Optical liquid detecting method

Abstract

Abstract PURPOSE:To evade the influence of disturbing light and to identify liquid with high accuracy by turning on and off plural light sources. CONSTITUTION:Light emitting elements 21 and 22 and a light receiving element 30 are arranged on the opposite internal surface 1b of a transparent medium 1 from its detection surface 1a. Their projection light beams 101 and 102 are guided in the medium 1 at mutually different angles by a prism 4 adhered optically to the internal surface 1b of the medium 1. Incident light which is propagated in the medium 1 by total reflection is guided out of the medium 1 through a prism 5 adhered optically to the internal surface 1b similarly and transduced into an electric signal by the light receiving element 30. The light sources 21 and 22 are turned on and off with two opposite-phase pulses and the output of the element 30 appears as the sum of two reflected light and disturbing light. This output is processed as an AC signal to eliminate a DC component (disturbing light component), and the liquid can be identified with high accuracy.

Inventors

• 👤 Masataka Ito
• 👤 政隆 伊藤
• 👤 Takashi Sugihara
• 👤 孝志 杉原
• 👤 Masanori Watanabe
• 👤 昌規 渡辺
• 👤 Shuhei Tsuchimoto
• 👤 修平 土本
• 👤 Masaya Hijikigawa
• 👤 枡川　正也

Bibliographic Details