Optical Waveguide Light Extraction for Directional Illumination

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Solution Overview

Problem

Existing optical waveguide systems for luminaries lack efficient control over light distribution, particularly in applications like roadway lighting, where directed illumination is needed while minimizing neighboring areas, and struggle to achieve symmetrical or asymmetrical 360-degree illumination patterns.

Innovation Solution

A lighting device with an optical waveguide featuring a body of optically transmissive material that includes a light input surface, a light transmission portion, and a light extraction portion with redirection and extraction features, allowing for controlled light distribution by deflecting and redirecting light to achieve specific illumination patterns, including directional components opposite the input direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional optical waveguide systems are used, then light can be transmitted through the waveguide, but efficient control over light distribution in specific directions is lacking

Engineering Contradiction:

Improvelight distribution controlVSAvoidwaveguide structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The waveguide is divided into distinct functional sections: a light input surface for receiving light, a light transmission portion for guiding light, and a light extraction portion with multiple extraction surfaces for different light directions. This segmentation allows independent optimization of each section's light control characteristics without redesigning the entire waveguide structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the waveguide are assigned different optical properties and functions. The light extraction portion includes first extraction surfaces for extracting light in one direction and second extraction surfaces for extracting light in opposite directions, with each surface optimized for its specific light extraction function. This local differentiation enables precise directional control of light distribution.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If light is emitted in all directions for 360-degree illumination, then comprehensive coverage is achieved, but inability to minimize illumination in specific neighboring regions occurs

Engineering Contradiction:

Improveillumination patternVSAvoidunwanted light in neighboring areas

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The light extraction portion is designed with differentiated extraction surfaces: first extraction surfaces optimized for extracting light toward the roadway, and second extraction surfaces optimized for extracting light in opposite directions away from roadside houses. This local functional differentiation enables the waveguide to provide comprehensive 360-degree illumination while simultaneously minimizing unwanted light in specific neighboring regions through direction-specific extraction optimization.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of using a single omnidirectional extraction surface that illuminates all directions equally, the invention inverts the approach by creating separate extraction surfaces for different directional requirements. The first extraction surfaces extract light for roadway illumination, while the second extraction surfaces extract light for areas requiring minimal illumination, effectively inverting the conventional single-surface design to achieve selective directional control.

Inventive Principle:

Principle #13The other way round (Inversion)

3Manufacturing precision

If directional light control features are added to the waveguide, then precise light distribution is achieved, but device complexity increases

Engineering Contradiction:

Improvelight distribution precisionVSAvoidwaveguide structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple light extraction functions are merged into a single integrated light extraction portion. The first extraction surfaces and second extraction surfaces are combined in one structure, allowing the waveguide to achieve precise directional light distribution control without requiring multiple separate optical components. This merging reduces overall system complexity while maintaining manufacturing precision.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The light extraction portion is designed as a multi-functional component that simultaneously performs multiple light extraction functions: extracting light toward the roadway through first extraction surfaces and extracting light in opposite directions through second extraction surfaces. This universal design enables a single waveguide structure to replace what would otherwise require multiple specialized optical elements, achieving precise light distribution without proportionally increasing device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 solution enables precise control over light distribution, allowing for targeted illumination while minimizing unwanted light in neighboring areas, and can produce symmetrical or asymmetrical 360-degree illumination patterns, enhancing the effectiveness of lighting applications.

Implementation Method 1

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.

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

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.

Methodology Applied

Scientific EffectLight refraction: Refraction

Implementation Method 3

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS11655950B2Lighting devices having optical waveguides for controlled light distribution

Publication Date: 2023.05.23 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.