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US 7,612,747 B2Granted
Organic light emitting display
AssigneesChi Mei Optoelectronics Corp., CHI MEI EL Corp.
InventorsChien Hsiang Huang, Hong-Ru Guo, Ming-Chun Tseng
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Abstract
A display having voltage-driven organic light-emitting pixel circuits. Each pixel circuit includes an organic light-emitting diode, a data writing circuit, a capacitor, three transistors, and a switch. The pixel circuit can compensate the threshold voltage variations of low temperature poly silicon thin film transistors. This increases the stability of the voltage-driven organic light-emitting pixel circuits, improves the uniformity of the luminance of the display, and provides a larger aperture ratio for the pixels.
Claims10
A voltage-driven organic light-emitting diode pixel, comprising:
- an organic light-emitting diode (OLED), having a first terminal and a second terminal;
- a data writing circuit, electrically coupled to a data line, a sustaining voltage line and a first scan line, the data writing circuit having an output terminal and determining whether to establish an electrical communication between the output terminal and the data line or between the output terminal and the sustaining voltage line according to a first scan signal carried on the first scan line;
- a capacitor, having a first terminal and a second terminal, the first terminal of the capacitor electrically coupled to the output terminal of the data writing circuit;
- a first transistor, having first and second signal terminals and a control terminal, the first signal terminal of the first transistor electrically coupled to a first predetermined voltage, the second signal terminal of the first transistor electrically coupled to the first terminal of the OLED, and the control terminal of the first transistor electrically coupled to the second terminal of the capacitor;
- a second transistor, having first and second signal terminals and a control terminal, the first signal terminal of the second transistor electrically coupled to the control terminal of the first transistor, the second signal terminal of the second transistor electrically coupled to the first terminal of the OLED, and the control terminal of the second transistor configured to receive the first scan signal;
- a third transistor, having first and second signal terminals and a control terminal, the first signal terminal and the control terminal of the third transistor both electrically coupled to a second scan line, and the second signal terminal of the third transistor electrically coupled to the first signal terminal of the second transistor;
- and
- a first switch, having a switch terminal electrically coupled to the second terminal of the OLED, and another switch terminal electrically coupled to a second voltage, the first switch configured to turn on or turn off according to the first scan signal;
- wherein the first, second and third transistors are of the same type, and scan sequence of the second scan line is arranged before that of the first scan line.
6 more elements
An organic light-emitting diode display panel, which employs multiple scan lines to control turn-on or turn-off of multiple organic light-emitting diode pixels, wherein each of the multiple organic light-emitting diode pixels comprises:
- an organic light-emitting diode (OLED), having a first terminal and a second terminal;
- a data writing circuit, having a plurality of input terminals and an output terminal, the input terminals electrically coupled to a data line, a sustaining voltage line and a first scan line, the data writing circuit determining whether to establish an electrical connection between the output terminal and the data line or between the output terminal and the sustaining voltage line according to a first scan signal carried on the first scan line;
- a capacitor, having a first terminal and a second terminal, the first terminal of the capacitor electrically coupled to the output terminal of the data writing circuit;
- a first transistor, having first and second signal terminals and a control terminal, the first signal terminal of the first transistor electrically coupled to a first predetermined voltage, the second signal terminal of the first transistor electrically coupled to the first terminal of the OLED, and the control terminal of the first transistor electrically coupled to the second terminal of the capacitor;
- a second transistor, having first and second signal terminals and a control terminal, the first signal terminal of the second transistor electrically coupled to the control terminal of the first transistor, the second signal terminal of the second transistor electrically coupled to the first terminal of the OLED, and the control terminal of the second transistor configured to receive the first scan signal;
- a third transistor, having first and second signal terminals and a control terminal, the first signal terminal and the control terminal of the third transistor both electrically coupled to a second scan line, and the second signal terminal of the third transistor electrically coupled to the first signal terminal of the second transistor;
- and
- a first switch, having a first terminal and a second terminal, the second terminal of the first switch electrically coupled to a second predetermined voltage, the first switch configured to turn on or turn off according to the first scan signal;
- wherein the first, second and third transistors are transistors of a same type, and scan sequence of the second scan line is arranged before that of the first scan line;
- wherein, among the organic light-emitting diode pixels that determine whether to establish the electrical connection between the output terminal and the scan line or between the output terminal and the sustaining voltage line according to the first scan signal, at least two of the organic light-emitting diode pixels have the second terminals electrically couple to the first terminal of the first switch.
7 more elements
Dependencies are inferred from the claim text.