoelectric film 111 has a rectangular shape with long sides extending in the left-right direction and short sides extending in the front-rear direction when viewed in the up-down direction. Note that the second piezoelectric film 111 has the same structure as the first piezoelectric film 31, and therefore a description thereof will be omitted.

[0087] The second upper electrode 112 is a ground electrode. The second upper electrode 112 has upper and lower principal surfaces aligned in the vertical direction. The second upper electrode 112 is electrically connected to the ground potential. As shown in FIG. 24 , the second upper electrode 112 is provided on the second piezoelectric film upper principal surface US111 of the second piezoelectric film 111. Note that the second upper electrode 112 has the same structure as the first upper electrode 32, and therefore a description thereof will be omitted.

[0088] The second lower electrode 113 is a second signal electrode. The second lower electrode 113 has upper and lower main surfaces aligned in the vertical direction. A second detection signal SigD2 corresponding to the deformation of the curved section CS2 of the flexible substrate 2 is output from the second lower electrode 113. As shown in FIG. 24 , the second lower electrode 113 is provided on the second piezoelectric film lower main surface LS111 of the second piezoelectric film 111. Note that the second lower electrode 113 has the same structure as the first lower electrode 33, and therefore a description thereof will be omitted.

[0089] As shown in Figure 24, when the flexible substrate 2 is not bent, such a second sensor 11 does not overlap with the first sensor 3, the first deformation inhibiting member 4, and the second deformation inhibiting member 5 when viewed in the vertical direction.

[0090] The electronic device 100a may include a deformation detection sensor 1d, a first housing 6, and a second housing 7, as shown in FIG.

[0091] The arithmetic circuit receives the first detection signal SigD1 output by the first sensor 3 and the second detection signal SigD2 output by the second sensor 11. The arithmetic circuit calculates a second integral value IV2 by integrating the second detection signal SigD2 over time. The arithmetic circuit also calculates the bending angle θ of the flexible substrate 2 by correlating the second integral value IV2 with the bending angle θ of the flexible substrate 2. When the value of the first detection signal SigD1 becomes discontinuous, the arithmetic circuit sets the bending angle θ of the flexible substrate 2 to θa. At this time, the arithmetic circuit corrects the second integral value IV2 to a value associated with θa.

[0092] When the bending angle θ of the flexible base material 2 is changed from 0 degrees to 180 degrees at a constant angular velocity, the value of the second detection signal SigD2 becomes a constant negative value, as shown in Fig. 26. The reason why the second detection signal SigD2 is negative is the same as the reason why the first detection signal SigD1 in the comparative example is negative, and therefore will not be explained here.

[0093] For example, as shown in FIG. 26 , if noise N is superimposed on the second detection signal SigD2, an error occurs between the actual bending angle θ of the flexible substrate 2 and the detected value of the bending angle θ of the flexible substrate 2. However, when the value of the first detection signal SigD1 becomes discontinuous (time t1 in FIG. 26 ), the arithmetic circuit sets the bending angle θ of the flexible substrate 2 to θa. At this time, the arithmetic circuit corrects the second integral value IV2 to −θa. Therefore, the value of the second detection signal SigD2 in the range of θa≦θ≦180 degrees is not affected by the superimposed noise N in the range of 0 degrees≦θ<θa. In this way, with the deformation detection sensor 1d, the first detection signal SigD1 output by the first sensor 3 can be used to improve the detection accuracy of the bending angle θ of the flexible substrate 2 by the second sensor 11.

[0094] [Fourth Modification] A deformation detection sensor 1e according to a fourth modification of the present invention will be described below with reference to the drawings. Fig. 27 is an exploded perspective view of the deformation detection sensor 1e according to the fourth modification. Note that with regard to the deformation detection sensor 1e according to the fourth modification, only the differences from the deformation detection sensor 1d according to the second embodiment will be described, and the rest will be omitted.

[0095] The deformation detection sensor 1 e differs from the deformation detection sensor 1 d in that the second sensor 11 is provided on the lower main surface LS2 of the flexible substrate 2 .

[0096] As shown in FIG. 27, the second sensor 11 is provided on the substrate lower main surface LS2 of the flexible substrate 2 so that the second upper main surface US11 is in contact with the substrate lower main surface LS2 of the flexible substrate 2.

[0097] The second upper electrode 112 is a second signal electrode. A second detection signal SigD2 corresponding to the deformation of the curved section CS2 of the flexible substrate 2 is output from the second upper electrode 112. The second lower electrode 113 is a ground electrode. The second lower electrode 113 is electrically connected to the ground potential.

[0098] The deformation detection sensor 1e as described above also has the same effect as the deformation detection sensor 1d.

[0099] [Third Embodiment] A deformation detection sensor 1f according to a third embodiment of the present invention will be described below with reference to the drawings. Fig. 28 is an exploded perspective view of the deformation detection sensor 1f according to the third embodiment. Fig. 29 is a plan view of the deformation detection sensor 1f according to the third embodiment viewed from below. Note that with regard to the deformation detection sensor 1f according to the third embodiment, only the parts that are different from the deformation detection sensor 1 according to the first embodiment will be described, and the rest will be omitted.

[0100] The deformation detection sensor 1 f differs from the deformation detection sensor 1 in that it further includes a third deformation inhibiting member 12 .

[0101] As shown in Fig. 28 , the third deformation-preventing member 12 is provided on the first upper principal surface US3 of the first sensor 3. Therefore, as shown in Fig. 29 , the third deformation-preventing member 12 has a sixth region A6 that overlaps with the first piezoelectric film 31 when viewed in the up-down direction.

[0102] The first deformation inhibiting member 4, the third deformation inhibiting member 12, and the second deformation inhibiting member 5 are arranged in this order from left to right with a gap between them, as shown in Fig. 28. Therefore, the first deformation inhibiting member 4, the second deformation inhibiting member 5, and the third deformation inhibiting member 12 do not overlap with each other when viewed in the vertical direction, as shown in Fig. 29.

[0103] 29 , the third deformation inhibiting member 12 has a rectangular shape with short sides extending in the left-right direction and long sides extending in the front-rear direction when viewed in the up-down direction. The material of the third deformation inhibiting member 12 is, for example, metal, resin, ceramic, or glass. The third deformation inhibiting member 12 is harder than the first piezoelectric film 31 of the first sensor 3. For example, the Young's modulus of the third deformation inhibiting member 12 is greater than the Young's modulus of the first piezoelectric film 31 of the first sensor 3.

