JP2008092110A - Piezoelectric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric device packaging a variety of information data in each piezoelectric device, even if the front surface area of a lid is very small. <P>SOLUTION: The piezoelectric device has: an IC chip 19, which is not electrically connected with a piezoelectric resonance element 11 molded with resin 20, formed on a bottom surface of a recessed space 15 facing a location of one side end opposite to the other fixed side of the piezoelectric resonance element 11; and an antenna part 16 electrically connected with the IC chip 19 formed on an inner surface of the recessed space 15, the resin being partially in contact with the side end of the piezoelectric resonance element 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a piezoelectric device which is one of electronic components used in electronic equipment, and more particularly to a piezoelectric device whose size has been remarkably advanced.

  2. Description of the Related Art Conventionally, electronic devices such as portable communication devices are transmitted and received by piezoelectric vibrators, piezoelectric oscillators, or electronic devices that are used as sources of reference signals or clock signals for electronic devices or electronic components mounted on the electronic devices. Piezoelectric devices such as piezoelectric filters that block signals other than a specific frequency band signal are used.

  Such a piezoelectric device will be described by taking a piezoelectric vibrator as one of the piezoelectric devices as an example. That is, as shown in FIG. 4, a pair of element mounting pads 47 are provided on the bottom surface in the recessed space 45 formed in the container body 40. On the element mounting pad 47, a piezoelectric vibration element 41 made of a quartz material having a pair of excitation electrodes electrically connected via a conductive adhesive 43 on the front and back main surfaces is mounted. A sealing conductor pattern 42 is attached to the entire top surface of the opening side top surface of the side wall of the container body 40 that surrounds the recessed space 45 containing the vibration element 41. Mounting the piezoelectric vibration element 41 by covering the sealing conductor pattern 42 with a flat metal lid 44 and welding and joining the sealing conductor pattern 42 and the edge of the lid 44 by seam welding or the like. This is a piezoelectric vibrator 4 in which a space (concave space 45) is hermetically sealed. (For example, see Patent Document 1 below.)

  In such a piezoelectric vibrator 4, a piezoelectric element mounted inside the container body 40 via an external connection electrode terminal 49 including an input / output terminal and a ground terminal provided on the mounting side main surface of the container body 40. When an alternating voltage from the outside is applied between the excitation electrodes of the vibration element 41, vibration is caused in a predetermined vibration mode and frequency according to the form of the piezoelectric vibration element 41, and the like. Thus, a reference signal having a predetermined frequency is oscillated and output by an external oscillation circuit. Such a reference signal is used as a clock signal in an electronic device such as a portable communication device.

  Further, on the externally exposed main surface of the metal lid 44 described above, various displays relating to the piezoelectric vibrator 4 such as the resonance frequency value, manufacturer display, and manufacturing lot number of the piezoelectric vibration element 41 mounted in the recessed space. Has been.

  In addition, as a piezoelectric device other than the above-described piezoelectric vibrator, an integrated circuit including a piezoelectric vibration element and an oscillation circuit electrically connected to the piezoelectric vibration element in the concave space in the container as described above. There are a piezoelectric oscillator in which an element is mounted together, a piezoelectric filter in which a piezoelectric vibration element mounted inside functions as a filter, and the like.

The following prior arts are disclosed for the piezoelectric device including the piezoelectric vibrator and the like as described above.
JP 2002-111435 A (page 5-6, FIG. 2) JP-A-9-33228 JP 2001-185986 A

  In addition, the applicant did not come to discover prior art documents related to the present invention by the time of the filing of the application other than the prior art documents specified by the prior art document information described above.

  However, in the above-described conventional piezoelectric device, various information data such as an oscillation frequency value, a service mark indicating the manufacturer, or a manufacturing lot number related to the piezoelectric device are printed or lasered on the outer main surface of the plate-like lid. Although it is formed by etching, the area of the lid surface when the size of the piezoelectric device is significantly reduced so that the external size is 2.5 mm long, 2.0 mm wide, and 0.9 mm thick or less. Becomes very narrow, and it may be impossible to describe the various information data as described above on the lid surface so that they can be recognized with the naked eye.

  Further, when the piezoelectric vibration element is mounted in the recessed space formed in the container body, when using a so-called cantilever holding form in which one side of the piezoelectric vibration element is fixedly held, the piezoelectric vibration element is inevitably held and held. The position in the recessed space of the unfixed side edge facing one side is not constant in the thickness direction of the piezoelectric device, and there is a possibility that the vibration characteristics between the individual piezoelectric devices may vary.

