LED Reflector Layer Structure for Continuous Light Extraction
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Solution Overview
Problem
Existing light emitting device manufacturing methods require high precision adjustments for reflecting material placement, leading to potential discontinuities in the reflecting material layer, which can affect emission efficiency.
Innovation Solution
A method involving the sequential formation of first and second reflecting layers using resins with reflecting materials, where the second reflecting layer is settled using centrifugal force to cover the bottom surface without facing the lateral surfaces of the light emitting element, and a phosphor-containing layer is disposed on top, enhancing light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single resin layer containing reflecting material is injected into the recess and centrifugal force is applied, then the reflecting material layer can be disposed near the bottom surface and lateral surfaces, but high precision adjustment is required and the reflecting material layer may not be continuously disposed
Solution Approach 1:
The reflecting layer is divided into two separate layers: a first reflecting layer formed by injecting resin containing reflecting material into the recess, and a second reflecting layer formed by injecting additional resin containing reflecting material after the light emitting element is mounted. This segmentation allows each layer to be formed with appropriate precision requirements and ensures continuous coverage without requiring high precision adjustment of a single layer
Solution Approach 2:
The first reflecting layer is formed in advance before mounting the light emitting element, creating a preliminary reflecting surface at the bottom and lateral surfaces of the recess. This preliminary action establishes a foundation that reduces the precision requirements for the second layer, ensuring continuous coverage while simplifying the overall manufacturing process
2Productivity
If the reflecting material layer is disposed to cover the bottom surface and lateral surfaces, then light emission efficiency can be improved, but the process requires high precision adjustment which may lead to discontinuities
Solution Approach 1:
The reflecting layer formation process is segmented into two sequential steps: first forming a reflecting layer before element mounting, then forming a second reflecting layer after mounting. This segmentation maintains high light emission efficiency through complete surface coverage while reducing precision adjustment requirements by dividing the complex single-step process into two simpler steps with different precision requirements
3Loss of energy
If the second reflecting layer is formed to cover the bottom surface without facing lateral surfaces of the light emitting element, then light leakage is prevented, but the forming process becomes more complex
Solution Approach 1:
The reflecting layer formation is segmented into two distinct operations: the first reflecting layer covers the bottom and lateral surfaces of the recess, while the second reflecting layer covers the bottom surface and extends up the lateral surfaces. This segmentation allows the second layer to be formed without facing the light emitting element's lateral surfaces, preventing light leakage while keeping each individual layer formation process relatively simple
Solution Approach 2:
Different regions of the recess receive different reflecting layer configurations: the bottom surface receives both first and second reflecting layers for maximum reflection, while the lateral surfaces receive the first reflecting layer and portions of the second reflecting layer. This local quality approach prevents light leakage from the bottom area while avoiding the complexity of forming a single continuous layer with varying thickness
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
This approach ensures continuous and efficient light emission by preventing light leakage and absorption, improving emission efficiency and color distribution of the light emitting device.
Implementation Method 1
settling the second reflecting material in the second resin by a centrifugal force
Data Source
AI summary
A light emitting device includes: a package in which a recess is defined; a light emitting element mounted on a bottom surface defining the recess; a first reflecting layer covering lateral surfaces defining the recess; and a second reflecting layer covering the bottom surface defining the recess, wherein the second reflecting layer is in contact with the first reflecting layer, wherein at least a portion of lateral surfaces of the light emitting element is exposed from the second reflecting layer.