[0104] As shown in FIG. 29 , the first region A1, the sixth region A6, and the second region A2 are arranged in this order from left to right with a gap between them. That is, the first region A1, the sixth region A6, and the second region A2 are arranged with a gap between them in the left-right direction. Therefore, the sixth region A6 is located between the first region A1 and the second region A2 when viewed in the vertical direction when the flexible substrate 2 is not bent. Furthermore, when the flexible substrate 2 is not bent, the sixth region A6 does not contact either the first region A1 or the second region A2 when viewed in the vertical direction. Therefore, the first region A1, the second region A2, and the sixth region A6 do not overlap with each other when viewed in the vertical direction. Furthermore, the first piezoelectric film 31 has an eleventh region A11 that does not overlap with the first deformation inhibiting member 4, the second deformation inhibiting member 5, and the third deformation inhibiting member 12 when viewed in the vertical direction.

[0105] Here, the horizontal distance D16 between the first region A1 and the sixth region A6 is defined when the flexible substrate 2 is in an unbent state. As shown in FIG. 29 , the horizontal distance D16 between the first region A1 and the sixth region A6 is the shortest distance between the portions where the first region A1 and the sixth region A6 do not contact each other. In this embodiment, the right end of the first region A1 coincides with a portion of the right edge of the first deformation inhibiting member 4. The right edge of the first deformation inhibiting member 4 extends in the front-to-rear direction. Furthermore, the left end of the sixth region A6 coincides with a portion of the left edge of the third deformation inhibiting member 12. The left edge of the third deformation inhibiting member 12 extends in the front-to-rear direction. Therefore, the horizontal distance D16 between the first region A1 and the sixth region A6 is the horizontal distance between the right edge of the first deformation inhibiting member 4 and the left edge of the third deformation inhibiting member 12 when viewed in the vertical direction.

[0106] When the flexible substrate 2 is in an unbent state, the horizontal distance D26 between the second region A2 and the sixth region A6 is defined. As shown in FIG. 29 , the horizontal distance D26 between the second region A2 and the sixth region A6 is the shortest distance between the portions where the second region A2 and the sixth region A6 do not contact each other. In this embodiment, the left end of the second region A2 coincides with a portion of the left edge of the second deformation inhibiting member 5. The left edge of the second deformation inhibiting member 5 extends in the front-to-rear direction. Furthermore, the right end of the sixth region A6 coincides with a portion of the right edge of the third deformation inhibiting member 12. The right edge of the third deformation inhibiting member 12 extends in the front-to-rear direction. Therefore, the horizontal distance D26 between the second region A2 and the sixth region A6 is the horizontal distance between the left edge of the second deformation inhibiting member 5 and the right edge of the third deformation inhibiting member 12 when viewed in the vertical direction.

[0107] 29, the left-right distance D16 between the first region A1 and the sixth region A6 is different from the left-right distance D26 between the second region A2 and the sixth region A6 when the flexible substrate 2 is not bent. In this embodiment, the left-right distance D16 between the first region A1 and the sixth region A6 is shorter than the left-right distance D26 between the second region A2 and the sixth region A6.

[0108] Here, the bending angle θ of the flexible substrate 2 at which the first deformation inhibiting member 4 and the third deformation inhibiting member 12 begin to contact each other when the bending angle θ is changed from 0 degrees to 180 degrees is defined as θa1. The bending angle θ of the flexible substrate 2 at which the second deformation inhibiting member 5 and the third deformation inhibiting member 12 begin to contact each other when the bending angle θ is changed from 0 degrees to 180 degrees is defined as θa2. θa1 is smaller than θa2 because the horizontal distance D16 between the first region A1 and the sixth region A6 is shorter than the horizontal distance D26 between the second region A2 and the sixth region A6. That is, in this embodiment, the value of the first detection signal SigD1 becomes discontinuous when the bending angle θ of the flexible substrate 2 is θa1 or θa2.

[0109] When the value of the first detection signal SigD1 becomes discontinuous, the arithmetic circuit sets the bending angle θ of the flexible base material 2 to θa1 or θa2.

[0110] When the value of the first detection signal SigD1 becomes discontinuous, the arithmetic circuit, for example, compares the absolute value of the difference between the first integral IV1 and the value associated with θa1 with the absolute value of the difference between the first integral IV1 and the value associated with θa2. If the absolute value of the difference between the first integral IV1 and the value associated with θa1 is smaller than the absolute value of the difference between the first integral IV1 and the value associated with θa2, the arithmetic circuit sets the bending angle θ of the flexible substrate 2 to θa1. In this case, the arithmetic circuit corrects the first integral IV1 to the value associated with θa1. Alternatively, if the absolute value of the difference between the first integral IV1 and the value associated with θa2 is smaller than the absolute value of the difference between the first integral IV1 and the value associated with θa1, the arithmetic circuit sets the bending angle θ of the flexible substrate 2 to θa2. In this case, the arithmetic circuit corrects the first integral IV1 to the value associated with θa2.

[0111] When the value of the first detection signal SigD1 becomes discontinuous, the arithmetic circuit may use another method to set the bending angle θ of the flexible substrate 2 to θa1 or θa2. For example, the arithmetic circuit may determine whether the bending angle θ of the flexible substrate 2 should be θa1 or θa2 based on the value of the first detection signal SigD1 immediately before and / or after the value of the first detection signal SigD1 becomes discontinuous.

[0112] The deformation detection sensor 1f can detect the bending angle of the substrate with higher accuracy. More specifically, the horizontal distance D16 between the first region A1 and the sixth region A6 is different from the horizontal distance D26 between the second region A2 and the sixth region A6 when the flexible substrate 2 is not bent. As a result, the value of the first detection signal SigD1 output by the first sensor 3 becomes discontinuous when the bending angle θ of the flexible substrate 2 is θa1 or θa2. θa1 is the bending angle θ of the flexible substrate 2 at which the first deformation inhibiting member 4 and the third deformation inhibiting member 12 begin to contact each other when the bending angle θ of the flexible substrate 2 is changed from 0 degrees to 180 degrees. θa2 is the bending angle θ of the flexible substrate 2 at which the second deformation inhibiting member 5 and the third deformation inhibiting member 12 begin to contact each other when the bending angle θ of the flexible substrate 2 is changed from 0 degrees to 180 degrees. Therefore, when the value of the first detection signal SigD1 becomes discontinuous, the arithmetic circuit can set the bending angle θ of the flexible substrate 2 to θa1 or θa2. At this time, the arithmetic circuit can correct the first integral value IV1 to a value corresponding to θa1 or θa2. As a result, the deformation detection sensor 1f can prevent the value of the first detection signal SigD1 in the range of θa1≦θ≦180 degrees from being affected by the noise N superimposed in the range of 0 degrees≦θ<θa1. Furthermore, the deformation detection sensor 1f can prevent the value of the first detection signal SigD1 in the range of θa2≦θ≦180 degrees from being affected by the noise N superimposed in the range of 0 degrees≦θ<θa2. Therefore, the deformation detection sensor 1f can detect the bending angle θ of the flexible substrate 2 with higher accuracy. As a result, the deformation detection sensor 1f can detect the bending angle of the substrate with higher accuracy.

