| 摘要 |
PROBLEM TO BE SOLVED: To provide a lighting system for illuminating the required amount of light to a detection area of a line sensor, even when using a relatively small-sized light-emitting member. SOLUTION: This lighting system 4, equipped with LEDs 410 for illuminating light to a printed circuit board 2, causes the line sensor 5 to receive reflected light from the circuit board 2. The LEDs 410 are installed in a line form. In front of the LEDs 410, a condensing lens 42 for condensing light from the LEDs 410 and a diffraction grating 43 for diffracting the light condensed by the condensing lens 42 are installed on a linear area which is the detection area of the line sensor 5. The optical axes of the respective LEDs 410 are made to differ from each other by 20 deg to 30 deg so that minute polishing flaws formed on the circuit board 2 can be made to disappear. COPYRIGHT: (C)2005,JPO&NCIPI
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