| 摘要 |
<p>PURPOSE: To obtain a back light controller capable of making the luminance of a back light uniform in a wide AC voltage range of plural rated power sources, etc. CONSTITUTION: This back light controller has an impedance circuit which is composed of capacitors 7 and 10 connected in series and a triac 11 connected in parallel with this capacitor 10 and is capable of changing impedance by turning on this triac by a triac on signal 13, diodes 8a to 8d which rectify the output of this impedance circuit, the back light 2 which emits light by the back light currents regulated by these diodes 8a to 8d and a voltage detecting means 12 which detects AC voltage and feeds the triac on signal 13 for changing the impedance to the impedance circuit according to the detection contents thereof.</p> |