[0113] [Fifth Modification] A deformation detection sensor 1g according to a fifth modification of the present invention will be described below with reference to the drawings. Fig. 30 is an exploded perspective view of the deformation detection sensor 1g according to the fifth modification. Note that with regard to the deformation detection sensor 1g according to the fifth modification, only the differences from the deformation detection sensor 1f according to the third embodiment will be described, and the rest will be omitted.

[0114] Deformation detection sensor 1g differs from deformation detection sensor 1f in that a first deformation inhibition member 4 is provided on the first lower main surface LS3 of the first sensor 3, a second deformation inhibition member 5 is provided on the first lower main surface LS3 of the first sensor 3, and a third deformation inhibition member 12 is provided on the first lower main surface LS3 of the first sensor 3.

[0115] As shown in Figure 30, the first sensor 3 is provided on the upper main surface US2 of the flexible substrate 2 so that the first lower main surface LS3 contacts the upper main surface of the first deformation inhibition member 4, the upper main surface of the second deformation inhibition member 5, and the upper main surface of the third deformation inhibition member 12.

[0116] The deformation detection sensor 1g as described above also has the same effect as the deformation detection sensor 1f. In this way, the third deformation inhibiting member 12 may be provided on the first upper principal surface US3 or the first lower principal surface LS3 of the first sensor 3, where the first deformation inhibiting member 4 and the second deformation inhibiting member 5 are provided.

[0117] [Sixth Modification] A deformation detection sensor 1h according to a sixth modification of the present invention will be described below with reference to the drawings. Fig. 31 is a plan view of the deformation detection sensor 1h according to the sixth modification, viewed from below. Note that with regard to the deformation detection sensor 1h according to the sixth modification, only the differences from the deformation detection sensor 1f according to the third embodiment will be described, and the rest will be omitted.

[0118] The deformation detection sensor 1h differs from the deformation detection sensor 1f in that it has a seventh region A7 where the first region A1 of the first deformation inhibition member 4 and the sixth region A6 of the third deformation inhibition member 12 overlap each other, and in that it has an eighth region A8 where the second region A2 of the second deformation inhibition member 5 and the sixth region A6 of the third deformation inhibition member 12 overlap each other.

[0119] As shown in Fig. 31 , the first region A1 and the sixth region A6 overlap each other in the seventh region A7. The first region A1 and the sixth region A6 also contact each other in the seventh region A7. However, the sixth region A6 has a fourth portion P4 that does not contact the first region A1 when viewed in the vertical direction when the flexible substrate 2 is not bent. In this modification, the fourth portion P4 is located in front of the seventh region A7.

[0120] As shown in Fig. 31 , the second region A2 and the sixth region A6 overlap each other in the eighth region A8. The second region A2 and the sixth region A6 also contact each other in the eighth region A8. However, the sixth region A6 has a fifth portion P5 that does not contact the second region A2 when viewed in the vertical direction when the flexible substrate 2 is not bent. In this modification, the fifth portion P5 is located in front of the eighth region A8.

[0121] The deformation detection sensor 1h as described above also has the same effect as the deformation detection sensor 1f. In this way, the sixth region A6 only needs to have the fourth portion P4 and the fifth portion P5 that are not in contact with the first region A1 and the second region A2 when viewed in the up-down direction when the flexible base material 2 is not bent.

[0122] [Seventh Modification] A deformation detection sensor 1i according to a seventh modification of the present invention will be described below with reference to the drawings. Fig. 32 is a plan view of the deformation detection sensor 1i according to the seventh modification, viewed from below. Note that with regard to the deformation detection sensor 1i according to the seventh modification, only the differences from the deformation detection sensor 1h according to the sixth modification will be described, and the rest will be omitted.

[0123] The deformation detection sensor 1 i differs from the deformation detection sensor 1 h in that the first deformation inhibiting member 4 , the second deformation inhibiting member 5 , and the third deformation inhibiting member 12 are included in a single member 9 .

[0124] 32, the left portion of the member 9 and the central portion of the member 9 are connected in a seventh region A7. The central portion of the member 9 and the right portion of the member 9 are connected in an eighth region A8. The member 9 is flexible in the eighth region A8.

[0125] The deformation detection sensor 1i as described above also achieves the same effect as the deformation detection sensor 1h. Note that, in this modified example, the first deformation inhibiting member 4, the second deformation inhibiting member 5, and the third deformation inhibiting member 12 are all included in the single member 9, but it is sufficient if at least two of the first deformation inhibiting member 4, the second deformation inhibiting member 5, and the third deformation inhibiting member 12 are included in the single member 9.

[0126] [Fourth embodiment] A deformation detection sensor 1j according to a fourth embodiment of the present invention will be described below with reference to the drawings. Fig. 33 is an exploded perspective view of the deformation detection sensor 1j according to the fourth embodiment. Note that with regard to the deformation detection sensor 1j according to the fourth embodiment, only the differences from the deformation detection sensor 1f according to the third embodiment will be described, and the remaining differences will be omitted.

[0127] The deformation detection sensor 1j differs from the deformation detection sensor 1f in that the first sensor 3 further includes a first electrode 34, the first upper electrode 32 is a first signal electrode and the first lower electrode 33 is a ground electrode, and the first upper electrode 32 does not cover the entire upper main surface US31 of the first piezoelectric film 31.

[0128] As shown in FIG. 33, the flexible base material 2 is bent along a first bending line L1 and a second bending line L2 extending in the front-rear direction.

[0129] As shown in FIG. 33 , the first electrode 34 is provided on the first piezoelectric film upper principal surface US31 of the first piezoelectric film 31. The first electrode 34 is a third signal electrode. The first electrode 34 has upper and lower principal surfaces aligned in the vertical direction. A third detection signal SigD3 corresponding to the deformation of the curved section CS2 of the flexible substrate 2 is output from the first electrode 34. The first electrode 34 includes an adhesive layer (not shown). The adhesive layer fixes the first electrode 34 to the first piezoelectric film upper principal surface US31 of the first piezoelectric film 31. The upper principal surface of the first electrode 34 is the first upper principal surface US3 of the first sensor 3.

[0130] 33, the first upper electrode 32 and the first electrode 34 are arranged in this order from left to right with a gap between them. Therefore, the first upper electrode 32 and the first electrode 34 do not contact each other when the flexible substrate 2 is not bent. The first upper electrode 32 and the first electrode 34 are arranged so as not to contact each other even when the flexible substrate 2 is bent. In other words, the first upper electrode 32 and the first electrode 34 do not contact each other.

[0131] As shown in FIG. 33, when the flexible substrate 2 is not bent, the first upper electrode 32 overlaps with each of the first deformation-inhibiting member 4 and the third deformation-inhibiting member 12 when viewed in the up-down direction.

[0132] As shown in FIG. 33 , when the flexible substrate 2 is not bent, the first electrode 34 overlaps with each of the first deformation-inhibiting member 4 and the third deformation-inhibiting member 12 when viewed in the up-down direction.

