ELECTROOPTICAL DEVICE AND ELECTRONIC APPARATUS

• US 20120056917A1
• Filed: 08/26/2011
• Published: 03/08/2012
• Est. Priority Date: 09/03/2010
• Status: Active Grant

• Current Assignee: 138 East LCD Advancements Limited (Vector Capital Corporation)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: ITO, Akihiko
• Granted Patent: US 9,460,680 B2
• Time in Patent Office: Days
• US Class Current: 345/691
• CPC Class Codes: G09G 2310/0218 with collection of electrodes in groups for n-dimensional addressing
• CPC Class Codes: G09G 2310/0248 Precharge or discharge of column electrodes before or after applying exact column voltages
• CPC Class Codes: G09G 2310/0275 Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

A scanning line driving circuit sequentially selects each of a plurality of scanning lines for each unit period. A signal supply circuit supplies, to a signal line, a gradation potential in accordance with a designated gradation of a pixel in a write period within the unit period. The signal supply circuit supplies a pre-charge potential to the signal line in a pre-charge period before the start of the write period in a first unit period of the plurality of unit periods, and the supply of the pre-charge potential to the signal line stops in a second unit period.

Claims

1. An electrooptical device, comprising:

a plurality of pixels that is arranged so as to correspond to each intersection of a plurality of scanning lines and a plurality of signal lines, and displays a gradation corresponding to a potential of the signal line at the time of selection of the scanning line;

a scanning line driving circuit that sequentially selects the plurality of scanning lines for each of a plurality of unit periods; and

a signal supply circuit that supplies, to each of the plurality of signal lines, a gradation potential corresponding to a designated gradation of each of the plurality of pixels in a write period of the unit period, supplies a pre-charge potential to each of the plurality of signal lines before the start of the write period in a first unit period of the plurality of unit periods, and stops the supply of the pre-charge potential corresponding to each of the plurality of signal lines in a second unit period which is different from the first unit period.

2. The electrooptical device according to claim 1, wherein the first unit period and the second unit period are set to the same time length, and the write period of the first unit period and the write period of the second unit period are set to the same time length.

3. The electrooptical device according to claim 1, wherein the first unit period and the second unit period are set to the same time length, and a time length of the write period of the second unit period is longer than a time length of the write period of the first unit period.

4. The electrooptical device according to claim 1, wherein the write period of the first unit period and the write period of the second unit period are set to the same time length, and a time length of the second unit period is shorter than a time length of the first unit period.

5. The electrooptical device according to claim 1, wherein the scanning line driving circuit sequentially selects each of the plurality of scanning lines for each of the plurality of unit periods in a plurality of vertical scanning periods, and each of the plurality of vertical scanning periods includes the first unit period and the second unit period.

6. The electrooptical device according to claim 5, wherein each of the plurality of unit periods corresponding to the odd number lines is set to one of the first unit period and the second unit period, and each of the plurality of unit periods corresponding to the even number lines is set to the other of the first unit period and the second unit period.

7. The electrooptical device according to claim 5, wherein each of the plurality of unit periods is set to one of the first unit period and the second unit period in each of a plurality of first vertical scanning periods, and is set to the other of the first unit period and the second unit period in each of a plurality of second vertical scanning periods which is different from the plurality of first vertical scanning periods.

8. The electrooptical device according to claim 1, wherein the signal supply circuit includes

a signal generation circuit that supplies, to a control line, a control signal which is set to a pre-charge potential in a pre-charge period before the start of the write period of each of the plurality of first unit periods while being set to the gradation potential corresponding to the designated gradation of each of the plurality of pixels in a time division manner in the write period of each of the unit periods,

a plurality of switches that controls the connection between each of the plurality of signal lines and the control line, and

a control circuit that controls all of the plurality of switches in an on state in the pre-charge period of the plurality of first unit periods, and sequentially controls each of the plurality of switches in an on state in the write period of each of the plurality of unit periods.

9. An electronic apparatus including the electrooptical device of claim 1.