Electronic device and driving method

• US 20020011799A1
• Filed: 04/03/2001
• Published: 01/31/2002
• Est. Priority Date: 04/06/2000
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kimura, Hajime
• Granted Patent: US 6,528,950 B2
• Time in Patent Office: Days
• US Class Current: 315/169.3
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0465 Improved aperture ratio, e.g. by size reduction of the pixel circuit, e.g. for improving the pixel density or the maximum displayable luminance or brightness
• CPC Class Codes: G09G 2300/0809 Several active elements per pixel in active matrix panels
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2320/0204 Compensation of DC component across the pixels in flat panels
• CPC Class Codes: G09G 2320/0209 Crosstalk reduction, i.e. to reduce direct or indirect influences of signals directed to a certain pixel of the displayed image on other pixels of said image, inclusive of influences affecting pixels in different frames or fields or sub-images which constitute a same image, e.g. left and right images of a stereoscopic display
• CPC Class Codes: G09G 2320/0214 with crosstalk due to leakage current of pixel switch in active matrix panels
• CPC Class Codes: G09G 2320/0223 Compensation for problems related to R-C delay and attenuation in electrodes of matrix panels, e.g. in gate electrodes or on-substrate video signal electrodes
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/30 using electroluminescent panels
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element
• CPC Class Codes: H10K 50/8426 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 50/8428 Vertical spacers, e.g. arranged between the sealing arrangement and the OLED
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 50/846 comprising getter material or desiccants
• CPC Class Codes: H10K 59/12 : Active-matrix OLED [AMOLED] displays

Abstract

An electro-optical device is provided having a pixel portion with a novel structure, and in which display irregularities such as crosstalk, which develop due to a drop in voltage caused by the wiring resistance of electric current supply lines in an electro-optical device, are improved upon. Attention is drawn to the fact that during a period in which write in of a signal to a pixel from a signal line is not performed, a signal is not input to a source signal line and to a gate signal line, but are at a fixed electric potential. An electric current supply line and a source signal line, or an electric current supply line and a gate signal line, are connected through a switching transistor. A signal is input to a connection control line during a sustain period, and the connection transistor is made conductive. The source signal line or the gate signal line is therefore utilized as a pathway for supplying electric current to the EL element.

Claims

1. An electronic device having a source signal line side driver circuit, a gate signal line side driver circuit, and a pixel portion comprising;

a plurality of source signal lines;

a plurality of gate signal lines, each of said plurality of gate signal lines intersecting said plurality of said source signal lines;

a plurality of electric current supply lines;

a plurality of connection control lines

a plurality of pixels, each of said plurality of pixels comprising a switching TFT, an EL driving TFT, an EL element and first or second connection transistor;

wherein a gate electrode of said switching TFT is electrically connected to one of said plurality of gate signal lines, one of impunity regions of said switching TFT is electrically connected to one of said plurality of said source signal lines and another one of said impurity regions of siad switching TFT is electrically connected to a gate electrode of said EL driving TFT,

wherein one of impurity regions of said EL driving TFT is electrically connected to one of said plurality of electric current supply lines and another one of said impurity regions of said EL driving TFT is electrically connected to said EL element,

wherein a gate electrode of said first connecting transistor is electrically connected to one of said plurality of connection control lines, one of impurity regions of said first connecting transistor is electrically connected to one of said source signal lines and another one of said impurity regions of said first connecting transistor is electrically connected to one of said plurality of eclectic current supply lines,

wherein a gate electrode of said second connecting transistor is electrically connected to one of said plurality of connection control lines, one of impurity regions of said second connecting transistor is electrically connected to one of said plurality of gate signal lines and another one of said impurity regions of second connecting transistor is electrically connected to one of said plurality of electric current supply lines.

8. An electronic device according to claim 1, wherein:

the polarity of an EL driver transistor is p-channel type when one of a source region and a drain region of the EL driver transistor is electrically connected to an anode of the EL element; and

the polarity of an EL driver transistor is n-channel type when one of the source region and the drain region of the EL driver transistor is electrically connected to a cathode of the EL element.

15. An electronic device according to claim 1, wherein:

the polarity of a switching transistor is identical to the polarity of the EL driver transistor.

22. An electronic device according to claim 1, wherein:

the gate signal lines are composed of aluminum, or of a material having aluminum as its main constituent.

32. An electronic device according to claim 1 wherein said electronic device is selected from the group consisting of an EL display, a video camera, a head mounted display, a DVD player, a personal computer, a portable telephone, a car audio system.

2. An electronic device comprising a source signal line side driver circuit, a gate signal line side driver circuit, and a pixel portion;

wherein;

the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of electric current supply lines, a connection control line, and a plurality of pixels;

each of the plurality of pixels has an EL element and a connection transistor;

a gate electrode of the connection transistor is electrically connected to the connection control line; and

one of a source region and a drain region of the connection transistor is electrically connected to any one of the plurality of source signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of electric current control lines.

