EL display device, driving method thereof, and electronic equipment provided with the EL display device

• US 8,830,146 B2
• Filed: 09/19/2013
• Issued: 09/09/2014
• Est. Priority Date: 06/21/1999
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Fukunaga, Takeshi, Yamauchi, Yukio
• Primary Examiner(s): VO, TUYET THI
• Application Number:
  US14/031,088
• Publication Number:
  US 20140015872A1
• Time in Patent Office: 355 Days
• Field of Search: 345/92, 345/90, 345/76, 345/77, 345/80, 345/87, 345/102, 313/506, 313/504, 313/498, 313/500, 313/503, 313/509
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2300/04 Structural and physical details of display devices
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0417 Special arrangements specific to the use of low carrier mobility technology
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 3/2018 by time modulation using two or more time intervals
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/30 using electroluminescent panels
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: H01L 27/1277 using a crystallisation promoting species, e.g. local introduction of Ni catalyst
• CPC Class Codes: H01L 27/1296 adapted to increase the uniformity of device parameters
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/0603 characterised by particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions isolation regions between components H01L21/76; design considerations for integrated circuits H01L27/00; geometrical design considerations for devices H01L29/0657
• CPC Class Codes: H01L 29/786 Thin film transistors, i.e. transistors with a channel being at least partly a thin film transistors having only the source or the drain region on an insulator layer H01L29/0653; thin film FinFETs H01L29/785
• CPC Class Codes: H01L 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78624 the source and the drain regions being asymmetrical
• CPC Class Codes: H01L 29/78627 : with a significant overlap between the lightly doped drain and the gate electrode, e.g. GOLDD
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/62 : Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
• CPC Class Codes: H10K 2102/3026 : Top emission
• CPC Class Codes: H10K 50/87 : Arrangements for heating or cooling
• CPC Class Codes: H10K 59/12 : Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/1213 : the pixel elements being TFTs
• CPC Class Codes: H10K 59/122 : Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/8794 : Arrangements for heating and cooling

Abstract

An EL display device capable of performing clear multi-gradation color display and electronic equipment provided with the EL display device are provided, wherein gradation display is performed according to a time-division driving method in which the luminescence and non-luminescence of an EL element (109) disposed in a pixel (104) are controlled by time, and the influence by the characteristic variability of a current controlling TFT (108) is prevented. When this method is used, a data signal side driving circuit (102) and a gate signal side driving circuit (103) are formed with TFTs that use a silicon film having a peculiar crystal structure and exhibit an extremely high operation speed.

Claims

1. A light-emitting device comprising:

a pixel over a substrate, the pixel comprising;

a first transistor;

an electroluminescence element electrically connected to the first transistor; and

a wiring electrically connected to the first transistor, the wiring being configured to supply current to the electroluminescence element through the first transistor,

wherein the electroluminescence element comprises;

a pixel electrode over and electrically connected to the first transistor, the pixel electrode overlapping with a channel formation region of the first transistor;

an electroluminescence layer over the pixel electrode; and

a conductive film over the electroluminescence layer, the conductive film being configured to transmit light which is generated when the current flows between the pixel electrode and the conductive film.

2. The light-emitting device according to claim 1,

wherein the pixel further comprises a source wiring and a second transistor which is electrically connected to the source wiring and the first transistor, and

wherein the pixel electrode does not overlap with the channel formation region of the second transistor.

3. The light-emitting device according to claim 1,

wherein the pixel further comprises a second transistor which is electrically connected to the first transistor, and

wherein the second transistor has two channel formation regions which are connected in series.

4. The light-emitting device according to claim 1,

wherein the pixel further comprises an insulating layer which covers an edge portion of the pixel electrode,

wherein the electroluminescence layer overlaps with the insulating layer, and

wherein the insulating layer has a tapered shape in a region which overlaps with the edge portion.

5. The light-emitting device according to claim 1,

wherein the channel formation region comprises polysilicon.

6. The light-emitting device according to claim 1,

wherein the pixel further comprises a passivation film over the conductive film.

7. The light-emitting device according to claim 6,

wherein a thickness of the passivation film ranges from 10 nm to 1 μ

m.

