Flexible Display Barrier Layer Laser Separation
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Solution Overview
Problem
Flexible display devices face issues with transmittance reduction and damage due to moisture permeation and sacrificial layer remnants after separation from support substrates, leading to decreased durability and performance.
Innovation Solution
A display device with a single layer lower barrier layer, typically silicon nitride or silicon oxynitride, is applied on the rear surface of the substrate, and a multi-layer upper barrier layer is used on the front surface, with the energy density of the laser used for separation adjusted based on hydrogen content to prevent damage and maintain transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sacrificial layer is formed between the support substrate and the flexible substrate to enable separation, then the flexible substrate can be separated from the support substrate, but the sacrificial layer remains on the rear face of the flexible substrate causing transmittance decrease
Solution Approach 1:
The patent extracts the harmful function of the sacrificial layer (remaining on substrate causing transmittance loss) by replacing it with a barrier layer that has different properties. The barrier layer is designed to be removed completely during separation while protecting the flexible substrate, thus taking out the problematic remnant layer issue.
Solution Approach 2:
The patent changes the material parameters of the barrier layer (using silicon nitride or silicon oxynitride with specific thickness and hydrogen content) to achieve both protection during separation and complete removal without remnants. By adjusting the hydrogen content and thickness parameters, the barrier layer responds differently to laser irradiation compared to traditional sacrificial layers.
2Ease of manufacture
If the flexible substrate is separated from the support substrate using traditional sacrificial layers, then separation is achieved, but the flexible substrate is damaged or its optical properties are deteriorated
Solution Approach 1:
The barrier layer is formed beforehand on the flexible substrate to cushion and protect it during the separation process. This protective layer absorbs the stress and laser energy during separation, preventing direct damage to the flexible substrate while enabling clean separation from the support substrate.
Solution Approach 2:
The barrier layer acts as an intermediary between the support substrate and the flexible substrate during separation. It mediates the separation process by being the target of laser irradiation, allowing the support substrate to be released from the flexible substrate without directly exposing the flexible substrate to damaging laser energy or mechanical stress.
3Reliability
If multiple layers are used for the barrier layer to improve protection, then moisture barrier performance is enhanced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The single-layer barrier structure performs multiple functions: it protects the flexible substrate during separation, prevents moisture permeation, and can be completely removed without leaving remnants. By making the barrier layer multi-functional, the patent eliminates the need for additional separate layers, thus reducing overall device complexity while maintaining comprehensive protection.
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
The solution effectively prevents damage, deterioration, and moisture permeation, maintaining high transmittance and enhancing the durability and performance of the display device.
Implementation Method 1
separating the first substrate from the support substrate using a laser irradiation process
Implementation Method 2
A laser ablation depth of the barrier layer by the laser may correspond to an energy density of the laser
Data Source
AI summary
A display device may include a first substrate, a lower barrier layer disposed on a rear surface of the first substrate, an upper barrier layer disposed on a front surface of the first substrate, a display structure disposed on the upper barrier layer, and a second substrate disposed on the display structure.