Bent Optical Waveguide for Homogeneous LED Luminaire Design

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Solution Overview

Problem

Designing an LED lamp with a large light-emitting surface while maintaining an inconspicuous housing is a challenge, as existing solutions often compromise on light output due to the placement and design of additional components like operating devices.

Innovation Solution

A curved light guide with a convex and concave surface area is used, where the concave surface surrounds the additional lamp components, and a transparent cover with an optically diffusing film is applied to the convex surface, minimizing obstruction and enhancing light distribution, with a reflector element to increase efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If additional luminaire components (e.g., control gear) are arranged inside the light guide, then device complexity is reduced and space is saved, but light output and light-emitting surface area are obstructed

Engineering Contradiction:
Improvestructural complexityVSAvoidlight output
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

The control gear is nested within the hollow interior space of the curved light guide, utilizing the light guide's own structure as housing space. This nesting arrangement saves overall space and reduces additional housing requirements while the light guide's curvature ensures minimal obstruction to light output through its strategically positioned convex surface area.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Volume of moving object

If the light guide is curved to surround additional components, then space utilization is improved and housing size is reduced, but manufacturing complexity increases

Engineering Contradiction:
Improvehousing volumeVSAvoidmanufacturing ease
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The light guide is designed with a curved configuration featuring a convex surface area for light output and a concave surface area that surrounds the control gear. This curvature enables compact space utilization and efficient volume usage while the design maintains manufacturability through standardized profiling processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Area of stationary object

If the light-emitting surface is extended to the upper boundary of the luminaire, then light-emitting area is increased, but mounting complexity increases

Engineering Contradiction:
Improvelight-emitting surface areaVSAvoidmounting ease
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The transparent cover forming the light-emitting surface is segmented from the main light guide structure and connected via a snap-fit connection mechanism. This segmentation allows the cover to be easily mounted and dismounted while extending the light-emitting surface to the upper boundary of the luminaire, achieving both increased light output area and ease of installation.

Inventive Principle:
Principle #1Segmentation

4Illumination intensity

If a transparent cover with optically diffuse film is added to enhance light homogeneity, then light quality is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvelight homogeneityVSAvoidcomponent quantity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

An optically diffuse film is introduced as an intermediary element between the light guide's convex surface area and the transparent cover. This film mediates the light transmission process by diffusing the light to achieve homogeneous light emission, while being integrated into the existing cover structure to minimize additional complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves a high-quality, homogeneous light output with a large light-emitting surface, reducing the visibility of non-illuminating surfaces and improving installation ease, while maintaining a compact form factor.

Implementation Method 1

an optically diffuse film is arranged between the convex surface area of the light guide and the transparent cover

Methodology Applied
Scientific EffectOptical diffusion: Scattering

Implementation Method 2

the cover is held on a support element by means of a snap-fit connection, wherein the cover has a snap-fit hook at each of its two upper end regions, which permanently engages the support element in a snap-fit manner to form the connection

Methodology Applied
Scientific EffectMechanical snap-fit connection: Mechanical Fastener

Implementation Method 3

a light guide for directing the light, wherein the light guide is curved in such a way that it has a convex surface area and a concave surface area

Methodology Applied
Scientific EffectLight guidance: Waveguide (optics)

Data Source

PatentEP3218648B1LED luminaire comprising a bent optical waveguide
Publication Date: 2020.05.20 ZUMTOBEL LIGHTING GMBH
  • EP3218648B1 patent drawingFigure 1
  • EP3218648B1 patent drawingFigure 2
  • EP3218648B1 patent drawingFigure 3

AI summary

In a luminaire comprising an LED light source (1) for generating light, an optical waveguide (2) for guiding the light, and an additional luminaire component (3), the optical waveguide (2) is bent in such a way as to have a convex surface region (4) and a concave surface region (5) and is arranged in such a way that the concave surface region (5) thereof at least partially surrounds the additional luminaire component (3).