| 摘要 |
PURPOSE:To automatically detect trouble to display it in a short period of time by writing test data and detecting the change of the output current of an LED driving power source of a display device and comparing it with a prescribed current change and displaying the result. CONSTITUTION:When a CPU 21 generates test data '1' and writes it n a display device 1, the driving current flows from a power source device 5 to anode drivers 12 and cathode drivers 13 to light all bits of LEDs (light emitting diodes) 14. Since the driving current of LEDs 14 at this time is considerably increased in comparison with that for non-lighting, this current change is detected by a current detector 6 and is read into a controller as a signal, and it is discriminated whether the change is larger than a certain value or not, and normalcy is displayed on a monitor 24 when it is larger tan the certain value, but abnormality is displayed there when it is not larger. Next, data '0' is generated and is written in the display device 1, and it is discriminated whether the output is normal or not and the result is displayed in the same manner. Thus, the presence or the absence of trouble of the display device 1 is automatically detected and displayed in a short period of time.
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