Liquid crystal display with reduced power dissipation and/or reduced vertical striped shades in frame control and control method for same

• US 5,790,092 A
• Filed: 07/25/1995
• Issued: 08/04/1998
• Est. Priority Date: 07/28/1994
• Status: Expired due to Term

• Current Assignee: Gold Charm Limited (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Moriyama, Hiroaki
• Primary Examiner(s): Liang, Regina
• Application Number:
  US08/506,705
• Time in Patent Office: 1,106 Days
• Field of Search: 345/87, 345/94, 345/95, 345/96, 345/99, 345/208, 345/209, 345/210
• US Class Current: 345/96
• 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

Abstract

A liquid crystal display is driven so that an arbitrary pair of neighboring ones of M×N matrixed pixels in a row direction are driven by reversing a polarity of a signal potential in either thereof from that in the other thereof, an arbitrary pair of neighboring combinations of neighboring two of the M×N pixels in a column direction are driven by reversing the polarity of the signal potential in each of the neighboring two in either thereof from that in each of the neighboring two in the other thereof, and the polarity of the signal potential in each of the M×N pixels is reversed every frame. Four of the pixels in an arbitrary two-row by two-column area and four of the pixels in an arbitrary quartet of continuous rows in an arbitrary column both contain four drive phases of a pair of drive voltages.

Claims

1. A liquid crystal display, comprising:

a display comprising a matrix of pixels each having a common reference potential; and

a drive means for driving the display wherein,

every other one of said pixels in a row direction of the matrix are driven by a signal having a reversed polarity relative to the reference potential, and

every other pair of said pixels in a column direction of the matrix are driven by said signal having a reversed polarity relative to the reference potential, and

the polarity of the signal supplied to each of the pixels is reversed every frame.

2. A liquid crystal display according to claim 1, wherein the polarity of the signal is reversed depending on an exclusive logical sum between a half-frequency signal of a vertical synchronizing signal of the display and a fourth-frequency signal of a horizontal synchronizing signal of the display.

3. A liquid crystal display according to claim 1 wherein the display further comprises:

a first transparent insulating substrate member;

a second transparent insulating substrate member opposing the first substrate member;

M gate lines arranged in parallel with each other on the first substrate member, where M is a predetermined positive integer;

N source lines arranged in parallel with each other on the first substrate member, where N is a predetermined positive integer;

the M gate lines and the N source lines crossing with each other in an electrically isolated manner and cooperating with each other to have therebetween M×

N cross points and to define therebetween M×

N enclosed areas associated with the M×

N cross points in a one to one corresponding manner where the matrix of pixels has M rows and N columns;

the pixels each comprising;

a thin film transistor formed in a vicinity of one of the M×

N cross points;

a pixel electrode formed in one of the M×

N enclosed areas corresponding to said one of the M×

N cross points;

the pixel electrode being chargeable to have the signal potential developed thereon;

an opposite electrode formed on the second substrate member;

the opposite electrode being charged to have a reference potential developed thereon; and

a liquid crystal filled between the first and second substrate members;

the liquid crystal being responsive to the signal potential.

4. A liquid crystal display according to claim 3, wherein the thin film transistor is made of one of amorphous silicon and crystalline silicon.

5. A liquid crystal display, comprising:

a display comprising a matrix of pixels each having a common reference potential developed therein; and

a drive means for driving the display so that the pixels are each respectively supplied with alternately selected one of a first drive voltage and a second drive voltage,

said first drive voltage having a pair of drive phases, said pair comprising a relatively small voltage with a positive polarity relative to the reference voltage and a relatively large voltage with a negative polarity relative to the reference voltage, and

said second drive voltage having a pair of drive phases, comprising the relatively small voltage with the negative polarity and the relatively large voltage with the positive polarity to thereby display an intermediate tone,

wherein four of the pixels in an arbitrary two-row by two-column area of the matrix and four of the pixels in an arbitrary quartet of continuous rows in an arbitrary column of the matrix both contain the first drive voltage and the second drive voltage.

6. A liquid crystal display according to claim 5 wherein any pair of neighboring ones of the pixels in an arbitrary row or an arbitrary column of the matrix contain a different two of the drive phases of the first drive voltage and the drive phases of the second drive voltage.