[0133] The deformation detection sensor 1j can accurately detect the bending angle of a substrate bent at multiple bending lines. More specifically, the flexible substrate 2 is bent at each of the first bending line L1 and the second bending line L2. When the flexible substrate 2 is not bent, the first upper electrode 32 overlaps with each of the first deformation inhibiting member 4 and the third deformation inhibiting member 12 when viewed in the vertical direction. When the flexible substrate 2 is bent at the first bending line L1, the deformation detection sensor 1j can accurately detect the bending angle θ of the flexible substrate 2 based on the first detection signal SigD1 output from the first upper electrode 32. Furthermore, when the flexible substrate 2 is bent at the second bending line L2, the deformation detection sensor 1j can accurately detect the bending angle θ of the flexible substrate 2 based on the third detection signal SigD3 output from the first electrode 34. As a result, the deformation detection sensor 1j can accurately detect the bending angle of a substrate bent at multiple bending lines.

[0134] [Eighth Modification] A deformation detection sensor 1k according to an eighth modification of the present invention will be described below with reference to the drawings. Fig. 34 is an exploded perspective view of the deformation detection sensor 1k according to the eighth modification. Note that with regard to the deformation detection sensor 1k according to the eighth modification, only the differences from the deformation detection sensor 1j according to the fourth embodiment will be described, and the rest will be omitted.

[0135] Deformation detection sensor 1k differs from deformation detection sensor 1j in that the first deformation inhibition member 4 is provided on the first lower main surface LS3 of the first sensor 3, the second deformation inhibition member 5 is provided on the first lower main surface LS3 of the first sensor 3, the third deformation inhibition member 12 is provided on the first lower main surface LS3 of the first sensor 3, the first upper electrode 32 is a ground electrode and the first lower electrode 33 is a first signal electrode, the first lower electrode 33 does not cover the entire first piezoelectric film lower main surface LS31 of the first piezoelectric film 31, and the first electrode 34 is provided on the first piezoelectric film lower main surface LS31 of the first piezoelectric film 31.

[0136] The first electrode 34 includes an adhesive layer (not shown). This adhesive layer fixes the first electrode 34 to the first piezoelectric film lower main surface LS31 of the first piezoelectric film 31, as shown in Figure 34. The lower main surface of the first electrode 34 is the first lower main surface LS3 of the first sensor 3.

[0137] 34, the first lower electrode 33 and the first electrode 34 are arranged in this order from left to right with a gap therebetween. Therefore, the first lower electrode 33 and the first electrode 34 do not contact each other when the flexible substrate 2 is not bent. The first lower electrode 33 and the first electrode 34 are arranged so as not to contact each other even when the flexible substrate 2 is bent. In other words, the first lower electrode 33 and the first electrode 34 do not contact each other.

[0138] As shown in FIG. 34, when the flexible substrate 2 is not bent, the first lower electrode 33 overlaps with each of the first deformation-inhibiting member 4 and the third deformation-inhibiting member 12 as viewed in the up-down direction.

[0139] As shown in FIG. 34, when the flexible substrate 2 is not bent, the first electrode 34 overlaps with each of the first deformation-inhibiting member 4 and the third deformation-inhibiting member 12 when viewed in the up-down direction.

[0140] The deformation detection sensor 1k as described above also has the same effects as the deformation detection sensor 1j.

[0141] Other Embodiments The deformation detection sensor according to the present invention is not limited to the deformation detection sensors 1, 1a to 1k, and can be modified within the scope of the gist thereof. Furthermore, the structures of the deformation detection sensors 1, 1a to 1k may be combined in any manner. Furthermore, the electronic device according to the present invention is not limited to the electronic devices 100, 100a to 100k that include the deformation detection sensors 1, 1a to 1k, and can be modified within the scope of the gist thereof. Furthermore, the structures of the electronic devices 100, 100a to 100k may be combined in any manner.

[0142] The flexible substrate 2 does not have to have a rectangular shape when viewed in the vertical direction.

[0143] The flexible base material 2 does not necessarily have to have long sides extending in the left-right direction and short sides extending in the front-rear direction when viewed in the up-down direction.

[0144] The flexible substrate 2 is not limited to an organic EL display, as long as it has flexibility and has an upper substrate principal surface US2 and a lower substrate principal surface LS2 aligned in the vertical direction.

[0145] It should be noted that each of the first sensor 3 and the second sensor 11 does not have to have a rectangular shape when viewed in the up-down direction.

[0146] It should be noted that each of the first sensor 3 and the second sensor 11 does not necessarily have to have a long side extending in the left-right direction and a short side extending in the front-rear direction when viewed in the up-down direction.

[0147] It should be noted that each of the first piezoelectric film 31 and the second piezoelectric film 111 does not have to have a rectangular shape when viewed in the up-down direction.

[0148] It should be noted that each of the first piezoelectric film 31 and the second piezoelectric film 111 does not necessarily have to have a long side extending in the left-right direction and a short side extending in the front-rear direction when viewed in the up-down direction.

[0149] Each of the first piezoelectric film 31 and the second piezoelectric film 111 may be a film containing polylactic acid stretched in at least one axial direction.

[0150] Note that the first piezoelectric film 31 and the second piezoelectric film 111 do not necessarily have a piezoelectric constant of d14. The first piezoelectric film 31 and the second piezoelectric film 111 may have a piezoelectric constant of d31, for example. The first piezoelectric film 31 and the second piezoelectric film 111 having a piezoelectric constant of d31 may be, for example, a PVDF (polyvinylidene fluoride) film. Furthermore, the first piezoelectric film 31 and the second piezoelectric film 111 may be made of piezoelectric ceramic.

[0151] In addition, the polarity of the charge generated by each of the first piezoelectric film 31 and the second piezoelectric film 111 when the first piezoelectric film 31 and the second piezoelectric film 111 are stretched in the left-right direction of the piezoelectric film may be the same as the polarity of the charge generated by each of the first piezoelectric film 31 and the second piezoelectric film 111 when the first piezoelectric film 31 and the second piezoelectric film 111 are stretched in the front-to-back direction of the piezoelectric film.

[0152] The uniaxial stretching direction OD of each of the first piezoelectric film 31 and the second piezoelectric film 111 may form an angle of 45 degrees with respect to the first bending line L1 when viewed in the vertical direction when the flexible substrate 2 is not bent. This 45 degrees includes, for example, an angle of approximately 45 degrees ±10 degrees. Furthermore, this 45 degrees includes an angle of approximately 225 degrees ±10 degrees (approximately −135 degrees ±10 degrees).

[0153] In addition, when the flexible substrate 2 is not bent, the angle that the uniaxial stretching direction OD of each of the first piezoelectric film 31 and the second piezoelectric film 111 forms with respect to the first bending line L1 when viewed in the vertical direction is not limited to 45 degrees or -45 degrees.

[0154] The first upper electrode 32 may be a first signal electrode, and the first lower electrode 33 may be a ground electrode.

