Phosphor Wheel Radial Segmentation for Thermal Management
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Solution Overview
Problem
Existing projectors face a decrease in excitation efficiency of fluorescent elements due to thermal decay, leading to reduced luminous efficiency over time, particularly in one-chip and three-chip DLP projectors.
Innovation Solution
An optical device featuring a phosphor wheel with two non-overlapping phosphor regions at different radial positions, each with multiple color sections, where two light sources emit separate light spots that align with color sections having the same fluorescent characteristics during rotation, reducing heat accumulation and enhancing excitation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single phosphor region is used with one light source, then the structure is simple, but thermal decay reduces excitation efficiency over time
Solution Approach 1:
The phosphor wheel is divided into two separate phosphor regions (first phosphor region and second phosphor region) positioned at different radial locations. Each region has its own light source (first light source and second light source), allowing independent excitation and reducing thermal accumulation at any single location, thereby maintaining excitation efficiency over time.
Solution Approach 2:
The patent transitions from a single-point excitation model to a distributed radial excitation model. By positioning phosphor regions at different radial distances from the center of the phosphor wheel, the system distributes thermal load across multiple spatial dimensions, preventing localized thermal decay while maintaining overall system simplicity.
2Illumination intensity
If high power light sources are used to maintain brightness, then luminous output is high, but thermal decay effect increases
Solution Approach 1:
The total luminous output requirement is segmented across two light sources positioned at different radial locations. Each light source operates at lower power individually, reducing heat accumulation, while their combined output maintains the required brightness level. The phosphor regions are excited separately, distributing thermal load spatially.
Solution Approach 2:
The phosphor wheel acts as an intermediary that converts distributed optical excitation from multiple light sources into unified colored light output. By using phosphor conversion at multiple radial positions, the system achieves high brightness output while distributing thermal generation across multiple lower-power excitation points rather than one high-power point.
3Reliability
If multiple phosphor regions are used to reduce thermal decay, then excitation efficiency improves, but device complexity increases
Solution Approach 1:
The optical system is segmented into two independent excitation channels (first light source + first phosphor region, second light source + second phosphor region), each operating autonomously. This segmentation improves luminous efficiency by reducing thermal decay, while the modular structure allows for manageable complexity through standardized component repetition.
Solution Approach 2:
The patent implements a universal excitation-phosphor conversion module that can be replicated at different radial positions. Each module consists of a light source and its corresponding phosphor region, following the same operational principles. This multi-functionality approach allows the system to handle multiple excitation zones with consistent design patterns, reducing overall system complexity despite increased functionality.
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 improves brightness and color saturation of corresponding colors, reduces thermal decay effects, and allows for adjustable color proportion and saturation by controlling light output powers and central angles of color sections.
Implementation Method 1
The phosphor regions are located at different radial positions of the phosphor wheel and not overlapped. Each of the phosphor regions has a plurality of color sections. The light sources emit two light beams so as to respectively provide two light spots on the phosphor wheel.
Data Source
AI summary
An optical device includes a phosphor wheel and two light sources. The phosphor wheel has two phosphor regions. The phosphor regions are located at different radial positions of the phosphor wheel and are not overlapped. Each of the phosphor regions has a plurality of color sections. The light sources emit two light beams so as to respectively provide two light spots on the phosphor wheel. During the rotation of the phosphor wheel, the light spots are located at the color sections having the same fluorescent characteristic respectively in the phosphor regions.