Single Crystal Phosphor Light Emitting Device Thermal Management
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Solution Overview
Problem
Current light emitting devices using blue light emitting elements and yellow phosphors face inefficiencies in light emission due to scattering and thermal conductivity issues, leading to reduced light output and increased heat management challenges.
Innovation Solution
Incorporating a single crystal or polycrystalline fluorescent material represented by the formula Y3-x-yLxMyAl5O12, where L is Gd or Lu, and M is Ce, Tb, Eu, Yb, Pr, or Sm, with specific composition and structure optimizations, including anti-reflection coatings and textured surfaces, to enhance light absorption and emission efficiency while improving thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If yellow phosphor is used to convert blue light to white light, then light emission is achieved, but light scattering occurs reducing light output efficiency
Solution Approach 1:
The patent changes the physical state parameter of the phosphor material from conventional powder form to single crystal form. This parameter change eliminates grain boundaries and reduces light scattering, thereby improving light output efficiency while maintaining the light conversion function.
Solution Approach 2:
The patent uses a composite structure consisting of a single crystal phosphor layer combined with a blue light-emitting element. The single crystal phosphor material (such as Lu3Al5O12:Ce) works synergistically with the blue LED to produce high-efficiency white light, reducing energy loss from scattering.
2Temperature
If conventional phosphor materials are used, then light emission is achieved, but thermal conductivity is poor leading to heat management challenges
Solution Approach 1:
The patent changes the thermal conductivity parameter by transitioning from conventional phosphor materials to single crystal phosphor materials such as Lu3Al5O12:Ce. Single crystal structures inherently possess superior thermal conductivity compared to polycrystalline or amorphous phosphors, enabling effective heat dissipation from the blue LED while maintaining operational temperature control.
3Illumination intensity
If blue light emitting element and yellow phosphor are combined, then white light is emitted, but color scattering occurs reducing light quality
Solution Approach 1:
The patent changes the optical parameter of the phosphor material by using single crystal phosphors with controlled emission wavelengths. The single crystal Lu3Al5O12:Ce phosphor emits yellow light with a specific wavelength range that, when combined with blue LED light, produces high-quality white light with reduced color scattering and improved color rendering.
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 results in reduced light loss and improved color scattering, enabling high-power light emitting devices with enhanced thermal management and efficiency in light emission, suitable for high-output applications.
Implementation Method 1
the fluorescent film absorbs the blue light and emits light having a wavelength different from that of the blue light
Data Source
AI summary
A light emitting device including a light emitting element for emitting blue light; and a fluorescent film including a single crystal fluorescent material or a polycrystalline fluorescent material, wherein the fluorescent film absorbs the blue light and emits light having a wavelength different from that of the blue light, wherein the fluorescent film faces a surface of the light emitting element, and the fluorescent material included in the fluorescent film is represented by the following Formula (1):Y3-x-yLxMyAl5O12 wherein L is Gd or Lu, and M is Ce, Tb, Eu, Yb, Pr, Tm, or Sm, 0≤x≤2.999, and 0.001≤y≤0.1.