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US 7,791,571 B2Granted
Light emitting device and driving method of the same
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsHisashi Ohtani, Yoshifumi Tanada, Aya Anzai
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Abstract
The invention provides a light emitting device which can suppress the reduction of luminance in accordance with the light emission time and light emission at a high luminance. Moreover, the invention relates to a driving method which can suppress the reduction of luminance in accordance with the light emission time and light emission at a high luminance. The light emitting device of the invention can display a plurality of colors of which brightness and chromaticity are different by visually mixing light emission of a plurality of light emitting elements of which light emission colors are different. When a visually mixed display color is formed, a white light emission is exhibited.
Claims31
A driving method of a light emitting device comprising:
- applying a video signal from a source signal line to a first transistor and a second transistor through a switching transistor;
- generating a first potential difference between a first electrode and a second electrode of a first light emitting element, wherein the first electrode of the first light emitting element is connected to a first current supply line, and the second electrode of the first light emitting element is connected to a second current supply line;
- generating a second potential difference between a first electrode and a second electrode of a second light emitting element, wherein the first electrode of the second light emitting element is connected to the second current supply line, and the second electrode of the second light emitting element is connected to a third current supply line;
- sequentially making the first light emitting element connected to the first transistor emit light based on the video signal and the first potential difference;
- and
- sequentially making the second light emitting element connected to the second transistor emit light based on the video signal and the second potential difference,
- wherein the first light emitting element and the second light emitting element emit light so that mixed light by the first and the second light emitting element becomes visually white.
4 more elements
A driving method of a light emitting device comprising:
- applying a video signal from a source signal line to a first transistor and a second transistor through a switching transistor;
- generating a first potential difference between a first electrode and a second electrode of a first light emitting element, wherein the first electrode of the first light emitting element is connected to a first current supply line, and the second electrode of the first light emitting element is connected to a second current supply line;
- generating a second potential difference between a first electrode and a second electrode of a second light emitting element, wherein the first electrode of the second light emitting element is connected to the second current supply line, and the second electrode of the second light emitting element is connected to a third current supply line;
- sequentially making the first light emitting element connected to the first transistor emit light based on the video signal and the first potential difference;
- and
- sequentially making the second light emitting element connected to the second transistor emit light based on the video signal and the second potential difference,
- wherein the first light emitting element emits white light.
4 more elements
A light emitting device comprising:
- a source signal line;
- a first current supply line;
- a second current supply line;
- a first transistor;
- a second transistor;
- a first light emitting element;
- and
- a second light emitting element,
- wherein a gate electrode of the first transistor and a gate electrode of the second transistor are electrically connected to the source signal line through a switching transistor,
- wherein a first electrode of the first transistor is electrically connected to the first current supply line, and a second electrode of the first transistor is directly connected to a first electrode of the first light emitting element,
- wherein a first electrode of the second transistor is electrically connected to the second current supply line, and a second electrode of the second transistor is directly connected to a second electrode of the first light emitting element and an electrode of the second light emitting element,
- wherein the first light emitting element and the second light emitting element are connected in series, and wherein the first light emitting element emits white light.
9 more elements
A light emitting device comprising:
- a source signal line;
- a first current supply line;
- a second current supply line;
- a first transistor;
- a second transistor;
- a first light emitting element;
- and
- a second light emitting element,
- wherein a gate electrode of the first transistor and a gate electrode of the second transistor are electrically connected to the source signal line through a switching transistor,
- wherein a first electrode of the first transistor is electrically connected to the first current supply line, and a second electrode of the first transistor is directly connected to one electrode of the first light emitting element,
- wherein a first electrode of the second transistor is electrically connected to the second current supply line, and a second electrode of the second transistor is directly connected to the second electrode of the first light emitting element and an electrode of the second light emitting element,
- wherein the first light emitting element and the second light emitting element are connected in series, and
- wherein the first light emitting element and the second light emitting element emit light so that mixed light by the first and the second light emitting element becomes visually white.
10 more elements
A light emitting device comprising:
- a source signal line;
- a switching transistor;
- a first transistor;
- a second transistor;
- a third transistor;
- a first light emitting element connected to the first transistor;
- a second light emitting element connected to the second transistor;
- and
- a third light emitting element connected to the third transistor,
- wherein a first electrode of the switching transistor is connected to the source signal line and a second electrode of the switching transistor is electrically connected to gate electrodes of the first transistor and the second transistor and the third transistor,
- wherein a first electrode of the first transistor is electrically connected to the first current supply line, and a second electrode of the first transistor is directly connected to a first electrode of the first light emitting element,
- wherein a first electrode of the second transistor is electrically connected to the second current supply line, and a second electrode of the second transistor is directly connected to a second electrode of the first light emitting element and one electrode of the second light emitting element, and
- wherein the first light emitting element emits white light.
10 more elements
A light emitting device comprising:
- a source signal line;
- a switching transistor;
- a first transistor;
- a second transistor;
- a third transistor;
- a first light emitting element connected to the first transistor;
- a second light emitting element connected to the second transistor;
- and a third light emitting element connected to the third transistor,
- wherein a first electrode of the switching transistor is connected to the source signal line and a second electrode of the switching transistor is electrically connected to gate electrodes of the first transistor and the second transistor and the third transistor,
- wherein a first electrode of the first transistor is electrically connected to the first current supply line, and a second electrode of the first transistor is directly connected to a first electrode of the first light emitting element,
- wherein a first electrode of the second transistor is electrically connected to the second current supply line, and a second electrode of the second transistor is directly connected to a second electrode of the first light emitting element and a first electrode of the second light emitting element, and
- wherein the first light emitting element and the second light emitting element emit light so that mixed light by the first and the second light emitting element becomes visually white.
9 more elements
Dependencies are inferred from the claim text.