Phosphor Wheel Airflow Circulation for Projector Cooling

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Solution Overview

Problem

The existing phosphor wheel devices suffer from low cooling efficiency due to airflow stagnation in the corrugated plate shape of the heat exchange portion, leading to inefficient heat dissipation.

Innovation Solution

A phosphor unit with a peripheral wall and heat receiving fins that redirect airflow to enhance circulation and improve heat dissipation, combined with a thermoelectric conversion element for further heat management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the plate member is formed in the corrugated plate shape to increase heat exchange area, then heat exchange efficiency is improved, but airflow circulation becomes stagnant and cooling efficiency decreases

Engineering Contradiction:

Improveheat exchange efficiencyVSAvoidcooling efficiency

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The plate member is divided into multiple recesses (first recesses and second recesses) with different structures. The first recesses have inclined surfaces that guide airflow, while the second recesses have curved surfaces for different heat exchange functions. This segmentation allows simultaneous optimization of heat exchange area and airflow circulation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a conventional corrugated plate shape, the patent inverts the design by creating recesses that actively guide airflow in a specific circulation pattern. The inclined surfaces of the recesses redirect airflow to prevent stagnation, transforming the plate from a passive heat exchange surface to an active airflow management component.

Inventive Principle:

Principle #13The other way round (Inversion)

2Illumination intensity

If the phosphor wheel rotates at high speed to improve light output, then luminance increases, but heat generation increases and cooling becomes less effective

Engineering Contradiction:

ImproveluminanceVSAvoidheat generation

Core Design Contradiction:

Illumination intensityVSTemperature

Solution Approach 1:

The plate member with its specially designed recesses acts as an intermediary between the phosphor wheel and the cooling system. It captures heat from the rotating phosphor wheel and redirects it through controlled airflow paths, enabling effective heat removal even at high rotation speeds where direct cooling becomes less effective.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the housing is sealed to protect internal components, then reliability improves, but heat dissipation becomes less efficient

Engineering Contradiction:

Improvecomponent protectionVSAvoidheat dissipation

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The cooling system is designed to be self-sufficient within the sealed housing. The rotating phosphor wheel itself generates the airflow needed for cooling, and the plate member's recesses guide this airflow to create an internal circulation system that does not require external openings, thus maintaining both sealing and heat dissipation.

Inventive Principle:

Principle #25Self-service

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 redesigned airflow circulation and heat dissipation system significantly enhances the cooling efficiency of the phosphor wheel, ensuring effective temperature regulation and prolonged device performance.

Implementation Method 1

a phosphor wheel that converts excitation light into fluorescent light

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 2

a part of heat of the phosphor wheel is conducted to the heat exchange portion

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

Air heated by the phosphor wheel hits an inner surface of the heat exchange portion

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 4

a rotating fin that generates an airflow inside the housing

Methodology Applied

Scientific EffectForced convection: Forced Convection

Implementation Method 5

a thermoelectric conversion element provided between the heat receiving plate and the heat dissipating device

Methodology Applied

Scientific EffectSeebeck effect: Seebeck Effect

Data Source

PatentEP4400910B1Phosphor unit, light source device, and projector

Publication Date: 2026.03.18 SEIKO EPSON CORP

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AI summary

A phosphor unit includes:a phosphor wheel; a peripheral wall surrounding the phosphor wheel along a circumferential direction around the rotation axis; a heat receiving plate intersecting the rotation axis, facing the phosphor wheel, and spaced apart from the phosphor wheel; and a heat receiving fin fixed to the heat receiving plate and surrounded by the peripheral wall. The phosphor wheel includes a substrate having a first surface and a second surface facing the heat receiving plate, and configured to rotate around the rotation axis, a wavelength conversion portion disposed on the first surface, and a heat dissipating fin disposed on the second surface, and including a plurality of first fins that generate an airflow in a direction from a center of the second surface toward outside by rotation of the substrate and dissipate heat transferred from the wavelength conversion portion to the airflow. The heat receiving fin includes a plurality of second fins through which an airflow circulating from the phosphor wheel to the phosphor wheel via the peripheral wall and the heat receiving plate flows, and that receives heat from the flowing airflow and transfers the heat to the heat receiving plate.