US 9,959,828 B2Granted

Method and apparatus for driving display panels during display-off periods

AssigneeSolomon Systech Limited

InventorsCheung Fai Lee, Jun Chen, Hongyi Qian

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Abstract

A method for driving a thin film transistor (TFT) liquid crystal display (LCD) panel during a display-off period is provided for avoiding image flickering when the panel resumes image display. Flickering when resuming image display is due to charge accumulated on liquid crystals (LCs) during the display-off period. For a cell having a TFT and a LC, the method releases the accumulated charge by driving a gate electrode with a VGH voltage to turn on the TFT for a short pre-determined duration regularly over the display-off period. Over the pre-determined duration, a VCOM electrode and a source electrode of the cell are also driven with a GND voltage, thereby releasing the accumulated charge from the LC as the TFT is turned on. The remaining time in the display-off period may be advantageously used for touch sensing while avoiding flickering after image display is resumed.

Claims20

Dependent claims

A method for driving a thin film transistor (TFT) liquid crystal display (LCD) panel during a display-off period, the panel comprising plural cells, each of the cells having a TFT for driving a liquid crystal (LC), a gate electrode coupled to a gate of the TFT, a source electrode coupled to one end of the LC via the TFT, and a VCOM electrode coupled to another end of the LC, the method comprising the steps of:

(a) when the display-off period begins, driving the gate electrode, the source electrode and the VCOM electrode to configure the panel to be black for a first pre-determined duration unless such configuring of the panel is prematurely terminated by a termination of the display-off period;
(b) when the first pre-determined duration expires, driving the gate electrode with a VGH voltage to turn on the TFT for a second pre-determined duration;
(c) over the second pre-determined duration within which the gate electrode is driven with the VGH voltage in the step (b), driving the source electrode and the VCOM electrode with the GND voltage, whereby charge accumulated on the LC is released;
(d) when the second pre-determined duration expires, driving the gate electrode, the source electrode and the VCOM electrode to configure the panel to be black again for the first pre-determined duration unless such configuring of the panel is prematurely terminated by the termination of the display-off period;
and
(e) repeating the steps (b), (c) and (d) until the display-off period expires or the termination of the display-off period occurs.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/253,730Filed 31 Aug 2016
Published: US 2018/0061338 A11 Mar 2018
Granted: 1 May 2018
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G09G 3/3648
Control of matrices with row and column drivers: using an active matrix
G09G 3/3614
Control of matrices with row and column drivers: control of polarity reversal in general
G09G 3/3655
Using an active matrix: details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
G09G 2300/0426
Structural details of the set of electrodes: layout of electrodes and connections