| 摘要 |
PROBLEM TO BE SOLVED: To provide the lighting system which prevents a white LED from damaging owing to a current flowing to the white LED above a permissible value and eliminates unnecessary power consumption by controlling the white LED to operate adaptively to its characteristics. SOLUTION: According to variation in the crest value of a driving signal detected by a voltage detection part 22, a control signal controller 23 controls the pulse width of a control signal turning on a transistor 2A and a liquid crystal display panel 1 can be always irradiated with illumination light of specific luminance from a back light 18; and variation in the temperature of the white LED 7 is detected by a sensor 20 and a temperature detecting meter 21 to save the electric power by preventing an overcurrent from flowing to the white LED 7 above standard temperature by shortening the pulse width of the control signal of the control signal controller 23 and suppressing a rise in the luminance below the standard temperature by shortening the pulse width of the control signal of the control signal controller 23. |
