Alignment error modeling and control of a double-sided microlens array during precision glass molding.

Area of Science:

• Optics and Photonics
• Materials Science
• Manufacturing Engineering

Background:

• Double-sided microlens arrays (DSMLAs) offer improved light transmissivity and overcome positioning errors compared to single-sided lenses.
• Precision glass molding (PGM) is a key fabrication method for DSMLAs, but controlling mold core alignment errors remains a significant challenge.
• Existing methods struggle with precise alignment, impacting the optical performance and uniformity of DSMLAs.

Purpose of the Study:

• To develop a novel mold assembly using specific material combinations to enhance mold core alignment accuracy during PGM.
• To establish mathematical and thermal expansion models to predict and minimize DSMLA alignment errors.
• To optimize the mold-sleeve gap for improved DSMLA fabrication precision and performance.

Main Methods:

• Manufactured a mold assembly utilizing materials with nonlinear thermal expansion characteristics.
• Developed a mathematical model for DSMLA alignment error and a thermal expansion model for the mold-sleeve pair.
• Determined the relationship between mold-sleeve gap and maximum DSMLA alignment error to optimize fabrication parameters.

Main Results:

• Achieved a measured DSMLA alignment error of 10.56 μm, closely matching the predicted maximum error.
• Demonstrated high optical performance with 97.81% uniformity in the homogenized beam spot.
• Confirmed that 91.66% of the total area was effectively homogeneous, indicating significant improvement.

Conclusions:

• The proposed novel mold assembly and modeling approach effectively minimizes alignment errors in DSMLA fabrication via PGM.
• Optimizing the mold-sleeve gap based on thermal expansion characteristics is crucial for achieving high-accuracy DSMLA.
• This research presents a viable strategy for enhancing the performance and manufacturing precision of double-sided microlens arrays.