| 摘要 |
PURPOSE:To permit setting of an operating voltage to an optimum value by providing a monitor cell near a liquid crystal display panel and automatically determining a driving voltage value by a driving circuit to drive the display part by such voltage value. CONSTITUTION:A monitor cell 5 is provided near a display part for displaying figures, etc., and the driving circuit for the monitor cell is provided independently from the display part. The capacity of the monitor cell 5 is measured by said circuit. The driving voltage value at which the capacity ratio is max. is automatically determined from the capacity-voltage characteristic of the liquid crystal drawing a hysteresis loop and the display part is driven by such voltage value. More specifically, the determination of the voltage value to be impressed to maximize the capacity ratio by the automatic measurement of the capacity of the monitor cell 5 can be executed simply by measuring the capacity of the monitor cell with the monitor driving circuit independently provided from the driving circuit for making liquid crystal display, determining the voltage to maximize the capacity ratio and feeding back the same as the driving voltage of the liquid crystal display device.
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