IP Library › Granted Patent US 7,567,227
Granted Patent B2
US 7,567,227 · App. 11/039,371 · Granted Jul 28, 2009

Electronic device and method of driving the same

Assignee: Semiconductor Energy Laboratory Co., Ltd.
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Quick Facts
Patent No.
US 7,567,227
App. No.
11/039,371
Granted
Jul 28, 2009
Kind
B2
Abstract

To provide a novel driving method for driving an electronic device by using digital gray scale and time gray scale in combination, which secures high duty ratio, which can display an image normally even when a sustain period is shorter than an address period, and which is hardly affected by dulled signal waveform. In a sub-frame period ( 102 ) where a sustain period is shorter than an address period, a clear period ( 105 ) is squeezed in between completion of a sustain period ( 104 ) and start of an address period of the subsequent sub-frame period. The length of the sustain period ( 104 ) thus can be set without being limited by the length of an address period ( 103 ). This non-display period is provided by changing the electric potential of a storage capacitor line. Therefore, unlike the case where the non-display period is provided by changing the electric potential of a cathode wiring, the present invention is hardly affected by dulled signal waveform.

Claims (44)

1. A method of driving an electronic device, with one frame period comprising n sub-frame periods SF 1 , SF 2 , . . . , SF n , the n sub-frame periods each comprising address periods Ta 1 , Ta 2 , . . . , Ta n and sustain periods Ts 1 , Ts 2 , . . . , Ts n , comprising the steps of:

inputting a first signal to a pixel comprising a light emitting element from a source signal line during each address period, wherein a capacitor storage line is maintained at a first potential;

turning on the light emitting element during each sustain period, wherein the capacitor storage line is maintained at the first potential;

providing a clear period Tc m during a period from an end of the sustain period Ts m (1≦m≦n−1) of a sub-frame period SF m through until a start of the address period Ta m+1 of a sub-frame period SF m+1 , wherein the capacitor storage line is maintained at a second potential.

2. A method of driving an electronic device as claimed in claim 1 , wherein a clear signal inputted during the clear period is provided by increasing or lowering the electric potential of a capacitor storage line by means of a signal inputted from a capacitor storage line driving circuit.

3. A method of driving an electronic device as claimed in claim 1 , wherein an EL element does not emit light during the clear period irrespective of an image signal.

4. A method of driving an electronic device, with one frame period comprising n sub-frame periods SF 1 , SF 2 , . . . , SF n , the n sub-frame periods each comprising address periods Ta 1 , Ta 2 , . . . , Ta n and sustain periods Ts 1 , Ts 2 , . . . , Ts n , comprising the steps of:

inputting a first signal to a pixel comprising a light emitting element from a source signal line during an address period Ta n of a j-th (0<j) frame sub-frame period SF n , wherein a capacitor storage line is maintained at a first potential;

turning on the light emitting element during a sustain period Ts n of a j-th (0<j) frame sub-frame period SF n , wherein a capacitor storage line is maintained at a first potential;

providing a clear period Tc n during a period from an end of the sustain period Ts n through until a start of the address period Ta 1 of a (j+1)-th period frame sub-frame period SF 1 , wherein the capacitor storage line is maintained at a second potential.

5. A method of driving an electronic device as claimed in claim 4 , wherein a clear signal inputted during the clear period is provided by increasing or lowering the electric potential of a capacitor storage line by means of a signal inputted from a capacitor storage line driving circuit.

6. A method of driving an electronic device as claimed in claim 4 , wherein an EL element does not emit light during the clear period irrespective of an image signal.

7. A method of driving an electronic device, with one frame period comprising n sub-frame periods SF 1 , SF 2 , . . . , SF n , the n sub-frame periods each comprising address periods Ta 1 , Ta 2 , . . . , Ta n and sustain periods Ts 1 , Ts 2 , . . . , Ts n ,

providing a clear period Tc k during a period from an end of the sustain period Ts k (1≦m ≦n) of a sub-frame period SF k through until a start of the address period Ta k+1 of a sub-frame period SF k+1 , wherein the capacitor storage line is maintained at a second potential.

8. A method of driving an electronic device as claimed in claim 7 , wherein a clear signal inputted during the clear period is provided by increasing or lowering the electric potential of a capacitor storage line by means of a signal inputted from a capacitor storage line driving circuit.

9. A method of driving an electronic device as claimed in claim 7 , wherein an EL element does not emit light during the clear period irrespective of an image signal.

