Piezoelectric device and method of using a piezoelectric device

Abstract

This invention provides a piezoelectric device that can improve security performance, and a method for using the piezoelectric device. [Solution] The piezoelectric device 100 includes an operating surface operated by an operating body and a piezoelectric element 19 located on the back side of the operating surface, and also includes an operating unit 30 that outputs a signal corresponding to the charge generated in the piezoelectric element 19 by operation via the operating surface. Therefore, the operator can input predetermined security-related information (such as a PIN) by operating the operating surface. Furthermore, the piezoelectric device 100 includes a control unit 20 that detects the signal output from the operating unit 30 and determines whether the detection information based on the detected signal matches pre-stored identification information. Therefore, if identification information that can identify each piezoelectric device 100 is pre-stored, authentication can be performed by the operator inputting detection information that matches the identification information at the operating unit 30.

Description

Technical Field

[0001] The present invention relates to a piezoelectric device and a method of using the piezoelectric device.

Background Art

[0002] Cited Reference 1 below discloses a contactless IC card provided with a vibration mechanism as a type of piezoelectric device, and a piezoelectric element or a vibration motor is used as a vibration source of the vibration mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, for example, in a piezoelectric device such as an IC card, when the user drops it, others can pick it up and use it. Therefore, it has been required to improve the security performance of the piezoelectric device.

[0005] One aspect of the present invention aims to provide a piezoelectric device capable of improving security performance and a method of using the piezoelectric device.

Means for Solving the Problems

[0006] A piezoelectric device according to one aspect of the present invention includes an operation surface operated by an operation body, and a piezoelectric body disposed on the back surface side of the operation surface, and further includes an operation unit that outputs a signal corresponding to the charge generated in the piezoelectric body by an operation via the operation surface, and a control unit that detects the signal output from the operation unit and determines whether or not detection information based on the detected signal matches identification information stored in advance.

[0007] This piezoelectric device includes an operating surface operated by an operating body, a piezoelectric element located on the back side of the operating surface, and an operating unit that outputs a signal corresponding to the charge generated in the piezoelectric element by operation via the operating surface. Therefore, the operator can input predetermined security information (such as a PIN) by operating the operating surface. Furthermore, the piezoelectric device includes a control unit that detects the signal output from the operating unit and determines whether the detected information based on the detected signal matches pre-stored identification information. Therefore, if identification information that can identify each piezoelectric device is pre-stored, authentication can be performed by the operator inputting detected information that matches the identification information at the operating unit. In other words, the control unit can authenticate that the operator is the correct operator based on the determination result. As a result, the security performance of the piezoelectric device can be improved.

[0008] The control unit may output to the operator that the detection information and identification information match. In this case, the operator can recognize that authentication has been performed correctly.

[0009] The control unit may permit other devices to perform predetermined processing if the detection information and identification information match. In this case, it is possible to prevent unauthenticated operators from executing processing on other devices.

[0010] The piezoelectric device may be a card with an operating surface. In this case, the operator can perform a simple authentication process on the spot when using the card.

[0011] The operating section may have multiple piezoelectric elements arranged along the operating surface. In this case, the operator can smoothly operate the portion of the operating surface corresponding to each piezoelectric element.

[0012] The detection information may include multiple signals from the same piezoelectric element. In this case, even if the number of piezoelectric elements is small, it is possible to set a password or the like that corresponds to a large number of patterns.

[0013] The control unit may determine the piezoelectric element corresponding to the operated part on the operating surface based on information regarding the timing of the transition from a state where the signal-based value is greater than a lower threshold to a state where it is less than or equal to the lower threshold. In this case, even if the operating unit has multiple piezoelectric elements, it is possible to prevent an operation on one piezoelectric element from being mistakenly detected as an operation on another piezoelectric element.

[0014] The control unit may determine the piezoelectric element corresponding to the operated part on the operating surface based on information regarding the timing of the transition from a state where the signal-based value is less than a threshold to a state where it is below the threshold. In this case, even if the operating unit has multiple piezoelectric elements, it is possible to prevent an operation on one piezoelectric element from being mistakenly detected as an operation on another piezoelectric element.

[0015] In one aspect of the present invention, a piezoelectric device is used by operating an operating surface with an operating body, causing a piezoelectric element located on the back side of the operating surface to output a signal corresponding to the charge. The output signal is detected, and it is determined whether the detection information based on the detected signal matches pre-stored identification information. If the detection information and the identification information match, predetermined processing is performed in another device.

[0016] The method of using this piezoelectric device is that by operating the operation surface with an operating body, the piezoelectric body arranged on the back side of the operation surface outputs a signal corresponding to the electric charge. Therefore, the operator can input predetermined information related to security (such as a password) by operating the operation surface. Furthermore, the piezoelectric device detects the output signal and determines whether the detection information based on the detected signal matches the identification information stored in advance. Therefore, if the identification information capable of identifying each piezoelectric device is stored in advance, authentication can be performed by the operator inputting detection information that matches the identification information on the operation surface. That is, the piezoelectric device can authenticate that the operator is correct based on the determination result. Also, when the detection information and the identification information match, a predetermined process is performed in other devices. In this case, it is possible to prevent an unauthenticated operator from executing the process in other devices. As described above, the security performance of the piezoelectric device can be improved.

Effects of the Invention

[0017] According to the piezoelectric device and the piezoelectric device according to one aspect of the present invention, the security performance can be improved.

