LED Optical Device with Light Guide for Glare Reduction

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Solution Overview

Problem

Existing LED lighting appliances face challenges in achieving low luminance to minimize glare while maintaining excellent thermal dissipation and avoiding surface yellowing, with current designs either suffering from high luminance and glare or complex construction.

Innovation Solution

A hybrid optical device with a central light input zone and peripheral elongated portions featuring a light guide and specific geometrical structures, such as prisms and tetrahedrons, that control light extraction to create a photometric solid for ordinary and emergency lighting, ensuring 100% internal reflection and reduced direct light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a continuous panel of LEDs is used for direct light diffusion, then glare is minimized due to low luminance, but the structure becomes complex and surface yellowing occurs

Engineering Contradiction:
ImproveglareVSAvoidconstructive complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The LED panel is segmented into multiple individual LED diodes arranged in a grid pattern, with each LED surrounded by a reflective cup structure. This segmentation allows for simplified manufacturing while maintaining the diffuse light distribution that reduces glare, avoiding the complexity of continuous panel structures.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A reflective cup structure acts as an intermediary element between the LED diode and the surrounding environment. This cup reflects light from the LED in multiple directions, creating diffuse illumination that reduces glare while simplifying the overall structure compared to continuous panels.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a continuous panel of LEDs is used for direct light diffusion, then glare is minimized, but thermal dissipation of LED diodes becomes poor

Engineering Contradiction:
ImproveglareVSAvoidthermal dissipation
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The LED diode is extracted from the continuous panel structure and mounted individually within a reflective cup. This extraction allows for improved thermal management through the cup structure which can be thermally coupled to heat sinks or dissipative materials, while still achieving diffuse light distribution.

Inventive Principle:
Principle #2Taking out (Extraction)

3Temperature

If central lenses are used in LED lighting appliances, then thermal dissipation is excellent and construction is simple, but luminance becomes high causing glare phenomena

Engineering Contradiction:
Improvethermal dissipationVSAvoidglare
Core Design Contradiction:
TemperatureVSObject-affected harmful factors

Solution Approach 1:

The reflective cup structure provides localized light control around each LED diode, directing light in specific patterns that reduce luminance in the viewer's direction while maintaining thermal dissipation through the cup structure. This local quality approach allows for glare reduction without sacrificing thermal management.

Inventive Principle:
Principle #3Local quality

4Device complexity

If central lenses are used in LED lighting appliances, then construction is simple and thermal dissipation is excellent, but surface yellowing phenomena occur

Engineering Contradiction:
Improveconstructive simplicityVSAvoidsurface yellowing
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The reflective cup structure uses simple, stable materials that resist yellowing degradation. The design avoids complex multi-material constructions that are prone to yellowing, opting instead for a straightforward metallic or coated structure that maintains its optical properties over time while remaining constructively simple.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 medium-low luminance to reduce glare, excellent thermal dissipation, and prevents surface yellowing, while maintaining a simple and reliable construction, effectively addressing the limitations of existing LED lighting designs.

Implementation Method 1

substantially 100% of the light emitted by the LED light source is guided by total internal reflection inside the elongated portions 12

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP4081735B1Optical device for LED lighting appliances
Publication Date: 2023.11.22 BEGHELLI SPA
  • EP4081735B1 patent drawingFigure 1~3
  • EP4081735B1 patent drawingFigure 4~6

AI summary

Described is an optical device (10) for LED lighting appliances, comprising a central zone (11 ), wherein an LED light source is located, and peripheral elongated portions (12), specular with respect to the central zone (10), each of which having internally a light guide (13) configured to bring (F) the light coming from the light source into predetermined zones of the optical device (10) where at least a portion of light can be extracted in a controlled manner and according to predetermined directions; this is in order to obtain a photometric solid designed for ordinary and emergency lighting applications and an illuminated surface which is large and such as to reduce glare.