LED Volume Layer for Light Extraction and Beam Spread
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light emitting diodes (LEDs) face challenges in achieving high light extraction efficiency and wide orientation angles, leading to limited beam spread and potential phosphor degradation due to light being concentrated in a vertical direction.
Innovation Solution
A light emitting diode structure featuring a support substrate with a light emitting structure layer, a passivation layer, and a volume layer with a thickness of 1 µm to 20 µm, made of materials like SiO2, SiOx, or Al2O3, which allows light to be emitted upwardly and laterally, preventing concentration and enhancing extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If light emitting structure layer is designed to emit light upwardly, then light extraction efficiency is improved, but light becomes concentrated in vertical direction causing limited beam spread
Solution Approach 1:
The patent introduces a volume layer with specific thickness (greater than electrode thickness) that extends in the vertical dimension, transforming the light emission from a concentrated upward direction to a distributed pattern that includes lateral propagation. This dimensional extension allows light to travel through the volume layer and exit in multiple directions, resolving the contradiction between vertical extraction efficiency and beam spread.
Solution Approach 2:
The patent changes the thickness parameter of the volume layer to be greater than the electrode thickness, which fundamentally alters the light propagation characteristics. This parameter change enables light to traverse the volume layer laterally, converting the emission pattern from vertically concentrated to widely distributed, thus improving both extraction efficiency and beam spread simultaneously.
2Loss of energy
If light is concentrated in vertical direction, then light extraction efficiency is improved, but phosphor degradation occurs due to excessive light concentration
Solution Approach 1:
The volume layer structure extends light propagation into the lateral dimension, distributing the light energy that would otherwise be concentrated vertically. This dimensional redistribution reduces the intensity of light reaching the phosphor while maintaining overall extraction efficiency, preventing phosphor degradation.
Solution Approach 2:
The volume layer acts as an intermediary between the light emitting structure layer and the phosphor. It mediates the light transmission by allowing controlled lateral propagation, thereby reducing excessive vertical light concentration that causes phosphor degradation while preserving useful light extraction.
3Reliability
If electrode thickness is increased, then electrical connection is improved, but volume layer thickness must be increased proportionally maintaining limited beam spread
Solution Approach 1:
The patent establishes a specific parameter relationship where volume layer thickness is greater than electrode thickness. This parameter change decouples the orientation angle from direct proportionality to electrode thickness, allowing the volume layer to provide sufficient lateral light propagation path even when electrode thickness varies, thus improving electrical connection without limiting beam spread.
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 solution improves light extraction efficiency and provides a wider orientation angle, reducing light loss and phosphor degradation, resulting in a more efficient and effective LED package with enhanced beam spread.
Implementation Method 1
the volume layer is disposed on the light emitting structure layer to prevent light generated in the light emitting structure layer from being concentrated in an upper direction, and wherein the volume layer is provided to allow the light generated in the light emitting structure layer to be emitted upwardly and laterally while passing through the volume layer
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
Provided are a light emitting device, a light emitting device package, and a light unit. The light emitting device includes a support substrate, a light emitting structure layer disposed on the support substrate, the light emitting structure layer including a first conductive type semiconductor layer, a second conductive type semiconductor layer, and an active layer disposed between the first conductive type semiconductor layer and the second conductive type semiconductor layer, an electrode electrically connected to the first conductive type semiconductor layer, and a volume layer disposed on the light emitting structure layer, the volume layer having a thickness greater than a thickness of the electrode.