Vaisala Oy

Instrumentarium Oy

Oy Beamex Ab

Markku Orpana

Ari Lehto

Martti Blomberg

Hannu Kattelus

Simo Tammela

Altti Torkkeli

Yrjo Koskinen

Eero Halonen

Aarne Utriainen

Anssi Korhonen

Overpressure protector

A single-channel gas concentration measurement method and apparatus. According to the method, a radiant source is employed to generate a measuring signal, the measuring signal is subsequently directed to a measurement object containing a gas mixture to be measured, the measuring signal is subsequently bandpass filtered using at least two passband wavelengths, and the filtered measuring signals are detected by a detector. According to the invention, the bandpass filtering step is implemented by a single electrostatically tunable, short-resonator Fabry-Perot interferometer.

Single-channel gas concentration measurement method and apparatus using

An electrically modulatable radiant source includes an essentially planar substrate, a well or hole formed in the substrate, and at least one incandescent filament attached to the substrate. The incandescent filament is aligned with the well or hole and is formed of a metallic compound which readily oxidizes at an operating temperature of the incandescent filament. An oxidation resistant film encapsulates the incandescent filament to prevent the filament from oxidizing. Furthermore, contact pads are formed on the substrate at both ends of the incandescent filament for feeding electric current to the incandescent filament.

Thermal radiant source with filament encapsulated in protective film

An electrostatically tunable Fabry-Perot interferometer produced by surface micromechanical techniques is used in optical material analysis as an optical sweeping filter in which the optical measurement wavelength is centered at a wavelength .lambda.. The Fabry-Perot interferometer based sensor structure comprises a body block, two essentially parallel mirrors bonded to the body block, of which mirrors at least one is partially transmitting and movable relative to the body block. The mirrors are spaced maximally by a few half-wavelengths, .lambda./2, from each other, and both of the mirror structures include integral electrode structures capable of effecting an electrostatic force between the mirror structures. The movable mirror structure is provided with structurally weakened regions surrounding the optical area of the mirror so as to facilitate keeping the optical area at a maximum degree of flatness. At least one of the electrode structures surrounds the optical area so as to achieve a mechanical lever action and avoid galvanic contact between the electrode of the movable mirror structure and the electrode of the fixed mirror structure.

Electrically tunable fabry-perot interferometer produced by surface

A radiant source including an essentially planar substrate having a well or hole formed therein. At least one incandescent filament is mounted to the substrate and aligned at the well or hole. Contact pads are formed onto the substrate, to both ends of the incandescent filament, and feed electric current to the incandescent filament. Furthermore, each incandescent filament is doped with phosphorus to an impurity concentration of at least 5.times.10.sup.19 atoms/cm.sup.3.

Electrically modulatable thermal radiant source and method for

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Espoo, Finland

Markku Orpana