| 摘要 |
PURPOSE:To properly actuate a liquid-crystal cell over a wide temperature range, by making plural driving voltages from a driving means equal to the optimum voltage in response to the intermittent change of one of plural auxiliary voltages to zero. CONSTITUTION:The optimum voltage which is determined by an optimum voltage determining means 6 decreases in accordance with the increase in the value of a temperature detecting signal from a temperature detecting means 5 in relation with characteristic data and the duty ratio of a duty signal from a duty signal generating means 7 decreases as the optimum voltage drops. The frequency of intermittent change to zero of one of plural auxiliary voltages from an auxiliary voltage producing means 3 is controlled by a control means so that the frequency can be reduced as the duty ratio decreases. Plural driving voltages from a driving means 4 drop as the frequency of the intermittent change of one of the plural auxiliary voltages decreases and, at the same time, become equal to the optimum voltage. Therefore, each driving voltage of a liquid-crystal cell 1 can always be maintained at the optimum voltage in characteristic data even if the temperature of the cell 1 fluctuates within a wide range.
|
