Laser Homogenizing Illumination Optical System for Uniform Irradiance
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Solution Overview
Problem
Achieving high laser power illumination for 2D and 3D printing and engraving with uniform irradiance distribution onto rectangular pixelated spatial light modulators is difficult and expensive using single laser devices.
Innovation Solution
A multichannel fiber cable system combined with collimation and beam shaping optics, including a multiple lens array and objective lens, to collect and spatially homogenize light from multiple high power lasers, producing a uniform top hat irradiance distribution on the spatial light modulator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single high power laser device is used to illuminate rectangular pixelated SLM, then high laser power is achieved, but the cost increases and the irradiance distribution becomes non-uniform
Solution Approach 1:
The patent divides a single high-power laser source into multiple lower-power laser beams using beam splitting optics. These segmented beams are then individually directed to different regions of the rectangular SLM, enabling high total power illumination while maintaining uniform irradiance distribution across the pixelated surface.
Solution Approach 2:
The patent applies different optical path configurations to different regions of the SLM, with each beam tailored to illuminate specific pixel rows or columns. This local optimization ensures that each region receives appropriate irradiance while collectively achieving uniform distribution across the entire rectangular surface.
2Ease of manufacture
If multiple lasers are combined to achieve high power, then cost and uniformity improve, but the device complexity increases
Solution Approach 1:
The patent merges multiple laser beams into a unified illumination pattern on the SLM using beam combining optics. The beam combining unit integrates the segmented beams spatially and temporally, creating a coherent high-power illumination field that maintains uniform irradiance distribution while avoiding the need for complex independent control of each laser source.
Solution Approach 2:
The optical system is designed with multi-functional components that perform multiple operations: beam splitting, beam shaping, beam combining, and uniformity correction are achieved through integrated optical elements rather than separate dedicated components for each function, thereby reducing overall system complexity.
3Device complexity
If conventional optics are used for high power laser illumination, then the system is simple, but the irradiance distribution is non-uniform and angular distribution is incorrect
Solution Approach 1:
The patent introduces intermediary optical elements between the laser source and SLM, including beam shaping optics and homogenization units. These intermediary components transform the initial non-uniform laser beam profile into a uniform rectangular distribution that matches the SLM pixel array, while also correcting the angular distribution to ensure proper illumination geometry.
Solution Approach 2:
The patent modifies key optical parameters including beam diameter, divergence angle, and irradiance profile through controlled transformation in the optical path. By adjusting these parameters through specialized optics, the system achieves precise control over both spatial uniformity and angular distribution without requiring excessive system complexity.
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 system effectively achieves uniform irradiance distribution and desired angular distribution, overcoming the challenges of achieving high laser powers efficiently and cost-effectively for 2D and 3D printing and engraving applications.
Implementation Method 1
The multichannel fiber cable is designed to collect light from high power fiber coupled lasers and produce an aligned array of one or more optical fibers at the output of the cable
Implementation Method 2
The light output from the cable may be collimated and relayed to a multiple lens array
Implementation Method 3
a multiple lens array (e.g., a fly's eye lens array) intentionally designed to spatially homogenize and shape the light into an array of beams or beamlets
Implementation Method 4
an objective lens. The design of the collimation and beam shaping optics, multiple lens array, and objective lens combine to produce the required spatial size of the illumination pattern
Data Source
AI summary
An illuminator optical system combines, homogenizes, and shapes light spatially and angularly from one or more high power fiber coupled lasers. It may include a multichannel fiber cable, collimation and beam shaping optics, a multiple lens array (e.g., fly's eye lens array), and an objective lens. The multichannel fiber collects the light from the high power fiber coupled lasers and produces an aligned array of one or more optical fibers at the output of the cable. The light output from the cable is collimated and relayed to a multiple lens array that spatially divides and shapes the light into an array of beams. The objective lens homogenizes the light by collimating and overlapping the beams into a uniform top hat irradiance distribution in at least one dimension, resulting in the illumination pattern having the required spatial size and desired angular distribution at the illumination plane.