LIQUID CRYSTAL DISPLAY DEVICE

• US 20160327843A1
• Filed: 07/18/2016
• Published: 11/10/2016
• 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
• Granted Patent: US 9,575,385 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 first electrode, an organic film formed on the first electrode, and a second electrode electrically connected to the first electrode through a through hole that is formed in the organic film,

wherein the through hole has a first portion and a second portion which is close to the first substrate than the first portion and arranged between the first substrate and the first portion,

wherein a first taper angle of the first portion is smaller than a second taper angle of the second portion, and

wherein a first diameter of a top of the first portion is greater than a second diameter of a top of the second portion.

2. The display device according to claim 1,

wherein the second electrode is overlapped with at least a portion of the first electrode, in a plan view.

3. The display device according to claim 1,

wherein the through hole is overlapped with at least a portion of the first electrode, in a plan view.

4. The display device according to claim 1,

wherein the organic film is an insulator between the first electrode and the second electrode.

5. The display device according to claim 1,

wherein the through hole has a depth D,

a taper angle at a depth of D/6 from the top of the first portion is smaller than a taper angle at a depth of D/3 from the first portion.

6. The display device according to claim 1,

wherein the through hole has a depth D,

a taper angle at a depth of D/3 from the top of the first portion is smaller than a taper angle at a depth of 2D/3 from the first portion.

7. The display device according to claim 6,

wherein the through hole has a first wall and a second wall,

wherein the first wall have the taper angle in the depth of 2D/3 from the top of the first portion, and the second wall have the taper angle in a depth of D/3 from the first portion.

8. The display device according to claim 7,

wherein a step is formed between the first wall and the second wall.

9. The display device according to claim 1, further comprising

a third electrode formed between the first electrode and the second electrode,

wherein at least a part of the third electrode is formed in the thorough hole.

10. The display device according to claim 9,

wherein the first electrode is used as a light shielding film.

11. The display device according to claim 9,

wherein the third electrode is overlapped with the second electrode,

wherein the second electrode has a slit.

12. The display device according to claim 1, further comprising

a TFT formed on the first substrate,

wherein the first electrode is a source electrode of the TFT.

13. The display device according to claim 12,

wherein the first electrode is electrically connected to a semiconductor layer of the TFT.