Passively Cooled LED Light Engine for Photocuring

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Solution Overview

Problem

Current photocuring systems, such as those using QTH, arc lamps, and LEDs, face challenges with heat management, spectral stability, and compatibility with various photoinitiators, leading to inefficient polymerization and high maintenance costs.

Innovation Solution

A compact, passively cooled LED light engine system that provides stable, intense light across a broad spectrum suitable for photocuring, with independently operable LED modules and optimized thermal management to reduce heat output and enhance spectral purity and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If QTH or arc lamps are used to provide light for photocuring, then broad emission spectra suitable for initiating polymerization in a broad range of resins is achieved, but substantial thermal management systems are required and lamp lifespan is reduced

Engineering Contradiction:
Improvespectral compatibilityVSAvoidheat output
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

The invention divides the single broad-spectrum lamp into multiple separate LED modules, each emitting at a specific wavelength. This segmentation allows each module to target specific photoinitiators without generating excessive heat, while collectively covering a broad spectral range for universal compatibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the fundamental operating parameters from single broad-spectrum high-temperature sources to multiple narrow-band low-temperature LED sources. By operating at lower temperatures and using multiple discrete wavelength sources, the system achieves both spectral versatility and reduced thermal management requirements.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If QTH or arc lamps are used to provide light for photocuring, then broad emission spectra suitable for initiating polymerization in a broad range of resins is achieved, but costly replacement parts are required due to reduced lifespan

Engineering Contradiction:
Improvespectral compatibilityVSAvoidlamp lifespan
Core Design Contradiction:
Adaptability or versatilityVSDuration of action of stationary object

Solution Approach 1:

The system uses multiple independent LED modules instead of a single lamp. Each module can be independently replaced if needed, and LEDs generally have longer operational lifespans than traditional lamps, reducing maintenance costs and improving system reliability.

Inventive Principle:
Principle #1Segmentation

3Power

If QTH or arc lamps are used to provide light for photocuring, then sufficient light output is achieved, but significant warm-up periods are required before spectral output is stable

Engineering Contradiction:
Improvelight outputVSAvoidwarm-up period
Core Design Contradiction:
PowerVSLoss of time

Solution Approach 1:

The invention replaces the thermal-mechanical lamp heating system with solid-state LED modules that achieve full spectral output immediately upon activation. This substitution eliminates the warm-up period entirely while maintaining sufficient light output for photocuring applications.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Temperature

If LEDs are used to provide light for photocuring, then much less heat is generated relative to arc and QTH lamps, but broad emission spectrum and poor spectral stability remain issues

Engineering Contradiction:
Improveheat outputVSAvoidspectral stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

By segmenting the light source into multiple LED modules with fixed, narrow emission bands, the system achieves spectral stability within each module. The collective output covers a broad range while maintaining stable, predictable emission characteristics from each individual module.

Inventive Principle:
Principle #1Segmentation

5Ease of operation

If optics are used to narrow the emission band and focus the light output from LEDs, then directional light is achieved, but loss in power and increase in thermal output occur

Engineering Contradiction:
Improvelight directionalityVSAvoidpower loss
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

Each LED module is designed with its own optical elements optimized for its specific wavelength and emission pattern. This localized optimization allows each module to deliver light efficiently in the desired direction without significant power loss, and the modules can be positioned to achieve the overall directional illumination pattern.

Inventive Principle:
Principle #3Local quality

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 LED light engine system offers superior performance and cost-effectiveness by providing consistent, high-intensity light for photocuring, with extended lifespan and reduced maintenance, ensuring uniform polymerization across a wide range of photoinitiators and environments.

Implementation Method 1

The present invention provides a solid state light source for use in photocuring applications

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 2

The photoinitiator enters an excited state upon absorption of photons of the correct wavelength inducing the creation of free-radicals. The free-radicals induce curing, hardening, and/or polymerization of monomeric, oligomeric or polymeric resin/adhesive

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 3

each metal base providing a heat conducting path between a solid state light source and the metal platform whereby heat generated by the solid state light source is conducted via the base to the platform

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

the housing is vented to allow air flow through the second volume to provide passive convective cooling of the platform

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2861342B1Solid state light source for photocuring
Publication Date: 2021.02.17 LUMENCOR INC
  • EP2861342B1 patent drawingFigure 1A~1B
  • EP2861342B1 patent drawingFigure 2A~2B
  • EP2861342B1 patent drawingFigure 2C

AI summary

A compact passively-cooled solid state illumination system is provided as a replacement for conventional arc light, metal halide and Xenon white-light sources for photocuring applications. The solid state illumination system utilizes LED modules to generate high intensity light output suitable for photocuring. The light output is continuous in the visible spectrum from 380nm to 530nm and is suitable for photocuring using a wide range of photoinitiators. A touchscreen interface allows programming of spectral output, intensity and duration. Output can be initiated using the touchscreen interface and/or a foot pedal.