Light shielding structure of a substrate for a liquid crystal device, liquid crystal device and projection type display device

• US 6,388,721 B1
• Filed: 04/05/2001
• Issued: 05/14/2002
• Est. Priority Date: 10/16/1996
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Murade, Masao
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): CHOWDHURY, TARIFUR RASHID
• Application Number:
  US09/825,843
• Publication Number:
  US 20020024622A1
• Time in Patent Office: 404 Days
• Field of Search: 349/43, 349/44, 349/95, 349/110, 349/111, 257/59, 257/72
• 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

Placement of a first light shielding film (7) at least below the channel region (1c) of a TFT which drives a pixel, and of a second light shielding film (3) above the same prevents impingement of light coming from above or from below on that channel region (1c). Further, a second light shielding film (3) is formed to cover the channel region (1c) and the first light shielding film (7), thereby to prevent the surface of the first light shielding film (7) from direct exposure to light.

Claims

1. A liquid crystal device, comprising:

a first substrate;

a second substrate;

a plurality of data lines formed above the first substrate;

a plurality of scan lines crossing the plurality of data lines;

a plurality of thin film transistors connected to the plurality of data lines and the plurality of scan lines;

a plurality of pixel electrodes connected to the plurality of thin film transistors;

a first light shielding film extending along the scan lines, formed at least below a channel region of the thin film transistors, and below junctions between the channel region and a source region and between the channel region and a drain region of the thin film transistors; and

a second light shielding film formed above the channel region and the junctions between the channel region and the source region and between the channel region and the drain region,

a width of the second light shielding film being more than a width of the first light shielding film.

2. The liquid crystal device as described in claim 1, the thin film transistor having a semiconductor layer which intersects twice the scan line.

3. The liquid crystal device as described in claim 2, the second light shielding film is formed below at least one region of the semiconductor layer intersecting twice with the scan line.

4. The liquid crystal device as described in claim 3, the second light shielding film is the data line.

5. The liquid crystal device as described in claim 2, the first light shielding film being formed below at least one region of the semiconductor layer intersecting twice with the scan line.

6. The liquid crystal device as described in claim 1, further comprising a contact hole connecting a semiconductor layer of the thin film transistor and the data line.

7. The liquid crystal device as described in claim 6, the semiconductor layer having a region that extends from the contact hole along the data line, intersecting the scan line.

8. A liquid crystal device, comprising:

a first substrate;

a second substrate;

a plurality of data lines formed above the first substrate;

a plurality of scan lines crossing the plurality of data lines;

a plurality of thin film transistors connected to the plurality of data lines and the plurality of scan lines;

a plurality of pixel electrodes connected to the plurality of thin film transistors;

a first light shielding film extending along the data lines, formed at least below a channel region of the thin film transistors, and below junctions between the channel region and a source region and between the channel region and a drain region of the thin film transistors; and

a second light shielding film formed above the channel region and the junctions between the channel region and the source region and between the channel region and the drain region,

a width of the second light shielding film being more than a width of the first light shielding film.

9. The liquid crystal device as described in claim 8, the second light shielding film is the data line.