| 摘要 |
<p>A photoacoustic gas sensor comprising a cavity (10) having a gas flow port (20) for introducing the open air and an infrared ray introducing window (30), a gas diffusion filter (40) consisting of a porous silicon layer disposed in the gas flow port integrally with the cavity, a microphone (50) forming a portion of the inner wall surface of the cavity and provided with a first electrode (51) in wave form to detect the sound pressure in the cavity, and a light source (60) for pulse-radiating infrared rays to the interior of the cavity through an infrared ray introducing window, characterized in that particularly the inner wall surface of the cavity, except its gas flow port and infrared ray introducing window, is coated with an infrared ray reflecting film (70) of Au, Al or the like. And a photoacoustic gas sensor simple in construction and small in size is realized that increases the efficiency of infrared ray absorption by the detection subject gas in the cavity irradiated with infrared rays of limited intensity and increases the gas detection sensitivity.</p> |
