Variable-Radius Laser Focal Columns for Complex Glass Apertures
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Solution Overview
Problem
Current laser processing techniques for transparent workpieces, such as glass, are limited in producing complex shapes and are time-consuming and costly due to the nature of Gaussian beam focusing and laser damage and etch processes, which restrict the formation of through substrate vias and surface structures to simple shapes.
Innovation Solution
A method involving a laser beam focal column with a variable radius of maximum intensity, formed using a phase altering sub-assembly including optical elements like axicons, vortex phase plates, and spatial light modulators, which allows for the creation of defect columns with arbitrary shapes and sizes, enabling the formation of complex apertures through transparent workpieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional Gaussian beam focusing and laser damage and etch processes are used, then processing is simpler, but the ability to produce complex shapes is limited and processing time increases
Solution Approach 1:
The patent transforms the laser beam profile from a traditional Gaussian distribution to a Bessel-like focal column with a flat-top intensity distribution. This parameter change in beam geometry enables the creation of defect columns with arbitrary cross-sectional shapes and variable radii along the propagation direction, allowing complex 3D structures to be formed in a single processing step rather than through multiple sequential operations.
Solution Approach 2:
The patent employs pulsed laser operation with specific temporal characteristics to generate the Bessel-like focal column. The periodic pulsed action allows cumulative damage accumulation along the beam propagation path while maintaining precise spatial control, enabling rapid formation of deep defect columns without excessive heat diffusion or material ejection that would occur with continuous wave operation.
2Adaptability or versatility
If additional masking and single-sided etching steps are used to achieve complex TGVs, then shape complexity improves, but process complexity, time, and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for separate masking and etching steps by directly forming the complete 3D defect column structure through single-sided laser processing. The Bessel-like focal column inherently provides the necessary lateral and depth confinement, replacing the function previously served by masks and multi-step etching processes, thereby simplifying the overall manufacturing workflow.
Solution Approach 2:
The laser processing creates the complete defect column geometry in advance through direct writing, including any desired shape variations along the depth direction. This preliminary formation of the final structure eliminates the need for subsequent masking and selective etching operations, as the defect column is already shaped to the exact specifications required for the application.
3Manufacturing precision
If traditional laser beam focusing is used, then equipment is simpler, but manufacturing precision for arbitrary shapes deteriorates
Solution Approach 1:
The patent implements precise control over the laser beam parameters, specifically transforming the intensity distribution from Gaussian to Bessel-like with a flat-top profile. This parameter transformation is achieved through optical elements such as axicons or spatial light modulators, enabling accurate control of the defect column radius and shape along the propagation direction with micrometer-level precision.
Solution Approach 2:
The patent replaces traditional mechanical masking systems with optical field control using Bessel-like beam generation. Instead of physically blocking parts of the beam with masks, the desired shape is achieved through optical interference and diffraction effects inherent to Bessel beam formation, eliminating mechanical complexity while enhancing shape precision.
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 rapid processing of complex shapes in transparent workpieces, reducing time and cost by allowing the formation of apertures with varying radii and shapes, such as hourglass or hollow cone shapes, through controlled laser beam focal columns, facilitating efficient manufacturing.
Implementation Method 1
generates an induced absorption to produce a defect column within the transparent workpiece
Implementation Method 2
directing the laser beam through a phase altering sub-assembly prior to directing the laser beam into the transparent workpiece, wherein the phase altering sub-assembly include one or more optical elements configured to apply an axicon phase modification, a vortex phase modification, and a third phase modification
Implementation Method 3
the axicon is configured to apply the axicon phase modification
Implementation Method 4
the vortex phase plate is configured to apply the vortex phase modification
Implementation Method 5
the third optical element includes a radial Airy phase plate or a focusing lens
Data Source
AI summary
A method of laser processing a transparent workpiece (160) includes directing a laser beam (112) into the transparent workpiece (160) wherein a portion of the laser beam (112) directed into the transparent workpiece (160) includes a laser beam focal column (113) and generates an induced absorption to produce a defect column (172) within the transparent workpiece (160), the laser beam focal column (113) having a radius of maximum beam intensity that is variable along a length of the laser beam focal column (113) such that the radius of maximum beam intensity has at least two non-zero angles of propagation with respect to a center line of the laser beam focal column (113) along the length of the laser beam focal column (113).