OLED Panel Substrate Removal via Tensile Stress Compensation
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Solution Overview
Problem
Compressive stress in the undercoat and TFT layers of a flexible OLED panel leads to warping or wrinkling when the supporting substrate is removed, affecting subsequent processing steps.
Innovation Solution
A laminated body is formed with a resin layer, an inorganic layer having zero or tensile stress, a TFT layer, and a sealing layer in that order on a supporting substrate, and the substrate is then separated using laser irradiation to minimize stress-related distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the supporting substrate is removed to enable flexible OLED panel production, then the panel can achieve flexibility, but the undercoat layer and TFT layer elongate due to compressive stress release, causing warping and wrinkling
Solution Approach 1:
The patent applies preliminary anti-action by forming an inorganic layer with tensile stress before removing the supporting substrate. This tensile stress acts in advance to counterbalance the compressive stress that will be released from the undercoat and TFT layers, preventing warping and wrinkling. The inorganic layer's tensile stress creates a preliminary counter-force that maintains panel flatness during and after substrate removal.
Solution Approach 2:
The patent changes the stress parameter of the inorganic layer from compressive to tensile, or adjusts it to have zero mean stress. By controlling the stress state of the inorganic layer (making it tensile or zero-mean), the overall mean stress of the laminated body is brought closer to zero, which prevents elongation and deformation when the supporting substrate is removed.
2Productivity
If the supporting substrate is removed by laser irradiation, then the panel production process can proceed, but the sudden stress release causes the laminated body to warp and wrinkle
Solution Approach 1:
The inorganic layer with tensile stress is formed in advance to create a counterbalancing force against the compressive stress release. This preliminary anti-action ensures that when laser irradiation removes the supporting substrate and triggers sudden stress release, the tensile stress in the inorganic layer prevents warping and wrinkling, maintaining manufacturing precision throughout the rapid substrate removal process.
Solution Approach 2:
By adjusting the stress parameter of the inorganic layer to be tensile or zero-mean, the patent controls the overall stress state of the laminated body. This parameter change ensures that even during rapid substrate removal by laser irradiation, the mean stress remains close to zero, preventing deformation and maintaining flatness control during high-speed production.
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 likelihood of warping and wrinkling, facilitating easier handling of the laminated body by bringing the mean stress closer to zero, thus improving the panel's flatness and flexibility.
Implementation Method 1
removing the supporting substrate by irradiating the laminated body with laser light
Data Source
AI summary
Included are the steps of: forming a laminated body (7) by disposing a resin layer (12), an inorganic layer (3) having mean stress (Px) of 0 (zero) or having tensile stress, a TFT layer (4), an OLED element layer (5), and a sealing layer (6) in this order on an upper side of a supporting substrate (50); and separating the supporting substrate (50) from the laminated body (7).