COB LED Light Engine Thermal Management

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing LED-based illumination systems suffer from poor performance, short lifespan, and high costs due to the use of prepackaged LED devices, which lack efficient thermal management and have additional components that increase thermal impedance and reduce light collection efficiency.

Innovation Solution

The use of 'Chip-on-Board' (COB) technology with high thermal conductivity substrates and compact non-imaging optics, which reduces thermal impedance, increases packing density, and allows for more efficient light collection and monitoring, combined with reflective apertures for enhanced brightness in Etendue-preserving systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If prepackaged LED devices are used, then ease of manufacture is improved, but thermal impedance increases and light collection efficiency decreases

Engineering Contradiction:
Improveease of manufactureVSAvoidthermal impedance
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent extracts the LED die from its prepackaged housing and mounting structure, placing it directly onto a heat sink with high thermal conductivity. This removal of intermediate packaging layers eliminates the thermal impedance barriers that would otherwise be present in prepackaged devices, while the direct mounting simplifies the overall structure despite the unconventional approach.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If prepackaged LED devices are used, then ease of manufacture is improved, but light collection efficiency decreases

Engineering Contradiction:
Improveease of manufactureVSAvoidlight collection efficiency
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent extracts the LED die from its prepackaged housing and mounting structure, placing it directly onto a heat sink with high thermal conductivity. This removal of intermediate packaging layers eliminates the thermal impedance barriers that would otherwise be present in prepackaged devices, while the direct mounting simplifies the overall structure despite the unconventional approach.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent positions the LED die in a planar configuration directly on the heat sink surface, eliminating the vertical stacking and encapsulation of prepackaged devices. This dimensional reorganization allows collection optics to access the LED emitting surface more effectively from multiple angles, significantly improving light collection efficiency while maintaining manufacturing feasibility.

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

3Temperature

If COB technology is used, then thermal impedance is reduced, but device complexity increases

Engineering Contradiction:
Improvethermal impedanceVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the LED die mounting function, thermal management function, and electrical connection function into a single integrated COB structure. The LED dies are mounted directly onto a copper or aluminum core PCB that serves simultaneously as the mounting substrate, heat sink, and electrical trace carrier, eliminating the need for separate heat sink components and reducing overall device complexity despite the advanced manufacturing requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The COB substrate performs multiple functions simultaneously: it provides mechanical support for the LED dies, conducts heat away from the junctions, provides electrical connections through integrated traces, and serves as the mounting platform for the collection optics. This multi-functionality reduces the total component count and simplifies the overall device architecture.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Use of energy by moving object

If higher packing density of LED die is used, then efficiency increases, but heat dissipation requirements increase

Engineering Contradiction:
ImproveefficiencyVSAvoidheat dissipation
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent merges the LED die mounting function, thermal management function, and electrical connection function into a single integrated COB structure. The LED dies are mounted directly onto a copper or aluminum core PCB that serves simultaneously as the mounting substrate, heat sink, and electrical trace carrier, eliminating the need for separate heat sink components and reducing overall device complexity despite the advanced manufacturing requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs composite material structures, particularly the copper or aluminum core PCB that combines high thermal conductivity materials with electrical insulation layers and conductive traces. This composite construction enables simultaneous achievement of high packing density for improved efficiency and effective heat dissipation through the thermally conductive core, resolving the contradiction between increased efficiency and heat management requirements.

Inventive Principle:
Principle #40Composite 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

This configuration results in a more compact, efficient, and cost-effective LED light engine with improved thermal and optical performance, capable of maintaining constant light output and temperature monitoring, suitable for high-brightness applications like surgical illumination and fiber optic coupling.

Implementation Method 1

The LED die or die arrays are mounted to a high thermal conductivity circuit board comprising COB technology

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

high efficiency compact non-imaging optics

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

reflective apertures for enhanced brightness in Etendue-preserving systems

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

photosenors for light monitoring

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2452120B1Light emitting diode light engine
Publication Date: 2016.11.23 INNOVATIONS IN OPTICS INC
  • EP2452120B1 patent drawingFigure 1~2
  • EP2452120B1 patent drawingFigure 3~4
  • EP2452120B1 patent drawingFigure 5~6

AI summary

An LED light engine system that incorporates light emitting diodes (LEDs) with one or more distinct colors, including broad band white light obtained from phosphors or a combination of LED die colors and LED die coated phosphors. The LED die or die arrays are mounted to a high thermal conductivity circuit board comprising COB technology which can include both the LED die and electronic drive components resulting in a compact and reliable design with improved thermal and optical performance. High efficiency non-imaging collection optics are coupled to the LEDs to efficiently capture substantially all of the light which they emit and reformat it as an output with substantially the same ntendue as that of the LED to provide high brightness sources. Feedback from the output back to a photosensor on the circuit board is provided to assure that the output of the collection optic remains constant.