  The present invention has been made in view of the above problems, and therefore, the purpose of the present invention is to mount various information data as described above on individual device bodies even when the area of the lid surface is very narrow. Another object is to provide a piezoelectric device with good characteristics.

The piezoelectric device according to the present invention includes at least a substantially rectangular parallelepiped container body formed of an insulating material and having at least one recessed space having an opening on one main surface, and near one side of the bottom surface in the recessed space. In a piezoelectric device having a structure in which a piezoelectric vibration element having a rectangular main surface is fixed to one side by being electrically and mechanically connected to a pair of element connection electrode pads formed along one side. ,
An IC chip molded with resin and not electrically connected to the piezoelectric vibration element is formed on the bottom surface in the concave space opposite to the position where the one side end facing the fixed side of the piezoelectric vibration element is disposed. An antenna portion electrically connected to the IC chip is formed on the inner surface of the recess space, and a part of the resin is in contact with the side edge portion of the piezoelectric vibration element. To do.

  In the piezoelectric device according to the present invention, in the above configuration, the specification data, manufacturing history data, or characteristic data relating to the piezoelectric device input / output by the non-contact type data reading / writing means is stored in the memory unit constituting the IC chip. At least one of them is stored.

  According to the piezoelectric device of the present invention, various information data to be recorded in each piezoelectric device is recorded and read by the non-contact type reading / writing means in the IC chip by the IC chip and the antenna portion connected thereto. Thus, even when the external size of the piezoelectric device is remarkably reduced, various information data can be recorded in each piezoelectric device. In addition, the amount of information data that can be recorded in the IC chip according to the present invention is much larger than the amount of information data described in the conventional lid, so that the characteristic data in each piezoelectric device can be recorded. For example, information data that could not be recorded conventionally can also be recorded in each piezoelectric device. Further, when the product is shipped, the information data recorded in each IC chip in a state where a plurality of piezoelectric devices are packed is read by the non-contact type reading / writing means, so that it is outside the specified specification. In the case where the piezoelectric device is mixed, foreign matters can be found significantly faster and more reliably than when individually inspected with the naked eye or the like, and the occurrence of defect complaints from users after shipment can be reduced.

  Further, the resin molding the IC chip functions as a support member that supports the side end portion (free end portion) where the piezoelectric vibration element is not fixed from the bottom surface side in the recess space, thereby supporting the piezoelectric vibration element in the recess space. It becomes possible to hold | maintain substantially in parallel with respect to the bottom face in a recessed space inside.

  Therefore, according to the present invention, various information data can be mounted on each piezoelectric device even in a piezoelectric device that has been miniaturized, and at the same time, the posture of the piezoelectric vibration element mounted inside can be well maintained. Thus, it is possible to provide a piezoelectric device having excellent vibration characteristics of the piezoelectric vibration element.

Hereinafter, embodiments of a piezoelectric device according to the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view illustrating an embodiment of a piezoelectric device according to the present invention, taking a piezoelectric vibrator as an example of a piezoelectric device as an example, and FIG. 2 shows a container body shown in FIG. (A) is a plan view viewed from the concave space opening side, and (b) is a schematic cross-sectional view taken along the virtual cutting line AA ′ described in (a). FIG. 3 is a structural diagram when a piezoelectric vibration element is mounted on the container body shown in FIG. 2, and (a) is a plan view when viewed from the opening side of the recessed space 15 before mounting the lid, (B) is a schematic sectional drawing at the time of cut | disconnecting the cover body 14 by the virtual cutting line BB 'of (a) description after mounting. FIG. 5 is a schematic cross-sectional view showing an embodiment of a piezoelectric device according to the present invention, taking as an example a piezoelectric oscillator which is one of the piezoelectric devices. In each of the drawings, a part of the structure is not shown, and some dimensions are exaggerated for the sake of clarity. In particular, the thickness dimension of each part is exaggerated.

