| 摘要 |
<p>PROBLEM TO BE SOLVED: To judge the propriety of thin film transistors from the change of a current value by applying a standard voltage between each source and drain and between each gate and source of two thin film transistors, and then shifting one voltage in a current increasing direction. SOLUTION: Analog switches SW1A, SW2B are composed of an n-channel MOS transistor and a p-channel MOS transistor respectively. In the case of source-drain voltage Vds=1OV, for instance, source-drain current Ids is 1×10-8 A at gate-source voltage Vgs=OV, while in the p-channel MOS transistor with an off-leak failure, the current Ids is about 1×10-8 A at voltage Vgs=0V. With this difference, it is hard to discriminate a circuit insulation failure and a transistor failure from each other. Voltage Vds is therefore changed to 9V, or voltage Vqs is changed to -1V to compare the current Ids with the normal one. The current Ids thereby changes large to 1×10-6 to 1×10-4 A to specify the transistor failure.</p> |
