Light Guide Device with Interleaved Extraction Features

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Solution Overview

Problem

Existing light guide devices for illumination and display purposes suffer from low angular uniformity, especially when curved or bent, requiring additional components like diffusers and reflectors to achieve uniform light output, which increase cost and thickness.

Innovation Solution

A light guide device with an interleaved pattern of first and second extraction features on its surface, which redirects guided light to produce a uniform angular luminance profile without the need for diffusers or reflectors, maintaining uniformity even when the device is non-planar.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional extraction features are used on planar light guides, then light extraction is achieved, but angular luminance uniformity deteriorates

Engineering Contradiction:

Improveangular luminance uniformityVSAvoidextraction feature pattern

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The extraction features are divided into multiple types (first extraction features and second extraction features) with different geometries and optical properties. Each type extracts light at different angles and positions, and their combined effect produces uniform angular luminance distribution across the light guide surface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the light guide surface are equipped with different types of extraction features tailored to local requirements. The first and second extraction features are selectively placed in different zones to optimize light extraction characteristics for each region, achieving overall uniformity.

Inventive Principle:

Principle #3Local quality

2Illumination intensity

If diffusers and reflectors are added to improve angular uniformity, then luminance uniformity improves, but device thickness and manufacturing cost increase

Engineering Contradiction:

Improveangular luminance uniformityVSAvoiddevice thickness

Core Design Contradiction:

Illumination intensityVSLength of stationary object

Solution Approach 1:

The patent extracts and integrates the light redistribution function directly into the extraction features on the light guide surface, eliminating the need for separate diffuser and reflector components. The extraction features themselves perform the function of redistributing light to achieve uniform angular luminance.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The light extraction and light redistribution functions are merged into a single integrated structure - the extraction features with specific patterns. This combines multiple functions (extraction, redirection, and uniformity control) into one component system, reducing overall device complexity and thickness.

Inventive Principle:

Principle #5Merging (Combining)

3Adaptability or versatility

If the light guide is curved or bent for application flexibility, then adaptability improves, but angular luminance uniformity deteriorates

Engineering Contradiction:

Improveflexibility for curved applicationsVSAvoidangular luminance uniformity

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The extraction feature pattern is designed to maintain its optical functionality under dynamic conditions including bending and curving. The interleaved arrangement of different extraction feature types creates a robust system that adapts to various light guide configurations while preserving angular luminance uniformity.

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

The solution achieves high uniformity in angular luminance and spatial luminance, reducing manufacturing costs and thickness, while maintaining performance when the device is curved or bent, enhancing its application in various lighting and display scenarios.

Implementation Method 1

An alternative solution is to use refractive effects, where the shape of the exit surface is locally modified on small scale such that the effective angle of incidence of the guided light is changed below the critical angle and light can therefore exit in accordance with Snell's Law.

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

The light 4 generated by the light source 2 then propagates within the planar light guide 3 due to the effects of total internal reflection.

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

Reflection involves the light 4 interacting with a reflecting material on the surface of the light guide 3 which is absorbed and then re-emitted and so breaks down the effect of total internal reflection.

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS9010983B2Light guide device

Publication Date: 2015.04.21 DESIGN LED PRODS

AI summary

A light guide device for illumination, lighting and display purposes that exhibits an output light having a predetermined, and preferably uniform, angular luminance profile is described. The device comprises a light guide (13) suitable for guiding light coupled thereto and a plurality of extraction features (10, 11) located on one or more surfaces of the light guide. The plurality of extraction features comprises an interleaved pattern of first (11) and second extraction features the arrangement of which provides a means for defining the predetermined angular and spatial luminance profiles for the output light. The device allows for a uniform angular luminance profile to be produced that is maintained even when the light guide is curved or bent.