Horizontal electric field LCD with increased capacitance between pixel and common electrodes
DC
First Claim
1. An active matrix type liquid crystal display device comprising two opposing transparent insulating substrates and liquid crystal interposed therebetween, wherein said liquid crystal is controlled by generating an electric field substantially parallel to the liquid crystal layer with a voltage applied between pixel electrodes and common electrodes both disposed on the first of said substrates, said display device further comprising:
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a plurality of scanning lines and a plurality of signal lines orthogonal to one another;
a thin film transistor provided near each intersection of a scanning line and a signal line;
common electrodes extending substantially parallel to said scanning lines and having a plurality of comb-tooth projections extending toward said scanning lines;
pixel electrodes formed substantially parallel to the comb-tooth projections in gaps between the adjacent comb-tooth projections of said common electrodes when said substrate is viewed from the normal direction, at least a portion of each pixel electrode being opposite to a common electrode interposed by an interlayer insulating film;
an interlayer insulating film disposed between said common electrodes and said pixel electrodes; and
a first alignment film formed above said pixel electrodes interposed by a protective insulating film;
on said second substrate;
a black matrix provided with openings in areas opposite to each of said pixel electrodes; and
a second alignment film; and
said active matrix type liquid crystal display device further comprising;
accumulated capacitance increasing means for obtaining an accumulated capacitance between said pixel electrode and said common electrodes larger than that generated when said interlayer insulating film is of even thickness and flat structure.
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Abstract
An active matrix type liquid crystal display device in a horizontal electric field scheme having a favorable holding characteristic and a reduced feedthrough voltage as well as satisfactory display evenness and reliability with an aperture ratio maintained is disclosed. The device comprises, on the first substrate, a plurality of scanning lines and a plurality of signal lines orthogonal to one another, a thin film transistor intersection of a scanning line and a signal line, the common electrode extending substantially parallel to the scanning lines and having a plurality of comb-tooth projections extending toward the scanning lines, the pixel electrodes formed substantially parallel to the comb-tooth projections in gaps between the adjacent comb-tooth projections of the common electrodes, the interlayer insulating film separating the common electrodes and the pixel electrodes, and a first alignment film formed above the pixel electrode interposed by a protective insulating film. On the second substrate, a black matrix provided with openings provided near in areas opposite to the pixel electrodes, and a second alignment film are provided as well as a dielectric with a predetermined premitivity disposed in the areas in the substrate sandwiched between the comb-tooth projections s of a common electrode and a pixel electrode.
20 Citations
16 Claims
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1. An active matrix type liquid crystal display device comprising two opposing transparent insulating substrates and liquid crystal interposed therebetween, wherein said liquid crystal is controlled by generating an electric field substantially parallel to the liquid crystal layer with a voltage applied between pixel electrodes and common electrodes both disposed on the first of said substrates, said display device further comprising:
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on said first substrate;
a plurality of scanning lines and a plurality of signal lines orthogonal to one another;
a thin film transistor provided near each intersection of a scanning line and a signal line;
common electrodes extending substantially parallel to said scanning lines and having a plurality of comb-tooth projections extending toward said scanning lines;
pixel electrodes formed substantially parallel to the comb-tooth projections in gaps between the adjacent comb-tooth projections of said common electrodes when said substrate is viewed from the normal direction, at least a portion of each pixel electrode being opposite to a common electrode interposed by an interlayer insulating film;
an interlayer insulating film disposed between said common electrodes and said pixel electrodes; and
a first alignment film formed above said pixel electrodes interposed by a protective insulating film;
on said second substrate;
a black matrix provided with openings in areas opposite to each of said pixel electrodes; and
a second alignment film; and
said active matrix type liquid crystal display device further comprising;
accumulated capacitance increasing means for obtaining an accumulated capacitance between said pixel electrode and said common electrodes larger than that generated when said interlayer insulating film is of even thickness and flat structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
a first accumulated capacitance increasing means, wherein said first accumulated capacitance increasing means is a dielectric having a predetermined permittivity provided in the areas of said first substrate between the comb-tooth projections of said common electrodes and said pixel electrodes when the substrate is viewed from the normal direction;
a second accumulated capacitance increasing means, wherein said second accumulated capacitance increasing means comprises a recess formed in at least the portions of the upper surface of said first substrate where said common electrodes and said pixel electrodes overlap when the substrate is viewed normal direction and said accumulated capacitance increasing means is an interlayer insulating film interposed between said common electrodes and said pixel electrodes on a wall surface of said recess;
a third accumulated capacitance increasing means, wherein said accumulated capacitance increasing means is the interlayer insulating film separating said common electrodes and pixel electrodes formed thinner in at least one portion of an area where a common electrode and a pixel electrode overlap when the substrate is viewed from the normal direction; and
a fourth accumulated capacitance increasing means, wherein said accumulated capacitance increasing means includes an interlayer insulating film separating said common electrodes and pixel electrodes formed from a dielectric with a predetermined permittivity in at least one portion of an area where a common electrode and a pixel electrode overlap when the substrate is viewed from the normal direction.
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Specification
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- Resources
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Current AssigneeVista Peak Ventures LLC (Dominion Harbor Enterprises, LLC)
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Original AssigneeNEC Corporation
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InventorsWatanabe, Takahiko, Watanabe, Makoto
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Primary Examiner(s)Ton, Toan
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Assistant Examiner(s)SCHECHTER, ANDREW M
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Application NumberUS09/357,060Time in Patent Office1,058 DaysField of Search349/141, 349/38, 349/39, 349/140, 349/139US Class Current349/141CPC Class CodesG02F 1/133512 Light shielding layers, e.g...G02F 1/134363 for applying an electric fi...
