Flexible Driving Substrate Hollowed Insulating Layer Bending
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Solution Overview
Problem
The existing Micro/Mini-LED display technology faces challenges in manufacturing large-size LED display substrates due to limitations in transfer technology, requiring splicing of small-size substrates, which is hindered by the difficulty in bending substrates with inorganic layers having high Young's modulus, making it hard to coexist with TFT manufacturing processes.
Innovation Solution
A driving substrate with a flexible base, thin film transistors, and a conductive pattern layer, featuring a hollowed-out inorganic insulating layer in the bendable region to reduce Young's modulus, allowing for substrate bending while maintaining electrical integrity, and a method for manufacturing this substrate that includes forming thin film transistors and conductive patterns with specific thicknesses and structures to facilitate splicing and bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic insulating layers are formed during TFT manufacturing process, then electrical insulation and device reliability are improved, but substrate flexibility and bendability deteriorate due to high Young's modulus
Solution Approach 1:
The inorganic insulating layer is segmented into different regions: a first inorganic insulating layer in the display region and a second inorganic insulating layer in the bendable region. This segmentation allows each region to have different structural characteristics optimized for its specific function.
Solution Approach 2:
The patent applies local quality by making the inorganic insulating layer thickness and structure location-dependent. The first inorganic insulating layer has greater thickness in the display region for reliable insulation, while the second inorganic insulating layer has reduced or zero thickness in the bendable region to maintain flexibility. This local differentiation resolves the contradiction between electrical insulation requirements and bendability requirements.
2Area of stationary object
If small-size LED display substrates are spliced to form large-size substrate, then the limitation of transfer technology is overcome, but gaps between substrates and bonding complexity increase
Solution Approach 1:
The patent performs preliminary bending of the substrate in the bendable region before the splicing process. This preliminary action prepares the substrate for easier bonding by pre-positioning the bendable region, reducing the complexity of the splicing operation and improving bonding efficiency.
Solution Approach 2:
The bendable region acts as an intermediary element between the display region and the bonding region. It provides a flexible transition zone that facilitates the splicing process by allowing the substrate to be bent and positioned for bonding without compromising the rigid display region.
3Productivity
If peripheries of substrates are bent to reduce gaps during splicing, then bonding efficiency is improved, but substrate stress and risk of damage increase
Solution Approach 1:
The substrate is segmented into a rigid display region and a flexible bendable region. This segmentation allows bending to be confined to the bendable region only, protecting the display region from stress and damage while still enabling efficient splicing operations.
Solution Approach 2:
The patent applies local quality by differentiating the mechanical properties of different substrate regions. The bendable region is designed with reduced inorganic insulating layer thickness to provide flexibility for bending during splicing, while the display region maintains full thickness for structural integrity and stress resistance.
Data Source
AI summary
The present disclosure provides a driving substrate including: a flexible substrate base, a plurality of thin film transistors on the flexible substrate base and a first conductive pattern layer on a side of the thin film transistors distal to the flexible substrate base. The first conductive pattern layer includes: a plurality of first connection terminals in the display region and a plurality of signal supply lines in the bendable region. A first number of first connection terminals are electrically coupled to first electrodes of the plurality of thin film transistors. The plurality of signal supply lines are coupled to a second number of first connection terminals other than the first number of first connection terminals. At least one inorganic insulating layer including a hollowed-out pattern in the bendable region is between the first conductive pattern layer and the flexible substrate base.