Capacitance Proximity Sensing for Collision Avoidance in Electron Microscopes

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Solution Overview

Problem

Particle beam instruments, such as electron microscopes, face challenges in preventing collisions between moveable components, particularly the sensitive EBSD camera system, which can result in costly damage due to the lack of effective collision detection and prevention mechanisms.

Innovation Solution

A system utilizing capacitance sensors to monitor the capacitance between components and output a proximity alert signal when the distance between them reaches a critical threshold, allowing for the prediction and prevention of collisions by adjusting the movement of components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a touch alarm system is used to detect collisions, then collision detection capability is provided, but damage prevention is insufficient due to latency and continued movement after contact

Engineering Contradiction:
Improvecollision detection capabilityVSAvoiddamage to sensitive components
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The capacitance sensor detects changes in capacitance that occur before physical contact between components, allowing the system to take preliminary action by halting movement before the collision actually occurs. This eliminates the latency problem of touch alarms by detecting the impending collision rather than the contact itself.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies a counter-action by stopping component movement in response to capacitance changes that indicate an approaching collision. This preliminary anti-action prevents the harmful effect of collision damage before it can occur, rather than merely reacting after contact is made.

Inventive Principle:
Principle #9Preliminary anti-action

2Measurement precision

If moveable components are positioned close to the specimen for improved detection, then detection sensitivity is enhanced, but collision risk increases

Engineering Contradiction:
Improvedetection sensitivityVSAvoidcollision risk
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The capacitance sensor provides continuous feedback on the position and proximity of moveable components relative to the specimen and other components. This feedback enables real-time monitoring and automatic adjustment of component positions to maintain optimal detection sensitivity while preventing collisions through early warning signals.

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 system effectively predicts imminent collisions, enabling the avoidance of damage by halting or altering the movement of components, thereby reducing the risk of costly repairs and downtime in electron microscopes and other particle beam instruments.

Implementation Method 1

capacitance sensors to monitor the capacitance between components and output a proximity alert signal when the distance between them reaches a critical threshold

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3665470B1Collision avoidance for particle beam instruments
Publication Date: 2023.11.29 OXFORD INSTR NANOTECHNOLOGY TOOLS LTD
  • EP3665470B1 patent drawingFigure 1
  • EP3665470B1 patent drawingFigure 2
  • EP3665470B1 patent drawingFigure 3~4

AI summary

A system for preventing collisions between components in a particle beam instrument is disclosed. The system is particularly beneficial in use with instruments wherein moveable components are used within a chamber that obscures them from being viewed from outside the chamber. The system comprises: a capacitance sensor configured to monitor the capacitance between a first component and a second component of the instrument, and a proximity module configured to: derive a capacitance parameter from the monitored capacitance between the first component and the second component; and output a proximity alert signal in accordance with a comparison between the derived capacitance parameter and a predetermined capacitance parameter threshold value.