Liquid crystal display device

• US 6,396,468 B2
• Filed: 09/09/1998
• Issued: 05/28/2002
• Est. Priority Date: 09/26/1997
• Status: Expired due to Fees

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Matsushima, Yasuhiro, Etoh, Sunao
• Primary Examiner(s): Shalwala, Bipin
• Assistant Examiner(s): Kovalick, Vincent E.
• Application Number:
  US09/150,028
• Publication Number:
  US 20010013852A1
• Time in Patent Office: 1,357 Days
• Field of Search: 345/87,92,100,103,208,209 348/792 349/37
• US Class Current: 345/87
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2310/0205 Simultaneous scanning of several lines in flat panels
• CPC Class Codes: G09G 2310/021 Double addressing, i.e. scanning two or more lines, e.g. lines 2 and 3; 4 and 5, at a time in a first field, followed by scanning two or more lines in another combination, e.g. lines 1 and 2; 3 and 4, in a second field
• 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 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 3/3674 Details of drivers for scan electrodes
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

A liquid crystal display device includes a liquid crystal between a substrate having gate buslines, source buslines, switching elements, pixel electrode array, gate driver, source driver, etc., and a substrate having a counter electrode, etc. In this liquid crystal display device, the gate driver performs simultaneous two-line scanning by applying a scanning signal to two gate buslines simultaneously. The source driver feeds video signals of opposite polarities to adjacent source buslines, respectively. The video signals are inverted every vertical scanning period.

Claims

1. A liquid crystal display device comprising:

a first substrate having gate buslines, source buslines, switching elements which are arranged in the vicinity of intersections of said gate buslines and source buslines so as to form a matrix pattern, and a pixel electrode array formed by pixel electrodes connected to said switching elements;

a gate driver and a source driver, for driving said switching elements;

a second substrate having a counter electrode formed thereon; and

a liquid crystal material sandwiched between said first and second substrates,

wherein said gate driver applies scanning signals simultaneously to two gate buslines located adjacent to each other,

said source driver applies video signals of opposite polarities to adjacent source buslines, respectively, and inverts the polarities of the video signals every vertical scanning period,

the polarity of the video signals applied to the source buslines remains the same during one vertical scanning period, and

said switching elements connected to said source buslines are positioned alternately on one side and the other side of said source buslines.

2. The liquid crystal display device as set forth in claim 1, further comprising

a plurality of video signal lines for feeding the video signals,

wherein the polarities of the video signals to be input to said video signal lines are inverted every vertical scanning period.

3. The liquid crystal display device as set forth in claim 2,

wherein the polarities of the video signals to be applied to the pixel electrodes of adjacent columns of said pixel array are arranged to be opposite to each other.

4. The liquid crystal display device as set forth in claim 2,

wherein said gate driver includes a multiplexer for contributing to generation of scanning signals which scan said gate buslines sequentially two gate buslines at a time.

5. The liquid crystal display device as set forth in claim 4,

wherein said multiplexer includes four control terminals.

6. The liquid crystal display device as set forth in claim 1,

wherein the polarities of the video signals to be applied to the pixel electrodes of adjacent columns of said pixel array are opposite to each other.

7. The liquid crystal display device as set forth in claim 6,

wherein said gate driver includes a multiplexer for contributing to generation of scanning signals which scan said gate buslines sequentially two gate buslines at a time.

8. The liquid crystal display device as set forth in claim 7,

wherein said multiplexer includes four control terminals.

9. The liquid crystal display device as set forth in claim 1,

wherein said gate driver is formed on said first substrate.

10. The liquid crystal display device as set forth in claim 1,

wherein said gate driver includes a multiplexer for contributing to generation of scanning signals which scan said gate buslines sequentially two gate buslines at a time.

11. The liquid crystal display device as set forth in claim 10,

wherein said gate driver comprises:

a shift register; and

a logical gate circuit, disposed between said shift register and said multiplexer, for reducing the number of signals to be input to said multiplexer to a half.

12. The liquid crystal display device as set forth in claim 10,

wherein said multiplexer includes four control terminals.

