Liquid crystal display device, active matrix type liquid crystal display device, and method of driving the same

• US 6,496,172 B1
• Filed: 03/26/1999
• Issued: 12/17/2002
• Est. Priority Date: 03/27/1998
• Status: Expired due to Term

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Hirakata, Yoshiharu
• Primary Examiner(s): Saras, Steven
• Assistant Examiner(s): Anyaso, Uchendu O.
• Application Number:
  US09/276,757
• Time in Patent Office: 1,362 Days
• Field of Search: 348/793, 345/94, 345/98, 345/87, 345/90, 345/96, 345/100, 349/42, 359/13
• US Class Current: 345/96
• CPC Class Codes: G09G 2310/0213 controlling the sequence of the scanning lines with respect to the patterns to be displayed, e.g. to save power
• 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 2320/0247 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 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

A liquid crystal display device with no flicker and with bright excellent display is provided. A polarity pattern of a conventional frame inversion driving is one kind of display. A polarity pattern of a conventional source line inversion driving is two kinds of display, and a disclination pattern is one kind of display. On the contrary, in a circuit structure of the present invention, polarity patterns are made to have not less than four kinds, and disclination patterns are made to have not less than two kinds. By this, bright display in which flicker is not included and poor display due to disclination is improved, can be obtained.

Claims

1. A liquid crystal display device comprising a liquid crystal panel, the liquid crystal panel including:

a pair of substrates; and

a liquid crystal sealed between the substrates,

one of the substrates being provided with N scanning lines, M signal lines, and M×

N display pixels respectively disposed at each of crossing portions between the scanning lines and the signal lines, and an image signal having a positive or negative polarity being applied to each of the display pixels so as to make image display;

wherein image signals having a same polarity are applied for every n (M>

n≧

2) adjacent lines of the signal lines; and

wherein a boundary portion between a group of the display pixels connected to the n signal lines applied with the image signals having the positive polarity and a group of the display pixels connected to the n signal lines applied with the image signals having the negative polarity is periodically moved.

2. A device according to claim 1, wherein the boundary portion is moved every frame or field interval.

3. A device according to claim 1, wherein the liquid crystal panel includes at least two image signal wiring lines, and the image signal wiring lines include a first image signal wiring line applied with the image signal having the positive polarity, and a second image signal wiring line applied with the image signal having the negative polarity.

4. A device according to claim 1,

wherein the liquid crystal panel includes a switching element at each of the crossing portions between the scanning lines and the signal lines, and

wherein the scanning lines, the signal lines, and the switching element are formed on the same substrate.

5. A device according to claim 1,

wherein the liquid crystal panel includes a polarity selecting circuit for selecting the polarity of the image signal applied to the signal lines, and

wherein the signal lines, the scanning lines, a switching element, and the polarity selecting circuit are formed on the same substrate.

15. A video camera having the liquid crystal display device of claim 1.

16. An electronic still camera having the liquid crystal display device of claim 1.

17. A projector having the liquid crystal display device of claim 1.

18. A head mount display having the liquid crystal display device of claim 1.

19. A car navigation system having the liquid crystal display device of claim 1.

20. A personal computer having the liquid crystal display device of claim 1.

21. A portable information terminal having the liquid crystal display device of claim 1.

6. An active matrix type liquid crystal display device, comprising:

a display region constituted of display pixels arranged in a matrix form, an image signal having a positive or negative polarity being written in each of the display pixels so as to make an image display, a polarity of the image signal applied to source lines being inversed every 2 or more lines; and

a circuit for forming the image signal which sequentially displays at least four kinds of polarity patterns on the display region.

7. A device according to claim 6, further comprising a circuit which sequentially displays at least four kinds of polarity patterns on the display region every frame or field interval, and sequentially displays them in one period of frames the number of which is the same as that of the kinds of polarity patterns.

8. A device according to claim 6, further comprising a circuit which inverts the polarity of the image signal applied to each of the display pixels every plural frame or plural field periods.