7. A liquid crystal display according to claim 5, wherein an arbitrary pair of neighboring ones of the pixels in an arbitrary row of the matrix are driven by one of the first drive voltage with either of the positive and negative polarities and the other pixel in said pair by the second drive voltage with the other of said positive and negative polarities,

wherein an arbitrary pair of neighboring pairs of the pixels in an arbitrary column of the matrix are driven either by one of the first and second drive voltages with either of the positive and negative polarities and the other pair by said one of the first and second drive voltages with the other of said positive and negative polarities, and

wherein the polarities of the drive voltages to each of said pixels is reversed every frame.

8. A control method for driving a liquid crystal display including a display comprising a matrix of pixels, comprising the steps of:

developing a common reference potential in each of the pixels;

driving the display in a row direction so that every other pixel in the row direction of the matrix is driven by a signal having a reversed polarity relative to the reference potential;

driving the display in a column direction wherein every other pair of pixels in the column direction of the matrix are driven by a signal having a reversed polarity relative to the reference potential; and

reversing the polarity of the signal potential in each of the pixels every frame.

9. A control method according to claim 8, further comprising a step of reversing the polarity of the signal potential depending on an exclusive logical sum between a half-frequency signal of a vertical synchronizing signal of the display and a fourth-frequency signal of a horizontal synchronizing signal of the display.

10. A control method for driving a liquid crystal display including a display comprising a matrix of pixels, comprising the steps of:

developing a common reference potential in each of the pixels;

providing a first drive voltage comprising a pair of drive phases comprising one of a small voltage with a positive polarity relative to the reference potential and a large voltage with a negative polarity relative to the reference potential;

providing a second drive voltage having a pair of drive phases comprising one of the small voltage with the negative polarity relative to the reference potential and the other with the large voltage with the positive polarity relative to the reference potential to thereby display an intermediate tone, wherein four of the pixels in an arbitrary two-row by two-column area of the matrix and four of the pixels in an arbitrary quartet of continuous rows in an arbitrary column of the matrix both contain both the pair of drive phases of the first drive voltage and the pair of drive phases of the second drive voltage.

11. A control method according to claim 10, wherein any pair of neighboring ones of the pixels in an arbitrary row or an arbitrary column of the matrix contain a different two of the drive phases of the first drive voltage and the drive phases of the second drive voltage.

12. A control method according to claim 10 wherein neighboring ones of the pixels in an arbitrary row of the matrix are driven either by the first drive voltage with one of the positive and negative polarities and the other by the second drive voltage with the other of the positive and negative polarities,

wherein neighboring pairs of the pixels in an arbitrary column of the matrix are driven by one of the first and second drive voltages with one of the positive and negative polarities and the other pair by one of the first and second drive voltages with the other of the positive and negative polarities, and

wherein the positive and negative polarities driving the pixels are reversed every frame.

13. A method of driving a matrix of pixels in a display device, comprising steps of:

providing a common reference potential for each of said pixels;

in a first frame;

driving every other one of said pixels in a row direction of said matrix with a positive polarity drive signal with respect to said common reference potential, and driving remaining ones of said pixels in said row direction with a negative polarity drive signal with respect to said common reference potential; and

driving every other pair of pixels in a column direction of said matrix with a positive polarity drive signal with respect to said common reference potential, and driving remaining pairs of said pixels with a negative polarity drive signal with respect to said common reference potential; and

in a second frame;

reversing the polarities of the drive signals driving each of said pixels in said matrix with respect to the polarities in said first frame.

14. A method of driving a matrix of pixels in a display device as recited in claim 13 wherein said step of reversing the polarities of the drive signals comprises calculating an exclusive logical sum between a half-frequency signal of a vertical synchronizing signal of the display and a fourth-frequency signal of a horizontal synchronizing signal of the display device.

15. A method of driving a matrix of pixels in a display device, comprising steps of:

providing four phased drive signals;

driving every quartet of said pixels in a first two rows and every other two rows thereafter of said matrix with a first combination of said four phased drive signals; and

driving a second quartet of pixels in a second two rows and every other two rows thereafter of said matrix with a second combination of said four phased drive signals,

wherein said four phased drive signals are labeled one, two, three, four, respectively, and

wherein in a first frame, said first combination comprises repeating a pattern one, three, four, two; and

said second combination comprises repeating a pattern three, one, two, four.

16. A method of driving a matrix of pixels in a display device as recited in claim 15, further comprising the steps:

in a second frame, switching said four phased drive signals to drive diagonal pixels in said quartets of pixels

wherein said first combination comprises repeating pattern two, four, three, one; and

wherein said second combination comprises repeating pattern four, two, one, three.