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US 8,541,804 B2Granted
Electro-optical device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorHajime Kimura
Life of this patent
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Abstract
An object of the present invention is to realize a numerical aperture higher than that of a pixel having a conventional construction by using a pixel circuit having a novel construction in an electro-optical device. Therefore, it is utilized that the electric potential of a gate signal line in a row except for an i-th row is set to a constant electric potential in a period except for when a gate signal line (106) in the i-th row is selected. A gate signal line 111 in an (i−1)-th row is also used as an electric current supply line for an EL element (103) controlled by the gate signal line (106) in the i-th row. Thus, wiring number is reduced and high numerical aperture is realized.
Claims27
A display device comprising:
- a first pixel comprising:
- a first transistor;
- a second transistor;
- a capacitor;
- an electro luminescence element comprising a white light emitting layer;
- and
- a color filter provided corresponding to the electro luminescence element,
- wherein a gate of the first transistor is electrically connected to a first wiring,
- wherein one of a source and a drain of the first transistor is electrically connected to a gate electrode of the second transistor,
- wherein the other of the source and the drain of the first transistor is electrically connected to a second wiring through a connecting electrode,
- wherein one of a source and a drain of the second transistor is electrically connected to the electro luminescence element,
- wherein the other of the source and the drain of the second transistor is electrically connected to a third wiring,
- wherein a first terminal of the capacitor is electrically connected to the gate of the second transistor,
- wherein the first wiring, the third wiring and the connecting electrode are formed on a same layer,
- wherein the second wiring and the first wiring partially overlap with each other, and
- wherein the second wiring and the third wiring partially overlap with each other.
13 more elements
A display device comprising:
- a first pixel comprising:
- a first transistor comprising a first channel formation region;
- a second transistor comprising a second channel formation region;
- a capacitor;
- and
- an electro luminescence element,
- wherein a gate of the first transistor is electrically connected to a first wiring,
- wherein one of a source and a drain of the first transistor is electrically connected to a gate of the second transistor,
- wherein the other of the source and the drain of the first transistor is electrically connected to a second wiring through a connecting electrode,
- wherein one of a source and a drain of the second transistor is electrically connected to the electro luminescence element,
- wherein the other of the source and the drain of the second transistor is electrically connected to a third wiring,
- wherein a first terminal of the capacitor is electrically connected to the gate of the second transistor,
- wherein the first wiring, the third wiring and the connecting electrode are formed on a same layer,
- wherein the second wiring and the first wiring partially overlap with each other,
- wherein the second wiring and the third wiring partially overlap with each other,
- wherein a first polycrystal silicon film over the first channel formation region functions as the gate of the first transistor, and
- wherein a second polycrystal silicon film over the second channel formation region functions as the gate of the second transistor.
14 more elements
A display device comprising:
- a first pixel comprising:
- a first transistor comprising a first channel formation region;
- a second transistor comprising a second channel formation region;
- a capacitor;
- an electro luminescence element comprising a white light emitting layer;
- and
- a color filter provided corresponding to the electro luminescence element,
- wherein a gate of the first transistor is electrically connected to a first wiring,
- wherein one of a source and a drain of the first transistor is electrically connected to a gate of the second transistor,
- wherein the other of the source and the drain of the first transistor is electrically connected to a second wiring through a connecting electrode,
- wherein one of a source and a drain of the second transistor is electrically connected to the electro luminescence element,
- wherein the other of the source and the drain of the second transistor is electrically connected to a third wiring,
- wherein a first terminal of the capacitor is electrically connected to the gate of the second transistor,
- wherein the first wiring, the third wiring and the connecting electrode are formed on a same layer,
- wherein the second wiring and the first wiring partially overlap with each other,
- wherein the second wiring and the third wiring partially overlap with each other,
- wherein a first polycrystal silicon film over the first channel formation region functions as the gate of the first transistor,
- wherein a second polycrystal silicon film over the second channel formation region functions as the gate of the second transistor,
- wherein each of the first wiring, the third wiring and the connecting electrode comprises a first conductive film comprising Ti, a second conductive film comprising Al over the first conductive film and a third conductive film comprising Ti,
- wherein a cathode electrode of the electro luminescence element comprises Mg and Ag, and
- wherein a silicon nitride film is formed over the cathode electrode of the electro luminescence element.
18 more elements
Dependencies are inferred from the claim text.