Liquid crystal display device of latitudinal electric field type having protruded spacer covers common line

• US 6,549,260 B1
• Filed: 03/23/2000
• Issued: 04/15/2003
• Est. Priority Date: 03/26/1999
• Status: Expired due to Term

• Current Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Original Assignee: NEC Corporation
• Inventors: Shibahara, Hideo
• Primary Examiner(s): Ton, Toan
• Assistant Examiner(s): Qi, Mike
• Application Number:
  US09/533,483
• Time in Patent Office: 1,118 Days
• Field of Search: 349/155, 349/141
• US Class Current: 349/155
• CPC Class Codes: G02F 1/133514 Colour filters
• 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 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]

Abstract

In an active matrix liquid crystal display device of a latitudinal electric field type, i.e., of an In-Plane-Switching type, a protruded spacer is formed on one of a color filter substrate and a TFT substrate, and the spacer is positioned only at a location over a common electrode wire or over a portion of a pixel electrode extended over a gate electrode wire, to thereby reduce the occurrence of a long-term afterimage phenomenon.

Claims

1. A liquid crystal display device of a latitudinal electric field type, comprising:

a first substrate provided with a scan line for controlling a switching element connected to a pixel electrode and a data line, a common electrode arranged parallel to said pixel electrode via insulating film, and a common electrode wire connected to said common electrode and extended in a direction intersecting said data line;

a second substrate disposed opposite said first substrate via liquid crystal layer; and

a protruded spacer formed on at least one of said first substrate and said second substrate so as to fix a gap between said first substrate and said second substrate, said protruded spacer being located over at least one of said common electrode wire and said extended portion of said pixel electrode.

2. A liquid crystal display device of claim 1, wherein said common electrode is divided into a plurality of portions in a lattice shape and extended in a direction intersecting said common electrode wire;

said pixel electrode is divided into a plurality of portions which are arranged to be located between said plurality of portions of said common electrode; and

said protruded spacer is located over said common electrode wire only.

3. A liquid crystal display device of claim 1, wherein said common electrode is divided into a plurality of portions in a lattice shape and extended in a direction intersecting said common electrode wire;

said pixel electrode is divided into a plurality of portions which are arranged to be located between said plurality of portions of said common electrode;

said plurality of portions of said pixel electrode have those end portions thereof distal to said switching element which are extended up to over said common electrode wire and which are commonly connected to each other to thereby constitute an extended portion of said pixel electrode; and

said protruded spacer is located over said extended portion only.

4. A liquid crystal display device of claim 1, wherein said common electrode is divided into a plurality of portions in a lattice shape and extended in a direction intersecting said common electrode wire;

said pixel electrode is divided into a plurality of portions which are arranged to be located between said plurality of portions of said common electrode;

said plurality of portions of said pixel electrode have that partial end portion thereof distal to said switching element which partial end portion is extended beyond said common electrode wire and up to over a scan line at a preceding stage to thereby constitute an extended portion of said pixel electrode; and

said protruded spacer is located over said extended portion only over said scan line at said preceding stage.

5. A liquid crystal display device of claim 2, wherein an opposing area between said protruded spacer and said common electrode wire has a dimension which is narrower than a width of said common electrode wire and which is selected to be within an extent shorter than a distance between both outer sides of said pixel electrode.

6. A liquid crystal display device of claim 3, wherein an opposing area between said protruded spacer and said extended portion of said pixel electrode has a dimension which is narrower than a width of said common electrode wire and which is selected to be within an extent shorter than a length of said connected portion of said pixel electrode.

7. A liquid crystal display device of claim 4, wherein an opposing area between said protruded spacer and said extended portion of said pixel electrode has a dimension which is narrower than a width of said scan line at said preceding stage and which is selected to be within an extent shorter than a distance between both outer sides of said pixel electrode.

8. A liquid crystal display device of claim 1, wherein said second substrate is formed with color filter layers, and said protruded spacer is formed of a lamination of said color filters.

9. A liquid crystal display device of claim 8, wherein said scan line, said common electrode wire and said common electrode are formed on a common plane of said first substrate;

said scan line and said common electrode wire extend in parallel with each other with interposing a pixel area therebetween;

said data line and said pixel electrode are formed in a common plane on said insulating film; and

said protruded spacer has a top contacted with an alignment film formed on said common electrode wire.