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US 2003/0189206 A1Published application
Light emitting device and electronic equipment
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorJun Koyama
Life of this patent
Estimating the term…
Abstract
A display device capable of keeping the luminance constant irrespective of temperature change is provided as well as a method of driving the display device. A current mirror circuit composed of transistors is placed in each pixel. A first transistor and a second transistor of the current mirror circuit are connected such that the drain current of the first transistor is kept in proportion to the drain current of the second transistor irrespective of the load resistance value. The drain current of the first transistor is controlled by a driving circuit in accordance with a video signal and the drain current of the second transistor is caused to flow into an OLED, thereby controlling the OLED drive current and the luminance of the OLED.
Claims69
A light emitting device comprising:
- a first, second, and third transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- and
- a power supply line,
- wherein source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof;
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range, and
- wherein the drain region of the first transistor and a gate electrode of the third transistor are connected to each other for a certain period in one frame period.
6 more elements
A light emitting device comprising:
- a first, second, and third transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- and
- a power supply line,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range,
- wherein the drain region of the first transistor and the gate electrode of the third transistor are connected to each other for a certain period in one frame period, and
- wherein the amount of drain current of the first transistor is controlled while the drain region of the first transistor and the gate electrode of the third transistor are connected to each other in order to control the luminance of the organic light emitting diode.
7 more elements
A light emitting device comprising:
- a first, second, and third transistor, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- and
- a power supply line,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range,
- wherein the drain region of the first transistor and the gate electrode of the third transistor are connected to each other for a certain period in one frame period, and
- wherein the amount of drain current of the first transistor is controlled by a video signal while the drain region of the first transistor and the gate electrode of the third transistor are connected to each other in order to control the luminance of the organic light emitting diode.
7 more elements
A light emitting device comprising:
- a first, second, third, fourth, and fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the signal line and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode, and
- wherein the first, second, and third transistors operate in a saturation range.
10 more elements
A light emitting device comprising:
- a first, second, third, fourth, and fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the signal line and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof;
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range, and
- wherein the amount of drain current of the first transistor is controlled in order to control the luminance of the organic light emitting diode.
11 more elements
A light emitting device comprising:
- a first, second, third, fourth, and fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the signal line and the other is connected to a gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range;
- and
- wherein the amount of drain current of the first transistor is controlled by a video signal in order to control the luminance of the organic light emitting diode.
12 more elements
A light emitting device comprising:
- a first, second, third, fourth, fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line;
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the drain region of the first transistor and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode, and
- wherein the first, second, and third transistors operate in a saturation range.
10 more elements
A light emitting device comprising:
- a first, second, third, fourth, fifth transistors, each comprising a source region, a drain region, and agate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the drain region of the first transistor and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range, and
- wherein the amount of drain current of the first transistor is controlled in order to control the luminance of the organic light emitting diode.
11 more elements
A light emitting device comprising:
- a first, second, third, fourth, fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the drain region of the first transistor and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof;
- wherein a source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range, and
- wherein the amount of drain current of the first transistor is controlled by a video signal in order to control the luminance of the organic light emitting diode.
11 more elements
A light emitting device comprising:
- a first, second, third, fourth, fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line;
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the gate electrode of the third transistor;
- wherein one of the source or drain regions of the fifth transistor is connected to the gate electrode of the third transistor and the other is connected to the drain region of the first transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode;
- and
- wherein the first, second, and third transistors operate in a saturation range.
11 more elements
A light emitting device comprising:
- a first, second, third, fourth, fifth transistors, each comprising a source region a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the gate electrode of the third transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the gate electrode of the third transistor and the other of which is connected to the drain region of the first transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to a gate electrode of the second transistor and to the drain region thereof;
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range, and
- wherein the amount of drain current of the first transistor is controlled in order to control the luminance of the organic light emitting diode.
