Optical Waveguide Circular Deflection Structures

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Solution Overview

Problem

Existing light guides used for backlighting decorative elements appear unaesthetic when unilluminated due to visible light deflection structures, and they often lack sufficient luminance, making them unsuitable for translucent, flat decorative elements.

Innovation Solution

A light guide design featuring light deflection structures with cross sections in a circular or circumferential shape on the visible surface, where the diameter of these structures is between 0 micrometers and 50 micrometers, and their centers are spaced such that the distance between them is greater than the diameter divided by 0.33, ensuring they are barely visible in the unilluminated state while maintaining sufficient luminance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light deflection structures are made larger to improve light coupling efficiency and luminance, then luminance is improved, but visibility of the structures in the unilluminated state increases making them more aesthetic

Engineering Contradiction:
ImproveluminanceVSAvoidvisibility of light deflection structures
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by precisely controlling the diameter of light deflection structures to be between 0.001 mm and 50 µm, and spacing them at distances greater than d/0.33. This parameter optimization allows the structures to remain invisible to the human eye in the unilluminated state while still effectively deflecting light to provide sufficient luminance when illuminated.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If light deflection structures are made smaller to improve aesthetics in the unilluminated state, then visibility is reduced, but luminance on the visible side decreases

Engineering Contradiction:
Improvevisibility of light deflection structuresVSAvoidluminance
Core Design Contradiction:
Object-affected harmful factorsVSIllumination intensity

Solution Approach 1:

The patent determines optimal parameter ranges through systematic analysis: diameter d between 0.001 mm and 50 µm, and spacing A > d/0.33. These parameter changes ensure that even at the upper limit of visibility, the structures remain barely visible while maintaining sufficient light deflection capability for adequate luminance output.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a dense arrangement of light deflection structures with spacing A > d/0.33, which creates a partial overlap in their light deflection zones. This excessive density ensures that sufficient luminance is achieved across the entire visible surface, compensating for the small individual size of each structure.

Inventive Principle:
Principle #16Partial or excessive action

3Illumination intensity

If the distance between light deflection structures is reduced to increase their density, then luminance is improved, but the structures become more visible in the unilluminated state

Engineering Contradiction:
ImproveluminanceVSAvoidvisibility of light deflection structures
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent establishes the critical spacing parameter A > d/0.33, which creates an optimal balance point. At this spacing, the structures are dense enough to provide uniform luminance coverage but sparse enough to remain invisible when unilluminated. This parameter relationship directly resolves the contradiction between density and visibility.

Inventive Principle:
Principle #35Parameter changes

4Illumination intensity

If the diameter of light deflection structures is increased to improve light deflection efficiency, then luminance is improved, but manufacturing precision requirements increase

Engineering Contradiction:
ImproveluminanceVSAvoiddimensional accuracy of light deflection structures
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The patent specifies a diameter range of 0.001 mm to 50 µm that balances multiple factors: large enough to provide effective light deflection, small enough to remain invisible, and within achievable tolerances for manufacturing processes. This parameter selection resolves the contradiction between efficiency and manufacturability.

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

The design ensures that light deflection structures are hardly visible in the unilluminated state and provide sufficient luminance on the visible side, making the light guide aesthetically pleasing and functional when illuminated.

Implementation Method 1

Light from a lamp is coupled into the light guide via the light coupling surface. The coupled light propagates in the light guide and is redirected by means of the light deflection structures

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2853806B1Optical waveguide
Publication Date: 2020.11.25 WEIDPLAS
  • EP2853806B1 patent drawingFigure 1
  • EP2853806B1 patent drawingFigure 2
  • EP2853806B1 patent drawingFigure 3

AI summary

A light guide (1, 1', 1'', 1''', 1''', 1''' '', 1''' '', 1'''' '''', 1'''' '''', 1'''' '''', 1'''' '''', 1""' ""') is provided comprising at least two light deflection structures (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13) which have a cross-section arranged in a surface (19), wherein the cross-section of each light deflection structure in the surface (19) is a circle (K, K2, K3, K4, K5, K6, K7, K8, K9, K10, K11, K12, K13) or around the cross-section (Q, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q10, Q11, Q12, Q13) of a respective light deflection structure in the area (19) a circumcircle (U, U2, U3, U4, U5, U6, U7, U8, U9, U10, U11, U12, U13) can be defined, wherein light coupled into the light guide via a light coupling surface (14) can be coupled out of the light guide via a viewing surface (18) and the at least two light deflection structures. The diameter d (d2, d3, d4, d5, d6, d7, d8, d9, d10, d11, d12, d13) of the circle orof the circumcircle in the area (19) lies in the range from greater than 0 micrometers to 50 micrometers, wherein the center point (M2, M3, M4, M5, M6, M7, M8, M9, M10, M11, M12, M13) of the circle or circumcircle in the area (19) of a respective light deflection structure (2) to the center point (M3, M4, M5, M6, M7, M8, M9, M10, M11, M12, M13) of the circle or circumcircle in the area (19) of all other light deflection structures (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13) is a distance A (A23, A24, A25, A26, A27, A28, A29, A210, A211, A212, A213) exhibits, wherein the distance A is greater than the diameter d (d2) of the circle or circumcircle in the area (19) of the respective light deflection structure (2) divided by the value 0.33.