Brief Description of the Drawings

[0018] [Figure 1] It is a perspective view of an IC card which is a piezoelectric device according to this embodiment. [Figure 2] It is a perspective view showing the state of use of the IC card. [Figure 3] It is an exploded view of the IC card. [Figure 4] It is a side view of the operation part. [Figure 5] It is a block diagram of the control part. [Figure 6] It is a conceptual diagram showing the processing content of the control part. [Figure 7] It is a conceptual diagram showing the processing content of the control part. [Figure 8] It is a conceptual diagram showing the processing content of the control part. [Figure 9]This is a diagram showing variations in the arrangement of the operation area.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0020] As an example of a type of piezoelectric device 100, the IC card 1 shown in FIG. 1 will be described. The IC card 1 incorporates an IC module 40 that performs arithmetic processing. The IC card 1 according to the present embodiment is non-contact type and incorporates an antenna coil 16, which will be described later. As shown in FIG. 2, the IC module 40 is held in front of (i.e., held at a predetermined distance apart from) a reader / writer 2, which is a type of power supply device, so as to be non-contact power-fed from the reader / writer 2 and communicate with the reader / writer 2. The "non-contact power supply" in this specification includes non-contact communication such as near-field wireless communication (NFC) in addition to power transmission.

[0021] The IC card 1 has a plate-like outer shape and has a front surface 1a and a back surface 1b. The IC module 40 is exposed on the front surface 1a. The IC card 1 has a laminated structure as shown in FIG. 3, and is laminated in the order of a base plate 11, an antenna sheet 12, a base material 13, and a metal plate 14 from the back surface 1b side. Each layer of the IC card 1 is adhered with a known adhesive layer (for example, a double-sided adhesive tape, an adhesive layer) not shown in the drawings.

[0022] The base plate 11 is made of a resin material that does not obstruct magnetic flux. The surface of the base plate 11 constitutes the back surface 1b of the IC card 1. The metal plate 14 is made of a metal material such as stainless steel or titanium. The surface of the metal plate 14 constitutes the front surface 1a of the IC card 1. The IC module 40 is fitted into a partial region of the metal plate 14.

[0023] The base material 13 is a film made of an insulating resin material, and can be made of acrylic, for example. The base material 13 is equipped with a voltage regulator 15, an operating circuit 18 that constitutes the operating unit 30, and a control unit 20. Details of the configuration of the operating unit 30 will be described later.

[0024] The antenna sheet 12 is made of an insulating resin material or a magnetic material. The antenna sheet 12 is provided with an antenna coil 16, which includes a coil pattern wound along its outer edge. The antenna coil 16 is electrically connected to a voltage regulator 15 on the base material 13. The antenna coil 16 is magnetically connected to a coil included in the IC module 40 on the metal plate 14.

[0025] The operating unit 30 comprises a surface 1a (see Figure 1) which serves as an operating surface operated by an operating body, and an operating circuit 18 (see Figure 3). The operating body includes, for example, a part of a living body, an object covering a part of a living body, or an object held by a living body. A part of a living body includes, for example, a fingertip of a human body. An object covering a part of a living body includes, for example, a glove worn on a human hand. An object held by a living body includes, for example, an operating member.

[0026] As shown in Figure 1, the surface 1a, which serves as the operating surface, has multiple operating areas 3. In this embodiment, the surface 1a has three operating areas 3A, 3B, and 3C. When an operating body comes into contact with the operating areas 3A, 3B, and 3C, force is applied to the operating areas 3A, 3B, and 3C from the operating body.

[0027] As shown in Figure 4, the operating circuit 18 has a plurality of piezoelectric sensors 10. The plurality of piezoelectric sensors 10 are arranged on the back surface 14b of the metal plate 14. In this embodiment, the surface of the metal plate becomes the surface 1a as the operating surface. Each of the plurality of piezoelectric sensors 10 is fixed to the back surface 14a. Each piezoelectric sensor 10 and the back surface 14a are fixed together, for example, by a bonding member 7. The bonding member 7 includes, for example, double-sided pressure-sensitive adhesive tape or adhesive. Fixing each piezoelectric sensor 10 to the back surface 14a includes, for example, bonding each piezoelectric sensor 10 to the back surface 14a. The number of piezoelectric sensors 10 corresponds to the number of operating areas 3. The number of piezoelectric sensors 10 is, for example, the same as the number of operating areas 3. In this embodiment, piezoelectric sensors 10A, 10B, and 10C are provided at positions corresponding to operating areas 3A, 3B, and 3C.

[0028] Each of the multiple piezoelectric sensors 10 (10A, 10B, 10C) includes, for example, a base plate 11, a piezoelectric element 17, and a wiring member 31. The multiple piezoelectric sensors 10 (10A, 10B, 10C) have the same configuration. Each piezoelectric sensor 10 (10A, 10B, 10C) may include a known pressure sensor.

[0029] The base plate 11 is fixed to the back surface 14a. The fixing of the base plate 11 to the back surface 14a enables the fixing of the piezoelectric sensor 10 to the back surface 14a. The fixing of the base plate 11 to the back surface 14a may include joining the base plate 11 to the back surface 14a. The base plate 11 is electrically insulated from the surface 1a, which is the operating surface. The base plate 11 is made of, for example, a conductive metallic material. The base plate 11 is made of, for example, a Ni-Fe alloy, Ni, brass, or stainless steel. The base plate 11 has a rectangular shape in plan view, for example. The base plate 11 may have a square shape in plan view, for example. The base plate 11 may have a circular shape in plan view, for example. The base plate 11 may be configured as a diaphragm. The base plate 11 includes a pair of main surfaces facing each other. One main surface is fixed to the back surface 14a. A piezoelectric element 17 is arranged on the other main surface.

