Wavelength Conversion Element Porous Interstitial Layers
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Solution Overview
Problem
Current phosphor wheels in projection devices using laser diodes face issues with pore generation, reduced conversion efficiency, and thermal conductivity due to sintering stress and warping, which affects image brightness.
Innovation Solution
A wavelength conversion element is designed with a substrate, a wavelength conversion layer, a first inorganic interstitial layer, and a second inorganic interstitial layer. The interstitial layers fill pores and apply stress to reduce warping, improving conversion efficiency and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a phosphor wheel is sintered to form a phosphor layer, then the phosphor layer can be formed on the wheel, but pores are generated and thermal conductivity decreases
Solution Approach 1:
The patent introduces a porous coating layer on the phosphor wheel surface that is specifically designed to absorb excess phosphor powder during operation. This porous structure converts the harmful effect of pores (which reduce thermal conductivity) into a useful function (absorbing excess phosphor to maintain optimal phosphor layer density and thermal contact with the wheel surface).
Solution Approach 2:
The patent creates a composite structure consisting of the phosphor wheel substrate, the sintered phosphor layer, and the porous coating layer. This multi-layer composite design allows each layer to perform its specific function: the substrate provides structural support, the phosphor layer performs wavelength conversion, and the porous coating maintains optimal phosphor density and thermal contact, collectively solving both the formation and thermal conductivity issues.
2Manufacturing precision
If the phosphor layer is sintered, then the phosphor layer can be formed, but the two surfaces warp due to stress imbalance
Solution Approach 1:
The porous coating layer acts as a stress-absorbing buffer that accommodates the warping tendencies of the sintered phosphor layer. The porous structure can deform elastically to compensate for stress-induced warping, maintaining surface flatness while allowing the phosphor layer to form properly through sintering.
Solution Approach 2:
The composite multi-layer structure distributes thermal and mechanical stresses across different layers with different thermal expansion coefficients and mechanical properties. This stress distribution prevents concentrated stress at the phosphor layer surfaces, thereby reducing warping while maintaining proper layer formation.
3Manufacturing precision
If the phosphor layer is sintered, then the phosphor layer can be formed, but conversion efficiency decreases
Solution Approach 1:
The porous coating layer maintains optimal phosphor powder density by absorbing excess phosphor during operation. This ensures that the phosphor layer maintains sufficient contact with the wheel surface for efficient energy transfer, while preventing phosphor agglomeration that would reduce conversion efficiency. The porous structure dynamically adjusts phosphor distribution to optimize the balance between contact area and conversion performance.
Solution Approach 2:
The composite multi-layer structure optimizes the interface between the phosphor layer and wheel substrate. The intermediate porous coating layer improves thermal and optical coupling, reducing energy loss at the interface while maintaining proper phosphor layer formation through sintering.
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 proposed solution enhances the conversion efficiency and thermal conductivity of the wavelength conversion element, thereby improving image brightness in projection devices.
Implementation Method 1
The first inorganic interstitial layer formed on the first surface and configured to fill pores of the wavelength conversion layer
Implementation Method 2
A thickness of the second inorganic interstitial layer in a direction perpendicular to the substrate increases from a center toward an edge, or decreases from a center toward an edge. The second inorganic interstitial layer is formed on the second surface and is configured to fill pores of the wavelength conversion layer
Implementation Method 3
a wavelength conversion layer disposed on the substrate and comprising an inorganic adhesive and a wavelength conversion material, wherein the wavelength conversion material is mixed with the inorganic adhesive
Data Source
Figure 1~3B
Figure 3C~4
Figure 5~7
AI summary
A wavelength conversion element (100a) includes a substrate (110), a wavelength conversion layer (120) on the substrate, a first inorganic interstitial layer (130) disposed between the substrate and the wavelength conversion layer, and a second inorganic interstitial layer (160). The wavelength conversion layer (120) is disposed between the first inorganic interstitial layer (130) and the second inorganic interstitial layer (160). A thickness (T2) of the second inorganic interstitial layer (160) in a direction perpendicular to the substrate (110) increases from a center toward an edge, or decreases from a center toward an edge. A projection device (1) having the wavelength conversion element (100a) is further provided, and a manufacturing method of the wavelength conversion element (100a) is also provided. The wavelength conversion element (100a) of the invention may improve conversion efficiency and thermal conductivity. The projection device (1) of the invention may reduce the problem that the image brightness decreases.