Semicircular Phosphor Layers with Resin Intermediary for LED Efficiency
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Solution Overview
Problem
Conventional white-color Light Emitting Devices (LEDs) face efficiency degradation due to thermal quenching and reabsorption issues, particularly in high-temperature ranges, which affects luminous efficiency and color rendering.
Innovation Solution
A light emitting device design featuring a blue LED, a semicircular red phosphor layer, and a transparent resin intermediate layer, where the radius of the red phosphor layer and the intermediate layer are optimized to suppress reabsorption of green light, maintaining high luminous efficiency and color accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple phosphors are used to achieve high color rendering and high color gamut, then color quality is improved, but luminous efficiency is degraded by reabsorption between phosphors
Solution Approach 1:
A transparent resin intermediate layer is introduced between the red phosphor layer and green phosphor layer to prevent direct optical interaction. This intermediary layer blocks the green light emitted by the green phosphor from being reabsorbed by the red phosphor, thereby maintaining high luminous efficiency while preserving the color rendering benefits of using multiple phosphors.
2Power
If high-power LED is used to increase output, then power is improved, but thermal quenching occurs at high temperatures degrading emission intensity
Solution Approach 1:
The transparent resin intermediate layer serves as a thermal and optical buffer between phosphor layers, reducing thermal coupling effects. This allows the system to maintain higher emission intensity even when operated at high power levels, as the intermediate layer helps manage heat distribution and reduces thermal quenching in the phosphor materials.
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 design enhances luminous efficiency and color homogeneity by minimizing reabsorption and thermal quenching, maintaining high performance even at elevated temperatures.
Implementation Method 1
a red phosphor layer formed on the light emitting element, the red phosphor layer including a red phosphor
Implementation Method 2
a green phosphor layer formed on the transparent resin intermediate layer, the green phosphor layer including a green phosphor
Implementation Method 3
minimizing reabsorption and thermal quenching
Implementation Method 4
When the temperature rise is generated, generally emission intensity of the phosphor is degraded to generate so-called thermal quenching
Data Source
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AI summary
A light emitting device according to one embodiment includes a board; a light emitting element mounted on the board, emitting light having a wavelength of 250 nm to 500 nm; a red fluorescent layer formed on the element, including a red phosphor expressed by equation (1) , having a semicircular shape with a diameter r; M1-x1Eux1aSibAlOcNd (In the equation (1), M is an element that is selected from IA group elements, IIA group elements, IIIA group elements, IIIB group elements except Al (Aliminum) , rare-earth elements, and IVB group elements), an intermediate layer formed on the red fluorescent layer, being made of transparent resin, having a semicircular shape with a diameter D; and a green fluorescent layer formed on the intermediate layer, including a green phosphor, having a semicircular shape. A relationship between the diameter r and the diameter D satisfies equation (2): 2.0rμm≤D≤r+1000μm.