| 摘要 |
PURPOSE:To cause LEDs of each chip to emit light in a substantially fixed quantity of light, by a system wherein independent lead wires are connected to common-side electrodes of each chip, a pulse of voltage is impressed, and the pulse width of the pulse of voltage is controlled substantially in inverse proportion to the light emission luminance of the LED of a corresponding chip. CONSTITUTION:Pulse width data substantially inversely proportional to the light emission luminances of the LEDs 2a of the chips 21-2n are stored in a ROM 11 in one-to-one correspondence with the chips 21-2n. With a counting action of a counter 12 started, pulses of voltage are outputted to AND gates 81-8n, and each time the counter 12 counts a predetermined clock, the pulses of voltage outputted to the AND gates 81-8n are caused to fall on the basis of the pulse width data stored. The pulses of voltage are impressed on COM1-COMn on a time division basis, and a time pulse voltage substantially inversely proportional to the light emission luminance of the LED 2a of each chip is impressed on the common-side electrode of each of the chips 21-2n. Accordingly, the LEDs 2a of the chips 21-2n emit light in a substantially fixed quantity of light. |
