LIQUID CRYSTAL DISPLAY DEVICE

Abstract

A liquid crystal display device comprises a first substrate including a first insulation substrate, and rectangular pixel electrodes provided in a matrix on the first insulation substrate and elongated in a first direction, a second substrate opposing the first substrate, and including a second insulation substrate, a counter electrode on the second insulation substrate, and projections on the counter electrode, elongated in a second direction intersecting the first direction, and a liquid crystal layer held between the first and second substrates. The projections extend through pixel regions defined by the pixel electrodes and counter electrode, and are formed asymmetrical with respect to a first imaginary line passing through centers of opposite short sides of each pixel electrode and extending in the first direction, and with respect to a second imaginary line passing through centers of opposite long sides of each pixel electrode and extending in the second direction.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a block diagram illustrating the configuration of a liquid crystal display device according to a first embodiment of the invention;

FIG. 2 is a sectional view illustrating the fundamental structure of the liquid crystal display device of FIG. 1;

FIG. 3 is a schematic view of a liquid crystal display panel for use in the liquid crystal display device of FIGS. 1 and 2, taken from the counter substrate side;

FIG. 4 is a view illustrating an alignment state of the liquid crystal display panel of FIG. 3 in a display mode;

FIG. 5 is a view illustrating a white-display state of the liquid crystal display panel of FIGS. 3 and 4 in the display mode;

FIG. 6 is a schematic view of a liquid crystal display panel different from the panel of FIG. 3, as seen from the counter substrate side;

FIG. 7 is a view illustrating an alignment state of the liquid crystal display panel of FIG. 6 in the display mode;

FIG. 8 is a schematic view of a liquid crystal display panel different from the panel of FIG. 3, taken from the counter substrate side;

FIG. 9 is a view illustrating an alignment state of the liquid crystal display panel of FIG. 8 in the display mode;

FIG. 10 is a schematic view of a liquid crystal display panel as a comparative example for the panels of FIGS. 3, 6 and 8, taken from the counter substrate side;

FIG. 11 is a view illustrating an alignment state of the liquid crystal display panel of FIG. 10 in the display mode;

FIG. 12 is a view illustrating a white-display state of the liquid crystal display panel of FIGS. 10 and 11 in the display mode;

FIG. 13 is a schematic view of a liquid crystal display panel according to a second embodiment of the invention, taken from the counter substrate side;

FIG. 14 is a view illustrating an alignment state of the liquid crystal display panel of FIG. 13 in the display mode;

FIG. 15 is a schematic view of a liquid crystal display panel similar to the panel of FIG. 13, taken from the counter substrate side;

FIG. 16 is a view illustrating an alignment state of the liquid crystal display panel of FIG. 15 in the display mode;

FIG. 17 is a schematic view of a liquid crystal display panel according to a third embodiment of the invention, taken from the counter substrate side; and

FIG. 18 is a view illustrating an alignment state of the liquid crystal display panel of FIG. 17 in the display mode.

Claims

1. A liquid crystal display device comprising: a first substrate including a first insulation substrate, and a plurality of rectangular pixel electrodes provided in a matrix on the first insulation substrate and elongated in a first direction;a second substrate opposing the first substrate, and including a second insulation substrate, a counter electrode provided on the second insulation substrate and corresponding to the pixel electrodes, and a plurality of projections provided on the counter electrode and elongated in a second direction intersecting the first direction; anda liquid crystal layer held between the first and second substrates,the projections extending through a plurality of pixel regions defined by the pixel electrodes and the counter electrode, the projections being formed asymmetrical with respect to a first imaginary line passing through centers of opposite short sides of each of the pixel electrodes and extending in the first direction, and with respect to a second imaginary line passing through centers of opposite long sides of each of the pixel electrodes and extending in the second direction.

2. The liquid crystal display device according to claim 1, wherein the projections are formed rotationally symmetrical with respect to an intersection of the first and second imaginary lines in the pixel regions.

3. The liquid crystal display device according to claim 1, wherein each of the projections is divided, in a corresponding one of the pixel regions, into four divisions by the first and second imaginary lines, and diametrically opposite two of the divisions are greater than remaining two of the divisions.

4. The liquid crystal display device according to claim 1, wherein each of the projections is divided, in a corresponding one of the pixel regions, into four divisions by the first and second imaginary lines, diametrically opposite two of the divisions having outer edges intersecting one of the long sides of said each electrode at a first angle, remaining two of the divisions having outer edges intersecting another of the long sides of said each electrode at a second angle, the first angle and the second angle being other than 90 degrees.

