Pipette Tip Leading End Detection Using Pressure Change Thresholds
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Solution Overview
Problem
Existing pipette tip detection methods fail to accurately determine the leading end position due to noise interference in pressure signals, leading to erroneous detection and potential contamination or damage to the reference surface.
Innovation Solution
A pipette tip leading end detection device and program that calculates a determination value based on the speed of pressure change using multiple AD conversion values, setting a threshold value higher than the maximum noise level to accurately detect the pipette tip's proximity to the reference surface without contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the leading end of the pipette tip is contacted to the reference surface for position detection, then the detection accuracy is improved, but the reference surface may be damaged or contaminated
Solution Approach 1:
The patent applies preliminary anti-action by using air pressure detection to anticipate the contact between the pipette tip leading end and the reference surface before actual contact occurs. The system detects pressure changes in the air passage that indicate proximity to the reference surface, allowing the pipette nozzle to stop lowering before contact happens, thus preventing damage or contamination while still achieving accurate position detection.
2Object-affected harmful factors
If air pressure detection is used to detect proximity without contact, then the reference surface is protected, but detection accuracy is reduced due to noise in pressure signals
Solution Approach 1:
The patent implements feedback by continuously monitoring air pressure changes and using this information to control the lowering of the pipette nozzle. The system measures pressure at multiple positions during lowering, compares the pressure change rate to a threshold value, and adjusts the lowering operation accordingly. This feedback mechanism allows the system to distinguish true proximity signals from noise, maintaining detection accuracy while protecting the reference surface.
3Measurement precision
If the pipette nozzle is lowered slowly to improve detection accuracy, then the position can be determined more precisely, but the processing time increases
Solution Approach 1:
The patent applies dynamics by adjusting the lowering speed of the pipette nozzle based on the detected pressure change rate. When the leading end of the pipette tip approaches the reference surface (indicated by a pressure change rate exceeding the threshold), the system automatically slows down or stops the lowering operation. This dynamic adjustment allows for precise detection near the reference surface while maintaining faster operation at greater distances, optimizing both accuracy and processing 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
Enables precise detection of the pipette tip's position close to the reference surface, preventing contamination and damage, and ensuring accurate liquid removal by minimizing noise impact, thus stabilizing the detection process.
Implementation Method 1
detects a pressure change that occurs when the leading end of the pipette tip approaches a predetermined reference part
Data Source
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AI summary
The present invention addresses the problem of providing a device for detecting the leading end of a pipette tip which is capable of detecting, with excellent accuracy, a state in which the leading end of the pipette tip is in a position close to but not in contact with a reference surface. An AD conversion value of the pressure between a pipette tip 31 and a pump 33 detected by a pressure sensor 36, while a pipette nozzle 32 is being lowered towards a bottom surface 22 of an accommodation part 21 and air is being discharged from the leading end 311 of the pipette tip by the pump, is used to obtain a determination value. If the determination value is equal to or greater than a preset threshold value, it is detected that the leading end 311 of the pipette tip 31 is close to but not in contact with the bottom surface 22 of the accommodation part 21, i.e. a reference surface. The threshold value is set to a value greater than the maximum value of noise included in the determination value which occurs in the course of moving the leading end 311 of the pipette tip 31 towards the bottom surface 22 of the accommodation part 21.