Electronic device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorKazutaka Inukai
Life of this patent
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Abstract
To provide an electronic device capable of suppressing a luminous amount of an EL element and realizing a large number of gray-scale levels. The electronic device is characterized in that the luminescence of the EL element is controlled by a pair of EL driver TFTs, one of the pair of EL driver TFTs is controlled by one of the pair of switching TFTs and one of the pair of eliminating TFTs, the other of the pair of EL driver TFTs is controlled by the other of the pair of switching TFTs and the other of the eliminating TFTs, and gray-scale display is performed by controlling the luminescence time of the EL elements.
Claims49
An electronic device comprising:
- a pair of source signal line driver circuits;
- a pair of gate signal line driver circuits;
- and
- a pixel portion including a plurality of pixels,
- wherein said plurality of pixels each have an EL element, a pair of EL driver TFTs, a pair of switching TFTs and a pair of eliminating TFTs,
- wherein luminescence of the EL element is controlled by said pair of EL driver TFTs;
- wherein one of said pair of EL driver TFTs is controlled by one of said pair of switching TFTs and one of said pair of eliminating TFTs;
- wherein the other of said pair of EL driver TFTs is controlled by the other of said pair of switching TFTs and the other of said eliminating TFTs;
- and
- wherein gray-scale display is performed by controlling luminescence time of said plurality of EL elements.
An electronic device comprising:
- first and second source signal line driver circuits;
- first and second gate signal line driver circuits;
- a pixel portion including a plurality of pixels;
- a plurality of first source signal lines connected to said first source signal line driver circuit;
- a plurality of second source signal lines connected to said second source signal line driver circuit;
- a plurality of first gate signal lines connected to said first gate signal line driver circuit;
- a plurality of second gate signal lines connected to said second gate signal line driver circuit;
- and
- a power supply line,
- wherein said plurality of pixels each have a first switching TFT, a second switching TFT, a first eliminating TFT, a second eliminating TFT, a first EL driver TFT, a EL second driver TFT, and an EL element;
- wherein a gate electrode of said first switching TFT is connected to said first gate signal line,
- wherein a gate electrode of said second switching TFT is connected to said second gate signal line,
- wherein one of a source region and a drain region of said first switching TFT is connected to said first source signal line, and the other thereof is connected to a gate electrode of said first EL driver TFT,
- wherein one of a source region and a drain region of said second switching TFT is connected to said second source signal line, and the other thereof is connected to a gate electrode of said second EL driver TFT,
- wherein a gate electrode of said first eliminating TFT is connected to said first gate signal line,
- wherein a gate electrode of said second eliminating TFT is connected to said second gate signal line,
- wherein one of a source region and a drain region of said first eliminating TFT is connected to said power supply line, and the other thereof is connected to said gate electrode of said second EL driver TFT,
- wherein one of a source region and a drain region of said second eliminating TFT is connected to said power supply line, and the other thereof is connected to said gate electrode of said first EL driver TFT,
- wherein one of a source region and a drain region of said first EL driver TFT is connected to said power supply line, and the other thereof is connected to said EL element, respectively, and
- wherein one of a source region and a drain region of said second EL driver TFT is connected to said power supply line,and the other thereof is connected to said EL element, respectively.
A method for driving an electronic device comprising first and second gate signal line driver circuits and first and second source signal line driver circuits, and a display portion comprising a plurality of pixels, said method comprising steps of:
- inputting first digital data into the display portion by using said first gate signal line driver circuit and said first source signal line driver circuit in a first writing-in period;
- and
- inputting first digital data into the display portion by using said second gate signal line driver circuit and said second source signal line driver circuit in a second writing-in period,
- wherein said first writing-in period and said second writing-in period partially overlap each other.
A method for driving an electronic device comprising first and second gate signal line driver circuits and first and second source signal line driver circuits, and a display portion comprising a plurality of pixels, said method comprising steps of;
- inputting first digital data into the display portion by using said first gate signal line driver circuit and said first source signal line driver circuit in a first writing-in period;
- and
- inputting first digital data into the display portion by using said second gate signal line driver circuit and said second source signal line driver circuit in a second writing-in period,
- wherein each of display periods (Tr1 to Trn) is determined by time difference between the moment at which one of writing-in periods (Ta1 to Tan) begins and the moment at which the next writing-in period begins.
A display device comprising:
- a pair of source signal line driver circuits;
- a pair of gate signal line driver circuits;
- and
- a pixel portion including a plurality of pixels,
- wherein each of said plurality of pixels comprises a light emitting element, a pair of driver TFTs, a pair of switching TFTs and a pair of eliminating TFTs,
- wherein luminescence of the light emitting element is controlled by said pair of driver TFTs,
- wherein one of said pair of driver TFTs is controlled by one of said pair of switching TFTs and one of said pair of eliminating TFTs, and
- wherein the other of said pair of driver TFTs is controlled by the other of said pair of switching TFTs and the other of said eliminating TFTs.
Dependencies are inferred from the claim text.