Wide heart-shaped mini-LEDs without a second lens as a large area, ultra-high luminance, and flat light source

Area of Science:

• Optoelectronics
• Materials Science
• Display Technology

Background:

• Increasing demand for high-brightness outdoor and industrial displays.
• Challenges in reducing thermal resistance and preventing lens detachment in traditional LED packaging.
• Need for enhanced light distribution and thermal management in light source packages.

Purpose of the Study:

• To propose and validate a new packaging structure for wide heart-shaped angular light distribution mini-light emitting diodes (WHS mini-LEDs).
• To enhance the light-emitting angle and reduce thermal resistance for high-brightness display applications.
• To address the limitations of secondary optical lenses in LED packaging.

Main Methods:

• Direct chip bonding to an aluminum substrate using a metal eutectic process for minimized thermal resistance.
• Development of a primary optical design for enhanced light-emitting angle.
• Integration of WHS mini-LEDs with quantum dot (QD) film and brightness enhancement film (BEF) in a backlight module (BLM).

Main Results:

• Achieved a total thermal resistance of 6.7 K/W for the WHS mini-LED package.
• Demonstrated that 448 WHS mini-LEDs are sufficient for a 55-inch BLM.
• Attained an average luminance of 2234.2 cd/m², 90% uniformity, and 119.3% NTSC in the liquid crystal module (LCM).

Conclusions:

• The proposed WHS mini-LED packaging structure effectively reduces thermal resistance and enhances light distribution.
• This design provides a competitive solution for large-area, high-brightness, and high-color-saturation outdoor advertising and industrial displays.
• The packaging method offers improved performance and reliability compared to traditional approaches.