Liquid crystal display device
View Patent ↗A liquid crystal display device is composed of a liquid crystal display panel which includes liquid crystal pixels arranged in a matrix form and each having liquid crystal held between a pixel electrode and a common electrode, scanning lines arranged along the rows of pixels, signal lines arranged along the columns of pixels and pixel switching elements arranged near intersections between the scanning lines and the signal lines and each driven via a corresponding scanning line, and a display control circuit which controls the display panel. The display control circuit is configured to simultaneously drive all of the scanning lines, transition the potentials of the signal lines to a value substantially equal to potential of the common electrode in a state where the scanning lines are driven within a one-frame period, and turn off a power source after a preset period of time required for the transition has elapsed.
1. A liquid crystal display device comprising:
a display control circuit comprising:
a signal driver which drives a plurality of liquid crystal pixels arranged in substantially a matrix form, each of the liquid crystal pixels having liquid crystal held between a pixel electrode and a common electrode;
a scan driver which drives a plurality of scanning lines arranged along the rows of liquid crystal pixels;
a power supply circuit which outputs a logic-system power source voltage and an analog-system power source voltage; and
a controller which controls the signal driver, the scan driver, and the power supply circuit; and
a liquid crystal display panel which includes:
a plurality of signal lines arranged along the columns of liquid crystal pixels; and
a plurality of pixel switching elements arranged near intersections between the scanning lines and the signal lines, each of the pixel switching elements being driven via a corresponding scanning line to set the potential of a corresponding signal line to the pixel electrode of a corresponding liquid crystal pixel,
wherein the controller is configured to:
control the scan driver to drive all of the scanning lines to simultaneously turn on the pixel switching elements during a transition time of within 10 ms in response to off-operation of a power source switch,
provide a discharge path for the pixel electrode,
control the power supply circuit first to set the analog-system power source voltage to zero after the transition time has elapsed and then set the logic-system power source voltage to zero, and
turn off a power source.
2. The liquid crystal display device according to claim 1 , wherein:
the power supply circuit further includes a gate-on power source which generates a gate-on voltage for urging the pixel switching elements to be conductive, and a gate-off power source which generates a gate-off voltage for urging the pixel switching elements to be non-conductive, and
the controller controls the power supply circuit, in response to the off-operation of the power source switch, to set the off-voltage of the gate-off power source to zero within the transition time, and then set on-voltage of the gate-on power source, the analog-system power source voltage of the analog-system power source, and the logic-system power source voltage of the logic-system power source to zero in this order.
3. The liquid crystal display device according to claim 1 , wherein the display control circuit has electrostatic protection resistors connected between the common electrode and the signal lines in the liquid crystal display panel.