[0030] Each piezoelectric element 17 includes a piezoelectric body 19 and a pair of external electrodes (not shown). Each of the plurality of piezoelectric elements 17 includes a corresponding piezoelectric body 19 from among the plurality of piezoelectric bodies 19. The piezoelectric body 19 has, for example, a rectangular parallelepiped shape. The rectangular parallelepiped shape includes a shape in which the corners and edges are chamfered, or a shape in which the corners and edges are rounded. The piezoelectric element 17 is arranged on the other main surface of the base plate 11, for example, with the center of the piezoelectric body 19 substantially aligned with the center of the base plate 11. The base plate 11 and the piezoelectric element 17 are fixed together, for example, by double-sided pressure-sensitive adhesive tape or adhesive. Fixing the base plate 11 and the piezoelectric element 17 includes, for example, joining the base plate 11 and the piezoelectric element 17.

[0031] The piezoelectric element 19 includes a pair of main surfaces that face each other. One of the pair of main surfaces included in the piezoelectric element 19 faces the base plate 11. The pair of main surfaces included in the piezoelectric element 19 have the same shape in a plan view of the piezoelectric element 17. The pair of main surfaces included in the piezoelectric element 19 have a square shape, for example, with one side having a length smaller than one side of the base plate 11. The piezoelectric element 19 has a thickness greater than the thickness of the base plate 11, for example. In a plan view of the piezoelectric element 17, the center of the piezoelectric element 19 substantially coincides with the center of the base plate 11. In a plan view of the piezoelectric element 17, each side of the piezoelectric element 19 is substantially parallel to the corresponding side of the base plate 11.

[0032] The piezoelectric body 19 consists of, for example, only a single layer of piezoelectric material. That is, the piezoelectric element 17 does not need to include internal electrodes placed within the piezoelectric body 19. The piezoelectric body 19 is made of a piezoelectric ceramic material. The piezoelectric ceramic material includes, for example, PZT[Pb(Zr,Ti)O3], PT(PbTiO3), PLZT[(Pb,La)(Zr,Ti)O3], PZN[Pb(Zn,Nb)O3], or barium titanate (BaTiO3). The piezoelectric body 19 is made of, for example, a sintered body of a ceramic green sheet containing the piezoelectric ceramic material described above. An electric charge is generated in the piezoelectric body 19 in accordance with its displacement.

[0033] Each of the pair of external electrodes is positioned on a corresponding main surface of a pair of main surfaces contained in the piezoelectric body 19. Each external electrode is, for example, in the form of a thin plate or thin film. Each external electrode contains a conductive material. The conductive material includes, for example, Ag, Pd, or an Ag-Pd alloy. Each external electrode is composed of, for example, a sintered body of a conductive paste containing the conductive material described above. One external electrode positioned on one main surface contained in the piezoelectric body 19 partially makes direct contact with the base plate 11 when the base plate 11 and the piezoelectric element 17 are fixed together. Direct contact between the base plate 11 and one external electrode enables an electrical connection between the base plate 11 and the one external electrode. The base plate 11 and the piezoelectric element 17, i.e., the base plate 11 and one external electrode, may be fixed together by, for example, a conductive adhesive or a conductive film.

[0034] The wiring member 31 includes a pair of conductors. Each of the pair of conductors is connected to a corresponding external electrode of a pair of external electrodes. Each of the pair of conductors includes one end connected to a corresponding external electrode. One end of each conductor is physically and electrically connected to a corresponding external electrode. The corresponding conductors (one end) and the external electrodes are connected by, for example, a conductive bonding material. The conductive bonding material includes, for example, solder, conductive paste, or conductive film. The conductive paste includes, for example, an anisotropic conductive paste. The conductive film includes, for example, an anisotropic conductive film.

[0035] As shown in Figure 5, when an operator presses any of the operating areas 3 on the operating surface, an electric charge is generated in the piezoelectric element 19 of the corresponding piezoelectric sensor 10 by the operation via that operating surface. Here, the operating unit 30 may include a current / voltage converter. The current / voltage converter converts the electric charge generated in the piezoelectric element 14 into a voltage signal. The operating unit 30 outputs a voltage signal as a signal corresponding to the electric charge generated in the piezoelectric element 14, for example. The voltage signal is, for example, an analog signal. The operating unit 30 may also include an amplification circuit. The amplification circuit amplifies the voltage signal converted by the current / voltage converter. The piezoelectric sensor 10 outputs a signal corresponding to the electric charge generated in the piezoelectric element 19. When operating area 3A is pressed, the piezoelectric sensor 10A outputs a signal to the control unit 20 via the wiring member 31. When operating area 3B is pressed, the piezoelectric sensor 10B outputs a signal to the control unit 20 via the wiring member 31. When operating area 3C is pressed, the piezoelectric sensor 10C outputs a signal to the control unit 20 via the wiring member 31.

[0036] The control unit 20 is configured, for example, by a computer system. The computer system physically includes, for example, a processor (arithmetic circuit), memory, a communication interface, and a data storage unit. The memory includes, for example, ROM (Read Only Memory) and RAM (Random Access Memory). The data storage unit includes, for example, an HDD (Hard Disk Drive) or an SSD (Solid State Drive). The control unit CU may be configured, for example, by a microcontroller or an integrated circuit.

