Display device and driving method thereof
First Claim
1. A display device characterized by including a pixel that has means for converting a first current into a voltage, means for holding the converted voltage, means for converting the voltage held into a second current, and means for causing the second current to flow into a light emitting element using a digital video signal.
1 Assignment
0 Petitions
Accused Products
Abstract
Each pixel of a display device has a current supply circuit, a switch portion, and a light emitting element. The light emitting element, the current supply circuit, and the switch portion are connected in series between a power supply reference line and a power supply line. The switch portion is switched between ON and OFF using a digital video signal. The amount of constant current flowing in the current supply circuit is determined by a control signal inputted from the outside of the pixel. When the switch portion is ON, a constant current determined by the current supply circuit flows in the light emitting element and light is emitted. As a result, a low-cost display device can be provided in which the light emitting element can emit light at a constant luminance even when the current characteristic is changed by degradation or the like, which is fast in writing signals in pixels, which can display in gray scales accurately, and which can be reduced in size with a low cost, as well as a driving method of the display device.
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Citations
25 Claims
- 1. A display device characterized by including a pixel that has means for converting a first current into a voltage, means for holding the converted voltage, means for converting the voltage held into a second current, and means for causing the second current to flow into a light emitting element using a digital video signal.
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2. A display device characterized by including a pixel that has means for converting a first current into a voltage, means for holding the voltage converted, means for converting the voltage held into a second current having the same current value as the first current, and means for causing the second current to flow into a light emitting element using a digital video signal.
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3. A display device characterized by including a pixel that has means for converting a first current into a voltage, for holding the voltage converted, and for converting the voltage held into a second current whose current value is in proportion to the first current, and means for causing the second current to flow into a light emitting element using a digital video signal.
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5. A display device including a pixel having a current supply circuit (102) that causes a constant current to flow and a switch portion (101) that uses a digital video signal to switch between ON and OFF, which controls light emission of a light emitting element (106), characterized in that the switch portion (101), the current supply circuit (102), and the light emitting element (106) are connected in series.
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6. A display device including a pixel having a current supply circuit (102), a switch portion (101), a power supply line, and a power supply reference line, with the current supply circuit (102) having a first terminal (A) and a second terminal (B) and fixing a current flowing between the first terminal (A) and the second terminal (B) to a constant value, and the switch portion (101) having a third terminal (C) and a fourth terminal (D) and using a digital video signal to switch a path between the third terminal (C) and the fourth terminal (D) to a conductive or nonconductive state, the display device being characterized in that the current supply circuit (102), the switch portion (101), and a light emitting element (106) are connected between the power supply line and the power supply reference line such that a current flowing between the first terminal (A) and the second terminal (B) flows between an anode and a cathode of the light emitting element (106) when the path between the third terminal (C) and the fourth terminal (D) is made conductive.
- 7. A display device characterized by including a pixel having means for setting a first current as a drain current of a first transistor, means for holding a gate voltage of the first transistor, means for setting the gate voltage as a gate voltage of a second transistor (112) that has the same polarity as the first transistor, and means for causing a drain current of the second transistor (112) to flow into a light emitting element (106) using a digital video signal.
- 11. A display device characterized by including a pixel that has means for inputting a first current into a transistor (112) to set it as a drain current of the transistor (112), means for holding a gate voltage of the transistor (112), and means for causing the drain current of the transistor (112) to flow into a light emitting element (106) using a digital video signal to apply a voltage between source-drain terminals of the transistor (112), the drain current being determined by the gate voltage held.
- 19. A method of driving a display device, characterized by performing a first operation in which a first current inputted to a pixel is converted into a voltage to hold the converted voltage and a second operation in which the voltage held is converted into a second current to cause the second current to flow into a light emitting element using a digital video signal inputted.
Specification