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  Piezoelectric composite device, method of manufacturing same, method of controlling same, input-output device, and electronic deviceUSPTO Application #: 20060238069Title: Piezoelectric composite device, method of manufacturing same, method of controlling same, input-output device, and electronic device Abstract: Disclosed herein is a piezoelectric composite device including: a feeding electrode; a common electrode; a signal detecting electrode; a first piezoelectric element joined between the feeding electrode and the common electrode; and a second piezoelectric element joined between the common electrode and the signal detecting electrode; a predetermined voltage being supplied between the feeding electrode and the common electrode; and a force detection signal based on an external force being extracted from the detecting electrode. (end of abstract) Agent: Sonnenschein Nath & Rosenthal LLP - Chicago, IL, US Inventors: Shigeaki Maruyama, Junichi Sekine, Ivan Poupyrev USPTO Applicaton #: 20060238069 - Class: 310316010 (USPTO) The Patent Description & Claims data below is from USPTO Patent Application 20060238069. Brief Patent Description - Full Patent Description - Patent Application Claims
RELATED APPLICATION DATA [0001] This application is divisional of U.S. patent application Ser. No. 11/193,238, filed Jul. 29, 2005, which is incorporated herein by reference to the extent permitted by law. This application claims the benefit of priority to Japanese Patent Application No. JP 2004-227053 filed in the Japanese Patent Office on Aug. 3, 2004, which also is incorporated herein by reference to the extent permitted by law. BACKGROUND OF THE INVENTION [0002] The present invention relates to a piezoelectric composite device, a method of manufacturing the same, a method of controlling the same, an input-output device, and an electronic device that are suitable for application to portable telephones, digital cameras, portable terminals, remote controllers and the like having a tactile input function. [0003] The present invention relates particularly to a piezoelectric composite device including a first piezoelectric element joined between a feeding electrode and a common electrode; and a second piezoelectric element joined between the common electrode and a signal detecting electrode; wherein a predetermined voltage is supplied between the feeding electrode and the common electrode, and a force detection signal based on an external force is extracted from the detecting electrode, so that the piezoelectric composite device can be provided which combines a piezoelectric bimorph type actuator vibrating on the basis of the predetermined voltage supplied between the feeding electrode and the common electrode with a force detecting sensor outputting the force detection signal based on the external force. [0004] There have recently been more and more cases where users (operators) use a digital camera having multiple operation modes to photograph a subject, and capture various contents into a portable terminal such as a portable telephone, a PDA (Personal Digital Assistant) or the like and use the various contents. The digital camera and the portable terminal and the like have an input-output device. A touch panel that combines input section such as a keyboard, various keys, a JOG dial and the like with a display unit, for example, is often used for the input-output device. [0005] In addition, an input-output device combined with an actuator has been developed. In the actuator, piezoelectric elements having different amounts of distortion in two or more layers, or piezoelectric elements and a non-piezoelectric element are bonded to each other, and a bend deformation of the bonded object which deformation is caused by a difference in the amounts of distortion of both the elements when a voltage is applied to the piezoelectric elements is used dynamically. So-called bimorph actuators, unimorph actuators, disk actuators and the like (hereinafter referred to collectively as piezoelectric bimorph type actuators) are often used as the actuator. [0006] FIG. 26 is a perspective view of an example of structure of a multilayer piezoelectric bimorph type actuator 300 according to a conventional example. The multilayer piezoelectric bimorph type actuator 300 shown in FIG. 26 is formed by bonding together laminated piezoelectric substance groups 4a and 4b that elongate and contract respectively in opposite directions to each other on both sides of a central electrode 13 as a neutral surface of bend deformation. A metal sheet of stainless steel or the like is generally used for the central electrode 13. Leads L1 and L2 are connected to the central electrode 13 and an upper part surface electrode 11 or a lower part surface electrode 12. The upper part surface electrode 11 and the lower part surface electrode 12 are used in a state of being short-circuited by a short-circuit line L0. The actuator 300 is characterized by allowing lower-voltage driving as compared with a single-layer piezoelectric actuator. [0007] FIG. 27 is a sectional view showing an example of a laminated structure of the multilayer piezoelectric bimorph type actuator 300. FIG. 27 is a sectional view taken along a line Y1-Y2 of FIG. 26 showing the actuator 300. The multilayer piezoelectric bimorph type actuator 300 shown in FIG. 27 has the laminated piezoelectric substance group 4a and the laminated piezoelectric substance group 4b. Piezoelectric elements within the same laminated piezoelectric substance group 4a deform in the same direction, and piezoelectric elements within the same laminated piezoelectric substance group 4b deform in the same direction. The laminated piezoelectric substance group 4a and the laminated piezoelectric substance group 4b deform in opposite directions to each other. The actuator 300 thereby performs bend deformation. In order to drive the actuator 300, power is supplied with the surface electrodes (upper and lower) 11 and 12 at outermost surfaces short-circuited and with the leads L1 and L2 connected to the upper part surface electrode 11 or the lower part surface electrode 12 and the central electrode 13, as shown in FIG. 26. [0008] The actuator 300 can be used as a force detecting sensor as reverse action of the actuator 300. In this case, a voltage generated by a deformation of the actuator 300 due to an external force is taken out from the above-mentioned leads L1 and L2 to the outside. Each of the laminated piezoelectric substance groups 4a and 4b includes piezoelectric elements in the form of layers and internal electrode layers (main electrodes) IE1 to IE16 formed such that the piezoelectric elements are sandwiched between the internal electrode layers IE1 to IE16. These internal electrode layers IE1 to IE16 are connected within the actuator. Generally, in this internal connection, alternate layers are connected to each other by a method using via holes or an actuator side part formed with the internal electrodes exposed, for example, and the piezoelectric elements are used in electrically parallel connection with each other. The internal connection cannot be changed from the outside. This is because the internal connection is not drawn out to the outside of the actuator. [0009] In relation to an electronic device having this kind of piezoelectric actuator, for example, in Japanese Patent Laid-Open No. 2004-94389 (pages 4 and 5, FIG. 11) (hereinafter referred to as Patent Document 