OPTICAL TYPE SMOKE SENSING APPARATUS

摘要

PURPOSE:To make it possible to efficiently detect the existence of smoke, by such a simple constitution that a light blocking member for directly inhibiting light directing to a light receiving element from a light emitting element is provided to the intemediate position between both elements. CONSTITUTION:A transparent glass plate 7 is provided between a light source 3 and a light receiving element 4 while a light blocking plate 8 comprising a metal plate to which a black matte coating is applied is adhered to said glass plate 7 to block direct light directly incident to the light receiving element 4 among lights emitted from the light source 3. This light blocking plate 8 may be formed by a method for leaving only a light blocking part in a black color by photoetching technique or a method for coating or printing part with a black color on the glass plate. Therefore, smoke can be detected efficiently by such a simple constitution.