[0037] The control unit 20, for example, by executing a program stored in memory on the CPU, detects multiple signals output from the operation unit 30 and performs a process to determine whether the detection information based on the detected signals matches pre-stored detection information. Through this process, the control unit 20 includes the functional elements shown in Figure 5. Specifically, the control unit 20 includes a conversion unit 21, a detection unit 22, a determination unit 23, an output unit 24, a function permission unit 26, and a storage unit 27.

[0038] The conversion unit 21 converts the analog signal input to the control unit 20 into a digital signal. The conversion unit 21 is composed of, for example, an A / D converter. The conversion unit 21 converts the voltage signal corresponding to the charge generated in the piezoelectric element 14, which is output as an analog signal from the operation unit 30, into a digital signal. The conversion unit 21 outputs the converted digital signal to the detection unit 22. Therefore, the detection unit 22 acquires voltage data, which is the digital data of the voltage signal corresponding to the charge generated in the piezoelectric element 14. The voltage data includes, for example, a value based on the signal output from the operation unit 30 (the voltage signal corresponding to the charge generated in the piezoelectric element 14).

[0039] The detection unit 22 detects the piezoelectric sensor 10 corresponding to the operation area 3 operated by the operator, among the multiple piezoelectric sensors 10, based on the signal output from the operation unit 30. That is, the detection unit 22 determines the piezoelectric element 14 among the multiple piezoelectric sensors 10 that corresponds to the operation area 3 operated by the operator, based on the signal output from the operation unit 30. The detection unit 22 compares the value based on the signal output from the operation unit 30 with a threshold. The threshold includes, for example, an upward threshold and a downward threshold. The upward threshold and the downward threshold may be the same or different. The detection unit 22 determines the piezoelectric sensor 10 (piezoelectric element 14) corresponding to the operation area 3 operated by the operator, based on, for example, information regarding the timing when the value based on the signal output from the operation unit 30 moves from a state greater than the downward threshold to a state less than or equal to the downward threshold.

[0040] Figure 6 shows an example of control processing in the control unit 20 when the operating area 3C is operated by an operating body. In this example, the rising threshold and the falling threshold are set to the same threshold Sh. When the operating area 3C is operated by an operating body, an external force is applied to the piezoelectric sensor 10C corresponding to the operating area 3C. The external force is caused by the force applied to the operating area 3C by the operating body. When the external force is applied to the piezoelectric sensor 10C corresponding to the operating area 3C, the piezoelectric element 14 contained in the piezoelectric sensor 10C corresponding to the operating area 3C is displaced, and an electric charge is generated in the piezoelectric element 14 of the piezoelectric sensor 10C. The operating unit 30 outputs a signal corresponding to the electric charge generated in the piezoelectric element 14 of the piezoelectric sensor 10C. The change in voltage data corresponding to the signal corresponding to the electric charge generated in the piezoelectric element 14 of the piezoelectric sensor 10C is shown in profile P1.

[0041] External forces may also be applied to piezoelectric sensors 10A and 10B other than piezoelectric sensor 10C. When external forces are applied to piezoelectric sensors 10A and 10B other than piezoelectric sensor 10C, the piezoelectric elements 14 contained in each of piezoelectric sensors 10A and 10B are displaced, and an electric charge is generated in each piezoelectric element 14. As shown in Figure 6, the operating unit 30 outputs a signal corresponding to the charge generated in the piezoelectric elements 14 of each piezoelectric sensor 10A and 10B. The change in voltage data corresponding to the signal corresponding to the charge generated in the piezoelectric element 14 of piezoelectric sensor 10B is shown in profile P2. The change in voltage data corresponding to the signal corresponding to the charge generated in the piezoelectric element 14 of piezoelectric sensor 10A is shown in profile P3. External forces tend to decrease as they move away from the operating region 3. The magnitude of the voltage data corresponding to the piezoelectric element 14 of piezoelectric sensor 10C is greater than the magnitude of the voltage data corresponding to the piezoelectric elements 14 of each piezoelectric sensor 10A and 10B. The magnitude of the voltage data corresponding to the piezoelectric element 14 of each piezoelectric sensor 10A is smaller than the magnitude of the voltage data corresponding to the piezoelectric element 14 of each piezoelectric sensor 10B.

[0042] The detection unit 22 sets a flag for each piezoelectric sensor 10A, 10B, and 10C if the voltage data remains above the threshold Sh for a predetermined period Tp from the moment the threshold Sh is reached. The detection unit 22 clears the flag for each piezoelectric sensor 10A, 10B, and 10C when the voltage data changes from a state greater than the threshold Sh to a state less than or equal to the threshold Sh. As shown in Figure 6, the flag is cleared latest for the voltage data corresponding to piezoelectric sensor 10C (piezoelectric body 14). Therefore, the detection unit 22 determines that piezoelectric sensor 10C (piezoelectric body 14) is the piezoelectric sensor (piezoelectric body) corresponding to the operation area 3C operated by the operator. The control unit CU determines that the operation area 3C corresponding to piezoelectric sensor 10C (piezoelectric body 14) has been operated by the operator.

[0043] The detection unit 22 may perform the processing shown in Figure 7. Figure 7 shows an example of control processing in the control unit 20 when the operation area 3C is operated by an operating body. In this example as well, the rising threshold and the falling threshold are the same threshold Sh. In Figure 7 as in Figure 6, the change in voltage data corresponding to the signal corresponding to the charge generated in the piezoelectric element 14 of the piezoelectric sensor 10C is shown in profile P1. The change in voltage data corresponding to the signal corresponding to the charge generated in the piezoelectric element 14 of the piezoelectric sensor 10B is shown in profile P2. The change in voltage data corresponding to the signal corresponding to the charge generated in the piezoelectric element 14 of the piezoelectric sensor 10A is shown in profile P3.

