Liquid-crystal display panel and repair method thereof

• US 6,476,882 B1
• Filed: 07/11/1997
• Issued: 11/05/2002
• Est. Priority Date: 07/11/1996
• Status: Expired due to Term

• Current Assignee: Vista Peak Ventures LLC (Dominion Harbor Enterprises, LLC)
• Original Assignee: NEC Corporation
• Inventors: Sakurai, Hiroshi
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): NGUYEN, DUNG T
• Application Number:
  US08/891,385
• Time in Patent Office: 1,943 Days
• Field of Search: 349/44, 349/54, 349/55, 257/59, 257/72
• US Class Current: 349/55
• CPC Class Codes: G02F 1/136259 Repairing; Defects
• CPC Class Codes: G02F 1/136263 Line defects

Abstract

An active-matrix addressing LCD panel is provided, in which a bypass can be readily formed for a broken one of the source/drain bus lines without degrading any display characteristic and without increasing the number of man-hour. A TFT-array substrate of the panel has gate bus lines and source/drain bus lines extending perpendicular to each other, pixel areas defined by the gate and source/drain bus lines, TFTs formed near respective intersections of the gate and source/drain bus lines in the corresponding pixel areas, pixel electrodes formed in the respective pixel areas, and light-shielding layers formed in the respective pixel areas. Each of the source/drain bus lines is overlapped with a corresponding one of the light-shielding layers at first and second locations. The first and second locations are defined in such a way that a bypass for each of the source/drain bus lines is formed by electrically connecting each of the source/drain bus lines to the corresponding one of the light-shielding layers at the associated first and second locations.

Claims

1. An LCD panel including a TFT-array substrate, said TFT-array substrate comprising:

a plate made of a substantially flat transparent dielectric material;

gate bus lines formed in a first conductive patterned layer on said plate to extend along a first direction;

source/drain bus lines formed in a second conductive patterned layer on said plate to extend along a second direction substantially perpendicular to said first direction;

a plurality of pixel areas formed on said plate;

a plurality of TFTs formed near respective intersections of said gate bus line and said source/drain bus lines, each TFT contacting the adjacent one of the plurality of pixel areas, the adjacent gate bus line and the adjacent source/drain bus line;

a plurality of pixel electrodes formed in a third conductive patterned layer disposed over the pixel areas;

light-shielding layers formed in said first conductive patterned layer in a region proximate to said pixel areas, the light-shielding layers not electrically connected to the pixel electrodes;

each of said TFTs having a gate electrode electrically connected to one of said gate bus lines, one of a pair of source/drain electrodes electrically connected to one of said source/drain bus lines and another one of the pair connected to one of said pixel electrodes, respectively;

each of said source/drain bus lines having at least one region which is disposed to overlap at least a part of one of said light-shielding layers at least at first and second locations;

said first and second locations being defined in such a way that a bypass for a portion of each of said source/drain bus lines is formed by electrically connecting each of said source/drain bus lines to corresponding ones of said light-shielding layers at said first and second locations.

2. An LCD panel as claimed in claim 1, wherein each of said source/drain bus lines has first and second extensions proximate to each adjacent one of said pixel areas;

and wherein said first and second extensions of each of said source/drain bus lines are formed to laterally extend from a same side of said source/drain bus lines to have at least one overlap region with one of said light-shielding layers.

3. An LCD panel as claimed in claim 1, wherein each of said light-shielding layers is coupled to first and second protruding parts;

and wherein said first and second protruding parts are formed to laterally extend from a same side of a corresponding one of said source/drain bus lines to be at least partially overlapped with at least one of said light-shielding layers;

and wherein said first and second locations are positioned in said first and second protruding parts, respectively.

4. An LCD panel as claimed in claim 3, wherein further each adjacent two individual ones of said light-shielding layers are physically connected to each other below a corresponding one of said source/drain bus lines so as to form a single light-shielding layer disposed adjacent to two pixel areas, and said source/drain bus line does not have the first and second lateral extensions, and the first and second locations are positioned on the source/drain bus line.

5. A repair method of an LCD panel including a TFT-array substrate, comprising:

said TFT-array substrate having a plate made of a substantially flat transparent dielectric material, gate bus lines formed in a first conductive patterned layer on said plate to extend along a first direction, source/drain bus lines formed in a second conductive patterned layer on said plate to extend along a second direction substantially perpendicular to said first direction, pixel areas formed on said substantially flat transparent plate, TFTs formed near respective intersections of said gate bus line and said source/drain bus lines in said corresponding pixel areas, pixel electrodes formed in a third conductive patterned layer in said respective pixel areas, and light-shielding layers formed in said first conductive patterned layer in a region proximate to said respective pixel areas, the light-shielding layers not electrically connected to the pixel electrodes;

each of said TFTs having a gate electrode electrically connected to a corresponding one of said gate bus lines, a pair of source/drain electrodes electrically connected to a corresponding one of said source/drain bus lines and a corresponding one of said pixel electrodes, respectively;

each of said source/drain bus lines having an overlapped region with at least a part of a corresponding one of said light-shielding layers at first and second locations;

said first and second locations being defined in such a way that a bypass for a portion of each of said source/drain bus lines is formed by electrically connecting each of said source/drain bus lines to corresponding ones of said light-shielding layers at said overlapped first and second locations;

said repair method further comprising;

a step of irradiating a laser beam to said first and second locations of a broken one of said source/drain bus and a corresponding one of said light-shielding layers, thereby forming an electrical bypass for said broken one of said source/drain bus lines with the use of said corresponding one of said light-shielding layer.

6. A repair method as claimed in claim 5, wherein said laser beam irradiates said first and second location through said substantially flat transparent plate of said TFT-array substrate.