LIQUID CRYSTAL DISPLAY DEVICE AND METHOD OF PRODUCING LIQUID CRYSTAL DISPLAY DEVICE

• US 20190302552A1
• Filed: 03/26/2019
• Published: 10/03/2019
• Est. Priority Date: 03/29/2018
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: MUTO, YUTA, TANIIKE, KOHSHIROH
• Granted Patent: US 10,642,117 B2
• Time in Patent Office: Days
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take 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 1/133711 by organic films, e.g. polymeric films
• CPC Class Codes: G02F 1/133738 for homogeneous alignment
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence

Abstract

The liquid crystal display device according to the present invention includes: a thin-film transistor substrate, wherein the thin-film transistor substrate includes an organic insulating film disposed on a drain electrode and provided with a contact hole, the contact hole includes first, second, third, and fourth side wall portions in the given order, an inclination of an upper portion of the second side wall portion is gentler than an inclination of an upper portion of each of the first and third side wall portions, and the contact hole satisfies W2>L, wherein L is a distance from an upper end of the first side wall portion to an upper end of the third side wall portion on a first straight line, and W2 is a maximum distance between one and another upper end of the second side wall portion on a third straight line parallel to the first straight line.

Claims

1. A liquid crystal display device comprising:

a thin-film transistor substrate;

a counter substrate facing the thin-film transistor substrate; and

a liquid crystal layer held between the thin-film transistor substrate and the counter substrate,

wherein the thin-film transistor substrate includes a thin-film transistor including a drain electrode, an organic insulating film disposed on the drain electrode, and a pixel electrode disposed on the organic insulating film,

the pixel electrode is connected to the drain electrode through a contact hole provided in the organic insulating film,

the contact hole provided in the organic insulating film includes a bottom portion and a side wall surrounding the bottom portion,

the side wall includes a first side wall portion, a second side wall portion, a third side wall portion, and a fourth side wall portion in the given order in a circumferential direction of the contact hole,

in a plan view, while the first side wall portion, the bottom portion, and the third side wall portion are arranged in the given order on a first straight line, the second side wall portion, the bottom portion, and the fourth side wall portion are arranged in the given order on a second straight line orthogonal to the first straight line,

an inclination of an upper portion of the second side wall portion is gentler than an inclination of an upper portion of each of the first side wall portion and the third side wall portion, and

the contact hole provided in the organic insulating film satisfies W2>

L, wherein L is a distance from an upper end of the first side wall portion to an upper end of the third side wall portion on the first straight line, and W2 is a maximum distance between one upper end and another upper end of the second side wall portion on a third straight line parallel to the first straight line.

2. The liquid crystal display device according to claim 1,

wherein an inclination angle of the upper portion of each of the first side wall portion and the third side wall portion is more than 20°

, and

an inclination angle of the upper portion of the second side wall portion is 10°

or more and 20°

or less.

3. The liquid crystal display device according to claim 1,

wherein the inclination of the upper portion of the second side wall portion is gentler than an inclination of an upper portion of the fourth side wall portion.

4. The liquid crystal display device according to claim 3,

wherein an inclination angle of the upper portion of the fourth side wall portion is more than 20°

.

5. The liquid crystal display device according to claim 1,

wherein an inclination of an upper portion of the fourth side wall portion is gentler than the inclination of the upper portion of each of the first side wall portion and the third side wall portion, and

the contact hole provided in the organic insulating film satisfies W4>

L, wherein W4 is a maximum distance between one upper end and another upper end of the fourth side wall portion on a fourth straight line parallel to the first straight line.

6. The liquid crystal display device according to claim 5,

wherein an inclination angle of the upper portion of the fourth side wall portion is 10°

or more and 20°

or less.

7. A method of producing a liquid crystal display device including a thin-film transistor substrate, a counter substrate facing the thin-film transistor substrate, and a liquid crystal layer held between the thin-film transistor substrate and the counter substrate,

wherein the thin-film transistor substrate includes a thin-film transistor including a drain electrode, an organic insulating film disposed on the drain electrode, and a pixel electrode disposed on the organic insulating film,

the pixel electrode is connected to the drain electrode through a contact hole provided in the organic insulating film,

the contact hole provided in the organic insulating film includes a bottom portion and a side wall surrounding the bottom portion,

the side wall includes a first side wall portion, a second side wall portion, a third side wall portion, and a fourth side wall portion in the given order in a circumferential direction of the contact hole,

in a plan view, while the first side wall portion, the bottom portion, and the third side wall portion are arranged in the given order on a first straight line, the second side wall portion, the bottom portion, and the fourth side wall portion are arranged in the given order on a second straight line orthogonal to the first straight line,

an inclination of an upper portion of the second side wall portion is gentler than an inclination of an upper portion of each of the first side wall portion and the third side wall portion, and

the contact hole provided in the organic insulating film satisfies W2>

L, wherein L is a distance from an upper end of the first side wall portion to an upper end of the third side wall portion on the first straight line, and W2 is a maximum distance between one upper end and another upper end of the second side wall portion on a third straight line parallel to the first straight line,

the method comprising applying an alignment film material onto the thin-film transistor substrate.

8. The method of producing a liquid crystal display device according to claim 7,

wherein an inclination angle of the upper portion of each of the first side wall portion and the third side wall portion is more than 20°

, and

an inclination angle of the upper portion of the second side wall portion is 10°

or more and 20°

or less.

9. The method of producing a liquid crystal display device according to claim 7,

wherein the applying an alignment film material includes adding dropwise the alignment film material onto the thin-film transistor substrate by an ink jet method.

10. The method of producing a liquid crystal display device according to claim 9,

wherein the applying an alignment film material includes adding dropwise the alignment film material sequentially in a predetermined direction parallel to the second straight line.

11. The method of producing a liquid crystal display device according to claim 10,

wherein the inclination of the upper portion of the second side wall portion is gentler than an inclination of an upper portion of the fourth side wall portion, and

the applying an alignment film material includes adding dropwise the alignment film material sequentially from a second side wall portion side toward a fourth side wall portion side.

12. The method of producing a liquid crystal display device according to claim 10,

wherein the inclination of the upper portion of the second side wall portion is gentler than an inclination of an upper portion of the fourth side wall portion, and

the applying an alignment film material includes adding dropwise the alignment film material sequentially from a fourth side wall portion side toward a second side wall portion.

13. The method of producing a liquid crystal display device according to claim 11,

wherein an inclination angle of the upper portion of the fourth side wall portion is more than 20°

.

14. The method of producing a liquid crystal display device according to claim 12,

wherein an inclination angle of the upper portion of the fourth side wall portion is more than 20°

.

15. The method of producing a liquid crystal display device according to claim 10,

wherein an inclination of an upper portion of the fourth side wall portion is gentler than the inclination of the upper portion of each of the first side wall portion and the third side wall portion, and

the contact hole provided in the organic insulating film satisfies W4>

L, wherein W4 is a maximum distance between one upper end and another upper end of the fourth side wall portion on a fourth straight line parallel to the first straight line.

16. The method of producing a liquid crystal display device according to claim 15,

wherein an inclination angle of the upper portion of the fourth side wall portion is 10°

or more and 20°

or less.