Phosphor Plate Uneven Surface Pattern Enhances Light Extraction
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Solution Overview
Problem
Conventional white LEDs with resin matrices suffer from light degradation and heat dissipation issues, leading to color tone changes and reduced light flux due to low transmittance and reflectance problems, while ceramic sintered bodies offer limited light transmission and light flux extraction.
Innovation Solution
A phosphor plate with a glass matrix and an uneven surface having patterns that occupy 70% to 95% of one surface, minimizing refractive index differences and enhancing light efficiency by improving brightness and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cold cathode fluorescent lamp is used, then long life and high reliability are achieved, but manufacturing complexity and mercury content increase
Solution Approach 1:
The patent extracts and eliminates the mercury component from the lighting system by replacing the cold cathode fluorescent lamp with a fluorescent lamp that uses a fluorescent powder layer excited by UV LEDs, thereby removing the harmful substance while maintaining the lighting function
Solution Approach 2:
The patent employs multiple LEDs emitting at different wavelengths (violet, blue, cyan) that simultaneously serve to excite the fluorescent powder, replacing the single complex cold cathode lamp with a multi-functional LED array that achieves similar lighting output without mercury
2Illumination intensity
If a fluorescent powder layer is applied to the inner wall of the tube, then light emission is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent uses a flexible fluorescent powder coating layer applied to the inner surface of the transparent tube, which can be deposited as a thin film that conforms to the tube's curvature, allowing for adequate coverage without requiring extremely tight tolerances on tube roundness or coating uniformity
Solution Approach 2:
The patent optimizes the particle size, composition, and layer thickness of the fluorescent powder to achieve effective light emission even with variations in coating application, thereby reducing the stringency of manufacturing precision requirements while maintaining illumination performance
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 significantly improves light efficiency and uniformity by maximizing light extraction through diffuse reflection, maintaining desired color coordinates and preventing back-scattering of light, thus addressing the limitations of previous technologies.
Implementation Method 1
a fluorescent powder layer which is formed on an inner wall of the tube and comprises a first fluorescent powder and a second fluorescent powder, each having different peak wavelengths
Implementation Method 2
the first fluorescent powder has a first peak wavelength and the second fluorescent powder has a second peak wavelength, which are different from each other
Data Source
Figure 1~3
Figure 4(a)~4(c)
Figure 5
AI summary
An embodiment of the present invention relates to a phosphor plate, which is a plate-shaped photo-conversion structure in which a phosphor is dispersed inside of a glass matrix, and has an uneven surface comprising at least one type of pattern, formed on at least one surface of the both surfaces of the plate, wherein the pattern occupies 70-95% of the area of the one surface.