Patent ID: 8760651
Filing Date: 2014-06-24
Classification: G08B

Abstract:
1. A smoke detector, comprising: a light emitting section; a light receiving section; and a smoke detecting section, the light receiving section receiving, via a light transmissive member, scattered light generated when light emitted from the light emitting section is scattered in the smoke detecting section due to particles of smoke or contaminants; the smoke detector further comprising: a test light source provided for detecting light receiving sensitivity of the light receiving section, and wherein reduction in the light receiving sensitivity of the light receiving section is detected through detection of an increase in received light intensity of test light, which is emitted from the test light source and is received by the light receiving section, wherein the light receiving section receives scattered light generated when the test light, which is emitted from the test light source and enters the light transmissive member, is scattered in a case where an abnormality caused by contamination, cracks or the entrance of insects occurs in the light transmissive member, and wherein reductions in the light receiving sensitivity of the light receiving section are detected when the received light intensity increases more than the light intensity received under normal conditions without any abnormality caused by receiving scattered light.