Internal Light Deflection Structures in Optical Waveguides

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Solution Overview

Problem

Light guides used in various applications, such as automobile construction and room illumination, face challenges in maintaining efficient and adjustable light extraction while being insensitive to surface damage, which can alter their radiation characteristics.

Innovation Solution

A light guide with numerous light deflection structures arranged internally, featuring elongated rod-shaped bases and optional flags, produced by local melting of the material using lasers, allowing for targeted and adjustable light deflection without surface damage, and enabling uniform or focused light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If light deflection structures are arranged on the outer surface of the light guide, then light extraction efficiency is improved, but the light guide becomes sensitive to surface damage which alters radiation characteristics

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidinsensitivity to surface damage
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent inverts the conventional arrangement by placing light deflection structures inside the light guide rather than on the outer surface. This internal arrangement maintains light extraction efficiency while protecting the deflection structures from surface damage, thereby resolving the contradiction between productivity and reliability.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent transitions the light deflection structures from a two-dimensional surface arrangement to a three-dimensional internal arrangement within the light guide volume. This dimensional change allows the structures to function effectively while being shielded from external damage, addressing both light extraction efficiency and damage resistance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If a large number of light deflection structures are provided to achieve uniform illumination, then light extraction is improved, but the device complexity increases

Engineering Contradiction:
Improveuniformity of illuminationVSAvoidnumber of light deflection structures
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent changes the geometric parameters of the light deflection structures, specifically making them elongated with a high aspect ratio (length much larger than width). This parameter change allows fewer structures to achieve the same light extraction efficiency, reducing device complexity while maintaining uniform illumination.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating light deflection structures with specific elongated geometries at specific locations inside the light guide. This targeted approach with optimized local structures achieves uniform illumination more efficiently than a dense uniform arrangement, reducing overall device complexity.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If light deflection structures are created using laser processing, then manufacturing precision is improved, but the production process becomes more complex

Engineering Contradiction:
Improveprecision of light deflection structuresVSAvoidsimplicity of production process
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces conventional mechanical machining methods with laser processing to create light deflection structures. This substitution enables precise control of the elongated structure geometry and internal positioning while maintaining ease of manufacture through a contactless, automated process.

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

Solution Approach 2:

The patent utilizes the phase transition of material during laser processing to create the light deflection structures. The laser induces localized melting and resolidification, enabling precise formation of the elongated internal structures with controlled geometry, achieving high manufacturing precision through thermal phase changes.

Inventive Principle:
Principle #36Phase transitions

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 internal light deflection structures ensure efficient and adjustable light extraction, maintaining radiation characteristics even with surface damage, and allow for various light effects and designs, including decorative elements and uniform illumination.

Implementation Method 1

The light deflection structures are created using laser processing by locally melting the polymer material of the light guide

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

locally melting the polymer material of the light guide

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

light rays which strike one of the light deflection structures, in particular laterally, that is from a direction essentially perpendicular to the longitudinal direction of the light deflection structures, experience a deflection towards the longitudinal direction of the light deflection structure

Methodology Applied
Scientific EffectLight deflection: Refraction

Data Source

PatentEP3440403B1Light guide with light deflection structures
Publication Date: 2021.03.31 WEIDPLAS
  • EP3440403B1 patent drawingFigure 1
  • EP3440403B1 patent drawingFigure 2
  • EP3440403B1 patent drawingFigure 3

AI summary

The invention relates to an optical waveguide (1), which has a plurality of light-deflecting structures (3), which are arranged within the optical waveguide (1). Each light-deflecting structure (3) has an elongated main body (4), which is dimensioned larger in the longitudinal direction of the main body than in the directions perpendicular to said longitudinal direction by a multiple.