| 摘要 |
PROBLEM TO BE SOLVED: To quickly determine a suspended particle amount without generating a delay, while adopting an inexpensive binary output type particle sensor. SOLUTION: A particle detector includes particle detecting means 3-7 for outputting an output in response to a photoreception quantity varied based on an influence of scattered light by a suspended particle in the air existing in an optical path, when receiving light emitted from a light emitting element by a photoreception element, a signal determination means 5 for determining the propriety of a high or low level by comparing the outputs from the particle detecting means 3-7 with a preset threshold value, a storage means 13 for storing determination results in the signal determination means 5 respectively in a prescribed detection time unit while delaying a time, a computing means 10 for computing sequentially an output time ratio of the high or low level, based on the determination results stored in the storage means 13 in the respective detection time units, and a particle amount determination means 10 for determining the suspended particle amount, based on the output time ratio computed by the computing means 10. COPYRIGHT: (C)2007,JPO&INPIT |
