TFT Orientation on Flexible Substrates for Display Manufacturing
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Solution Overview
Problem
Active matrix organic electroluminescence (EL) displays using flexible substrates face challenges due to dimensional changes during production, affecting TFT position and channel length, leading to display performance deterioration.
Innovation Solution
Forming TFTs with the channel length between the source and drain in the direction of two orthogonal directions on the substrate where the substrate has a smaller dimensional change ratio, providing larger connection margins and preventing property changes caused by contact failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible substrate is used to enable display flexibility and weight reduction, then adaptability and ease of operation are improved, but manufacturing precision deteriorates due to substrate dimensional changes during production
Solution Approach 1:
The patent changes the orientation parameter of the TFT channel length to align with the substrate's smaller dimensional change direction. This parameter adjustment compensates for substrate expansion/contraction effects, maintaining TFT position accuracy and channel length consistency despite using flexible substrates that undergo dimensional changes during production and operation.
2Manufacturing precision
If TFTs are formed with channel length in the direction of smaller dimensional change, then manufacturing precision is improved, but device complexity increases due to alignment requirements
Solution Approach 1:
The patent applies local quality by making the TFT channel length orientation specific to the substrate's dimensional change characteristics. Instead of uniform treatment in all directions, the channel length is deliberately oriented along the direction with smaller dimensional change, creating a localized optimization that improves precision without requiring complex global alignment systems.
Data Source
AI summary
A method for producing a display comprising: forming a plurality of pixels arrayed on a flexible substrate and independently driven by TFTs, wherein the TFTs are formed in such a manner that the direction of the channel length L between the source and drain of each TFT is the direction of two orthogonal directions on the substrate in which the substrate has a smaller dimensional change ratio than the other direction. When the TFTs include a switching TFT and a driving TFT, the TFTs are formed in such a manner that the direction of the channel length between the source and drain of at least the driving TFT is the direction of the two orthogonal directions on the substrate in which the substrate has a smaller dimensional change ratio than the other direction.