| 摘要 |
PURPOSE: To always apply a voltage close to an optimum counter voltage to a counter electrode as a counter voltage by applying the counter voltage to the counter electrode through a temp. compensation circuit. CONSTITUTION: When a temp. of a liquid crystal 21 is raised, inevitably, the temp. of a thin film transistor 6 formed on one side of the liquid crystal 21 is raised also in accordance with that. Then, the leakage current I of the thin film transistor 6 is increased, and when its current increment is defined as I1 -I0 , the output voltage VP of the temp. compensation circuit 5 is lowered byΔVP=RL.(I1 -I0 ). The RL is counter voltage control resistance. Further, initial operation point prescribed resistance R0 prescribes the variable amount of the voltage per a temp. variable mount, and then, it must be controlled precisely. Thus, though the temp. of the liquid crystal display device is raised, and the optimum counter voltage value is lowered, since the output of the temp. compensation circuit 5 is lowered also in accordance with that, the voltage close to the optimum counter voltage is applied to the counter electrode 23C as the counter voltage.
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