Sensor and electronic device

Abstract

The sensor includes: a holding plate; a piezoelectric film disposed on the holding plate and having four sides and four corners; and a reinforcing portion that suppresses deformation of the piezoelectric film, the reinforcing portion overlapping, in plan view, a first corner portion and a second corner portion among the four corner portions disposed on a diagonal line, and not overlapping a third corner portion among the four corner portions other than the first corner portion and the second corner portion.

Description

Technical Field

[0001] The present invention relates to a sensor for detecting deformation of a component and an electronic device equipped with the sensor. Background Technology

[0002] Patent Document 1 describes a displacement sensor comprising an elastomer and a piezoelectric element. The elastomer is formed of a high-strength polymer. The piezoelectric element is mounted on the elastomer. The displacement sensor is disposed in a housing. The displacement sensor detects the displacement of the housing. Specifically, the elastomer is mounted on the housing. As the housing deforms, the piezoelectric element mounted on the elastomer deforms. The piezoelectric element is polarized according to the amount of displacement of the piezoelectric element.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: International Publication No. 2012 / 137897 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] The polarization direction of a piezoelectric element varies depending on the direction of its deformation. Therefore, when using a piezoelectric element in a sensor, different polarities may occur within the element depending on the deformation. In this case, the level of the sensor's output signal varies significantly depending on the location of the deformation of the object being detected, potentially reducing the sensor's stability.

[0008] The purpose of this invention is to provide a sensor that improves the stability of the output signal.

[0009] Solution for solving the problem

[0010] A sensor according to one embodiment of the present invention includes:

[0011] Holder plate;

[0012] A piezoelectric thin film disposed on the retaining plate, having four sides and four corners; and

[0013] The reinforcing part inhibits the deformation of the piezoelectric film.

[0014] When viewed from above, the reinforcing part overlaps with the first and second corners located diagonally among the four corners, and does not overlap with the third corner other than the first and second corners among the four corners.

[0015] A sensor according to one embodiment of the present invention includes:

[0016] Holder plate;

[0017] A piezoelectric thin film disposed on the retaining plate, having four sides and four vertices; and

[0018] The reinforcing part inhibits the deformation of the piezoelectric film.

[0019] The reinforcing part, when viewed from above, is positioned near the first and second vertices on the diagonal among the four vertices, and does not overlap with the four vertices.

[0020] The effects of the invention

[0021] According to one embodiment of the present invention, a sensor is provided that improves the stability of the output signal. Attached Figure Description

[0022] Figure 1 This is an exploded perspective view of sensor 1 according to the first embodiment.

[0023] Figure 2 This is a top view of sensor 1.

[0024] Figure 3 This is an enlarged view of the piezoelectric thin film sensor 11 and the reinforcing parts 13 and 14.

[0025] Figure 4 This is a side view of the piezoelectric thin film sensor 11.

[0026] Figure 5 (A) and Figure 5 (B) are diagrams showing the deformation of the piezoelectric thin film sensor 11C1 of Comparative Example 1.

[0027] Figure 6 This is a diagram showing the deformation of the piezoelectric thin film sensor 11.

[0028] Figure 7 (A) Figure 7 (B) and Figure 7 (C) are diagrams representing sensors 1a, 1b, and 1c of Modified Example 1, respectively.

[0029] Figure 8 (A) Figure 8 (B) Figure 8 (C) Figure 8 (D) and Figure 8 (E) are diagrams representing sensors 1d, 1e, 1f, 1g, and 1h in Modified Example 2.

[0030] Figure 9 This is a top view of sensor 1i in variant example 3.

[0031] Figure 10 This is a diagram representing the sensor CP of Comparative Example 2.

[0032] Figure 11 This is a diagram representing sensor 1k in variation example 4.

[0033] Figure 12 This is a diagram showing the sensor 1m in variation example 5.

[0034] Figure 13 This is an exploded perspective view of an electronic device EE1 equipped with sensor 1.

[0035] Figure 14 This is an exploded perspective view of electronic device EE2, which is a variation of electronic device EE1. Detailed Implementation

[0036] [First Embodiment]

[0037] Hereinafter, the sensor 1 of the first embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 This is an exploded perspective view of sensor 1 according to the first embodiment. Figure 2 This is a top view of sensor 1. Figure 3 This is an enlarged view of the piezoelectric thin film sensor 11 and the reinforcing parts 13 and 14. Figure 4 This is a side view of the piezoelectric thin film sensor 11.

[0038] In this embodiment, such as Figure 1 and Figure 3 Define the direction as shown. Figure 1 As shown, the direction in which the holding plate 10 and the piezoelectric thin film sensor 11 are arranged in the order of holding plate 10 and piezoelectric thin film sensor 11 is the positive direction of the Z-axis. The opposite direction of the positive Z-axis is the negative Z-axis. Figure 3 As shown, the direction of corner 1 D11 and corner 3 D13 arranged in the order of corner 1 D11, corner 3 D13 is the positive direction of the X-axis. The opposite direction of the positive X-axis is the negative direction of the X-axis. The X-axis direction is orthogonal to the Z-axis direction. The direction of corner 4 D14 and corner 1 D11 arranged in the order of corner 4 D14, corner 1 D11 is the positive direction of the Y-axis. The opposite direction of the positive Y-axis is the negative direction of the Y-axis. The Y-axis direction is orthogonal to both the X-axis and Z-axis directions. The direction from corner 1 D11 towards corner 2 D12 is direction 1 DIR1. The direction from corner 2 D12 towards corner 1 D11 is direction 2 DIR2. The direction from corner 3 D13 towards corner 4 D14 is direction 3 DIR3. The direction from corner 4 D14 towards corner 3 D13 is direction 4 DIR4.

