Wavelength Conversion Device Cooling via Phase Transition
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Solution Overview
Problem
Existing wavelength conversion devices face challenges in improving cooling efficiency for phosphors, leading to reduced illumination efficiency and white balance maintenance in projectors, as increased light density on phosphors can overwhelm cooling mechanisms, and larger designs are required to enhance cooling, which is inefficient.
Innovation Solution
A wavelength conversion device with a rotating substrate and a first cooling device encapsulating working fluid, featuring an evaporator and condenser, where the liquid retaining part is positioned at the outer edge to efficiently transfer heat from the wavelength conversion element, utilizing centrifugal force to enhance fluid movement and cooling efficiency without increasing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the density of light irradiated on the phosphor is increased to improve illumination efficiency, then the brightness of the projected image is improved, but the cooling efficiency for the phosphor deteriorates
Solution Approach 1:
The patent employs phase transition of working fluid (liquid to gas to liquid) within the cooling device to achieve efficient heat removal. The working fluid evaporates when receiving heat from the phosphor, then condenses back to liquid, creating a continuous cooling cycle that can handle high heat loads without increasing device size
Solution Approach 2:
The patent uses a liquid-gas phase change system (thermal siphon effect) to transport heat away from the phosphor. The working fluid circulates through evaporation and condensation processes, creating an efficient passive cooling mechanism that addresses the heat generation problem caused by high light density
2Temperature
If the diameter of the ring-shaped phosphor or rotating body is increased to improve cooling efficiency, then the cooling efficiency is improved, but the device size is increased
Solution Approach 1:
The patent uses phase transition of working fluid to achieve high cooling efficiency in a compact form. The evaporation and condensation process creates efficient heat transfer without requiring large thermal mass or extended cooling surfaces, thus maintaining small device size while achieving superior cooling performance
Solution Approach 2:
The patent changes the thermal state parameters of the working fluid (temperature, pressure, phase) to optimize cooling efficiency. By controlling the phase transition conditions, the system achieves high heat transfer coefficients in a compact configuration, avoiding the need to increase device dimensions
3Productivity
If the phosphor is not sufficiently cooled, then the illumination efficiency is reduced, but increasing cooling mechanism complexity is avoided
Solution Approach 1:
The cooling device operates autonomously using the thermal siphon effect, where heat from the phosphor automatically drives the phase transition and circulation of working fluid. This self-regulating mechanism maintains optimal phosphor temperature without requiring external control systems, sensors, or complex active cooling components, thus preserving illumination efficiency while minimizing complexity
Solution Approach 2:
The patent uses passive phase transition-based cooling (thermal siphon) that automatically responds to heat load changes. The working fluid naturally evaporates and condenses based on temperature gradients, providing adaptive cooling that maintains illumination efficiency without complex control mechanisms
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
The solution effectively improves cooling efficiency for the wavelength conversion element, stabilizes illumination efficiency, and maintains white balance by efficiently transferring heat through the evaporation and condensation of working fluid, reducing the risk of overheating and noise, while maintaining a compact device size.
Implementation Method 1
an evaporator provided in the space and configured to evaporate the working fluid in a liquid phase with heat transferred from the wavelength conversion element to change the working fluid in the liquid phase to the working fluid in a gas phase
Implementation Method 2
a condenser provided in the space and configured to condense the working fluid in the gas phase to change the working fluid in the gas phase to the working fluid in the liquid phase
Implementation Method 3
utilizing centrifugal force to enhance fluid movement and cooling efficiency without increasing device size
Data Source
AI summary
A wavelength conversion device includes a rotating device, a substrate rotated by the rotating device, a wavelength conversion element, and a first cooling device including, on an inside, a space in which working fluid is encapsulated, the first cooling device cooling the wavelength conversion element. The first cooling device is disposed in a position corresponding to the wavelength conversion element. The space extends from an outer edge side of the substrate to a rotation axis side. The first cooling device includes an evaporator and a condenser which are provided in the space. The evaporator includes a liquid retaining part configured to retain the working fluid in a liquid phase. The liquid retaining part is provided at the outer edge side in the space and disposed in the position corresponding to the wavelength conversion element.