Active-matrix in-plane switching mode LCD panel having multiple common electrode voltage sources
AssigneeNEC LCD Technologies, Ltd.
InventorsMakoto Watanabe, Takahiko Watanabe
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Abstract
An in-line switching mode LCD panel has three groups of common electrode lines corresponding to three colors defined by color layers in the pixels. The potentials of the groups of the common electrode lines are adjusted independently of one another so that the flicker level for the corresponding pixels assumes a minimum by compensating the difference in the feed-through voltage between the pixels.
Claims9
A liquid crystal display (LCD) panel assembly comprising:
- a first panel;
- a second panel;
- and
- an LCD layer sandwiched therebetween,
- said first panel including:
- a first substrate;
- a plurality of pixel elements arranged in a matrix on said first substrate, each said pixel element including a thin film transistor (TFT), a pixel electrode and a common electrode, said pixel electrode and said common electrode generating therebetween a lateral electric field parallel to a surface of said first substrate;
- a plurality of common electrode lines each connected to corresponding common electrodes;
- a plurality of scanning lines each disposed for a corresponding row of said pixel elements and connected to gates of said TFTs in the corresponding row;
- and
- a plurality of video signal lines each disposed for a corresponding column of said pixel elements and connected to source/drain paths of said TFTs in said corresponding column,
- said common electrode lines forming a plurality of groups each corresponding to said pixel elements having an equal total capacitance between said pixel electrode and said common electrode in the pixel elements, each of said groups being applied with a separate voltage independently of voltages applied to another of said groups.
A liquid crystal display (LCD) panel assembly comprising:
- a first panel;
- a second panel;
- and
- an LCD layer sandwiched therebetween,
- said first panel including:
- a first substrate;
- a plurality of pixel elements each including a thin film transistor (TFT), a pixel electrode and a common electrode, said pixel electrode and said common electrode generating therebetween a lateral electric field parallel to a surface of said first substrate;
- a plurality of common electrode lines each disposed for said pixel elements in a corresponding column and connected to corresponding said common electrodes;
- a plurality of scanning lines each disposed for a corresponding row of said pixel elements and connected to gates of said TFTs in the corresponding row;
- a plurality of video signal lines each disposed for a corresponding column of said pixel elements and connected to source/drain paths of said TFTs in said corresponding column;
- a resistor connected between each adjacent two of said common electrode lines;
- and
- at least three nodes each connecting said resistor and said common electrode line being applied with separate voltages independently of each other,
- wherein said separate voltages and resistances of said resistors are selected so that one of said common electrode lines corresponding to proximal ends of said scanning lines is applied with a lower voltage compared to another of said common electrode lines corresponding to distal ends of said scanning lines, and
- wherein a center one of said at least three nodes has a higher voltage than either of said common electrode lines corresponding to said proximal ends and said common electrode lines corresponding to said distal ends.
A method of reducing flicker in a liquid crystal display (LCD) panel, said LCD panel having a plurality of pixel elements arranged in a matrix on said first substrate, each said pixel element including a thin film transistor (TFT), a pixel electrode and a common electrode, said method comprising:
- categorizing said common electrodes of said pixel elements into groups, based on a capacitance between said pixel electrode and said common electrode;
- and
- applying a common electrode voltage to each said group, each said group having a different voltage level for said common electrode voltage.
Dependencies are inferred from the claim text.