| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to carry out light quantity adjustment and lamp test irrespective of computer software when lighting of each LED is controlled by configuring the device so that a lamp test signal is impressed on each 2nd LED driver by impressing a light quantity adjusting signal on a switching element. SOLUTION: Since an electric power 5 is not supplied to LEDs 4 when a switching element 12 between the LEDs 4 and the electric power 5 is off, lamps are lighted off irrespective of any control from a computer 1. When the switching element 12 is driven on-off by a light quantity adjusting signal 10 of high cycle H/L values, it is possible to adjust a light quantity of the lighting LEDs 4 by varying a duty ratio of the H/L value. Moreover, it is possible to turn on all the LEDs 4 irrespective of any control from the computer 1 by turning on 2nd LED drivers 6 by making the lamp test input signal 11 to H, and thereby carry out lamp testing on each LED 4.
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