Surface topology and functionality of freeform microlens arrays

Area of Science:

• Optics and Photonics
• Optical Engineering
• Materials Science

Background:

• Nonsymmetric (freeform) optical components offer significant advantages in imaging and nonimaging systems.
• Freeform microlens arrays (FMLAs) are crucial for miniaturization and cost reduction in optical devices.
• Characterizing FMLAs presents challenges in design, manufacturing, and quality assessment.

Purpose of the Study:

• To present an innovative and efficient characterization strategy for assessing the quality of FMLAs.
• To enable rapid and accurate evaluation of FMLA performance.
• To address the challenges associated with FMLA characterization.

Main Methods:

• Surface topology of FMLAs precisely measured and represented using nonuniform rational basis-spline (NURBS).
• Optical response predicted through ray-tracing simulations based on measured surface topology.
• Illuminance levels analyzed using a logarithmic scale for improved low-light level representation.

Main Results:

• Excellent agreement between predicted optical response and experimental measurements for reliably measured surface topology.
• Logarithmic scale illuminance levels provide a better match to human visual perception, especially at low light.
• The proposed method demonstrates the potential to accelerate the FMLA manufacturing process.

Conclusions:

• The developed characterization strategy offers a fast and accurate method for assessing FMLA quality.
• NURBS modeling and ray-tracing simulations are effective tools for predicting FMLA optical performance.
• This approach can help overcome current limitations in FMLA manufacturing, promoting wider adoption.