[0039] Furthermore, the X-axis, Y-axis, and Z-axis directions are defined for illustrative purposes. Therefore, the X-axis, Y-axis, and Z-axis directions used in actual application of sensor 1 do not necessarily need to be consistent with those in the various embodiments and modifications. Similarly, the first direction DIR1, the second direction DIR2, the third direction DIR3, and the fourth direction DIR4 used in actual application of sensor 1 do not necessarily need to be consistent with those in the various embodiments and modifications.

[0040] Sensor 1 is, for example, a module installed in an electronic device such as a smartphone. Figure 1 and Figure 2 As shown, sensor 1 includes a retaining plate 10, a piezoelectric thin film sensor 11, an adhesive 12, and reinforcing parts 13 and 14.

[0041] like Figure 1 and Figure 2 As shown, the retaining plate 10 has a plate shape including a long side extending along the X-axis and a short side extending along the Y-axis. The retaining plate 10 includes a first main surface DF10 and a second main surface UF10. The first main surface DF10 and the second main surface UF10 are arranged in the order of first main surface DF10, second main surface UF10 along the positive Z-axis. When viewed from above, the retaining plate 10 is a rectangular shape having four corners, including corner D1. As an example, corner D1 is the end of the retaining plate 10 in the negative X-axis direction and the end in the negative Y-axis direction (see reference). Figure 1 The retaining plate 10 is an elastic body capable of elastic deformation. The material of the retaining plate 10 is metal or resin, etc. For example, the outer edge of the retaining plate 10 and its vicinity are fixed to a frame-like housing of an electronic device, etc.

[0042] like Figures 1 to 3 As shown, the piezoelectric thin-film sensor 11 has a plate shape including a long side extending along the X-axis and a short side extending along the Y-axis. The piezoelectric thin-film sensor 11 has a first main surface SF1 and a second main surface SF2. The first main surface SF1 and the second main surface SF2 are arranged in the positive direction of the Z-axis in the order of first main surface SF1, second main surface SF2. The piezoelectric thin-film sensor 11 is disposed on a holding plate 10. Figure 1 and Figure 2 In the middle, the piezoelectric thin film sensor 11 is disposed at the corner D1 of the holding plate 10.

[0043] Furthermore, the piezoelectric thin film sensor 11 does not necessarily need to be fixed to the corner D1 of the retaining plate 10. The piezoelectric thin film sensor 11 can also be fixed to a corner other than corner D1 of the four corners of the retaining plate 10.

[0044] like Figure 1 and Figure 4 As shown, the piezoelectric thin film sensor 11 includes a piezoelectric thin film 110, a first electrode 111, a second electrode 112, and a detection circuit (not shown).

[0045] like Figure 1 and Figure 2 As shown, the piezoelectric film 110 has a sheet shape including a long side extending along the X-axis direction and a short side extending along the Y-axis direction. For example... Figure 4 As shown, the piezoelectric film 110 has a first film main surface DF11 and a second film main surface UF11. The first film main surface DF11 and the second film main surface UF11 are arranged in the order of the first film main surface DF11 and the second film main surface UF11 along the positive direction of the Z-axis.

[0046] The piezoelectric film 110 is polarized according to the amount of deformation of the piezoelectric film 110. The polarization direction of the piezoelectric film 110 when it is stretched along the first direction DIR1 or the second direction DIR2 is opposite to the polarization direction when it is stretched along the third direction DIR3 or the fourth direction DIR4. For example, the piezoelectric film 110 is a film formed of a chiral polymer. The chiral polymer is, for example, polylactic acid (PLA), especially L-type polylactic acid (PLLA). The backbone of PLLA, composed of chiral polymers, has a helical structure. The piezoelectric film 110 has a piezoelectric constant of d14. Figure 2 and Figure 3 As shown, the piezoelectric film 110 is uniaxially stretched to exhibit piezoelectricity with molecules aligned along the orientation direction OD1. The orientation direction OD1 forms an angle of 0 degrees or 180 degrees relative to the X-axis. For example, the 0-degree angle includes approximately 0 degrees ± 10 degrees, and the 180-degree angle includes approximately 180 degrees ± 10 degrees. The potential difference between the first main film surface DF11 and the second main film surface UF11 during polarization depends on the time derivative of the deformation of the piezoelectric film 110 caused by elongation or compression. Furthermore, the orientation direction OD1 does not necessarily need to form an angle of 0 degrees or 180 degrees relative to the X-axis. The orientation direction OD1 can also form an angle of 90 degrees or 270 degrees relative to the X-axis.

[0047] like Figure 3As shown, the piezoelectric film 110 has a rectangular shape including four vertices K11, K12, K13, and K14 and four edges H1, H2, H3, and H4 connecting the four vertices K11, K12, K13, and K14. Vertex K11 is located at the end of the piezoelectric film 110 in the negative direction of the X-axis and at the end in the positive direction of the Y-axis. Vertex K12 is located on the diagonal of vertex K11. Vertex K13 is located at the end of the piezoelectric film 110 in the positive direction of the X-axis and at the end in the positive direction of the Y-axis. Vertex K14 is located on the diagonal of vertex K13. Edge H1 connects vertices K11 and K13. Edge H2 connects vertices K12 and K13. Edge H3 connects vertices K12 and K14. Edge H4 connects vertices K11 and K14.

[0048] like Figure 2 and Figure 3 As shown, the piezoelectric film 110 has four corners: a first corner D11, a second corner D12, a third corner D13, and a fourth corner D14.

