| 摘要 |
PURPOSE:To regulate a light emitting amount with the number of components of a minimum limit by providing bias voltage varying means for actively varying a bias voltage to be applied at each LED driving means. CONSTITUTION:Since bias voltage varying means 11 for actively varying a bias voltage to be applied at each LED driving means (6a-6n) is provided, i.e., a diode 11 is connected as the bias voltage varying means between a power source and the emitter terminal of a transistor 5, current amounts to be fed to LEDs 9a-9n can be limited, thereby reducing the light emitting amounts of the LEDs 9a-9n smaller than those of LEDs 8a-8n. Thus, the light emitting amounts of the LEDs can be regulated with the number of components of a minimum limit. |
