Projection television set

• US 7,425,743 B2
• Filed: 03/28/2005
• Issued: 09/16/2008
• Est. Priority Date: 02/25/1998
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ohtani, Hisashi, Hayakawa, Masahiko, Yamazaki, Shunpei
• Primary Examiner(s): NGO, NGAN V
• Application Number:
  US11/090,287
• Publication Number:
  US 20050194594A1
• Time in Patent Office: 1,268 Days
• Field of Search: 257/59, 257/72, 257/350, 257/E27.131, 257/E27.132, 257/E27.134, 257/E29.151
• US Class Current: 257/350
• 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 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 27/1277 using a crystallisation promoting species, e.g. local introduction of Ni catalyst
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/66765 Lateral single gate single channel transistors with inverted structure, i.e. the channel layer is formed after the gate
• CPC Class Codes: H01L 29/78675 with normal-type structure, e.g. with top gate
• CPC Class Codes: H01L 29/78678 with inverted-type structure, e.g. with bottom gate

Abstract

Thin-film transistors constituting a liquid crystal module have a channel forming region that is a crystal structural body in which a plurality of rod-like or flat-rod-like crystals are arranged in a particular direction. In the thin-film transistors, deteriorations in device characteristics due to hot carrier injection or the like can be prevented effectively when the temperature is in a range of 80° C.-250° C. (preferably 100° C.-200° C.). Therefore, a projection TV that is very high in reliability can be realized.

Claims

1. A projection television set comprising:

a light source, which emits a light;

(n−

1) dichroic mirrors, which divide the light into n components;

n liquid crystal panels, wherein each of the n components of the light enters a corresponding one of the n liquid crystal panels; and

a dichroic prism, by which the n components of the light are combined,

wherein each of the n liquid crystal panels comprises;

a substrate;

a pixel portion comprising;

a first thin film transistor comprising;

an active layer over the substrate;

a gate insulating layer over the active layer; and

a gate electrode over the gate insulating layer;

a capacitor element comprising;

a first electrode electrically connected to the active layer;

an insulating layer over the first electrode; and

a second electrode over the insulating layer; and

a pixel electrode electrically connected to the active layer;

a signal line electrically connected to the first thin film transistor; and

a driver portion electrically connected to the signal line, comprising a second thin film transistor over the substrate,

wherein the active layer comprises a crystalline silicon layer,

wherein the insulating layer comprises a silicon nitride, and

wherein the number n is a natural number larger than 1.

2. A projection television set according to claim 1 wherein at least a part of the second electrode overlaps the active layer.

3. A projection television set according to claim 1 wherein each of the n liquid crystal panels is a transmission-type liquid crystal panel.

4. A projection television set according to claim 1,

wherein the number n is 3, and

wherein each of a red component light, a green component light and a blue component light enters a corresponding one of the 3 liquid crystal panels.

5. A projection television set according to claim 1 wherein a temperature of the active layer is 80°

C. to 250°

C. when the projection television is operated.

21. A projection television set according to claim 1 wherein the substrate is a quartz substrate.

22. A projection television set according to claim 1 wherein the first thin film transistor is a full depletion type thin film transistor.

23. A projection television set according to claim 1 wherein the second thin film transistor is a full depletion type thin film transistor.

6. A projection television set comprising:

a light source, which emits a light;

(n−

1) dichroic mirrors, which divide the light into n components;

n liquid crystal panels, wherein each of the n components of the light enters a corresponding one of the n liquid crystal panels; and

a dichroic prism, by which the n components of the light are combined,

wherein each of the n liquid crystal panels comprises;

a substrate;

a pixel portion comprising;

a first thin film transistor comprising;

a first active layer over the substrate;

a first gate insulating layer over the first active layer; and

a first gate electrode over the gate insulating layer;

a capacitor element comprising;

a first electrode electrically connected to the first active layer;

an insulating layer over the first electrode; and

a second electrode over the insulating layer; and

a pixel electrode electrically connected to the first active layer;

a signal line electrically connected to the first thin film transistor; and

a driver portion electrically connected to the signal line, comprising a second thin film transistor comprising;

a second active layer over the substrate;

a second gate insulating layer over the second active layer; and

a second gate electrode over the second gate insulating layer;

wherein each of the first active layer and second active layer comprises a crystalline silicon layer,

wherein the insulating layer comprises a silicon nitride, and

wherein the number n is a natural number larger than 1.

7. A projection television set according to claim 6 wherein at least a part of the second electrode overlaps the first active layer.

8. A projection television set according to claim 6 wherein each of the n liquid crystal panels is a transmission-type liquid crystal panel.

