Driving method of active matrix display device

• US 20060017679A1
• Filed: 06/27/2005
• Published: 01/26/2006
• Est. Priority Date: 03/26/1996
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Hirakata, Yoshiharu, Takemura, Yasuhiko
• Granted Patent: US 7,336,249 B2
• Time in Patent Office: Days
• US Class Current: 345/90
• CPC Class Codes: G09G 2300/0434 Flat panel display in which a field is applied parallel to the display plane
• CPC Class Codes: G09G 2330/025 Reduction of instantaneous peaks of current
• CPC Class Codes: G09G 2330/04 Display protection
• 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

Abstract

In a liquid crystal display device of the in-plane switching mode (IPS mode), the potential of data that is output from a data driver is set at values between potentials that are given to common lines. Two levels, i.e., high and low levels, are prepared for the potential to be given to the common lines and the potential is inverted between those levels in every field, whereby the polarity of a voltage between both electrodes of a pixel is inverted. As a result, the potential variation ranges of signals that are output from the data driver and a scan driver can be greatly reduced from those of the conventional case, which contributes to reduction in the power consumption of the drivers. Since the voltage applied to a switching element for controlling each pixel can be reduced, the load of the switching element can also be reduced.

Claims

1. A driving method for an active matrix display device of an in-plane switching mode comprising:

a plurality of scan lines arranged so as not to intersect each other;

a plurality of data lines arranged so as to cross said scan lines;

a plurality of common lines arranged corresponding to respective scan lines so as not to cross said scan lines;

a pixel capacitor element having a pair of electrodes, said pixel capacitor element being provided for each intersection of said scan lines and said data lines, one of said electrodes being connected to a corresponding one of said common lines; and

a switching element comprising a control electrode and input and output terminals, said switching element being provided for each intersection of said scan lines and said data lines, said input terminal being connected to a corresponding one of said data lines, said output terminal being connected to the other of said electrodes of said pixel capacitor element, said control electrode being connected to a corresponding one of said scan lines, comprising the steps of;

keeping each of said common lines at potential being selected from V_H and V_L, where V_H>

V_L, during almost all of a period when a selection pulse is not applied to a corresponding one of said scan lines; and

applying to said data lines a signal potential V_D where V_L≦

V_D≦

V_H.