Luminescent Wheel Light Source Unit for Projector Thermal Management
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Solution Overview
Problem
Conventional projectors using high-intensity discharge lamps have low light utilization efficiency and short lamp life, while LED-based solutions face issues with luminescent material heating and uneven luminance, leading to reduced image quality and shortened product life.
Innovation Solution
A light source unit with a luminescent wheel and two separate light source devices emitting different wavelength bands, controlled by a time-sharing system to prevent overheating and synchronize illumination cycles with the wheel's rotation, ensuring the luminescent materials are not continuously heated, thus maintaining stable projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the excitation light source is kept turned on at all times to illuminate the luminescent wheel, then the luminescent materials can continuously emit light, but the luminescent materials are heated which reduces luminous efficiency and produces unevenness in luminance
Solution Approach 1:
The patent applies periodic action by controlling the excitation light source to be turned on and off in cycles, illuminating the luminescent wheel only during specific time periods rather than continuously. This periodic illumination prevents the luminescent materials from overheating while still enabling them to emit light when needed, thereby maintaining luminous efficiency and uniform luminance across the projection surface.
2Duration of action of moving object
If the excitation light source is kept turned on at all times, then continuous light emission is achieved, but the aging deterioration of the excitation light source is promoted and product life is shortened
Solution Approach 1:
The patent implements periodic action by controlling the excitation light source to operate in intermittent cycles rather than continuously. The light source is turned on during illumination periods and turned off during non-illumination periods, which reduces cumulative operating hours and thermal stress on the light source components. This extends the operational lifespan of the excitation light source while still providing continuous light emission capability for the projector system as a whole.
3Illumination intensity
If the luminescent materials are continuously illuminated, then steady light output is maintained, but the luminance and color saturation differ color by color and colors cannot be reproduced accurately
Solution Approach 1:
The patent applies periodic action by sequentially illuminating different colored luminescent materials in the luminescent wheel during different time periods within each cycle. This time-division multiplexing approach allows each luminescent material to be illuminated and emit its characteristic color light during its designated time slot, preventing thermal interference between different colors and enabling accurate color reproduction while maintaining steady overall light output.
Solution Approach 2:
The patent implements dynamics by synchronizing the rotation of the luminescent wheel with the periodic illumination cycles of the excitation light source. The wheel rotates to position different colored luminescent materials in the illumination path at appropriate times, dynamically coordinating the spatial and temporal aspects of multi-color light emission. This dynamic synchronization ensures that each color is emitted at the correct time with accurate saturation and luminance.
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 light utilization efficiency, maintains consistent luminance, and extends the life of the projector by preventing overheating and reducing wear on the luminescent materials, enabling high-quality, long-lasting image projection.
Implementation Method 1
a luminescent wheel in which a luminescent material is laid on at least a whole circumferential area through which the excitation light passes, the luminescent material receiving the light emitted from the excitation light shining device as excitation light to emit a luminescent light ray of a predetermined wavelength band
Data Source
AI summary
To provide a light source unit enabling a stable projection without a luminescent material heating and a projector, a projector of the invention including a light source unit, a display device, a light guiding optical system, a projection side optical system and a light source control device. The light source unit includes an excitation light shining device, a luminescent wheel emitting a luminescent ray of a green wavelength band and a light source optical system collecting rays from the luminescent wheel and respective light sources on a predetermined plane. The light source control device controls the excitation light shining device, each light source device of red and blue so that a period of time required for turning-on once of the excitation light shining device, and each light source device of red and blue becomes a non-integral multiple of a period of time required for one rotation of the luminescent wheel.