Wavelength Conversion Layer Structure for Flat, Bright Projectors
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Solution Overview
Problem
Current phosphor wheels in projection devices using laser diodes suffer from reduced conversion efficiency and thermal conductivity due to pore generation and stress-induced warping, leading to decreased image brightness.
Innovation Solution
A wavelength conversion element with a substrate, a wavelength conversion layer, and a first inorganic interstitial layer, where the wavelength conversion layer is mixed with an inorganic adhesive and the interstitial layer is disposed between the conversion layer and the substrate, with a thickness distribution that increases or decreases from the center to the edge, improving surface flatness and reducing warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the phosphor layer is sintered to improve material density, then the conversion efficiency is improved, but the two surfaces will warp due to stress imbalance
Solution Approach 1:
The patent applies parameter changes by controlling the thickness distribution of the transparent adhesive layer. By making the adhesive layer thickness non-uniform (thinner at edges, thicker at center), it compensates for the warping stress generated during sintering, maintaining surface flatness while preserving conversion efficiency.
Solution Approach 2:
The transparent adhesive layer serves as an intermediary between the phosphor wheel and the housing. This intermediate layer absorbs and distributes the thermal and mechanical stresses, preventing direct stress transmission that would cause warping while maintaining the functional contact needed for heat dissipation and structural support.
2Reliability
If the phosphor layer is sintered to improve material density, then the conversion efficiency is improved, but the thermal conductivity decreases due to pore generation
Solution Approach 1:
The patent uses composite materials by combining the phosphor wheel material with a transparent adhesive layer having different thermal and optical properties. This composite structure allows the phosphor layer to maintain high conversion efficiency while the adhesive layer provides alternative thermal conduction pathways, compensating for the thermal conductivity reduction caused by sintering pores.
3Quantity of substance
If the phosphor layer is made thinner to reduce weight, then the manufacturing cost is reduced, but the conversion efficiency decreases
Solution Approach 1:
The patent applies local quality by creating a non-uniform adhesive layer thickness distribution rather than uniformly thinning the phosphor layer. This allows the phosphor layer to maintain optimal thickness for conversion efficiency in critical areas while reducing overall material quantity, as the adhesive layer compensation enables thinner phosphor regions to still achieve desired 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
Enhances conversion efficiency and thermal conductivity, thereby reducing the issue of decreased image brightness in projection devices.
Implementation Method 1
a wavelength conversion layer and a first inorganic interstitial layer, wherein the wavelength conversion layer is disposed on the substrate, the wavelength conversion layer comprises an inorganic adhesive and a wavelength conversion material, and the wavelength conversion material is mixed with the inorganic adhesive
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A wavelength conversion element (100) includes a substrate (110), a wavelength conversion layer (120), and a first inorganic interstitial layer (130). The wavelength conversion layer (120) is disposed on the substrate (110). The wavelength conversion layer (120) includes an inorganic adhesive (121) and a wavelength conversion material (122), and the wavelength conversion material (122) is mixed with the inorganic adhesive (121). The first inorganic interstitial layer (130) is disposed between the wavelength conversion layer (120) and the substrate (110). A projection device (1) having the wavelength conversion element (100) is further provided, and a manufacturing method of the wavelength conversion element (100) is also provided. The wavelength conversion element (100) manufactured by using the manufacturing method 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.