Phase Contrast Microscope Meniscus Refraction Correction

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Solution Overview

Problem

Existing phase-contrast microscopes face challenges in accurately recognizing and adjusting for the varying shape of a meniscus formed on the liquid surface in culture vessels, especially during time-lapse imaging, due to changes in liquid level caused by evaporation, which affects the clarity of phase contrast images.

Innovation Solution

A phase-contrast microscope system that includes a liquid-surface-measurement illumination unit, a transmitted light detection unit, a focal plane changing mechanism, and an adjustable optical system to estimate and adjust for the liquid surface shape, allowing precise correction of refraction effects caused by the meniscus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional phase-contrast microscope is used to observe cells in culture liquid, then phase contrast measurement can be performed, but the meniscus effect causes optical axis displacement and prevents clear image acquisition

Engineering Contradiction:
Improvephase contrast measurement accuracyVSAvoidmeniscus refraction effect
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical adjustment methods with optical field-based correction. By using a spatial light modulator to generate conjugate phase distributions that match the meniscus shape, the system corrects refraction effects through optical field manipulation rather than mechanical realignment, thereby improving phase contrast measurement accuracy while eliminating meniscus interference

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent dynamically adjusts the phase distribution parameters of the illumination light to match the changing meniscus shape. By modifying the phase conjugate distribution in real-time based on detected meniscus characteristics, the system compensates for refraction effects and maintains optimal phase contrast measurement conditions despite variations in culture liquid level

Inventive Principle:
Principle #35Parameter changes

2Productivity

If time-lapse imaging is performed to observe cell changes over time, then dynamic cell behavior can be captured, but liquid evaporation causes meniscus shape changes that degrade image quality

Engineering Contradiction:
Improvetime-lapse imaging capabilityVSAvoidimage quality consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the meniscus detection unit continuously monitors meniscus shape changes during time-lapse imaging, and the spatial light modulator dynamically adjusts the phase conjugate distribution in response to detected changes. This closed-loop control maintains consistent image quality throughout the time-lapse sequence despite liquid evaporation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transitions from static optical alignment to dynamic adaptation by continuously adjusting the phase conjugate distribution to match changing meniscus conditions. The system's ability to adapt in real-time ensures reliable image quality consistency throughout extended time-lapse observation periods

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the optical system is adjusted to compensate for meniscus effects, then image quality improves, but the complexity of the optical system increases

Engineering Contradiction:
Improveimage clarityVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions into the existing optical path by using the spatial light modulator to simultaneously perform phase conjugation for meniscus correction and maintain normal phase contrast illumination. This multi-functional approach improves image clarity without requiring separate dedicated correction optical paths, thereby limiting the increase in system complexity

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

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 accurate recognition and adjustment for the meniscus shape, resulting in high-precision removal of refraction effects and improved phase contrast imaging by adjusting the optical characteristics based on real-time liquid surface shape measurements.

Implementation Method 1

a meniscus is formed on the liquid surface of the culture liquid due to the effect of surface tension of the culture liquid. The meniscus acts as a lens and shifts the optical axis of ring-shaped illumination light, thereby exerting an effect on direct light and refracted light that enter the phase plate

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

an adjustment optical system whose optical characteristics are adjustable and that adjusts refraction of the phase-contrast-measurement illumination light due to the liquid surface shape of the liquid in the vessel in accordance with the optical characteristics

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP3318912B1Phase contrast microscope and imaging method
Publication Date: 2020.07.01 FUJIFILM CORP
  • EP3318912B1 patent drawingFigure 1
  • EP3318912B1 patent drawingFigure 2~4
  • EP3318912B1 patent drawingFigure 5~6

AI summary

A liquid surface in a culture vessel is irradiated with liquid-surface-measurement illumination light, and transmitted light that has passed through the liquidis detected by an imaging unit. A relative positional relationship between a focal plane of an image forming optical system and the culture vessel is changed, a detection signal for each position of the focal plane is obtained, and a liquid surface shape is estimated on the basis of the detection signal for each position of the focal plane. Then, on the basis of the estimated liquid surface shape, adjustment information for adjusting the optical characteristics of an adjustment optical system for adjusting refraction of light due to the liquid surface shape is acquired. After the optical characteristics of the adjustment optical system have been adjusted on the basis of the adjustment information, an image of a specimen is captured by irradiating the culture vessel with phase-contrast-measurement illumination light.