Plate-Shaped Light Guide Element for Uniform Direct and Indirect Illumination

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Solution Overview

Problem

Conventional lamps with plate-shaped light-guiding elements often exhibit dark spots when viewed from below due to reduced light emission through openings, which cannot be satisfactorily eliminated even with diffuser films, and lack efficient distribution of light for uniform direct and indirect lighting.

Innovation Solution

A lamp design featuring a plate-shaped light guide element with a large surface area, narrow edge surface area, and elongate light openings that act as reflectors, positioned close to the LED light source, allowing for efficient direct and indirect lighting without dark spots and potentially eliminating the need for a separate diffuser film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If openings are provided in the light guide element for indirect lighting, then indirect lighting is achieved, but dark spots appear when viewed from below

Engineering Contradiction:
Improveindirect lighting capabilityVSAvoidbrightness uniformity
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

A reflective cavity is introduced as an intermediary component between the light guide element and the observer. This cavity acts as a mediator that receives light from the openings and redirects it to illuminate the entire surface uniformly, eliminating dark spots while preserving indirect lighting capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution transitions from a two-dimensional opening structure to a three-dimensional reflective cavity system. By adding the vertical dimension with the cavity's reflective surfaces, light is redistributed from localized opening areas to a uniform three-dimensional illumination field, eliminating dark spots

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

2Illumination intensity

If a diffuser film is used to eliminate dark spots, then brightness uniformity improves, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvebrightness uniformityVSAvoidstructure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The diffuser film is completely removed from the system. Instead of adding this complex component, the invention extracts the light distribution function and implements it through the reflective cavity geometry, simplifying the overall structure while achieving uniform illumination

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The reflective cavity serves multiple functions simultaneously: it acts as a light guide, a diffuser, and a structural support element. This self-service approach eliminates the need for separate diffuser films and reduces overall device complexity

Inventive Principle:
Principle #25Self-service

3Ease of manufacture

If light is directed to the back or side of the luminaire housing to enhance color perception, then aesthetic quality improves, but direct lighting efficiency decreases

Engineering Contradiction:
Improveaesthetic qualityVSAvoidlighting efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

Different regions of the luminaire are assigned different functions: the front opening provides direct lighting efficiency, while the rear opening with reflective cavity provides aesthetic indirect lighting. Each local area is optimized for its specific purpose without compromising overall efficiency

Inventive Principle:
Principle #3Local quality

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 design achieves uniform brightness in direct lighting and enhances indirect lighting efficiency, eliminating dark spots and improving overall light distribution, making the luminaire appear brilliant and efficient.

Implementation Method 1

A light emitted by the LED light source falls into the light-guiding element at the edge and finally exits the light-guiding element downwards again

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

On the upper side of the light guide element there is a reflecting plate which has a plurality of openings 100 at the edge. Part of the light is emitted upwards via these openings 100

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3627042B1Luminaire with plate-shaped light guide element
Publication Date: 2021.06.16 ZUMTOBEL LIGHTING GMBH
  • EP3627042B1 patent drawingFigure 1~2
  • EP3627042B1 patent drawingFigure 3
  • EP3627042B1 patent drawingFigure 4

AI summary

A luminaire comprises a plate-shaped light guide element (1) and an LED light source (5) for emitting light, wherein the light enters the light guide element (1) at least partially via an edge area (4) and subsequently exits via a large surface area (3) to achieve direct illumination. Furthermore, a light guide element (7) extending along the edge area (4) with light openings (8) is provided, such that a portion of the light shines through the light openings (8) to achieve indirect illumination, the light guide element (7) also being designed to hold the LED light source (5).