Nittan Company Limited

Ryuichi Yamazaki

Takashi Suzuki

Kazuyoshi Sakurai

Yuki Yoshikawa

Seiji Tsubouchi

Yasuhiro Sugano

Fire detector

A smoke sensor includes a light receiving unit for temporally alternately receiving scattered light of two different wavelengths .lambda..sub.1 and .lambda..sub.2 ; a calculating unit for performing a calculation required for smoke detection, on a scattered light output y of the wavelength .lambda..sub.1 and a scattered light output g of the wavelength .lambda..sub.2 from the light receiving unit; and a smoke detection processing unit for performing a smoke detection process on the basis of a calculation result output from the calculating unit. The calculating unit estimates an output value of one of the scattered light output y of the wavelength .lambda..sub.1 and the scattered light output g of the wavelength .lambda..sub.2 at a sample timing of the other output, and obtains a ratio of the estimated output value of the one scattered light at the sample timing of the other output to an output value of the other scattered light, as a two-wavelength ratio.

Growing community of inventors

Tokyo, Japan

Ryuichi Yamazaki