Fresnel Lens Optical Coupler for Vehicle Light Homogeneity

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Solution Overview

Problem

Traditional optical couplers for slab lightguides in vehicle lights face challenges due to space limitations and the need for asymmetric designs, leading to suboptimal light coupling, homogeneity, and angular distribution, especially when the LED's light emitting area does not align directly with the lightguide entrance face.

Innovation Solution

The optical coupler features a Fresnel lens-shaped exit face with a focal point at or behind the LED's light emitting area, and a concave or plane entrance face, designed to refract light and ensure homogeneity and angular distribution, allowing for flexible placement and orientation to match the dimensions of the lightguide entrance face, even in constrained spaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If traditional optical couplers are used in space-constrained vehicle light applications, then device compactness is improved, but light coupling efficiency and homogeneity deteriorate

Engineering Contradiction:

Improveoptical coupler sizeVSAvoidlight coupling efficiency

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The optical coupler is divided into functionally distinct zones: a first optical coupler unit with asymmetric design for optimizing light coupling from the LED, and a second optical coupler unit with symmetric design for ensuring homogeneous light distribution to the lightguide. This segmentation allows each zone to be optimized for its specific function while maintaining overall compactness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the optical coupler are assigned different geometric properties and refractive indices to optimize local light manipulation. The asymmetric first unit addresses the LED-coupling region requirements, while the symmetric second unit addresses the lightguide-interface region requirements, with each region's properties tailored to its specific optical function.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If asymmetric optical coupler designs are used to fit space constraints, then adaptability to different LED positions is improved, but light homogeneity and angular distribution deteriorate

Engineering Contradiction:

Improveplacement flexibilityVSAvoidlight homogeneity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first optical coupler unit employs asymmetric geometric design with different curvature radii in different regions, allowing the coupler to adapt to various LED positions and orientations while maintaining effective light coupling. The asymmetric design enables flexible placement without compromising the coupling efficiency.

Inventive Principle:

Principle #4Asymmetry

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 design enhances light homogeneity and angular distribution, reducing light guiding losses and inhomogeneous luminosity, while providing design flexibility for vehicle lighting applications by allowing independent placement of LEDs and lightguides.

Implementation Method 1

The optical coupler entrance and exit faces are configured to refract light emitted by the at least one LED during operation

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

The optical coupler exit face is shaped as a Fresnel lens with a focal point at or behind a light emitting area of the at least one LED

Methodology Applied

Scientific EffectFresnel lens focusing: Fresnel Lens

Data Source

PatentUS12129985B2Optical coupler, design method therefor, and vehicle light therewith

Publication Date: 2024.10.29 LUMILEDS SINGAPORE PTE LTD

AI summary

An optical coupler is described herein. The optical coupler includes at least one optical coupler unit. The at least one optical coupler includes an optical coupler entrance face and an optical coupler exit face. The optical coupler entrance face is configured to face, and receive light emitted by, at least one LED during operation. The optical coupler exit face is shaped as a Fresnel lens with a focal point at or behind a light emitting area of the at least one LED and is configured to face a lightguide entrance face of a slab lightguide. The optical coupler exit face has dimensions that match at least a part of the lightguide entrance face. The optical coupler entrance and exit faces are configured to refract light emitted by the at least one LED during operation.