Oki Electric Industry Co., Ltd.

Nihon Dempa Kogyo Co., Ltd.

Naoto Inose

Hok Huor Ou

Toshiaki Takeuchi

Crystal devices are disclosed, of which an exemplary device includes a crystal frame comprising a crystal vibrating piece having an electrode pattern and an outer frame supporting the crystal vibrating piece. The device also includes a crystal package base including at least one connection electrode formed on a first main surface and at least one external electrode formed on a second main surface, wherein the second main surface is opposite the first main surface. The crystal frame and crystal base are layered together with a lid wafer to form a 3-layer sandwich. The layers of the sandwich are bonded together by siloxane bonding, which results in the connection electrodes contacting the electrode pattern on the crystal vibrating piece.

Methods for manufacturing crystal devices

A SAW (Surface Acoustic Wave) filter includes serial arm resonators and parallel arm resonators interconnected in pairs in a multiple-stage, ladder configuration. A resonating device is serially connected to any one of the serial arm resonators and has an attenuation pole frequency higher than that of the serial arm resonator. At the attenuation pole frequency of the serial arm resonator, the resonating device functions as capacitance without performing attenuation. The resonating device has an antiresonance frequency 1.8 times or more but 2.2 times or less, or 2.7 times or more but 3.3 times or less, as high as the antiresonance frequency of the serial arm resonator.

SAW filter with an improved attenuation characteristic at a frequency any multiple of an attenuation pole frequency at one or both sides of a pass band

In a multiple stage ladder type SAW filter constructed by cascade-connecting several SAW resonators in the form of a multiple-stage ladder, the electrode pitches of the first stage series-arm SAW resonator through the last stage series-arm SAW resonator, respectively, are gradually decreased. In this case, each stage has a series-arm SAW resonator and a shunt-arm SAW resonator. As a result, the resonance frequencies of the first stage series-arm SAW resonator through the last stage series-arm SAW resonator are increased monotonically from the first stage to the last stage. As a consequence, the frequencies of the upper poles of attenuation generated by the series-arm SAW resonators differ from each other. Therefore, a desired amount of attenuation can be obtained over a wide band.

Multiple-stage ladder type SAW filter having series resonators with

A SAW filter has SAW resonators coupled in a ladder network with at least one .pi.-type section. Besides having a series-arm SAW resonator and two shunt-art SAW resonators, the .pi.-type section has an inter-stage matching SAW resonator coupled in series with the series-arm SAW resonator. The inter-stage matching SAW resonator has an interdigital transducer with an electrode finger pitch substantially equal to the pitch in the series-arm SAW resonator. The inter-stage matching SAW resonator reduces impedance mismatching between the left half and the right half of the .pi.-type section.

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Saitama, Japan

Naoto Inose