| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide the control method of a button illumination light circuit and a button illumination light circuit which prevents excessive voltage and current from flowing into a load, while a button can be illuminated uniformly. <P>SOLUTION: By once stopping a booster circuit just before changing lighting means 19-24 to be loaded and the constant current set point, excessive current does not flow since excessive voltage is not impressed to the load. Further, when light emitting diodes 19-24 are used for illumination, a surface can be adjusted to uniform brightness. As a result, at every place, the difference in the visibility by a place can be eliminated for fixed illuminance. This can be realized because it is made possible to pass a fixed current value which becomes independent from an individual load. In the density area wherein light emitting diodes 19-24 are crowded, a current value is lessened, while the current value is increased in a distributed area with few light emitting diodes 19-24. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
