LCD having auxiliary capacitance lines and light shielding films electrically connected via contact holes

• US 6,556,265 B1
• Filed: 11/15/1999
• Issued: 04/29/2003
• Est. Priority Date: 03/19/1998
• 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
• Assistant Examiner(s): SCHECHTER, ANDREW M
• Application Number:
  US09/423,818
• Time in Patent Office: 1,261 Days
• Field of Search: 349/38, 349/39, 349/110, 349/111, 349/160
• US Class Current: 349/111
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 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: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence

Abstract

With a liquid crystal device of a type wherein light-shielding films are provided below TFTs, in order to enable high-quality image display with a relatively simple configuration using the light-shielding film and capacitance lines, the liquid crystal device may consist of a liquid crystal layer held between a pair of substrates, and pixel electrodes provided in a matrix on a TFT array substrate. A plurality of light-shielding films formed of metal with a high melting point and divided into strips are formed below the pixel TFTs, scanning lines, capacitance lines, and so forth, and the capacitance lines and light-shielding films are electrically connected via contact holes. The resistance of the capacitance lines is lowered by the light-shielding films.

Claims

1. A liquid crystal device, comprising:

a pair of substrates including a first substrate and a second substrate;

a plurality of pixel electrodes arrayed in a matrix on said second substrate;

a liquid crystal held between said pair of substrates;

a plurality of thin film transistors, each transistor connected to in correspondence with said pixel electrodes;

a plurality of data lines and plurality of scanning lines;

a plurality of capacitance lines arrayed along with said plurality of scanning lines, each capacitance line extending in a direction intersecting with said plurality of data lines and providing a storage capacitor to said plurality of pixel electrodes;

a plurality of light-shielding films, each light-shielding film extending in a direction intersecting with said plurality of data lines, and being provided at positions covering at least a channel area of said plurality of thin film transistors when viewed from a second substrate side and at least partially facing said plurality of capacitance lines, each light-shielding film being electrically connected to said plurality of capacitance lines for every pixel or plurality of pixels in a direction intersecting to said plurality of data lines; and

a first inter-layer insulating film provided between said capacitance lines and said plurality of light-shielding films, wherein

said plurality of capacitance lines and said plurality of light-shielding films are each electrically connected via contact holes opened in said first-interlayer insulating film at positions overlapping said data lines on a plane.

2. The liquid crystal device according to claim 1, each of said plurality of light-shielding films being formed facing said scanning lines only at positions covering said channel area.

3. The liquid crystal device according to claim 1, said capacitance lines and said scanning lines being formed of one conductive thin film;

and

said capacitance lines serving as a first storage capacitor electrode and a second storage capacitor electrode extending from a semiconductor layer comprising one of a source area and a drain area of a thin film transistor side connected to said pixel electrode being provided with said storage capacitor by being opposingly positioned with a dielectric film which is formed of a gate insulating film forming said thin film transistor being introduced therebetween.

4. The liquid crystal device according to claim 3, each of said plurality of light-shielding films being opposingly positioned as a third storage capacitor electrode at an opposite side of said second storage capacitor electrode with said first storage capacitor electrode and said first inter-layer insulating film introduced therebetween.

5. The liquid crystal device according to claim 1, said contact holes having a circular planar form parallel to said second substrate.

6. The liquid crystal device according to claim 1, each of said plurality of light-insulating films having a planar form parallel to said second substrate including a first area formed parallel to said scanning lines and a second area extended from said first area parallel to said data lines, with said contact holes being opened in said second area.

7. The liquid crystal device according to claim 1, said capacitance lines and said plurality of light-shielding films being connected to a constant potential source.

8. The liquid crystal device according to claim 7, said constant potential source being a constant potential source supplied to peripheral circuit for driving said liquid crystal device.

9. The liquid crystal device according to claim 7, further comprising an opposite electrode formed on said first substrate substrate;

and

said constant potential source being a constant potential source supplied to said opposite electrode.

10. The liquid crystal device according to claim 1, each of said plurality of light-shielding films being electrically connected to said capacitance lines of its own tier.

11. The liquid crystal device according to claim 1, said plurality of light-shielding films including at least one of Ti, Cr, W, Ta, Mo, and Pb.

