Microwave UV Lamp Power Modulation for Uniform Vertical Output

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional ultraviolet (UV) lamp systems experience high ripple in UV output and efficiency issues when operated in non-horizontal orientations, such as vertical or angled configurations, due to the migration of bulb fill and additives, leading to reduced UV output and increased bulb temperature.

Innovation Solution

A hybrid current waveform is introduced for the magnetrons in the UV lamp system, which is a combination of DC and AC, achieved by modifying the software and firmware of a switch mode power supply. This hybrid waveform includes a high percentage of DC for most of the cycle and brief interrupts, which helps maintain plasma dynamics similar to ferro-resonant supplies, improving bulb performance in non-linear orientations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If ferro-resonant power supplies are used to drive magnetrons, then the system can operate with simple hardware design, but the UV output exhibits high ripple and reduced efficiency

Engineering Contradiction:

Improvepower supply hardware designVSAvoidUV output stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent replaces the mechanical/ferro-resonant power supply system with a solid-state switching power supply system. This substitution eliminates the heavy transformers and associated ripple issues while maintaining the ability to drive magnetrons effectively, thereby resolving the contradiction between hardware simplicity and output stability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters of the power supply by using high-frequency switching components instead of traditional ferro-resonant transformers. This parameter change enables precise control of the DC voltage and current supplied to magnetrons, reducing UV output ripple while maintaining system functionality.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If solid state power supplies are used to eliminate ripple, then UV output stability improves, but bulb fill migration occurs in non-horizontal orientations

Engineering Contradiction:

ImproveUV output stabilityVSAvoidbulb fill distribution

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent introduces periodic modulation to the DC power supply to magnetrons, creating controlled plasma dynamics that counteract the effects of gravity on bulb fill. This periodic action maintains uniform bulb fill distribution even in vertical or angled orientations while preserving the low-ripple benefits of solid-state power supplies.

Inventive Principle:

Principle #19Periodic action

3Productivity

If high power magnetrons are operated at high DC voltage, then UV curing efficiency increases, but electrical energy usage increases and magnetron lifespan decreases

Engineering Contradiction:

ImproveUV curing efficiencyVSAvoidelectrical energy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent incorporates feedback control mechanisms in the solid-state power supply system to optimize the electrical energy supplied to magnetrons. By monitoring and adjusting power delivery in real-time, the system maintains high UV curing efficiency while minimizing energy consumption and reducing stress on magnetrons, thereby extending their operational lifespan.

Inventive Principle:

Principle #23Feedback

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 hybrid current waveform significantly reduces UV output ripple and maintains efficient UV emission in non-horizontal orientations, preventing color separation and improving bulb performance, while also reducing electrical energy usage and extending the lifespan of magnetrons.

Implementation Method 1

Magnetrons emit microwaves from an output antenna into a metal waveguide inside the lamp which directs the RF into a reflector cavity containing the bulb

Methodology Applied

Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

The high-frequency (e.g., 2.45GHz), high power (e.g., up to 3kW RF) electric field generated by each of the two magnetrons excites the gas inside the bulb to high energy levels, vaporizing and ionizing the mercury and additives

Methodology Applied

Scientific EffectIonization: Ionisation

Implementation Method 3

a first current signal to a first magnetron and a second current signal to a second magnetron, each current signal being modulated to provide a hybrid current profile... maintaining plasma dynamics similar to ferro-resonant supplies

Methodology Applied

Scientific EffectPlasma: Plasma

Data Source

PatentEP3704732B1Ultraviolet lamp systems and methods of operating the same

Publication Date: 2025.03.05 EXCELITAS TECHNOLOGIES CORP

Figure 1
Figure 2
Figure 3

AI summary

An ultraviolet lamp system is provided. The ultraviolet lamp system includes: (a) a bulb; (b) at least one magnetron configured to emit microwave energy configured to be received by the bulb; and (c) a power supply configured to provide electrical energy to the at least one magnetron, the power supply being adapted to modulate the electrical energy provided to the at least one magnetron such that light output from the bulb is more uniform in at least one of intensity and spectral output.