LED Array Package With Reflective Die Attach for Lumen Recovery
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Solution Overview
Problem
Vertical LEDs experience a 20% lumen drop in LED chip-on-board configurations due to light absorption effects when used as a direct replacement for lateral LEDs, making it difficult to optimize their performance without additional modifications.
Innovation Solution
The use of a translucent substrate and a reflective die attach material surrounding the vertical LEDs in an array design, which reduces light absorption between LEDs, achieving a light output similar to conventional lateral LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If vertical LEDs are used as a drop-in replacement for lateral LEDs in array packages, then the LED configuration is simplified and vertical LED performance advantages are utilized, but light absorption effects between LEDs cause a 20% lumen drop
Solution Approach 1:
A reflective adhesive material is introduced as an intermediary substance between adjacent vertical LEDs in the array. This reflective material redirects light that would otherwise be absorbed by neighboring LEDs back toward the desired emission direction, thereby maintaining high light output while preserving the simplified vertical LED configuration.
2Ease of manufacture
If vertical LEDs are used without additional optimization, then the manufacturing process is simplified, but light absorption effects reduce light output by 20%
Solution Approach 1:
The optical properties of the adhesive material are changed from conventional non-reflective formulations to specifically reflective formulations. This parameter change in the adhesive material's reflectivity enables the system to maintain high light output while keeping the manufacturing process relatively simple, as the same basic assembly steps are used but with a modified material property.
3Ease of manufacture
If conventional die attach material is used with vertical LEDs, then the manufacturing process is straightforward, but light absorption between LEDs reduces overall lumens
Solution Approach 1:
The adhesive material is designed with reflective properties that convert the potentially harmful light absorption effect into a beneficial reflection effect. Light that would normally be absorbed by adjacent LEDs is instead reflected back into the emission path, turning what was previously a loss mechanism into a light-enhancing mechanism while maintaining straightforward manufacturing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The combination of a translucent substrate and reflective die attach material increases light output by 10-20% lumens, effectively addressing the absorption issues and making vertical LEDs a suitable replacement for lateral LEDs in chip-on-board configurations.
Implementation Method 1
a reflective die attach material extending along the one or more side walls of the light emitting die
Implementation Method 2
The light emitting die includes a translucent carrier substrate
Data Source
AI summary
Various aspects of a light emitting apparatus includes a substrate. Various aspects of the light emitting apparatus include a light emitting die arranged on the substrate. The light emitting die includes one or more side walls. Various aspects of the light emitting apparatus include a reflective die attach material extending along the one or more side walls of the light emitting die.