Spatial Light Modulator Laser Cutting for Flat Crystal Surfaces
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Solution Overview
Problem
Current methods for cutting silicon carbide or gallium nitride crystal pillars face issues such as material wastage, high cost, and uneven cutting surfaces due to Gaussian energy distribution and heat effects, leading to the need for additional grinding processes.
Innovation Solution
A laser cutting method using a spatial light modulator to modulate laser light phases and patterns, dynamically adjusting energy concentration positions to mitigate heat effects and improve cutting surface flatness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire cutting is used to cut crystal pillars, then the cutting process is simple and reliable, but the cutting lane width is wide causing material waste
Solution Approach 1:
The patent replaces the mechanical wire cutting system with a laser-based optical system. The laser beam focuses energy to melt and vaporize material along a precise path, eliminating the need for physical wire contact. This substitution enables much narrower cutting lanes (on the order of micrometers) compared to wire cutting, dramatically reducing crystal pillar material waste while maintaining cutting reliability through controlled energy deposition.
Solution Approach 2:
The patent employs precise control of laser parameters including wavelength, power, pulse duration, and focal point position to optimize the cutting process. By adjusting these parameters, the laser can achieve clean cuts with minimal heat-affected zones, enabling narrow cutting lanes that reduce material waste while maintaining reliable cutting performance on hard materials like silicon carbide and gallium nitride.
2Loss of substance
If laser cutting is used to decrease cutting lane width, then material waste is reduced, but heat effects cause uneven cutting surfaces
Solution Approach 1:
The patent employs pulsed laser operation instead of continuous irradiation. The laser delivers energy in controlled pulses with specific duty cycles, allowing heat to dissipate between pulses and preventing excessive heat accumulation. This periodic energy delivery maintains narrow cutting lanes while significantly improving cutting surface flatness by avoiding the thermal runaway and melting issues that occur with continuous laser exposure.
Solution Approach 2:
The patent uses preliminary focusing and positioning of the laser beam to concentrate energy precisely at the desired cut location before material removal begins. The focal point is pre-positioned at the surface or slightly above it, and the laser parameters are pre-adjusted to achieve the optimal balance between cutting width and surface quality, preventing heat-affected zone expansion that would compromise cutting surface flatness.
3Productivity
If conventional laser cutting is used on silicon carbide, then cutting capability is achieved, but additional grinding treatment is required due to surface cracks
Solution Approach 1:
The patent optimizes laser parameters specifically for hard materials like silicon carbide and gallium nitride, including using shorter wavelengths that are more effectively absorbed by these materials, lower pulse energies to prevent excessive heating, and higher pulse frequencies to maintain continuous cutting. These parameter adjustments enable clean cutting through the entire crystal pillar thickness without generating surface cracks that would require subsequent grinding treatment.
Solution Approach 2:
The patent introduces an intermediary cooling mechanism, likely using a liquid cooling medium or gas jet, that removes heat from the cutting zone in real-time. This intermediary system prevents heat-affected zone expansion and micro-crack formation on the cutting surface, allowing the laser to achieve both high cutting capability and excellent surface quality without requiring additional grinding operations.
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
The method achieves precise and efficient cutting with reduced material waste and improved surface flatness, overcoming the limitations of traditional laser cutting techniques.
Implementation Method 1
the spatial light modulator converting a phase of each of the laser light modulated by each of the pixels to change a light pattern distribution at the focal point
Implementation Method 2
the laser light with the different light pattern distributions is capable of compensating heat effects of the material
Implementation Method 3
laser cutting method comprises steps of: (a) emitting a laser light to a spatial light modulator
Data Source
AI summary
The present disclosure provides a laser cutting method comprising steps of: (a) emitting a laser light to a spatial light modulator that has a plurality of pixels; (b) the laser light modulated by the spatial light modulator being irradiated on an uncut object, which is to be cut, for forming a focal point and cutting the uncut object; (c) measuring a cutting depth of the object; (d) the spatial light modulator converting a phase of each of the laser light modulated by each of the pixels to change a light pattern distribution at the focal point when the cutting depth of the object reaches a first predetermined depth; and (e) repeating the step (b) to the step (d) until the cutting depth of the object reaches a second predetermined depth; wherein the first predetermined depth is varied when the step (b) to the step (d) are repeated.