Wavelength Converter With Intermediate Refractive Index Matching Layer

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Solution Overview

Problem

Existing wavelength converters face limitations in light use efficiency due to interface reflection caused by refractive index differences between filler layers and ceramic light conversion materials, which deteriorate the flatness of the surface and hinder efficient light conversion.

Innovation Solution

A wavelength converter design featuring a wavelength conversion layer with recesses, a first matching layer with an intermediate refractive index between the wavelength conversion layer and a first flat layer, and a second matching layer with a similar refractive index between the wavelength conversion layer and a second flat layer, reducing interface reflection and enhancing light use efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a filler layer is provided on the surface of the ceramic light conversion material to fill the void and flatten the surface, then the surface flatness is improved, but interface reflection due to light refractive index difference occurs and light loss occurs

Engineering Contradiction:

Improvesurface flatnessVSAvoidlight loss

Core Design Contradiction:

ShapeVSLoss of energy

Solution Approach 1:

A matching layer with intermediate refractive index is introduced between the ceramic light conversion material and the filler layer. This intermediary layer has a refractive index that is an average of the two adjacent layers, serving as a transition medium to reduce the refractive index difference and minimize interface reflection while maintaining surface flatness.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The refractive index parameter of the matching layer is specifically designed to be an average of the ceramic light conversion material and the filler layer. By changing this optical parameter, the system achieves reduced interface reflection and minimized light loss while preserving the surface flatness benefit.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If the void is exposed to the surface of the ceramic light conversion material, then the light use efficiency is maintained, but the flatness of the surface is lost and reflection layers cannot be formed flat

Engineering Contradiction:

Improvelight use efficiencyVSAvoidsurface flatness

Core Design Contradiction:

Loss of energyVSShape

Solution Approach 1:

The matching layer acts as an intermediary that allows the filler layer to fill the voids and flatten the surface while minimizing optical loss. This mediator enables the system to achieve both surface flatness and high light use efficiency by reducing the harmful interface reflection.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention converts the potentially harmful interface reflection into a beneficial configuration by introducing the matching layer. The matching layer transforms the optical interface from a reflective boundary into a gradual transition zone, allowing the filler layer to perform its surface-flattening function without causing significant light loss.

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

The design effectively suppresses interface reflection and improves light use efficiency by minimizing refractive index differences, allowing for efficient conversion and emission of light, as demonstrated by the high reflectance of the dichroic layer for fluorescent light and low reflectance for excitation light.

Implementation Method 1

a light refractive index of the first layer is an intermediate light refractive index between a light refractive index of the wavelength conversion layer and a light refractive index of the first flat layer

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

interface reflection due to a light refractive index difference between the filler layer and the ceramic light conversion material occurs and a light loss occurs

Methodology Applied

Scientific EffectInterface reflection: Reflection

Implementation Method 3

a wavelength conversion layer including a recess on a surface thereof and configured to convert first light having a first wavelength into second light having a second wavelength different from the first wavelength

Methodology Applied

Scientific EffectWavelength conversion: Fluorescence

Data Source

PatentUS20240168366A1Wavelength converter, light source device, and projector

Publication Date: 2024.05.23 SEIKO EPSON CORP

AI summary

A wavelength converter includes a wavelength conversion layer including a first recess on a first surface thereof and configured to convert blue excitation light into yellow fluorescent light, a first matching layer provided on the light incident surface of the wavelength conversion layer, and a first flat layer provided on a second surface on the opposite side of a surface of the first matching layer facing the wavelength conversion layer, the first flat layer entering the first recess of the light incident surface. A light refractive index of the first matching layer is an intermediate light refractive index between a light refractive index of the wavelength conversion layer and a light refractive index of the first flat layer.