Phosphor Crystal Sheet and Powder Composite for LED Light Conversion
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Solution Overview
Problem
Conventional light-emitting devices face issues with blue-enriched white light due to insufficient heat dissipation and light conversion efficiency, and the use of phosphor crystal structures is costly and not compatible with standard devices.
Innovation Solution
A composite light-emitting device structure incorporating a phosphor crystal sheet and phosphor crystal powders with controlled crystal orientations and rare-earth element doping, where the phosphor crystal powders are sintered to connect with the sheet, increasing the light path and adjusting chromaticity, is employed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If phosphor crystal is used to improve heat dissipation and light conversion rate, then heat dissipation property is improved, but the light transmission path is shorter resulting in blue-enriched white light
Solution Approach 1:
The patent transitions from a single-layer phosphor crystal structure to a multi-layer composite structure consisting of a phosphor crystal sheet layer and a phosphor crystal powder layer. This dimensional expansion allows the light to traverse multiple layers, effectively increasing the total light transmission path length without requiring a single excessively thick crystal layer, thereby solving the blue-enriched white light problem while maintaining effective heat dissipation.
Solution Approach 2:
The patent employs a composite structure combining phosphor crystal sheet and phosphor crystal powder in distinct layers. The phosphor crystal sheet provides efficient heat dissipation and high light conversion rate, while the phosphor crystal powder layer compensates for insufficient light absorption by extending the effective light path. This composite approach integrates the advantages of both materials to achieve balanced thermal management and optical performance.
2Illumination intensity
If thickness of phosphor crystal is increased to increase light transmission path, then light absorption is improved, but the phosphor crystal is not compatible with common light-emitting device specifications and production cost increases
Solution Approach 1:
The patent divides the phosphor crystal structure into multiple segments: a phosphor crystal sheet layer and a phosphor crystal powder layer. This segmentation allows each layer to have optimized thickness independent of the total required light path length. The sheet layer maintains thin profile for device compatibility, while the powder layer extends the effective light path to improve absorption efficiency, avoiding the need for a single thick crystal that would increase cost and reduce compatibility.
Solution Approach 2:
Instead of increasing thickness in one dimension, the patent uses a multi-layer approach that effectively increases the light path through multiple interfaces and layers. The light must pass through both the sheet layer and the powder layer, creating a longer effective path without requiring any single layer to be excessively thick, thus maintaining device compatibility while improving light absorption.
3Temperature
If fluorescent powder layer is replaced by phosphor crystal to improve heat dissipation, then heat dissipation is improved, but light conversion path is shorter resulting in less blue light absorption
Solution Approach 1:
The patent creates a composite phosphor system combining crystal sheet and crystal powder layers. The phosphor crystal sheet provides superior heat dissipation and high light conversion rate due to its single crystal structure, while the phosphor crystal powder layer compensates for the shorter light path by providing additional absorption opportunities through multiple scattering events and extended effective path length, thereby maintaining high overall light conversion efficiency.
Solution Approach 2:
The patent extends the light conversion process from a single-layer structure to a multi-layer composite structure. This dimensional expansion allows the light to interact with phosphor materials in multiple stages: first passing through the crystal sheet for initial conversion and heat dissipation, then traversing the crystal powder layer for additional absorption and conversion opportunities, thereby enhancing overall light conversion efficiency while preserving heat dissipation benefits.
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 configuration enhances light conversion efficiency, heat dissipation, and flexibility in chromaticity adjustment, reducing manufacturing costs while addressing blue-enriched white light issues, achieving a light emission efficiency of at least 150 lumens/watt.
Implementation Method 1
a light-emitting diode emits blue light, such that a portion of the blue light enters a fluorescent-powder layer to generate yellow light or green light
Implementation Method 2
the first phosphor crystal powders are sintered to be connected to each other, and at least a portion of the first phosphor crystal powders is sintered to be connected to the second surface of the first phosphor layer
Data Source
AI summary
A light-emitting device includes a composite structure having a phosphor crystal sheet and phosphor crystal powders on the phosphor crystal sheet. A light-emitting unit of the device is disposed under a side of the phosphor crystal sheet that is opposite to a side of the phosphor crystal powders. A problem of blue-enriched white light may be tackled.