Liquid crystal display apparatus

• US 5,760,854 A
• Filed: 03/04/1997
• Issued: 06/02/1998
• Est. Priority Date: 07/27/1994
• Status: Expired due to Term

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Hashimoto, Kenichi, Sakuta, Hiroki, Ono, Kikuo, Suzuki, Masahiko, Nakayoshi, Yoshiaki, Tsumura, Makoto, Kaneko, Toshiki, Onisawa, Kenichi, Ogawa, Kazuhiro, Minemura, Tetsuro
• Primary Examiner(s): TRAN, MINH LOAN
• Application Number:
  US08/810,734
• Time in Patent Office: 455 Days
• Field of Search: 257/59, 257/72, 349/38, 349/39, 349/42, 349/43, 349/44
• US Class Current: 349/38
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/136218 Shield electrodes
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1259 Multistep manufacturing methods

Abstract

In order to provide a liquid crystal display apparatus having bright image display and a preferred production yield, a gate insulating film under a transparent pixel electrode on a transparent substrate is provided with an aperture smaller than a plane area of the pixel electrode, and a source electrode pattern under the pixel electrode is composed so as to cross the aperture. Thin film transistors (TFT) of the liquid crystal display apparatus have a gate electrode and a laminate layer of a gate insulating film and a semiconductor film. End portions of the gate electrode and the laminate layer are tapered, and the end portion of the gate electrode is tapered with a taper angle equal to or less than three times (where, less than 90°) of a taper angle at the end portion of the laminate layer.

Claims

1. A liquid crystal display apparatus comprising:

a first substrate,

a plurality of gate lines formed on said first substrate,

a plurality of data lines intersecting with said gate lines,

a plurality of thin film transistors formed near the intersections of said gate lines and said data lines, each thin film transistor including an insulating layer formed on said gate lines and said first substrate, and a semiconductor layer formed on said insulating layer,

a plurality of pixel electrodes electrically connected to said thin film transistors,

a shielding electrode extending in parallel to said data lines, said shielding electrode being separated and insulated from said data lines and said gate lines,

a second substrate, and

a liquid crystal between said first and second substrates;

wherein said insulating layer has an opening portion under each of said pixel electrodes, and a peripheral portion of each of said pixel electrodes and said shielding electrode is disposed to overlap with each other and is insulated from each other by said insulating layer.

4. A liquid crystal display apparatus as claimed in any one of claims 1, 2 and 3, wherein a transparent conductive film providing said pixel electrodes extends to source electrodes of said thin film transistors.

5. A liquid crystal display apparatus as claimed in any one of claims 1, 2 and 3, wherein said insulating layer is provided from a same layer as a gate insulating film of said thin film transistors.

6. A liquid crystal display apparatus as claimed in any one of claims 1, 2 and 3, wherein said shielding electrode is separated and insulated from said data lines and said semiconductor layer by said insulating layer.

7. A liquid crystal display apparatus as claimed in any one of claims 1, 2 and 3, wherein said shielding electrode is formed of a same layer as said gate lines and electrically separated from said gate lines.

8. A liquid crystal display apparatus as claimed in any one of claims 1, 2 and 3, wherein said shielding electrode is disposed to overlap with said data lines.

9. A liquid crystal display apparatus as claimed in any one of claims 1, 2 and 3, wherein said shielding electrode is disposed to cover a part of said data lines in a plane view.

10. A liquid crystal display apparatus as claimed in any one of claims 1, 2 and 3, wherein said shielding electrode is positioned spaced from said data lines.

11. A liquid crystal display apparatus as claimed in any one of claims 1, 2 and 3, further comprising:

a plurality of conductive lines in parallel with said gate lines, provided to form capacitor elements, said capacitor elements including said insulating layer sandwiched between said conductive lines and said pixel electrodes, and said shielding electrode is formed between said gate lines and said conductive lines.