12. A liquid crystal device, comprising:

a pair of substrates including a first substrate and a second substrate;

a plurality of pixel electrodes arrayed in a matrix on said second substrate;

a liquid crystal held between said pair of substrates;

a plurality of thin film transistors, each transistor connected to said plurality of pixel electrodes;

a plurality of data lines and plurality of scanning lines mutually intersecting;

a plurality of capacitance lines arrayed along with said plurality of scanning lines, each capacitance line extending in a direction intersecting with said plurality of data lines and providing a storage capacitor to said plurality of pixel electrodes;

a plurality of light-shielding films, each light-shielding film extending in a direction intersecting with said plurality of data lines, and provided at positions covering at least a channel area of said-plurality of thin film transistors when viewed from a second substrate side and at least partially facing said plurality of scanning lines, each light-shielding film being electrically connected to said plurality of capacitance lines for every pixel or plurality of pixels in a direction intersecting to said plurality of data lines; and

a first inter-layer insulating film provided between said plurality of capacitance lines and said plurality of light-shielding films, wherein

said plurality of capacitance lines and said plurality of light-shielding films are each electrically connected via contact holes opened in said first-interlayer insulating film at positions overlapping said plurality of data lines on a plane.

13. A liquid crystal device, comprising:

a pair of substrates including a first substrate and a second substrate;

a plurality of pixel electrodes arrayed in a matrix on said second substrate;

a liquid crystal held between said pair of substrates;

a plurality of thin film transistors, each transistor connected to said plurality of pixel electrodes;

a plurality of data lines and plurality of scanning lines;

a plurality of capacitance lines arrayed along with said plurality of scanning lines, each capacitance line extending in a direction intersecting with said plurality of data lines and providing a storage capacitor to said plurality of pixel electrodes;

a plurality of light-shielding films, each light-shielding film extending in a direction intersecting with said plurality of data lines, and being provided at positions covering at least a channel area of said plurality of thin film transistors when viewed from a second substrate side and at least partially facing said plurality of capacitance lines, wherein the light-shielding films are electrically connected to said capacitance lines of neighboring tiers.

14. A liquid crystal device, comprising:

a pair of substrates including a first substrate and a second substrate;

a plurality of pixel electrodes arrayed in a matrix on said second substrate;

a liquid crystal held between said pair of substrates;

a plurality of thin film transistors, each transistor connected to said plurality of pixel electrodes;

a plurality of data lines and plurality of scanning lines;

a plurality of capacitance lines arrayed along with said plurality of scanning lines, each capacitance line extending in a direction intersecting with said plurality of data lines and providing a storage capacitor to said plurality of pixel electrodes;

a plurality of light-shielding films, each light-shielding film extending in a direction intersecting with said plurality of data lines, and being provided at positions covering at least a channel area of said plurality of thin film transistors when viewed from a second substrate side and at least partially facing said plurality of capacitance lines, each light-shielding film being electrically connected to said plurality of capacitance lines for every pixel or plurality of pixels in a direction intersecting to said plurality of data lines; and

a first inter-layer insulating film provided between said plurality of light-shielding films and said thin-film transistors

a second inter-layer insulating film provided above said scanning lines and below said data lines, and

a third inter-layer insulating film provided above said data lines and below said pixel electrodes, a side of said third inter-layer insulating film which faces said liquid crystal being flattened by at least one of said first inter-layer insulating film, said second inter-layer insulating film, and said third inter-layer insulating film recessed at least portions facing said data lines.

15. A projection-type display apparatus comprising a light source, a liquid crystal light valve that modulates incident light cast from said light source according to image information, and a projecting device that projects the light modulated by said liquid crystal light valve,

said liquid crystal light valve having a liquid crystal device in which a liquid crystal is held between a first substrate positioned on a light incident side and a second substrate positioned on a light outgoing side, a first polarizing element positioned at an outward side of said first substrate, and a second polarizing element positioned at an outward side of said second substrate, said projection-type display apparatus further comprising upon said second substrate:

a plurality of pixel electrodes arrayed in a matrix;

a plurality of thin film transistors, each transistor connected to said plurality of pixel electrodes;

a plurality of data lines and plurality of scanning lines mutually intersecting;

a plurality of capacitance lines arrayed along with said plurality of scanning lines, each capacitance line extending in a direction intersecting with said plurality of data lines and providing a storage capacitor to said plurality of pixel electrodes;

a plurality of light-shielding films, each light-shielding film extending in a direction intersecting with said plurality of data lines, and provided at positions covering at least a channel area of said plurality of thin film transistors when viewed from a second substrate side and at least partially facing said plurality of capacitance lines, each light-shielding film being electrically connected to said plurality of capacitance lines for every pixel or plurality of pixels in a direction intersecting with said plurality of data lines; and

a first inter-layer insulating film provided between said plurality of capacitance lines and said plurality of light-shielding films, wherein

said plurality of capacitance lines and said plurality of light-shielding films are each electrically connected via contact holes opened in said first-interlayer insulating film at positions overlapping said plurality of data lines on a plane.