[0049] In this embodiment, such as Figure 3 As shown, the first corner D11 is the end of the piezoelectric film 110 in the negative X direction and the end in the positive Y direction. The first corner D11 includes vertex K11 and the vicinity of vertex K11. The first corner D11 includes the position in the piezoelectric film 110 other than vertex K11 (the vicinity of vertex K11). The first corner D11 does not include the midpoint M1 of edge H1 and the midpoint M4 of edge H4.

[0050] In this embodiment, the second corner D12 is located diagonally opposite the first corner D11. The second corner D12 includes vertex K12 and the vicinity of vertex K12. The second corner D12 includes the position in the piezoelectric film 110 other than vertex K12 (the vicinity of vertex K12). The second corner D12 does not include the midpoint M2 of edge H2 and the midpoint M3 of edge H3.

[0051] In this embodiment, such as Figure 3 As shown, the third corner D13 is the end of the piezoelectric film 110 in the positive X direction and the end in the positive Y direction. The third corner D13 includes vertex K13 and the vicinity of vertex K13. The third corner D13 includes the position in the piezoelectric film 110 other than vertex K13 (the vicinity of vertex K13). The third corner D13 does not include midpoint M1 and midpoint M2.

[0052] In this embodiment, the fourth corner D14 is located diagonally opposite the third corner D13. The fourth corner D14 includes the vertex K14 and the vicinity of the vertex K14. The fourth corner D14 includes the position in the piezoelectric film 110 other than the vertex K14 (the vicinity of the vertex K14). The fourth corner D14 does not include the midpoint M3 and the midpoint M4.

[0053] The first electrode 111 is, for example, a signal electrode. Figure 4 As shown, the first electrode 111 is disposed on the main surface of the first thin film DF11. The first electrode 111 is fixed to the main surface of the first thin film DF11 using an adhesive (not shown) such as OCA (Optically Clear Adhesive). The first electrode 111 covers approximately the entire surface of the main surface of the first thin film DF11. The first electrode 111 is connected to the holding plate 10 via adhesive 12.

[0054] The second electrode 112 is, for example, a reference electrode. The second electrode 112 is connected to a reference potential (for example, ground potential). The second electrode 112 is disposed on the second thin film main surface UF11. The second electrode 112 is fixed to the second thin film main surface UF11 using an adhesive such as OCA (not shown). The second electrode 112 covers approximately the entire surface of the second thin film main surface UF11. Through the second electrode 112 connected to the reference potential, the signal generated by the piezoelectric thin film sensor 11 will not affect external devices as noise.

[0055] Alternatively, it is not necessary for the first electrode 111 to be the signal electrode and the second electrode 112 to be the reference electrode. Alternatively, the first electrode 111 can be the reference electrode and the second electrode 112 can be the signal electrode.

[0056] The detection circuit converts the charge generated by the piezoelectric film 110 into a voltage signal. The detection circuit then generates a digital signal by performing an analog-to-digital (AD) conversion on the voltage signal.

[0057] like Figure 1 As shown, adhesive 12 is disposed between the retaining plate 10 and the piezoelectric thin film sensor 11. Adhesive 12 is, for example, double-sided tape with adhesive properties. Of course, adhesive 12 does not necessarily have to be double-sided tape.

[0058] The piezoelectric thin-film sensor 11 is fixed to the second main surface UF10 of the retaining plate 10 using adhesive 12. Thus, the piezoelectric thin-film sensor 11 outputs a signal corresponding to the deformation of the retaining plate 10. Specifically, when the user presses the retaining plate 10 along the normal direction, the retaining plate 10 bends and deforms. As the retaining plate 10 deforms, the piezoelectric thin-film sensor 11 fixed to the retaining plate 10 bends and deforms. The piezoelectric thin-film sensor 11 outputs a signal corresponding to its deformation.

[0059] like Figures 1 to 3 As shown, the reinforcing part 13 has a rectangular shape including four sides. The reinforcing part 13 is disposed on the second main surface SF2. The reinforcing part 13 is disposed at the first corner D11. Figures 1 to 3 As shown, the reinforcing portion 13 overlaps with the piezoelectric film sensor 11 when viewed from above. The reinforcing portion 13 also overlaps with the first corner portion D11 when viewed from above. The reinforcing portion 13 can be formed of a material having an elastic modulus higher than that of the retaining plate 10, or it can be formed of a material having an elastic modulus lower than that of the retaining plate 10. The reinforcing portion 13 suppresses deformation of the piezoelectric film 110. The reinforcing portion 13 also suppresses deformation of the first corner portion D11. Specifically, the first corner portion D11, by having the reinforcing portion 13, is less prone to deformation (hardening) compared to portions of the piezoelectric film 110 without the reinforcing portions 13 and 14. Therefore, even when a force in the normal direction is applied to the piezoelectric film sensor 11 (e.g., when a force is applied by the user pressing the retaining plate 10), the first corner portion D11 is less likely to twist in the first direction DIR1 or the second direction DIR2 due to this force.

[0060] like Figures 1 to 3 As shown, the reinforcing part 14 is disposed at the second corner D12. The reinforcing part 14 overlaps with the second corner D12 when viewed from above. The reinforcing part 14 suppresses deformation of the second corner D12. The other structures of the reinforcing part 14 are the same as those of the reinforcing part 13, therefore, description is omitted.

[0061] In this embodiment, the reinforcing parts 13 and 14 are not located at the third corner D13 and the fourth corner D14. The reinforcing parts 13 and 14 do not overlap with the third corner D13 and the fourth corner D14 when viewed from above.

