| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a projection image display device which is capable of reducing the load of an AC power source without stopping image projection when detecting the reduction of a supply voltage during display operation. <P>SOLUTION: A comparator 9 compares a divided voltage VD1 with a reference voltage VR1 to output a "H" (high-level) or "L" (low-level) comparator output voltage V9. The comparator output voltage V9 is converted to a control microcomputer input voltage V1 through a photo coupler PC 1 and is inputted to a control microcomputer CPU 1. The control microcomputer CPU 1 monitors the control microcomputer input voltage V1 being a pulse signal to measure a time T when pulses of the control microcomputer input voltage V1 stop, and outputs power-saving command signals C21 and C22 to lamp power sources 21 and 22 in the case of excess of the time T over a preliminarily determined reference value TR. The lamp power sources 21 and 22 perform various power-saving processing on lamps 31 and 32 on the basis of the power-saving command signals C21 and C22. <P>COPYRIGHT: (C)2012,JPO&INPIT |
