Asymmetric Hexagonal Microlens Array for Optical Beam Homogenization
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Solution Overview
Problem
Existing optical beam homogenizers struggle to effectively homogenize beams with asymmetric intensity distributions, often resulting in output shapes outside the desired hexagonal distribution due to limited angular acceptance.
Innovation Solution
The use of a first hexagonal microlens array with hexagonal clear apertures and a second hexagonal microlens array with non-hexagonal clear apertures, such as rectangular or elliptical, spaced at a focal length of the first array, to refract and homogenize the optical beam.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a traditional beam homogenizer is used, then the beam intensity distribution is homogenized, but the output shape becomes distorted when the input beam has asymmetric intensity distribution
Solution Approach 1:
The patent applies asymmetry by using a first microlens array with asymmetric lenslet spacing (different pitch in x and y directions) that matches the asymmetric intensity distribution of the input beam. This asymmetric configuration allows the homogenizer to properly distribute asymmetric input intensity while maintaining a desired symmetric hexagonal output shape, resolving the contradiction between homogenization and shape preservation.
Solution Approach 2:
The patent changes the geometric parameters of the microlens array, specifically using non-uniform pitch values (Px ≠ Py) to create asymmetric lenslet spacing. This parameter change allows the system to accommodate asymmetric input beams and produce both homogenized intensity distribution and controlled output shape simultaneously.
2Manufacturing precision
If beam conditioning systems are added to homogenize the beam, then the intensity distribution becomes more uniform, but the system complexity, cost, and size increase
Solution Approach 1:
The patent segments the optical system into a single integrated microlens array component with asymmetric lenslet spacing, rather than using multiple separate beam conditioning elements. This segmentation into one optimized component achieves homogenization while reducing overall system complexity, cost, and size.
Solution Approach 2:
The asymmetric microlens array performs multiple functions simultaneously: it homogenizes the intensity distribution, controls the output beam shape, and accommodates asymmetric input beams. This multi-functionality in a single component reduces the need for additional separate beam conditioning elements, thereby reducing system complexity.
3Shape
If a homogenizer with limited angular acceptance is used, then the output shape is maintained, but asymmetric input beams produce output outside the desired shape
Solution Approach 1:
The patent modifies the geometric parameters of the microlens array, specifically using asymmetric pitch values and varying lenslet orientations, to expand the angular acceptance range. This allows the homogenizer to accommodate asymmetric input beams with different divergence angles while still producing the desired consistent output shape.
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 configuration allows for the homogenization of asymmetric optical beams, achieving a symmetric hexagonal output distribution and improving the intensity uniformity across the beam, even for high power laser diode arrays.
Implementation Method 1
A first hexagonal microlens array (10) includes a plurality of lenslets (12). Each lenslet (12) has a hexagonal clear aperture. A second hexagonal microlens array (20) is spaced away from the first hexagonal microlens array (10) at a focal length of the first hexagonal microlens array (10)
Data Source
AI summary
An optical beam homogenizer includes a first hexagonal microlens array having a plurality of hexagonal lenslets. Each lenslet has a hexagonal clear aperture. A second hexagonal microlens array is spaced away from the first hexagonal microlens array at a focal length of the first hexagonal microlens array and has a plurality of hexagonal lenslets. Each lenslet in the second hexagonal microlens array has a non-hexagonal clear aperture.