Electrodeless Plasma Light Source for Uniform UV Illumination
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Solution Overview
Problem
Existing high-brightness light sources, such as arc lamps, face issues with electrode wear and contaminant particle generation, particularly in ultraviolet spectrum applications, where they fail to provide satisfactory brightness and uniformity.
Innovation Solution
A plasma light source is developed using a pulse laser generator and a continuous wave (CW) laser generator to ignite and maintain plasma, with dichroic mirrors and reflective structures like elliptical and spherical mirrors to concentrate and homogenize the plasma light, eliminating the need for electrodes and enhancing brightness and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If arc lamps with electrodes are used to generate high-brightness light, then light output is achieved, but electrode wear and contaminant particle generation occur
Solution Approach 1:
The patent removes electrodes from the light generation system entirely. Instead of using electrode-based arc discharge, the invention employs a cathodeless plasma light source where plasma is generated and sustained by electromagnetic field coupling between a coil and the plasma medium, thereby eliminating the source of contaminant particles while maintaining high-brightness light output
Solution Approach 2:
The patent replaces the mechanical electrode contact system with an electromagnetic field-based plasma generation system. The coil generates a time-varying magnetic field that induces electric fields to sustain plasma without physical contact, substituting mechanical electrode wear with non-contact electromagnetic energy transfer
2Illumination intensity
If arc lamps are used for ultraviolet spectrum applications, then light generation is achieved, but satisfactory brightness and uniformity are not provided
Solution Approach 1:
The patent employs a reflective cavity with specifically designed geometry and reflective coating to uniformly distribute and redirect ultraviolet plasma light. The cavity structure ensures that light from different plasma regions is reflected and combined to produce uniform illumination, addressing the non-uniformity issue while enhancing overall UV brightness
Solution Approach 2:
The plasma light source is designed to generate broadband spectrum including ultraviolet, visible, and infrared regions simultaneously. The system can provide high-brightness output across multiple spectral ranges, making it universally applicable for various inspection and manufacturing applications that require different wavelength ranges
3Reliability
If electrodes are used in plasma light sources, then plasma ignition is achieved, but electrode degradation occurs over time
Solution Approach 1:
The patent introduces a coil as an intermediary element that generates electromagnetic fields to ignite and sustain plasma without direct material contact. The coil acts as a mediator between the power source and plasma, enabling reliable plasma ignition while avoiding the degradation issues associated with electrode-material interactions
Solution Approach 2:
The plasma medium itself serves as the working substance that is continuously regenerated. The system maintains plasma through electromagnetic coupling where the plasma's own conductivity and the coil's magnetic field work together to sustain the discharge, eliminating the need for consumable electrodes that degrade over time
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 plasma light source provides high-brightness, uniform plasma light without electrode degradation, improving performance in semiconductor manufacturing and inspection processes, particularly in ultraviolet spectrum applications.
Implementation Method 1
a pulse laser generator configured to generate a pulse laser beam
Implementation Method 2
a chamber configured to receive the pulse laser beam to ignite plasma
Implementation Method 3
a continuous wave (CW) laser generator configured to generate an infrared ray (IR) CW laser beam
Implementation Method 4
the IR CW laser beam to maintain the plasma in an ignited state
Implementation Method 5
a first dichroic mirror configured to transmit or reflect the pulse laser beam and reflect or transmit the IR CW laser beam
Implementation Method 6
an elliptical mirror and is disposed at a focus of the elliptical mirror, and the pulse laser beam and the IR CW laser beam are concentrated on the chamber by the elliptical mirror
Implementation Method 7
the pulse laser beam and the IR CW laser beam are concentrated on the chamber by the elliptical mirror
Implementation Method 8
discharge plasma light generated by the plasma
Implementation Method 9
particularly in ultraviolet spectrum applications
Data Source
AI summary
Provided are a plasma light source capable of solving a problem occurring when an arc discharge lamp is used and an inspection apparatus capable of providing uniform and high-brightness plasma light. The plasma light source includes a pulse laser generator configured to generate a pulse laser beam, a continuous wave (CW) laser generator configured to generate an infrared ray (IR) CW laser beam, a first dichroic mirror configured to transmit or reflect the pulse laser beam and reflect or transmit the IR CW laser beam, a chamber configured to receive the pulse laser beam to ignite plasma and the IR CW laser beam to maintain the plasma in an ignited state, and discharge plasma light generated by the plasma, and a second dichroic mirror configured to transmit the pulse laser beam and the IR CW laser beam and reflect the plasma light.