9. An electronic device according to claim 2, wherein:

the polarity of an EL driver transistor is p-channel type when one of a source region and a drain region of the EL driver transistor is electrically connected to an anode of the EL element; and

the polarity of an EL driver transistor is n-channel type when one of the source region and the drain region of the EL driver transistor is electrically connected to a cathode of the EL element.

16. An electronic device according to claim 2, wherein:

the polarity of a switching transistor is identical to the polarity of the EL driver transistor.

23. An electronic device according to claim 2, wherein:

the gate signal lines are composed of aluminum, or of a material having aluminum as its main constituent.

33. An electronic device according to claim 2 wherein said electronic device is selected from the group consisting of an EL display, a video camera, a head mounted display, a DVD player, a personal computer, a portable telephone, a car audio system.

3. An electronic device comprising a source signal line side driver circuit, a gate signal line side driver circuit, and a pixel portion;

wherein;

the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of electric current supply lines, a connection control line, and a plurality of pixels;

each of the plurality of pixels has an EL element and a connection transistor;

a gate electrode of the connection transistor is electrically connected to the connection control line; and

one of a source region and a drain region of the connection transistor is electrically connected to any one of the plurality of gate signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of electric current control lines.

10. An electronic device according to claim 3, wherein:

the polarity of an EL driver transistor is p-channel type when one of a source region and a drain region of the EL driver transistor is electrically connected to an anode of the EL element; and

the polarity of an EL driver transistor is n-channel type when one of the source region and the drain region of the EL driver transistor is electrically connected to a cathode of the EL element.

17. An electronic device according to claim 3, wherein:

the polarity of a switching transistor is identical to the polarity of the EL driver transistor.

24. An electronic device according to claim 3, wherein:

the gate signal lines are composed of aluminum, or of a material having aluminum as its main constituent.

34. An electronic device according to claim 3 wherein said electronic device is selected from the group consisting of an EL display, a video camera, a head mounted display, a DVD player, a personal computer, a portable telephone, a car audio system.

4. An electronic device comprising a source signal line side driver circuit, a gate signal line side driver circuit, and a pixel portion;

wherein;

the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of electric current supply lines, a connection control line, and a plurality of pixels;

each of the plurality of pixels has an EL element, a first connection transistor, and a second connection transistor;

a gate electrode of the first connection transistor is electrically connected to the connection control line;

one of a source region and a drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of electric current supply lines;

a gate electrode of the second connection transistor is electrically connected to the connection control line; and

one of a source region and a drain region of the second connection transistor is electrically connected to any one of the plurality of gate signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of electric current supply lines.

11. An electronic device according to claim 4, wherein:

the polarity of an EL driver transistor is p-channel type when one of a source region and a drain region of the EL driver transistor is electrically connected to an anode of the EL element; and

the polarity of an EL driver transistor is n-channel type when one of the source region and the drain region of the EL driver transistor is electrically connected to a cathode of the EL element.

18. An electronic device according to claim 4, wherein:

the polarity of a switching transistor is identical to the polarity of the EL driver transistor.

25. An electronic device according to claim 4, wherein:

the gate signal lines are composed of aluminum, or of a material having aluminum as its main constituent.

35. An electronic device according to claim 4 wherein said electronic device is selected from the group consisting of an EL display, a video camera, a head mounted display, a DVD player, a personal computer, a portable telephone, a car audio system.

5. An electronic device comprising a source signal line side driver circuit, a gate signal line side driver circuit, and a pixel portion;

wherein;

the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of electric current supply lines, a connection control line, and a plurality of pixels;

each of the plurality of pixels has an EL element, a first connection transistor, and a second connection transistor;

a gate electrode of the first connection transistor is electrically connected to the connection control line;

one of a source region and a drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of electric current supply lines;

a gate electrode of the second connection transistor is electrically connected to the connection control line; and

one of a source region and a drain region of the second connection transistor is electrically connected to any one of the plurality of source signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of gate signal lines.

12. An electronic device according to claim 5, wherein:

the polarity of an EL driver transistor is p-channel type when one of a source region and a drain region of the EL driver transistor is electrically connected to an anode of the EL element; and

the polarity of an EL driver transistor is n-channel type when one of the source region and the drain region of the EL driver transistor is electrically connected to a cathode of the EL element.

19. An electronic device according to claim 5, wherein:

the polarity of a switching transistor is identical to the polarity of the EL driver transistor.

26. An electronic device according to claim 5, wherein:

the gate signal lines are composed of aluminum, or of a material having aluminum as its main constituent.

36. An electronic device according to claim 5 wherein said electronic device is selected from the group consisting of an EL display, a video camera, a head mounted display, a DVD player, a personal computer, a portable telephone, a car audio system.

