Image display device with plural data driving circuits for driving the display at different voltage magnitudes and polarity

• US 5,748,165 A
• Filed: 12/23/1994
• Issued: 05/05/1998
• Est. Priority Date: 12/24/1993
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.), the united states of america as represented by the secretary of the navy
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kubota, Yasushi, Katoh, Kenichi, Yoneda, Hiroshi
• Primary Examiner(s): Powell, Mark R.
• Application Number:
  US08/363,017
• Time in Patent Office: 1,229 Days
• Field of Search: 358/103, 358/89, 358/90, 358/92, 345/95-96, 345/103, 345/206, 345/208, 345/211, 345/127, 345/100, 345/109
• US Class Current: 345/96
• CPC Class Codes: G09G 2310/0224 Details of interlacing
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• 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 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/3614 Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
• CPC Class Codes: G09G 3/3659 the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

In order to sufficiently save the power consumption and to lower the withstand voltage of elements, by having one data signal line per one row of pixels and one scanning signal line per one line of pixels, the polarity of data written in the data signal line is varied each one field period. The power source magnitude of the scanning signal lines to be written is further varied each one field period. Specifically, on opposing sides of the pixel array, data signal line driving circuits are provided. The data signal line driving circuits supply voltages of different magnitude and polarity. Adjoining pairs of data signal lines are connected to each of the data signal line driving circuits with analog switches. In a certain display period, such as every field period, the analog switches each select one of a pair of adjacent data signal lines. In the next display period, the reverse selection is made. This suppresses the charge and discharge current of the data signal lines, and thus the operating voltages of the data signal line driving circuits may be lowered. As a result, the power consumption of the image display device may be saved, and the withstand voltage of the constituent elements can be lowered. Thus, manufacturing cost and operating cost can be reduced.

Claims

1. An image display device comprising:

a plurality of pixels disposed in a matrix form;

a plurality of scanning signal lines, each scanning signal line connected to one row of the pixels;

a plurality of data signal lines, each data signal line connected to one column of the pixels;

a scanning signal line driving circuit for driving each scanning signal line with a scanning signal;

a plurality of data signal line driving circuits, each individually powered by a power source of a different voltage magnitude, for applying input video signals of a first polarity to a first group of the data signal lines and applying video signals of a second polarity, different from the first polarity, to a second group of data signal lines, and inverting the polarity of the video signals applied to the first and second groups of the data signal lines in every predetermined data display period; and

means for switching a connection combination of the plurality of data signal line driving circuits between the first group and the second group of the data signal lines every predetermined data display period by switching connection of terminals of the plurality of data signal line driving circuits between data signal lines belonging to one of the first and second groups and data signal lines belonging to another of the first and second groups every predetermined data display period.

2. The image display device of claim 1, wherein the means for switching includes two systems of switching elements, each of the switching elements in each system being commonly connected to one output stage of one of the data signal line driving circuits, and connected to a pair of data signal lines, and each of the two systems of switching elements being conducted alternately in every predetermined data display period to different ones of each data signal line pair.

3. The image display device of claim 1, wherein the means for switching includes a first switching element connected to one output stage of the data signal line driving circuits for receiving an input video signal, and a second switching element for applying the received video signal to the data signal lines.

4. The image display device of claim 1, wherein part or all of the data signal line driving circuits and means for switching are formed on one of a monocrystalline silicon thin film and a polycrystalline silicon thin film formed on an insulating substrate.

5. The image display device of claim 2 or 3, wherein the switching elements or the first switching element and second switching element are gates of a CMOS structure including a parallel connected n-channel transistor and p-channel transistor.

8. The image display device of claim 1 or 6, wherein the data signal line driving circuits are driven at such a supply voltage as to each apply only the video signal of one polarity to a data signal line.

9. The image display device of claim 1 or 6, wherein the data signal line driving circuits include,

sampling means for sampling the video signals and for transferring the sampled video signals to the data signal lines.

