Charged Particle Beam Light Condensing Unit
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Solution Overview
Problem
Existing charged particle beam devices under low vacuum conditions suffer from reduced light yield due to isotropic emission of light from collisions between secondary electrons and gas molecules, with only a portion of this light being detected by the photodetector, leading to deactivated light and deteriorated image quality.
Innovation Solution
Incorporation of a light condensing unit between the sample and photodetector, utilizing materials with high diffuse reflectance to condense and redirect previously deactivated light onto the photodetector, thereby improving the yield of detected light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light is generated isotropically by collision between secondary electrons and gas molecules, then light is emitted in all directions, but most light is emitted away from the photodetector and is deactivated
Solution Approach 1:
A light condensing unit is introduced as an intermediary component between the light emission region and the photodetector. This unit includes a light guide and a light condensing lens that work together to collect and redirect light that would otherwise be lost, channeling it toward the photodetector to improve detection efficiency
Solution Approach 2:
The light condensing unit transforms the isotropic light emission (3D spherical distribution) into a directional beam by using optical elements positioned at specific dimensions and angles. The light guide collects light from multiple directions and the condensing lens focuses it onto the photodetector, effectively converting spatial distribution to improve light capture
2Illumination intensity
If a light condensing unit is added to improve light yield, then more light is detected, but device complexity increases
Solution Approach 1:
The light condensing unit combines multiple optical functions into a single integrated structure. The light guide and light condensing lens are positioned and configured to work together as a unified optical system, reducing the need for separate components and simplifying the overall device architecture while maintaining improved light detection capability
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 light condensing unit enhances the yield of light detected by the photodetector, improving image quality by capturing and redirecting previously lost light, specifically utilizing fluorine-based resins for optimal diffuse reflectance in the visible ultraviolet range.
Implementation Method 1
utilizing materials with high diffuse reflectance to condense and redirect previously deactivated light onto the photodetector
Implementation Method 2
a positive electrode configured to form an electric field that accelerates a secondary electron emitted from the sample
Implementation Method 3
a photodetector configured to detect light generated by a collision between the accelerated secondary electron and the gas molecule
Data Source
AI summary
In order to improve a yield of light generated by a collision between secondary electrons and gas molecules, the invention provides a charged particle beam device including: a charged particle beam source configured to irradiate a sample with a charged particle beam; a sample chamber configured to hold the sample and a gas molecule; a positive electrode configured to form an electric field that accelerates a secondary electron emitted from the sample; a photodetector configured to detect light generated by a collision between the accelerated secondary electron and the gas molecule; and a light condensing unit disposed between the sample and the photodetector, having a light emitting space in which the light is generated, and configured to condense the light generated in the light emitting space on a photodetector side.