Wavelength Converter Light Source Apparatus for Projectors

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Solution Overview

Problem

In projector light source apparatuses using fluorescence, stray light from unconverted excitation light leads to reduced illumination efficiency and increased heat generation, necessitating larger and more complex cooling systems to compensate for the loss.

Innovation Solution

A light source apparatus with a wavelength converter and a second optical element that redirects reflected excitation light back to the wavelength converter, enhancing the conversion efficiency and reducing the need for increased light source output, thereby simplifying heat dissipation and minimizing apparatus size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the amount of light outputted by the light source is increased to compensate for stray light loss, then the illumination efficiency is improved, but the amount of heat generated by the light source increases

Engineering Contradiction:

Improveillumination efficiencyVSAvoidheat generation

Core Design Contradiction:

Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent converts the harmful stray light that would normally be lost into a beneficial resource by redirecting it back to the wavelength converter. The reflection layer reflects unconverted excitation light back toward the wavelength converter, and the diffuser diffuses this reflected light to increase the overall amount of fluorescence generated, thereby improving illumination efficiency without increasing heat generation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Temperature

If the performance of cooling the light source is improved to handle increased heat, then the heat dissipation capability is enhanced, but the size of the light source apparatus increases

Engineering Contradiction:

Improveheat dissipation capabilityVSAvoidapparatus size

Core Design Contradiction:

TemperatureVSVolume of stationary object

Solution Approach 1:

Instead of simply dissipating heat through larger cooling systems, the patent converts the harmful stray light into useful fluorescence by redirecting it to the wavelength converter. This approach improves heat dissipation capability indirectly by reducing the total light output needed, thereby maintaining compact apparatus size.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Illumination intensity

If the amount of light outputted by the light source is increased to compensate for stray light, then the illumination intensity is improved, but the apparatus complexity increases due to larger cooling systems

Engineering Contradiction:

Improveillumination intensityVSAvoidcooling system complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The patent improves illumination intensity by converting stray light into additional fluorescence through the reflection layer and diffuser combination. This eliminates the need for complex cooling systems, thereby maintaining simple apparatus structure while achieving high illumination intensity.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 increases the amount of fluorescence generated without increasing the light source's output power, resulting in high-power illumination with a reduced apparatus size and improved efficiency.

Implementation Method 1

a wavelength conversion layer that is provided on a light incident side of the reflection layer and converts the excitation light in terms of wavelength into wavelength converted light having a wavelength band different from a wavelength band of the excitation light

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 2

a second optical element that is disposed in an optical path between the light source and the wavelength converter and causes at least part of reflected light of the excitation light reflected off the wavelength converter to exit toward the wavelength converter

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS11762268B2Light source apparatus and projector

Publication Date: 2023.09.19 SEIKO EPSON CORP

AI summary

A light source apparatus according to an aspect of the present disclosure includes a light source that outputs excitation light, a wavelength converter including a reflection layer and a wavelength conversion layer that is provided on the light incident side of the reflection layer and converts the excitation light in terms of wavelength into wavelength converted light having a wavelength band different from that of the excitation light, a first optical element that causes the excitation light from the light source to be incident on the wavelength converter, and a second optical element that is disposed in the optical path between the light source and the wavelength converter and causes at least part of reflected light of the excitation light reflected off the wavelength converter to exit toward the wavelength converter.