10. The image display device of claim 1 or 6, wherein the data signal line driving circuits include,

sampling means for sampling the video signals,

holding means for temporarily holding the video signals sampled by the sampling means, and

amplifying means for amplifying the video signals held by the holding means and for transferring the amplified video signal to the data signal lines.

11. The image display device of claim 1 or 6, wherein the data signal line driving circuits include,

sampling means for sampling digital signals representing video information,and

selecting means for selecting one of a plurality of discrete voltages based upon the digital signals sampled by the sampling means and for transferring the selected discrete voltages to the data signal lines.

12. The image display device of claim 1 or 6, wherein the data signal line driving circuits are disposed on the same side of the pixel matrix.

13. The image display device of claim 1 or 6, wherein each pixel possesses a liquid crystal element.

20. The image display device of claim 1, wherein the means for switching switches the plurality of data signal line driving circuits every field of input video signals.

21. The image display device of claim 1, wherein the first group includes odd-numbered data signal lines and the second group includes even-numbered data signal lines.

6. An image display device comprising:

a plurality of pixels disposed in a matrix form;

a plurality of scanning signal lines, each scanning signal line connected to one row of the pixels;

a plurality of data signal lines, each data signal line connected to one column of the pixels;

a scanning signal line driving circuit for driving each scanning signal line with a scanning signal;

a plurality of data signal line driving circuits for applying input video signals of a first polarity to a first group of the data signal lines and applying video signals of a second polarity to a second group of the data signal lines, and inverting the polarity of the video signals applied to the first and second groups of the data signal lines in every predetermined data display period; and

connecting means for connecting each of the plurality of data signal line driving circuits to power sources of different voltage magnitudes and polarities, the connecting means connecting each of the plurality of data signal line driving circuits to power sources of different magnitudes and polarities every predetermined data display period,

wherein, part or all of the data signal line driving circuits are formed on one of a monocrystalline silicon thin film and a polycrystalline silicon thin film formed on an insulating substrate.

7. The image display device of claim 6, wherein the connecting means is formned on the insulating substrate.

22. The image display device of claim 6, wherein the first group includes odd-numbered data signal lines and the second group includes even-numbered data signal lines.

23. The image display device of claim 6, wherein the connecting means connects each of the plurality of data signal line power sources of different magnitudes to each of the plurality of data signal line driving circuits every field of input video signals.

14. A display driving system for driving an image display device including a plurality of scanning lines arranged in parallel in a first direction, a plurality of data lines arranged in parallel in a second direction perpendicular to the first direction so as to intersect the plurality of scanning lines, and a matrix of picture elements arranged at the data and scanning line intersections, the display driving system, comprising:

scan line driving means for supplying scan line drive signals to the plurality of scanning lines;

first data line driving means for applying input data signals and signals of a first magnitude and first polarity to the data lines;

second data line driving means for applying input data signals and signals of a second magnitude and second polarity, different from each of the first magnitude and first polarity respectively, to the data lines; and

switching means for switching a connection combination of the first and second data line drive means between a first group of the data lines and a second group of the data lines, different from the first group, every predetermined display period by switching connection of terminals of the first and second data line drive means between the data signal lines belonging to one of the first and second groups and data signal lines belonging to another one of the first and second groups every predetermined display period.

15. The display driving system of claim 14, wherein the first group of data lines include odd-numbered data lines and the second group includes even-numbered data lines.

16. The display driving system of claim 14, wherein the switching means includes a first switching circuit connected between the first data line driving means and a first end of the data lines and a second switching circuit connected between the second data line drive means and a second end of the data lines, opposite the first end.

17. The display driving system of claim 16, wherein each of the first and second switching circuits include a plurality of switches, each for connecting one of the first and second data line driving means to one of a pair of data lines.

18. The display driving system of claim 14, wherein the switching means switches connection between the first and second data line driving means and the first and second group of data lines every field of the input data signals.

19. The display driving system of claim 17, wherein the switching means switches connection between the first and second data line driving means and the first and second group of data lines every field of the input data signals.