Spatial Light Modulator Laser Processing Energy Uniformity
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Solution Overview
Problem
Existing laser processing methods using a phase modulating spatial light modulator to condense laser light to multiple positions result in uneven energy distribution, leading to processing inconsistencies due to variations in the number of condensing positions, and require frequent changes of ND filters, which reduces efficiency.
Innovation Solution
A method and device that uses a phase modulating spatial light modulator to present holograms, allowing for constant laser energy irradiation across multiple positions by distinguishing between 'contribution' and 'non-contribution' light, where 'contribution' light meets a predetermined threshold and 'non-contribution' light is dispersed, maintaining energy consistency regardless of the number of positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-point simultaneous processing is performed by using a plurality of laser light sources, then processing time is shortened, but cost increases and installation area and optical system become complicated
Solution Approach 1:
The patent combines multiple laser light sources into a single laser light source by using optical combining techniques. The spatial light modulator modulates the laser light from one source to create multiple condensing positions, effectively merging the functions of multiple laser sources into one, thereby shortening processing time while avoiding the complexity of multiple independent laser systems
Solution Approach 2:
The patent introduces a spatial light modulator as an intermediary device between the single laser light source and the processing target. This intermediary modulates the laser light to create multiple condensing positions, serving as a mediator that enables multi-point processing without requiring multiple laser sources, thus resolving the contradiction between productivity and device complexity
2Productivity
If the number of condensing positions is increased to shorten processing time, then productivity improves, but energy uniformity across condensing positions deteriorates
Solution Approach 1:
The patent employs a spatial light modulator that dynamically adjusts the phase and amplitude of laser light at different spatial positions. This dynamic modulation capability allows the system to compensate for energy distribution variations across multiple condensing positions, maintaining energy uniformity while increasing the number of processing positions to improve productivity
Solution Approach 2:
The patent changes the optical parameters (phase and amplitude) of the laser light through spatial light modulation. By adjusting these parameters dynamically across different spatial positions, the system achieves uniform energy distribution at multiple condensing positions simultaneously, resolving the contradiction between productivity and manufacturing precision
3Manufacturing precision
If ND filter is replaced to maintain constant laser energy when number of condensing positions changes, then energy uniformity is maintained, but operational efficiency decreases due to frequent filter changes
Solution Approach 1:
The spatial light modulator performs self-adjustment of energy distribution across condensing positions through electronic control. Instead of requiring manual intervention to replace ND filters, the system automatically modulates the laser light parameters to maintain constant energy at each position, thereby maintaining manufacturing precision while eliminating operational inefficiencies
Solution Approach 2:
The patent replaces the mechanical ND filter replacement system with an electronic spatial light modulation system. The electronic modulation of laser parameters substitutes for the mechanical filter changes, maintaining energy consistency through software-controlled optical modulation rather than physical filter replacement, thus improving ease of operation
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 ensures consistent processing energy across varying numbers of condensing positions, reducing processing unevenness and eliminating the need for frequent filter changes, thereby enhancing efficiency and maintaining energy uniformity.
Implementation Method 1
a laser light output from one laser light source is phase-modulated by the spatial light modulator
Implementation Method 2
a hologram is presented on the phase modulating spatial light modulator
Implementation Method 3
the phase-modulated laser light is simultaneously condensed and irradiated to a plurality of positions
Implementation Method 4
processing of a metal surface by abrasion by use of a femtosecond laser light
Implementation Method 5
the abrasion ratio is different depending on the laser light energy
Data Source
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AI summary
A laser processing device 1 includes a laser light source 10, a spatial light modulator 20, a control section 22, and a condensing optical system 30. The spatial light modulator 20 is input with a laser light output from the laser light source 10, presents a hologram for modulating the phase of the laser light in each of a plurality of two-dimensionally arrayed pixels, and outputs the phase-modulated laser light. The control section 22 causes a part of the phase-modulated laser light (incident light) to be condensed at a condensing position existing in a processing region as a laser light (contribution light) having a constant energy not less than a predetermined threshold X. On the other hand, the control section 22 causes a laser light (unnecessary light) other than the contribution light condensed to the condensing position existing in the processing region to be dispersed and condensed at a condensing position existing in a non-processing region as a plurality of laser lights (non-contribution lights) having an energy less than the predetermined threshold X.