[0044] The detection unit 22 starts counting the time elapsed since the threshold Sh was reached when the piezoelectric sensor 10A, 10B, and 10C transitions from a state less than the threshold Sh to a state greater than or equal to the threshold Sh. The detection unit 22 stops counting the time elapsed since the threshold Sh was reached when the piezoelectric sensor 10A, 10B, and 10C transitions from a state greater than the threshold Sh to a state less than or equal to the threshold Sh. As shown in Figure 7, the counted value is the largest in the voltage data corresponding to piezoelectric sensor 10C (piezoelectric body 14). Therefore, the detection unit 22 determines that piezoelectric sensor 10C (piezoelectric body 14) is the piezoelectric sensor (piezoelectric body) corresponding to the operation area 3C operated by the operator. The control unit CU determines that the operation area 3C corresponding to piezoelectric sensor 10C (piezoelectric body 14) has been operated by the operator.

[0045] Furthermore, the detection unit 22 may determine the piezoelectric sensor 10 (piezoelectric element 14) corresponding to the operation area 3 operated by the operator, based on information regarding the timing of the transition from a state where the value based on the signal output from the operation unit OU is less than the rise threshold to a state where it is greater than or equal to the rise threshold. Figure 8 shows an example of the control processing in the control unit 20 when the operation area 3C is operated by the operator. In this example, the threshold is set to the rise threshold Sh. When the operation area 3C is operated by the operator, an external force is applied to the piezoelectric sensor 10C corresponding to the operation area 3C. The external force is caused by the force applied to the operation area 3C by the operator. When the external force is applied to the piezoelectric sensor 10C corresponding to the operation area 3C, the piezoelectric element 14 contained in the piezoelectric sensor 10C corresponding to the operation area 3C is displaced, and an electric charge is generated in the piezoelectric element 14 of the piezoelectric sensor 10C. The operation unit 30 outputs a signal corresponding to the electric charge generated in the piezoelectric element 14 of the piezoelectric sensor 10C. The change in voltage data corresponding to the signal generated in the piezoelectric element 14 of the piezoelectric sensor 10C is shown in profile P1.

[0046] External forces may also be applied to piezoelectric sensors 10A and 10B other than piezoelectric sensor 10C. When external forces are applied to piezoelectric sensors 10A and 10B other than piezoelectric sensor 10C, the piezoelectric elements 14 contained in each of piezoelectric sensors 10A and 10B are displaced, and an electric charge is generated in each piezoelectric element 14. As shown in Figure 8, the operating unit 30 outputs a signal corresponding to the charge generated in the piezoelectric elements 14 of each piezoelectric sensor 10A and 10B. The change in voltage data corresponding to the signal corresponding to the charge generated in the piezoelectric element 14 of piezoelectric sensor 10B is shown in profile P2. The change in voltage data corresponding to the signal corresponding to the charge generated in the piezoelectric element 14 of piezoelectric sensor 10A is shown in profile P3. External forces tend to decrease as they move away from the operating region 3. The magnitude of the voltage data corresponding to the piezoelectric element 14 of piezoelectric sensor 10C is greater than the magnitude of the voltage data corresponding to the piezoelectric elements 14 of each piezoelectric sensor 10A and 10B. The magnitude of the voltage data corresponding to the piezoelectric element 14 of each piezoelectric sensor 10A is smaller than the magnitude of the voltage data corresponding to the piezoelectric element 14 of each piezoelectric sensor 10B.

[0047] When the operating body is a part of the human body, as described above, signals corresponding to the charge generated in the piezoelectric elements 14 of each piezoelectric sensor 10A, 10B, and 10C tend to be output multiple times. Therefore, each profile P1, P2, and P3 tends to have multiple peaks. In the example shown in Figure 8, signals corresponding to the charge generated in the piezoelectric elements 14 of each piezoelectric sensor 10A, 10B, and 10C are output twice. Each profile P1, P2, and P3 has two peaks. In each profile P1, P2, and P3, the maximum value of the second and subsequent peaks tends to decrease compared to the maximum value of the first peak. In the second and subsequent peaks, the signals corresponding to the charge generated in the piezoelectric elements 14 of each piezoelectric sensor 10A and 10B tend to rise faster than the signals corresponding to the charge generated in the piezoelectric element 14 of piezoelectric sensor 10C.

[0048] As shown in Figure 8, the signal corresponding to the charge generated in the piezoelectric element 14 of the piezoelectric sensor 10C moves from a state where it is less than the rising threshold Sh to a state where it is greater than or equal to the rising threshold Sh as quickly as possible, and a predetermined period Tp1 elapses from the moment it becomes greater than or equal to the rising threshold Sh. Therefore, the detection unit 22 sets a flag on the piezoelectric sensor 10C at the moment when the predetermined period Tp1 has elapsed from the moment it becomes greater than or equal to the rising threshold Sh. The detection unit 22 sets the flag based on the first peak. The detection unit 22 determines that the piezoelectric sensor 10C (piezoelectric element 14) is the piezoelectric sensor (piezoelectric element) corresponding to the operating area 3C operated by the operating body.