1), discloses an input-output device and an electronic device. This electronic device includes an input-output device having a multilayer piezoelectric bimorph type actuator and a touch panel. The multilayer piezoelectric bimorph type actuator feeds back a different tactile sense to a user through the touch panel according to a type of information. The electronic device being thus formed, when the user performs an input operation on the touch panel using the sense of touch, a tactile feedback in response to the input operation in accordance with a type of information can be surely provided to the user. SUMMARY OF THE INVENTION [0010] The input-output device using the multilayer piezoelectric bimorph type actuator 300 according to the conventional example has the following problems. [0011] i. When the multilayer piezoelectric bimorph type actuator 300 is used as a force detecting sensor, the force detecting sensor needs to be formed by a discrete structure separate from and independent of a structure in which the multilayer piezoelectric bimorph type actuator 300 is used as an actuator. Hence, the two structures of the force detecting sensor and the actuator need to be attached to the input-output device, thus requiring more mounting space as compared with a case where the structures are integrated into one structure. [0012] ii. When an electronic device having an input-output device as disclosed in Patent Document 1 provides a tactile sense to a user and detects the pressing force of the user or the like at the same time, and the multilayer piezoelectric bimorph type actuator 300 is to be applied, it is desirable that the function of a force detecting sensor and the function of an actuator be used simultaneously. However, a difficulty is involved in integrating the two structures described above into one structure. It is therefore difficult to realize the two functions by one structure when the structure of the multilayer piezoelectric bimorph type actuator 300 in the conventional form is used as it is. [0013] iii. Incidentally, when the function of a force detecting sensor and the function of an actuator are to be used simultaneously with the structure of the multilayer piezoelectric bimorph type actuator 300 in the conventional form used as it is, a command voltage for driving the actuator is included in a voltage detected by the force detecting sensor. As compared with this driving command voltage, the voltage (sensor output signal) varied by external force is low, so that the separation of the voltages is technically difficult. In addition to this, the addition of a complex circuit is expected, which will be disadvantageous from a viewpoint of size and cost of the actuator. [0014] Accordingly, the present invention solves the above-described problems, and it is desirable to provide a piezoelectric composite device, a method of manufacturing the same, a method of handling the same, a method of controlling the same, an input-output device, and an electronic device that enable a laminate in which one or more lead electrodes and piezoelectric elements are laminated to function both as an actuator and as a force detecting sensor. [0015] According to an embodiment of the present invention, there is provided a piezoelectric composite device including: a feeding electrode; a common electrode; a signal detecting electrode; a first piezoelectric element joined between the feeding electrode and the common electrode; and a second piezoelectric element joined between the common electrode and the signal detecting electrode; a predetermined voltage being supplied between the feeding electrode and the common electrode; and a force detection signal based on an external force being extracted from the detecting electrode. [0016] The first piezoelectric composite device according to the embodiment of the present invention includes the first piezoelectric element joined between the feeding electrode and the common electrode, and the second piezoelectric element joined between the common electrode and the signal detecting electrode. With this laminated structure as a precondition, a predetermined voltage is supplied between the feeding electrode and the common electrode, and a force detection signal based on an external force is extracted from the detecting electrode. [0017] It is thus possible to provide the piezoelectric composite device which combines a piezoelectric bimorph type actuator vibrating on the basis of the predetermined voltage supplied between the feeding electrode and the common electrode, and a force detecting sensor outputting the force detection signal based on the external force. [0018] According to an embodiment of the present invention, there is provided a first method of manufacturing a piezoelectric composite device, the method including: a step of joining a first piezoelectric element between a feeding electrode and a common electrode; a step of joining a second piezoelectric element between the common electrode and a signal detecting electrode; a step of connecting leads for supplying a predetermined voltage to each of the feeding electrode and the common electrode; and a step of connecting leads for extracting a force detection signal based on an external force to each of the common electrode and the signal detecting electrode. [0019] According to the first method of manufacturing a piezoelectric composite device according to the embodiment of the present invention, it is possible to manufacture the piezoelectric composite device which combines a piezoelectric bimorph type actuator vibrating on the basis of the predetermined voltage supplied between the feeding electrode and the common electrode, and a force detecting sensor outputting the force detection signal based on the external force. [0020] According to an embodiment of the present invention, there is provided a first method of controlling a piezoelectric composite device, the piezoelectric composite device including a feeding electrode, a common electrode, a signal detecting electrode, a first piezoelectric element joined between the feeding electrode and the common electrode, and a second piezoelectric element joined between the common electrode and the signal detecting electrode, wherein a control device connected to each of the feeding electrode, the common electrode, and the signal detecting electrode is provided, and the control device supplies power between the feeding electrode and the common electrode according to a preset control signal and detects a force detection signal from the signal detecting electrode. [0021] According to the first method of controlling a piezoelectric composite device according to the embodiment of the present invention, the control device is connected to each of the feeding electrode, the common electrode, and the signal detecting electrode. The control device supplies power between the feeding electrode and the common electrode according to a preset control signal and detects a force detection signal from the signal detecting electrode. Continue reading... Full patent description for Piezoelectric composite device, method of manufacturing same, method of controlling same, input-output device, and electronic device Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Piezoelectric composite device, method of manufacturing same, method of controlling same, input-output device, and electronic device patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. 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