Oxide TFT Branching for Heat Dissipation in Shift Registers
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Solution Overview
Problem
Oxide thin-film transistors (Oxide TFTs) in display panels suffer from rapid threshold voltage drift due to heat generation, leading to failure, which is not effectively addressed by existing shift register units.
Innovation Solution
A shift-register unit design featuring oxide thin-film transistors with branching sources and drains, and varying semiconductor branch widths, along with a specific ratio of channel widths in pull-down controlling circuits, to manage heat dissipation and maintain stable voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide thin-film transistors are used in shift register units, then high electron mobility and low leakage current are achieved, but heat generation causes rapid threshold voltage drift and transistor failure
Solution Approach 1:
The source and drain electrodes are divided into multiple branches (first source branch, second source branch, first drain branch, second drain branch) instead of single continuous structures. This segmentation reduces the concentration of current flow and heat generation in any single region, distributing thermal load across multiple pathways while maintaining the overall transistor function and electrical connectivity.
Solution Approach 2:
The patent introduces a width ratio constraint between semiconductor branches (0.5 ≤ width of first semiconductor branch / width of second semiconductor branch ≤ 2.0) to optimize local heat dissipation characteristics. Different branch widths create varying thermal resistance and heat dissipation rates in different regions, allowing heat to be managed more effectively at the local level while maintaining overall device performance.
2Temperature
If uniform semiconductor branch widths are used, then manufacturing simplicity is maintained, but heat dissipation efficiency is reduced leading to threshold voltage drift
Solution Approach 1:
The patent changes the geometric parameter (width) of semiconductor branches from uniform to non-uniform, specifically implementing a width ratio between 0.5 and 2.0 for different branches. This parameter variation optimizes heat dissipation by creating different thermal pathways and resistance values, allowing more efficient heat distribution and dissipation without requiring complex manufacturing processes, as the ratio range provides a practical balance between performance and manufacturability.
Data Source
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AI summary
The present disclosure provides a shift-register unit, a grid driving circuit and a displaying device, which relates to the technical field of displaying. In the present disclosure, the oxide-semiconductor layers of the oxide thin-film transistors may be delimited into regions according to the total channel widths and the channel lengths required by the oxide thin-film transistors in the shift-register unit, wherein the sum of the widths of the independent semiconductor branches obtained by the delimitation is equal to the required total channel width. Accordingly, one oxide thin-film transistor can realize the required total channel width by using the one or more semiconductor branches, to ensure the normal operation of the oxide thin-film transistor, whereby the oxide-semiconductor layers of the different oxide thin-film transistors can be configured differently, to realize the purpose of reducing the border frame of the displaying device. Moreover, the semiconductor branches of a lower size and the gaps between the semiconductor branches can be used for heat dissipation, thereby preventing failure of the oxide thin-film transistors caused by heat accumulation of the oxide semiconductor.