DISPLAY DEVICE AND ELECTRONIC EQUIPMENT

• US 20140092353A1
• Filed: 09/20/2013
• Published: 04/03/2014
• Est. Priority Date: 09/28/2012
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Matsushima, Toshiharu
• Granted Patent: US 9,383,614 B2
• Time in Patent Office: Days
• US Class Current: 349/110
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133707 Structures for producing distorted electric fields, e.g. bumps, protrusions, recesses, slits in pixel electrodes
• CPC Class Codes: G02F 1/133738 for homogeneous alignment
• CPC Class Codes: G02F 1/133749 for low pretilt angles, i.e. lower than 15 degrees
• CPC Class Codes: G02F 1/133784 by rubbing
• CPC Class Codes: G02F 1/134372 for fringe field switching [FFS] where the common electrode is not patterned
• CPC Class Codes: G02F 1/13439 characterised by their electrical, optical, physical properties; materials therefor; method of making
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 2201/123 pixel

Abstract

In this display device, an electrode layer for an upper electrode and a lower electrode is formed on an array substrate via a dielectric film, one of the upper electrode and the lower electrode is a pixel electrode, the other thereof is a common electrode, and an opening portion for generating horizontal electric field in a liquid crystal layer is formed in accordance with a shape of the electrode layer in a plan view. A CF substrate has a light-shielding film (BM) including a lateral BM portion. The opening portion has a plurality of slits in an X direction, and an end portion of an outermost slit in a Y direction is concealed by the lateral BM portion overlapped in a Z direction.

Claims

1. A display device having a liquid crystal layer between a first substrate and a second substrate opposed to each other, comprising:

in a case where a substrate in-plane direction corresponding to a screen is defined as first and second directions and a perpendicular direction is defined as a third direction,

an electrode layer which has an upper electrode and a lower electrode opposed to each other and in which an opening portion having a plurality of slits extending in the first direction is formed in the upper electrode or the lower electrode; and

a first light-shielding film portion extending in the first direction and provided in the first or second substrate,

wherein the liquid crystal layer is provided on the electrode layer and liquid crystal molecules in neighboring regions on one side and the other side opposed to each other in a width direction of the slits of the opening portion are rotated in directions opposite to each other to be oriented, and

in the opening portion, for each pixel, at least part of an end portion of at least one outermost slit of outermost slits in the second direction is concealed by the first light-shielding film portion overlapped in the third direction.

2. The display device according to claim 1,

wherein an alignment film is provided between the electrode layer and the liquid crystal layer, and

orientation process in a direction approximately parallel to the first direction which is an extension direction of the slits is applied to the alignment film.

3. The display device according to claim 2,

wherein the first substrate has the electrode layer and a first alignment film positioned between the electrode layer and the liquid crystal layer, and the second substrate has a second alignment film between the second substrate and the liquid crystal layer,

the first alignment film is subjected to rubbing process in a first rubbing direction which is approximately parallel to the first direction as the orientation process,

the second alignment film is subjected to rubbing process in a second rubbing direction which is a direction opposite to the first rubbing direction of the first alignment film as the orientation process,

long axes of liquid crystal molecules in the liquid crystal layer are aligned in the first rubbing direction as an initial orientation state of liquid crystal in the liquid crystal layer, and

in the slits of the opening portion, liquid crystal molecules are oriented so that long axes the liquid crystal molecules are aligned in the first rubbing direction at an OFF time of voltage application to the upper electrode and the lower electrode, and at an ON time of voltage application, liquid crystal molecules in a neighboring region including a first long side which is one side of a pair of long sides of the slit opposed in a width direction are rotated in a clockwise direction and liquid crystal molecules in a neighboring region including a second long side which is the other side thereof are rotated in a counterclockwise direction, and while being rotated in the substrate in-plane direction, the liquid crystal molecules are oriented to stand up in the third direction.

4. The display device according to claim 1,

wherein a width of the first light-shielding film portion in the second direction is equal to or more than a width of a predetermined distance ranging from a line of an end portion of the outermost slit of the opening portion to the outside.

5. The display device according to claim 4,

wherein the first substrate has a first electrode line extending in the first direction and a switching element connected to the first electrode line, which are components constituting the pixel,

the first light-shielding film portion is disposed so as to overlap the first electrode line and the switching element, and

the width of the first light-shielding film portion in the second direction is a width which conceals the first electrode line and the switching element.

