Abstract: A surface acoustic wave device includes a piezoelectric substrate, at least one interdigital transducer (IDT) electrode provided on the piezoelectric substrate, and an insulator layer to improve a temperature characteristic arranged so as to cover the IDT electrode. When a surface of the insulator layer is classified into a first surface region under which the IDT electrode is positioned and a second surface region under which no IDT electrode is positioned, the surface of the insulator layer in at least one portion of the second surface region is higher than the surface of the insulator layer from the piezoelectric substrate in at least one portion of the first surface region by at least about 0.001?, where the wavelength of an acoustic wave is ?.

Abstract: A surface acoustic wave device has a duty that is greater than about 0.5, attenuation outside the pass band is increased, and an undesirable spurious response is effectively suppressed. The surface acoustic wave device includes an LiNbO3 substrate having Euler angles (0°±5°, ?±5°, 0°±10°), an electrode that is provided on the LiNbO3 substrate and that includes an IDT electrode primarily made of Cu, a first silicon oxide film that is provided in an area other than an area in which the electrode is arranged so as to have a thickness substantially equal to that of the electrode, and a second silicon oxide film that is arranged so as to cover the electrode and the first silicon oxide film, wherein the surface acoustic wave device utilizes an SH wave, wherein a duty D of the IDT electrode 3 is at least about 0.52, and ? of the Euler angles (0°±5, ?+5°, 0°±10°) is set so as to fall within a range that satisfies the following Inequality (1A) or (1B): (1) When 0.52?D?0.6, ?10×D+92.5?100×C???37.5×D2?57.75×D+104.

Abstract: A surface acoustic wave device includes a LiTaO3 substrate, and an IDT having a high reflection coefficient, which has a relatively high electromechanical coupling coefficient k2, and which can obtain superior resonance characteristics and/or filter characteristics. In a surface acoustic wave device in which a plurality of grooves is provided in an upper surface of a LiTaO3 substrate and an IDT having a plurality of electrode fingers made of a metal filled in the plurality of grooves, the following equation is satisfied: (?3×C44)1/2>1.95×1011, where ? represents the density of the metal defining the IDT, and C44 represents the stiffness thereof.

Abstract: A method for manufacturing a surface acoustic wave filter device includes a step of forming grooves in one principal surface of a piezoelectric substrate, a step of embedding a metallic film in the grooves to form IDT electrodes, a step of performing a process of removing a portion of the piezoelectric substrate from the one principal surface of the piezoelectric substrate, thereby forming a recessed portion including the bottom surface in which the IDT electrodes are embedded, and a step of bonding a cover member to the piezoelectric substrate.

Abstract: A surface wave sensor apparatus has a structure such that, on a first principal surface of a base substrate having first through-hole conductors, surface acoustic wave devices are bonded via thermo-compression anisotropic conductive sheets, on first principal surfaces of piezoelectric substrates of the surface acoustic wave devices, electrodes, such as IDTs, are provided, respectively. These electrodes extend toward second principal surfaces via second through-hole conductors and are provided in the piezoelectric substrates. The first through-hole conductors overlap with the second through-hole conductors with the thermo-compression anisotropic conductive sheets being disposed therebetween, respectively.

Abstract: An in-liquid-substance detection sensor that achieves size reduction and detection accuracy improvement includes a piezoelectric substrate, at least two SAW devices provided on one major surface of the piezoelectric substrate and each having at least one IDT electrode defining a sensing portion, outer electrodes provided on the other major surface of the piezoelectric substrate and electrically connected to the SAW devices through vias extending through the piezoelectric substrate, a channel-defining member provided on the one major surface of the piezoelectric substrate so as to surround the SAW devices and a region connecting the SAW devices to each other, thereby defining sidewalls of a channel, and a protective member bonded to the one major surface of the piezoelectric substrate with the channel-defining member interposed therebetween, thereby sealing the channel, the protective member having at least two through holes communicating with the channel.

Abstract: A method for manufacturing a surface acoustic wave filter device includes a step of forming grooves in one principal surface of a piezoelectric substrate, a step of embedding a metallic film in the grooves to form IDT electrodes, a step of performing a process of removing a portion of the piezoelectric substrate from the one principal surface of the piezoelectric substrate, thereby forming a recessed portion including the bottom surface in which the IDT electrodes are embedded, and a step of bonding a cover member to the piezoelectric substrate.

