Matsushita Electric Industrial Co., Ltd.

Katsunori Moritoki

Hiroshi Nakatsuka

Katsu Takeda

Kojiro Okuyama

Osamu Kawasaki

Takeshi Yamaguchi

Keiji Onishi

Toshiyuki Asahi

Tetsuro Otsuchi

Akihiko Namba

Kouji Kawakita

Hiroshi Kagata

Junichi Kato

Yasuhiro Sugaya

Katsumi Imada

Hiroki Sato

Yoshihiro Bessho

Kazunari Nishihara

Takeshi Masutani

Masato Sugimoto

Yukinori Sasaki

Tetsuro Shimamura

Kunihiro Fujii

Tetsuo Kawasaki

Tetsuya Furihata

Hiroshi Fukushima

Yusuke Adachi

Kouzou Murakami

Takashi Ishikawa

Kuniaki Matsushita

Akihiro Nanba

Kouji Nomura

A surface acoustic wave device which occupies a small mounting area and has a low profile, yet having an improved reliability, and can be made available at low cost. The surface acoustic wave device comprises a piezoelectric substrate, a function region formed of comb-like electrodes for exciting surface acoustic wave provided on a main surface of the piezoelectric substrate, a space formation member covering the function region, a plurality of bump electrodes provided on a main surface of the piezoelectric substrate and a terminal electrode provided opposed to the main surface of piezoelectric substrate. The bump electrode and the terminal electrode are having a direct electrical connection, and a space between piezoelectric substrate and terminal electrode is filled with resin. When the above-configured acoustic wave device is applied for a frequency filter, a resonator, in a portable telephone unit, a keyless entry or the like communication apparatus, the overall size of such apparatus can be reduced and a higher reliability is implemented.

Method for manufacturing surface acoustic wave device

A driving circuit for a piezoelectric transformer is provided, which ensures lighting of all the cold-cathode tubes connected to the piezoelectric transformer, and reduces the difference in brightness between the cathode tubes during steady lighting, thereby enhancing reliability and performance. A plurality of cold-cathode tubes connected to a secondary side of the piezoelectric transformer, and a cold-cathode tube output detector circuit connected in series to a plurality of cold-cathode tubes, for detecting an output state of the respective cold-cathode tubes are provided, and the driving of the piezoelectric transformer is controlled based on a detection signal from the cold-cathode tube output detector circuit. Because of this, the piezoelectric transformer performs the same operation as that with respect to one cold-cathode tube.

Driving circuit for piezoelectric transformer, cold-cathode tube light-emitting apparatus, liquid crystal panel and device with built-in liquid crystal panel

A driving circuit for a piezoelectric transformer is provided, which is capable of driving a piezoelectric transformer at a high efficiency and with low distortion, and being miniaturized. At the commencement of lighting a cold-cathode fluorescent tube, a digital controller fixes frequencies of first and second control signals VCand VCat a predetermined frequency and controls the phase difference therebetween so that an output power of the piezoelectric transformer becomes from substantially zero to a predetermined output power. After lighting of the cold-cathode fluorescent tube, the digital controller controls the phase difference between the first and second control signals VCand VCso that current detecting data CD substantially is matched with reference data RD.

Driving circuit and driving method for piezoelectric transformer, backlight apparatus, liquid crystal display apparatus, liquid crystal monitor, and liquid crystal TV

A low loss, small scale piezoelectric transformer, suited for a cold cathode tube load, and having a high effective coupling factor, is provided using a piezoelectric plate having a single polarization direction. Controlling the dimensions of the third electrode portionconstituting the high impedance portion makes it possible easily to adjust the capacitance of the electrostatic capacitor formed between the first electrode portionand the third electrode portion in accordance with the load. Also, the second electrode portionand the fourth electrode portionconstituting the low impedance portion are substantially equal in area and the third electrode portion and the fourth electrode portion are formed in one piece, so that energy propagation efficiency can be increased. Consequently, the effective coupling factor resulting from the electrode structure and the vibration mode can be kept high even if the capacitance is changed freely, and thus high element efficiency and a small amount of generated heat can be maintained and stress can be decreased.

