Liquid crystal display device

• US 9,921,440 B2
• Filed: 09/01/2017
• Issued: 03/20/2018
• Est. Priority Date: 10/31/2013
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Tomioka, Yasushi, Hyodo, Yosuke, Sonoda, Hidehiro, Kunimatsu, Noboru
• Primary Examiner(s): HINES, ANNE M
• Application Number:
  US15/693,564
• Publication Number:
  US 20170363920A1
• Time in Patent Office: 200 Days
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133788 by light irradiation, e.g. linearly polarised light photo-polymerisation
• 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
• CPC Class Codes: G02F 2202/02 organic material
• CPC Class Codes: H01L 27/1218 with a particular composition or structure of the substrate

Abstract

In a liquid crystal display device, a common electrode is formed on an organic passivation film, an interlayer insulating film is formed on the common electrode, a pixel electrode with a slit is formed on the interlayer insulating film, and a through hole is formed in the organic passivation film and the interlayer insulating film, so that the pixel electrode is connected to a source electrode of a TFT through the through hole. Further, the taper angle around the upper base of the through hole is smaller than the taper angle around the lower base. Thus, the alignment film material can easily flow into the through hole when the diameter of the through hole is reduced to connect the pixel and source electrodes, preventing display defects such as uneven brightness due to the absence of the alignment film or due to the alignment film irregularity around the through hole.

Claims

1. A display device comprising:

a first substrate including a source electrode of a switching element, an organic film formed on the source electrode, a first electrode formed on the organic film, an insulating film formed on the first electrode, and a second electrode formed on the insulating film,

wherein the second electrode has a slit and is electrically connected to the source electrode through a through hole, and

wherein the slit extends in the through hole.

2. The display device according to claim 1,

wherein the first electrode is formed in the through hole and is not connected to the source electrode.

3. The display device according to claim 1,

wherein a wall of the through hole has a smooth slope, and

wherein the wall of the through hole which at a position close to the first substrate is steeper than the wall of the through hole which at a distal position from the first substrate.

4. The display device according to claim 1,

wherein the through hole has a first portion which is close to the first substrate, and a second portion which is distant from the first substrate,

wherein a taper angle of the first portion is greater than a taper angle of the second portion.

5. The display device according to claim 4,

wherein the through hole has a folding point which is disposed between the first portion and the second portion.

6. The display device according to claim 4,

wherein the through hole has a step which is disposed between the first portion and the second portion.

7. The display device according to claim 1,

wherein the slit in the through hole does is not overlaps with the source electrode, in a plan view.

8. The display device according to claim 1,

wherein an edge of the source electrode is nearer to the center of the though hole than an edge of the slit in the through hole, in a plan view.

9. The display device according to claim 1,

wherein a cross section of the through hole has a lower base at a proximal position to the first substrate side and an upper base at a distal position to the first substrate side,

wherein a width of the upper base is greater than a width of the source electrode.

10. The display device according to claim 9, further comprising a second substrate opposing to the first substrate,

wherein the second substrate has a light shield film which overlaps with the source electrode in a plan view, and

wherein a width of the light shield film is equal to the width of the source electrode.

11. The display device according to claim 1, further comprising an alignment film covers the first substrate,

wherein the alignment film is a photo alignment film, and

wherein the alignment film is formed in the through hole.

12. A display device comprising:

a first substrate including a source electrode of a switching element, an organic film formed on the source electrode, a first electrode formed on the organic film, an insulating film formed on the first electrode, and a second electrode formed on the insulating film,

wherein the second electrode has a slit and is electrically connected to the source electrode through a through hole,

wherein the slit is extended to the through hole, and

wherein the slit in the through hole does not overlap with the source electrode, in a plan view.

13. The display device according to claim 12, further comprising an alignment film covers the first substrate,

wherein the alignment film is a photo alignment film, and

wherein the alignment film is formed in the through hole.

14. The display device according to claim 12,

wherein the through hole has a first portion which is close to the first substrate, and a second portion which is distant from the first substrate,

wherein a taper angle of the first portion is greater than a taper angle of the second portion.

15. The display device according to claim 14,

wherein a width of the first portion is greater than a width of the source electrode, in a plan view.

16. The display device according to claim 15, further comprising a second substrate opposing to the first substrate,

wherein the second substrate has a light shield film which overlaps with the source electrode, and

wherein a width of the light shield film is equal to the width of the source electrode.