Sanyo Electric Co., Ltd.

Other

Toshiharu Tanaka

Kenichi Shibata

Kousuke Takeuchi

Yasumi Kobayashi

Yasuhiro Hirao

Kuniyuki Matsui

Kazuhiko Kuroki

Yusuke Takahashi

Hiroshi Kayaki

Isao Kiyose

Hiroshi Okano

Masakazu Sakata

Toshiaki Yokoo

Masayuki Fujita

Maruo Kamino

Yukinori Kuwano

Masami Ikeda

Yasutaka Shimizu

Shoichi Nakano

Masaru Yamano

Kosuke Takeuchi

Toshikazu Tsujino

Seiji Nishikawa

The invention provides a three-stage surface acoustic wave filter of the ladder type wherein the resonance frequency difference &Dgr;f between the resonance frequency f of a serial resonator in an intermediate stage and the resonance frequency f of a parallel resonator therein is set at a value greater than the resonance frequency difference &Dgr;f (&Dgr;f ) between the resonance frequency f (f ) of a serial resonator in each of front and rear stages and the resonance frequency f (f ) of a parallel resonator therein, whereby the filter is given a widened pass band while reliably retaining satisfactory characteristics comparable to those of conventional surface acoustic wave filters of small pass band width. The desired filter exhibiting such performance is available within a shorter period of time and with reduced labor.

Surface acoustic wave filter

A surface acoustic wave filter according to the present invention is constructed by connecting in series one or two or more filter functional units each comprising a first surface acoustic wave resonator having input and output terminals connected in series with a signal line and a second surface acoustic wave resonator having input and output terminals one of which is connected to the signal line and the other of which is grounded. The first surface acoustic wave resonator is constituted by one interdigital transducer and a pair of electrically open strip type grating reflectors with the interdigital transducer interposed therebetween, and the second surface acoustic wave resonator is constituted by one interdigital transducer and a pair of electrically short strip type grating reflectors with the interdigital transducer interposed therebetween.

Surface acoustic wave filter including series and parallel interdigital

In a resonator-type surface acoustic wave filter comprising a lithium tantalate substrate, lithium niobate substrate or lithium tetraborate substrate having a cut plane of high velocity, the direction of propagation of surface acoustic waves is set within the range of (40 deg to 90 deg, 40 deg to 90 deg, 0 deg to 60 deg) as expressed in Eulerian angles, and the frequency difference .increment.f between the resonance frequency frs of series resonators and the resonance frequency frp of parallel resonators is set within a predetermined range formulated with the center frequency, the capacitance Cos of the series resonators and the capacitance Cop of the parallel resonators taken as parameters. Optimum ranges of the required design parameters are thus clarified to assure the resonator-type surface acoustic wave filter of higher performance.

Surface acoustic wave filter with range of a frequency difference

Surface accoustic wave filter

Surface acoustic wave filter including alternate open and shorted

Antiskid apparatus comprising a first doglegged linkage of two rods which are pivotally connected together on one end and a second doglegged linkage of two rods which are pivotally connected together on one end, the linkages being pivotally connected in the middle of the respective rods to form a pantograph. A circular support member is pivotally mounted on the open end of each of the rods, and a thin-plate-shaped gripping member is fixed to each of the support members. Each of the gripping members comprises a ground contact portion that contacts the tire tread and covers at least a part of the width of the tread and a mounting portion that contacts the tire sidewall. In one embodiment, the linkage is held in a specified form by means of a holder, and the apparatus is mounted on the tire by securing hooks of tighteners in positions corresponding to the tire wheel holes, the hooks being provided at the top of the tighteners.

Antiskid apparatus having doglegged linkages pivotally connected

A surface acoustic wave device comprising a single crystal silicon substrate and a piezoelectric thin film of single crystal or C-axis-oriented polycrystalline aluminum nitride formed on the surface of the substrate. The C-axis of the piezoelectric thin film is set in a direction in which the projection vector of the C-axis on a plane containing the axis of propagation direction of a surface acoustic wave and a normal axis of the substrate makes an inclination angle .theta. of up to 60 degrees with the axis of propagation direction, whereby the device is given a coupling coefficient of at least 2% is given as maximum coupling coefficient of the device.

Surface acoustic wave device

A liquid crystal chopper comprising a pair of electrically conductive substrates, a spacer keeping the substrates so as to define a space between the substrates, and a liquid crystal of DSM type which is enclosed in the space, with a dielectric anisotropy of -0.5 or more and not exceeding 0. An infrared sensor using the liquid crystal chopper in the above construction as a chopper mechanism to intermittently interrupt infrared rays incident upon the pyroelectric element. The infrared sensor has a short response time at the liquid crystal chopper and consumes less power.

Liquid crystal chopper and infrared sensor

An infrared gas analyzer using a pyroelectric infrared sensor, which includes a heating unit for heating the infrared sensor, a heating sensor for detecting its heating temperature and a temperature sensor for detecting the ambient temperature of the infrared sensor, and controls the heating unit so as to retain the ambient temperature of the infrared sensor at a constant so that the output error is small irrespective of the change in ambient temperature.

Heated infrared gas analyzer using a pyroelectric infrared sensor

A surface acoustic wave device having a single crystal aluminum nitride film wherein when the direction of propagation of the surface acoustic wave is expressed by (.lambda.,.mu.,.theta.) according to the Euler angle notation, .theta. is set to 90 degrees, .lambda. to a desired angle, and .theta. to an angle in the range of 30 to 150 degrees. In a surface acoustic wave device having a c-axis-oriented aluminum nitride film, the direction of c-axis orientation of the piezoelectric film is inclined within a plane containing the direction of propagation of the surface acoustic wave and perpendicular to the surface of the piezoelectric film at an angle in the range of about .+-.30 degrees to about .+-.150 degrees with respect to a normal to the piezoelectric film. The devices are 1.122% in maximum coupling coefficient.

In an apparatus wherein an infrared sensor is incorporated opposite to an opening formed at a predetermined position of a housing, a distance keeping member for keeping a constant distance from a temperature measuring portion is further mounted on another predetermined position of the housing, and an output signal from the infrared sensor responding to the infrared rays from the temperature measuring portion is supplied to a temperature measuring circuit whose operational state is selected by a temperature measurement control switch, and the temperature of the temperature measuring portion is displayed on a display unit which is driven by the output signal from the temperature measuring circuit.

Growing community of inventors

Higashiosaka, Japan

Toshiharu Tanaka