[0049] When the detection unit 22 sets a flag, it sets a processing stop period Tp2. In the example shown in Figure 8, each profile P1, P2, and P3 has two peaks for each peak generated by the operating body. Therefore, the processing stop period Tp2 is set to last longer than the period until the value based on the signal corresponding to the charge generated in the piezoelectric body 14 of each piezoelectric sensor 10A, 10B, and 10C becomes "0" on the second occurrence. The detection unit 22 does not set flags for piezoelectric sensors 10A and 10B, excluding piezoelectric sensor 10C, until the processing stop period Tp2 has elapsed. In other words, the flags for piezoelectric sensors 10A and 10B remain unset. The detection unit 22 does not set a flag for piezoelectric sensor 10C again until the processing stop period Tp2 has elapsed. The detection unit 22 will not determine any of the piezoelectric sensors 10A, 10B, or 10C other than piezoelectric sensor 10C (piezoelectric body 14) as the piezoelectric sensor (piezoelectric body) corresponding to the operating area 3C operated by the operating body until the processing stop period Tp2 has elapsed. The control unit 20 determines that the operating area 3C corresponding to piezoelectric sensor 10C (piezoelectric body 14) has been operated by the operating body.

[0050] As shown in Figure 5, the determination unit 23 determines whether the detection information based on the signal detected by the detection unit 22 matches the pre-stored identification information. In this embodiment, the detection information can be input by operating the operation area 3. At this time, the storage unit 27 stores the identification information that is individually set for the IC card 1. The determination unit 23 queries the identification information in the storage unit 27 with the detection information related to the combination of signals input to the detection unit 22. If the detection information and the identification information are the same, the determination unit 23 determines that they match, and if the detection information and the identification information are different, it determines that they do not match.

[0051] Here, with reference to Figure 9, an example of a combination of operation areas 3 and identification information will be explained. Figure 9(a) has three operation areas 3, similar to the example shown in Figure 5. Each operation area 3 is numbered sequentially from "1" to "3". As mentioned above, a piezoelectric sensor 10, including a piezoelectric element 19, is provided at the location corresponding to each operation area 3. Each operation area 3 is arranged along the surface 1a, which is the operation surface. Here, each operation area 3 is arranged in a single line along the longitudinal direction of the card 1. As a result, the operation unit 30 has multiple piezoelectric elements 19 arranged along the operation surface. According to the example shown in Figure 9(a), a PIN code related to a combination of three numbers, "1", "2", and "3", can be set as identification information. For example, the PIN code "1, 2, 3" can be set as identification information. In this case, if the operator presses the operation areas 3 in the order "1 → 2 → 3", the detection unit 22 detects detection information in the order "1, 2, 3". Therefore, the determination unit 23 can determine that the detection information and the identification information match. Alternatively, a password of "1, 2, 3, 1" can be set as identification information. In this case, if the operator presses the operation area 3 in the order "1 → 2 → 3 → 1", the detection unit 22 will detect detection information in the order "1, 2, 3, 1". Thus, the detection information may include multiple signals from the same piezoelectric element. Here, the detection information includes two signals from the piezoelectric element 19 corresponding to "1".

[0052] Furthermore, the operation unit 30 may have two or fewer operation areas 3. As shown in Figure 9(b), the operation unit 30 may have two operation areas numbered "1" and "2". In this case, a PIN code may be set based on a combination of the two numbers "1" and "2", or a PIN code consisting of the same number, such as "1, 2, 2, 1", may be set. Also, as shown in Figure 9(c), the operation unit 30 may have an operation area with only one number, "1". In this case, a PIN code consisting of only a single number, such as "1" or "1, 1, 1", may be set. In this case, the detection information is determined by the number of times the operator taps the same operation area 3.

[0053] The operation unit 30 may have four or more operation areas 3, and may have nine operation areas 3 as shown in Figure 9(d). In this case, the operation unit 30 may have operation areas 3 arranged in multiple columns (three columns in this case). Each operation area 3 is numbered sequentially from "1" to "9". A password can be set as identification information, relating to any combination of the nine numbers "1", "2", "3", "4", "5", "6", "7", "8", and "9".

[0054] As described above, the multiple operating areas 3 are positioned along a predetermined direction at a predetermined pitch. The multiple operating areas 3 may be positioned in a single line in one dimension. Furthermore, the number of operating areas 3 is not limited and they may be positioned in a matrix in two dimensions. The multiple operating areas 3 may be positioned in a staggered pattern. The multiple operating areas 3 may be arranged randomly.

[0055] In the example shown in Figure 9, the operation area 3 was numbered. However, the information assigned to operation area 3 only needs to be visual information that allows the operator to visually recognize it as operation area 3. For example, the visual information assigned to operation area 3 may include symbols, illustrations, or colors. In addition, operation area 3 may be assigned tactile information that allows the operator to recognize it by touch, such as surface roughness, Braille, or three-dimensional patterns.

[0056] The determination unit 23 starts querying the detection information against the identification information when it detects a signal from the first piezoelectric element 19. Furthermore, each time the determination unit 23 detects a new signal, it queries the updated detection information against the identification information. If the newly detected signal differs from that in the identification information, the determination unit 23 determines that the detection information does not match the identification information. For example, if the identification information is set to a password of "1, 2, 3", the determination unit 23 will continue the query process if it detects a signal of "1" the first time and a signal of "2" the second time. However, if the determination unit 23 detects a signal other than "3" on the third attempt, it determines that the detection information does not match the identification information. On the other hand, if the determination unit 23 detects a signal of "3" on the third attempt, it determines that the detection information matches the identification information. After a certain period of time has elapsed since the operator stopped operating, the determination unit 23 may initialize the detected detection information. For example, if a period of time elapses after the detection of the second "2" without input of a third signal, the determination unit 23 initializes the detection information it had been holding, which was "1, 2". When the determination unit 23 next detects a "1" signal, it holds that "1" as the first signal. This allows the operator to start inputting again from the beginning after waiting for a certain period of time, for example, if they forget the number.

