Miniaturized Light Emitting Device with Cavity Wavelength Conversion
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Solution Overview
Problem
There is a demand for miniaturized light emitting devices with thin outlines, particularly for side-view applications, where existing technologies struggle to achieve both miniaturization and efficient light output while maintaining mechanical strength and reliability.
Innovation Solution
A light emitting device is designed with a substrate having connecting terminals and a wavelength-conversion layer, where the encapsulating member forms a cavity around the light emitting element, allowing for the conversion of emitted light and enhancing light extraction efficiency without a package, using a combination of materials and structures to ensure mechanical strength and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the light emitting device is miniaturized with a thin outline, then the device size is reduced, but the mechanical strength and reliability deteriorate
Solution Approach 1:
The device is divided into distinct functional layers: a substrate layer for mechanical support, a light emitting element layer, and a wavelength conversion layer. This segmentation allows each layer to be optimized independently - the substrate provides strength while the overall device achieves miniaturization.
Solution Approach 2:
The device employs composite structures combining different materials with complementary properties. The substrate uses materials with high mechanical strength, while the wavelength conversion layer uses phosphor materials. This composite approach enables the thin device to maintain reliability through material property optimization rather than simply increasing size.
2Volume of moving object
If the package structure is removed for miniaturization, then the device size is reduced, but the environmental resistance and reliability worsen
Solution Approach 1:
The traditional separate packaging structure is extracted and removed. Instead of adding a package around the light emitting element, the protective and functional features are integrated directly into the device structure itself, eliminating the need for additional protective housing.
Solution Approach 2:
The substrate serves multiple functions simultaneously: it provides mechanical support, acts as a mounting platform for the light emitting element, and serves as the base for the wavelength conversion layer. This multi-functionality replaces what would traditionally require separate packaging components.
3Use of energy by moving object
If the wavelength conversion layer is placed directly on the light emitting element, then the light extraction efficiency is improved, but the phosphor resistance to environmental exposure must be sufficient
Solution Approach 1:
The wavelength conversion layer is positioned in direct contact with the light emitting element where the optical interaction is most effective. This localized placement optimizes light extraction efficiency at the critical interface between the LED and the phosphor material.
Solution Approach 2:
Phosphor materials with high environmental resistance are selected and combined with the light emitting element. This composite material approach ensures that the wavelength conversion layer can function effectively in direct contact with the LED while resisting degradation from operational environmental factors.
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 enables the production of thin, miniaturized light emitting devices with improved light output and reliability, achieving efficient light extraction and environmental resistance through the use of a wavelength-conversion layer and optimized substrate and encapsulating member design.
Implementation Method 1
a wavelength-conversion layer in the cavity, the wavelength-conversion layer being capable of converting that converts the wavelength of light emitted by the light emitting element
Data Source
AI summary
A light emitting device including a light emitting element including an element substrate and semiconductor layers formed thereon, an encapsulating member that covers the sides of the light emitting element and forms a cavity at the upper surface of the light emitting element, and a wavelength-conversion layer in the cavity. The wavelength-conversion layer being capable of converting that converts the wavelength of light emitted by the light emitting element. The wavelength-conversion layer includes a first wavelength-conversion sub layer which is disposed at the upper surface of the light emitting element, and a second wavelength-conversion sub layer which is disposed on the first wavelength-conversion sub layer. The first wavelength-conversion sub layer includes first phosphors having a first resistance to environmental exposure, and the second wavelength-conversion sub layer includes second phosphors having a second resistance which is higher than that of the first wavelength-conversion sub layer.