11 more elements
A light emitting device comprising:
- a first, second, third, fourth, fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the gate electrode of the third transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the gate electrode of the third transistor and the other is connected to the drain region of the first transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range, and
- wherein the amount of drain current of the first transistor is controlled by a video signal in order to control the luminance of the organic light emitting diode.
11 more elements
A light emitting device comprising:
- a first, second, third, fourth, and fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to a drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the signal line and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof;
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range,
- wherein the fourth and fifth transistors are turned ON for a certain period in one frame period and the fourth and fifth transistors are turned OFF for a certain period in the same one frame period, and
- wherein the amount of current flowing in the signal line is controlled while the fourth and fifth transistors are turned ON in order to control the luminance of the organic light emitting diode.
12 more elements
A light emitting device comprising:
- a first, second, third, fourth, and fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the drain region of the first transistor and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range,
- wherein the fourth and fifth transistors are turned ON for a certain period in one frame period and the fourth and fifth transistors are turned OFF for a certain period in the same one frame period, and
- wherein the amount of current flowing in the signal line is controlled while the fourth and fifth transistors are turned ON in order to control the luminance of the organic light emitting diode.
12 more elements
A light emitting device comprising:
- a first, second, third, fourth, and fifth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- and
- a scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the gate electrode of the third transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the gate electrode of the third transistor and the other is connected to the drain region of the first transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the first, second, and third transistors operate in a saturation range,
- wherein the fourth and fifth transistors are turned ON for a certain period in one frame period and the fourth and fifth transistors are turned OFF for a certain period in the same one frame period, and
- wherein the amount of current flowing in the signal line is controlled while the fourth and fifth transistors are turned ON in order to control the luminance of the organic light emitting diode.
12 more elements
A light emitting device comprising:
- a first, second, third, fourth, fifth, and sixth transistors, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- a first scanning line;
- and
- a second scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the first scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the signal line and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the gate electrode of the sixth transistor is connected to the second scanning line,
- wherein one of the source or drain regions of the sixth transistor is connected to the power supply line and the other is connected to the gate electrode of the first transistor, and
- wherein the first, second, and third transistors operate in a saturation range.
13 more elements
A light emitting device comprising:
- a first, second, third, fourth, fifth, sixth transistor, each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- a first scanning line;
- and
- a second scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the first scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the drain region of the first transistor and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode,
- wherein the gate electrode of the sixth transistor is connected to the second scanning line,
- wherein one of source or drain regions of the sixth transistor is connected to the power supply line and the other is connected to the gate electrode of the first transistor,
- wherein the first, second, and third transistors operate in a saturation range, and
- wherein the amount of drain current of the first transistor is controlled in order to control the luminance of the organic light emitting diode.
14 more elements
A light emitting device comprising:
- a first, second, third, fourth, fifth, and sixth transistors each comprising a source region, a drain region, and a gate electrode;
- an organic light emitting diode;
- a power supply line;
- a signal line;
- a first scanning line;
- and
- a second scanning line,
- wherein the gate electrodes of the fourth and fifth transistors are connected to the first scanning line,
- wherein one of the source or drain regions of the fourth transistor is connected to the signal line and the other is connected to the drain region of the first transistor,
- wherein one of the source or drain regions of the fifth transistor is connected to the drain region of the first transistor and the other is connected to the gate electrode of the third transistor,
- wherein the source regions of the first and second transistors are connected to the power supply line,
- wherein the gate electrode of the first transistor is connected to the gate electrode of the second transistor and to the drain region thereof,
- wherein the source region of the third transistor is connected to the drain region of the second transistor and the drain region of the third transistor is connected to a pixel electrode of the organic light emitting diode;
- wherein the gate electrode of the sixth transistor is connected to the second scanning line,
- wherein one of the source or drain regions of the sixth transistor is connected to the power supply line and the other is connected to the gate electrode of the first transistor,
- wherein the first, second, and third transistors operate in a saturation range, and
- wherein the amount of drain current of the first transistor is controlled by a video signal in order to control the luminance of the organic light emitting diode.
14 more elements
Dependencies are inferred from the claim text.