Abstract: To realizing a filter which is capable of properly controlling the passband, and the attenuation pole of a surface acoustic wave filter, a surface acoustic wave filter connected in a ladder type with the surface acoustic wave resonators 104, 105 has an element 106 which changes in capacity by voltage to be impressed and is connected in series with a resonator 105 connected in parallel to the signal line 100.

Abstract: A surface acoustic wave device is manufactured by directly or indirectly bonding a lid to a substrate having a surface acoustic wave element to seal the element under the lid. The lid is made of at least one material selected from the group comprising lithium niobate, lithium tantalete, lithium borate, glass and quartz. The substrate is made of at least one material selected from the group comprising quartz, lithium niobate, lithium tantalete and lithium borate.

Abstract: A surface acoustic wave device has a main substrate; a comb-like electrode formed on one of the main surfaces of said main substrate; and a supplementary substrate joined with the other main surface of said main substrate, wherein said supplementary substrate has a smaller thermal expansion coefficient and a larger thickness than said main substrate.

Abstract: A compact, low height, low cost, and high reliability surface acoustic wave device, and its method of manufacture. The surface acoustic wave device consists of a substrate, a comb-electrode disposed on the main surface of the substrate, plural electrode pads disposed around the comb-electrode, protecting means covering the comb-electrode through a closed space produced by combining the comb-electrode and the electrode pads with the substrate by using substantially covalent bonding force acting between conductive bumps formed on the electrode bumps, a conductive adhesive layer disposed at least on the top of the conductive bumps, and a package adhered on the conductive bumps by means of the conductive adhesive, and insulation adhesive filled into the package contacting the conductive adhesive, the conductive bumps, and the protective means.

Abstract: A surface acoustic wave filter is provided which performs balanced signal/unbalanced signal conversion. The input and output impedances are different from each other. In a surface acoustic wave filter of the longitudinal mode type, a signal is applied to two terminals of an input interdigital transducer, or a signal is output from two terminals of an output interdigital transducer, thereby consituting a balanced type filter. The aperture length of the input interdigital transducer is different from that of the output interdigital transducer.

Abstract: The present invention relates to an electronic part used for mobile communications apparatuses and the like, and more particularly to an electronic part, such as an acoustic surface-wave device, a piezoelectric ceramic device or the like, which requires an oscillation space near the surface of the functional device chip thereof, and a method of production thereof. With this method, a space retainer for forming a sealed space at the functional portion of the chip can be hermetically sealed and have high moisture resistance, and the process of forming the space retainer can be carried out easily.

Abstract: 36.degree. -rotated Y-cut X-propagation lithium niobate substrate (LiNbO.sub.3) was used as a piezoelectric substrate to compose a surface acoustic wave filter and is connected with a dielectric filter in series. The dielectric filter having a sign of the frequency temperature characteristic which is opposite to that of the surface acoustic wave filter was used. Accordingly, a high frequency filter, comprising a surface acoustic filter and a dielectric filter connected in series, which can secure sufficient attenuation without an increase in the insertion loss within the band can be provided.

Abstract: The present invention provides surface acoustic wave devices which do not require a balanced-to-unbalanced transformer circuit regardless of the type of the peripheral circuits of the balanced type surface acoustic wave filter, i.e. a balanced type device or an unbalanced type. A transmitting interdigital transducer and a receiving interdigital transducer are formed on a substrate comprising 41.degree. Y cut-X propagation lithium niobate. A balanced type surface acoustic wave filter is formed on a substrate comprising 36.degree. Y cut-X propagation lithium tantalate. The balanced type surface acoustic wave filter comprises two series-arm surface acoustic wave resonators and two crossed-arm surface acoustic wave resonators connected in a lattice. The substrate on which the transmitting interdigital transducer and the receiving interdigital transducer are formed and the substrate on which the balanced type surface acoustic wave filter is formed are located in a ceramic package.