[0062] Furthermore, the reinforcing parts 13 and 14 can also be frame-shaped housings found in electronic devices such as smartphones. For example, edge H4 and its vicinity and edge H3 and their vicinity of the piezoelectric thin film sensor 11 are fixed to the retaining plate 10 by this housing. The housing suppresses deformation of the first corner D11, the second corner D12, and the fourth corner D14.

[0063] (Effect)

[0064] The effect of sensor 1 will be explained below by comparing it with the sensor of the comparative example (hereinafter referred to as comparative example 1). Figure 5 (A) and Figure 5 (B) are diagrams showing the deformation of the piezoelectric thin film sensor 11C1 of Comparative Example 1. Figure 6 This is a diagram showing the deformation of the piezoelectric thin-film sensor 11. In Figure 6 In the experiment, the reinforcing part overlapped not only with the first corner D11 and the second corner D12, but also with the fourth corner D14. Figure 6In the experiment, the piezoelectric thin film sensor 11 was positioned at the corner D1 of the holding plate 10, but did not overlap with the frame-shaped housing or other components of the electronic device.

[0065] The piezoelectric thin film sensor 11C1 of Comparative Example 1 differs from the piezoelectric thin film sensor 11 of this embodiment in that the reinforcing portions 13 and 14 do not overlap with the first corner portion D11 and the second corner portion D12. Therefore, the piezoelectric thin film 110 of the piezoelectric thin film sensor 11C1 of Comparative Example 1 is not suppressed by the reinforcing portions 13 and 14 to prevent deformation. Figure 5 (A) indicates the deformation mode of the piezoelectric thin film sensor 11C1 when the third corner D13 is pressed along the normal direction. When the third corner D13 of the piezoelectric thin film sensor 11C1 is pressed along the normal direction, the piezoelectric thin film 110 extends along the fourth direction DIR4 and contracts along the first direction DIR1 and the second direction DIR2, so the portion that is positively polarized relative to the reference potential is dominant. Figure 5 (B) indicates the deformation mode of the piezoelectric thin film sensor 11C1 when the second corner D12 is pressed along the normal direction. When the second corner D12 of the piezoelectric thin film sensor 11C1 is pressed along the normal direction, the piezoelectric thin film 110 extends along the first direction DIR1 and contracts along the third direction DIR3 and the fourth direction DIR4, so the portion polarized negatively relative to the reference potential is dominant.

[0066] The output of the piezoelectric thin film sensor 11C1 corresponds to the sum of the charges generated in the piezoelectric thin film 110. Therefore, in the piezoelectric thin film sensor 11C1 of Comparative Example 1, the polarity of the sensor output is reversed when the second corner D12 is pressed along the normal direction and when the fourth corner D14 is pressed along the normal direction.

[0067] Furthermore, in Comparative Example 1, assuming that any one of the midpoints (midpoints M1 to M4) of the four sides is pressed, the portion polarized positively with respect to the reference potential and the portion polarized negatively with respect to the reference potential become the same area. Therefore, in the piezoelectric thin film sensor 11C1 of Comparative Example 1, when any one of the midpoints (midpoints M1 to M4) of the four sides is pressed, the output of the sensor becomes extremely small or becomes "0".

[0068] In the sensor 1 of this embodiment, since the reinforcing portions 13 and 14 do not overlap with the third corner portion D13, the piezoelectric film 110 also elongates along the fourth direction DIR4 when the third corner portion D13 is pressed along the normal direction. On the other hand, the deformation of the first corner portion D11 and the second corner portion D12 is suppressed by the reinforcing portions 13 and 14. Therefore, the piezoelectric film 110 is difficult to contract or elongate along the first direction DIR1 or the second direction DIR2. As a result, the portion of the piezoelectric film 110 that is positively polarized relative to the reference potential is dominant. Therefore, in the sensor 1 of this embodiment, the output of the piezoelectric film sensor 11 when the third corner portion D13 is pressed along the normal direction becomes... Figure 5 The output of Comparative Example 1, shown in (A), is in the same manner as that of the piezoelectric thin film sensor 11C1.

[0069] Figure 6 This describes the deformation pattern of the piezoelectric thin film sensor 11 when the second corner D12 is pressed along the normal direction. The deformation of the first corner D11 and the second corner D12 is suppressed by the reinforcing portions 13 and 14. Therefore, the piezoelectric thin film 110 is difficult to shrink or stretch along the first direction DIR1 and the second direction DIR2. On the other hand, the force of pressing the second corner D12 along the normal direction is transmitted to the holding plate 10, causing the piezoelectric thin film 110 to stretch along the fourth direction DIR4. Therefore, as a whole, the portion of the piezoelectric thin film 110 that is positively polarized relative to the reference potential is dominant. Therefore, in the piezoelectric thin film sensor 11 of this embodiment, the polarity of the sensor output does not reverse when the second corner D12 is pressed along the normal direction and when the fourth corner D14 is pressed along the normal direction.

[0070] Furthermore, in the piezoelectric thin film sensor 11 of this embodiment, regardless of which of the four sides' midpoints (midpoints M1 to M4) is pressed, the portion polarized positively relative to the reference potential is dominant. Therefore, in this embodiment, the piezoelectric thin film sensor 11 will not become extremely small or become "0" when any of the four sides' midpoints (midpoints M1 to M4) are pressed.

[0071] Therefore, sensor 1 can prevent the output signal from having an undesirable polarity, either positive or negative. Furthermore, sensor 1 can prevent a significant decrease in the value of the output signal. Thus, sensor 1 can improve the stability of the output signal of the piezoelectric thin film sensor 11.

