| 摘要 |
PURPOSE:To make the device small-sized, simple and inexpensive by the con struction wherein a lighting-extinguishing control element is composed of a digital circuit and an integrating circuit and the input of the integrating circuit is connected to the output of the digital circuit in a driving device which turns on and off a light-emitting diode. CONSTITUTION:A waveform R1 of the output of an OR circuit 3 causes an output in each of sections b, c, d and e on the time axis, and a waveform G1 of the output of an OR circuit 4 causes an output likewise in each of sections d, e, f and g thereon. These outputs have either of two values ON and OFF. These outputs in digital amounts are transmitted to integrating circuits 5 and 6 respectively, and thereby the waveform R1 is processed, in the leading edge portion Rh1 and the trailing edge portion Rd1 thereof, into a waveform R2 having a gradually-increasing leading edge portion Rh2 and a gradually- decreasing trailing edge portion Rd2, by a time constant of the integrating circuit 5 set appropriately, while the waveform G1 is processed likewise into a waveform G2 by the aforesaid integrating circuit 6. By this method, a digital output is formed to contain an intermediate value between ON and OFF operations, and thereby the object of mixing colors smoothly is achieved. |
