Optical Waveguide Light Extraction Features

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Solution Overview

Problem

Existing optical waveguides for lighting, particularly those using LEDs, suffer from low efficiency due to losses inherent in coupling light from a Lambertian emitting source into a narrow edge of a waveguide plane, leading to inefficient light distribution and control in applications like roadway and parking lot lighting.

Innovation Solution

The design incorporates a waveguide with a light coupling portion and a light emitting portion, featuring a light transmission portion that optically couples the coupling portion to the emitting portion, and includes light extraction features such as indents, depressions, or facets to control light redirection and extraction, enhancing light distribution and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If light is coupled from a Lambertian emitting source into a narrow edge of a waveguide plane, then light distribution is achieved, but coupling efficiency is low due to inherent losses

Engineering Contradiction:

Improvecoupling efficiencyVSAvoidwaveguide structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent introduces a light redirection feature as an intermediary element between the light source and the waveguide. This redirection feature captures light from the Lambertian emitting source and redirects it into the waveguide at optimized angles, serving as a mediator that improves coupling efficiency without requiring complex waveguide modifications

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the waveguide structure by adding light extraction features (such as prisms, gratings, or textured surfaces) that change the optical parameters of light propagation. These features alter the coupling angles and distribution patterns, enabling more efficient light extraction from the waveguide while maintaining structural feasibility

Inventive Principle:

Principle #35Parameter changes

2Illumination intensity

If light extraction features are added to control light distribution, then illumination uniformity is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveillumination uniformityVSAvoidmanufacturing complexity

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The patent divides the light extraction function into discrete features distributed along the waveguide surface. Rather than requiring a uniformly complex structure throughout, light extraction features are segmented and placed at specific locations where light extraction is needed, achieving uniform illumination while simplifying manufacturing of individual components

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The waveguide structure is designed to serve multiple functions: light transmission, light redirection, and light extraction. By integrating these functions into a single multi-functional component rather than separate elements, the patent reduces the number of assembly steps and manufacturing processes required

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If light is directed in specific directions for targeted lighting, then light distribution control is improved, but light loss increases

Engineering Contradiction:

Improvelight distribution controlVSAvoidlight loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent employs light extraction features with varying geometries and orientations along the waveguide length. This dynamic variation in feature characteristics allows the system to adapt light extraction angles and intensities to match the specific illumination requirements of different zones, directing light where needed while minimizing losses through optimized angular distribution

Inventive Principle:

Principle #15Dynamics

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 improves light distribution by redirecting and extracting light effectively, achieving a more uniform and controlled illumination pattern with increased efficiency, suitable for applications requiring targeted lighting like roadways and parking lots.

Implementation Method 1

a body of optically transmissive material exhibiting a total internal reflection characteristic

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS12152756B2Lighting devices having optical waveguides for controlled light distribution

Publication Date: 2024.11.26 LED-IP MANAGEMENT LLC

AI summary

Lighting devices having optical waveguides for controlled light distribution are provided. A lighting device includes a housing, a light emitter disposed in the housing, and a waveguide at least partially disposed in an opening of the housing. The waveguide includes a light input surface defining coupling features, wherein the light emitter is disposed adjacent the light input surface and emits light into the coupling features. The waveguide further includes a light transmission portion disposed between the light input surface and a light extraction portion, wherein light from the light emitter received at the light input surface propagates through the light transmission portion toward the light extraction portion. The waveguide further includes the light extraction portion, which comprises at least one light redirection feature and at least one light extraction feature that cooperate to generate a controlled light pattern exiting the lighting device.