Kabushiki Kaisha Toshiba

Tokyo Shibaura Denki Kabushiki Kaisha

Taiyo Yuden Co., Ltd.

Fujitsu Media Devices Limited

Yasuo Ebata

Hitoshi Suzuki

Sadao Matsumura

Masayoshi Koshino

Minoru Kawase

Masanori Ueda

Tokihiro Nishihara

Shinji Taniguchi

Masafumi Iwaki

Osamu Kawachi

Naoyuki Mishima

Seiichi Mitobe

Toshiyuki Takagi

Go Endo

Youichi Masuda

Hitoshi Chiyoma

Hirohisa Tanaka

Katsuyoshi Fukuta

Kaoru Sakinada

Motoyoshi Takase

Shigefumi Morishita

Jisaburo Ushizawa

Naoki Akahori

An acoustic wave device includes a first resonator having a piezoelectric substance sandwiched between a pair of electrodes in a direction of an c-axis orientation or a polarization axis, and a second resonator that is connected in series and has another piezoelectric substance sandwiched another pair of electrodes so that one of the another pair of electrodes located in the direction of the c-axis orientation or the polarization axis is at a potential equal to that of one of the pair of electrodes of the first resonator in the direction of the c-axis orientation or the polarization axis.

Acoustic wave device, filter and duplexer

A surface acoustic wave apparatus is configured to avoid destruction from static electricity. The surface acoustic wave apparatus includes a piezoelectric substrate; a surface acoustic wave element having at least one interdigital electrode made up of a conductive film on the piezoelectric substrate; and a thin film electrically connected between terminals connecting to electrode fingers of the interdigital electrode, the thin film showing varistor characteristics formed on the piezoelectric substrate.

Elastic wave apparatus

An elastic surface wave element including first and a second two-port surface acoustic wave filters and a one-port elastic surface acoustic wave resonator filter with a single inter-digital transducer is connected via bumps to electrodes formed on a housing by face down bonding techniques. The housing has an opening section in a ground terminal electrode in a part facing the one-port elastic surface acoustic wave resonator filter.

Surface acoustic wave filter device

A surface acoustic wave filter element and a method of producing the same. The element is constructed in a manner such that a conductive film, which constitutes a plurality of electrode fingers, a bus bar connecting the electrode fingers in common, an electrode pad connected to the bus bar, etc., is formed on a piezoelectric substrate. When using the surface acoustic wave filter element with this arrangement in a high-frequency band, the thickness of the conductive film and the line width of electrodes are reduced, so that the mechanical strength is a critical problem. According to the present invention, therefore, the conductive film has a two-layer structure, including a layer containing tantalum and aluminum and a metallic layer of aluminum or an alloy consisting mainly of aluminum formed thereon, for example. The composition ratio between tantalum and aluminum is set so that the tantalum content ranges from 39% to 75% (atomic percentage). Thus, the orientation the layer of aluminum or the alloy consisting mainly of aluminum, formed on the layer containing tantalum and aluminum, is improved to increase the strength of the conductive film.

Surface acoustic wave device with a layered conductive film and method of producing the same

In an oscillator of the invention, the shape and position of each chip and wiring between the chips are optimally designed. Since a SAW element and an IC which have satisfactory reliability are arranged in the same package, the oscillator is not greatly influenced by external electromagnetic induction, is not unstably oscillated, and has satisfactory reliability.