2. A liquid crystal display apparatus comprising:

a first substrate,

a plurality of gate lines formed on said first substrate,

a plurality of data lines intersecting with said gate lines,

a plurality of thin film transistors formed near the intersections of said gate lines and said data lines, each thin film transistor including an insulating layer formed on said gate lines and said first substrate, and a semiconductor layer formed on said insulating layer,

a plurality of pixel electrodes electrically connected to said thin film transistors,

a shielding electrode of a stripe-shape extending in parallel to said data lines, said shielding electrode being separated and insulated from said data lines and said gate lines,

a second substrate including a transparent common electrode, and

a liquid crystal between said first and second substrates;

wherein a central portion of each of said pixel electrodes contacts with said first substrate, and a peripheral portion of each of said pixel electrodes and said shielding electrode is disposed to overlap with each other and is insulated from each other by said insulating layer.

12. A liquid crystal display apparatus as claimed in claim 2 or 3, wherein said central portion of each of said pixel electrodes contacts with an orientation film.

3. A liquid crystal display apparatus comprising:

a first substrate,

a plurality of gate lines formed on said first substrate,

a plurality of data lines intersecting with said gate lines,

a plurality of thin film transistors formed near the intersections of said gate lines and said data lines, each thin film transistor including an insulating layer formed on said gate lines and said first substrate, and a semiconductor layer formed on said insulating layer,

a plurality of pixel electrodes electrically connected to said thin film transistors,

a shielding electrode of a stripe-shape extending in parallel to said data lines, said shielding electrode being separated and insulated from said data lines and said gate lines,

a second substrate including a transparent common electrode,

an opaque shielding film having an opening portion arranged in a matrix formed on said second substrate, and

a liquid crystal between said first and second substrates;

wherein said shielding electrode and said opaque shielding film are disposed to overlap with each other, a central portion of each of said pixel electrodes contacts with said first substrate, and a peripheral portion of each of said pixel electrodes and said shielding electrode is disposed to overlap with each other and is insulated from each other by said insulating layer.

13. A liquid crystal display apparatus comprising:

a substrate,

a plurality of gate lines formed on said substrate,

a plurality of data lines intersecting with said gate lines,

a plurality of thin film transistors formed near the intersections of said gate lines and said data lines, each of the thin film transistors including an insulating layer formed on said gate lines and said first substrate, a semiconductor layer formed on said insulating layer, and a source electrode and a drain electrode formed on said semiconductor layer,

a plurality of pixel electrodes electrically connected to said thin film transistors,

a capacitor element, comprising (1) a gate line adjacent to a gate line whereon a respective thin film transistor is formed, (2) an insulating film, and (3) a pixel electrode, the insulating film being sandwiched between said pixel electrode and said gate line adjacent to the gate line whereon the respective thin film transistor is formed,

a second substrate, and

a liquid crystal between said first and second substrates;

wherein a first taper angle (TH1), of said insulating layer of said thin film transistors, is larger than a second taper angle (TH2), of said insulating film of said capacitor element.

15. A liquid crystal display apparatus as claimed in claim 13 or 14, wherein each of said pixel electrodes is constituted by a transparent conductive film extending to said source electrode by crossing over a region with said first taper angle of said insulating layer, and extending to said capacitor element by crossing over a region with said second taper angle of said insulating film.

16. A liquid crystal display apparatus as claimed in claim 15, wherein a central portion of each of said pixel electrodes contacts with said first substrate.

17. A liquid crystal display apparatus as claimed in claim 13 or 14, wherein said semiconductor layer and a conductive film of said thin film transistors have substantially a same plane pattern.

18. A liquid crystal display apparatus as claimed in claim 13 or 14, wherein said gate line is coated with an anodic oxide film of a conductive material composing said gate lines.

14. A liquid crystal display apparatus comprising:

a substrate,

a plurality of gate lines formed on said substrate,

a plurality of date lines intersecting with said gate lines,

a plurality of thin film transistors formed near the intersections of said gate lines and said data lines, each of the thin film transistors including an insulating layer formed on said gate lines and said first substrate, a semiconductor layer formed on said insulating layer, and a source electrode and a drain electrode formed on said semiconductor layer,

a plurality of pixel electrodes electrically connected to said thin film transistors,

a plurality of conductive lines in parallel with said gate lines, said conductive lines forming capacitor elements together with an insulating film and said pixel electrodes, the insulating film being sandwiched between the conductive lines and the pixel electrodes so as to provide the capacitor elements,

a second substrate, and

a liquid crystal between said first and second substrates;

wherein a first taper angle, of said insulating layer of said thin film transistors, is larger than a second taper angle, of said insulating film of said capacitor elements.