Concentric Phosphor Wheel for Laser Projector Thermal Management
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Solution Overview
Problem
Conventional phosphor wheels in laser projectors suffer from low red light efficiency due to thermal decay and limited lumen output, which affects the overall white light lumen efficiency and color balance.
Innovation Solution
A phosphor wheel design featuring concentric red and yellow phosphor regions on a substrate, where the red phosphor region surrounds the yellow phosphor region, is excited by a blue laser to produce a white light that is split and modulated to achieve improved red, blue, and green light combinations, enhancing the final white light brightness and color coordination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high excitation laser watt is used to improve white light lumen output, then total lumen of the projector is enhanced, but red phosphor efficiency is degraded due to thermal decay
Solution Approach 1:
The phosphor wheel is divided into multiple distinct phosphor regions (red, green, blue, yellow) arranged in specific patterns. This segmentation allows each region to be optimized for its specific function and reduces thermal interference between different phosphor materials, maintaining red phosphor efficiency while achieving high total lumen output through coordinated excitation of all regions.
Solution Approach 2:
Different phosphor materials with specific properties are placed in different regions of the wheel. The red phosphor region is strategically positioned and designed with specific characteristics to optimize its performance under blue laser excitation, while other regions contain phosphors optimized for their respective wavelength ranges, creating local quality variations that resolve the efficiency-degradation problem.
2Stability of the object's composition
If red phosphor is used to generate red light, then the projector can achieve white balance, but red light efficiency is inherently low and shifts the D65 white balance
Solution Approach 1:
A yellow phosphor region is introduced as an intermediary element in the phosphor wheel configuration. The yellow phosphor, when excited by the blue laser, generates yellow light that can be optically processed (split into green and red components) to supplement the red light output. This intermediary approach provides an additional pathway to generate red light with higher efficiency, compensating for the inherent low efficiency of direct red phosphor excitation while maintaining accurate white balance.
3Adaptability or versatility
If a single yellow phosphor region is used with a splitter to generate red and green light, then the system can produce RGB light beams, but red light efficiency remains low (about 12 lm/W) and limits white light lumen efficiency
Solution Approach 1:
Instead of using a single yellow phosphor region, the invention segments the phosphor wheel into multiple dedicated regions including a specific red phosphor region, green phosphor region, blue phosphor region, and yellow phosphor region. This segmentation allows direct generation of red, green, and blue light through targeted phosphor excitation, eliminating the need for inefficient optical splitting of yellow light and significantly improving overall white light lumen efficiency while maintaining RGB light beam generation capability.
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 design significantly increases the final white light brightness and effective ratio, overcoming the limitations of low red light efficiency and thermal decay, while maintaining optimal color temperature and balance.
Implementation Method 1
a blue laser source for applying a blue laser to the interface between the second phosphor region and the first phosphor region, thereby simultaneously exciting the second phosphor region and the first phosphor region to form a first white light
Data Source
AI summary
Disclosed is a phosphor wheel including a substrate, a first phosphor region on the substrate, and a second phosphor region on the substrate. The first phosphor region and the second phosphor region are concentric patterns without any space between their interface. Moreover, the second phosphor region is set to surround the first phosphor region.