White Light Source With In-Coupling And Homogenizing Elements

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Solution Overview

Problem

Conventional white light sources face challenges in achieving high light power efficiency and luminance uniformity while maintaining a high hiding factor, which is essential for aesthetic integration in lighting applications, as they often require complex designs and increased costs due to high LED densities and complex heat management.

Innovation Solution

A white light source is designed with an array of light emitting elements and an optical waveguide that includes light in-coupling and homogenizing elements, where the light in-coupling elements are arranged on one surface and light homogenizing elements on the opposite surface, allowing for efficient distribution and mixing of light to achieve a homogeneous white light beam, with a highly reflecting substrate and a wavelength up-conversion layer for enhanced performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If high LED density is used to achieve high light power efficiency and luminance uniformity, then the light output quality improves, but the device complexity and cost increase due to complex heat management and integration requirements

Engineering Contradiction:
Improveluminance uniformityVSAvoidheat management complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The invention segments the light management function by introducing a separate light guide component that receives light from multiple LEDs and redistributes it. This allows the LEDs to be spaced farther apart, reducing heat management complexity while maintaining luminance uniformity through the light guide's optical redistribution mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The light guide acts as an intermediary component between the LED array and the final illumination surface. It receives divergent light from individual LEDs and transforms it into a uniform distributed light field, thereby achieving high luminance uniformity without requiring high LED density or complex heat management systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional light mixing arrangements are used to increase the hiding factor, then the aesthetic appearance improves, but the light emitting efficiency decreases

Engineering Contradiction:
Improveaesthetic integrationVSAvoidlight emission efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The invention replaces conventional mechanical light mixing arrangements with an optical waveguide-based light guide. The light guide uses total internal reflection and optical redistribution mechanisms to achieve uniform light distribution and hide individual LED sources, eliminating the need for inefficient mechanical mixing components while maintaining high light emission efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Length of moving object

If the thickness of white light systems is reduced to improve integration, then the device compactness improves, but the ability to collect sufficient light and achieve acceptable in-coupling efficiency decreases

Engineering Contradiction:
Improvesystem thicknessVSAvoidin-coupling efficiency
Core Design Contradiction:
Length of moving objectVSUse of energy by moving object

Solution Approach 1:

The invention changes the optical parameters of the light guide, specifically its refractive index, to enhance light collection and in-coupling efficiency in a thin profile. By optimizing the refractive index matching between the LED封装 material and the light guide, the system achieves acceptable in-coupling efficiency while maintaining reduced thickness for better integration.

Inventive Principle:
Principle #35Parameter changes

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 achieves high light power efficiency and luminance uniformity, effectively hiding individual light emitting elements and providing a uniform white light beam, thus addressing the limitations of prior art while reducing complexity and cost.

Implementation Method 1

an optical waveguide facing the light emitting elements, said optical waveguide comprising a first surface and a second surface facing said first surface, light in-coupling elements being arranged on said first surface and light homogenizing elements being arranged on said second surface

Methodology Applied
Scientific EffectLight propagation in optical waveguide: Waveguide (optics)

Implementation Method 2

Said light homogenizing elements comprise light redirecting and out-coupling elements which allow to distribute the in-coupled light provided by the light in-coupling elements along the length of the waveguide

Methodology Applied
Scientific EffectLight redirection: Refraction

Implementation Method 3

with a highly reflecting substrate

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 4

and a wavelength up-conversion layer for enhanced performance

Methodology Applied
Scientific EffectWavelength up-conversion: Photoluminescence

Data Source

PatentEP3256776B1White light source
Publication Date: 2019.06.12 CSEM CENTRE SUISSE D ELECTRONIQUE ET DE MICROTECHNIQUE SA
  • EP3256776B1 patent drawingFigure 1a
  • EP3256776B1 patent drawingFigure 1b
  • EP3256776B1 patent drawingFigure 1c~2

AI summary

A white light source comprises an array of light emitting elements that are arranged to a light guide comprising at least a first surface and a second surface facing said first surface. The light emitting elements are arranged on a substrate comprising at least one electrical conducting wire connected to said light emitting elements At least a light in-coupling array is arranged on said first surface and, each of said light emitting elements faces a light in-coupling elements The light incoupling elements are arranged to incouple in said light guide a portion of the divergent light beams and are arranged so that the in-coupled angle of at least a part of the light rays of said in-coupled light beam is higher than 45°; At least an array of light homogenizing elements is arranged on said second surface and each of said light homogenizing elements faces a light incoupling element. The tight homogenizing elements are non-uniform structures comprising each at least a light homogenizing portion and at least a light outcoupling portion. The light homogenizing elements are arranged so that the deflection angle of at least a fraction of the incident part of the in-coupled light beam incident on each of said homogenizing elements is higher than 45°. The white light source provides at least a uniform outcoupled white light beam emitted to at least the side of said light guide opposite to said first surface.