13. The liquid crystal display device comprising:

a first substrate having gate buslines, source buslines, switching elements which are arranged in the vicinity of intersections of said gate buslines and source buslines so as to form a matrix pattern, and a pixel electrode array formed by pixel electrodes connected to said switching elements;

a gate driver and a source driver, for driving said switching elements;

a second substrate having a counter electrode formed thereon; and

a liquid crystal material sandwiched between said first and second substrates,

wherein said gate driver applies scanning signals simultaneously to two gate buslines located adjacent to each other,

said source driver applies video signals of opposite polarities to adjacent source buslines, respectively, and inverts the polarities of the video signals every vertical scanning period, and

said switching elements connected to said source buslines are positioned alternately on one side and the other side of said source buslines.

14. The liquid crystal display device as set forth in claim 13,

wherein said gate driver includes a multiplexer for contributing to generation of scanning signals which scan said gate buslines sequentially to gate buslines at a time.

15. The liquid crystal display device as set forth in claim 14,

wherein said multiplexer includes four control terminals.

16. A liquid crystal display device comprising:

a first substrate having gate buslines, source buslines, switching elements which are arranged in the vicinity of intersections of said gate buslines and source buslines so as to form a matrix pattern, and a pixel electrode array formed by pixel electrodes connected to said switching elements;

a gate driver and a source driver, for driving said switching elements;

a second substrate having a counter electrode formed thereon; and

a liquid crystal material sandwiched between said first and second substrates,

wherein said gate driver applies scanning signals simultaneously to two gate buslines located adjacent to each other,

said source driver applies video signals of opposite polarities to adjacent source buslines, respectively, and inverts the polarities of the video signals every vertical scanning period, and

wherein said gate driver comprises;

a shift register including m/4 scanning circuits and one extra scanning circuit, m being the number of said gate buslines,

a first logical circuit including m/4 output terminals corresponding to said m/4 scanning circuits, and outputs an ON signal from an output terminal corresponding to one scanning circuit when both of the output of said one scanning circuit and an output of a scanning circuit adjacent to said one scanning circuit are ON signals; and

a second logical circuit formed by m/4 multiplexers,

phases of the outputs from said scanning circuits of said shift register are shifted by an amount of a half of a pulse width of the ON signal, and

first to fourth control signals having a cycle equal to the pulse width of the ON signal output from said first logical circuit are input to said multiplexers, respectively, the first and second control signals having an equal phase, the third and fourth control signals having a phase shifted by ½

cycle from the phase of the first and second control signals.

17. A liquid crystal display device comprising:

a first substrate having gate buslines, source buslines, switching elements which are arranged in the vicinity of intersections of said gate buslines and source buslines so as to form a matrix pattern, and a pixel electrode array formed by pixel electrodes connected to said switching elements;

a gate driver and a source driver, for driving said switching elements;

a second substrate having a counter electrode formed thereon; and

a liquid crystal material sandwiched between said first and second substrates,

wherein said gate driver applies scanning signals simultaneously to two gate buslines located adjacent to each other,

said source driver includes video signal lines of two kinds having polarities that are opposite to each other and that are inverted every vertical scanning period, each of the two kinds of said video signal lines including at least one video signal line,

one source busline of an arbitrary pair of two adjacent source buslines is connected with a video signal line of one kind, and the other source busline of said pair is connected with a video signal line of the other kind, so that video signals of opposite polarities are applied to said source buslines of said pair, respectively, and

said switching elements connected to said source buslines are positioned alternately on one side and the other side of said source buslines.

18. The liquid crystal display device as set forth in claim 17,

wherein the polarities of the video signals to be applied to the pixel electrodes of adjacent columns of said pixel array are opposite to each other.

19. The liquid crystal display device as set forth in claim 18,

wherein said gate driver includes a multiplexer for contributing to generation of scanning signals which scan said gate buslines sequentially two gate buslines at a time.

20. The liquid crystal display device as set forth in claim 19 wherein said multiplexer includes four control terminals.

21. The liquid crystal display device as set forth in claim 17,

wherein said gate driver is formed on said first substrate.

22. The liquid crystal display device as set forth in claim 17,

wherein said gate driver includes a multiplexer for contributing to generation of scanning signals which scan said gate buslines sequentially two gate buslines at a time.

23. The liquid crystal display device as set forth in claim 22,

wherein said gate driver comprises:

a shift register; and

a logical gate circuit, disposed between said shift register and said multiplexer, for reducing the number of signals to be input to said multiplexer by half.

24. The liquid crystal display device as set forth in claim 22, wherein said multiplexer includes four control terminals.

