Annular Laser Beam Profile for Glass Substrate Separation
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Solution Overview
Problem
Conventional laser processing methods for cutting and separating glass substrates often result in overheating, cracking, and melting, particularly for materials with low coefficients of thermal expansion, leading to weakened edges and reduced edge strength.
Innovation Solution
The use of an annular infrared laser beam profile that distributes energy more intensely on areas adjacent to the contour line rather than directly on it, combined with pulsed laser beam focal lines to create line defects, facilitates controlled separation by inducing thermal stresses without causing excessive damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional laser beam profile is used to cut glass substrates, then the cutting speed can be increased, but overheating, cracking, and melting occur leading to weakened edges
Solution Approach 1:
The patent applies local quality by using an annular laser beam profile that concentrates energy in specific regions (adjacent to the contour line) while leaving other regions (directly on the contour line) with reduced energy. This localized energy distribution enables controlled thermal stress induction for separation without causing harmful overheating and melting at the cut edge, thereby resolving the contradiction between cutting speed and edge quality.
2Productivity
If higher laser power is used to increase processing speed, then productivity improves, but the risk of overheating and damage increases
Solution Approach 1:
The patent changes the beam profile parameter from a conventional Gaussian distribution to an annular distribution. This parameter change allows the system to use higher laser powers for faster processing while the annular shape ensures energy is deposited in a controlled manner adjacent to the contour line, preventing direct overheating at the cut edge and maintaining edge strength and reliability.
3Productivity
If laser energy is concentrated directly on the contour line, then separation efficiency improves, but excessive heating causes melting and cracking
Solution Approach 1:
The patent inverts the conventional approach by concentrating laser energy not directly on the contour line but in the regions adjacent to it. This inversion allows thermal stress to be induced effectively for separation while avoiding direct heating of the contour line, thereby preventing melting and cracking while maintaining separation efficiency.
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 enables precise, efficient, and damage-free separation of glass substrates with low thermal expansion coefficients, reducing the risk of overheating and maintaining edge strength, while allowing for faster processing speeds and a broader power window for given processing speeds.
Implementation Method 1
translating the transparent workpiece and the pulsed laser beam focal line relative to each other thereby laser forming a plurality of line defects along a contour line within the transparent workpiece
Implementation Method 2
directing an infrared laser beam onto the workpiece along or near the contour line to separate the workpiece along the contour line. The infrared laser beam has a beam profile such that a greater distribution of cumulated energy from the infrared laser beam is located in areas adjacent to the contour line than directly on the contour line.
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
A workpiece may be laser processed by a method that may include forming a contour line in the workpiece, and directing an infrared laser beam onto the workpiece along or near the contour line to separate the workpiece along the contour line. The contour line may include defects in the workpiece. The infrared laser beam may have a beam profile such that a greater distribution of cumulated energy from the infrared laser beam is located in areas adjacent to the contour line than directly on the contour line.