[0057] The output unit 24 outputs to the operator that the detection information and the identification information match. The output unit 24 may also output to the operator that the detection information and the identification information do not match. The output method by the output unit 24 is not particularly limited, but may be vibration, auditory information, visual information, etc. The output unit 24 may have a piezoelectric element built into the IC card 1 and use the piezoelectric element to output vibration. A piezoelectric element separate from that of the operation unit 30 may be prepared as such, or the piezoelectric element of the operation unit 30 may be used for both. The output unit 24 may output auditory information such as a buzzer sound or voice. The output unit 24 may output visual information such as light from a lamp, or characters or images from a small display. Furthermore, the output unit 24 may combine multiple output methods, such as combining vibration and sound, or combining vibration and light for output.

[0058] The function authorization unit 26 allows other devices to perform predetermined processing if the detected information and identification information match. For example, if IC card 1 is a credit card or a transportation IC card, the reader / writer 2 can perform the payment function. In this case, the function authorization unit 26 is in a standby state that does not authorize the payment function under normal circumstances. At the time of payment, if the correct PIN is entered, the function authorization unit 26 authorizes the payment processing on the reader / writer 2.

[0059] Next, the operation and effects of the piezoelectric device 100 and the method of using the piezoelectric device 100 according to this embodiment will be described.

[0060] The piezoelectric device 100 includes an operating surface operated by an operator and a piezoelectric element 19 located on the back side of the operating surface, and also includes an operating unit 30 that outputs a signal corresponding to the charge generated in the piezoelectric element 19 by operation via the operating surface. Therefore, the operator can input predetermined security-related information (such as a PIN) by operating the operating surface. Furthermore, the piezoelectric device 100 includes a control unit 20 that detects the signal output from the operating unit 30 and determines whether the detection information based on the detected signal matches pre-stored identification information. Therefore, if identification information that can identify each piezoelectric device 100 is pre-stored, authentication can be performed by the operator inputting detection information that matches the identification information at the operating unit 30. In other words, the control unit 20 can authenticate that the operator is the correct operator based on the determination result. As a result, the security performance of the piezoelectric device 100 can be improved.

[0061] The control unit 20 may output to the operator that the detection information and the identification information match. In this case, the operator can recognize that authentication has been performed correctly.

[0062] The control unit 20 may permit other devices to perform predetermined processing if the detection information and identification information match. In this case, it is possible to prevent unauthenticated operators from executing processing on other devices.

[0063] The piezoelectric device 100 may be an IC card 1 having an operating surface. In this case, the operator can perform a simple authentication process on the spot when using the IC card. For example, in the case of small-value payment cards such as transportation IC cards, payment is possible without entering a PIN on the reader side. Therefore, if the IC card 1 is lost, it may be used by someone else. There is also the risk of damage such as skimming of the IC card 1. In the IC card 1 according to this embodiment, since the IC card 1 itself has an authentication function, these fraudulent uses and skimming can be suppressed. Note that the card has enough flexibility to be deformable, unlike thin security devices such as those used by banks. The thickness of the card is set to 0.84 mm or less so that it can be inserted into a card slot.

[0064] The operating section 30 may have a plurality of piezoelectric elements 19 arranged along the operating surface. In this case, the operator can smoothly operate the portion of the operating surface corresponding to each piezoelectric element 19.

[0065] The detection information may include multiple signals from the same piezoelectric element. In this case, even if the number of piezoelectric elements 19 is small, it is possible to set a password or the like for a large number of patterns.

[0066] The control unit 20 may determine the piezoelectric element 19 corresponding to the operated part on the operating surface based on information regarding the timing of the transition from a state where the signal-based value is greater than a lower threshold to a state where it is less than or equal to the lower threshold. In this case, even if the operating unit 30 has multiple piezoelectric elements 19, it is possible to suppress the misdetection of an operation on one piezoelectric element 19 as an operation on another piezoelectric element 19.

[0067] The control unit 20 may determine the piezoelectric element 19 corresponding to the operated part on the operating surface based on information regarding the timing of the transition from a state where the signal-based value is less than the rise threshold to a state where it is below the rise threshold. In this case, even if the operating unit 30 has multiple piezoelectric elements 19, it is possible to suppress the misdetection of an operation on one piezoelectric element 19 as an operation on another piezoelectric element 19.

[0068] In this embodiment, the piezoelectric device 100 is used by operating the operating surface with an operating body, causing the piezoelectric element 19 located on the back side of the operating surface to output a signal corresponding to the charge. The output signal is detected, and it is determined whether the detection information based on the detected signal matches pre-stored identification information. If the detection information and the identification information match, predetermined processing is performed in another device.

[0069] The piezoelectric device 100 is used by operating the operating surface with an operating body, which causes the piezoelectric element 19 located on the back side of the operating surface to output a signal corresponding to the charge. Therefore, the operator can input predetermined security information (such as a PIN) by operating the operating surface. Furthermore, the piezoelectric device 100 detects the output signal and determines whether the detection information based on the detected signal matches pre-stored identification information. Therefore, if identification information that can identify each piezoelectric device 100 is pre-stored, authentication can be performed by the operator inputting detection information that matches the identification information on the operating surface. In other words, the piezoelectric device 100 can authenticate that the operator is the correct operator based on the determination result. Also, if the detection information and identification information match, predetermined processing is performed on other devices. In this case, it is possible to prevent an unauthenticated operator from executing processing on other devices. As a result, the security performance of the piezoelectric device can be improved.

