| 摘要 |
PROBLEM TO BE SOLVED: To provide a disc detection technology enabling accurate detection even in a disc with the different transmittance of light.SOLUTION: A disc detector includes: a light emission intensity changing part 10 arranged in a position for receiving light from a light emission part 3 between the light emission part 3 and a traveling path of a disc D, connected to a light reception part 4 for detecting the light from the light emission part 3, and alternately performing increasing and decreasing of the light emission intensity of the light emission part 3 in a repetitive manner; and a disc determination part 30 for determining the presence/absence of the disc D in the traveling path according the presence/absence of the detection of the light by the light reception part 4, during the increasing or decreasing of the light emission intensity of the light emission part 3. |
