LED Downlight Secondary Reflector Ring Light Distribution

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Solution Overview

Problem

Downlights with LEDs experience a dark area in the center of their light dispersion graph due to inefficient light distribution, and heat buildup in the plenum above the ceiling reduces LED performance and life, as they operate less efficiently at higher temperatures.

Innovation Solution

An LED downlight design featuring a primary reflector with a heat sink for heat dissipation, a secondary reflective ring with a beveled inner surface to redirect light centrally, and a mixing chamber with a phosphor system to enhance light distribution and temperature management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If LEDs are positioned in deep round reflectors, then the downlight provides efficient heat dissipation and compact structure, but a dark area appears in the center of the light dispersion graph

Engineering Contradiction:

Improvereflector shapeVSAvoidcenter illumination

Core Design Contradiction:

ShapeVSIllumination intensity

Solution Approach 1:

The reflector is segmented into two distinct components: a primary reflector for heat dissipation and light collection, and a secondary reflector ring for redirecting light to the center area. This segmentation allows each component to perform its specialized function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The secondary reflector ring acts as an intermediary element between the LED light source and the center area below. It intercepts light that would otherwise miss the center and redirects it downward, mediating the light distribution to eliminate the dark spot.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If LEDs operate in the plenum area above the ceiling, then the downlight structure is simplified, but heat builds up and reduces LED efficiency and life

Engineering Contradiction:

Improveluminaire structureVSAvoidLED operating temperature

Core Design Contradiction:

Device complexityVSTemperature

Solution Approach 1:

Heat is extracted from the LED operating environment through the primary reflector, which is designed to conduct and dissipate heat away from the LED components. This separates the heat management function from the light generation function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The primary reflector serves multiple functions: it reflects light, provides structural support, and acts as a heat dissipation pathway. By making the reflector multi-functional, the overall luminaire structure remains simple while effective heat management is achieved.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Illumination intensity

If a secondary reflector ring is added to improve light distribution, then center illumination is enhanced, but device complexity increases

Engineering Contradiction:

Improvecenter illuminationVSAvoidreflector structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The secondary reflector ring is merged with the primary reflector assembly, sharing the same mounting structure and optical path. This integration minimizes the increase in device complexity while achieving the light redistribution function.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Instead of trying to modify the primary reflector to redirect light centrally, the invention uses a secondary reflector ring that works in the opposite manner - it intercepts light traveling outward and redirects it inward toward the center, achieving the desired effect through inverse action.

Inventive Principle:

Principle #13The other way round (Inversion)

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

Improves light distribution by redirecting light to the center area, increasing illumination uniformity and efficiency, while the dual heat dissipation mechanism extends LED life and performance by transferring heat to a cooler area beneath the luminaire.

Implementation Method 1

a secondary reflective ring positioned beneath the LED printed circuit board assembly and within the primary reflector housing, the secondary reflector ring supporting the optical assembly and improving light distribution... The LED downlight wherein the inner beveled surface directs light downwardly centrally beneath the downlight

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

a downlight luminaire having a first heat dissipation subassembly and a reflector which is in direct thermal communication with a LED printed circuit board assembly so as to dissipate heat through two structures

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS8602601B2LED downlight retaining ring

Publication Date: 2013.12.10 SIGNIFY HOLDING BV

AI summary

An LED downlight comprises a primary reflector having an upper end and an open lower end, an LED printed circuit board assembly disposed in the upper end of the reflector, an optical assembly positioned beneath the LED printed circuit board assembly, a secondary reflective ring positioned beneath the LED printed circuit board assembly and within the primary reflector housing, the secondary reflector ring supporting the optical assembly and improving light distribution.