LED Array Package With Reflective Die Attach for Lumen Retention
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Solution Overview
Problem
Vertical LEDs experience a significant lumen drop when used as a replacement for lateral LEDs due to light absorption effects, making them difficult to integrate without additional optimization.
Innovation Solution
The use of a translucent substrate and a reflective die attach material surrounding the vertical LEDs in an array design to minimize light absorption, enhancing light output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If vertical LEDs are used as drop-in replacement for lateral LEDs, then device complexity is reduced, but light output decreases by 20% due to light absorbing effects
Solution Approach 1:
A translucent carrier substrate is introduced as an intermediary between the vertical LED chips and the mounting board. This carrier substrate mediates the light transmission by allowing light to pass through the mounting board rather than being absorbed, thereby resolving the contradiction between simplified device structure and maintained light output intensity
Solution Approach 2:
The mounting board is designed with specific optical parameters - it is made translucent rather than opaque, and its thickness and material composition are optimized to transmit light effectively. This parameter change in the mounting board's optical properties enables vertical LEDs to maintain high light output while keeping the device structure simple
2Use of energy by moving object
If conventional lateral LEDs are replaced by vertical LEDs, then conversion efficiency is improved, but light absorption between LEDs causes lumen drop
Solution Approach 1:
The mounting board, which could potentially absorb light, is instead designed to be translucent and act as a light guide. The light that would have been absorbed is now transmitted through the board to adjacent LEDs, converting a potential loss into a beneficial light distribution mechanism that maintains overall lumen output
Solution Approach 2:
The light propagation path is extended into the vertical dimension by using the thickness of the translucent mounting board as an additional light transmission path. This dimensional approach allows light to travel through the board thickness rather than being absorbed in the planar direction, reducing lumen drop while preserving the high conversion efficiency of vertical LEDs
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 up to 20%, achieving performance similar to conventional lateral LEDs.
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.