  That is, the container body 10 in each of FIGS. 1, 2, and 3 includes, for example, a substrate 12 having a main surface shape made of an insulating material such as glass-ceramic and alumina ceramic, and an insulating material similar to the substrate 12. The outer peripheral shape is formed of a frame-shaped side wall portion 13 having the same shape as the outer peripheral shape of the main surface of the substrate 12, and the side wall portion 13 is attached to the upper main surface of the substrate 12. An element connection electrode pad 17 is formed in the form along the short side in the vicinity of one short side of the inner bottom surface of the concave space 15 constituted by the inner peripheral surface of 13, and a conductive adhesive 18 is provided on the pad. The piezoelectric vibration element 11 is configured by fixing one short side of the piezoelectric vibration element 11. In addition, as a characteristic part of the present invention, a recessed space 15 that is opposed to an unfixed short side edge of the piezoelectric vibration element 11 that faces one short side of the piezoelectric vibration element 11 that is fixed to the element connection electrode pad 17. An IC chip 19 is disposed on the inner bottom surface. Further, from the IC chip 19, a loop-shaped antenna portion 16 is formed around the inner bottom surface of the recessed space 15. Here, the upper surface of the IC chip 19 is covered with the resin 20, and the surface of the resin 20 and the side edge of the piezoelectric vibration element 11 are in contact with each other or extremely close to each other.

  The piezoelectric vibrator 1 shown in FIG. 1 and FIG. 3 (b) includes, specifically, an upper main surface of the substrate 12, an inner peripheral surface of the side wall portion 13, and a lower main surface of the lid body 14. The piezoelectric vibration element 11 is accommodated in the enclosed recess space 15, and the lid body 14 is further mounted and bonded on the opening side top surface of the side wall portion 13 so as to cover the recess space opening. The inside is hermetically sealed, and the upper main surface of the substrate 12 exposed in the recessed space 15 is connected to the excitation electrodes formed on both the front and back main surfaces of the piezoelectric vibration element 11 as described above. A pair of element connection electrode pads 17 are provided at the four corners of the lower main surface of the substrate 12 with external connection electrode terminals 21 for connection to an external mounting circuit board such as another mother board. The terminal is embedded in the conductive wiring pattern (not shown) on the surface of the substrate 12 or inside the substrate 12. And via-hole conductors (not shown) or the like, between the corresponding ones, are electrically connected to each other. Further, as described above, in the piezoelectric vibrator 1 of the present invention, the IC chip 19 is disposed at a predetermined position on the inner bottom surface of the recessed space 15. The electronic circuit network formed in the IC chip and the excitation electrode of the piezoelectric vibration element 11 are not electrically connected. The IC chip 19 includes specification data such as an oscillation frequency, a load capacitance value, and a crystal impedance value related to each piezoelectric vibrator 1, manufacturing history data such as a manufacturer name, manufacturing date, and manufacturing lot number, temperature characteristic data, Characteristic data such as low drive characteristic data is stored. An antenna portion 16 serving as a transmission antenna for transmitting / receiving data stored in or written in the IC chip 19 by an external data reading / writing transmitting / receiving means is formed in a loop shape on the inner surface of the recessed space 15. The information data transmitted / received wirelessly to / from the IC chip 19 via the antenna unit 16 is displayed on the display unit of the data reading / writing transmission / reception unit or the computer connected to the data reading / writing transmission / reception unit. It can be displayed and confirmed on the display means.

  The four external connection electrode terminals 21 provided on the lower main surface of the substrate 12 function as terminals for connecting and fixing the piezoelectric vibrator 1 to an external mounting circuit board such as a mother board. When the piezoelectric vibrator 1 is mounted on the mounting circuit board, it is electrically and mechanically connected and fixed via a conductive bonding material such as solder and the circuit wiring of the mounting circuit board.

  On the other hand, the piezoelectric vibration element 11 accommodated in the piezoelectric vibrator 1 is a piezoelectric element plate cut out at a predetermined cut angle from the artificial crystalline lens when, for example, quartz is used as the piezoelectric material constituting the piezoelectric vibration element. A pair of excitation electrodes are deposited and formed on both main surfaces with the piezoelectric element body sandwiched between the two main surfaces, and externally varying voltage is applied to the piezoelectric element plate via the pair of excitation electrodes. When applied, it vibrates at a predetermined frequency in the main vibration mode. In addition, as the piezoelectric material, lithium tantalate, lithium niobate, piezoelectric ceramics, or the like may be used.