10. An electronic device operated by a driving method in which:

one frame period comprises n sub-frame periods SF 1 , SF 2 , . . . , SF n ;

the n sub-frame periods each comprises address periods Ta 1 , Ta 2 , . . . , Ta n and sustain periods Ts 1 , Ts 2 , . . . , Ts n ;

inputting a first signal to a pixel comprising a light emitting element from a source signal line during each address period, wherein a capacitor storage line is maintained at a first potential;

turning on the light emitting element during each sustain period, wherein the capacitor storage line is maintained at the first potential;

providing a clear period Tc m during a period from an end of the sustain period Ts m (1≦m≦n−1) of a sub-frame period SF m through until a start of the address period Ta m+1 of a sub-frame period SF m+1 , wherein the capacitor storage line is maintained at a second potential.

11. An electronic device as claimed in claim 10 , wherein a clear signal inputted during the clear period is provided by increasing or lowering the electric potential of a capacitor storage line by means of a signal inputted from a capacitor storage line driving circuit.

12. An electronic device as claimed in claim 10 , wherein an EL element does not emit light during the clear period irrespective of an image signal.

13. A method of driving a electronic device according to claim 10 , wherein said electronic device is a device selected from the group consisting of: an EL display, a video camera, a head-mount display, a DVD player, a personal computer, a cellular phone and an audio system for automobiles.

14. An electronic device according to claim 10 , wherein said electronic device is a device selected from the group consisting of: an EL display, a video camera, a head-mount display, a DVD player, a personal computer, a cellular phone and an audio system for automobiles.

15. An electronic device operated by a driving method in which:

one frame period comprises n sub-frame periods SF 1 , SF 2 , . . . , SF n ;

the n sub-frame periods each comprises address periods Ta 1 , Ta 2 , . . . , Ta n and sustain (lights-on) periods Ts 1 , Ts 2 , . . . , Ts n ;

inputting a first signal to a pixel comprising a light emitting element from a source signal line during an address period Ta n of a j-th (0<j) frame sub-frame period SF n , wherein a capacitor storage line is maintained at a first potential;

turning on the light emitting element during a sustain period Ts n of a j-th (0<j) frame sub-frame period SF n , wherein a capacitor storage line is maintained at a first potential;

providing a clear period Tc n during a period from an end of the sustain period Ts n through until a start of the address period Ta 1 of a (j+1)-th period frame sub-frame period SF 1 , wherein the capacitor storage line is maintained at a second potential.

16. An electronic device as claimed in claim 15 , wherein a clear signal inputted during the clear period is provided by increasing or lowering the electric potential of a capacitor storage line by means of a signal inputted from a capacitor storage line driving circuit.

17. An electronic device as claimed in claim 15 , wherein an EL element does not emit light during the clear period irrespective of an image signal.

18. A method of driving a electronic device according to claim 15 , wherein said electronic device is a device selected from the group consisting of: an EL display, a video camera, a head-mount display, a DVD player, a personal computer, a cellular phone and an audio system for automobiles.

19. An electronic device according to claim 15 , wherein said electronic device is a device selected from the group consisting of: an EL display, a video camera, a head-mount display, a DVD player, a personal computer, a cellular phone and an audio system for automobiles.

20. An electronic device wherein:

one frame period comprises n sub-frame periods SF 1 , SF 2 , . . . , SF n ;

the n sub-frame periods each comprises address periods Ta 1 , Ta 2 , . . . , Ta n and sustain periods Ts 1 , Ts 2 , . . . , Ts n ; and,

providing a clear period Tc k during a period from an end of the sustain period Ts k (1≦k≦n) of a sub-frame period SF k through until a start of the address period Ta k+1 of a sub-frame period SF k+1 , wherein the capacitor storage line is maintained at a second potential.

21. An electronic device as claimed in claim 20 , wherein a clear signal inputted during the clear period is provided by increasing or lowering the electric potential of a capacitor storage line by means of a signal inputted from a capacitor storage line driving circuit.

22. An electronic device as claimed in claim 20 , wherein an EL element does not emit light during the clear period irrespective of an image signal.

23. A method of driving a electronic device according to claim 20 , wherein said electronic device is a device selected from the group consisting of: an EL display, a video camera, a head-mount display, a DVD player, a personal computer, a cellular phone and an audio system for automobiles.

24. An electronic device according to claim 20 , wherein said electronic device is a device selected from the group consisting of: an EL display, a video camera, a head-mount display, a DVD player, a personal computer, a cellular phone and an audio system for automobiles.

Priority Claims (1)
JP 2000-118619 · Apr 19, 2000 · national
Continuity (2)
Continuation 0983671900 · Apr 17, 2001
Related Publication 20050200576A1 · Sep 15, 2005