6. An electronic device comprising a source signal line side driver circuit, a gate signal line side driver circuit, and a pixel portion;

wherein;

the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of electric current supply lines, a connection control line, and a plurality of pixels;

each of the plurality of pixels has an EL element, a first connection transistor, and a second connection transistor;

a gate electrode of the first connection transistor is electrically connected to the connection control line;

one of a source region and a drain region of the first connection transistor is electrically connected to any one of the plurality of gate signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of electric current supply lines;

a gate electrode of the second connection transistor is electrically connected to the connection control line; and

one of a source region and a drain region of the second connection transistor is electrically connected to any one of the plurality of source signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of gate signal lines.

13. An electronic device according to claim 6, wherein:

the polarity of an EL driver transistor is p-channel type when one of a source region and a drain region of the EL driver transistor is electrically connected to an anode of the EL element; and

the polarity of an EL driver transistor is n-channel type when one of the source region and the drain region of the EL driver transistor is electrically connected to a cathode of the EL element.

20. An electronic device according to claim 6, wherein:

the polarity of a switching transistor is identical to the polarity of the EL driver transistor.

27. An electronic device according to claim 6, wherein:

the gate signal lines are composed of aluminum, or of a material having aluminum as its main constituent.

37. An electronic device according to claim 6 wherein said electronic device is selected from the group consisting of an EL display, a video camera, a head mounted display, a DVD player, a personal computer, a portable telephone, a car audio system.

7. An electronic device comprising a source signal line side driver circuit, a gate signal line side driver circuit, and a pixel portion;

wherein;

the pixel portion has a plurality of source signal lines, a plurality of gate signal lines, a plurality of electric current supply lines, a connection control line, and a plurality of pixels;

each of the plurality of pixels has an EL element, a first connection transistor, a second connection transistor, and a third connection transistor;

a gate electrode of the first connection transistor is electrically connected to the connection control line;

one of a source region and a drain region of the first connection transistor is electrically connected to any one of the plurality of source signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of electric current supply lines;

a gate electrode of the second connection transistor is electrically connected to the connection control line;

one of a source region and a drain region of the second connection transistor is electrically connected to any one of the plurality of gate signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of electric current supply lines;

a gate electrode of the third connection transistor is electrically connected to the connection control line; and

one of a source region and a drain region of the third connection transistor is electrically connected to any one of the plurality of source signal lines, and the other one of the source region and the drain region is electrically connected to any one of the plurality of gate signal lines.

14. An electronic device according to claim 7, wherein:

the polarity of an EL driver transistor is p-channel type when one of a source region and a drain region of the EL driver transistor is electrically connected to an anode of the EL element; and

the polarity of an EL driver transistor is n-channel type when one of the source region and the drain region of the EL driver transistor is electrically connected to a cathode of the EL element.

21. An electronic device according to claim 7, wherein:

the polarity of a switching transistor is identical to the polarity of the EL driver transistor.

28. An electronic device according to claim 7, wherein:

the gate signal lines are composed of aluminum, or of a material having aluminum as its main constituent.

38. An electronic device according to claim 7 wherein said electronic device is selected from the group consisting of an EL display, a video camera, a head mounted display, a DVD player, a personal computer, a portable telephone, a car audio system.

29. A method of driving an electronic device, comprising n-bit gray scale control by controlling the length of time during which an EL element is turned on, wherein:

a first connection transistor or a second connection transistor is conductive during the sustain (turn on) periods which do not overlap with the address (write in) periods; and

an electric current supply line and a source signal line electrically connected to a source region and a drain region of the first connection transistor are placed in a conducting state, or an electric current supply line and a source signal line electrically connected to a source region and a drain region of the second connection transistor are placed in a conducting state.

30. A method of driving an electronic device, comprising n-bit gray scale control by controlling the length of time during which an EL element is turned on, wherein:

the supply of electric current to the EL element during the sustain (turn on) periods which do not overlap with the address (write in) periods is performed by an electric current supply line and;

a source signal line electrically connected to the electric current supply line through a first connection transistor;

or a gate signal line electrically connected to the electric current supply line through a second connection transistor.

31. A method of driving an electronic device, comprising n-bit gray scale control by controlling the length of time during which an EL element is turned on, wherein:

an electric current supply line and a number i row gate signal line electrically connected to a source region and a drain region of a connection transistor are placed in a conducting state with the number i gate signal line is unselected.

39. An electric device having at least one electroluminesence display device comprising:

at least one gate signal line;

at least one source signal line intersected said gate signal line;

at least one EL element;

at least one electric current supply line;

a switching TFT, a gate electrode of said switching TFT electrically connected to said gate signal line and one of impurity regions of said switching TFT electrically connected to said source signal line;

an EL driving TFT, a gate electrode of siad EL driving TFT electrically connected to another one of impurity regions of said switching TFT, one of impurity regions of said EL driving TFT electrically connected to said electric current supply line and another one of impurity regions electrically connected to said EL element;

a connection transistor, a gate electrode of said connection transistor electrically connected to a connection control line, one of impurity regions of said connection transistor electrically connected to said source signal line or said gate signal line another one of impurity regions of said connection transistor electrically connected to said electric current supply line.