8. The light-emitting device according to claim 6,

wherein a thickness of the passivation film ranges from 200 nm to 500 nm.

9. An electronic device comprising:

a module comprising;

a substrate;

a pixel portion over the substrate, the pixel portion comprising a plurality of pixels;

a first driver circuit over the substrate, the first driver circuit being configured to control emission of the plurality of pixels; and

a flexible printed circuit electrically connected to the first driver circuit,

wherein the plurality of pixels each comprises;

a first transistor;

an electroluminescence element electrically connected to the first transistor; and

a wiring electrically connected to the first transistor, the wiring being configured to supply current to the electroluminescence element through the first transistor,

wherein the electroluminescence element comprises;

a pixel electrode over and electrically connected to the first transistor, the pixel electrode overlapping with a channel formation region of the first transistor;

an electroluminescence layer over the pixel electrode; and

a conductive film over the electroluminescence layer, the conductive film being configured to transmit light which is generated when the current flows between the pixel electrode and the conductive film.

10. The electronic device according to claim 9,

wherein the plurality of pixels each further comprises a source wiring and a second transistor which is electrically connected to the source wiring and the first transistor, and

wherein the pixel electrode does not overlap with the channel formation region of the second transistor.

11. The electronic device according to claim 9,

wherein the plurality of pixels each further comprises a second transistor which is electrically connected to the first transistor, and

wherein the second transistor has two channel formation regions which are connected in series.

12. The electronic device according to claim 9,

wherein the plurality of pixels each further comprises an insulating layer which covers an edge portion of the pixel electrode,

wherein the electroluminescence layer overlaps with the insulating layer, and

wherein the insulating layer has a tapered shape in a region which overlaps with the edge portion.

13. The electronic device according to claim 9,

wherein the channel formation region comprises polysilicon.

14. The electronic device according to claim 9,

wherein the module further comprises a second driving circuit configured to control the emission of the plurality of pixels, and

wherein the second driving circuit is formulated into an IC chip.

15. The electronic device according to claim 9,

wherein the plurality of pixels includes a red pixel, a blue pixel, and a green pixel.

16. An electronic device comprising:

a display portion;

a switch for operating the electronic device;

a voice inputting portion;

an image reception portion; and

a battery,

wherein the display portion comprises a module which comprises;

a substrate;

a pixel portion over the substrate, the pixel portion comprising a plurality of pixels;

a first driver circuit over the substrate, the first driver circuit being configured to control emission of the plurality of pixels; and

a flexible printed circuit electrically connected to the first driver circuit,

wherein the plurality of pixels each comprises;

a first transistor;

an electroluminescence element electrically connected to the first transistor; and

a wiring electrically connected to the first transistor, the wiring being configured to supply current to the electroluminescence element through the first transistor,

wherein the electroluminescence element comprises;

a pixel electrode over and electrically connected to the first transistor, the pixel electrode overlapping with a channel formation region of the first transistor;

an electroluminescence layer over the pixel electrode; and

a conductive film over the electroluminescence layer, the conductive film being configured to transmit light which is generated when the current flows between the pixel electrode and the conductive film.

17. The electronic device according to claim 16,

wherein the plurality of pixels each further comprises a source wiring and a second transistor which is electrically connected to the source wiring and the first transistor, and

wherein the pixel electrode does not overlap with the channel formation region of the second transistor.

18. The electronic device according to claim 16,

wherein the plurality of pixels each further comprises a second transistor which is electrically connected to the first transistor, and

wherein the second transistor has two channel formation regions which are connected in series.

19. The electronic device according to claim 16,

wherein the plurality of pixels each further comprises an insulating layer which covers an edge portion of the pixel electrode,

wherein the electroluminescence layer overlaps with the insulating layer, and

wherein the insulating layer has a tapered shape in a region which overlaps with the edge portion.

20. The electronic device according to claim 16,

wherein the channel formation region comprises polysilicon.

21. The electronic device according to claim 16,

wherein the module further comprises a second driving circuit configured to control the emission of the plurality of pixels, and

wherein the second driving circuit is formulated into an IC chip.

22. The electronic device according to claim 16,

wherein the plurality of pixels includes a red pixel, a blue pixel, and a green pixel.