[0155] The first deformation-inhibiting member 4 does not have to have a rectangular shape when viewed in the up-down direction.

[0156] The first deformation-preventing member 4 does not have to have short sides extending in the left-right direction and long sides extending in the front-rear direction when viewed in the up-down direction.

[0157] The first deformation-inhibiting member 4 does not have to be in contact with the upper main surface US2 of the flexible substrate 2.

[0158] The second deformation-preventing member 5 does not have to have a rectangular shape when viewed in the vertical direction.

[0159] The second deformation-preventing member 5 does not have to have short sides extending in the left-right direction and long sides extending in the front-rear direction when viewed in the up-down direction.

[0160] The second deformation-inhibiting member 5 does not have to be in contact with the upper main surface US2 of the flexible substrate 2.

[0161] The first deformation inhibiting member 4 and the second deformation inhibiting member 5 do not have to be arranged with an interval in the left-right direction.

[0162] The first region A1 does not have to be located to the left of the first bending line L1 when viewed in the up-down direction.

[0163] The second region A2 does not have to be located to the right of the first bending line L1 when viewed in the up-down direction.

[0164] The first area A1 and the second area A2 do not have to be arranged side by side with an interval in the left-right direction.

[0165] The left-right distance D1 between the first region A1 and the second region A2 does not have to be shorter than the left-right length DLR31 of the first piezoelectric film 31 when the flexible substrate 2 is not bent.

[0166] The first position PO1 is any position in the left-right direction where the first area A1 exists.

[0167] The second position PO2 is any position in the left-right direction where the second area A2 exists.

[0168] In addition, the front-to-rear length DFB4 of the first deformation inhibition member 4 at the first position PO1 does not have to be longer than the front-to-rear length DFB311 of the first piezoelectric film 31 at the first position PO1 when the flexible substrate 2 is not bent.

[0169] In addition, the front-to-rear length DFB5 of the second deformation inhibiting member 5 at the second position PO2 does not have to be longer than the front-to-rear length DFB312 of the first piezoelectric film 31 at the second position PO2 when the flexible substrate 2 is not bent.

[0170] The arithmetic circuit is not an essential component.

[0171] It should be noted that the electronic devices 100, 100a to 100k are not limited to foldable smartphones.

[0172] The first housing 6 is not limited to a box, and the first housing 6 does not have to have a rectangular parallelepiped shape.

[0173] The second housing 7 is not limited to a box, and may have a shape other than a rectangular parallelepiped.

[0174] In the deformation detection sensor 1b, the third portion P3 is not limited to being located in front of the fifth area A5.

[0175] In the deformation detection sensor 1c, the left portion of the member 8 and the right portion of the member 8 may be connected in a region that does not overlap with the first piezoelectric film 31 when viewed in the up-down direction.

[0176] In the deformation detection sensor 1d, the second upper electrode 112 may be a second signal electrode, and the second lower electrode 113 may be a ground electrode.

[0177] In the deformation detection sensor 1e, the second upper electrode 112 may be a ground electrode, and the second lower electrode 113 may be a second signal electrode.

[0178] In the deformation detection sensor 1f, the third deformation inhibiting member 12 does not have to have a rectangular shape when viewed in the vertical direction.

[0179] In the deformation detection sensor 1f, the third deformation inhibiting member 12 does not have to have short sides extending in the left-right direction and long sides extending in the front-rear direction when viewed in the up-down direction.

[0180] In the deformation detection sensor 1f, the third deformation inhibiting member 12 may be in contact with the substrate upper main surface US2 of the flexible substrate 2, or may not be in contact with the substrate upper main surface US2 of the flexible substrate 2.

[0181] In the deformation detection sensor 1f, the first deformation inhibiting member 4, the third deformation inhibiting member 12, and the second deformation inhibiting member 5 do not have to be arranged in this order from left to right with a gap therebetween.

[0182] In the deformation detection sensor 1f, the first area A1, the sixth area A6, and the second area A2 do not have to be arranged in this order from left to right with an interval between them.

[0183] In the deformation detection sensor 1f, the left-right distance D16 between the first region A1 and the sixth region A6 may be longer than the left-right distance D26 between the second region A2 and the sixth region A6. In this case, θa1 becomes larger than θa2 because the left-right distance D16 between the first region A1 and the sixth region A6 is longer than the left-right distance D26 between the second region A2 and the sixth region A6. In this case, the bending angle of the substrate can be detected with higher accuracy.

[0184] In the deformation detection sensor 1h, the fourth portion P4 is not limited to being located in front of the seventh region A7.

[0185] In the deformation detection sensor 1h, the fifth portion P5 is not limited to being located in front of the eighth region A8.

[0186] In the deformation detection sensor 1i, the left portion of the member 9 and the central portion of the member 9 may be connected in a region that does not overlap with the first piezoelectric film 31 when viewed in the up-down direction. In the deformation detection sensor 1i, the central portion of the member 9 and the right portion of the member 9 may be connected in a region that does not overlap with the first piezoelectric film 31.

[0187] In the deformation detection sensor 1j, the first upper electrode 32 and the first electrode 34 may be arranged in this order from right to left with a gap therebetween.

[0188] In the deformation detection sensor 1k, the first lower electrode 33 and the first electrode 34 may be arranged in this order from right to left with a gap therebetween.

[0189] In the deformation detection sensors 1j and 1k, the first bending angle θ1 and the second bending angle θ2 of the flexible substrate 2 may be defined as follows. That is, the first bending angle θ1 of the flexible substrate 2 may be defined as the angle formed between the first portion P1 of the flexible substrate 2 and the second portion P2 of the flexible substrate 2 when viewed in the direction in which the first bending line L1 extends. The second bending angle θ2 of the flexible substrate 2 may be defined as the angle formed between the first portion P1 of the flexible substrate 2 and the second portion P2 of the flexible substrate 2 when viewed in the direction in which the second bending line L2 extends. In this case, the deformation detection sensor 1k can accurately detect the first bending angle θ1 of the flexible substrate 2 based on the first detection signal SigD1 output from the first upper electrode 32 or the first lower electrode 33. Furthermore, the second bending angle θ2 of the flexible substrate 2 can accurately be detected based on the third detection signal SigD3 output from the first electrode 34.

[0190] The present invention has the following structure:

[0191] (1) A flexible substrate having an upper main surface and a lower main surface aligned in the vertical direction and a curved section that curves when bent at a bending line; a first sensor that outputs a first detection signal according to deformation of the curved section, the first sensor being provided on the upper main surface of the substrate and having a first upper main surface and a first lower main surface aligned in the vertical direction; a first deformation inhibiting member; and a second deformation inhibiting member, wherein the first sensor includes: a first piezoelectric film having a first upper main surface and a first lower main surface aligned in the vertical direction; a first upper electrode provided on the upper main surface of the first piezoelectric film; and a first lower electrode provided on the lower main surface of the first piezoelectric film, wherein the first deformation inhibiting member is provided on the first upper main surface or the first lower main surface, and the first deformation inhibiting member has a first region that overlaps with the first piezoelectric film when viewed in the vertical direction, a second deformation inhibiting member provided on the first upper principal surface or the first lower principal surface on which the first deformation inhibiting member is provided, the second deformation inhibiting member having a second region that overlaps with the first piezoelectric film when viewed in the vertical direction, and the first region and the second region having portions that do not contact each other when viewed in the vertical direction when the flexible base material is not bent.

