| 摘要 |
PROBLEM TO BE SOLVED: To provide a dust detector for a vacuum cleaner capable of surely detecting small dust without increasing the amplification degree of the output signals of a light receiving part for detecting the dust. SOLUTION: The dust detector for the vacuum cleaner comprises: a light emitting part 230 for emitting light into an air path 21 where the dust flows; a light receiving part 231 for receiving the light from the light emitting part 230 and outputting signals according to the received light quantity; a shielding means 2 for switching the light receiving area of the light receiving part 231; and a changeover detection means (not shown in the figure) for detecting the operation of the shielding means 2. For instance, when the shielding means 2 is switched and the light receiving area of the light receiving part 231 is reduced, the change of the received light quantity when the dust passes through relative to the reduced area of the light receiving part 231 becomes large when fine dust passes between the light emitting part 230 and the light receiving part 231, and the fine dust can be surely detected without increasing the amplification degree of the output signals of the light receiving part 231. COPYRIGHT: (C)2007,JPO&INPIT
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