9. A projection television set according to claim 6,

wherein the number n is 3, and

wherein each of a red component light, a green component light and a blue component light enters a corresponding one of the 3 liquid crystal panels.

10. A projection television set according to claim 6 wherein a temperature of the first active layer is 80°

C. to 250°

C. when the projection television is operated.

24. A projection television set according to claim 6, wherein the substrate is a quartz substrate.

25. A projection television set according to claim 6, wherein the first thin film transistor is a full depletion type thin film transistor.

26. A projection television set according to claim 6, wherein the second thin film transistor is a full depletion type thin film transistor.

11. A projection television set comprising:

a light source, which emits a light;

(n−

1) dichroic mirrors, which divide the light into n components;

n liquid crystal panels, wherein each of the n components of the light enters a corresponding one of the n liquid crystal panels; and

a dichroic prism, by which the n components of the light are combined,

wherein each of the n liquid crystal panels comprises;

a substrate;

a pixel portion comprising;

a first thin film transistor comprising;

an active layer over the substrate;

a gate insulating layer over the active layer; and

a gate electrode over the gate insulating layer;

a capacitor element comprising;

a first electrode electrically connected to the active layer;

an insulating layer over the first electrode; and

a second electrode over the insulating layer; and

a pixel electrode electrically connected to the active layer;

a signal line electrically connected to the first thin film transistor; and

a driver portion electrically connected to the signal line, comprising a second thin film transistor over the substrate,

wherein the active layer comprises a crystalline silicon layer,

wherein the insulating layer comprises a silicon nitride

wherein the active layer has a channel forming region and a low-concentration impurity region adjacent to the channel forming region, and

wherein the number n is a natural number larger than 1.

12. A projection television set according to claim 11 wherein at least a part of the second electrode overlaps the active layer.

13. A projection television set according to claim 11 wherein each of the n liquid crystal panels is a transmission-type liquid crystal panel.

14. A projection television set according to claim 11,

wherein the number n is 3, and

wherein each of a red component light, a green component light and a blue component light enters a corresponding one of the 3 liquid crystal panels.

15. A projection television set according to claim 11 wherein a temperature of the active layer is 80°

C. to 250°

C. when the projection television is operated.

27. A projection television set according to claim 11 wherein the substrate is a quartz substrate.

28. A projection television set according to claim 11 wherein the first thin film transistor is a full depletion type thin film transistor.

29. A projection television set according to claim 11, wherein the second thin film transistor is a full depletion type thin film transistor.

16. A projection television set comprising:

a light source, which emits a light;

(n−

1) dichroic mirrors, which divide the light into n components;

n liquid crystal panels, wherein each of the n components of the light enters a corresponding one of the n liquid crystal panels; and

a dichroic prism, by which the n components of the light are combined,

wherein each of the n liquid crystal panels comprises;

a substrate;

a pixel portion comprising;

a first thin film transistor comprising;

a first active layer over the substrate;

a first gate insulating layer over the first active layer; and

a first gate electrode over the gate insulating layer;

a capacitor element comprising;

a first electrode electrically connected to the first active layer;

an insulating layer over the first electrode; and

a second electrode over the insulating layer; and

a pixel electrode electrically connected to the first active layer;

a signal line electrically connected to the first thin film transistor; and

a driver portion electrically connected to the signal line, comprising a second thin film transistor comprising;

a second active layer over the substrate;

a second gate insulating layer over the second active layer; and

a second gate electrode over the second gate insulating layer;

wherein each of the first active layer and second active layer comprises a crystalline silicon layer,

wherein the insulating layer comprises a silicon nitride,

wherein each of the first active layer and the second active layer has a channel forming region and a low-concentration impurity region adjacent to the channel forming region, and

wherein the number n is a natural number larger than 1.

17. A projection television set according to claim 16 wherein at least a part of the second electrode overlaps the first active layer.

18. A projection television set according to claim 16 wherein each of the n liquid crystal panels is a transmission-type liquid crystal panel.

19. A projection television set according to claim 16,

wherein the number n is 3, and

wherein each of a red component light, a green component light and a blue component light enters a corresponding one of the 3 liquid crystal panels.

20. A projection television set according to claim 16 wherein a temperature of the first active layer is 80°

C. to 250°

C. when the projection television is operated.

30. A projection television set according to claim 16, wherein the substrate is a quartz substrate.

31. A projection television set according to claim 16, wherein the first thin film transistor is a full depletion type thin film transistor.

32. A projection television set according to claim 16, wherein the second thin film transistor is a full depletion type thin film transistor.