Abstract: A balanced-type surface acoustic wave filter is provided which can attain a balanced-type of high frequency circuit without connecting a balance-unbalanced conversion circuit.A substrate of tantalic acid lithium substrate with 36 degrees rotation, Y cut, and X propagation is used, and aluminium is used for electrode to form resonators. Then, two resonators in a serial arm and two resonators in a parallel arm are connected in the form of symmetry and lattice to form a balanced-type surface acoustic wave filter. In this configuration, antiresonance frequency in the serial arms and resonance frequency in the parallel arms are substantially equal to each other.

Abstract: A compact, low height, low cost, and high reliability surface acoustic wave device, and its method of manufacture. The surface acoustic wave device consists of a substrate, a comb-electrode disposed on the main surface of the substrate, plural electrode pads disposed around the comb-electrode, protecting means covering the comb-electrode through a closed space produced by combining the comb-electrode and the electrode pads with the substrate by using substantially covalent bonding force acting between conductive bumps formed on the electrode bumps, a conductive adhesive layer disposed at least on the top of the conductive bumps, and a package adhered on the conductive bumps by means of the conductive adhesive, and insulation adhesive filled into the package contacting the conductive adhesive, the conductive bumps and the protective means.

Abstract: Integrated circuits utilizing piezoelectric elements can be advantageously constructed by bonding elements together via direct bonds. Such integrated circuits include an electro-acoustic hybrid integrated circuit such as a voltage controlled oscillator wherein a semiconductor substrate having an active element is bonded through direct bonding to a surface acoustic wave resonator or a quartz oscillator as an electro-acoustic element. A quartz device can also be provided which includes a quartz plate, excitation electrodes on opposite surfaces, and a holding member made of a material having a thermal expansion coefficient substantially equal to that of the quartz plate. The holding member is connected to the quartz plate by direct bonding without using any adhesives. Because the thermal expansion coefficients of the quartz plate and the holding member are equal, no thermal stress occurs in the bonding area.

Abstract: A resonator ladder surface acoustic wave (SAW) filter, which has a wide and flat pass band without spurious signals therein is provided. An input electrode, a serial arm SAW resonator, an output electrode, a parallel arm SAW resonator and a ground electrode are respectively formed on a 41.degree.-rotated Y-cut X-propagation lithium niobate substrate. The serial arm SAW resonator comprises a pair of interdigital transducers (IDTs) to excite SAW, one of which is connected to the input electrode. The output electrode is connected to the other IDT of the serial arm SAW resonator. The parallel arm SAW resonator comprises a pair of IDTs to excite SAW, one of which is connected to the output electrode. And the ground electrode is connected to the other IDT of the parallel arm SAW resonator. The IDTs are metal films of Al or Al-based alloy, and the thickness of the metal films ranges from 2.5% to 7.5% of the electrode cycle of the IDT of the parallel arm SAW resonator.

Abstract: The present invention provides surface acoustic wave devices which do not require a balanced-to-unbalanced transformer circuit regardless of the type of the peripheral circuits of the balanced type surface acoustic wave filter, i.e. a balanced type device or an unbalanced type. A transmitting interdigital transducer and a receiving interdigital transducer are formed on a substrate comprising 41.degree. Y cut-X propagation lithium niobate. A balanced type surface acoustic wave filter is formed on a substrate comprising 36.degree. Y cut-X propagation lithium tantalate. The balanced type surface acoustic wave filter comprises two series-arm surface acoustic wave resonators and two crossed-arm surface acoustic wave resonators connected in a lattice. The substrate on which the transmitting interdigital transducer and the receiving interdigital transducer are formed and the substrate on which the balanced type surface acoustic wave filter is formed are located in a ceramic package.

Abstract: A surface acoustic wave device including a dielectric substrate having an input electrode and an output electrode and a grounding electrode on a first surface of the dielectric substrate, and an outer electrode on a second surface of the dielectric substrate; and a surface acoustic wave element having an electrode pad and a comb-shaped electrode disposed on a first surface of the surface acoustic wave element. The surface acoustic wave element is bonded to the dielectric substrate via a metal bump and a conductive resin formed on the electrode pad. The surface acoustic wave device further includes an insulating resin deposited on the periphery of the metal bump, and a guard layer shorter in height than the surface acoustic wave element formed adjacent the surface acoustic wave element on the first surface of the dielectric substrate.

