LED Lamp Diffuser Geometry for Homogeneous Light Distribution

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Solution Overview

Problem

Existing LED lamps lack optimal integration with reflectors, particularly specular reflectors, and fail to provide homogeneous light distribution when used in various lighting applications, leading to inefficient light utilization and potential multiple reflections.

Innovation Solution

A lamp design featuring LED elements thermally connected to a heat sink, housed within a sealed unit with a translucent diffuser element that has a unique cross-sectional geometry, ensuring diffuse scattering and homogeneous light distribution, optimized for use in reflector lamps by aligning the diffuser element angle with the lamp shielding angle to minimize reflections and maximize space utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If LED elements are used as light sources in a lamp, then energy efficiency and lamp life are improved, but homogeneous light distribution and optimal integration with reflectors are not achieved

Engineering Contradiction:
Improveenergy efficiencyVSAvoidhomogeneous light distribution
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent applies local quality by creating a diffuser element with specifically engineered local optical properties. The diffuser contains scattering particles distributed throughout its volume, creating localized scattering centers that collectively achieve homogeneous light distribution. The varying refractive indices of different materials (diffuser material vs. scattering particles) create the desired light scattering effect in specific regions while maintaining overall optical transparency.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The diffuser element serves as an intermediary between the LED light source and the external environment. It mediates the transition from point-source LED emission to homogeneous area illumination by scattering light throughout its volume. The scattering particles within the diffuser act as intermediate scattering centers that redirect light paths, achieving uniform light distribution without requiring direct modification of the LED elements themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If LED elements are mounted on a substrate, then ease of assembly is improved, but thermal management becomes problematic

Engineering Contradiction:
Improveease of assemblyVSAvoidthermal management
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent extracts the thermal management function from the mounting substrate by introducing a dedicated heat sink component. The heat sink is thermally coupled to the LED elements through thermal conductive material, separating the mechanical support function (substrate) from the thermal dissipation function (heat sink). This extraction allows each component to be optimized independently for its specific function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Thermal conductive material acts as an intermediary between the LED elements and the heat sink, facilitating efficient heat transfer. This intermediary layer ensures optimal thermal coupling while allowing for different geometries and materials on either side, bridging the gap between the small LED mounting area and the larger heat dissipation surface of the heat sink.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a sealed lamp housing is used, then protection against soiling and damage is improved, but light extraction efficiency may be reduced

Engineering Contradiction:
Improveprotection against soiling and damageVSAvoidlight extraction efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies the color changes principle by using a diffuser material that is transparent or translucent rather than opaque. This allows light to pass through while still providing protection. The scattering particles within the diffuser modify the light's path and distribution but not its fundamental transmission property, maintaining light extraction efficiency while achieving the protective function of sealing.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The diffuser element is a composite material combining a transparent or translucent base material with dispersed scattering particles. This composite structure provides both the protective sealing function and the light diffusing function simultaneously. The scattering particles are distributed throughout the volume of the base material, creating a unified component that addresses both protection and light extraction requirements.

Inventive Principle:
Principle #40Composite materials

4Ease of operation

If scattering particles are provided within the diffuser material, then homogeneous light distribution is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvehomogeneous light distributionVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies the porous materials principle by incorporating scattering particles within the volume of the diffuser material, creating a particulate composite structure. This approach simplifies manufacturing compared to creating complex surface micro-optics, as the scattering particles can be mixed into the material during fabrication processes such as injection molding or extrusion, allowing homogeneous light distribution to be achieved through a relatively simple manufacturing step.

Inventive Principle:
Principle #31Porous materials

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 efficient light distribution and utilization, reducing multiple reflections while maintaining long lamp life and high luminous efficacy, suitable for diverse lighting applications, including those with specular reflectors.

Implementation Method 1

it is a translucent, diffusely scattering element. Such an element can consist, for example, of a material such as glass or plastic, in which scattering particles are provided within the material (volume scattering)

Methodology Applied
Scientific EffectDiffuse scattering: Scattering

Implementation Method 2

They are attached to the lamp housing, wherein they are preferably thermally connected to a heat sink

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

It is also possible for the diffuser element to be coated on the inside with a luminophore that visibly lights up as a result of UV excitation

Methodology Applied
Scientific EffectLuminescence: Luminescence

Data Source

PatentEP2207996B1LED lamp with diffuser
Publication Date: 2020.05.27 SITECO GMBH
  • EP2207996B1 patent drawingFigure 1~3
  • EP2207996B1 patent drawingFigure 4~6
  • EP2207996B1 patent drawingFigure 7~9

AI summary

The invention relates to a lamp 10 comprising one or a plurality of LED elements 12 and a housing with electrical and mechanical connection means 18, wherein the housing has a light exit region with a light-transmissive terminating element 20. The terminating element is an optical diffuser element 20 of a form in which the wall has in cross section two opposite, straight sections 26 running towards one another.