Display Write Transistor Intermediate Node Potential Control
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Solution Overview
Problem
In organic EL display units with a multi-gate configuration, a large reverse bias applied to the write transistor during the light emission period can shift the threshold voltage of the transistor device, compromising the reliability of the screen.
Innovation Solution
A display unit with a pixel array section and a drive circuit section, where the potential of an intermediate node between two transistor devices in the write transistor is set to an intermediate potential between the signal line and the gate electrode of the drive transistor after signal writing, reducing the reverse bias and maintaining the threshold voltage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-gate configuration is used for the write transistor, then oxygen desorption is reduced and threshold value correction is improved, but a large reverse bias shifts the threshold voltage during light emission, compromising screen reliability
Solution Approach 1:
The patent applies dynamics by making the potential of the intermediate node changeable rather than fixed. During the light emission period, the intermediate node potential is dynamically adjusted to an intermediate value between the signal line potential and gate electrode potential, reducing the reverse bias on the write transistor. This dynamic adjustment prevents threshold voltage shifts while maintaining the benefits of multi-gate configuration.
Solution Approach 2:
The patent changes the potential parameter of the intermediate node to resolve the contradiction. By setting the intermediate node potential to an intermediate value during light emission, the reverse bias applied to the write transistor is reduced, preventing threshold voltage shifts. This parameter change maintains screen reliability while avoiding the harmful effects of excessive reverse bias.
2Power
If a multi-gate configuration is used for the write transistor, then current supply capability is improved, but threshold voltage shifts occur during light emission due to large reverse bias
Solution Approach 1:
The patent makes the intermediate node potential dynamic, adjusting it during different operation periods. During light emission, the intermediate node potential is set to an intermediate value that reduces reverse bias on the write transistor, preventing threshold voltage shifts while maintaining the current supply capability provided by the multi-gate configuration.
Solution Approach 2:
The patent changes the potential parameter of the intermediate node to an intermediate value during light emission. This parameter change reduces the reverse bias on the write transistor, preventing threshold voltage shifts while preserving the enhanced current supply capability that the multi-gate configuration provides.
Data Source
AI summary
A display unit includes: a pixel array section configured of pixels arranged in a matrix form, each of the pixels including an electro-optical device, a drive transistor, and a write transistor, the drive transistor configured to drive the electro-optical device, and the write transistor connected between a signal line and a gate electrode of the drive transistor and configured of a plurality of transistor devices connected to one another in series; and a drive circuit section configured to drive each of the pixels of the pixel array section, in which a potential of an intermediate node between two transistor devices selected from the plurality of transistor devices configuring the write transistor is turned to an intermediate potential between a potential of the signal line and a potential of the gate electrode of the drive transistor after completion of signal writing by the write transistor.