Multi-Layered Light Reflective Member for LED Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light emitting devices with resin-based reflective layers face challenges in achieving both high reflectance and reliability due to the need for high content of light reflective fillers, which reduces fluidity and formability, leading to brittle molding and reduced emission efficiency.
Innovation Solution
A multi-layered light reflective member is used, comprising a first layer with a high content of light reflective substance for high reflectance and a second layer with a lower content for maintaining mechanical strength, allowing for improved formability and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light reflective filler is added at a high content to achieve adequate reflectance, then reflectance is improved, but the fluidity of the resin material is reduced, making it hard and resulting in reduced formability and reliability
Solution Approach 1:
The light reflective member is divided into multiple layers with different light reflective filler contents. The first layer (near the LED) has high filler content (40-70 wt%) for maximum reflectance, while subsequent layers have progressively lower filler contents (30-50 wt%, then 10-30 wt%) to maintain resin fluidity and formability. This segmentation allows each layer to optimize for its specific function without compromising the whole structure.
Solution Approach 2:
Different regions of the light reflective member have different filler concentrations optimized for their local requirements. The inner layer near the LED requires high reflectance, so it contains more filler, while outer layers require better mechanical properties and fluidity, so they contain less filler. This local quality variation resolves the contradiction between reflectance and formability.
2Illumination intensity
If a light reflective filler is added at a high content to achieve adequate reflectance, then reflectance is improved, but the resin material becomes brittle, reducing reliability
Solution Approach 1:
The multi-layer structure segments the high filler content requirement from the structural integrity requirement. Only the first layer needs high filler content for reflectance, while subsequent layers with lower filler content provide mechanical strength and reliability, preventing the entire structure from becoming brittle.
Solution Approach 2:
The light reflective member uses a composite structure combining resin and light reflective filler in varying proportions across layers. This composite approach allows optimization of optical properties in the first layer while maintaining mechanical properties in outer layers, achieving both high reflectance and reliability.
3Illumination intensity
If a single-layer reflective member with high light reflective filler content is used, then reflectance is improved, but light occasionally passes through and leaks out, reducing emission efficiency
Solution Approach 1:
The reflective member is segmented into multiple layers, each contributing to light reflection. The high filler content in the first layer provides strong reflection, while subsequent layers with moderate filler content provide additional reflection barriers, collectively preventing light leakage more effectively than a single layer.
Solution Approach 2:
Instead of using one extremely high filler content layer, the invention uses multiple layers with progressively lower filler contents. This partial action approach distributes the reflection function across layers, achieving complete light blocking without the downsides of excessive filler in a single layer.
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 multi-layered structure enhances frontal luminance and reliability of light emitting devices by optimizing reflectance and mechanical properties without compromising formability.
Implementation Method 1
a first layer, which is disposed on the inner side, the semiconductor light emitting element side, and made of a light-transmissive resin containing a light reflective substance
Data Source
AI summary
A light emitting device includes: a light emitting element; a wavelength conversion member disposed on or above an upper surface of the light emitting element; a light-transmissive member disposed on an upper surface of the wavelength conversion member; and a light reflective member disposed on each side surface of the light emitting element, the wavelength conversion member, and the light-transmissive member, wherein an upper surface of the light reflective member is coplanar with an upper surface of the light-transmissive member, and wherein each of the upper surface of the light reflective member and the upper surface of the light-transmissive member is a cut surface.