5. The liquid crystal display device according to claim 1, wherein each of the projections includes a stripe portion extending in the second direction, a plurality of first convex portions projecting from one side of the stripe portion, and a plurality of second convex portions projecting from another side of the strip portion in a direction opposite to a direction in which the first convex portions project, the first and second convex portions being provided alternately in the second direction.

6. The liquid crystal display device according to claim 5, wherein the first and second convex portions are formed rectangular.

7. The liquid crystal display device according to claim 1, wherein the projections each have opposite sawtooth edges.

8. The liquid crystal display device according to claim 1, wherein the short sides of the pixel electrodes have a length of 40 μm or less.

9. A liquid crystal display device comprising: a first substrate including a first insulation substrate, and a plurality of rectangular pixel electrodes provided in a matrix on the first insulation substrate and elongated in a first direction;a second substrate opposing the first substrate, and including a second insulation substrate, a counter electrode provided on the second insulation substrate and corresponding to the pixel electrodes, and a plurality of projections provided on the counter electrode and elongated in a second direction intersecting the first direction; anda liquid crystal layer held between the first and second substrates,the projections each including a plurality of convex portions,the convex portions being formed to make, asymmetrical with respect to a first imaginary line and a second imaginary line, liquid crystal alignment pattern of each of a plurality of pixel regions defined by the pixel electrodes and the counter electrode, the first imaginary line passing through centers of opposite short sides of each of the pixel electrodes and extending in the first direction, the second imaginary line passing through centers of opposite long sides of said each pixel electrode and extending in the second direction.

10. The liquid crystal display device according to claim 9, wherein the convex portions are formed to make the liquid crystal alignment pattern of said each pixel region rotationally symmetrical with respect to an intersection of the first and second imaginary lines.

11. The liquid crystal display device according to claim 9, wherein the pixel regions have same liquid crystal alignment.

12. A liquid crystal display device comprising: a first substrate including a first insulation substrate, and a plurality of rectangular pixel electrodes provided in a matrix on the first insulation substrate and elongated in a first direction;a second substrate opposing the first substrate, and including a second insulation substrate, a counter electrode provided on the second insulation substrate and corresponding to the pixel electrodes, and a plurality of projections provided on the counter electrode and elongated in a second direction intersecting the first direction; anda liquid crystal layer held between the first and second substrates,each of the pixel electrodes being divided at a position corresponding to a corresponding one of the projections, and having a first rectangular electrode region and a second rectangular electrode region shifted from each other in the second direction,patterns of each pair of adjacent ones of the pixel electrodes, which are adjacent in the second direction, being mirror patterns with respect to a boundary of said each pair,said each pair having portions spaced by a first distance and portions spaced by a second distance.

13. The liquid crystal display device according to claim 12, wherein the first distance is shorter than the second distance, the first distance is longer than 0 μm and not more than 4 μm, and the second distance is not less than 8 μm and less than a sum of the first distance and twice a length of each of the pixel electrodes in the second direction.

14. The liquid crystal display device according to claim 12, wherein the patterns of said each pair of adjacent ones of the pixel electrodes are not mirror patterns with respect to an imaginary line extending in the second direction in which the projections are elongated.

15. The liquid crystal display device according to claim 12, wherein the first and second directions are perpendicular to each other, and the pixel electrodes are formed rotationally symmetrical with respect to respective axes the pixel electrodes.

16. A liquid crystal display device comprising: a first substrate including a first insulation substrate, and a plurality of rectangular pixel electrodes provided in a matrix on the first insulation substrate and elongated in a first direction;a second substrate opposing the first substrate, and including a second insulation substrate, a counter electrode provided on the second insulation substrate and corresponding to the pixel electrodes, and a plurality of projections provided on the counter electrode and elongated in a second direction intersecting the first direction; anda liquid crystal layer held between the first and second substrates and containing a chiral agent.

17. The liquid crystal display device according to claim 16, wherein the chiral agent causes liquid crystal molecules of the liquid crystal layer to have a rightward twisted structure.

18. The liquid crystal display device according to claim 16, wherein the chiral agent causes liquid crystal molecules of the liquid crystal layer to have a leftward twisted structure.