Abstract: A surface acoustic wave device includes a LiNbO3 substrate having a plurality of grooves formed in the upper surface thereof, an IDT electrode formed by filling the grooves with a metal, and a SiO2 layer arranged to cover an upper surface of the LiNbO3 substrate and the IDT electrode and having a substantially flat surface. The surface acoustic wave device uses a response of a Rayleigh wave. The LiNbO3 substrate has Euler angles in the range of (0°±5°, 180° to 247°, 0°±5°).

Abstract: A surface acoustic wave device which uses a Rayleigh wave as a surface acoustic wave includes an IDT electrode provided on a piezoelectric substrate composed of quartz having Euler angles of (0°±5°, 0° to 140°, 0°±40°), a piezoelectric film composed of c-axis oriented ZnO arranged so as to cover the IDT electrode, and the piezoelectric film has a convex portion provided on a surface thereof corresponding to the thickness of the ID electrode. The IDT electrode is composed of a metal material primarily including Al, Au, Ta, W, Pt, Cu, Ni, or Mo, and when the wavelength of the surface acoustic wave is represented by ?, the primary metal of the IDT electrode, a normalized thickness of the IDT electrode normalized by the wavelength of the surface acoustic wave, and a normalized thickness of the piezoelectric film normalized by the wavelength of the surface acoustic wave are preferably set within the ranges of each combination shown in Table 1.

Abstract: A surface acoustic wave sensor detects a mass load on a resonator-type surface acoustic wave filter on the basis of a change in frequency and includes an IDT electrode arranged on a piezoelectric substrate to excite surface waves, an insulating film arranged so as to cover the IDT electrode, and a reaction film which is disposed on the insulating film and which reacts with a target substance to be detected or a binding substance that binds to a target substance to be detected. The reaction film is composed of a metal or a metal oxide.

Abstract: A surface acoustic wave device which uses a Rayleigh wave as a surface acoustic wave includes an IDT electrode provided on a piezoelectric substrate composed of quartz having Euler angles of (0°±5°, 0° to 140°, 0°±40°), a piezoelectric film composed of c-axis oriented ZnO arranged so as to cover the IDT electrode, and the piezoelectric film has a convex portion provided on a surface thereof corresponding to the thickness of the ID electrode. The IDT electrode is composed of a metal material primarily including Al, Au, Ta, W, Pt, Cu, Ni, or Mo, and when the wavelength of the surface acoustic wave is represented by ?, the primary metal of the IDT electrode, a normalized thickness of the IDT electrode normalized by the wavelength of the surface acoustic wave, and a normalized thickness of the piezoelectric film normalized by the wavelength of the surface acoustic wave are preferably set within the ranges of each combination shown in Table 1.

Abstract: In a method for producing a boundary acoustic wave device that includes a first medium, a second medium, and a third medium laminated in that order, and electrodes disposed at the interface between the first medium and the second medium, the method includes the steps of preparing a laminate including the first medium, the second medium, and the electrodes disposed at the interface between the first medium and the second medium, adjusting the thickness of the second medium after the step of preparing the laminate to regulate a frequency or the acoustic velocity of a surface acoustic wave, a pseudo-boundary acoustic wave, or a boundary acoustic wave, after the adjusting step, forming the third medium different from the second medium in terms of the acoustic velocity with which the boundary acoustic wave propagates therethrough and/or in terms of material.

Abstract: A surface acoustic wave device utilizing a Rayleigh wave includes a LiNbO3 substrate having Euler angles of (0°±5°, ?±5°, 0°±10°), an electrode which is disposed on the LiNbO3 substrate and which includes an IDT electrode primarily including Au, a first silicon oxide film disposed in a region other than the region in which the above-described electrode is disposed, the first silicon oxide film having a film thickness substantially equal to the thickness of the above-described electrode, and a second silicon oxide film arranged to cover the electrode and the first silicon oxide film, wherein the film thickness of the electrode is in the range of about 0.062? to about 0.14?, where ? represents the wavelength of a surface acoustic wave, and ? of the above-described Euler angles of (0°±5°, ?±5°, 0°±10°) is in the range satisfying the following Formula (1): ?=31.72?206.92×exp(?1×TAu/0.0138)??Formula (1) where TAu is a value of Au electrode film thickness normalized with the wavelength ?.

Abstract: A boundary acoustic wave device includes a LiNbO3 substrate having a plurality of grooves provided in the upper surface thereof, electrode layers which are defined by a metal material filled in the grooves and which include IDT electrodes, and a dielectric layer, such as a SiO2 layer, provided over the upper surface of the piezoelectric substrate and the electrodes. The upper surface of the dielectric layer is flat or substantially flat. The thickness of the electrodes, ? of the Euler angles (0°, ?, ?45° to +45°) of the LiNbO3 substrate, and the thickness of the dielectric layer are within any of the ranges shown in Table 1.