[0072] Furthermore, the arithmetic circuit (not shown) connected to sensor 1 determines that the user has performed a pressing operation when the value of the output signal of the piezoelectric thin film sensor 11 exceeds a predetermined threshold. The arithmetic circuit (not shown) determines that the user has released the pressing operation when the value of the output signal of the piezoelectric thin film sensor 11 becomes less than a predetermined threshold (a predetermined negative value). In this embodiment, sensor 1 does not experience either a reversal of the output signal polarity or a significant decrease in the output signal value, thus preventing misjudgments by the arithmetic circuit.

[0073] Furthermore, even when the orientation direction OD1 of the piezoelectric film 110 in sensor 1 forms an angle of 0 degrees or 180 degrees with respect to the X-axis direction, the polarity of the output of sensor 1 will not reverse when the second corner D12 is pressed along the normal direction and when the fourth corner D14 is pressed along the normal direction. Therefore, the piezoelectric film sensor 11 can achieve the effect that its output as a sensor will not become extremely small or become "0".

[0074] [Variation Example 1]

[0075] Hereinafter, with reference to the accompanying drawings, sensors 1a, 1b, and 1c of the modified example 1 of sensor 1 will be described. Figure 7 (A) Figure 7 (B) and Figure 7 (C) are diagrams representing sensors 1a, 1b, and 1c of Modified Example 1, respectively.

[0076] like Figure 7 As shown in (A), sensor 1a differs from sensor 1 in that it has reinforcing parts 13a and 14a that are different from those of reinforcing parts 13 and 14. Specifically, the shapes of reinforcing parts 13a and 14a are each L-shaped when viewed from above. The other structures of sensor 1a are the same as those of sensor 1, so the description is omitted.

[0077] like Figure 7 As shown in (B), sensor 1b differs from sensor 1 in that it has reinforcing parts 13b and 14b that are different from reinforcing parts 13 and 14. Specifically, the shapes of reinforcing parts 13b and 14b are triangular when viewed from above. The other structures of sensor 1b are the same as those of sensor 1, so the description is omitted.

[0078] like Figure 7 As shown in (C), sensor 1c differs from sensor 1 in that it has a reinforcing part 13c. The reinforcing part 13c has a rectangular shape extending from the first corner D11 toward the second corner D12. The other structures of sensor 1c are the same as those of sensor 1, so descriptions are omitted.

[0079] Sensors 1a, 1b, and 1c perform the same function as sensor 1.

[0080] [Modification Example 2]

[0081] Hereinafter, with reference to the accompanying drawings, sensors 1d, 1e, 1f, 1g, and 1h of Modification 2 of Sensor 1 will be described. Figure 8 (A) Figure 8 (B) Figure 8 (C) Figure 8 (D) and Figure 8 (E) are diagrams representing sensors 1d, 1e, 1f, 1g, and 1h in Modified Example 2.

[0082] Sensors 1d, 1e, 1f, 1g, and 1h differ from sensor 1 in that the reinforcing part overlaps with the fourth corner part D14 when viewed from above.

[0083] like Figure 8 As shown in (A), the sensor 1d also includes a reinforcing part 15. The reinforcing part 15 is disposed at the fourth corner D14. The reinforcing part 15 overlaps with the fourth corner D14 when viewed from above. The other structures of the reinforcing part 15 are the same as those of the reinforcing part 13, so the description is omitted.

[0084] like Figure 8 As shown in (B), the sensor 1e includes a reinforcing portion 13e that overlaps with the first corner portion D11, the second corner portion D12, and the fourth corner portion D14 when viewed from above. The reinforcing portion 13e has an L-shape when viewed from above. A portion of the reinforcing portion 13e extends from the first corner portion D11 toward the fourth corner portion D14. Therefore, the reinforcing portion 13e is positioned in the portion connecting the fourth corner portion D14 and the first corner portion D11. The remaining portion of the reinforcing portion 13e extends from the fourth corner portion D14 toward the second corner portion D12. Therefore, the reinforcing portion 13e is positioned in the portion connecting the fourth corner portion D14 and the second corner portion D12. The other structures of the reinforcing portion 13e are the same as those of the reinforcing portion 13, and therefore descriptions are omitted.

[0085] like Figure 8 As shown in (C), sensor 1f has a reinforcing portion 13f that is different from reinforcing portion 13e. A portion of reinforcing portion 13f extends from the first corner portion D11 toward the second corner portion D12. The other structures of reinforcing portion 13f are the same as those of reinforcing portion 13e, so the description is omitted.

[0086] like Figure 8 As shown in (D), the sensor 1g includes a reinforcing part 13g. The reinforcing part 13g is triangular in shape when viewed from above. The three vertices of the reinforcing part 13g are located at the first corner D11, the second corner D12, and the fourth corner D14, respectively. The other structures of the reinforcing part 13g are the same as those of the reinforcing part 13, so the description is omitted.

[0087] like Figure 8 As shown in (E), the sensor 1h includes a reinforcing portion 13h. The reinforcing portion 13h does not cover the vertex K13 and the area around the vertex K13. The reinforcing portion 13h covers all parts of the piezoelectric thin film sensor 11 except for the vertex K13 and the area around the vertex K13. The other structures of the reinforcing portion 13h are the same as those of the reinforcing portion 13, so descriptions are omitted.

[0088] Sensors 1a to 1h each perform the same function as sensor 1.

[0089] [Modification Example 3]

[0090] Hereinafter, the sensor 1i of the modified example 3 of the sensor 1 will be described with reference to the accompanying drawings. Figure 9 This is a top view of sensor 1i in variant example 3.

