Segmented Reflective Layer for Laser Phosphor Wheel Thermal Management
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Solution Overview
Problem
Existing phosphor wheels used in projection apparatuses with laser diode light sources face issues with high-temperature deterioration due to silicone-based wavelength conversion layers, leading to reduced luminous efficiency and reliability, and have high manufacturing costs when using sintering processes.
Innovation Solution
A wavelength conversion module with a substrate featuring a reflective layer having two first reflective regions and a second reflective region, where the second region is positioned between the first regions and closer to the substrate, preventing high-energy laser spots from concentrating on specific areas of the wavelength conversion layer, thus reducing thermal stress and maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single-type reflective layer is used in the phosphor wheel, then the manufacturing process is simple, but the laser energy concentrates on specific areas causing high-temperature deterioration and burning of the silicone-based wavelength conversion layer
Solution Approach 1:
The reflective layer is divided into multiple regions with different reflectivity characteristics. The patent divides the reflective layer into a first reflective region with first reflectivity and a second reflective region with second reflectivity, where the reflectivity values differ between regions. This segmentation prevents laser energy from concentrating on a single area, distributing the thermal load across different regions with varying reflective properties, thereby preventing burning and deterioration of the wavelength conversion layer.
Solution Approach 2:
Different regions of the reflective layer are assigned different optical properties (reflectivity values) to address local thermal management needs. The first reflective region and second reflective region have distinct reflectivity characteristics tailored to their specific positions and functional requirements, allowing optimized local heat distribution and preventing hot spots that would cause deterioration.
2Reliability
If phosphor in glass (PIG) or phosphor in ceramic (PIC) sintering process is used, then the resistance to high-temperature deterioration is improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent changes the optical parameters (reflectivity values) of different regions in the reflective layer to achieve effective thermal management. By adjusting the reflectivity parameters of the first and second reflective regions, the system distributes laser energy appropriately without requiring expensive sintering processes like PIG or PIC, thus maintaining cost-effectiveness while improving reliability.
3Device complexity
If the wavelength conversion layer is positioned close to the substrate, then the manufacturing complexity is reduced, but the laser spot concentrates energy causing burning and deterioration of the wavelength conversion layer
Solution Approach 1:
The reflective layer is segmented into multiple regions with different reflectivity characteristics positioned at different locations. This segmentation allows the system to manage laser energy distribution effectively even when the wavelength conversion layer is close to the substrate, preventing energy concentration and subsequent burning without increasing structural complexity.
Solution Approach 2:
Different regions of the reflective layer are assigned specific reflectivity properties to address local energy concentration issues. The first reflective region and second reflective region have tailored optical characteristics that prevent laser-induced burning at critical locations while maintaining the overall compact structure.
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
This configuration enhances the reliability and conversion efficiency of the wavelength conversion module, preventing deterioration and burning, while also lowering manufacturing costs by distributing energy evenly across the reflective and wavelength conversion layers.
Implementation Method 1
the reflective layer has two first reflective regions and a second reflective region
Implementation Method 2
phosphor has been excited by the laser light source, and thereby the pure color light source required by the projector is generated
Data Source
AI summary
A wavelength conversion module including a substrate, a reflective layer and a wavelength conversion layer is provided. The reflective layer is located on the substrate, wherein the reflective layer has two first reflective regions and a second reflective region. The second reflective region is located between the two first reflective regions in a radial direction, and the distance from the top of the reflective layer in the second reflective region to the substrate is smaller than the distance from the top of the reflective layer in each of the first reflective regions to the substrate. The wavelength conversion layer is located on the substrate, wherein the reflective layer is located between the substrate and the wavelength conversion layer. In addition, an illumination system, a projection apparatus, and a method of forming a wavelength conversion module are also proposed.