Abstract: A surface acoustic wave device includes a Y-cut, X-propagation LiTaO3 substrate, at least one interdigital transducer provided on the LiTaO3 substrate and made of Al or a metal containing Al as a major component, and an SiO2 film provided on the surface of the LiTaO3 substrate so as to cover the interdigital transducer, wherein the thickness Hs of the SiO2 film normalized by the wavelength ? of a surface acoustic wave and the cut angle ? of the LiTaO3 substrate are set to be in any one of the ranges represented by formulae (1) to (8): in the case of 0.00<Hs?0.05, 30°<?<36°??(1) in the case of 0.05<Hs?0.10, 29°<?<36°??(2) in the case of 0.10<Hs?0.15, 28°<?<36°??(3) in the case of 0.15<Hs?0.20, 27°<?<36°??(4) in the case of 0.20<Hs?0.25, 26°<?<36°??(5) in the case of 0.25<Hs?0.30, 25°<?<35°??(6) in the case of 0.30<Hs?0.35, 23°<?<34°??(7) in the case of 0.35<Hs?0.

Abstract: In a method of manufacturing a surface acoustic wave device using a Shear Horizontal type surface acoustic wave, at least one interdigital transducer (IDT) is made of a material having a larger mass-load effect than that of aluminum. The metallization ratio of the IDT and the normalization film thickness h/? of the IDT are controlled such that ripple caused by a transversal mode wave is about 1.5 dB or less, where “h” indicates the film thickness of the electrodes and “h” indicates the wavelength of a surface acoustic wave.

Abstract: A surface acoustic wave apparatus has an improved frequency temperature characteristic due to an arrangement of a SiO2 film on an IDT such that cracks in the SiO2 film surface are prevented from occurring, desired characteristics are reliably achieved, the electromechanical coefficient is increased, and the attenuation constant &agr; is reduced. The surface acoustic wave apparatus includes at least one IDT primarily including Cu and arranged on a 23° to 46°-rotated Y plate LiTaO3 substrate. The SiO2 film is arranged on the LiTaO3 substrate so as to cover the at least one IDT.

Abstract: A surface acoustic wave device includes a piezoelectric substrate and interdigital electrodes disposed on the piezoelectric substrate, wherein each of the interdigital electrodes includes a main electrode layer made of Cu or an alloy that has Cu as its main component. The surface acoustic wave device also includes a tightly adhering layer which is disposed between the main electrode layer and the piezoelectric substrate and whose main component is NiCr, or a tightly adhering layer whose main component is Ti and whose film thickness is within a range of about 18 nm to about 60 nm.

Abstract: A surface acoustic wave device includes a piezoelectric substrate and interdigital electrodes disposed on the piezoelectric substrate, wherein each of the interdigital electrodes includes a main electrode layer made of Cu or an alloy that has Cu as its main component. The surface acoustic wave device also includes a tightly adhering layer which is disposed between the main electrode layer and the piezoelectric substrate and whose main component is NiCr, or a tightly adhering layer whose main component is Ti and whose film thickness is within a range of about 18 nm to about 60 nm.

Abstract: A surface acoustic wave device includes a piezoelectric plate and at least one interdigital electrode provided on the piezoelectric plate. The interdigital electrode includes a first metallic thin film and a second metallic thin film laminated on the first metallic thin film and containing tantalum as a principal component, and at least a portion of the tantalum of the second metallic thin film is &agr;-tantalum.

Abstract: An end-surface reflection type surface acoustic wave filter is capable of increasing an attenuation amount outside a pass band while insertion loss characteristics are not seriously deteriorated. The filter is a longitudinally coupled resonator type surface acoustic wave filter using an SH type surface acoustic wave, which has first and second grooves formed in a piezoelectric substrate at the top surface thereof so as to be substantially parallel to each other and spaced from each other by a predetermined distance. In addition, IDTs which are provided between the grooves for defining the longitudinally coupled resonator type surface acoustic wave filter, reflection end-surfaces disposed on side surfaces of the first and the second grooves at the IDT sides, and one of a resin-coating layer and a protective layer made of SiO2, are provided on the top surface of the piezoelectric substrate.

Abstract: In an optical head for writing and reading data on optical discs (mainly CDs and DVDs) with various specifications using different light source wavelengths, the effective light beam size for the light from each light source differs. This leads to a drop in optical efficiency for the light of a narrower effective beam size. This problem is overcome by providing a dichroic beam expander between the light sources and an objective lens, the dichroic beam expander comprising a substrate with an N-stage step- or sawtooth-shaped blazed diffraction grating formed on both sides thereof. The size of the light beams from the two light sources with different wavelengths is increased or decreased in a wavelength-selective manner, so that the light from each light source can be utilized at high efficiencies.

Abstract: An end-surface reflection type surface acoustic wave filter is capable of increasing an attenuation amount outside a pass band while insertion loss characteristics are not seriously deteriorated. The filter is a longitudinally coupled resonator type surface acoustic wave filter using an SH type surface acoustic wave, which has first and second grooves formed in a piezoelectric substrate at the top surface thereof so as to be substantially parallel to each other and spaced from each other by a predetermined distance. In addition, IDTs which are provided between the grooves for defining the longitudinally coupled resonator type surface acoustic wave filter, reflection end-surfaces disposed on side surfaces of the first and the second grooves at the IDT sides, and one of a resin-coating layer and a protective layer made of SiO2, are provided on the top surface of the piezoelectric substrate.

