Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Kazuo Ikeda

Kazunori Nishimura

Tsutomu Igaki

Yasumichi Murase

Mitsuhiro Furukawa

Masahiro Takada

Shun-ichi Seki

Shunichi Seki

Ken Matsunami

Akio Tsunekawa

Kiyoharu Yamashita

A surface acoustic wave resonator has a piezoelectric substrate (), an IDT () formed of a plurality of electrode fingers () disposed on piezoelectric substrate (), and reflectors () disposed near the opposite ends of IDT (). The IDT () has a gradation region where the electrode finger pitch of the plurality of electrode fingers () at the opposite ends is different from the electrode finger pitch near the center of the IDT (). In this gradation region, the electrode finger pitches are sequentially varied in the range from the electrode finger at the farthest end that is one end of the gradation region to the electrode finger lying at the other end of the gradation region. The electrode finger pitch of the electrode fingers at the farthest end that is one end of the gradation region is set to be 1 through 5% smaller than the electrode finger pitch near the center of the IDT ().

Surface acoustic wave resonator, and surface acoustic wave filter

A Q-factor of a resonator at a high frequency is improved. An insertion loss of a filter using such a resonator and steepness of the filter are improved. A plurality of surface acoustic wave resonators including an interdigital transducer and reflecting electrodes provided on both sides thereof are connected in parallel on a piezoelectric substrate. Resonance frequencies of the surface acoustic wave resonators are rendered equal among all the resonators connected in parallel. In this way, the Q-factor of the resonance can be improved. A surface acoustic wave filter using such surface acoustic wave resonators is formed in order to improve the insertion loss and the steepness.

Surface acoustic wave resonator and surface acoustic wave filter using the same

A saw filter of the invention has a piezoelectric substrate (), plural numbers of IDT electrodes () arranged on a surface of the piezoelectric substrate () as well as on a first surface acoustic wave propagation path, reflector electrodes () arranged at least at both ends of a first electrode pattern formed including the plural IDT electrodes (), one or more IDT electrodes () arranged on the surface of the piezoelectric substrate () as well as on a second surface acoustic wave propagation path which is different from the first surface acoustic wave propagation path and reflector electrodes arranged at least at both sides of a second electrode pattern formed including the IDT electrode (), in which the IDT electrodes () on the first surface acoustic wave propagation path are electrically connected in series by connecting wirings () and the IDT electrode () on the second surface acoustic wave propagation path is connected between the connecting wirings () and the ground (), which are arranged between the first electrode pattern and the second electrode pattern. According to this, the chip size can be made small.

Surface acoustic wave filter

A surface acoustic wave (SAW) device includes a comb-shaped electrodea reflectorand a plurality of auxiliary electrodesandfor surrounding the comb-shaped electrodeand the reflectorwhich are electrically independent of each other and have different widths locally. The SAW device is capable of efficiently and electrically uniformizing electric charge generated by pyroelectric property of a piezoelectric substrate

Surface acoustic wave device, method of manufacturing the device, and electronic component using the device and method

A surface acoustic wave (SAW) device includes a piezoelectric substrate, and on this substrate there are provided comb electrodes for forming an inter digital transducer (IDT), reflector electrodes placed closely along a traveling direction of a surface wave generated by the IDT, and a frame-like short-circuited auxiliary electrode having a width varying depending on its portions. This structure allows to uniform electric charges overall the electrode-surfaces, where the electric charges are generated in a heat treatment applied to the piezoelectric substrate during the manufacturing of the SAW device. Thus even after the device is diced into pieces, this structure can prevent damages of the electrodes or degradation in electrical properties due to an electric discharge generated by accumulated electric charges caused by pyroelectricity of the substrate.

Surface acoustic wave device method of manufacturing the same, and electronic component using the same

A surface acoustic wave device comprises: a plurality of surface acoustic wave elements provided on a piezoelectric substrate to be electrically isolated with each other, a substrate provided with a first conductor electrically connecting the plurality of surface acoustic wave elements, a second conductor electrically isolated to the first conductor and an external terminal, and a sealing member for protecting the substrate and the piezoelectric substrate. For the substrate, a package having a recess or an insulating substrate is used. The first conductor is electrically isolated to the external terminal, while the second conductor is electrically connected with the external terminal. The above-described structure provides a small-sized surface acoustic wave device with excellent-attenuation characteristics.

Surface acoustic wave device having connection between elements made via a conductor not on the piezoelectric substrate

Provided is a method of manufacturing surface acoustic wave (SAW) devices having a first conductive pattern and a second conductive pattern of different thicknesses on one piezoelectric substrate. Combination of a plurality of steps of forming metal films and etching steps allows accurate production of SAW devices having a plurality of electrodes of different thicknesses on one piezoelectric substrate.

Growing community of inventors

Osaka, Japan

Kazuo Ikeda