Reflective Optical Film in Display Substrates for Laser Lift-Off
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Solution Overview
Problem
In the manufacturing of flexible OLED and Mini-LED display substrates, the thinning of PI substrates to reduce overall thickness leads to damage of circuit structures during the laser lift-off process, and the challenge is to minimize this damage while maintaining efficient lift-off, as reduced laser energy causes difficulties in separating the substrate from the carrier and increases defective rates.
Innovation Solution
A display substrate structure incorporating a sacrificial layer and an optical film layer with higher reflectivity than transmittance, where the optical film layer is designed with alternating dielectric layers to redirect lift-off light, reducing its penetration through the substrate material layer and minimizing damage to circuit structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of the PI substrate is reduced to decrease overall thickness, then the thickness requirement is met, but the circuit structure is damaged during laser lift-off process
Solution Approach 1:
An optical film layer is introduced as an intermediary component between the substrate material layer and sacrificial layer. This optical film layer has reflectivity greater than transmittance, serving as a mediator to redirect laser energy away from the circuit structure while still enabling the lift-off process to proceed effectively.
Solution Approach 2:
The optical properties of the substrate structure are changed by introducing the optical film layer with specific reflectivity and transmittance characteristics. This parameter change allows the substrate to maintain thinness while altering how laser energy interacts with the circuit structure during lift-off, preventing damage through optical parameter optimization.
2Productivity
If laser energy is increased to improve lift-off efficiency, then separation is achieved, but damage to circuit structures increases
Solution Approach 1:
The optical film layer converts potentially harmful laser energy that would damage the circuit into beneficial reflected energy that aids the lift-off process. By having reflectivity greater than transmittance, the film redirects laser energy to enhance separation between the substrate and carrier while protecting the circuit structure from direct laser exposure.
Solution Approach 2:
The optical film layer acts as a mediator that intercepts and redirects laser energy, preventing direct interaction between the high-energy laser beam and the circuit structure. This intermediary function allows high laser energy to be used for lift-off efficiency without the harmful side effect of circuit damage.
3Reliability
If laser energy is decreased to protect circuit structures, then damage is reduced, but lift-off efficiency decreases
Solution Approach 1:
The optical film layer serves as a mediator that optimizes laser energy distribution. It reflects a portion of the laser energy back toward the sacrificial layer to maintain lift-off efficiency, while simultaneously protecting the circuit structure by preventing direct laser exposure, thus resolving the contradiction between protection and efficiency.
Solution Approach 2:
By changing the optical parameters of the substrate structure through the optical film layer, the system achieves a new operating point where lower laser energy can be used effectively. The reflectivity-greater-than-transmittance property of the optical film allows energy redirection that maintains lift-off capability at reduced laser power levels.
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 configuration enhances the lift-off efficiency, reduces product defects, and lowers manufacturing costs by effectively absorbing and redirecting lift-off light, thereby improving the quality and reliability of the display substrates.
Implementation Method 1
an optical film layer between the substrate material layer and the sacrificial layer which are stacked; a reflectivity of the optical film layer is greater than a transmittance of the optical film layer
Implementation Method 2
irradiating the sacrificial layer from a side of the carrier substrate away from the sacrificial layer by using lift-off light to lift the sacrificial layer off from the carrier substrate
Data Source
AI summary
A display substrate, a manufacturing method therefor and a display device are provided. The display substrate includes a substrate structure layer, the substrate structure layer includes a substrate material layer, a sacrificial layer and an optical film layer between the substrate material layer and the sacrificial layer which are stacked; a reflectivity of the optical film layer is greater than a transmittance of the optical film layer.