Adjustable Laser Focal Line Cutting for Transparent Materials
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Solution Overview
Problem
Conventional laser glass cutting techniques are time-consuming due to the need for multiple pulses to create damage lines, limiting throughput and efficiency in high-tech industries such as flat panel displays and smartphones.
Innovation Solution
The use of an ultrashort pulse laser beam with adjustable line focus to create precise defects in transparent materials, allowing for controlled separation by inducing multi-photon absorption and mechanical or thermal stress, enabling rapid and precise cutting with minimal debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional Gaussian laser beams are used for glass cutting, then the laser beam can be tightly focused to create damage lines, but a large number of pulses are required which makes the process time-consuming and limits throughput
Solution Approach 1:
The patent changes the fundamental parameter of laser beam geometry from a point focus (Gaussian beam) to a line focus. This parameter change allows the laser energy to be distributed along a line rather than concentrated at a single point, enabling the creation of damage lines with fewer pulses while maintaining precision, thereby resolving the contradiction between manufacturing precision and productivity
Solution Approach 2:
The invention transitions from one-dimensional point focusing to two-dimensional line focusing by introducing a cylindrical lens or similar optical element that focuses the laser beam in one dimension while maintaining a line profile in the perpendicular dimension. This dimensional change enables simultaneous damage line creation across the glass thickness, improving throughput without sacrificing precision
2Reliability
If multiple laser pulses are used to create damage lines in glass, then the desired damage can be achieved, but the process becomes time-consuming and efficiency is reduced
Solution Approach 1:
By changing the laser beam parameter from point-focused to line-focused, the patent achieves reliable damage line creation in fewer pulses. The line focus distributes energy along the desired cut path, creating consistent damage lines with high reliability while reducing the number of pulses required, thus minimizing processing time loss
3Manufacturing precision
If the laser beam is tightly focused to create precise damage lines, then manufacturing precision is improved, but the number of pulses required increases which reduces productivity
Solution Approach 1:
The patent applies dimensional change by transforming the laser focus from a point (0D) to a line (1D) using cylindrical optics. This allows the beam to maintain tight focus in the dimension perpendicular to the line (ensuring cut precision) while extending along the cut path (reducing the number of pulses needed), thereby resolving the contradiction between precision and productivity
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 method allows for high-speed, precise cutting of transparent materials with reduced sub-surface damage and debris, improving manufacturing efficiency and enabling the processing of various materials with different thicknesses and stress levels.
Implementation Method 1
By focusing the ultrashort pulse laser beam to a line focus, multi-photon absorption is induced in the transparent material, creating laser-induced defects along the focal line path
Implementation Method 2
By spacing the laser-induced features sufficiently close together, a controlled region of mechanical weakness within the transparent material can be created and the transparent material can be precisely fractured or separated along the path defined by the series of laser-induced defects
Implementation Method 3
an additional separation step may be needed. Hence the ultrashort, line focus laser pulse(s) may be optionally followed by a carbon dioxide (CO2) laser or other source of thermal stress to effect fully automated separation of a transparent material or part from a substrate
Data Source
AI summary
A system for and a method of processing a transparent material, such as glass, using an adjustable laser beam line focus are disclosed. The system for processing a transparent material includes a laser source operable to emit a pulsed laser beam, and an optical assembly (6′) disposed within an optical path of the pulsed laser beam. The optical assembly (6′) is configured to transform the pulsed laser beam into a laser beam focal line having an adjustable length and an adjustable diameter. At least a portion of the laser beam focal line is operable to be positioned within a bulk of the transparent material such that the laser beam focal line produces a material modification along the laser beam focal line. Method of laser processing a transparent material by adjusting at least one of the length of the laser beam focal line and the diameter of the laser beam focal line is also disclosed.