LED Downlight Reflector and Diffuser Glare Control

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Solution Overview

Problem

Existing downlight fixtures using incandescent or fluorescent lamps are inefficient and pose safety hazards, whereas LED lamps offer better efficiency and safety but often lack clear cutoff and minimal glare.

Innovation Solution

An LED downlight fixture design featuring an array of LEDs in thermal communication with a heat sink, a multi-piece reflector assembly with a diffuser positioned between the reflectors to create a light exit passageway, and a non-conductive lens to inhibit contact, providing ample light cut-off and reduced glare.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If LED lamps are used in downlight fixtures, then energy efficiency and safety are improved, but clear cutoff and glare control deteriorate

Engineering Contradiction:

Improveenergy efficiencyVSAvoidglare

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

A diffuser is introduced as an intermediary element between the LED light source and the surrounding environment. The diffuser scatters and softens the light output, effectively reducing glare and improving cutoff characteristics while maintaining the energy efficiency benefits of LED technology.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies different optical properties to different parts of the lighting system. The LED array provides focused, efficient light generation, while the diffuser applies a different local quality (scattering and softening) to the light as it exits, creating zones with different optical characteristics to optimize both efficiency and glare control.

Inventive Principle:

Principle #3Local quality

2Reliability

If LED lamps are used in downlight fixtures, then safety and economy are improved, but clear cutoff characteristics deteriorate

Engineering Contradiction:

ImprovesafetyVSAvoidcutoff characteristics

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The diffuser serves as a mediator that modifies the light distribution pattern. It creates a smooth transition between illuminated and non-illuminated areas, providing clear cutoff characteristics that prevent light from spilling into unwanted areas while maintaining the safety advantages of LED technology.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If incandescent or fluorescent lamps are used in downlight fixtures, then clear cutoff characteristics are maintained, but energy efficiency and safety deteriorate

Engineering Contradiction:

Improvecutoff characteristicsVSAvoidenergy efficiency

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent changes the fundamental parameters of the light source from incandescent or fluorescent to LED technology. This parameter change dramatically improves energy efficiency and safety. The diffuser is then used to adjust the optical distribution parameters, restoring clear cutoff characteristics that were present in traditional lighting systems.

Inventive Principle:

Principle #35Parameter changes

4Duration of action of stationary object

If LED lamps are used in downlight fixtures, then longevity is improved, but optical control deteriorates

Engineering Contradiction:

ImprovelifespanVSAvoidglare control

Core Design Contradiction:

Duration of action of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The diffuser acts as a permanent optical intermediary that works continuously with the LED light source throughout its extended operational life. This intermediary element ensures consistent glare control and cutoff characteristics are maintained over the full lifespan of the LED fixture, addressing the optical control challenges associated with long-lived LED systems.

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

The design enhances light efficiency and reduces glare, offering a safer and more economical LED-based downlight solution with clear cutoff characteristics.

Implementation Method 1

an array of LEDs in thermal connectivity with a heatsink

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a multi-piece reflector assembly with a diffuser positioned between the reflectors to create a light exit passageway

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 3

a diffuser positioned proximal to and extending across the second aperture of the first reflector and the first aperture of the second reflector

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentUS8070328B1LED downlight

Publication Date: 2011.12.06 SIGNIFY HOLDING BV

AI summary

An LED downlight fixture comprises an array of LEDs in thermal connectivity with a heatsink, the array of LEDs positioned adjacent a first aperture of a multi-piece reflector assembly, the multi-piece reflector assembly including a first reflector having the first aperture disposed in an upper portion of the first reflector and an opposed larger second aperture in a lower portion of the first reflector, a second reflector having a first aperture positioned adjacent the second aperture of the first reflector and a second aperture opposite the first aperture of the second reflector and defining a light exit passageway, a diffuser positioned proximal to and extending across the second aperture of the first reflector and the first aperture of the second reflector.