Compact LED Array with Integrated Thermal Management

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Solution Overview

Problem

Conventional LED packages are limited in compactness and efficiency due to 'dead space' between LED packages, leading to reduced light diffusion and beam shaping capabilities, which complicates the construction of solid state lighting luminaires that require high light flux levels from a small optical source.

Innovation Solution

The use of chip-on-board (COB) technology with LED arrays mounted on a thermally conductive substrate, minimizing 'dead space' and incorporating primary and secondary lenses for enhanced light extraction, along with efficient thermal management to maximize first pass light emission and reduce thermal cross-talk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional LED packages are used with spacing between packages, then each package has adequate thermal management, but dead space reduces light diffusion and beam shaping capabilities

Engineering Contradiction:
Improvethermal managementVSAvoiddead space
Core Design Contradiction:
TemperatureVSArea of stationary object

Solution Approach 1:

Multiple LED chips are mounted in close proximity on a single substrate, merging what would traditionally be separate packaged LEDs into one integrated component. This eliminates the dead space between packages while maintaining compact thermal management through the shared substrate and reflector structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent arranges LED chips in a two-dimensional array on the substrate rather than spacing them linearly. This dimensional arrangement maximizes light extraction in multiple directions while maintaining compact footprint and efficient thermal pathways through the substrate.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If LED chips are mounted in a compact array, then light flux density increases, but thermal cross-talk between chips increases

Engineering Contradiction:
Improvelight flux densityVSAvoidthermal cross-talk
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The substrate is designed with differentiated thermal pathways, where regions near individual LED chips provide localized heat sinking to prevent thermal cross-talk. The reflector structure also incorporates localized cooling features that direct heat away from chip-to-chip interfaces while maintaining compact overall dimensions.

Inventive Principle:
Principle #3Local quality

3Loss of energy

If dead space is minimized for compactness, then light extraction efficiency improves, but manufacturing complexity increases

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidmanufacturing complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The LED array is segmented into modular chip units mounted on the substrate. Each chip can be positioned and tested independently, allowing for simplified manufacturing and replacement. The modular approach maintains compact spacing while enabling straightforward assembly processes.

Inventive Principle:
Principle #1Segmentation

4Reliability

If multiple LED packages are used to achieve high light flux, then individual package reliability is maintained, but overall device compactness decreases

Engineering Contradiction:
Improveindividual package reliabilityVSAvoiddevice compactness
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

Multiple LED chips are integrated onto a single substrate with a common reflector structure, merging what would traditionally be separate packaged LEDs. This maintains the reliability benefits of multiple emitters while achieving compact form factor by eliminating redundant packaging structures.

Inventive Principle:
Principle #5Merging (Combining)

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 approach results in compact, high-density LED components with improved light extraction efficiency, scalable for various applications, and efficient thermal management, enabling the delivery of high light flux levels while maintaining a compact form factor.

Implementation Method 1

an array of light emitting diodes (LEDs) mounted on a thermally conductive substrate

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

incorporating primary and secondary lenses for enhanced light extraction

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

Light emitting diodes (LED or LEDs) are solid state devices that convert electric energy to light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2591280B1Compact optically efficient solid state light source with integrated thermal management
Publication Date: 2017.12.13 WOLFSPEED INC
  • EP2591280B1 patent drawingFigure 1~3
  • EP2591280B1 patent drawingFigure 4~6
  • EP2591280B1 patent drawingFigure 7~9

AI summary

A compact and efficient LED array lighting component comprising a circuit board with an array of LED chips mounted on it and electrically interconnected. A plurality of primary lenses is included, each of which is formed directly over each LED chip and/or a sub-group of the LED chips. A heat sink is included with the circuit board mounted to the heat sink so that heat from the LED chips spreads into the heat sink. In some embodiments the circuit board can be thermally conductive and electrically insulating. Method of forming an LED component are also disclosed utilizing chip-on-board mounting techniques for mounting the LED chips on the circuit board, and molding of the primary lenses directly over the LED chips individually or in sub-groups of LED chips.