Piezoelectric transformer, piezoelectric transformer unit, inverter circuit, light emission control device, and liquid crystal display device

A piezoelectric vibrator which uses lithium tantalate as a piezoelectric material and of which main vibration is thickness shear vibration. The thickness direction of the vibrator forms angle of 0&#xb0;&#xb1;5&#xb0; to the X-axis of a single crystal. The longitudinal direction of vibrator lies, with the X-axis used as a rotation axis, in direction n +57&#xb0;&#xb1;2&#xb0; clockwise from the Y-axis of the single crystal. A ratio L/H of the length L of the vibrator to the thickness H is not less than 15. A ratio Le/H of the length Le of the exciting electrode to the thickness H of the vibrator element portion is 3&#x2013;6. Accordingly, a vibrator having improved temperature characteristics and a large Q is realized.

Piezoelectric vibrator ladder-type filter using piezoeletric vibrator and double-mode piezolectric filter

A compact and high-power piezoelectric transformer is realized by using higher order longitudinal extensional mode vibrations and increasing an effective electromechanical coupling factor by a primary electrode which consists of plural electrodes.

Piezoelectric transformer

Surface acoustic wave device, method for manufacturing, and electronic circuit device

The piezoelectric transformer of the present invention has a piezoelectric element mainly formed of a piezoelectric material, primary electrodes U and D which are formed on the piezoelectric element and to which a voltage is applied, a secondary electrode which is formed on the piezoelectric element and from which a voltage higher than the voltage applied to the primary electrode is output, and a sensor electrode which is formed on the piezoelectric element and from which a voltage lower than the output voltage of the secondary electrode is output.

Piezoelectric transformer, piezoelectric transformer drive circuit, piezoelectric transformer drive method and cold cathode tube drive apparatus using piezoelectric transformer

The invention provides a method of driving a piezoelectric transformer and a power source apparatus using the same. For a circuit for driving a piezoelectric transformer which steps up a voltage input from a primary electrode by a piezoelectric effect to output the stepped up voltage from a secondary electrode, the gradient (linear differential value) of a step-up ratio at the piezoelectric transformer is detected, and the detected gradient is used to control the driving frequency for the piezoelectric transformer so that the driving frequency approaches to the resonant frequency of the piezoelectric transformer.

Method of driving a piezoelectric transformer and power source apparatus using the same

A surface acoustic wave device of the present invention includes a piezoelectric substrate, a plurality of comb electrodes for exciting a surface acoustic wave, disposed on a principal plane of the piezoelectric substrate, a plurality of bumps disposed on the principal plane, and an insulating sheet disposed so as to be opposed to the principal plane, wherein the bumps and the comb electrodes are connected electrically to each other, and the bumps penetrate through the insulating sheet.

Surface acoustic wave device, method for producing the same, and circuit module using the same

A piezoelectric element includes a piezoelectric substrate formed of a piezoelectric material and a pair of electrodes formed on a first principal plane and a second principal plane of the piezoelectric substrate, wherein thickness shear vibration occurs, and the vibration direction of the thickness shear vibration is nonparallel to the side walls of the piezoelectric substrate.

Piezoelectric element having thickness shear vibration and mobile communication device using the same

An electronic component includes a projection electrode to be bonded to a circuit board. The projection electrode is prevented from being contaminated or oxidized during a period from manufacturing of the electronic component until mounting of the component to the circuit board. Methods of manufacturing the electronic component and an electronic circuit device are also provided. The electronic component includes the projection electrode formed on a connection terminal on a substrate having a circuit element and a protective film for covering the circuit element and the projection electrode. The projection electrode is prevented from being contaminated or oxidized since the manufacturing of the electronic component until mounting thereof to the circuit board, and reliable bonding of the projection electrode to a connection terminal of the circuit board can be realized.

Electronic component, having projection electrodes and methods for manufacturing thereof

Growing community of inventors

Osaka, Japan

Katsunori Moritoki