Display device

• US 7,369,143 B2
• Filed: 10/20/2003
• Issued: 05/06/2008
• Est. Priority Date: 10/21/2002
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koyama, Jun
• Primary Examiner(s): DHARIA, PRABODH M
• Application Number:
  US10/687,742
• Publication Number:
  US 20040080501A1
• Time in Patent Office: 1,660 Days
• Field of Search: 345/691, 345211-214, 345 76-100, 345/204, 345/205, 345/103, 359/630, 315/169.3, 323/282, 363/59, 349/155, 349/158, 427/66, 25037009-37011
• US Class Current: 345/691
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters

Abstract

A display device according to the present invention includes a switching regulator control circuit formed of TFTs. A digital switching regulator control circuit is composed of an AD converter circuit, a CPU, a pulse generation circuit or the like. An analog switching regulator control circuit is composed of an error amplifier circuit, a triangle wave generation circuit, a PWM comparator or the like. By integrally forming the switching regulator control circuit on a display device, the problem of the conventional portable information equipment as to the reduction in size and weight can be solved.

Claims

1. A display device comprising:

a pixel portion comprising a first thin film transistor; and

a switching regulator comprising;

a switching regulator control circuit comprising a second thin film transistor;

a switching element driven according to an output signal from said switching regulator control circuit to raise or lower a voltage; and

a capacitor electrically connected to the switching element,

wherein the switching regulator control circuit is electrically connected to the capacitor

wherein the first thin film transistor and the second thin film transistor are formed over a first substrate, and

wherein the switching element is packed over a second substrate.

2. A display device according to claim 1, wherein a plurality of switching regulator control circuits are formed over the substrate.

3. A display device according to claim 1, wherein said display device is a liquid crystal display device.

4. A display device according to claim 1, wherein said display device is an EL display device.

5. A display device according to claim 1, wherein the display device is applied to electronic equipment selected from the group consisting of a digital camera, a notebook type personal computer, a PDA, a DVD player, a folding portable display device, a watch type display device and a mobile telephone.

6. A display device according to claim 1, wherein an FPC is used as the second substrate.

7. A display device comprising:

a pixel portion comprising a first thin film transistor; and

a switching regulator comprising;

a switching regulator control circuit comprising a second thin film transistor;

a switching element driven according to an output signal from said switching regulator control circuit to raise or lower a voltage; and

a capacitor electrically connected to the switching element,

wherein the switching regulator control circuit is electrically connected to the capacitor,

wherein the first thin film transistor and the second thin film transistor are formed over a first substrate, and

wherein the switching element and the capacitor are packed over a second substrate.

8. A display device according to claim 7, wherein a plurality of switching regulator control circuits are formed over the substrate.

9. A display device according to claim 7, wherein said display device is a liquid crystal display device.

10. A display device according to claim 7, wherein said display device is an EL display device.

11. A display device according to claim 7, wherein the display device is applied to electronic equipment selected from the group consisting of a digital camera, a notebook type personal computer, a PDA, a DVD player, a folding portable display device, a watch type display device and a mobile telephone.

12. A display device according to claim 7, wherein an FPC is used as the second substrate.

13. A display device comprising:

a pixel portion comprising a first thin film transistor; and

a switching regulator comprising;

a switching regulator control circuit comprising a second thin film transistor;

a switching element;

an inductor;

a diode; and

a smoothing capacitor electrically connected to the switching element,

wherein said switching regulator control circuit comprises;

a voltage feed back circuit electrically connected to the smoothing capacitor; and

a duty control circuit which controls a switching duty of said switching element, wherein the first thin film transistor and the second thin film transistor are formed over a first substrate, and

wherein the switching element is packed over a second substrate.

14. A display device according to claim 13, wherein said inductor, said diode, and said smoothing capacitor are packed over said second substrate.

15. A display device according to claim 13, wherein said switching element is made up of a thin film transistor.

16. A display device according to claim 13, wherein a plurality of switching regulator control circuits are formed over the substrate.

17. A display device according to claim 13, wherein said display device is a liquid crystal display device.

18. A display device according to claim 13, wherein said display device is an EL display device.

19. A display device according to claim 13, wherein the display device is applied to electronic equipment selected from the group consisting of a digital camera, a notebook type personal computer, a PDA, a DVD player, a folding portable display device, a watch type display device and a mobile telephone.

20. A display device according to claim 13, wherein an FPC is used as the second substrate.

21. A display device comprising:

a pixel portion comprising a first thin film transistor over a substrate; and

a switching regulator comprising;

a switching regulator control circuit comprising a second thin film transistor formed over the substrate;

a switching element driven according to an output signal from said switching regulator control circuit to raise or lower a voltage; and

a capacitor electrically connected to the switching element,

wherein the switching regulator control circuit is electrically connected to the capacitor,

wherein the first thin film transistor and the second thin film transistor are formed over a first substrate,

wherein the switching element is packed over a second substrate, and

wherein said switching regulator control circuit uses an analog signal.

22. A display device according to claim 21, wherein said switching regulator control circuit comprises a reference voltage source, an error amplifier circuit, a triangle wave generation circuit, and a PWM comparator.

23. A display device according to claim 21, wherein a plurality of switching regulator control circuits are formed over the substrate.

24. A display device according to claim 21, wherein said display device is a liquid crystal display device.

25. A display device according to claim 21, wherein said display device is an EL display device.

26. A display device according to claim 21, wherein the display device is applied to electronic equipment selected from the group consisting of a digital camera, a notebook type personal computer, a PDA, a DVD player, a folding portable display device, a watch type display device and a mobile telephone.

27. A display device according to claim 21, wherein an FPC is used as the second substrate.

28. A display device comprising:

a pixel portion comprising a first thin film transistor over a substrate; and

a switching regulator comprising;

a switching regulator control circuit comprising a second thin film transistor formed over the substrate;

a switching element driven according to an output signal from said switching regulator control circuit to raise or lower a voltage; and

a capacitor electrically connected to the switching element,

wherein the switching regulator control circuit is electrically connected to the capacitor,

wherein the first thin film transistor and the second thin film transistor are formed over a first substrate,

wherein the switching element is packed over a second substrate, and

wherein said switching regulator control circuit uses a digital signal.

29. A display device according to claim 28, wherein said switching regulator control circuit comprises an AD converter circuit, a nonvolatile memory, a CPU, and a pulse generation circuit.

30. A display device according to claim 28, wherein a plurality of switching regulator control circuits are formed over the substrate.

31. A display device according to claim 28, wherein said display device is a liquid crystal display device.

32. A display device according to claim 28, wherein said display device is an EL display device.

33. A display device according to claim 28, wherein the display device is applied to electronic equipment selected from the group consisting of a digital camera, a notebook type personal computer, a PDA, a DVD player, a folding portable display device, a watch type display device and a mobile telephone.

34. A display device according to claim 28, wherein an FPC is used as the second substrate.