Plastic LED Street Light Thermal Management

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Solution Overview

Problem

Existing LED street lights face challenges in heat dissipation due to the temperature sensitivity of LEDs, leading to complex and expensive designs with aluminum components, which are heavy, costly, and prone to dirt and moisture issues, while plastic alternatives struggle with low thermal conductivity and strength.

Innovation Solution

A plastic LED street light design featuring a flat printed circuit board with evenly distributed LEDs, a transparent lens plate for optics, and a plastic housing that encloses the circuit board, allowing for direct heat dissipation through both the housing and lens plate, with optional ribs for stabilization and easy cleaning, and a modular structure for efficient lighting and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If aluminum components with cooling fins are used for heat dissipation, then heat dissipation performance is improved, but weight and material cost increase

Engineering Contradiction:
Improveheat dissipation performanceVSAvoidweight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent changes the material parameter from aluminum to plastic, specifically using plastic with added thermal conductive particles (aluminum oxide, boron nitride, or silicon carbide) to achieve both lightweight construction and adequate heat dissipation performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite material by combining plastic base material with thermal conductive particles (aluminum oxide, boron nitride, or silicon carbide) to achieve a material that is both lightweight and thermally conductive, resolving the contradiction between weight and heat dissipation performance

Inventive Principle:
Principle #40Composite materials

2Temperature

If aluminum components are used for heat dissipation, then heat dissipation performance is improved, but material cost and handling difficulty increase

Engineering Contradiction:
Improveheat dissipation performanceVSAvoidhandling during assembly
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The patent changes the material from aluminum to plastic, which is easier to handle during assembly and reduces the burden on mounting structures, while maintaining heat dissipation performance through thermal conductive additives

Inventive Principle:
Principle #35Parameter changes

3Weight of moving object

If plastic housing is used instead of aluminum, then weight and material cost are reduced, but thermal conductivity decreases

Engineering Contradiction:
ImproveweightVSAvoidthermal conductivity
Core Design Contradiction:
Weight of moving objectVSTemperature

Solution Approach 1:

The patent creates a composite material by combining plastic base material with thermal conductive particles (aluminum oxide, boron nitride, or silicon carbide) to achieve a material that is both lightweight and thermally conductive, resolving the contradiction between weight and heat dissipation performance

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the thermal conductivity parameter of plastic by adding thermal conductive particles, achieving adequate heat dissipation performance while maintaining the lightweight advantage of plastic

Inventive Principle:
Principle #35Parameter changes

4Temperature

If complex metal heat dissipation structure is used, then heat dissipation performance is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improveheat dissipation performanceVSAvoidstructural complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent changes the material from metal to plastic with thermal conductive additives, simplifying the overall structure by eliminating the need for separate metal heat sinks and cooling fins, thus reducing device complexity while maintaining heat dissipation performance

Inventive Principle:
Principle #35Parameter changes

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

This design achieves effective heat dissipation, stability, and cost-effectiveness by distributing heat evenly through the plastic components, reducing material costs and weight, while maintaining precise lighting control and resistance to environmental influences.

Implementation Method 1

the heat of the LEDs is first distributed and dissipated via metal parts and only then is dissipated via a heavily fissured plastic housing

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2924334B1LED street light
Publication Date: 2019.07.24 SWARCO FUTURIT VERKEHRSSIGNALSYSTEME GES MBH
  • EP2924334B1 patent drawingFigure 1
  • EP2924334B1 patent drawingFigure 2~5
  • EP2924334B1 patent drawingFigure 6~7

AI summary

A street light using LED technology, primarily made of plastic, is presented, which nevertheless exhibits good thermal management. The circuit board (1), with good thermal conductivity properties and uniformly distributed SMD LEDs (2), is covered on the LED side by an adjacent lens plate (3) which integrates recesses (4) for each LED (2) and optics (5, 6). The back of the lens plate rests against a housing (7). The lens plate (3) and housing (7) are preferably made of polycarbonate and are directly exposed to the outside. The heat generated is distributed evenly within the circuit board (1) and dissipated to the outside on both sides. To protect the circuit board (1) from the elements, the lens plate (3) and the housing (7) are tightly connected. A container (11) is attached to the housing (7), which houses the connections, the ballast, fuses, and communication modules, as well as an adjustable adapter (12) for cantilever mounting.The very thin construction can be mechanically reinforced by ribs (8, 8a).