Micromanipulator Collision-Free Positioning via Tolerance-Aware Z-Height Calculation

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Solution Overview

Problem

Current methods for micromanipulation, such as microinjection and single cell removal, face challenges in achieving precise and collision-free positioning of micromanipulation tools relative to sample carriers, particularly due to mechanical and procedural limitations, including inaccuracies in determining the Z-direction position and tolerances, leading to potential tool damage and inefficiencies in cell isolation.

Innovation Solution

A method that determines the focal positions of both the sample carrier and the micromanipulation tool using microscope objectives with varying numerical apertures, calculates a lowering distance accounting for tolerance profiles, and iteratively refines the positioning to ensure accurate and collision-free movement, allowing for fully automatic and precise manipulation across the sample surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the micromanipulation tool is lowered based on calculated descent path without tolerance correction, then positioning speed is improved, but collision with sample carrier occurs causing tool damage

Engineering Contradiction:
Improvepositioning speedVSAvoidtool integrity
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by calculating a safety distance based on tolerance profiles before lowering the micromanipulation tool. The control system determines the actual position of both the tool tip and sample carrier surface, calculates the descent path subtracting a safety distance derived from tolerance values, and lowers the tool only to this corrected position. This prevents collision by anticipating potential position deviations within the tolerance range, maintaining both positioning speed and tool integrity.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Device complexity

If manual calibration methods are used without precise handling tools, then system complexity is reduced, but positioning precision deteriorates requiring highly experienced users

Engineering Contradiction:
Improvesystem complexityVSAvoidpositioning precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements self-service by enabling the system to automatically determine its own positioning parameters. The control system autonomously calculates the actual position of the micromanipulation tool tip and sample carrier surface using microscope images, determines tolerance profiles, computes the corrected descent path, and executes the positioning without requiring manual calibration by experienced users. This automation maintains high positioning precision while reducing the operational skill barrier.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If additional measuring instruments are added to determine Z-direction position, then positioning precision is improved, but device complexity increases

Engineering Contradiction:
ImproveZ-direction positioning precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies universality by making the existing microscope objective serve multiple functions. Instead of adding separate measuring instruments, the system uses the microscope objective both for observing the sample and for determining the actual positions of the tool tip and sample carrier surface in the Z-direction. The dual use of the microscope's imaging capability for both observation and measurement achieves high positioning precision without increasing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Loss of time

If objective lens imaging tolerances are not considered, then calibration time is reduced, but tool damage occurs due to collision

Engineering Contradiction:
Improvecalibration timeVSAvoidtool damage
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-calculating the tolerance profile of the objective lens and incorporating it into the descent path calculation before lowering the tool. The control system determines the tolerance values characterizing the objective lens's imaging inaccuracies, uses these to calculate a safety distance, and subtracts this from the nominal descent path. This preliminary consideration of imaging tolerances prevents tool damage while maintaining efficient calibration timing.

Inventive Principle:
Principle #10Preliminary action

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

This approach enables precise and damage-free positioning of micromanipulation tools over the entire sample surface, reducing calibration time, improving system reliability, user-friendliness, and positional accuracy, while preventing collisions between the tool and sample carrier.

Implementation Method 1

focusing a first microscope objective with a first numerical aperture NA1 to at least one point P on the surface of the sample carrier to determine a focal position ZP of at least one point P

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP2558900B1Method for collision-free positioning of a micromanipulation tool
Publication Date: 2023.07.19 MMI AG
  • EP2558900B1 patent drawingFigure 1a~1b
  • EP2558900B1 patent drawingFigure 2
  • EP2558900B1 patent drawingFigure 3

AI summary

The invention relates to a method for the collision-free positioning of a micromanipulator tool relative to a sample carrier with the aid of a microscope, comprising the following steps: a) determining the focal position ZP of at least one point P on the surface of the sample carrier by focusing a microscope objective having a first numerical aperture NA1 on the at least one point; b) positioning the micromanipulator tool on the optical axis of the microscope; c) determining the focal position ZM of the micromanipulator tool by focusing the microscope objective or a second microscope objective having a second numerical aperture NA2 smaller than the first numerical aperture NA1 on the tip of the micromanipulator tool; d) calculating the lowering travel ZA(P) while taking a predetermined tolerance profile ?Z into account, by means of the following equation: ZA(P) = ZM - ZP - ?Z, where ?Z = ?ZM +?ZP, wherein ?ZM and ?ZP is a predetermined tolerance in determining the position of the manipulator tool and of the sample carrier, respectively; and e) positioning the micro manipulator tool at the point P by lowering by the lowering travel ZA(P).