LIQUID CRYSTAL DISPLAY DEVICE

• US 20150116623A1
• Filed: 10/30/2014
• Published: 04/30/2015
• 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 9,250,491 B2
• Time in Patent Office: Days
• US Class Current: 349/43
• 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 liquid crystal display device comprising:

a TFT substrate including an organic passivation film, a common electrode formed on the organic passivation film, an insulating film formed on the common electrode, a pixel electrode formed on the insulating film, and a TFT having a source electrode which is electrically connected to the pixel electrode through a through hole that is formed in the organic passivation film and the interlayer insulating film,

a counter substrate; and

a liquid crystal layer which is interposed between the TFT substrate and the counter substrate,

wherein the through hole has an upper base and a lower base in the organic passivation film,

wherein a diameter of the upper base of the through hole formed in the organic passivation film is greater than a diameter of the lower base,

wherein a taper angle of the upper base of the through hole formed in the organic passivation film is smaller than a taper angle of the lower base.

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

wherein if D is a depth of the through hole formed in the organic passivation film, a taper angle at a distance of D/6 from the upper base is smaller than a taper angle at a distance of D/3 from the upper base.

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

wherein a taper angle at a distance of D/3 from the upper base is smaller than a taper angle at a distance of 2D/3 from the upper base.

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

wherein if D is a depth of the through hole formed in the organic passivation film, a taper angle at a distance of D/3 from the upper base is smaller than a taper angle at a distance of 2D/3 from the upper base.

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

wherein the taper angle at a distance of D/6 from the upper base is between 10 and 30 degrees.

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

wherein the taper angle at a distance of D/3 from the upper base is between 10 and 50 degrees.

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

wherein the taper angle at a distance of 2D/3 from the upper base is 60 degrees or more.

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

wherein the taper angle at a distance of 2D/3 from the upper base is 60 degrees or more.

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

wherein the pixel electrode has a slit which is formed in the through hole.

10. A liquid crystal display device comprising:

a TFT substrate including an organic passivation film, a pixel electrode formed on the organic passivation film, an interlayer insulating film formed on the pixel electrode, a common electrode formed on the interlayer insulating film, and a TFT having a source electrode electrically connected to the pixel electrode through a through hole that is formed in the organic passivation film,

a counter substrate; and

a liquid crystal layer which is interposed between the TFT substrate and the counter substrate,

wherein the through hole has a upper base and a lower base,

wherein a diameter of the upper base is greater than a diameter of the lower base,

wherein a taper angle of the upper base of the through hole formed in the organic passivation film is smaller than a taper angle of the lower base.

11. The liquid crystal display device according to claim 10,

wherein if D is a depth of the through hole formed in the organic passivation film, a taper angle at a distance of D/6 from the upper base is smaller than a taper angle at a distance of D/3 from the upper base.

12. The liquid crystal display device according to claim 11,

wherein a taper angle at a distance of D/3 from the upper base is smaller than a taper angle at a distance of 2D/3 from the upper base.

13. The liquid crystal display device according to claim 10,

wherein if D is a depth of the through hole formed in the organic passivation film, a taper angle at a distance of D/3 from the upper base is smaller than a taper angle at a distance of 2D/3 from the upper base.

14. The liquid crystal display device according to claim 11,

wherein the taper angle at a distance of D/6 from the upper base is between 10 and 60 degrees.

15. The liquid crystal display device according to claim 13,

wherein the taper angle at a distance of D/3 from the upper base is between 10 and 50 degrees.

16. The liquid crystal display device according to claim 11,

wherein the taper angle at a distance of 2D/3 from the upper base is 60 degrees or more.

17. The liquid crystal display device according to claim 13,

wherein the taper angle at a distance of 2D/3 from the upper base is 60 degrees or more.

18. The liquid crystal display device according to claim 10,

wherein the common electrode has a slit which is formed in the through hole.