| 摘要 |
PROBLEM TO BE SOLVED: To provide a lamp switching device for video display which can switch over a lamp in use to a standby lamp nearly without any break of a displayed video signal if the lamp in use has deteriorated. SOLUTION: To a control circuit 41, the output signals of a 1st detector 51, a 2nd detector 52, and a switch 30 are inputted and when deterioration of the 1st lamp 11 is detected according to the output signal of the 1st detector 51, the 2nd lamp 12 is turned on in advance by a 2nd lamp power source 22, and a lamp moving mechanism makes the 2nd lamp 12 move to a specified projection position a certain time later and makes the switch 30 select the lamp illumination signal from the 2nd lamp power source 22. COPYRIGHT: (C)2003,JPO
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