  Furthermore, as another characteristic part of the present invention, as shown in FIGS. 1 to 3, a recessed space 15 that is opposed to a position where one short-side end portion opposite to the fixed short side of the piezoelectric vibration element 11 is disposed. Since the IC chip 19 that is not electrically connected to the piezoelectric vibration element 11 molded with the resin 20 is formed on the inner bottom surface, the short side where the IC chip 19 is not fixed to the piezoelectric vibration element 11 is formed. It is possible to hold the piezoelectric vibration element 11 substantially parallel to the bottom surface in the recess space. As a result, the stray capacitance value generated between the piezoelectric vibration element 11 and the lid 14 or the inner bottom surface of the recess space 15 varies because the holding posture of each piezoelectric vibrator is indefinite, and the characteristics differ among the individual piezoelectric vibrators. It is possible to avoid the problem of end up.

  In addition, this invention is not limited to the above-mentioned embodiment, A various change, improvement, etc. are possible in the range which does not deviate from the summary of this invention.

  For example, in the above-described embodiment, the piezoelectric vibrator has been described as an example. However, in addition, the piezoelectric vibration element and an oscillation circuit electrically connected to the piezoelectric vibration element are incorporated in the recessed space in the container. In the piezoelectric oscillator in which the circuit element is mounted and the piezoelectric filter in which the piezoelectric vibration element mounted inside functions as a filter, the resin-molded IC chip and the antenna unit are formed in the above-described embodiment, and various information By writing data into the IC chip or reading data from the IC chip in a non-contact manner, the same effects as in the present invention can be obtained. In FIG. 5, an integrated circuit element in which a problem solving means in the present invention is built in a container body 50, which includes a piezoelectric vibration element 11 and an oscillation circuit electrically connected to at least an excitation electrode formed on the piezoelectric vibration element 11. The case where it applies to the piezoelectric oscillator 5 which mounts 51 is shown.

FIG. 1 is an exploded external perspective view illustrating an embodiment of a piezoelectric device according to the present invention, taking as an example a piezoelectric vibrator that is one of the piezoelectric devices. 2 is a structural diagram of the container body shown in FIG. 1, (a) is a plan view when viewed from the recessed space opening side, and (b) is a virtual cutting line A- described in (a). It is a schematic sectional drawing at the time of cut | disconnecting by A '. FIG. 3 is a structural diagram when the piezoelectric vibration element is mounted on the container body shown in FIG. 2, and (a) is a plan view when viewed from the recessed space opening side before the lid body is placed, (B) is a schematic sectional drawing at the time of cutting | disconnecting a cover body by the virtual cutting line BB 'of (a) description after mounting. FIG. 4 shows an embodiment of a conventional piezoelectric device, taking as an example a piezoelectric vibrator which is one of the piezoelectric devices, (a) is a plan view seen from the lid side, and (b) is ( It is a schematic sectional drawing at the time of cut | disconnecting by the virtual cutting line CC 'of a) description. FIG. 5 is a schematic cross-sectional view illustrating an embodiment of a piezoelectric device according to the present invention, taking as an example a piezoelectric oscillator that is one of the piezoelectric devices.

Explanation of symbols

1 ... Piezoelectric vibrator (piezoelectric device)
DESCRIPTION OF SYMBOLS 10 ... Container body 11 ... Piezoelectric vibration element 12 ... Board | substrate 13 ... Side wall part 14 ... Cover body 15 ... Recessed space 16 ... Antenna part 17 ... Element connection electrode pad DESCRIPTION OF SYMBOLS 18 ... Conductive adhesive 19 ... IC chip 20 ... Resin 21 ... External connection electrode terminal 5 ... Piezoelectric oscillator (piezoelectric device)

Claims (2)

at least,
A substantially rectangular parallelepiped container formed of an insulating material and having at least one recessed space having an opening on one main surface;
A piezoelectric plate having a rectangular main surface shape, with one side fixed by electrical and mechanical connection to a pair of element connection electrode pads formed along the one side in the vicinity of one side of the bottom surface in the recess space. In a piezoelectric device having a structure including a vibration element,
An IC chip that is not electrically connected to the piezoelectric vibration element molded with resin on the bottom surface in the recess space opposite to the position where one side end portion facing the fixed side of the piezoelectric vibration element is disposed. And an antenna portion electrically connected to the IC chip is formed on the inner surface of the recess space, and a part of the resin is in contact with a side edge portion of the piezoelectric vibration element. A piezoelectric device characterized by that.   The memory unit constituting the IC chip stores at least one of specification data, manufacturing history data, and characteristic data related to the piezoelectric device input / output by the non-contact type data reading / writing means. The piezoelectric device according to claim 1.

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