Curved Quasi-Non-Diffracting Laser Beams for Non-Planar Glass Separation
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Solution Overview
Problem
Conventional methods for cutting and separating glass substrates are limited by high costs, inefficiencies, and the inability to produce non-planar edges, necessitating a more efficient and reliable method for laser processing of transparent workpieces.
Innovation Solution
The method involves directing a laser beam with a quasi-non-diffracting focal arc that varies in line shift direction, allowing for the formation of curved defects within the transparent workpiece, enabling separation into non-planar edged articles by altering the phase of the laser beam using phase-altering optical elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional laser methods are used for cutting glass substrates, then the process is simple, but the separation speed is slow and the edges cannot achieve non-planar shapes
Solution Approach 1:
The patent applies curvature by transforming the conventional straight laser beam into a curved focal arc. The laser beam is shaped to follow a curved path within the glass substrate, enabling the creation of non-planar edges and bullnose contours. This curvature transformation allows the laser to deposit energy along an arc rather than a straight line, achieving complex edge geometries that were previously impossible with conventional linear scanning methods.
Solution Approach 2:
The patent changes key parameters of the laser beam including its spatial distribution, phase profile, and focal characteristics. By modifying the beam's wavefront curvature and using phase-altering optical elements, the laser energy is distributed along a curved focal arc rather than concentrated at a single point. This parameter transformation enables faster processing by creating a distributed focal region that moves through the material more efficiently.
2Shape
If conventional laser focusing is used, then the beam diverges quickly, but this limits the ability to create curved defects with arbitrary shapes
Solution Approach 1:
The patent uses curvature transformation to create a focal arc instead of a focal point. The laser beam is shaped with a curved wavefront that maintains focus along an arc-shaped path within the substrate. This allows the creation of curved defects with arbitrary shapes and orientations, overcoming the limitation of conventional point-focused beams that can only create linear or simple curved defects through mechanical scanning.
Solution Approach 2:
The patent transitions from two-dimensional beam scanning to three-dimensional focal arc formation. Instead of moving the beam in a plane to create curves, the focal energy is distributed along a curved path in three-dimensional space. This dimensional transformation allows arbitrary curved defects to be created in a single exposure, eliminating the need for complex multi-axis scanning while achieving superior shape control.
3Manufacturing precision
If conventional cutting methods are used, then the process is reliable, but it cannot achieve cleaner separation with non-planar edges
Solution Approach 1:
The patent applies curvature to the laser focal region to create arc-shaped energy deposition patterns within the glass. This curved focal arc enables the formation of non-planar edges and bullnose contours with high precision. The curved beam geometry allows simultaneous creation of complex edge shapes throughout the substrate thickness, achieving manufacturing precision for non-planar features that conventional linear scanning cannot deliver.
Solution Approach 2:
The patent replaces mechanical scanning systems with optical field transformation. Instead of physically moving the laser beam or the substrate to create curved paths, the invention uses phase-altering optical elements to transform the beam's wavefront and create a curved focal arc stationary in space. This substitution of mechanical motion with optical field control eliminates scanning errors, improves repeatability, and enables cleaner separation with precise non-planar edge geometry.
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 faster, cleaner, and more repeatable separation of glass substrates with non-planar edges, overcoming the limitations of conventional methods by achieving low beam divergence and arbitrary curvature in laser beam focal arcs.
Implementation Method 1
directing a laser beam into the transparent workpiece to generate an induced absorption within the transparent workpiece to form a contour
Implementation Method 2
directing the laser beam onto a phase-altering optical element to alter a phase of the laser beam such that the laser beam varies in the line shift direction
Data Source
Figure 1A
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Figure 1C
AI summary
The present application relates to a method of processing a transparent workpiece (160) which comprises : directing a laser beam (112) oriented along a beam path (111) into the transparent workpiece (160) such that a portion of the laser beam (112) directed into the transparent workpiece (160) is a laser beam focal arc (113) and generates an induced absorption within the transparent workpiece (160), the induced absorption producing a defect (172) within the transparent workpiece (160). The laser beam focal arc (113) has a wavelength λ, a spot size w0, and a Rayleigh range ZR that is greater than (I), where FD is a dimensionless divergence factor having a value of 10 or greater. The laser beam focal arc (113) varies in a line shift direction relative to an unaffected beam propagation direction, where the line shift direction extends in an x-direction, a y-direction, or both along a length of the laser beam focal arc, such that the defect (172) varies in the line shift direction.