Concave-Convex Wavelength Converter for Efficient Static Phosphor Emission

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Solution Overview

Problem

Phosphor wheel type wavelength converters require rotary driving devices, complicating the structure and increasing the risk of failure, making it difficult to reduce the size and enhance light emission efficiency.

Innovation Solution

A wavelength converter using a phosphor ceramic with a concave-convex structure and a combination of phosphors that emit fluorescence due to parity-forbidden and parity-allowed transitions, allowing for efficient light extraction without a rotary driving device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a phosphor wheel type wavelength converter is used, then light emission efficiency can be improved, but the structure becomes complicated and the risk of failure increases due to the rotary driving device

Engineering Contradiction:

Improvelight emission efficiencyVSAvoidstructure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the rotary driving device from the wavelength converter system. By using a stationary phosphor wheel without rotation mechanism, the complicated mechanical structure is eliminated while maintaining the wavelength conversion function, thus resolving the contradiction between light emission efficiency and structural complexity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of rotating the phosphor wheel to achieve wavelength conversion, the patent inverts the approach by using a stationary phosphor wheel with specific phosphor arrangements that enable wavelength conversion without rotation, thereby simplifying the structure while maintaining functionality

Inventive Principle:

Principle #13The other way round (Inversion)

2Adaptability or versatility

If a rotary driving device is used to rotate the phosphor wheel, then wavelength conversion can be achieved, but the size of the device increases and durability decreases

Engineering Contradiction:

Improvewavelength conversion capabilityVSAvoiddevice durability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The rotary driving device is completely extracted from the system. The patent achieves wavelength conversion using a stationary phosphor wheel with specifically arranged phosphors, eliminating mechanical moving parts that reduce durability and increase device size

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical rotation system with a stationary optical system. Wavelength conversion is achieved through the optical properties of arranged phosphors rather than mechanical rotation, thereby improving reliability and reducing device size

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If phosphors are arranged in a phosphor wheel, then light emission efficiency can be enhanced, but heat generation causes temperature quenching and reduces efficiency

Engineering Contradiction:

Improvelight emission efficiencyVSAvoidtemperature quenching

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent segments the phosphor arrangement into multiple independent phosphors positioned at different locations on the stationary phosphor wheel. This segmentation allows better heat dissipation and reduces temperature quenching while maintaining overall light emission efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different phosphors are placed at different local positions on the phosphor wheel, each optimized for specific wavelength conversion tasks. This local optimization allows efficient light emission while distributing heat generation across multiple locations, reducing temperature quenching

Inventive Principle:

Principle #3Local quality

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

Enhances light emission efficiency by optimizing the thickness and arrangement of phosphors, suppressing temperature quenching, and improving durability and impact resistance.

Implementation Method 1

a phosphor ceramic (11) containing a first phosphor that emits fluorescence due to a parity-forbidden transition, and a phosphor part (12) containing a second phosphor that emits fluorescence due to a parity-allowed transition

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP4296731B1Wavelength converter and light emitting device provided therewith

Publication Date: 2025.08.13 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

Figure 1(a)~1(b)
Figure 2(a)~2(b)
Figure 3~4

AI summary

Provided is a wavelength converter (10) including a phosphor ceramic (11) containing a first phosphor that emits fluorescence due to a parity-forbidden transition, and a phosphor part (12) containing a second phosphor that emits fluorescence due to a parity-allowed transition. A main surface of the phosphor ceramic (11) has a concave and convex structure including a plurality of convex parts (11b) and a plurality of concave parts (11c). The phosphor part (12) is arranged inside the plurality of concave parts (11c) in the phosphor ceramic (11). Also provided is a light emitting device (100) including the wavelength converter (10), and a solid-state light source (20) that emits light with which the wavelength converter (10) is irradiated and which has a light emission peak within a wavelength range of 400 nm or more and less than 500 nm.