Microscope Auto-Focus Using Displacement Sensor for Well Plates

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Solution Overview

Problem

In microscope tilting imaging, auto-focus control is hindered by varying well thicknesses and installation errors in culture vessels, leading to inefficient focusing and prolonged imaging times, especially when using well plates with multiple wells.

Innovation Solution

The microscope apparatus detects focus information while moving the stage to the scanning position and performs auto-focus control at each observation point based on this information, allowing for efficient focusing even with significant variations in well thickness and installation errors, without requiring pre-measurement during the imaging process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If auto-focus control is performed at each observation position by moving the objective lens using a piezoelectric element, then focusing accuracy is improved, but the drive range is limited and imaging time is prolonged when well thicknesses vary significantly

Engineering Contradiction:
Improvefocusing accuracyVSAvoidimaging time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent performs preliminary measurement of well bottom positions using a displacement sensor before the actual imaging process. This preliminary action allows the system to pre-calculate focus offsets for each well, so that when imaging begins, the objective lens can be quickly positioned to the correct focus position without time-consuming search movements, thus reducing imaging time while maintaining focusing accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a displacement sensor as an intermediary device to measure well bottom positions. This sensor acts as a mediator between the varying well thicknesses and the focus control system, providing precise position information that enables the main control unit to calculate appropriate focus offsets, thereby achieving accurate focusing without extending imaging time

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the objective lens is moved to compensate for varying well thicknesses and installation errors, then auto-focus control is achieved, but the limited drive range prevents appropriate focusing when position differences exceed the drive range

Engineering Contradiction:
Improveauto-focus controlVSAvoiddrive range adaptability
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent adds a vertical dimension (Z-axis) to the stage movement capability. By enabling the stage to move in the vertical direction in addition to the horizontal XY plane, the system can compensate for large variations in well bottom positions that exceed the objective lens drive range, thereby expanding the adaptability to different well configurations while maintaining auto-focus control

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Measurement precision

If pre-measurement of well thickness variation is performed separately from imaging operation, then auto-focus control accuracy is improved, but imaging time is lengthened by the additional measurement time

Engineering Contradiction:
Improveauto-focus control accuracyVSAvoidimaging time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges the focus measurement function with the imaging operation by using the same displacement sensor and control system for both purposes. The focus offset information is obtained during the imaging process itself rather than in a separate pre-measurement step, combining multiple functions into a single operational sequence and eliminating additional measurement time while maintaining focusing accuracy

Inventive Principle:
Principle #5Merging (Combining)

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 rapid and accurate auto-focus control across multiple wells, significantly reducing imaging time by integrating focus detection and adjustment into the scanning process.

Implementation Method 1

The reflected intensities from the two spots are detected and measured by one or two detectors

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

Auto-focus control performed in a microscope apparatus is performed by the movement of an objective lens using a piezoelectric element or the like

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3588162B1Microscopic device, observation method, and control program for microscopic device
Publication Date: 2022.12.21 FUJIFILM CORP
  • EP3588162B1 patent drawingFigure 1
  • EP3588162B1 patent drawingFigure 2
  • EP3588162B1 patent drawingFigure 3~4

AI summary

There are provided a microscope apparatus, an observation method, and a microscope apparatus-control program that can more efficiently perform auto-focus control and can shorten an imaging time in a case where a culture vessel is to be scanned by an image forming optical system and the auto-focus control is to be performed at each observation position. Focus information of a culture vessel (50) is detected by a first displacement sensor (18a) and a second displacement sensor (18b) while a stage (51) is moved to a scanning measurement position (P2) from an initial set position (P1), and an auto-focus control unit performs auto-focus control at every observation position on the basis of the focus information in a case where the stage (51) has been moved to the scanning measurement position (P2).