Abstract: In a method for producing a boundary acoustic wave device that includes a first medium, a second medium, and a third medium laminated in that order, and electrodes disposed at the interface between the first medium and the second medium, the method includes the steps of preparing a laminate including the first medium, the second medium, and the electrodes disposed at the interface between the first medium and the second medium, adjusting the thickness of the second medium after the step of preparing the laminate to regulate a frequency or the acoustic velocity of a surface acoustic wave, a pseudo-boundary acoustic wave, or a boundary acoustic wave, after the adjusting step, forming the third medium different from the second medium in terms of the acoustic velocity with which the boundary acoustic wave propagates therethrough and/or in terms of material.

Abstract: A Lamb wave device includes a base substrate, a piezoelectric thin film which is provided on the base substrate and which has a floating portion floating above the base substrate, the floating portion having a first surface facing the base substrate and a second surface opposite to the first surface, and an IDT electrode disposed on at least one of the first and the second surfaces of the piezoelectric thin film. The piezoelectric thin film is made of LiTaO3 or LiNbO3, and the c-axis of the piezoelectric thin film is set in approximately the same direction as that of a line substantially perpendicular to the first and the second surfaces of the piezoelectric thin film, and the crystal structure of the piezoelectric thin film is a rotation twin crystal having the c-axis functioning as the rotation axis.

Abstract: A sensor for detecting a substance in liquid includes a sensing oscillation circuit and a reference oscillation circuit. The sensing oscillation circuit includes a sensing SAW element in which a reaction film arranged so as to cover at least one IDT and to react with a substance in liquid is disposed and a first amplifier circuit. The reference oscillation circuit includes a reference SAW element and a second amplifier circuit. The reference SAW element includes at least one IDT and no reaction film. The oscillation frequency of the sensing oscillation circuit and the oscillation frequency of the reference oscillation circuit are separated by at least about 200×k2 (ppm), where k2 (%) is the electromechanical coupling coefficient of a piezoelectric substrate used in each of the sensing SAW element and the reference SAW element.

Abstract: A surface acoustic wave device includes a LiNbO3 substrate having a plurality of grooves formed in the upper surface thereof, an IDT electrode formed by filling the grooves with a metal, and a SiO2 layer arranged to cover an upper surface of the LiNbO3 substrate and the IDT electrode and having a substantially flat surface. The surface acoustic wave device uses a response of a Rayleigh wave. The LiNbO3 substrate has Euler angles in the range of (0°±5°, 180° to 247°, 0°±5°).

Abstract: A surface acoustic wave device has high power withstanding performance and is able to effectively suppress an undesirable spurious response. The surface acoustic wave device includes an LiNbO3 substrate having Euler angles (0°±5°, ?±5°, 0°±10°), an electrode that is disposed on the LiNbO3 substrate and that has an IDT electrode made mainly from Cu, a first silicon oxide film that is disposed in an area other than an area in which the electrode is disposed to have a thickness equal to that of the electrode, and a second silicon oxide film that is disposed so as to cover the electrode and the first silicon oxide film, wherein the surface acoustic wave device utilizes an SH wave, wherein a duty D of the IDT electrode is less than or equal to about 0.49, and ? of the Euler angles (0°±5°, ?±5°, 0°±10°) is set to fall within a range that satisfies the following inequality: ?10×D+92.5?100×C???37.5×D2?57.75×D+104.075+5710×C2?1105.7×C+45.

Abstract: A surface acoustic wave device has a duty that is greater than about 0.5, attenuation outside the pass band is increased, and an undesirable spurious response is effectively suppressed. The surface acoustic wave device includes an LiNbO3 substrate having Euler angles (0°±5°, ?±5°, 0°±10°), an electrode that is provided on the LiNbO3 substrate and that includes an IDT electrode primarily made of Cu, a first silicon oxide film that is provided in an area other than an area in which the electrode is arranged so as to have a thickness substantially equal to that of the electrode, and a second silicon oxide film that is arranged so as to cover the electrode and the first silicon oxide film, wherein the surface acoustic wave device utilizes an SH wave, wherein a duty D of the IDT electrode 3 is at least about 0.52, and ? of the Euler angles (0°±5, ?+5°, 0°±10°) is set so as to fall within a range that satisfies the following Inequality (1A) or (1B): (1) When 0.52?D?0.6, ?10×D+92.5?100×C???37.5×D2?57.75×D+104.