[0070] As comparative examples, an operating section using a thin switch instead of the piezoelectric element 19 and a device having a capacitance-based determination function can be cited. In the case of a device that makes determinations using capacitance, the device may be affected by radio waves from the payment machine. Also, if the operator is using wet hands or gloves, they may not be able to operate the device. In contrast, the piezoelectric device 100 is not affected by radio waves from the payment machine and can be operated even with wet hands or gloves. In the case of a device using a thin switch, it may be thicker than the piezoelectric element 19 and cannot be used as a thin device such as an IC card.

[0071] The present invention is not limited to the embodiments described above.

[0072] For example, Figures 1 to 4 are merely examples of the configuration of a piezoelectric device and can be modified as appropriate without departing from the spirit of the present invention. Also, Figure 5 is merely an example of the configuration of a control unit and can be modified as appropriate without departing from the spirit of the present invention.

[0073] The operating unit 30 used a piezoelectric element, but a piezoelectric film may also be used.

[0074] In the above embodiment, one side of the IC card was the operating surface, but the back side may also be the operating surface, or both sides may be operating surfaces.

[0075] In the embodiments described above, IC cards and other cards were given as examples of piezoelectric devices, but the invention is not limited to cards. For example, a thin device may be used as the piezoelectric device, or a keychain or the like may be used.

[0076] As can be seen from the descriptions of the embodiments described above, this specification includes disclosures of the following embodiments. (Note 1) The device includes an operating surface operated by an operating body, a piezoelectric element disposed on the back side of the operating surface, and an operating unit that outputs a signal corresponding to the charge generated in the piezoelectric element by operation via the operating surface. A piezoelectric device comprising: a control unit that detects the signal output from the operation unit and determines whether the detection information based on the detected signal matches pre-stored identification information. (Note 2) The control unit outputs to the operator that the detection information and the identification information match, as described in Appendix 1. (Note 3) The piezoelectric device according to Appendix 1 or 2, wherein the control unit permits other devices to perform predetermined processing when the detection information and the identification information match. (Note 4) A piezoelectric device as described in any one of the appendices 1 to 3, which is a card having the aforementioned operating surface. (Note 5) The operating section is a piezoelectric device according to any one of the appendices 1 to 4, having a plurality of piezoelectric elements arranged along the operating surface. (Note 6) The piezoelectric device described in any one of the appendices 1 to 5, wherein the detection information includes a plurality of signals from the same piezoelectric element. (Note 7) The piezoelectric device according to any one of the appendices 1 to 6, wherein the control unit determines the piezoelectric body corresponding to the operated portion on the operating surface based on information regarding the timing of the transition from a state in which the value based on the signal is greater than a lower threshold to a state in which it is less than or equal to a lower threshold. (Note 8) The piezoelectric device according to any one of the appendices 1 to 7, wherein the control unit determines the piezoelectric body corresponding to the operated portion on the operating surface based on information regarding the timing of the transition from a state in which the value based on the signal is less than an upward threshold to a state in which it is below the upward threshold. (Note 9) By operating the operating surface with the operating body, a piezoelectric element located on the back side of the operating surface outputs a signal corresponding to the charge. The system detects the output signal and determines whether the detection information based on the detected signal matches pre-stored identification information. A method for using a piezoelectric device, wherein if the detection information and the identification information match, a predetermined process is performed in another device. [Explanation of Symbols]

[0077] 1...IC card, 19...Piezoelectric element, 20...Control unit, 30...Operating unit, 100...Piezoelectric device.

Claims

1. The device includes an operating surface operated by an operating body, a piezoelectric element disposed on the back side of the operating surface, and an operating unit that outputs a signal corresponding to the charge generated in the piezoelectric element by operation via the operating surface. A piezoelectric device comprising: a control unit that detects the signal output from the operation unit and determines whether the detection information based on the detected signal matches pre-stored identification information.

2. The piezoelectric device according to claim 1, wherein the control unit outputs to the operator that the detection information and the identification information match.

3. The piezoelectric device according to claim 1, wherein the control unit permits other devices to perform predetermined processing when the detection information and the identification information match.

4. The piezoelectric device according to claim 1, which is a card having the aforementioned operating surface.

5. The piezoelectric device according to claim 1, wherein the operating section has a plurality of piezoelectric elements arranged along the operating surface.

6. The piezoelectric device according to claim 1, wherein the detection information includes a plurality of signals from the same piezoelectric element.

7. The piezoelectric device according to claim 1, wherein the control unit determines the piezoelectric body corresponding to the operated portion on the operating surface based on information regarding the timing of the transition from a state in which the value based on the signal is greater than a lower threshold to a state in which it is less than or equal to a lower threshold.

8. The piezoelectric device according to claim 1, wherein the control unit determines the piezoelectric element corresponding to the operated portion on the operating surface based on information regarding the timing of the transition from a state in which the value based on the signal is less than an upward threshold to a state in which it is below the upward threshold.

9. By operating the operating surface with the operating body, a piezoelectric element located on the back side of the operating surface outputs a signal corresponding to the charge. The system detects the output signal and determines whether the detection information based on the detected signal matches pre-stored identification information. A method for using a piezoelectric device, wherein if the detection information and the identification information match, a predetermined process is performed in another device.

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