Display device and driving method thereof
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsShunpei Yamazaki, Mitsuaki Osame, Jun Koyama
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Abstract
In an active matrix EL display device, a drive mode is switched between constant voltage drive and constant current drive according to display contents. Whether an OLED is driven at constant current or driven at constant voltage is determined according to whether a driving TFT is driven in a saturation region or driven in a linear region. The separation between the saturation region and the linear region is determined according to a voltage applied to the gate of the TFT and a voltage applied to the OLED. By controlling those voltages, the constant voltage drive and the constant current drive can be separately used, thereby allowing a use in which respective advantages of the both drives are utilized.
Claims84
A display device comprising:
- a plurality of pixels arranged in matrix on a substrate, each of the pixels having an OLED;
- a plurality of source signal lines and a plurality of gate signal lines on the substrate;
- and
- at least one circuit for switching between a first drive mode for driving the OLED at a constant current and a second drive mode for driving the OLED at a constant voltage.
A display device comprising:
- a plurality of pixels arranged in matrix on a substrate, each of the pixels having an OLED, at least one switching TFT, and at least one OLED driving TFT;
- a plurality of source signal lines and a plurality of gate signal lines on the substrate;
- and
- at least one circuit for switching between a first drive mode for driving the OLED driving TFT in a saturation region and a second drive mode for driving the OLED driving TFT in a linear region.
A display device comprising:
- a plurality of pixels arranged in matrix on a substrate, each of the pixels having an OLED, at least one switching TFT, and at least one OLED driving TFT;
- a plurality of source signal lines and a plurality of gate signal lines on the substrate;
- at least one circuit for switching among a first drive mode for driving the OLED driving TFT in a saturation region, a second drive mode for driving the OLED driving TFT in a linear region, and a third drive mode for driving the OLED driving TFT in a middle region between the linear region and the saturation region.
A method of driving a display device in which a plurality of pixels, a plurality of source signal lines, and a plurality of gate signal lines are arranged in matrix on a substrate, each of the pixels having an OLED, the method comprising:
- driving the display device by switching between a first drive method for driving the OLED at a constant current and a second drive method for driving the OLED at a constant voltage.
A method of driving a display device in which a plurality of pixels, a plurality of source signal lines, and a plurality of gate signal lines are arranged in matrix on a substrate, each of the pixels having an OLED, at least one switching TFT, and at least one OLED driving TFT, the method comprising:
- driving the display device by switching between a first drive method for driving the OLED driving TFT in a saturation region and a second drive method for driving the OLED driving TFT in a linear region.
A method of driving a display device in which a plurality of pixels, a plurality of source signal lines, and a plurality of gate signal lines are arranged in matrix on a substrate, each of the pixels having an OLED, at least one switching TFT, and at least one OLED driving TFT, the method comprising:
- driving the display device by switching among a first drive method for driving the OLED driving TFT in a saturation region, a second drive method for driving the OLED driving TFT in a linear region, and a third drive method for driving the OLED driving TFT in a middle region between the linear region and the saturation region.
A display device comprising:
- a plurality of pixels arranged in matrix on a substrate, each of the pixels having a light emitting element;
- a plurality of source signal lines and a plurality of gate signal lines on the substrate;
- at least one circuit for switching between a first drive mode for driving the light emitting element at a constant current and a second drive mode for driving the light emitting element at a constant voltage.
A display device comprising:
- a plurality of pixels, arranged in matrix on a substrate, each of the pixels having a light emitting element, at least one switching TFT, and at least one light emitting element driving TFT;
- a plurality of source signal lines and a plurality of gate signal lines on the substrate;
- at least one circuit for switching between a first drive mode for driving the light emitting element driving TFT in a saturation region and a second drive mode for driving the light emitting element driving TFT in a linear region.
A display device comprising:
- a plurality of pixels arranged in matrix on a substrate, each of the pixels having a light emitting element, at least one switching TFT, and at least one light emitting element driving TFT;
- a plurality of source signal lines and a plurality of gate signal lines on the substrate;
- at least one circuit for switching among a first drive mode for driving the light emitting element driving TFT in a saturation region, a second drive mode for driving the light emitting element driving TFT in a linear region, and a third drive mode for driving the light emitting element driving TFT in a middle region between the linear region and the saturation region.
A method of driving a display device in which a plurality of pixels, a plurality of source signal lines, and a plurality of gate signal lines are arranged in matrix on a substrate, each of the pixels having a light emitting element, the method comprising:
- driving the display device by switching between a first drive method for driving the light emitting element at a constant current and a second drive method for driving the light emitting element at a constant voltage.
A method of driving a display device in which a plurality of pixels, a plurality of source signal lines, and a plurality of gate signal lines are arranged in matrix on a substrate, each of the pixels having a light emitting element, at least one switching TFT, and at least one light emitting element driving TFT, the method comprising:
- driving the display device by switching between a first drive method for driving the light emitting element driving TFT in a saturation region and a second drive method for driving the light emitting element driving TFT in a linear region.
A method of driving a display device in which a plurality of pixels, a plurality of source signal lines, and a plurality of gate signal lines are arranged in matrix on a substrate, each of the pixels having an light emitting element, at least one switching TFT, and at least one light emitting element driving TFT, the method comprising:
- driving the display device by switching among a first drive method for driving the light emitting element driving TFT in a saturation region, a second drive method for driving the light emitting element driving TFT in a linear region, and a third drive method for driving the light emitting element driving TFT in a middle region between the linear region and the saturation region.
Dependencies are inferred from the claim text.