[0192] (2) The deformation detection sensor described in (1), wherein the first deformation inhibiting member has a third region that is in contact with the upper main surface of the substrate and does not overlap with the first piezoelectric film when viewed in the vertical direction, and the second deformation inhibiting member has a fourth region that is in contact with the upper main surface of the substrate and does not overlap with the first piezoelectric film when viewed in the vertical direction.

[0193] (3) The deformation detection sensor according to (1) or (2), wherein the first deformation inhibiting member is provided on the first upper main surface, and the second deformation inhibiting member is provided on the first upper main surface.

[0194] (4) The deformation detection sensor according to any one of (1) to (3), wherein the first region and the second region are arranged at a distance in the left-right direction, and the left-right distance between the first region and the second region is shorter than the left-right length of the first piezoelectric film when the flexible substrate is not bent.

[0195] (5) A deformation detection sensor according to any one of (1) to (4), wherein a first position is defined as a left-right position where the first region exists, a second position is defined as a left-right position where the second region exists, a first position exists where the front-to-rear length of the first deformation-inhibiting member at the first position is longer than the front-to-rear length of the first piezoelectric film at the first position when the flexible base material is not bent, and a second position exists where the maximum value of the front-to-rear length of the second deformation-inhibiting member at the second position is longer than the front-to-rear length of the first piezoelectric film at the second position when the flexible base material is not bent.

[0196] (6) The deformation detection sensor according to any one of (1) to (5), further comprising a third deformation inhibiting member, wherein the third deformation inhibiting member is provided on the first upper main surface or the first lower main surface on which the first deformation inhibiting member and the second deformation inhibiting member are provided, and the third deformation inhibiting member has a fifth region overlapping the first piezoelectric film when viewed in the vertical direction, and the fifth region is located between the first region and the second region when viewed in the vertical direction when the flexible substrate is not bent, and the fifth region has a portion that is not in contact with either the first region or the second region when viewed in the vertical direction when the flexible substrate is not bent.

[0197] (7) The deformation detection sensor according to (6), wherein the first region, the fifth region, and the second region are arranged at intervals in the left-right direction, and the left-right distance between the first region and the fifth region is different from the left-right distance between the second region and the fifth region when the flexible substrate is not bent.

[0198] (8) The deformation detection sensor according to (6) or (7), wherein the third deformation inhibiting member is harder than the first piezoelectric film.

[0199] (9) The deformation detection sensor according to any one of (6) to (8), wherein the first sensor further includes a first electrode provided on an upper main surface of the first piezoelectric film, wherein the first upper electrode overlaps with each of the first deformation inhibiting member and the third deformation inhibiting member when viewed in the vertical direction when the flexible substrate is not bent, and the first electrode overlaps with each of the second deformation inhibiting member and the third deformation inhibiting member when viewed in the vertical direction when the flexible substrate is not bent, and the first electrode and the first upper electrode do not contact each other.

[0200] (10) The deformation detection sensor according to any one of (6) to (8), wherein the first sensor further includes a first electrode provided on a lower main surface of the first piezoelectric film, wherein the first lower electrode overlaps with each of the first deformation inhibiting member and the third deformation inhibiting member when viewed in the vertical direction when the flexible substrate is not bent, and the first electrode overlaps with each of the second deformation inhibiting member and the third deformation inhibiting member when viewed in the vertical direction when the flexible substrate is not bent, and the first electrode and the first lower electrode do not contact each other.

[0201] (11) The deformation detection sensor according to any one of (1) to (10), wherein the first upper electrode is a ground electrode electrically connected to a ground potential.

[0202] (12) The deformation detection sensor according to any one of (1) to (11), wherein the first piezoelectric film has a piezoelectric constant of d14.

[0203] (13) The deformation detection sensor according to any one of (1) to (12), wherein the first piezoelectric film is a film having polylactic acid stretched in at least one axial direction, and the uniaxial stretching direction of the first piezoelectric film forms an angle of 45 degrees or −45 degrees with respect to the bending line when viewed in the up-down direction when the flexible substrate is not bent.

[0204] (14) The deformation detection sensor according to any one of (1) to (13), wherein the first deformation inhibiting member is harder than the first piezoelectric film, and the second deformation inhibiting member is harder than the first piezoelectric film.

[0205] (15) The deformation detection sensor according to any one of (1) to (14), further comprising: a second sensor that outputs a second detection signal corresponding to deformation of the curved section, the second sensor being provided on the upper main surface or the lower main surface of the substrate and having a second upper main surface and a second lower main surface aligned in the vertical direction, wherein the second sensor includes: a second piezoelectric film having a second piezoelectric film upper main surface and a second piezoelectric film lower main surface aligned in the vertical direction; a second upper electrode provided on the upper main surface of the second piezoelectric film; and a second lower electrode provided on the lower main surface of the second piezoelectric film, wherein the second sensor does not overlap with the first sensor, the first deformation inhibiting member, and the second deformation inhibiting member when viewed in the vertical direction when the flexible substrate is not bent.

[0206] (16) The deformation detection sensor according to any one of (1) to (15), wherein the first deformation inhibiting member and the second deformation inhibiting member are included in a single member.

[0207] (17) The deformation detection sensor according to any one of (6) to (10), wherein at least two of the first deformation inhibiting member, the second deformation inhibiting member, and the third deformation inhibiting member are included in a single member.

[0208] (18) An electronic device comprising the deformation detection sensor according to any one of (1) to (17).

