Ring-Shaped Phosphor Illumination for Thermal Load Reduction

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Solution Overview

Problem

Existing solid-state lighting apparatuses face challenges in achieving high output while minimizing thermal load on the phosphor layer, as dispersion of light leads to loss and increased temperature, affecting wavelength conversion efficiency.

Innovation Solution

A wavelength conversion device is introduced, featuring a diffractive microlens array that projects light from the solid-state light source onto the phosphor layer in a ring shape, dispersing energy and reducing concentration, thereby minimizing thermal load and maintaining high output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If light from solid-state light source is directly irradiated onto phosphor layer, then wavelength conversion efficiency is maintained, but thermal load on phosphor layer increases causing temperature rise and efficiency deterioration

Engineering Contradiction:
Improvewavelength conversion efficiencyVSAvoidphosphor layer temperature
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The invention divides the phosphor layer into multiple sections (first phosphor layer and second phosphor layer) with different phosphor materials having different excitation wavelengths. The blue light from the solid-state light source is split into multiple wavelength bands, with each band irradiating a different phosphor section. This segmentation distributes the thermal load across multiple phosphor materials instead of concentrating it on a single phosphor layer, thereby reducing the temperature rise while maintaining overall wavelength conversion efficiency.

Inventive Principle:
Principle #1Segmentation

2Temperature

If diffusion means is used to diffuse light from solid-state light source, then thermal load on phosphor layer is reduced, but light dispersion loss increases making high output difficult

Engineering Contradiction:
Improvephosphor layer temperatureVSAvoidlight dispersion loss
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The invention applies local quality by using a light separating means with different optical characteristics for different spatial regions. The light separating means includes a first region that separates blue light into specific wavelength bands and a second region with different separation characteristics. This allows different portions of the light to be directed to appropriate phosphor sections with matching excitation characteristics, reducing unnecessary light dispersion loss while still distributing thermal load effectively across the phosphor layers.

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

The solution effectively suppresses temperature rise in the phosphor layer, allowing for increased light emission without loss, achieving high output while reducing thermal stress and maintaining efficient wavelength conversion.

Implementation Method 1

an optical component that projects light emitted by the light source onto an incidence face of the phosphor layer in a ring shape by diffraction

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

a phosphor layer that converts a wavelength of light from the light source incident on an incidence face

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3425268B1Wavelength conversion device and illuminating device
Publication Date: 2020.01.01 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3425268B1 patent drawingFigure 1
  • EP3425268B1 patent drawingFigure 2
  • EP3425268B1 patent drawingFigure 3A

AI summary

A wavelength conversion device (1) includes: a light source (11) that emits light having a predetermined wavelength included in a wavelength range from ultraviolet light to visible light; a phosphor layer (13) that converts the wavelength of light from the light source (11) which is incident on an incidence face thereof; and an optical component (21) that is disposed between the light source (11) and the phosphor layer (13), and projects light emitted by the light source (11) onto the incidence face of the phosphor layer (13) in a ring shape.