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US 8,797,314 B2Granted
Pixel circuit and organic electro-luminescent display apparatus
AssigneeSamsung Display Co., Ltd.
InventorsBo-Yong Chung, Yong-Sung Park, Deok-Young Choi
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Abstract
An organic electro-luminescent display apparatus can compensate for the threshold voltage and voltage drop of the driving transistor. The organic electro-luminescent display apparatus divides and drives an initialization time, thereby improving a contrast ratio. The organic electro-luminescent display apparatus minimizes or reduces the change of a current due to a leakage current by correcting the leakage current corresponding to a data voltage with a fixed power source, thereby improving crosstalk. The organic electro-luminescent display apparatus adjusts the duty of the emission control signal, thereby removing or reducing motion blur.
Claims17
A pixel circuit for driving a light emitting device comprising a first electrode and a second electrode, the pixel circuit comprising:
- a driving transistor comprising a gate electrode, a first electrode, and a second electrode, the gate electrode of the driving transistor being coupled to a second node, the driving transistor being configured to output a driving current corresponding to a data signal;
- a second transistor configured to electrically couple the gate electrode and the second electrode of the driving transistor to each other in response to a current scan signal applied to a gate electrode of the second transistor;
- a third transistor comprising a first electrode configured to receive the data signal, the third transistor being configured to transfer the data signal to a first node in response to the current scan signal;
- a fourth transistor comprising a first electrode coupled to a first power source, the fourth transistor being configured to transfer a voltage from the first power source to the first node in response to a next emission control signal;
- a fifth transistor coupled in series between the second electrode of the driving transistor and the first electrode of the light emitting device, and configured to transfer the driving current from the driving transistor to the first electrode of the light emitting device in response to a current emission control signal;
- a sixth transistor configured to transfer an initialization voltage to the second node in response to a previous scan signal;
- and
- a first capacitor comprising a first electrode coupled to the first node and a second electrode coupled to the second node,
- wherein, during an initialization period, the third transistor and the second transistor are configured to be off and the fourth transistor and the sixth transistor are configured to be on to initialize the first node and the second node, respectively, and
- wherein, during an emission period, the fifth transistor is configured to be on to transfer the driving current to the light emitting device and the fourth transistor is configured to be on to transfer the voltage from the first power source to the first node.
7 more elements
An organic electro-luminescent display apparatus comprising:
- a plurality of pixels;
- a scan driver configured to output previous and current scan signals, and current and next emission control signals to each of the pixels;
- and
- a data driver configured to generate and output data signals to the pixels,
- wherein each of the pixels comprises:
- an organic light emitting diode (OLED) comprising first and second electrodes;
- a driving transistor comprising a gate electrode, a first electrode, and a second electrode, and configured to output a driving current corresponding to one of the data signals;
- a second transistor configured to electrically couple the gate electrode and the second electrode of the driving transistor to each other in response to a respective one of the current scan signals applied to a gate electrode of the second transistor;
- a third transistor comprising a first electrode configured to receive a respective one of the data signals, the third transistor being configured to transfer the respective one of the data signals to a second electrode of the third transistor in response to the respective one of the current scan signals;
- a fourth transistor comprising a first electrode coupled to a first power source, the fourth transistor being configured to transfer a voltage from the first power source to the second electrode of the third transistor in response to a respective one of the next emission control signals;
- a fifth transistor coupled in series between the second electrode of the driving transistor and the first electrode of the OLED, and configured to transfer the driving current from the driving transistor to the first electrode of the OLED in response to a respective one of the current emission control signals;
- a sixth transistor configured to transfer an initialization voltage to the gate electrode of the driving transistor in response to a respective one of the previous scan signals;
- and
- a first capacitor comprising a first electrode coupled to the second electrode of the third transistor and a second electrode of the fourth transistor, and a second electrode coupled to the gate electrode of the driving transistor,
- wherein, during an initialization period, the third transistor and the second transistor are configured to be off and the fourth transistor and the sixth transistor are configured to be on to initialize the first electrode and the second electrode of the first capacitor, respectively, and
- wherein, during an emission period, the fifth transistor is configured to be on to transfer the driving current to the light emitting device and the fourth transistor is configured to be on to transfer the voltage from the first power source to the first electrode of the first capacitor.
13 more elements
Dependencies are inferred from the claim text.