Flexible Substrate Laser Lift-Off Bridge Protection
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Solution Overview
Problem
The existing laser lift-off process for manufacturing flexible display substrates often results in the breaking of connecting bridge regions, leading to cracking of the encapsulation film layer and breakage of metal wirings, which reduces product yield.
Innovation Solution
A method involving the sequential formation and processing of multiple flexible base substrate layers with strategically designed via holes and buffer layers to create weak points at junctions, allowing for controlled laser lift-off and minimizing damage to the encapsulation structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser lift-off process is used to separate flexible layer from rigid underlaying base substrate, then the flexible substrate can be obtained, but the connecting bridge region is easily broken and metal wirings breakage occurs
Solution Approach 1:
The patent divides the base substrate into multiple segments (first base substrate layer, second base substrate layer, third base substrate layer) separated by via holes. This segmentation allows the laser lift-off force to be distributed and redirected to specific sacrifice regions rather than concentrating stress on the connecting bridge regions, preventing wiring breakage while enabling flexible substrate release.
Solution Approach 2:
The patent introduces sacrifice regions as intermediary elements between the rigid underlaying base substrate and the flexible substrate. These sacrifice regions act as mediators that absorb the laser lift-off force and protect the connecting bridge regions and metal wirings from damage during the separation process.
2Ease of manufacture
If laser lift-off process is used to separate flexible layer from rigid underlaying base substrate, then the flexible substrate can be obtained, but the encapsulation film layer cracks
Solution Approach 1:
The base substrate is segmented into multiple layers with via holes creating distinct regions. This segmentation allows controlled separation at sacrifice regions while maintaining encapsulation film integrity in the connecting bridge regions, preventing cracking during lift-off.
Solution Approach 2:
The patent extracts and removes specific sacrifice regions from the base substrate structure. By taking out these predetermined sacrifice regions, the laser lift-off force is directed to these removed areas rather than the encapsulation film layer, preventing film cracking while enabling substrate release.
3Adaptability or versatility
If via holes are formed to improve deformability, then the flexible display device can be made more flexible, but the structural strength is reduced
Solution Approach 1:
The patent applies local quality by creating via holes with specific characteristics (size, depth, distribution) in predetermined sacrifice regions. This local modification allows the substrate to have different properties in different areas: flexible where needed and strong where required, optimizing both adaptability and strength.
Solution Approach 2:
The via holes are nested within the base substrate layers, creating a hierarchical structure. The first, second, and third base substrate layers are nested with via holes penetrating through them, allowing controlled flexibility while maintaining overall structural integrity through the layered nested design.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the breakage of metal wirings in the connecting bridge region and increases product yield by protecting the sidewall encapsulation structure during the laser lift-off process.
Implementation Method 1
an ultraviolet laser is usually used to irradiate the flexible layer from a back surface of the rigid underlaying base substrate to break molecular chains between the flexible layer of an irradiated region and the rigid underlaying base substrate
Implementation Method 2
to break molecular chains between the flexible layer of an irradiated region and the rigid underlaying base substrate
Data Source
AI summary
A flexible substrate, a preparation method therefor and a flexible display substrate. The flexible substrate comprises a plurality of spaced island regions and a plurality of bridge regions connected between different island regions, and has a plurality of openings in non-island regions and non-bridge regions. Each island region is provided with a plurality of layered structures. Each layered structure comprises, sequentially arranged from bottom to top: a first flexible base layer, a first buffer layer and a second flexible base layer, wherein the orthographic projection of the surface of the side of the first buffer layer facing the first flexible base layer on the first flexible base layer is greater than that of the surface of the side of the first flexible base layer facing the first buffer layer on the first flexible base layer.