| 摘要 |
PURPOSE:To reduce the voltage applied to heat electrodes by preheating liquid crystal on the heat electrodes whose temperature is raised above initial temperature. CONSTITUTION:Switching elements S11, S21, S31, and S41 are switches for applying the voltage V1 of a heating power source 35 to heat electrodes 31, 32, 33, and 34, and switching elements S12, S22, S32, and S42 are switches for applying the voltage V2 of a preheating power source 36. When a heat electrode is heated, the switching element S12 is turned on firstly to apply the preheating voltage V2. At this time, the liquid crystal on the heat electrodes rise in temperature up to temperature T1. Then, the switching element S12 is turned off and the switching element S11 is turned on to apply the heating voltage V1, so that the temperature of the liquid crystal rises up to T2. This driving method allows driving by the preheating voltage V2 and heating voltage V1 which are lower than conventionl heating voltages. |