6. The display device according to claim 1,

wherein the upper electrode is a common electrode having an opening for each pixel, the lower electrode is a pixel electrode having an electrode portion for each pixel, and a region of the opening of the upper electrode constitutes the opening portion in a plan view corresponding to the screen.

7. The display device according to claim 1,

wherein the upper electrode is a pixel electrode having an electrode portion for each pixel, the lower electrode is a common electrode, and a region positioned outside the upper electrode constitutes the opening portion in a plan view corresponding to the screen.

8. The display device according to claim 6,

wherein the opening portion has, for each pixel, a communication opening portion extending in the second direction and a plurality of slits connected to both sides of the communication opening portion and extending in the first direction,

a plurality of first slits extending in the first direction are arranged on one side of the communication opening portion in the second direction, and a plurality of second slits extending in the first direction are arranged on the other side thereof in the second direction,

one end of a long side of the slit constitutes a corner portion closed by the upper electrode and the other end thereof constitutes a corner portion opened to the communication opening portion,

the plurality of slits on both sides of the communication opening portion are alternately arranged so that positions thereof are shifted in the second direction, and

a long side of the first slit connected to one side of the communication opening portion and a long side of the second slit connected to the other side thereof are aligned on a line in the first direction.

9. The display device according to claim 6,

wherein the opening portion has, for each pixel, a communication opening portion extending in the second direction and a plurality of slits connected to one side of the communication opening portion and extending in the first direction,

the plurality of slits extending in the first direction are arranged in the second direction on one side of the communication opening portion, and

one end of a long side of the slit constitutes a corner portion closed by the upper electrode and the other end thereof constitutes a corner portion opened to the communication opening portion.

10. The display device according to claim 8,

wherein the upper electrode has a plurality of projecting portions for constituting the plurality of slits, and

the slits and the projecting portions are trapezoids which are long in the first direction and have an upper side on a pixel-inner side.

11. The display device according to claim 8,

wherein the upper electrode has a plurality of projecting portions for constituting the plurality of slits, and

the slits and the projecting portions are rectangles which are long in the first direction.

12. The display device according to claim 8,

wherein the first alignment film provided between the electrode layer of the first substrate and the liquid crystal layer is subjected to rubbing process in the first rubbing direction which is approximately parallel to the first direction,

the first and second slits are arranged along the rubbing direction in this order for each pixel, and

the second slit is longer than the first slit.

13. The display device according to claim 1,

wherein the first substrate has the first electrode line parallel to the first direction, a second electrode line parallel to the second direction, and a switching element connected to the first electrode line and the second electrode line for each pixel, and a pixel electrode which is one of the upper electrode and the lower electrode is connected to the switching element,

the first or second substrate has a first light-shielding film portion extending in the first direction and a second light-shielding film portion extending in the second direction,

the first light-shielding film portion overlaps the first electrode line and the switching element,

the second light-shielding film portion overlaps the second electrode line, and

the width of the first light-shielding film portion is larger than a width of the second light-shielding film portion.

14. The display device according to claim 1,

wherein, in the opening portion, a pitch p of the plurality of slits in the second direction satisfies p<

9 μ

m.

15. The display device according to claim 10,

wherein, in a case where the first direction is defined as 0°

, an angle θ

formed by an oblique side in the trapezoids of the projecting portions of the upper electrode and the slits of the opening portion satisfies θ

>

0.5°

.

16. The display device according to claim 8,

wherein a width W of the communication opening portion of the opening portion in the first direction satisfies W≦

4 μ

m.

17. The display device according to claim 1,

wherein, in a case where a cell thickness in the liquid crystal layer is represented as d and a refractive index difference is represented as Δ

n, retardation of the liquid crystal layer R=Δ

n×

d satisfies R≧

0.11×

d.

18. The display device according to claim 1,

wherein an elastic constant K22 regarding rotation of liquid crystal in the liquid crystal layer within a substrate plane satisfies K22>

7.2.

19. The display device according to claim 1, further comprising:

a panel including the first substrate, the second substrate, and the liquid crystal layer;

a first driver connected to a first electrode line of the panel to drive it;

a second driver connected to a second electrode line of the panel to drive it;

a third driver connected to an upper electrode and a lower electrode of the panel to drive them; and

a controller which controls driving of the first to third drivers.

20. Electronic equipment comprising:

the display device according to claim 19;

a control unit which performs display control process to the display device; and

a storage unit which stores display data provided to the display device.