Liquid crystal display device, method for controlling the same, and portable terminal
AssigneeSony Corporation
InventorsNoboru Toyozawa, Yoshiharu Nakajima, Yoshihiko Toyoshima
Life of this patent
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Abstract
An active-matrix liquid crystal display device has pixels arranged in a matrix which each include a thin film transistor (TFT) as an active element. When the device is in a power-off state, TFTs in all the pixels are switched on, and all horizontal switches are turned on so that all data lines are supplied with a potential equal to the potential of common electrodes of the pixels. This forms a discharging path for discharging residual charge in all the pixels, and the discharging path can instantaneously discharge the residual charges.
Claims10
A liquid crystal display device comprising:
- a pixel section having pixels arranged in a matrix which include active elements, and signal lines connected to columns of pixels;
- first control means for switching on the active elements for all the pixels in said pixel section when said liquid crystal display device is in a power-off state;
- and
- second control means for setting, in the power-off state, all the signal lines to each have a potential equal to the potential of common electrodes of the pixels.
A liquid crystal display device comprising:
- a pixel section having pixels arranged in a matrix which include active elements, and signal lines connected to columns of pixels;
- and
- selecting means for selecting one of a first power-off mode and a second power-off mode in accordance with the type of power-off state of said liquid crystal display device, wherein:
- in the first power-off mode, in the power-off state, white level signals or black level signals are written in all the pixels while the pixels in said pixel section are first selected in a sequential manner in units of rows;
- and
- in the second power-off mode, in the power-off state, the active elements for all the pixels in said pixel section are switched on and all the signal lines are set to each have a potential equal to the potential of common electrodes of the pixels.
A method for controlling a liquid crystal display device having pixels arranged in a matrix which include active elements, and signal lines connected to columns of pixels, said method comprising the steps of:
- switching on the active elements for all the pixels;
- and
- setting all the signal lines to each have a potential equal to the potential of common electrodes of the pixels.
A method for controlling a liquid crystal display device having pixels arranged in a matrix which include active elements, signal lines connected to columns of pixels, a power-off button, and a power-supply battery, said method comprising the steps of:
- for a power-off state caused by operating the power-off button, writing white level signals or black level signal to all the pixels while first selecting the pixels in a sequential manner;
- and
- for a power-off state caused by removing the power-supply battery, switching on the active elements for all the pixels, and setting all the signal lines to each have a potential equal to the potential of common electrodes of the pixels.
A portable terminal comprising a liquid crystal display device used as a screen display unit, said liquid crystal display device comprising:
- a pixel section having pixels arranged in a matrix which include active elements, and signal lines connected to columns of pixels;
- first control means for switching on the active elements for all the pixels in a power-off state;
- and
- second control means for setting, in the power-off state, all the signal lines to each have a potential equal to the potential of common electrodes of the pixels.
A portable terminal comprising a liquid crystal display device used as a screen display unit, said liquid crystal display device comprising:
- a pixel section having pixels arranged in a matrix which include active elements, and signal lines connected to columns of pixels;
- and
- selecting means for selecting one of a first power-off mode and a second power-off mode in accordance with the type of power-off state,
- wherein:
- in the first power-off mode, in the power-off state, white level signals or black level signals are written in all the pixels while the pixels in said pixel section are first selected in a sequential manner in units of rows;
- and
- in the second power-off mode, in the power-off state, the active elements for all the pixels in said pixel section are switched on and all the signal lines are set to each have a potential equal to the potential of common electrodes of the pixels.
Dependencies are inferred from the claim text.