Abstract: In a manufacturing method for a SAW apparatus a first insulating layer is formed on the entire surface of a piezoelectric LiTaO3 substrate. By using a resist pattern used for forming an IDT electrode, the first insulating layer in which the IDT electrode is to be formed is removed. An electrode film made of a metal having a density higher than Al or an alloy primarily including such a metal is disposed in the area in which the first insulating layer is removed so as to form the IDT electrode. The resist pattern remaining on the first insulating layer is removed. A second insulating layer is formed to cover the first insulating layer and the IDT electrode.

Abstract: In a surface acoustic wave device, electrode films constituting at least one IDT are disposed on a piezoelectric substrate, and an SiO2 film is arranged on the piezoelectric substrate so as to cover the electrode films. The film-thickness of the electrode films is in the range of about 1% to about 3% of the wavelength of an excited surface acoustic wave.

Abstract: A surface acoustic wave device with improved reflection characteristics, in which an insulating film is formed so as to cover an electrode film, and the electrode film is made from Al or an Al alloy, includes a piezoelectric substrate, an electrode film which is formed of Al or an alloy including Al as a major component on the piezoelectric substrate and which defines at least one interdigital transducer, and an insulating film arranged on the piezoelectric substrate so as to cover the electrode film, the average density of the electrode film is less than or equal to about 1.5 times the density of the insulating film, wherein the top surface of the insulating film is planarized.

Abstract: An end-surface reflection type surface acoustic wave filter is capable of increasing an attenuation amount outside a pass band while insertion loss characteristics are not seriously deteriorated. The filter is a longitudinally coupled resonator type surface acoustic wave filter using an SH type surface acoustic wave, which has first and second grooves formed in a piezoelectric substrate at the top surface thereof so as to be substantially parallel to each other and spaced from each other by a predetermined distance. In addition, IDTs which are provided between the grooves for defining the longitudinally coupled resonator type surface acoustic wave filter, reflection end-surfaces disposed on side surfaces of the first and the second grooves at the IDT sides, and one of a resin-coating layer and a protective layer made of SiO2, are provided on the top surface of the piezoelectric substrate.

Abstract: In a surface acoustic wave device using a Shear Horizontal type surface acoustic wave, at least one interdigital transducer (IDT) is made of a material having a larger mass-load effect than that of aluminum. The metallization ratio of the IDT and the normalization film thickness h/&lgr; of the IDT are controlled such that ripple caused by a transversal mode wave is about 0.5 dB or less, where “h” indicates the film thickness of the electrodes and “&lgr;” indicates the wavelength of a surface acoustic wave.

Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a current flows in the intermediate layer. The film surfaces of all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Abstract: A method for manufacturing a surface acoustic wave apparatus decreases a specific resistance of an electrode film by removing hydrogen occluded in the electrode film that is primarily composed of tantalum, so that the device properties are stabilized. An electrode film primarily composed of tantalum is formed on a piezoelectric substrate. Subsequently, this electrode film is heat-treated in a vacuum at a temperature of about 200° C. to about 700° C. for several hours. Thereafter, the electrode film is patterned so as to produce an interdigital electrode transducer.

Abstract: A surface acoustic wave device includes a Y-cut, X-propagation LiTaO3 substrate, at least one interdigital transducer provided on the LiTaO3 substrate and made of Al or a metal containing Al as a major component, and an SiO2 film provided on the surface of the LiTaO3 substrate so as to cover the interdigital transducer, wherein the thickness Hs of the SiO2 film normalized by the wavelength &lgr; of a surface acoustic wave and the cut angle &thgr; of the LiTaO3 substrate are set to be in any one of the ranges represented by formulae (1) to (8):

Abstract: A surface acoustic wave device has first and second surface acoustic wave filter elements which are arranged on a surface acoustic wave substrate so as to define a filter device having a two-stage configuration. A free surface portion is provided by forming a perforation in an inter-stage connecting portion connecting the first and second surface acoustic wave filter elements.

Abstract: The magnetoresistance effect element is of a multilayered structure having at least magnetic layers and an intermediate layer of an insulating material, a semiconductor or an antiferromagnetic material against the magnetic layers, and the magnetoresistance effect element has terminals formed at least on the opposite magnetic layers, respectively, so that a all the magnetic layers constituting the magnetoresistance effect element are opposed substantially at right angles to the recording surface of a magnetic recording medium. Therefore, the area of the magnetic layers facing the recording surface of the magnetic recording medium can be extremely reduced, and thus the magnetic field from a very narrow region of the high-density recorded magnetic recording medium can be detected by the current which has a tunneling characteristic and passes through the intermediate layer.

Abstract: In a surface acoustic wave device using a Shear Horizontal type surface acoustic wave, at least one interdigital transducer (IDT) is made of a material having a larger mass-load effect than that of aluminum. The metallization ratio of the IDT and the normalization film thickness h/&lgr; of the IDT are controlled such that ripple caused by a transversal mode wave is about 0.5 dB or less, where “h” indicates the film thickness of the electrodes and “&lgr;” indicates the wavelength of a surface acoustic wave.