Nihon Dempa Kogyo Co., Ltd.

Mitoshi Umeki

Ryoichi Ichikawa

Seiji Oda

Takefumi Saito

Kenichi Kikuchi

Yoshiaki Amano

Takahiro Inoue

Hiroshi Uehara

Keisuke Hirano

Kenji Shimao

Hiroyuki Sasaki

Manabu Ishikawa

Masaaki Arai

Kenji Kamezawa

Noritsugu Matsukura

Masayoshi Okazaki

An exemplary piezoelectric vibrating device includes a piezoelectric vibrating piece that vibrates when electrically energized. A first package plate has a main recess in which the piezoelectric vibrating piece is placed, and a peripheral surface surrounding the recess. A second package plate is bonded to the peripheral surface of the first package plate in airtight manner. A band of adhesive bonds the first package plate to the second package plate. The adhesive band surrounds the peripheral surface. Between the adhesive and the main recess is a band of metal film. The band of metal film prevents gas, generated from the adhesive, from flowing into the recess. The band of metal film surrounds the peripheral surface and is disposed inboard of the band of adhesive.

Piezoelectric vibrating devices and methods for manufacturing same

To provide a piezoelectric resonator that suppresses spread of a conductive adhesive and is low in cost and a method of manufacturing a piezoelectric resonator. At positions, of a base, corresponding to electrode terminals on a crystal resonating piece, projection portionsare formed by etching the base, and a metal film is formed on front surfaces of the above projection portions, and the above metal films and the electrode terminals on the above-described crystal resonating pieceare electrically connected with a conductive adhesive. The conductive adhesivesrise on side surfaces of the above-described projection portionsdue to surface tension to bring the conductive adhesivesinto a state where they do not easily flow outward, so that it is possible to suppress spread of the conductive adhesives. Further, it is possible to reduce a film thickness of the metal film to be formed on the front surfaces of the projection portions, so that the crystal resonating pieceis reduced in cost.

Piezoelectric resonator and method of manufacturing piezoelectric resonator

Piezoelectric vibrating pieces are disclosed having selectively roughened surfaces. An exemplary piece is made of a piezoelectric material configured as a piezoelectric substrate. The piece also includes at least one excitation electrode and at least one extraction electrode. The substrate has opposing main surfaces initially having low surface roughness. At least one main surface is formed in a mesa or reverse mesa manner, wherein the central region has a different thickness than the peripheral region. The central region has relatively low surface roughness (irregular unevenness), while the peripheral region has relatively high surface roughness. The excitation electrode is formed on the central region (mesa or reverse mesa) while the extraction electrode (connected to the excitation electrode) is formed on the peripheral region.

Piezoelectric vibrating pieces and devices, and methods for manufacturing same

An exemplary piezoelectric vibrating device includes a piezoelectric vibrating piece that vibrates when electrically energized, a first package plate, and a second package plate. The first package plate has a respective inner main surface defining a recess. The recess has volume and dimensions sufficient to contain at least a portion of the piezoelectric vibrating piece. The inner main surface includes a peripheral main surface that peripherally extends around the recess. The second package plate has respective inner and outer main surfaces. The inner main surface is bonded to the peripheral main surface of the first package plate using a sealing material that thus seals the piezoelectric vibrating piece inside a package formed of the first and second package plates. The sealing material includes multiple concentric bands of sealing glass and multiple concentric bands of adhesive. The sealing-glass bands and the adhesive bands circumscribe the recess and desirably are in alternating order from in to out to provide durable seals.

Piezoelectric devices exhibiting enhanced resistance to physical impacts and moisture incursion

Methods are disclosed for manufacturing piezoelectric devices. In an exemplary method a base substrate is prepared that defines multiple device bases. Multiple cutting grooves are defined on a surface of the base substrate in a grid pattern to define therebetween the size of the devices. A frame substrate is also prepared from a piezoelectric material. The frame substrate defines multiple frames surrounding respective vibrating pieces and being alignable with respective bases in the base substrate. Also prepared is a lid substrate defining multiple lids being alignable with respective frames and bases. The three substrates are aligned and bonded together such that the frame substrate is between the lid and base substrates and the surface defining the cutting grooves faces outward. The base substrate is mounted on a dicing sheet such that cutting grooves face the dicing sheet. Cutting is performed, using a dicing blade, through the sandwich from the lid substrate to the cutting grooves.

Piezoelectric devices and methods for manufacturing same

Methods are disclosed for manufacturing piezoelectric devices. An exemplary method comprises the step of bonding a lid wafer, a piezoelectric frame wafer (having a vibrating piece and a outer frame surrounding the vibrating piece), and a base wafer (having at least one wiring through-hole) together. A surface of a unit (typically ball-shaped) of eutectic metal is cleaned and then arranged on the through-hole. The unit of eutectic metal is then melted in a vacuum or inert gas environment to allow the eutectic metal to enter the through-hole.

Manufacturing methods of piezoelectric devices

An exemplary piezoelectric vibrating device includes a piezoelectric frame that supports and surrounds a tuning-fork type piezoelectric vibrating piece having a pair of vibrating arms. The device also includes a lid and a package base that are siloxane-bonded to the frame. The lid defines at least one frequency-adjustment hole extending through the thickness dimension of the lid from an inner major surface thereof (facing the frame) to an outer major surface of the lid. The package base defines at least one through-hole electrode passing via a respective electrode through-hole through the thickness of the base from an inner major surface thereof (facing the frame) to the outer major surface thereof. The electrode is connected to the piezoelectric vibrating piece. The lid and base include external electrodes, made of an electrically conductive material, that cover the through-holes and frequency-adjustment hole(s).