[0209] DESCRIPTION OF SYMBOLS 1, 10, 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k: deformation detection sensor 2: flexible substrate 3: first sensor 4: first deformation inhibiting member 5: second deformation inhibiting member 6: first housing 7: second housing 8, 9: member 11: second sensor 12: third deformation inhibiting member 31: first piezoelectric film 32: first upper electrode 33: first lower electrode 34: first electrode 100, 100a, 100b, 100c, 100d, 100e, 100f, 100g, 100h, 100i, 100j, 100k: electronic device 111: second piezoelectric film 112: second upper electrode 113: second lower electrode A1: first region A2: second region A3: third region A4: Fourth region A5: Fifth region A6: Sixth region A7: Seventh region A8: Eighth region CS2: Curved section D1, D16, D26: Distance IV1: First integral value IV2: Second integral value L1: First bending line L2: Second bending line LS11: Second lower main surface LS111: Lower main surface of second piezoelectric film LS2: Lower main surface of substrate LS3: First lower main surface LS31: Lower main surface of first piezoelectric film N: Noise NCS1, NCS3: Non-curved section OD: Uniaxial stretching direction P1: First part P2: Second part P3: Third part P4: Fourth part P5: Fifth part PO1: First position PO2: Second position SigD1: First detection signal SigD2: Second detection signal SigD3: Third detection signal US11: Second upper principal surface US111: Second piezoelectric film upper principal surface US2: Substrate upper principal surface US3: First upper principal surface US31: First piezoelectric film upper principal surface θ: Bending angle

Claims

1. A flexible substrate having an upper main surface and a lower main surface aligned in the vertical direction and a curved section that curves when bent at a bending line; a first sensor that outputs a first detection signal corresponding to a deformation of the curved section, is provided on the upper main surface of the base material, and has a first upper main surface and a first lower main surface aligned in the vertical direction; A first deformation inhibiting member; A second deformation inhibiting member; It is equipped with The first sensor is a first piezoelectric film having a first piezoelectric film upper principal surface and a first piezoelectric film lower principal surface aligned in the vertical direction; a first upper electrode provided on an upper main surface of the first piezoelectric film; a first lower electrode provided on a lower main surface of the first piezoelectric film; Contains The first deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface, The first deformation inhibiting member is a first region overlapping the first piezoelectric film when viewed in the up-down direction; a third region that is in contact with the upper main surface of the base material and does not overlap with the first piezoelectric film when viewed in the up-down direction; having the second deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface on which the first deformation inhibiting member is provided, The second deformation inhibiting member is a second region overlapping the first piezoelectric film when viewed in the up-down direction; the second deformation inhibiting member has a fourth region that is in contact with the upper main surface of the base material and does not overlap with the first piezoelectric film when viewed in the up-down direction; having The first region and the second region have portions that are not in contact with each other when viewed in the up-down direction when the flexible base material is not bent. Deformation detection sensor.

2. The first deformation inhibiting member is provided on the first upper main surface, The second deformation inhibiting member is provided on the first upper main surface. The deformation detection sensor according to claim 1 .

3. The first region and the second region are arranged at an interval in the left-right direction, a distance in the left-right direction between the first region and the second region is shorter than a length in the left-right direction of the first piezoelectric film when the flexible base material is not bent; The deformation detection sensor according to claim 1 or 2.

4. A position in the left-right direction where the first region exists is defined as a first position; A position in the left-right direction where the second region exists is defined as a second position; a first position exists where a length of the first deformation inhibiting member in a front-to-rear direction at the first position is longer than a length of the first piezoelectric film in the front-to-rear direction at the first position when the flexible base material is not bent; a second position exists where a length of the second deformation inhibiting member in the front-rear direction at the second position is longer than a length of the first piezoelectric film in the front-rear direction at the second position when the flexible base material is not bent; The deformation detection sensor according to claim 1 or 2.

5. A third deformation inhibiting member, In addition, the third deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface on which the first deformation inhibiting member and the second deformation inhibiting member are provided, the third deformation inhibiting member has a fifth region overlapping with the first piezoelectric film when viewed in the up-down direction, the fifth region is located between the first region and the second region when viewed in the up-down direction in a state in which the flexible base material is not bent, the fifth region has a portion that is not in contact with either the first region or the second region when viewed in the up-down direction in a state in which the flexible base material is not bent; The deformation detection sensor according to claim 1 or 2.

6. The first region, the fifth region, and the second region are arranged at intervals in the left-right direction, a distance in the left-right direction between the first region and the fifth region is different from a distance in the left-right direction between the second region and the fifth region when the flexible base material is not bent; The deformation detection sensor according to claim 5 .

7. the third deformation inhibiting member is harder than the first piezoelectric film; The deformation detection sensor according to claim 5 .

8. The first sensor includes a first electrode provided on an upper main surface of the first piezoelectric film, It also includes: the first upper electrode overlaps with each of the first deformation inhibiting member and the third deformation inhibiting member when viewed in the up-down direction in a state in which the flexible base material is not bent; When viewed in the up-down direction, the first electrode overlaps with each of the second deformation inhibiting member and the third deformation inhibiting member in a state in which the flexible base material is not bent; The first electrode and the first upper electrode are not in contact with each other. The deformation detection sensor according to claim 5 .

9. The first sensor includes a first electrode provided on a lower main surface of the first piezoelectric film, It also includes: the first lower electrode overlaps with each of the first deformation inhibiting member and the third deformation inhibiting member when viewed in the up-down direction in a state in which the flexible base material is not bent; When viewed in the up-down direction, the first electrode overlaps with each of the second deformation inhibiting member and the third deformation inhibiting member in a state in which the flexible base material is not bent; the first electrode and the first lower electrode are not in contact with each other; The deformation detection sensor according to claim 5 .

10. the first piezoelectric film is a film having polylactic acid stretched in at least one axial direction, The uniaxial stretching direction of the first piezoelectric film forms an angle of 45 degrees or -45 degrees with respect to the bending line when viewed in the up-down direction in a state in which the flexible base material is not bent. The deformation detection sensor according to claim 1 or 2.

11. the first deformation inhibiting member is harder than the first piezoelectric film; the second deformation inhibiting member is harder than the first piezoelectric film; The deformation detection sensor according to claim 1 or 2.

12. A second sensor that outputs a second detection signal corresponding to the deformation of the curved section, the second sensor being provided on the upper main surface of the substrate or the lower main surface of the substrate and having a second upper main surface and a second lower main surface aligned in the vertical direction; In addition, The second sensor is a second piezoelectric film having a second piezoelectric film upper principal surface and a second piezoelectric film lower principal surface aligned in the vertical direction; a second upper electrode provided on an upper main surface of the second piezoelectric film; a second lower electrode provided on a lower main surface of the second piezoelectric film; Contains When the flexible base material is not bent, the second sensor does not overlap with the first sensor, the first deformation inhibiting member, and the second deformation inhibiting member when viewed in the up-down direction. The deformation detection sensor according to claim 1 or 2.

13. The first deformation inhibiting member and the second deformation inhibiting member are included in a single member. The deformation detection sensor according to claim 1 or 2.

14. At least two of the first deformation inhibiting member, the second deformation inhibiting member, and the third deformation inhibiting member are included in a single member. The deformation detection sensor according to claim 5 .

