Black matrix coupled to common electrode through a transparent conductive film

• US 5,929,948 A
• Filed: 02/19/1997
• Issued: 07/27/1999
• Est. Priority Date: 02/20/1996
• Status: Expired due to Term

• Current Assignee: Sharp Electronics Corporation (Hon Hai Precision Industry Co., Ltd.), Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Suzawa, Hideomi, Takei, Michiko, Zhang, Hongyong, Ohori, Tatsuya, Yamaguchi, Naoaki
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Horney, Kari M.
• Application Number:
  US08/808,949
• Time in Patent Office: 888 Days
• Field of Search: 349/44, 349/149, 349/110, 349/111, 349/139, 349/143, 349/43
• US Class Current: 349/44
• CPC Class Codes: G02F 1/136209 Light shielding layers, e.g. black matrix, incorporated in the active matrix substrate, e.g. structurally associated with the switching element

Abstract

An active matrix liquid crystal display comprising a common electrode (#217), connected to a conductive black matrix (#302 and #303) through a coupling electrode (#227), which allows the black matrix to be set at the common potential. The common electrode is formed on the same layer as that of the source lines and data lines. The pixel electrode (#228) and the coupling electrode (#227) are comprised of the same transparent electrically conductive material.

Claims

1. An active matrix liquid crystal display device comprising at least a pixel electrode and a black matrix, and a transparent conductive film electrode connected to said black matrix to apply a common potential thereto from external source, wherein said electrode comprises a transparent conductive layer which is the same layer as the pixel electrode.

2. An active matrix liquid crystal display device comprising at least a black matrix, a source line and a common electrode connected to said black matrix to give a common potential thereto, wherein said common electrode connected to said black matrix is formed from a same layer as said source line.

3. An active matrix device comprising:

a substrate;

a plurality of gate lines formed over said substrate;

a plurality of data lines formed over said substrate in an orthogonal relation with said plurality of gate lines to define a plurality of pixels at intersections thereof;

a plurality of pixel electrodes comprising a transparent conductive matrix provided at said plurality of pixels;

a plurality of thin film transistors connected to said pixel electrodes, respectively, each of said thin film transistors having at least a gate electrode, source, drain and channel regions where the gate electrode is connected to one of the gate lines, and the source region is connected to one of the data lines; and

a black matrix comprising a metallic material and formed over said substrate to define a periphery of said pixel electrodes,

wherein said black matrix is given an electrically fixed potential by a common electrode which is formed from a same layer as the data lines.

4. An active matrix device according to claim 3 wherein said black matrix is given said electrically fixed potential by a coupling electrode comprising the same material as said transparent conductive material.

5. An active matrix device according to claim 3 wherein the drain region of the transistors is electrically connected to the associated pixel electrodes via a conductive material which is the same material as a material of said black matrix.

6. An active matrix device comprising:

a substrate;

a plurality of gate lines formed over said substrate;

a plurality of data lines formed over said substrate in an orthogonal relation with said plurality of gate lines to define a plurality of pixels at intersections thereof;

a plurality of pixel electrodes comprising a transparent conductive matrix provided at said plurality of pixels;

a plurality of thin film transistors connected to said pixel electrodes, respectively, each of said thin film transistors having at least a gate electrode, source, drain and channel regions where the gate electrode is connected to one of the gate lines, and the source region is connected to one of the data lines;

a black matrix comprising a metallic material is formed over said substrate to define a periphery of said pixel electrodes; and

an electrode comprising the same material as said transparent conductive material coupled to said black matrix, and providing an electrically fixed potential to said black matrix.