Abstract: Integrated circuits utilizing piezoelectric elements can be advantageously constructed by bonding elements together via direct bonds. Such integrated circuits include an electro-acoustic hybrid integrated circuit such as a voltage controlled oscillator wherein a semiconductor substrate having an active element is bonded through direct bonding to a surface acoustic wave resonator or a quartz oscillator as an electro-acoustic element. A quartz device can also be provided which includes a quartz plate, excitation electrodes on opposite surfaces, and a holding member made of a material having a thermal expansion coefficient substantially equal to that of the quartz plate. The holding member is connected to the quartz plate by direct bonding without using any adhesives. Because the thermal expansion coefficients of the quartz plate and the holding member are equal, no thermal stress occurs in the bonding area.

Abstract: A piezoelectric acoustic wave device includes a substrate and a piezoelectric plate. The piezoelectric plate includes a resonating part, and has a top electrode at least on the top surface of the resonating part. The substrate and the piezoelectric plate are directly bonded at an area where they are in contact with each other by a chemical bond such as a covalent bond and an ionic bond. A depression is formed in at least one of the substrate and the piezoelectric plate. The method of manufacturing the piezoelectric acoustic wave device includes the steps of forming a depression in at least one of the substrate and the piezoelectric plate, filling the depression with an intermediate support layer, cleaning the surfaces of the substrate and the piezoelectric plate to directly bond to each other by a chemical bond, forming electrodes, and removing the intermediate support layer.

Abstract: The following steps are performed when processing electronic components such as piezoelectric devices. At Step 1 inter-atom bond is created between a functional member such as a quartz crystal plate and a first substrate, and the functional member and the quartz crystal plate are directly joined together. At Step 2, the functional member and a second substrate are fixed together with an adhesive agent or by a direct bond. At Step 3, the first substrate is removed chemically or mechanically, with said functional member and said second substrate still being joined together. A step of polishing said functional member for the adjustment of thickness thereof may be done between Step 1 and Step 2. For example, a silicon dioxide thin film may be provided between the functional member and the first substrate. Since no adhesive layer exists between the functional member and the first substrate, this improves the degree of plane of the functional member when joined to the first substrate.

Abstract: A SAW filter is configured so that a resonator-type filter portion, in which a plurality of SAW resonators are connected in series and in parallel, and a 3-electrode type serially coupled filter portion, in which three IDTs for inputting and outputting signals are interposed between reflectors, are serially connected on one and the same substrate. The design parameters of the respective SAW resonators are adjusted so that the impedances of respective sides of the filter portions, when viewed from the node of the resonator-type SAW filter portion and the 3-electrode type serially coupled SAW filter portion, substantially have a complex conjugate relationship with each other in the pass frequency band.

Abstract: A surface acoustic wave filter having a configuration in which a plurality of series surface acoustic wave resonators and parallel surface acoustic wave resonators are connected is used as a receiving filter included in a receiving circuit of a communication apparatus capable of simultaneously transmitting and receiving signals. When the transmitting frequency is higher than the receiving frequency, one of the parallel surface acoustic wave resonator, connected between the signal line and the ground, is disposed most closely to the input terminal of the filter. When the transmitting frequency is lower than the receiving frequency, one of the series surface acoustic wave resonator, connected in series to the signal line, is disposed most closely to the input terminal of the filter. Accordingly, the singular point of the filter is prevented from coinciding with the transmitting frequency, so that the deterioration of the resonator is prevented.

Abstract: In a surface acoustic wave (SAW) filter, on a 36.degree. Y-cut X-propagation lithium tantalate substrate, series branch SAW resonators, which are connected in series between an input terminal and an output terminal, and parallel branch SAW resonators, which are connected between respective pairs of the series branch resonators by wirings and which are grounded, are provided. Two series branch resonators and one parallel branch resonator are connected in a T shape, so as to form a fundamental unit. In the SAW filter, three fundamental units are serially connected. An interdigital transducer (IDT) included in each resonator is made of a metal film containing aluminum as the main component. The thickness of the metal film is in the range of 8% to 10% of the electrode pitch of the IDT of the parallel branch resonator.