22. A video camera having the liquid crystal display device of claim 6.

23. An electronic still camera having the liquid crystal display device of claim 6.

24. A projector having the liquid crystal display device of claim 6.

25. A head mount display having the liquid crystal display device of claim 6.

26. A car navigation system having the liquid crystal display device of claim 6.

27. A personal computer having the liquid crystal display device of claim 6.

28. A portable information terminal having the liquid crystal display device of claim 6.

9. A method of driving an active matrix type liquid crystal display device which includes a display region constituted of display pixels of x rows by y columns arranged in a matrix form and in which image signals are applied to a first group of n signal lines with a first polarity and to a second group of n signal lines with a second polarity opposite to the first polarity where n is an integer of two or more in a first frame or a first field,

wherein image signals having the second polarity are applied to at least one of the n signal lines of the first group and image signals having the first polarity are applied to at least one of the n signal lines of the second group in a second frame or a second field subsequent to the first frame or the first field,

wherein z kinds of polarity patterns are displayed on the display region where z is an integer of three or more.

10. A method according to claim 9, wherein the Z kinds of polarity patterns are displayed every frame interval, and are sequentially displayed in one period of Z frames.

11. A method according to claim 9, wherein the Z (Z=4) kinds of polarity patterns are sequentially displayed on the display region constituted of the display pixels of x rows by y columns arranged in a matrix form.

12. An active matrix type liquid crystal display device comprising a liquid crystal panel with a display region, the display region including:

a pair of substrates; and

a liquid crystal sealed between the substrates, one of the substrates being provided with N scanning lines, M signal lines, N×

M display pixels respectively disposed at each of crossing portions between the scanning lines and the signal lines, and image signals are applied to a first group of n signal lines with a first polarity and to a second group of n signal lines with a second polarity opposite to the first polarity where n is an integer of two or more in a first frame or a first field,

wherein image signals having the second polarity are applied to at least one of the n signal lines of the first group and image signals having the first polarity are applied to at least one of the n signal lines of the second group in a second frame or a second field subsequent to the first frame or the first field,

wherein at least two kinds of disclination patterns occurred between the first group and the second group are displayed on the display region.

29. A video camera having the liquid crystal display device of claim 12.

30. An electronic still camera having the liquid crystal display device of claim 12.

31. A projector having the liquid crystal display device of claim 12.

32. A head mount display having the liquid crystal display device of claim 12.

33. A car navigation system having the liquid crystal display device of claim 12.

34. A personal computer having the liquid crystal display device of claim 12.

35. A portable information terminal having the liquid crystal display device of claim 12.

13. A method of driving an active matrix type liquid crystal display device which comprises a liquid crystal sealed between a pair of substrates, and a display region constituted of display pixels arranged in a matrix form, in which image signals are applied to a first group of n signal lines with a first polarity and to a second group of n signal lines with a second polarity opposite to the first polarity where n is an integer of two or more in a first frame or a first field,

wherein image signals having the second polarity are applied to at least one of the n signal lines of the first group and image signals having the first polarity are applied to at least one of the n signal lines of the second group in a second frame or a second field subsequent to the first frame or the first field,

wherein at least two kinds of different disclination patterns occurred between the first group and the second group are displayed on the display region.

14. A method according to claim 13, wherein the disclination patterns are sequentially displayed on the display region every frame or field interval.

36. A method of driving an active matrix type liquid crystal display device comprising the steps of:

during a first frame, applying first image signals to a first group of n signal lines with a first polarity and a second-group of n signal lines with a second polarity opposite to said first polarity, wherein said first group of the n signal lines is adjacent to said second group of the n signals with a first boundary therebetween where n is 2 or more; and

during a second frame subsequent to said first frame, applying second image signals to a third group of n signal lines with the first polarity and a fourth group of n signal lines with the second polarity wherein said third group of the n signal lines is adjacent to said fourth group of the n signal lines with a second boundary therebetween, said second boundary being in a different position from said first boundary,

wherein said third group of n signal lines includes at least one signal line of the first group of n signal lines, and said fourth group of n signal lines includes at least one signal line of the first group of n signal lines.

37. A method of driving an active matrix type liquid crystal device comprising the steps of:

during a first field, applying first image signals to a first group of n signal lines with a first polarity and a second group of n signal lines with a second polarity opposite to said first polarity, wherein said first group of the n signal lines is adjacent to said second group of the n signals with a first boundary therebetween where n is 2 or more; and

during a second field subsequent to said first frame, applying second image signals to a third group of n signal lines with the first polarity and fourth group of n signal lines with the second polarity wherein said third group of the n signal lines is adjacent to said fourth group of the n signal lines with a second boundary therebetween said second boundary being in a different position from said first boundary,

wherein said third group of n signal lines includes at least one signal line of the first group of n signal lines, and said fourth group of n signal lines includes at least one signal line of the first group of n signal lines.