25. A liquid crystal display device comprising:

a first substrate having gate buslines, source buslines, switching elements which are arranged in the vicinity of intersections of said gate buslines and source buslines so as to form a matrix pattern, and a pixel electrode array formed by pixel electrodes connected to said switching elements;

a gate driver and a source driver, for driving said switching elements;

a second substrate having a counter electrode formed thereon; and

a liquid crystal material sandwiched between said first and second substrates,

wherein said gate driver applies scanning signals simultaneously to two gate buslines located adjacent to each other,

said source driver includes video signal lines of two kinds having polarities that are opposite to each other and that are inverted every vertical scanning period, each of the two kinds of said video signal lines including at least one video signal line,

one source busline of an arbitrary pair of two adjacent source buslines is connected with a video signal line of one kind, and the other source busline of said pair is connected with a video signal line of the other kind, so that video signals of opposite polarities are applied to said source buslines of said pair, respectively, and

wherein said gate driver comprises;

a shift register including m/4 scanning circuits and one extra scanning circuit, m being the number of said gate buslines,

a first logical circuit including m/4 output terminals corresponding to said m/4 scanning circuits, and outputs an ON signal from an output terminal corresponding to one scanning circuit when both of the output of said one scanning circuit and an output of a scanning adjacent to said one scanning circuit are ON signals; and

a second logical circuit formed by m/4 multiplexers,

phases of the outputs from said scanning circuits of said shift register are shifted by an amount of a half of a pulse width of the ON signal, and

first to fourth control signals having a cycle equal to the pulse width of the ON signal output from said first logical circuit are input to said multiplexers, respectively, the first and second control signal having an equal phase, the third and fourth control signals having a phase shifted by one-half cycle from the phase of the first and second control signals.

26. A liquid crystal display device comprising:

a pair of spaced apart substrates with a liquid crystal layer interposed therebetween;

a matrix of parallel gate buslines and parallel source buslines arranged on one of said substrates;

pixel electrodes connected to said gate buslines and said source buslines; and

a gate driver and a source driver for driving said gate buslines and said source buslines; and

a video signal line pair to which video signals of opposite polarity are applied, wherein

each of said source buslines is connected to one of said video signal lines via a switch,

first alternate ones of said source buslines are connected to a first one of the video signal line pair and second alternate ones of said source buslines are connected to a second one of the video signal line pair,

said gate driver drives said gate buslines by applying scanning signals simultaneously to two adjacent ones of said gate buslines,

said source driver drives said source buslines by applying video signals of opposite polarities to adjacent source buslines and by reversing the polarity of the video signals applied to each of the source buslines every vertical scanning period, and

said source driver comprises a shift register and the on/off control of said switches is based on outputs of said shift register.

27. A liquid crystal display device comprising:

a pair of spaced apart substrates with a liquid crystal layer interposed therebetween;

a matrix of parallel gate buslines and parallel source buslines arranged on one of said substrates;

pixel electrodes connected to said gate buslines and said source buslines; and

a gate driver and a source driver for driving said gate buslines and said source buslines;

wherein

said gate driver drives said gate buslines by applying scanning signals simultaneously to two adjacent ones of said gate buslines,

said source driver drives said source buslines by applying video signals of opposite polarities to adjacent source buslines and by reversing the polarity of the video signals applied to each of the source buslines every vertical scanning period, and

each source busline is alternately connected to pixel electrodes on opposite sides thereof.

28. A liquid crystal display device comprising:

a pair of spaced apart substrates with a liquid crystal layer interposed therebetween;

a matrix of parallel gate buslines and parallel source buslines arranged on one of said substrates;

pixel electrodes connected to said gate buslines and said source buslines; and

a gate driver and a source driver for driving said gate buslines and said source buslines;

wherein

said gate driver drives said gate buslines by applying scanning signals simultaneously to two adjacent ones of said gate buslines,

said source driver drives said source buslines by applying video signals of opposite polarities to adjacent source buslines and by reversing the polarity of the video signals applied to each of the source buslines every vertical scanning period, and

said gate driver comprises;

scanning circuits;

first logic circuits each logically combining outputs of two of said scanning circuits; and

second logic circuits each logically combining an output of one of said first logic circuits and a control signal and outputting a scanning signal to a respectively corresponding one of said source buslines in accordance with the logical combination.

29. The liquid crystal display device as set forth in claim 28, wherein

the output of each first logic circuit is provided to more than one second logic circuit.