In the disclosed piezoelectric devices a piezoelectric frame includes a vibrating piece. An excitation electrode is formed on the vibrating piece. An outer frame portion surrounds the vibrating piece and includes an extraction electrode connected to the excitation electrode. A package base is bonded to one surface of the outer frame portion and includes a connection electrode connected to the extraction electrode. The package base includes an external terminal formed on a surface thereof opposite the surface on which the connection electrodes are formed. Through-hole conductors connected the connection electrodes with respective external terminals. A lid is bonded to an opposing surface of the piezoelectric frame. An exhaust channel is in communication with the extraction electrode adjacent the through-hole conductors.

Piezoelectric frame surrounding a piezoelectric vibrating piece and package with exhaust channel

Methods are disclosed for manufacturing piezoelectric vibrating pieces and devices including such pieces. According to an embodiment of the method, a piezoelectric vibrating piece is produced from a piezoelectric wafer. To form the piece, a profile of the piezoelectric vibrating piece is formed in a piezoelectric wafer. A first metal film (chromium; Cr) is formed on the surface of the piezoelectric piece. The chromium film is surface-oxidized to form a film having Cr foundation layer and an oxidized surface. A second metal film (gold; Au) is formed on the oxidized surface. Then, in selected regions not destined to become electrodes, the second metal film is removed, leaving electrode patterns at designated regions of the piezoelectric vibrating piece.

Surface-mounted piezoelectric devices are disclosed that include a package having a base and a lid made of a piezoelectric material or of glass. The package defines an internal cavity containing a tuning-fork type crystal vibrating piece having a pair of vibrating arms. The volume of the cavity is at least twelve times the volume of the pair of vibrating arms. Piezoelectric devices having these characteristics exhibit reduced CI degradation.

Piezoelectric devices exhibiting reduced CI degradation

A crystal unit includes: a crystal blank in which a depression which function as a vibration region is formed; first and second excitation electrodes formed on both principle surfaces, respectively, of the crystal blank in the vibration region; first and second extending electrodes provided so as to extend from the first and second excitation electrodes, respectively, toward the outer periphery of the crystal blank; and a receptacle body. Bonding of the first extending electrode with eutectic alloy at one point of the outer periphery of the crystal blank electrically and mechanically connects the crystal blank to the receptacle body with the one point as the fixed end. The second extending electrode extends as far as the position of the fixed end and is electrically connected to the receptacle body by wire bonding at the position of the fixed end.

Quartz crystal unit and holding structure for same

In a crystal oscillator having a crystal blank, and an IC chip having integrated therein an oscillation circuit, the crystal blank has a first excitation electrode disposed on its first principal surface, and an extension electrode extended from the first excitation electrode to a peripheral region of the crystal blank, and folded back to the second principal surface. A first and a second crystal connection terminal are disposed on a first principal surface of the IC chip, and the second crystal connection terminal extends to a central region on the first principal surface of the IC chip to constitute a second excitation electrode. The extension electrode is secured to the first crystal connection terminal through a bump, such that the second principal surface of the crystal blank opposes the first principal surface of the IC chip, thereby holding the crystal blank in parallel with the first principal surface of the IC chip. The crystal blank is excited by the first and the second excitation electrodes.

Surface mount crystal oscillator

A crystal unit for high frequency use includes: a crystal blank having a central portion that is used as a vibration region and a peripheral portion that surrounds the central portion and that is provided with a greater thickness than the central portion; a pair of excitation electrodes provided respectively on both major surface of the crystal blank in said vibration region; a pair of extending electrodes led out from the pair of excitation electrodes toward ends of the crystal blank, respectively; and an opposition region in which the extending electrodes overlap each other with the crystal blank interposed. Each of the extending electrodes connects to a corresponding excitation electrode over at least half of the outer circumference of the excitation electrode, and the thickness of the crystal blank is greater in the opposition region than in the vibration region.

Quartz crystal unit

A crystal unit comprises an AT-cut crystal blank, and an excitation electrode formed on each of opposing main surfaces of the crystal blank in an oscillation region of the crystal blank. The ratio b/a is 0.014 or less, and preferably 0.012 or less where a represents the thickness of the crystal blank in the oscillation region and b represents the thickness of the excitation electrode. The thickness a is typically 5 &#x3bc;m or less.

Crystal unit

A high-frequency quartz crystal unit includes a quartz crystal blank having a hole defined in at least one principal surface thereof, providing a resonating region in a portion of the crystal blank which is made thinner by the hole, excitation electrodes disposed respectively on opposite principal surfaces of the crystal blank in the resonating region, extension electrodes extending respectively from the excitation electrodes to respective first and second positions on an outer peripheral portion of the crystal blank, and a casing. The crystal blank has a fixed end electrically and mechanically connected to the casing by eutectic alloy in the first position. The crystal blank has a free end on which the extension electrodes are electrically connected to the casing by wire bonding in the second position.

Growing community of inventors

Saitama, Japan

Mitoshi Umeki