Fuji Electric Co., Ltd.

Kabushiki Kaisha Riken

Satoru Sakaue

Masahiro Uno

Mutsumi Nagumo

Michihiko Tsuruoka

Masami Kishiro

Hironobu Yao

Wataru Nakagawa

Tetsuo Uchiyama

Noritomo Hirayama

Takeshi Suzuki

Kenichi Tsuji

Wan Jiang

Yosheyuki Sekine

Masao Sakanaka

An acceleration sensor can ensure rigidity of its movable electrode despite a large number of through-holes formed in the movable electrode. The acceleration sensor has an SOI substrate in which a silicon oxide layer is formed on a silicon support layer and an active silicon layer is formed on the silicon oxide layer, wherein the active silicon layer of the SOI substrate has a movable electrode supported by elastic beams and configured with a weight, and also has fixed electrodes disposed in a fixed manner around the movable electrode to face the movable electrode, and wherein through-holes penetrating in a Z-axis direction are formed over the entire surface on the inner side of an outer circumference to which the elastic beams of the movable electrode are connected.

Acceleration sensor

An infrared gas analyzer is formed of a source of infrared rays for emitting infrared flux; an infrared flux interrupting device for chopping the emitted infrared flux from the source of the infrared rays; a condensing optical system for obtaining a predetermined solid angle in the emitted infrared flux to thereby form a condensed flux; and a multi-reflection cell disposed at an outlet of the condensing optical system, to which the condensed flux is supplied and a gas to be measured is fed. The multi-reflection cell has a multi-reflection optical system formed of a plurality of concave mirrors. The analyzer also includes an infrared level detector for detecting an amount of infrared rays with a wavelength band absorbed by a component gas to be analyzed and contained in the infrared rays emitted by the multi-reflection cell. At least the condensing optical system, multi-reflection cell and infrared level detector are accurately positioned by using as a reference a position of the condensing optical system at which the condensed flux is emitted, and are coupled tightly at coupling positions without an air-flowing layer. Accordingly, the infrared gas analyzer can be made small to detect and analyze a low density component gas and for an explosion-proof environment.

Infrared gas analyzer

In an infrared radiation source containing hot-pressed molybdenum disilicide reinforced with silicon carbide whiskers as the illuminant thereof, terminal portions of the illuminant having a protective dense silica film of 5 to 20 .mu.m in thickness formed on the surface thereof which portions are to be heated at a temperature of 400 to 800.degree. C. are either set to have a current density of at most 12 A/mm.sup.2 or disposed in dry air having a relative humidity at 25.degree. C. of at most 30% (absolute humidity: 0.00588). As a result, the low-temperature oxidation phenomenon that would otherwise be developed in the terminal portions of the illuminant is suppressed. Thus, there can be obtained an infrared radiation source containing an illuminant made of molybdenum disilicide reinforced with silicon carbide whiskers and having a long serviceable life span.

Molybdenum disilicide ceramic composite infrared radiation source or

A ceramic heating element has been conventionally driven by direct-current voltage, but the direct-current voltage causes a problem in the heating element. Therefore, in a method of the present invention, an alternating current is supplied to the heating element by changing a direct current, so that deformation of the heating element can be prevented and reliability can be improved.

Driving method of ceramic heating element for an infrared ray source

A pneumatic infrared gas detector includes a pair of expansion chambers and a pair of pressure chambers, each of which is connected at one end thereof to the corresponding expansion chamber. Each of the pressure chambers is divided by a diaphragm into a first chamber connected to a corresponding expansion chamber, and a second chamber, such that the first chamber of one of the pair of pressure chambers is connected to the second chamber of the other of the pressure chambers through a first communication path, and such that the second chamber of the above-indicated one of the pressure chambers is connected to the first chamber of the other of the pressure chambers through a second communication path. A pair of pneumatic pressure detecting elements are provided each of which includes an electret film having one surface on which an electrode is formed, and an electrode plate disposed in opposed relationship with the electret film. The electret film is formed on a first side of a corresponding one of the diaphragms in each pressure chamber, and the electrode plate is supported and fixed at a position that is opposed to a second side of the corresponding diaphragm.

Pneumatic infrared gas detector

A second torsional vibrator having an outer frame and a second torsional spring is formed on the outer side of a first torsional vibrator having a pair of torsional springs and a plate member (reflection mirror), with a second torsional vibrator being fixed by the fixed part. The resonant frequency for the first torsional vibrator is set higher than that for the second torsional vibrator. The outer frame in the second torsional vibrator is driven substantially at the resonant frequency of the first torsional vibrator by an electromagnetic or electrostatic force. As a result, it becomes possible to obtain a stable and large scanning angle by using only a small driving force.

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Tokyo, Japan

Satoru Sakaue