16. A liquid crystal device, comprising:

a pair of substrates including a first substrate and a second substrate;

a plurality of pixel electrodes arrayed in a matrix on said second substrate;

a liquid crystal held between said pair of substrates;

a plurality of thin film transistors, each transistor connected to said plurality of pixel electrodes;

a plurality of data lines and plurality of scanning lines mutually intersecting;

a plurality of storage capacitors connected to said plurality of pixel electrodes;

light-shielding films provided at positions covering at least a channel area of said plurality of thin film transistors when viewed from a second substrate side, each light-shielding film being electrically connected to said plurality of storage capacitors;

a first inter-layer insulating film provided between said light-shielding films and said thin-film transistors;

a second inter-layer insulating film provided above said scanning lines and below said data lines, and

a third inter-layer insulating film provided above said data lines and below said pixel electrodes, a third inter-layer insulating film side which faces said liquid crystal being flattened by at least one of said first inter-layer insulating film, said second inter-layer insulating film, and said third inter-layer insulating film recessed at portions facing at least one of said thin film transistors, said data lines, said scanning lines, and said storage capacitors.

17. A liquid crystal device, comprising:

a pair of substrates including a first substrate and a second substrate;

a plurality of pixel electrodes arrayed in a matrix on said second substrate;

a liquid crystal held between said pair of substrates;

a plurality of thin film transistors, each transistor connected to said plurality of pixel electrodes;

a plurality of data lines and plurality of scanning lines mutually intersecting;

a plurality of capacitor lines serving as a first storage capacitor electrode;

a plurality of second storage capacitor electrodes connected to said plurality of pixel electrodes;

light-shielding films provided at positions covering at least a channel area of said plurality of thin film transistors when viewed from a second substrate side, each light-shielding film being electrically connected to said plurality of capacitor lines; and

wherein said light-shielding films are provided in an island-like manner at positions so as to overlap at least one of said plurality of scanning lines and said plurality of capacitor lines when viewed from a second substrate side, and each of the plurality of the island-shaped portions arrayed parallel to said scanning lines are electrically connected via said plurality of capacitor lines.

18. The liquid crystal device according to claim 17, said capacitance and said scanning lines being formed of one conductive thin film;

and

said first storage capacitor electrodes and said second storage capacitor electrodes extending from a semiconductor layer comprising one of a source area and a drain area of a thin film transistor connected to said pixel electrode comprising a storage capacitor by being opposingly positioned with a dielectric film which is formed of a gate insulating film forming said thin film transistor being introduced therebetween.

19. The liquid crystal device according to claim 17, said first inter-layer insulating film being introduced between said capacitance lines and said light-shielding films;

and

said capacitance lines and said light-shielding films each being connected via contact holes opened in said first inter-layer insulating film.

20. The liquid crystal device according to claim 19, said contact holes being opened for each pixel.

21. The liquid crystal device according to claim 19, said contact holes being opened for each pixel group formed of a plurality of pixels.

22. The liquid crystal device according to claim 19, said contact holes being opened below said data lines when viewed from a first substrate side.

23. The liquid crystal device according to claim 17, said capacitance lines and said light-shielding films being connected to a constant potential source.

24. The liquid crystal device according to claim 23, said constant potential source being a constant potential source supplied to a peripheral circuit for driving said liquid crystal device.

25. The liquid crystal device according to claims 23, further comprising an opposite electrode formed on the second substrate,

said constant potential source being a constant potential source supplied to said opposite electrode.

26. The liquid crystal device according to claim 19, said capacitance lines including wiring portions, each wiring portion being formed parallel to said plurality of scanning lines;

and

said light-shielding films being formed parallel to said scanning lines so as to each appear overlapped when a capacitance line portion is viewed from a second substrate side.

27. The liquid crystal device according to claim 17, said light-shielding films being provided in a screen-like manner at positions so as to each appear overlapped with at least one of said plurality of scanning lines and said plurality of capacitance lines, and said plurality of data lines when viewed from a second substrate side.

28. The liquid crystal device according to claim 17, said light-shielding films being provided in strips at positions so as to appear overlapped with at least one of said plurality of scanning lines and said plurality of capacitance lines when viewed from a second substrate side.

29. The liquid crystal device according to claim 17, said light-shielding films including at least one of Ti, Cr, W, Ta, Mo, and Pb.

30. An electronic equipment, comprising the liquid crystal device according to claim 17.