LCD having a particular light-shield and connection

• US 6,704,068 B2
• Filed: 02/27/2001
• Issued: 03/09/2004
• Est. Priority Date: 02/27/1997
• 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): Ton, Toan
• Application Number:
  US09/793,147
• Publication Number:
  US 20010030722A1
• Time in Patent Office: 1,106 Days
• Field of Search: 349/44, 349/110, 349/111, 349/38, 349/149, 349/150, 349/151, 349/152, 257/59, 257/72
• US Class Current: 349/44
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• 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
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: H01L 29/78633 with a light shield
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells

Abstract

A leak current due to the effect of light reflected by a polarizing plate or the like is suppressed in pixel switching TFTs in a liquid crystal device and a projection type display device comprising the liquid crystal device, and the characteristics of pixel switching TFT are stabilized. In a liquid crystal device substrate of a liquid crystal device, a first light shielding film is provided below at least the channel region of pixel switching TFTs, extending along scanning lines and connected to constant potential wiring for supplying a constant potential on an outside of the pixel region to fix the potential of the first light shielding film.

Claims

1. A liquid crystal device comprising:

a liquid crystal device substrate including a display region in which pixels are formed in a matrix by a plurality of data lines and a plurality of scanning lines, a peripheral circuit connected to at least one of the data lines and the scanning lines on an outer peripheral side of the display region, and a plurality of thin film transistors connected to the data lines and the scanning lines, and a liquid crystal held between the liquid crystal device substrate and an opposite substrate; and

a plurality of conductive first light shielding films for shielding respective channel regions of the thin film transistors formed below at least the respective channel regions of the thin film transistors so as to extend along at least one signal line of the scanning line and the data line;

wherein the peripheral circuit includes a conductive film made of at least one of the conductive first light shielding films as a wiring.

2. The liquid crystal device according to claim 1, wherein the peripheral circuit includes a multistage shift register circuit, and a connecting wiring between the shift register circuit in the present stage and the shift register circuit in a succeeding stage is the wiring.

3. The liquid crystal device according to claim 2, wherein the shift register circuit is formed by a plurality of transistors adjacent to each other, and the wiring is formed in a lower region than a semiconductor layer of the transistors and between the transistors.

4. The liquid crystal device according claim 2, wherein the shift register circuit includes a plurality of transmission gate circuits, and the conductive film made of the wiring is formed in a lower region than a semiconductor layer comprising the transmission gate circuits and between the transmission gate circuits.

5. The liquid crystal device according to claim 1, wherein the wiring is connected to a source electrode of the transistor.

6. The liquid crystal device according to claim 1, wherein the peripheral circuit includes a complementary transistor, and the wiring is positioned below the channel region of each of the transistors which comprises the complementary transistor, and each of the wiring is connected to the source electrode of each of the transistors which comprises the complementary transistor.

7. The liquid crystal device according to claim 1, wherein the peripheral circuit includes a transistor, and the conductive film made of the conductive first light shielding film overlapping with a gate electrode is positioned below the transistor, and the wiring is electrically connected to the gate electrode.

8. The liquid crystal device according to claim 1, wherein the peripheral circuit is an inverter circuit.

9. The liquid crystal device according to claim 8, wherein a wiring on the input side of the inverter circuit is a conductive filmmade of the data lines.

10. A liquid crystal device comprising:

a liquid crystal device substrate including a display region in which pixels are formed in a matrix by a plurality of data lines and a plurality of scanning lines, a peripheral circuit connected to at least one of the data lines and the scanning lines on an outer peripheral side of the display region, and a plurality of thin film transistors connected to the data lines and the scanning lines, and a liquid crystal held between the liquid crystal device substrate and an opposite substrate; and

a plurality of conductive first light shielding films for shielding respective channel regions of the thin film transistors formed below at least the respective channel regions of the thin film transistors so as to extend along at least one signal line of the scanning line and the data line;

wherein the peripheral circuit includes a transistor, and a conductive film made of at least one of the conductive first light shielding films overlapping at least the channel region is positioned below the transistor.