[0091] like Figure 9 As shown, sensor 1i differs from sensor 1 in that it has reinforcing portions 13i, 14i, 15i, and 16i, which are different from reinforcing portions 13 and 14. Reinforcing portions 13i, 14i, 15i, and 16i are not disposed at vertices K11 to K14 on the piezoelectric thin film sensor 11. That is, reinforcing portions 13i, 14i, 15i, and 16i do not overlap with vertices K11 to K14 when viewed from above. Vertex K11 corresponds to the first vertex in this application. Vertex K12 corresponds to the second vertex in this application. Vertex K13 corresponds to the third vertex in this application. Vertex K14 corresponds to the fourth vertex in this application.

[0092] Reinforcing part 13i is positioned near vertex K11 when viewed from above. Reinforcing part 13i is located between vertex K11 and midpoint M1. Reinforcing part 13i does not overlap with vertex K11 and midpoint M1 when viewed from above. Reinforcing part 14i is positioned near vertex K11 when viewed from above. Reinforcing part 14i is located between vertex K11 and midpoint M4. Reinforcing part 14i does not overlap with vertex K11 and midpoint M4 when viewed from above. Reinforcing parts 13i and 14i suppress deformation of the first corner D11.

[0093] Reinforcing part 15i is positioned near vertex K12 when viewed from above. Reinforcing part 15i is located between vertex K12 and midpoint M2. Reinforcing part 15i does not overlap with vertex K12 and midpoint M2 when viewed from above. Reinforcing part 16i is positioned near vertex K12 when viewed from above. Reinforcing part 16i is located between vertex K12 and midpoint M3. Reinforcing part 16i does not overlap with vertex K12 and midpoint M3 when viewed from above. Reinforcing parts 15i and 16i suppress deformation of the second corner D12.

[0094] The reinforcements 13i to 16i do not suppress the deformation of the third corner D13 and the fourth corner D14.

[0095] (Effect)

[0096] Sensor 1i performs the same function as sensor 1. This function will be explained below with reference to the accompanying drawings. Figure 10 This is a diagram representing the sensor CP in Comparative Example 2. (Example:) Figure 10 As shown, the sensor CP has four reinforcing parts CP13, CP14, CP15, and CP16. The reinforcing parts CP13, CP14, CP15, and CP16 are not located at the corners of the piezoelectric film of the piezoelectric film sensor CP11 within the sensor CP. The reinforcing parts CP13, CP14, CP15, and CP16 overlap with the midpoints CPM1, CPM4, CPM2, and CPM3, respectively, when viewed from above.

[0097] In the sensor CP, the reinforcing portions CP13, CP14, CP15, and CP16 do not overlap with the four corners of the piezoelectric film. Therefore, when the piezoelectric film in the sensor CP is pressed along the normal direction at the third corner DP13 or the fourth corner DP14, it elongates along the third direction DIR3 and the fourth direction DIR4, and contracts along the first direction DIR1 and the second direction DIR2, thus the portion polarized positively relative to the reference potential is dominant. On the other hand, when the piezoelectric film in the sensor CP is pressed along the normal direction at the first corner DP11 or the second corner DP12, it elongates along the first direction DIR1 and the second direction DIR2, and contracts along the third direction DIR3 and the fourth direction DIR4, thus the portion polarized negatively relative to the reference potential is dominant.

[0098] The output of the sensor CP as a piezoelectric thin film sensor corresponds to the sum of charges generated in the piezoelectric thin film. Therefore, in the piezoelectric thin film sensor of Comparative Example 2, for example, when the second corner D12 is pressed along the normal direction and the fourth corner D14 is pressed along the normal direction, the polarity of the sensor output is reversed.

[0099] On the other hand, in sensor 1i, the reinforcing portions 13i and 14i are disposed near vertex K11, and the reinforcing portions 15i and 16i are disposed near vertex K12. Therefore, compared with sensor CP, the piezoelectric film 110 is less likely to elongate along the first direction DIR1 and the second direction DIR2. Thus, in the piezoelectric film of sensor 1i, for the same reason as sensor 1, the polarity of the sensor output will not reverse when the second corner D12 is pressed along the normal direction and when the fourth corner D14 is pressed along the normal direction. Furthermore, when any one of the midpoints (midpoints M1 to M4) of the four sides of the piezoelectric film sensor 11 of sensor 1i is pressed, the sensor output will not become extremely small or become "0". Therefore, sensor 1i, like sensor 1, can prevent the output of a signal with an undesirable polarity, either positive or negative. In addition, sensor 1i can prevent a significant decrease in the value of the output signal. Therefore, sensor 1i can improve the stability of the output signal of piezoelectric film sensor 11.

[0100] [Variation Example 4]

[0101] Hereinafter, the sensor 1k of the modified example 4 of the sensor 1 will be described with reference to the accompanying drawings. Figure 11 This is a diagram representing sensor 1k in variation example 4.

[0102] like Figure 11 As shown, sensor 1k differs from sensor 1 in that the reinforcing parts 13 and 14 do not overlap with the piezoelectric thin film sensor 11 when viewed from above. Reinforcing parts 13 and 14 are, for example, disposed on the holding plate 10. Reinforcing part 13 is disposed near the first corner D11. In sensor 1k, reinforcing part 13 is disposed next to the first corner D11. Reinforcing part 13 is located on the positive side of the Y-axis compared to the piezoelectric thin film sensor 11. Reinforcing part 13 is not in contact with the piezoelectric thin film sensor 11. Reinforcing part 14 is disposed near the second corner D12. Reinforcing part 14 is disposed next to the second corner D12. Reinforcing part 14 is located on the positive side of the X-axis compared to the piezoelectric thin film sensor 11.

