Display device

• US 20060262063A1
• Filed: 04/04/2006
• Published: 11/23/2006
• Est. Priority Date: 05/18/2005
• Status: Abandoned Application

• Current Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Takahashi, Hiroyuki
• Application Number:
  US11/396,639
• Publication Number:
  US 20060262063A1
• Time in Patent Office: Days
• US Class Current: 345/94
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors

Abstract

The present invention shortens time until an operation becomes stable when a frame inversion driving method is adopted as a common inversion driving method. In a display device which includes a plurality of pixels each of which includes a pixel electrode and a counter electrode which faces the pixel electrode in an opposed manner, and a drive circuit which drives the plurality of pixels, the drive circuit includes a common voltage generating circuit which supplies a common voltage to the counter electrodes, and the common voltage generating circuit changes over a voltage level of the common voltage with a first cycle in a non-display period, and changes over the voltage level of the common voltage with a second cycle which is longer than the first cycle in a display period.

Claims

1. A display device comprising a plurality of pixels each of which includes a pixel electrode and a counter electrode which faces the pixel electrode in an opposed manner, and a drive circuit which drives the plurality of pixels, wherein

the drive circuit includes a common voltage generating circuit which supplies a common voltage to the counter electrodes, and

the common voltage generating circuit changes over a voltage level of the common voltage with a first cycle in a non-display period, and changes over the voltage level of the common voltage with a second cycle which is longer than the first cycle in a display period.

2. A display device according to claim 1, wherein the common voltage generating circuit attenuates the voltage level of the common voltage with a first inclination during the non-display period and attenuates the voltage level of the common voltage with a second inclination which is smaller than the first inclination during the display period.

3. A display device according to claim 1, wherein the first cycle is a 1 horizontal scanning period cycle.

4. A display device according to claim 1, wherein the common voltage generating circuit does not perform the changeover of the voltage level of the common voltage during the display period in a 1 frame period.

5. A display device according to claim 1, the display device is a liquid crystal display device.

6. A display device comprising a plurality of pixels each of which includes a pixel electrode and a counter electrode which faces the pixel electrode in an opposed manner, and a drive circuit which drives the plurality of pixels, wherein

the drive circuit includes a common voltage generating circuit which supplies a common voltage to the counter electrodes,

the common voltage generating circuit includes a capacitive element having one terminal to which a first voltage is applied and another terminal which constitutes an output of the common voltage, and

a resistance element having one terminal which is connected to the another terminal of the capacitive element and another terminal to which a second voltage is applied,

the first voltage is a voltage whose voltage level is alternately changed from a first voltage level to a second voltage level having a potential lower than a potential of the first voltage level or from the second voltage level to the first voltage level,

a 1 frame period includes a first period and a second period which continuously follows the first period and is longer than the first period,

in the first period, a sum of the number of change of the first voltage from the first voltage level to the second voltage level and the number of change of the first voltage from the second voltage level to the first voltage level is twice or more, and

in the second period, the first voltage has the voltage level thereof held at either one of the first voltage level and the second voltage level.

7. A display device according to claim 6, wherein a resistance value of the resistance element in the second period in the 1 frame period is higher than a resistance value of the resistance element in the first period in the 1 frame period.

8. A display device according to claim 6, wherein the display device includes a switching element which is connected to the another terminal of the resistance element,

the resistance element is configured such that the second voltage is applied to the another terminal of the resistance element via the switching element, and

the switching element is turned on in the first period of the 1 frame period, and is turned off in the second period of the 1 frame period.

9. A display device according to claim 6, wherein the first period of the 1 frame period is a vertical blanking period.

10. A display device according to claim 6, wherein the first period of the 1 frame period is a non-display period, and the second period of the 1 frame period is a display period.

11. A display device according to claim 6, wherein in the first period of the 1 frame period, the first voltage has, in a 1 horizontal scanning period cycle, the voltage level thereof changed from the first voltage level to the second voltage level or from the second voltage level to the first voltage level.

12. A display device according to claim 6, wherein the display device is a liquid crystal display device.