Oscillator

A surface acoustic wave device has been developed, such as a surface acoustic wave filter in which a plurality of electroacoustic interdigital electrodes are formed, as thin films made principally of aluminum, on the surface of a Li.sub.2 B.sub.4 O.sub.7 single crystal substrate and a surface acoustic wave resonator, in which a plurality of electroacoustic interdigital electrodes and grating reflectors for reflecting the surface acoustic wave are formed, as thin films made principally of aluminum, on the surface of a Li.sub.2 B.sub.4 O.sub.7 single crystal substrate. Here, a cut angle, at which the substrate is cut from the Li.sub.2 B.sub.4 O.sub.7 single crystal, and the propagation direction of the surface acoustic wave are so set that, when the Eulerian angle representation is (90.degree..+-..lambda., 90.degree..+-..mu., 90.degree..+-..theta.), .lambda.=38.degree. to 52.degree., .mu.=0.degree. to 5.degree. and .theta.=0.degree. to 10.degree., whereby the TCD of the surface acoustic wave device is below .+-.5 ppm/.degree.C. and coupling coefficient K.sup.2 is about 1.0%, and the propagation speed suffers almost no angular dependence.

Surface acoustic wave device

An IDT is arranged at the center of a piezoelectric substrate formed of Li.sub.2 B.sub.4 O.sub.7 single crystals. Grating reflectors are arranged on either side of the IDT. The IDT and the grating reflectors are formed of 6,000 .ANG. thick aluminum films. The IDT comprises a pair of comb-shaped transducers having a plurality of electrode fingers which are arranged parallel to each other at equal distances, so that the electrode fingers of the respective transducers are alternately arranged. The grating reflectors have a plurality of reflective arrays arranged parallel to each other at equal distances. The pitch (Pg) between the reflective arrays of the grating reflectors, and the pitch (Pt) between the electrode fingers of the IDT is set to be 98.8% of half the wavelength of a surface acoustic wave in the resonance mode. Distance d between the IDT and the grating reflector is half the wavelength of a surface acoustic wave in the resonance mode. The total number of the electrode fingers of the IDT is 60 (30 pairs) and the total number of the reflective arrays of each grating reflector is 150 (the total number thereof is 300).

Surface acoustic wave resonator

A surface acoustic wave device having a lithium tatraborate single crystal substrate is proposed. An electro-mechanical coupling coefficient K.sup.2 of the substrate is about 1% so as to obtain a surface acoustic wave having sufficient practical energy. When cut angles of the substrate and a propagation direction of the surface acoustic wave are expressed by Eulerian angles (90+.lambda., 90.degree., 90.degree.), a thickness t of an electrode formed on the substrate falls within a region bounded by a dotted curve and an alternate long and short dash curve in FIG. 8. The dotted curve and the alternate long and short dash curve indicate the experimental relationship between the cut angle .lambda. and the thickness t when the TCD is set at 5 and -5 ppm/.degree.C., respectively. When the film thickness t is set within the above-mentioned range, the absolute value of the TCD is set at 5 ppm/.degree.C. or less. When the cut angle .lambda. is 25.degree., the TCD of the substrate becomes zero. Therefore, using the substrate having the above cut angle, the TCD becomes zero or almost zero in the electrode region and nonelectrode region of the surface of the substrate.

Temperature compensated surface acoustic wave device

A surface acoustic wave resonator device including a transducer and grating reflectors having an aperture length, wherein the transducer, which is disposed on a piezoelectric substrate, includes a plurality of interdigital transducers connected to each other in series and aligned to form surface acoustic wave propagation paths parallel to each other, the grating reflectors are disposed on opposite sides of the transducer on the piezoelectric substrate, the aperture length of the grating reflectors extending at least the width of said surface acoustic wave propagation paths and preferably being substantially the same effective length as that of the transducer.

Surface acoustic wave resonator device

A transmitting section includes an oscillator which has a surface acoustic wave device of which the frequency characteristic varies responding to the temperature of a base plate thereof, the oscillator generating an oscillation output of a frequency corresponding to the frequency characteristic and an antenna for transmitting the oscillation output. A receiving section includes a receiving antenna, a means for detecting the output of the receiving antenna, and a signal processing circuit for processing the output of the detecting means to generate at least one of the temperature display and control signals of the base plate of the surface acoustic wave device.

Growing community of inventors

Yokohama, Japan

Yasuo Ebata