Homogenized LED-illumination using microlens arrays for a pocket-sized projector

Area of Science:

• Optics and Photonics
• Micro-optics Engineering
• Display Technology

Background:

• Miniaturization of projection systems is crucial for portable electronic devices.
• Existing pocket-sized projectors often face limitations in optical performance and size.

Purpose of the Study:

• To design and fabricate an ultra-miniature LED-based Digital Micromirror Device (DMD) projector.
• To develop a compact homogenizer to reduce system size and improve optical efficiency.
• To evaluate the optical performance of the developed projector.

Main Methods:

• A compact homogenizer comprising a double-side microlens array and two condensers was designed.
• The double-side microlens array (124 x 146) was fabricated using backside alignment and hot embossing.
• Optical performance metrics including uniformity, total throughput, color difference, and LED alignment tolerance were measured.

Main Results:

• The ultra-mini projector achieved dimensions of 75 mm x 67 mm x 42 mm.
• The homogenizer effectively reduced system track length and controlled ray angles.
• The projector demonstrated higher uniformity and total throughput compared to current pocket-sized projectors.

Conclusions:

• The proposed compact homogenizer enables the development of ultra-miniature DMD projectors.
• The fabricated projector exhibits enhanced optical performance suitable for portable applications.
• This work contributes to advancements in compact display and projection technologies.