Rolling Readout Stabilizes Focus Map for Microscope Imaging

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Solution Overview

Problem

High-magnification microscope devices face challenges in acquiring accurate focus information due to small depth of field, leading to insufficient focus map accuracy when using existing image acquisition devices that either move the objective lens or use line scan cameras, resulting in incomplete or unstable focus information.

Innovation Solution

An image acquisition device with a two-dimensional image pickup element performing rolling readout, reciprocating the focal position of the objective lens in the optical axis direction while moving the field position, stabilizing focus information calculation by synchronizing pixel column exposure with focal position changes, and determining optimal reciprocation conditions to maintain focus accuracy despite sample irregularities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high magnification (20x to 40x) is used for detailed imaging, then image resolution is improved, but depth of field becomes very small causing insufficient focus coverage

Engineering Contradiction:
Improveimage resolutionVSAvoidfocus coverage
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies dynamics by making the focal position of the objective lens movable through reciprocating movement in the optical axis direction. This allows the system to dynamically adjust focus across different depths of the sample, converting a static imaging system into a dynamic one that can cover varying focal planes while maintaining high magnification resolution.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs periodic action through the reciprocating movement of the objective lens focal position. The lens moves back and forth in a periodic manner along the optical axis, systematically scanning through different focal depths. This periodic scanning ensures comprehensive coverage of the sample's depth range while maintaining consistent imaging quality.

Inventive Principle:
Principle #19Periodic action

2Area of stationary object

If the field position of the objective lens is moved to cover a wide area of the sample, then coverage area is improved, but imaging time increases significantly

Engineering Contradiction:
Improvecoverage areaVSAvoidimaging time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The patent implements continuity of useful action by performing reciprocating movement of the focal position simultaneously with field position movement. Instead of sequentially moving field position then adjusting focus, both actions occur continuously and concurrently, eliminating idle time and maintaining productive imaging action throughout the scanning process.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent applies preliminary action by pre-planning and executing coordinated movement of both focal position and field position. The reciprocating focal position movement is synchronized with field position changes in advance, ensuring that focus adjustment is already in progress or complete by the time the field position moves to the next region, thereby minimizing total imaging time.

Inventive Principle:
Principle #10Preliminary action

3Area of stationary object

If light is input to first and last pixel columns from different positions on the sample, then rolling readout coverage is improved, but focus information accuracy deteriorates

Engineering Contradiction:
Improvereadout coverageVSAvoidfocus information accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent applies local quality by ensuring that each pixel column receives light from a consistent, localized position on the sample during reciprocating focal position movement. This localized consistency in light input path for each pixel column maintains uniform focus conditions across the readout, improving focus information accuracy while preserving the rolling readout coverage advantage.

Inventive Principle:
Principle #3Local quality

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 production of focus maps by stabilizing focus information calculation and ensuring accurate focus map generation, even with irregular sample surfaces and warpage, by synchronizing pixel column exposure with focal position changes and optimizing reciprocation conditions.

Implementation Method 1

an image pickup element (6) for acquiring image data of the sample (S)

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP2990849B1Image acquisition device and method and system for creating focus map for specimen
Publication Date: 2020.09.02 HAMAMATSU PHOTONICS KK
  • EP2990849B1 patent drawingFigure 1
  • EP2990849B1 patent drawingFigure 2(a)~2(b)
  • EP2990849B1 patent drawingFigure 3

AI summary

An image acquisition device 1 reciprocates a focal position of an objective lens 25 with respect to a sample S in the optical axis direction of the objective lens 25, while moving a field position V of the objective lens 25 with respect to the sample S. This makes it possible to acquire contrast information of image data at the field position V of the objective lens 25 sequentially as the field position V moves with respect to the sample S. The image acquisition device 1 acquires the image data by the rolling readout of the image pickup element 6 according to the reciprocation of the focal position of the objective lens 25. This stabilizes the number of pieces of focus information calculated for each scan of the focal position of the objective lens 25. Therefore, the focus map can be produced rapidly and accurately.