[0103] Since the reinforcing part 13 is disposed near the first corner D11, the first corner D11 is fixed to the retaining plate 10. Since the reinforcing part 14 is disposed near the second corner D12, the second corner D12 is fixed to the retaining plate 10. Therefore, in the piezoelectric thin film sensor 11 of sensor 1k, similarly to sensor 1, when the second corner D12 is pressed along the normal direction and when the fourth corner D14 is pressed along the normal direction, the polarity of the sensor output will not reverse. In addition, when any of the midpoints (midpoints M1 to M4) of the four sides of the piezoelectric thin film sensor 11 of sensor 1k is pressed, the output of the sensor will not become extremely small or become "0". Therefore, for the same reasons as sensor 1, sensor 1k can improve the stability of the output signal of piezoelectric thin film sensor 11.

[0104] [Variation Example 5]

[0105] Hereinafter, the sensor 1m of the modified example 5 of the sensor 1 will be described with reference to the accompanying drawings. Figure 12 This is a diagram showing the sensor 1m in variation example 5.

[0106] like Figure 12 As shown, sensor 1m differs from sensor 1 in that multiple sets of piezoelectric film sensors and reinforcing parts are arranged on the holding plate 10. Figure 12 In this embodiment, two sets of piezoelectric thin-film sensors and reinforcing parts are arranged on the holding plate 10. Specifically, sensor 1m differs from sensor 1 in that it also includes a piezoelectric thin-film sensor 20 and reinforcing parts 23 and 24. The piezoelectric thin-film sensor 20 is disposed at corner D2 of the holding plate 10. Corner D2 is located diagonally opposite corner D1 of the holding plate 10. Reinforcing part 23 is disposed at the first corner of the piezoelectric thin-film sensor 20. Reinforcing part 24 is disposed at the second corner of the piezoelectric thin-film sensor 20. The other structures of the piezoelectric thin-film sensor 20 are the same as those of the piezoelectric thin-film sensor 11, so descriptions are omitted.

[0107] In addition, the piezoelectric thin film sensor 20 can also be disposed at a corner other than corners D1 and D2 in the corner of the holding plate 10.

[0108] In addition, the sensor 1m can also have three or more sets of piezoelectric thin film sensors and reinforcing parts.

[0109] [Electronic Equipment EE1]

[0110] The electronic device EE1 equipped with sensor 1 will be described below with reference to the accompanying drawings. Figure 13 This is an exploded perspective view of an electronic device EE1 equipped with sensor 1.

[0111] like Figure 13As shown, the electronic device EE1 includes a sensor 1 and a touch panel 30. As an example, the touch panel 30 is located between the holding plate 10 and the piezoelectric thin-film sensor 11. The size of the touch panel 30 is approximately the same as the size of the holding plate 10. In the electronic device EE1, the piezoelectric thin-film sensor 11 is disposed at a corner of the touch panel 30. The touch panel 30 is a resistive film touch panel or a capacitive touch panel, etc. Such an electronic device EE1 is a smartphone, etc.

[0112] [A variation of electronic device EE1]

[0113] Hereinafter, electronic device EE2, which is a variation of electronic device EE1, will be described with reference to the accompanying drawings. Figure 14 This is an exploded perspective view of electronic device EE2, which is a variation of electronic device EE1.

[0114] like Figure 14 As shown, electronic device EE2 differs from electronic device EE1 in that it also includes a display panel 40. For example, the display panel 40 is located between the touch panel 30 and the piezoelectric thin-film sensor 11. The size of the display panel 40 is approximately the same as the size of the holding plate 10. In electronic device EE2, the piezoelectric thin-film sensor 11 is disposed at a corner of the display panel 40. The display panel 40 is an organic EL display or a liquid crystal display, etc. Such electronic device EE2 is a smartphone, etc.

[0115] Furthermore, the display panel 40 does not necessarily have to be located between the touch panel 30 and the piezoelectric film sensor 11. For example, the display panel 40 can also be located between the touch panel 30 and the holding plate 10.

[0116] [Other Implementation Methods]

[0117] It should be considered that the description of this embodiment is illustrative in all respects and not restrictive. The scope of the invention is defined not by the above embodiments, but by the claims. Moreover, the scope of the invention includes the scope equivalent to the claims.

[0118] Furthermore, the sensors of the present invention are not limited to sensors 1, 1a to 1m, and can be modified within the scope of their essence. The structures of sensors 1, 1a to 1m can also be arbitrarily combined.

[0119] Furthermore, the first and second corner portions in this invention only need to be positioned diagonally. Therefore, the combination of the first and second corner portions does not necessarily have to be... Figures 1 to 14 The combination of the two corners shown. For example, in sensor 1, the second corner D12 may correspond to the first corner of the present invention, and the fourth corner D14 may correspond to the second corner of the present invention.

[0120] The present invention has the following structure.

[0121] (1) A sensor, wherein,

[0122] This sensor has the following features:

[0123] Holder plate;

[0124] A piezoelectric thin film disposed on the retaining plate, having four sides and four corners; and

[0125] The reinforcing part inhibits the deformation of the piezoelectric film.

[0126] When viewed from above, the reinforcing part overlaps with the first and second corners located diagonally among the four corners, and does not overlap with the third corner other than the first and second corners among the four corners. (2)

[0128] A sensor, wherein,

[0129] This sensor has the following features:

[0130] Holder plate;

[0131] A piezoelectric thin film disposed on the retaining plate, having four sides and four vertices; and

[0132] The reinforcing part inhibits the deformation of the piezoelectric film.

