LED Reflection Layer Structure for Low-Loss Wide-Angle Emission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional flip chip type light emitting diodes suffer from significant light loss due to the use of metal reflection layers, which also experience reduced reflectance over time, and require diffusion plates or filters to disperse light, leading to inefficiencies and increased power loss.
Innovation Solution
A light emitting diode design incorporating a first and second insulation reflection layer with distributed Bragg reflectors, and a configuration of multiple light emitting cells connected in series to reduce light loss and increase luminous intensity without the need for diffusion plates or filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If metal reflection layers are used in conventional flip chip type light emitting diodes, then light can be reflected, but significant light loss occurs and reflectance reduces over time
Solution Approach 1:
The patent changes the material parameters of the reflection layer by using insulation reflection layers made of dielectric materials (such as silicon oxide, silicon nitride, or silicon oxynitride) instead of metal materials. This parameter change transforms the reflection mechanism from metallic reflection to dielectric reflection, achieving high reflectance (90% or more) while eliminating the light absorption and oxidation problems inherent in metal layers, thereby reducing light loss and maintaining stable reflectance over time.
Solution Approach 2:
The patent employs composite material structures by combining multiple insulation layers with different refractive indices to form insulation reflection layers. These composite dielectric structures create constructive interference for reflected light waves, enhancing overall reflectance while maintaining durability. The multi-layer composite approach allows optimization of both optical performance and long-term stability.
2Ease of operation
If diffusion plates or filters are used to disperse light, then light can be dispersed, but inefficiencies and increased power loss occur
Solution Approach 1:
The patent extracts and eliminates the need for separate diffusion plates or filters by integrating light dispersion functionality directly into the insulation reflection layer structure. The distributed Bragg reflector design inherently provides light scattering and dispersion through its multi-layer architecture, removing the requirement for additional diffusion components and the associated energy losses they cause.
Solution Approach 2:
The insulation reflection layer serves multiple functions simultaneously: it provides high reflectance, disperses light, and eliminates the need for separate diffusion plates. This multi-functional design consolidates what were previously separate components (reflection layer + diffusion plate) into a single integrated structure, improving overall system efficiency and reducing power loss.
3Illumination intensity
If a single light emitting cell is used, then the structure is simple, but luminous intensity is limited
Solution Approach 1:
The patent divides the light emitting device into multiple independent light emitting cells (first light emitting cell, second light emitting cell, etc.) that can be connected in series. Each cell contains its own light emitting structure with insulation reflection layers. This segmentation allows the total luminous intensity to be the sum of individual cell outputs while maintaining relatively simple individual cell structures that can be manufactured using standard processes.
Solution Approach 2:
The patent combines multiple light emitting cells into a single integrated device with common electrical connections and a unified substrate structure. The series connection of multiple cells multiplies the overall luminous intensity output while sharing common structural elements (substrate, packaging, electrical interconnects), thereby achieving high illumination without proportionally increasing overall device complexity.
4Loss of energy
If insulation reflection layers with distributed Bragg reflectors are used, then light loss is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the parameters of the distributed Bragg reflector by selecting common dielectric materials (silicon oxide, silicon nitride, silicon oxynitride) and standardizing layer thicknesses to achieve quarter-wavelength optical paths. These parameter optimizations allow the complex multi-layer structure to be manufactured using existing semiconductor fabrication processes, reducing the practical manufacturing complexity despite the sophisticated optical design.
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 design effectively disperses light over a wide area, reduces power loss, and enhances luminous efficiency by minimizing light loss through the use of insulation reflection layers and a series connection of cells, while maintaining structural simplicity and miniaturization.
Implementation Method 1
a first insulation reflection layer covering the substrate, the light emitting structure, the transparent electrode, the contact electrode, and the current spreader, having openings exposing portions of the contact electrode and the current spreader, and including a distributed Bragg reflector
Implementation Method 2
a second insulation reflection layer disposed under the substrate, and including a distributed Bragg reflector, in which a reflection band of the second insulation reflection layer is narrower than a reflection band of the first insulation reflection layer
Implementation Method 3
a light emitting structure disposed on the substrate, and including a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer
Implementation Method 4
a transparent electrode disposed on and in ohmic contact with the second conductivity type semiconductor layer
Data Source
AI summary
A light emitting diode is provided to include a substrate; a light emitting structure disposed on the substrate, and including first and second semiconductor layers; a transparent electrode in ohmic contact with the second semiconductor layer; a contact electrode disposed on the first semiconductor layer; a current spreader disposed on the transparent electrode; a first insulation reflection layer covering the substrate, the light emitting structure, the transparent electrode, the contact electrode, and the current spreader, having openings exposing portions of the contact electrode and the current spreader, and including a distributed Bragg reflector; first and second pad electrodes disposed on the first insulation reflection layer and connected to the contact electrode and the current spreader through the openings; and a second insulation reflection layer disposed under the substrate and including a distributed Bragg reflector.