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US 8,026,877 B2Granted
Element substrate and light-emitting device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsMitsuaki Osame, Aya Anzai, Yu Yamazaki, Ryota Fukumoto
Life of this patent
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Abstract
A potential of a gate of a driving transistor is fixed, and the driving transistor is operated in a saturation region, so that a current is supplied thereto anytime. A current control transistor operating in a linear region is disposed serially with the driving transistor, and a video signal for transmitting a signal of emission or non-emission of the pixel is input to a gate of the current control transistor via a switching transistor.
Claims41
A light-emitting device comprising:
- a pixel comprising:
- a light-emitting element,
- a first transistor for determining a value of a current flowing to the light-emitting element,
- a second transistor for determining a light emission or non light emission of the light-emitting element depending on a video signal input through a signal line,
- a third transistor for controlling an input of the video signal, and
- a fourth transistor for forcing the light-emitting element into a non-emission state irrelevant from the video signal,
- wherein the light-emitting element, the first transistor, and the second transistor are connected in series between a first power line and a counter electrode of the light-emitting element,
- wherein a source of the first transistor is connected to the first power line and a gate electrode of the first transistor is connected to a second power line so that a voltage between the gate electrode and the source of the first transistor is constantly fixed,
- wherein the first transistor has a channel length longer than a channel width, and the second transistor has a channel length equal to or shorter than a channel width, and
- wherein a ratio of the channel length to the channel width of the first transistor is 5 or more.
7 more elements
A light-emitting device comprising:
- a pixel comprising:
- a light-emitting element,
- a first transistor for determining a value of a current flowing to the light-emitting element, and
- a second transistor for determining a light emission or non light emission of the light-emitting element depending on a video signal input through a signal line,
- wherein the light-emitting element, the first transistor, and the second transistor are connected in series between a first power line and a counter electrode of the light-emitting element,
- wherein a source of the first transistor is connected to the first power line and a gate electrode of the first transistor is connected to a second power line so that a voltage between the gate electrode and the source of the first transistor is constantly fixed,
- wherein the first transistor has a channel length longer than a channel width, and the second transistor has a channel length equal to or shorter than a channel width, and
- wherein a ratio of the channel length to the channel width of the first transistor is 5 or more.
5 more elements
A light-emitting device comprising:
- a pixel comprising:
- a light-emitting element,
- a first transistor for determining a value of a current flowing to the light-emitting element,
- a second transistor for determining a light emission or non light emission of the light-emitting element depending on a video signal input through a signal line, and
- a third transistor for controlling an input of the video signal,
- wherein the light-emitting element, the first transistor, and the second transistor are connected in series between a first power line and a counter electrode of the light-emitting element,
- wherein a source of the first transistor is connected to the first power line and a gate electrode of the first transistor is connected to a second power line so that a voltage between the gate electrode and the source of the first transistor is constantly fixed,
- wherein the first transistor has a channel length longer than a channel width, and the second transistor has a channel length equal to or shorter than a channel width, and
- wherein a ratio of the channel length to the channel width of the first transistor is 5 or more.
6 more elements
An element substrate comprising:
- a pixel comprising:
- a pixel electrode;
- a first transistor for determining a value of a current flowing to the pixel electrode, and
- a second transistor for determining a supply or non-supply of the current to the pixel electrode depending on a video signal input through a signal line,
- wherein the first transistor and the second transistor are connected in series between a first power line and the pixel electrode,
- wherein a source of the first transistor is connected to the first power line and a gate electrode of the first transistor is connected to a second power line so that a voltage between the gate electrode and the source of the first transistor is constantly fixed,
- wherein the first transistor has a channel length longer than a channel width, and the second transistor has a channel length equal to or shorter than a channel width, and
- wherein a ratio of the channel length to the channel width of the first transistor is 5 or more.
5 more elements
An element substrate comprising:
- a first power line;
- a second power line;
- a scan line;
- a signal line;
- a pixel electrode;
- a first transistor;
- a second transistor;
- and
- a third transistor,
- wherein one of a source and a drain of the first transistor is connected to the pixel electrode,
- wherein one of a source and a drain of the second transistor is connected to the other of the source and the drain of the first transistor,
- wherein the other of the source and the drain of the second transistor is connected to the first power line,
- wherein a gate electrode of the first transistor is connected to the second power line,
- wherein one of a source and a drain of the third transistor is connected to a gate electrode of the second transistor,
- wherein the other of the source and the drain of the third transistor is connected to the signal line,
- wherein a gate electrode of the third transistor is connected to the scan line,
- wherein the first transistor has a channel length longer than a channel width, and the second transistor has a channel length equal to or shorter than a channel width, and
- wherein a ratio of the channel length to the channel width of the first transistor is 5 or more.
15 more elements
An element substrate comprising:
- a first power line;
- a second power line;
- a scan line;
- a signal line;
- a pixel electrode;
- a first transistor;
- a second transistor;
- and
- a third transistor,
- wherein one of a source and a drain of the first transistor is connected to the first power line,
- wherein one of a source and a drain of the second transistor is connected to the other of the source and the drain of the first transistor,
- wherein the other of the source and the drain of the second transistor is connected to the pixel electrode,
- wherein a gate electrode of the first transistor is connected to the second power line,
- wherein one of a source and a drain of the third transistor is connected to a gate electrode of the second transistor,
- wherein the other of the source and the drain of the third transistor is connected to the signal line,
- wherein a gate electrode of the third transistor is connected to the scan line,
- wherein the first transistor has a channel length longer than a channel width, and the second transistor has a channel length equal to or shorter than a channel width, and
- wherein a ratio of the channel length to the channel width of the first transistor is 5 or more.
15 more elements
Dependencies are inferred from the claim text.