High-Uniformity Planar Mini-Chip-Scale Packaged LEDs with Quantum Dot Converter for White Light Source

Area of Science:

• Optoelectronics
• Materials Science

Background:

• Improving brightness uniformity in backlight units (BLUs) is crucial for display quality.
• Mini-chip-scale packaged light-emitting diodes (mini-CSPLEDs) offer compact lighting solutions.

Purpose of the Study:

• To develop a novel direct-lit mini-CSPLED BLU with enhanced brightness uniformity.
• To investigate the impact of mini-CSPLED emission angles and quantum dot (QD) film thickness on BLU performance.

Main Methods:

• Fabrication of mini-CSPLEDs with varying emission angles (120°, 150°, 180°) using a chip-scale package (CSP) process.
• Integration of QD films with different thicknesses (60, 90, 150 μm) into the BLU.
• Analysis of BLU brightness uniformity and chromaticity with different mini-CSPLED configurations and QD film thicknesses.

Main Results:

• A 180° mini-CSPLED exhibits a wider emission angle, contributing to a planar light source and improved BLU uniformity.
• Increasing QD film thickness from 60 μm to 150 μm enhances BLU brightness.
• Optimal performance achieved with a 180° mini-CSPLED BLU and 150-μm-thick QD films, resulting in 86% brightness uniformity.

Conclusions:

• The proposed direct-lit mini-CSPLED BLU with optimized emission angles and QD film thickness significantly improves brightness uniformity.
• Wider emission angle mini-CSPLEDs are effective in reducing the number of LEDs required for uniform illumination.
• This technology offers a pathway to more efficient and uniform display backlighting.