Dual-Layer LED Packaging for Radiation Pattern Control
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Solution Overview
Problem
Conventional light-emitting diodes (LEDs) face challenges in miniaturization and reduction in thickness while maintaining light output efficiency, as they often require convex lenses, diffraction gratings, or shielding members that can hinder miniaturization and reduce efficiency.
Innovation Solution
A light-emitting device with a first sealing material layer covering the LED element and a second sealing material layer surrounding the first layer, where the refractive indices of the two layers are different, allowing for control of the radiation pattern without the need for additional components like convex lenses or diffraction gratings, enabling miniaturization and maintaining light output efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a convex lens is used to control radiation pattern, then the radiation pattern can be controlled, but the miniaturization and reduction in thickness of the light-emitting device becomes difficult
Solution Approach 1:
The patent extracts and eliminates the convex lens from the system by using the LED chip's own packaging structure (epoxy resin and silicone resin layers with different refractive indices) to perform the radiation pattern control function, thereby removing the need for separate optical components and enabling miniaturization
Solution Approach 2:
The packaging structure serves multiple functions: it protects the LED chip, provides mechanical support, and controls the radiation pattern through refractive index differences between layers, eliminating the need for separate dedicated optical components
2Illumination intensity
If a diffraction grating is used to control radiation pattern, then the radiation pattern can be controlled, but the light output efficiency decreases due to unused high-order diffracted light
Solution Approach 1:
The patent replaces the diffraction grating's optical diffraction mechanism with a refraction-based system using layers of materials with different refractive indices, which controls radiation pattern without generating unwanted high-order diffracted light and maintains higher light output efficiency
3Illumination intensity
If a shielding member is used to control radiation pattern, then the radiation pattern can be controlled, but the light output efficiency decreases due to blocked light
Solution Approach 1:
The patent changes the refractive index parameter of the packaging materials (using epoxy resin with refractive index of 1.5 and silicone resin with refractive index of 1.4) to control light propagation and radiation pattern, allowing light to pass through without being blocked while still achieving the desired radiation control
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 allows for the miniaturization and thinning of LEDs while preventing a decrease in light output efficiency, enabling applications such as spotlights and general illumination with controlled radiation patterns.
Implementation Method 1
a refractive index of the first sealing material layer is different from that of the second sealing material layer... the radiation pattern from a light-emitting element can be controlled by controlling each refractive index of a plurality of sealing material layers
Data Source
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AI summary
A light-emitting device (1) having a base (10) and a light-emitting element (11) placed on the base (10) includes a first sealing material layer (12) covering the light-emitting element (11) and a second sealing material layer (13) surrounding a side surface of the first sealing material layer (12), wherein the refractive index of the first sealing material layer (12) and the refractive index of the second sealing material layer (13) are different from each other. The light-emitting device (1) is capable of controlling a radiation pattern from the light-emitting element (11) by controlling the refractive index of the first sealing material layer (12) and the refractive index of the second sealing material layer (13). This can facilitate the miniaturization and reduction in thickness of the light-emitting device (1), and prevent the decrease in a light output efficiency of the light-emitting device (1).