Liquid crystal display device

• US 8,797,496 B2
• Filed: 07/17/2012
• Issued: 08/05/2014
• Est. Priority Date: 07/21/2011
• Status: Active Grant

• Current Assignee: Japan Display Incorporated
• Original Assignee: Japan Display Incorporated
• Inventors: Tomioka, Yasushi, Kunimatsu, Noboru, Sonoda, Hidehiro, Imanishi, Yasuo, Igeta, Koichi
• Primary Examiner(s): NGUYEN, THANH NHAN P
• Application Number:
  US13/550,632
• Publication Number:
  US 20130021552A1
• Time in Patent Office: 749 Days
• Field of Search: None
• US Class Current: 349/157
• CPC Class Codes: G02F 1/1339 Gaskets; Spacers; Sealing of cells
• CPC Class Codes: G02F 1/13392 spacers dispersed on the cell substrate, e.g. spherical particles, microfibres
• CPC Class Codes: G02F 1/13394 spacers regularly patterned on the cell subtrate, e.g. walls, pillars G02F1/133377 takes precedence
• CPC Class Codes: G02F 1/13396 Spacers having different sizes
• CPC Class Codes: G02F 1/136227 Through-hole connection of the pixel electrode to the active element through an insulation layer

Abstract

In a liquid crystal display device, a TFT substrate retains a contact hole that is formed in a passivation film, and is for connecting the TFT and the pixel electrode. And an opposite substrate retains a columnar spacer for ensuring a cell gap, and a columnar projection for misalignment prevention formed at a position corresponding to a position of the contact hole. Accordingly, misalignment between the TFT substrate and the opposite substrate is suppressed, occurrence of uneven brightness due to misalignment between pixel regions and a bright spot caused by shaving of an orientation film is prevented, and a favorable image is obtained.

Claims

1. A liquid crystal display device, comprising:

a thin-film transistor (TFT) substrate in which a pixel electrode, and a TFT are formed in a matrix;

an opposite substrate in which a color filter is formed at a position corresponding to a position of the pixel electrode and that is arranged with a predetermined gap with the TFT substrate; and

a liquid crystal retained in the gap;

wherein

the TFT substrate retains a contact hole that is formed in a passivation film, and is for connecting the TFT and the pixel electrode;

the opposite substrate retains a columnar spacer for ensuring a cell gap, and a columnar projection for misalignment prevention formed at a position corresponding to a position of the contact hole; and

the number of the columnar projection is less than the number of the columnar spacer.

2. The liquid crystal display device according to claim 1, wherein the passivation film includes an organic passivation film.

3. The liquid crystal display device according to claim 1, wherein the passivation film is comprised only of an inorganic passivation film.

4. The liquid crystal display device according to claim 1, wherein a difference Δ

h between height h1 of the columnar projection and height h2 of the columnar spacer is equal to or less than depth z of the contact hole.

5. The liquid crystal display device according to claim 4, wherein the columnar projection abuts on a bottom part of the contact hole when an excessive force is applied thereto.

6. The liquid crystal display device according to claim 1, wherein height h1 of the columnar projection is larger than a cell gap d, and is smaller than a sum of the cell gap d and depth z of the contact hole.

7. The liquid crystal display device according to claim 1, wherein the contact hole has an inclining part diameter of which is larger at an upper part.

8. The liquid crystal display device according to claim 1, wherein a diameter of a top part of the columnar projection is smaller than a diameter of an upper part of the contact hole.

9. The liquid crystal display device according to claim 1, wherein a cross-sectional area of the columnar projection is smaller than a cross-sectional area of the columnar spacer.

10. The liquid crystal display device according to claim 1, which is an in-plane switching (IPS) liquid crystal display device.

11. The liquid crystal display device according to claim 1, which is a twisted nematic (TN) or vertical alignment (VA) liquid crystal display device.

12. A liquid crystal display device comprising:

a thin-film transistor (TFT) substrate in which a pixel electrode, and a TFT are formed in a matrix;

an opposite substrate in which a color filter is formed at a position corresponding to a position of the pixel electrode and that is arranged with a predetermined gap with the TFT substrate; and

a liquid crystal retained in the gap;

wherein

the TFT substrate retains a contact hole that is formed in a passivation film, and is for connecting the TFT and the pixel electrode;

the opposite substrate retains a columnar spacer for ensuring a cell gap, and a columnar projection for misalignment prevention formed at a position corresponding to a position of the contact hole; and

density of the columnar projection is higher at a peripheral area of a liquid crystal panel than at a center region of the liquid crystal panel.

13. The liquid crystal display device according to claim 12, wherein the columnar spacer is arranged substantially uniformly over an entire screen of the liquid crystal panel.

14. The liquid crystal display device according to claim 12, wherein the columnar spacer is formed at a position other than the position corresponding to the position of the contact hole.

15. A liquid crystal display device comprising:

a thin-film transistor (TFT) substrate in which a pixel electrode, and a TFT are formed in a matrix;

an opposite substrate in which a color filter is formed at a position corresponding to a position of the pixel electrode and that is arranged with a predetermined gap with the TFT substrate; and

a liquid crystal retained in the gap;

wherein

the TFT substrate retains a contact hole that is formed in a passivation film, and is for connecting the TFT and the pixel electrode;

the opposite substrate retains a columnar spacer for ensuring a cell gap, and a columnar projection for misalignment prevention formed at a position corresponding to a position of the contact hole; and

an interval between the columnar projections is larger than an interval between the columnar spacers.