[0133] The reinforcing part, when viewed from above, is positioned near the first and second vertices on the diagonal among the four vertices, and does not overlap with the four vertices. (3)

[0135] According to the sensor described in (1), wherein,

[0136] The reinforcing part overlaps with the fourth corner part located on the diagonal line of the third corner part. (4)

[0138] According to the sensor described in (3), wherein,

[0139] The reinforcing portion is positioned at a location overlapping the portion of the piezoelectric film that connects the fourth corner portion to the first corner portion and the portion that connects the fourth corner portion to the second corner portion. (5)

[0141] According to the sensor described in (2), wherein,

[0142] The reinforcing part is positioned so as not to overlap with the vicinity of the third vertex (other than the first and second vertices of the four vertices), but rather to overlap with the vicinity of the fourth vertex located diagonally opposite the third vertex. (6)

[0144] According to the sensor described in (2) or (5), wherein,

[0145] The reinforcing portion does not overlap with the piezoelectric film when viewed from above. (7)

[0147] According to any one of (1) to (6), the sensor, wherein,

[0148] The piezoelectric film is disposed at the corner of the retaining plate. (8)

[0150] According to any one of (1) to (7), the sensor, wherein,

[0151] Multiple sets of the piezoelectric film and the reinforcing portion are arranged on the retaining plate. (9)

[0153] According to any one of (1) to (8), the sensor, wherein,

[0154] The sensor also includes a piezoelectric film sensor comprising the piezoelectric film, a first electrode, and a second electrode.

[0155] The piezoelectric thin film has a first main film surface and a second main film surface.

[0156] The first electrode is disposed on the main surface of the first thin film and is in contact with the holding plate.

[0157] The second electrode is disposed on the main surface of the second thin film and is connected to the reference potential. (10)

[0159] An electronic device, wherein,

[0160] This electronic device has:

[0161] The sensor described in any one of (1) to (9); and

[0162] Touch panel. (11)

[0164] According to the electronic device described in (10), wherein,

[0165] The electronic device also features a display panel.

[0166] Explanation of reference numerals in the attached figures

[0167] 1. 1a-1m, CP, sensor; 10. Holding plate; 11. 11C1, CP11, 20. Piezoelectric film sensor; 110. Piezoelectric film; 111. First electrode; 112. Second electrode; 12. Adhesive; 13. 13a-13i, 14. 14a, 14b, 14i, 15. 15i, 16i, 23. 24. CP13-CP16. Reinforcing part; 30. Touch panel; 40. Display panel; D1, D2. Corner; D11, DP11. First corner; D12, DP12. 2nd corner; D13, DP13, 3rd corner; D14, DP14, 4th corner; H1~H4, edges; M1~M4, CPM1~CPM4, midpoints; K11~K14, vertices; EE1, EE2, electronic devices; DF10, SF1, 1st principal surface; UF10, SF2, 2nd principal surface; DF11, 1st thin film principal surface; UF11, 2nd thin film principal surface; DIR1, 1st direction; DIR2, 2nd direction; DIR3, 3rd direction; DIR4, 4th direction; OD1, orientation direction.

Claims

1. A sensor, wherein, This sensor has the following features: Holder plate; A piezoelectric thin film disposed on the retaining plate, having four sides and four corners; and The reinforcing part inhibits the deformation of the piezoelectric film. When viewed from above, the reinforcing part overlaps with the first and second corners located diagonally among the four corners, and does not overlap with the third corner other than the first and second corners among the four corners.

2. A sensor, wherein, This sensor has the following features: Holder plate; A piezoelectric thin film disposed on the retaining plate, having four sides and four vertices; and The reinforcing part inhibits the deformation of the piezoelectric film. The reinforcing part, when viewed from above, is positioned near the first and second vertices on the diagonal among the four vertices, and does not overlap with the four vertices.

3. The sensor according to claim 1, wherein, The reinforcing part overlaps with the fourth corner part located on the diagonal line of the third corner part.

4. The sensor according to claim 3, wherein, The reinforcing portion is positioned at a location overlapping the portion of the piezoelectric film that connects the fourth corner portion to the first corner portion and the portion that connects the fourth corner portion to the second corner portion.

5. The sensor according to claim 2, wherein, The reinforcing part is positioned so as not to overlap with the vicinity of the third vertex (other than the first and second vertices of the four vertices), but rather to overlap with the vicinity of the fourth vertex located diagonally opposite the third vertex.

6. The sensor according to claim 2 or 5, wherein, The reinforcing portion does not overlap with the piezoelectric film when viewed from above.

7. The sensor according to any one of claims 1 to 6, wherein, The piezoelectric film is disposed at the corner of the retaining plate.

8. The sensor according to any one of claims 1 to 7, wherein, Multiple sets of the piezoelectric film and the reinforcing portion are arranged on the retaining plate.

9. The sensor according to any one of claims 1 to 8, wherein, The sensor also includes a piezoelectric film sensor comprising the piezoelectric film, a first electrode, and a second electrode. The piezoelectric thin film has a first main film surface and a second main film surface. The first electrode is disposed on the main surface of the first thin film and is in contact with the holding plate. The second electrode is disposed on the main surface of the second thin film and is connected to the reference potential.

10. An electronic device, wherein, This electronic device has: The sensor according to any one of claims 1 to 9; and Touch panel.

11. The electronic device according to claim 10, wherein, The electronic device also features a display panel.

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