15. A flexible substrate having an upper main surface and a lower main surface aligned in the vertical direction, and a curved section that curves when bent at a bending line; a first sensor that outputs a first detection signal corresponding to a deformation of the curved section, is provided on the upper main surface of the base material, and has a first upper main surface and a first lower main surface aligned in the vertical direction; A first deformation inhibiting member; A second deformation inhibiting member; Equipped with The first sensor is a first piezoelectric film having a first piezoelectric film upper principal surface and a first piezoelectric film lower principal surface aligned in the vertical direction; a first upper electrode provided on an upper main surface of the first piezoelectric film; a first lower electrode provided on a lower main surface of the first piezoelectric film; Contains The first deformation inhibiting member is provided on the first upper main surface, the first deformation inhibiting member has a first region overlapping with the first piezoelectric film when viewed in the up-down direction, The second deformation inhibiting member is provided on the first upper main surface, the second deformation inhibiting member has a second region overlapping with the first piezoelectric film when viewed in the up-down direction, The first region and the second region have portions that are not in contact with each other when viewed in the up-down direction when the flexible base material is not bent. Deformation detection sensor.

16. A flexible substrate having an upper main surface and a lower main surface aligned in the vertical direction, and a curved section that curves when bent at a bending line; a first sensor that outputs a first detection signal corresponding to a deformation of the curved section, is provided on the upper main surface of the base material, and has a first upper main surface and a first lower main surface aligned in the vertical direction; A first deformation inhibiting member; A second deformation inhibiting member; Equipped with The first sensor is a first piezoelectric film having a first piezoelectric film upper principal surface and a first piezoelectric film lower principal surface aligned in the vertical direction; a first upper electrode provided on an upper main surface of the first piezoelectric film; a first lower electrode provided on a lower main surface of the first piezoelectric film; Contains The first deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface, the first deformation inhibiting member has a first region overlapping with the first piezoelectric film when viewed in the up-down direction, the second deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface on which the first deformation inhibiting member is provided, the second deformation inhibiting member has a second region overlapping with the first piezoelectric film when viewed in the up-down direction, the first region and the second region have portions that are not in contact with each other when viewed in the up-down direction when the flexible base material is not bent, The first region and the second region are arranged at an interval in the left-right direction, a distance in the left-right direction between the first region and the second region is shorter than a length in the left-right direction of the first piezoelectric film when the flexible base material is not bent; Deformation detection sensor.

17. A flexible substrate having an upper main surface and a lower main surface aligned in the vertical direction, and a curved section that curves when bent at a bending line; a first sensor that outputs a first detection signal corresponding to a deformation of the curved section, is provided on the upper main surface of the base material, and has a first upper main surface and a first lower main surface aligned in the vertical direction; A first deformation inhibiting member; A second deformation inhibiting member; It is equipped with The first sensor is a first piezoelectric film having a first piezoelectric film upper principal surface and a first piezoelectric film lower principal surface aligned in the vertical direction; a first upper electrode provided on an upper main surface of the first piezoelectric film; a first lower electrode provided on a lower main surface of the first piezoelectric film; Contains The first deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface, the first deformation inhibiting member has a first region overlapping with the first piezoelectric film when viewed in the up-down direction, the second deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface on which the first deformation inhibiting member is provided, the second deformation inhibiting member has a second region overlapping with the first piezoelectric film when viewed in the up-down direction, the first region and the second region have portions that are not in contact with each other when viewed in the up-down direction when the flexible base material is not bent, A position in the left-right direction where the first region exists is defined as a first position; A position in the left-right direction where the second region exists is defined as a second position; a first position exists where a length of the first deformation inhibiting member in a front-to-rear direction at the first position is longer than a length of the first piezoelectric film in the front-to-rear direction at the first position when the flexible base material is not bent; a second position exists where a length of the second deformation inhibiting member in the front-rear direction at the second position is longer than a length of the first piezoelectric film in the front-rear direction at the second position when the flexible base material is not bent; Deformation detection sensor.

18. A flexible substrate having an upper main surface and a lower main surface aligned in the vertical direction, and a curved section that curves when bent at a bending line; a first sensor that outputs a first detection signal corresponding to a deformation of the curved section, is provided on the upper main surface of the base material, and has a first upper main surface and a first lower main surface aligned in the vertical direction; A first deformation inhibiting member; A second deformation inhibiting member; A third deformation inhibiting member; Equipped with The first sensor is a first piezoelectric film having a first piezoelectric film upper principal surface and a first piezoelectric film lower principal surface aligned in the vertical direction; a first upper electrode provided on an upper main surface of the first piezoelectric film; a first lower electrode provided on a lower main surface of the first piezoelectric film; Contains The first deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface, the first deformation inhibiting member has a first region overlapping with the first piezoelectric film when viewed in the up-down direction, the second deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface on which the first deformation inhibiting member is provided, the second deformation inhibiting member has a second region overlapping with the first piezoelectric film when viewed in the up-down direction, the first region and the second region have portions that are not in contact with each other when viewed in the up-down direction when the flexible base material is not bent, the third deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface on which the first deformation inhibiting member and the second deformation inhibiting member are provided, the third deformation inhibiting member has a fifth region overlapping with the first piezoelectric film when viewed in the up-down direction, the fifth region is located between the first region and the second region when viewed in the up-down direction in a state in which the flexible base material is not bent, the fifth region has a portion that is not in contact with either the first region or the second region when viewed in the up-down direction in a state in which the flexible base material is not bent; Deformation detection sensor.

19. A flexible substrate having an upper main surface and a lower main surface aligned in the vertical direction, and a curved section that curves when bent at a bending line; a first sensor that outputs a first detection signal corresponding to a deformation of the curved section, is provided on the upper main surface of the base material, and has a first upper main surface and a first lower main surface aligned in the vertical direction; a second sensor that outputs a second detection signal corresponding to the deformation of the curved section, the second sensor being provided on the upper main surface or the lower main surface of the substrate and having a second upper main surface and a second lower main surface aligned in the vertical direction; A first deformation inhibiting member; A second deformation inhibiting member; It is equipped with The first sensor is a first piezoelectric film having a first piezoelectric film upper principal surface and a first piezoelectric film lower principal surface aligned in the vertical direction; a first upper electrode provided on an upper main surface of the first piezoelectric film; a first lower electrode provided on a lower main surface of the first piezoelectric film; Contains The first deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface, the first deformation inhibiting member has a first region overlapping with the first piezoelectric film when viewed in the up-down direction, the second deformation inhibiting member is provided on the first upper principal surface or the first lower principal surface on which the first deformation inhibiting member is provided, the second deformation inhibiting member has a second region overlapping with the first piezoelectric film when viewed in the up-down direction, the first region and the second region have portions that are not in contact with each other when viewed in the up-down direction when the flexible base material is not bent, The second sensor is a second piezoelectric film having a second piezoelectric film upper principal surface and a second piezoelectric film lower principal surface aligned in the vertical direction; a second upper electrode provided on an upper main surface of the second piezoelectric film; a second lower electrode provided on a lower main surface of the second piezoelectric film; Contains When the flexible base material is not bent, the second sensor does not overlap with the first sensor, the first deformation inhibiting member, and the second deformation inhibiting member when viewed in the up-down direction. Deformation detection sensor.

20. A deformation detection sensor according to any one of claims 1 to 19, electronic equipment.