Planar Optical Waveguide Lighting Device

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Solution Overview

Problem

Existing lighting arrangements for pendant lights and similar fixtures struggle to achieve both direct and indirect lighting effects efficiently, often requiring multiple light sources and complex optical elements, which increases cost and complexity.

Innovation Solution

A flat light guide with a side contour that allows light to be coupled in laterally and decoupled in multiple directions using strategically positioned coupling and decoupling areas, enabling efficient emission of light in various spatial directions with a single or few light sources, including indirect and direct lighting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple light sources are used to achieve both direct and indirect lighting effects, then lighting functionality is improved, but device complexity and cost increase

Engineering Contradiction:
Improvelighting functionalityVSAvoidnumber of light sources
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The light guide serves multiple functions: it guides light from the light source, provides direct illumination through its front surface, and enables indirect lighting through lateral decoupling areas. This multi-functionality eliminates the need for separate light sources for direct and indirect lighting, reducing device complexity while maintaining versatile lighting capabilities

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention utilizes the lateral dimension of the light guide by creating decoupling areas on the side contour. Light is coupled into the light guide and then decoupled laterally through these side areas, enabling indirect lighting in a different spatial dimension. This approach allows a single light source to provide both direct and indirect lighting by exploiting the three-dimensional light propagation within the light guide

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If additional optical elements are added to achieve multiple lighting effects, then lighting versatility is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvelighting effectsVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The light guide features locally differentiated properties: the front surface has high transmissivity for direct lighting, while specific lateral regions have reduced transmissivity or enhanced reflectivity to create decoupling areas for indirect lighting. These local property variations are achieved through simple manufacturing techniques like selective coating or structural modification, avoiding complex optical elements

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention merges the functions of multiple optical elements into the light guide itself. The light guide integrates light guidance, light distribution, and light decoupling functions by incorporating decoupling areas directly into its structure. This consolidation eliminates the need for separate reflectors, diffusers, or redirectors, simplifying manufacturing while achieving multiple lighting effects

Inventive Principle:
Principle #5Merging (Combining)

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 solution allows for flexible and cost-effective lighting arrangements that can produce both indirect and direct lighting effects with reduced need for multiple light sources, providing efficient and homogeneous illumination.

Implementation Method 1

The light guide is configured to propagate light laterally by total reflection at the front and back within the light guide

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The in-coupling area is formed by a portion of the side contour and the light guide has out-coupling areas, which are formed by at least two essentially opposite partial areas of the side contour, in order to laterally out-couple the light

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3090292B1Lighting device
Publication Date: 2018.12.12 ZUMTOBEL LIGHTING GMBH
  • EP3090292B1 patent drawingFigure 1~3
  • EP3090292B1 patent drawingFigure 4~6
  • EP3090292B1 patent drawingFigure 7~8

AI summary

The invention relates to a luminaire arrangement (20) comprising a planar optical waveguide (10) and at least one light source (2a, 2b), wherein the optical waveguide (10) has a front side (10b) and a rear side (10c) and a side contour (10a) connecting the front and rear sides (10b, 10c), and wherein the light source (2a, 2b) is arranged in a manner optically connected to a coupling-in region (11a, 11b) of the optical waveguide for coupling light from the light source (2a, 2b) into the optical waveguide (10), in the case of which the coupling-in region (11a, 11b) is formed by a partial region of the side contour (10a) and the optical waveguide (10) has coupling-out regions (13a, 13b) formed by at least two substantially opposite partial regions of the side contour (10a) in order to laterally couple out the light from the at least one light source (2a, 2b) via the coupling-out regions (13a, 13b). Such a luminaire arrangement (20) can be used to obtain indirect lighting in a simple manner, in particular in conjunction with direct lighting. Furthermore, the invention relates to a luminaire (1), in particular a pendant luminaire or surface-mounted luminaire, comprising such a luminaire arrangement (20).