Microlens Array Diffuser for Uniform Illumination Edge Control
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Solution Overview
Problem
Existing optoelectronic modules face inefficiencies in diffuse illumination due to non-uniform light distribution, high-frequency components, and lack of high-contrast edges, which affect precision and resource utilization.
Innovation Solution
A microlens array diffuser with varying microlens periodicity-influencing characteristics and surface profiles is used to generate diffuse illumination with uniform or gradually changing light distribution and high-contrast edges, minimizing high-frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple diffusive surface (e.g., sand-blasted surface) is used as a diffuser, then the structure is simple and easy to manufacture, but the illumination does not terminate with high-contrast edges and exhibits high back scattering resulting in reduced operational efficiency
Solution Approach 1:
The patent changes the physical parameters of the diffuser by using a microlens array with specifically designed lens profiles (e.g., aspheric surfaces, varying refractive indices) rather than a simple diffusive surface. This parameter change enables the illumination to terminate with high-contrast edges while minimizing back scattering, thereby improving operational efficiency without sacrificing manufacturability through established microlens fabrication techniques
Solution Approach 2:
The patent employs a composite structure where microlenses are integrated into a diffuser substrate. This composite approach combines the light-guiding properties of microlenses with the diffusive characteristics of the substrate material, achieving both high-contrast edge termination and reduced back scattering while maintaining ease of manufacture through composite material processing
2Manufacturing precision
If a microlens array diffuser with uniform periodicity is used, then the light distribution can be controlled, but diffractive artifacts and interference artifacts are generated resulting in non-optimal performance
Solution Approach 1:
The patent introduces asymmetry and aperiodicity into the microlens array design by varying the periodicity of microlenses across the array or using non-uniform spacing patterns. This aperiodic arrangement disrupts the formation of regular interference patterns and diffractive artifacts while maintaining controlled light distribution through carefully designed local lens parameters
Solution Approach 2:
The patent applies local quality by allowing different regions of the microlens array to have different periodicity characteristics. Each local region can be optimized for specific light distribution requirements while the overall aperiodic structure minimizes global interference artifacts, achieving both precise local control and reduced harmful effects
3Productivity
If the field of illumination is matched to the field of view, then resource efficiency is improved, but the illumination must terminate abruptly requiring high-contrast edges which is difficult to achieve with conventional diffusers
Solution Approach 1:
The patent utilizes the curved surfaces of microlenses to naturally create abrupt illumination termination with high-contrast edges. The spherical or aspheric lens profiles focus and redirect light rays to terminate precisely at the field of illumination boundary, achieving the required edge contrast through geometric optics rather than requiring complex manufacturing processes
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 solution provides efficient diffuse illumination with high-contrast edges and reduced high-frequency components, enhancing the precision and resource utilization of optoelectronic modules.
Implementation Method 1
A microlens array diffuser can overcome some of the limitations of the diffuser described above. For example, the profile of each microlens within the microlens array diffuser can be configured to produce a precisely controlled light distribution
Implementation Method 2
Generally, diffractive artifacts are generated from each microlens within the microlens array diffuser (e.g., at the edges of each microlens) as a result of the relatively small clear aperture size of the microlenses
Implementation Method 3
Further, interference artifacts, generally, are generated from the periodic arrangement of the microlenses within such a microlens array diffuser
Data Source
Figure 1A~1C
Figure 2
AI summary
A microlens array diffuser operable to generate a substantially diffuse illumination includes an array of microlenses, wherein each microlens has a respective periodicity-influencing characteristic and a respective surface profile. The array of microlenses includes at least two microlenses having respective periodicity-influencing characteristics that differ from one another and having respective surface profiles that differ from one another. Each surface profile is configured to generate a substantially equal field of illumination. The microlens array diffuser can be integrated as part of an illuminator operable to generate substantially diffuse illumination.