Liquid crystal display device, method of controlling the same, and mobile terminal
View Patent ↗A liquid crystal display device enabling a reduction in size and costs associated with the system as a whole, starting to display images without image distortion at power on time, and turning the screen off without image retention at power off time, a method of controlling the liquid crystal display device, and a mobile terminal incorporating the liquid crystal display device as a screen display. On a glass substrate ( 11 ) provided with a display unit ( 12 ), peripheral drive circuits such as an interface circuit ( 13 ), a timing generator ( 14 ), a reference voltage driver ( 15 ), a CS driver ( 18 ), a VCOM driver ( 19 ), and a voltage regulation circuit ( 20 ), together with a horizontal driver ( 16 ) and a vertical driver ( 17 ) are disposed. When a display reset control pulse PCI is supplied from an external source, a predetermined voltage is written into pixels while a CS voltage and a VCOM voltage adjusted to the same level as that of a pixel voltage are applied to a common-electrode-side. This allows the screen to turn white in a normally white type liquid crystal display, and to turn black in a normally black type liquid crystal display. Image distortion at power on/off time can thus be prevented.
1. A liquid crystal display device, comprising:
a display unit wherein pixels are arranged in a matrix on a transparent insulating substrate; and
wherein a voltage-generating means is mounted together with the display unit on the transparent insulating substrate and applying a common voltage to a common-electrode-side of all the pixels at a time other than power on/of time, and alternatively applying a voltage having the same level as that of a predetermined voltage, instead of the common voltage to the common-electrode-side of all the pixels at power on/off time.
2. A liquid crystal display device according to claim 1 , wherein a switching means selects an output voltage of the voltage-generating means at power on/off time.
3. A liquid crystal display device according to claim 2 , wherein the output voltage of the voltage-generating means is a voltage applied to the common electrodes of liquid crystal cells in the pixels, or a voltage applied to electrodes of storage capacitors via CS lines.
4. A liquid crystal display device according to claim 1 , wherein a switching means selects an output voltage of the voltage-generating means at power on/off time; and
wherein the output voltage of the voltage-generating means is a voltage applied to the common electrodes of liquid crystal cells in the pixels, or a voltage applied to the common electrodes of storage capacitors of the pixels via a CS line.
5. At the liquid crystal display of claim 1 , wherein the liquid crystal display is embodied within a mobile terminal.
6. A method of controlling a liquid crystal display device, comprising both a display unit having pixels arranged in a matrix and voltage-generating means applying a common voltage to a common-electrode-side of all the pixels comprising:
writing a predetermined voltage into each pixel of the display unit for a certain period of time while the voltage-generating means applies a voltage having a same level as that of the predetermined voltage to the common-electrode-side of all the pixels;
wherein the voltage-generating means is disposed on the same transparent insulating substrate as the pixel matrix of the display unit.
7. A method of controlling a liquid crystal display device as in claim 6 further comprising:
at a power off time, writing a predetermined voltage into each pixel of the display unit for a certain period of time while the voltage-generating means applies a voltage having the same level as that of the predetermined voltage to the common-electrode-side of all the pixels;
wherein the voltage-generating means is disposed on a same transparent insulating substrate as the pixel matrix of the display unit, and
turning the power off.
8. A mobile terminal incorporating a liquid crystal display device as a screen display, comprising:
a display unit wherein pixels are arranged in a matrix on a transparent insulating substrate; and
wherein a voltage-generating means is mounted together with the display unit on the transparent insulating substrate and applying a common voltage to the common-electrode-side of all the pixels at a time other than power on/of time, but applying a voltage having the same level as that of a predetermined voltage, instead of the common voltage to the common-electrode-side of all the pixels at power on/off time.
9. A mobile terminal according to claim 8 having a standby mode, wherein a switching means apply the predetermined voltage to each pixel of the display unit while the voltage-generating means apply a voltage having the same level as that of the predetermined voltage to the common-electrode-side of the pixels, when entering/exiting the standby mode.
10. A method of controlling a liquid crystal display device comprising;
a display unit having pixels arranged in a matrix and voltage-generating means applying a common voltage to the common-electrode-side of all the pixels and after the liquid crystal display device has been powered on, at a power off time,
writing a predetermined voltage into each pixel of the display unit for a certain period of time while the voltage-generating means applies a voltage having the same level as that of the predetermined voltage to the common-electrode-side of all the pixels; and
turning the power off;
wherein the voltage-generating means is disposed on a same transparent insulating substrate as the pixel matrix of the display unit.