| 摘要 |
PURPOSE:To discriminate the magnitude of an analogue input signal by the length and luminance of a bar graph, by stepwise changing the luminances of plural light emitting elements arranged unidimensionally corresponding to the magnitude of an input signal. CONSTITUTION:For example, in five-stage luminance distinction, max. luminance is set to 5 and four subsequent luminances are set to 4, 3, 2 and 1. Five pulses with a pulse width t0 are supplied to a light emitting diode D1 at time T0 and an average current corresponding to luminance 5 is supplied to the light emitting diode D. In the same way, the average current corresponding to the luminance 5 is respectively supplied to light emitting diodes D2, D3, D4 at times T1, T2, T3. At the next time T4, two pulses with a pulse width t0 are supplied to supply the average current corresponding to luminance 2 to a light emitting diode D5. By this method, a display device can be constituted of the reduced number of light emitting elements.
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