| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-priced and highly sensitive dust sensor that fully unnecessary to align each of the optic axes of a floodlight and an optical receiver, that does not require great precision in material processing and assembling, and that stably obtains constant sensitivity in dust detection, not relying on a product. SOLUTION: A floodlight 2 illuminates the inside of pipe 1 for dust suction in a vacuum cleaner, while an optical receiver 3 detects brightness inside the pipe 1, which is illuminated with the floodlight 2. The floodlight 2 and the optical receiver 3 are arranged on an even part parallel to a central axis in the longitudinal direction of the pipe 1, as the floodlight 2 and the optical receiver 3 are separated a little and are parallel to each optic axis. As dust 10a, 10b pass through the pipe 1, a beam of light from the floodlight 2 is blocked off by the dust 10a and is reflected diffusely by the dust 10b. Because of this, the brightness of relevant part inside the pipe 1 relatively declines or rises, and an output value of the optical receiver 3 also decreases or increases. Therefore, the presence of dust is detected by detecting a change in the increase or decrease of this output value.
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