Aberration-Correcting Optical Unit for Laser Microscopes

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Solution Overview

Problem

Current aberration correction methods for microscopes, such as the correction ring and wave front conversion elements, are cumbersome, require manual adjustment, and can lead to decreased image quality due to polarization mismatch and complexity in existing optical systems.

Innovation Solution

An aberration correction optical unit using liquid crystal elements and a variable waveplate, which can be integrated into existing microscopes to automatically correct wave front aberrations by controlling the phase modulation amount based on observation mode and specimen conditions, without the need for manual adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a correction ring is used to adjust the objective lens position, then the imaging performance can be optimized for different cover glass thicknesses, but the adjustment process becomes cumbersome and time-consuming

Engineering Contradiction:
Improveimaging performanceVSAvoidadjustment process
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical correction ring adjustment system with an optical aberration correction system. Instead of manually rotating a correction ring to physically adjust lens positions, the system uses a spatial light modulation element (such as a liquid crystal device) that can be electrically controlled to introduce compensating wavefront aberrations. This substitution transforms a mechanical adjustment process into an electrical control process, enabling automated and precise aberration correction without manual intervention.

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

Solution Approach 2:

The patent implements a system where the microscope automatically measures and corrects aberrations without requiring manual operation. The control unit automatically controls the spatial light modulation element based on measured aberration data, enabling the system to self-correct imaging aberrations. This eliminates the need for operators to manually adjust correction rings and perform repeated focusing adjustments.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If manual adjustment of correction ring and focusing is performed repeatedly, then optimal imaging position can be achieved, but the process takes excessive time and causes fluorescent pigment fading

Engineering Contradiction:
Improveoptimal imaging positionVSAvoidadjustment time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent implements a feedback mechanism where aberration information is measured (either through wavefront sensing or by analyzing out-of-focus image information) and this measurement is fed back to the control unit. The control unit then automatically adjusts the spatial light modulation element to compensate for the measured aberrations. This closed-loop feedback system eliminates the need for repeated manual trial-and-adjustment cycles, achieving optimal imaging position rapidly and automatically.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent performs preliminary aberration measurement and correction before image acquisition begins. By measuring the wavefront aberration or analyzing out-of-focus information in advance and pre-adjusting the spatial light modulation element, the system prepares the optimal imaging condition beforehand. This preliminary action eliminates the need for time-consuming repeated adjustments during the imaging process.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If wave front conversion elements are used for aberration correction, then imaging performance can be improved, but the optical system becomes more complex and requires additional relay optical systems

Engineering Contradiction:
Improveimaging performanceVSAvoidoptical system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent designs the spatial light modulation element to serve multiple functions within a single component. The same device not only corrects aberrations but also can be positioned at different locations in the optical path (such as at the pupil plane or in the image plane) to address different types of aberrations. This multi-functional design eliminates the need for separate correction rings, wavefront conversion elements, and relay optical systems, thereby reducing overall system complexity while maintaining comprehensive aberration correction capability.

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

4Manufacturing precision

If polarization-maintaining optical elements are used, then aberration correction can be achieved, but the optical system complexity increases due to polarization matching requirements

Engineering Contradiction:
Improveaberration correctionVSAvoidpolarization control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a variable waveplate with controllable retardation that can dynamically adjust its optical parameters. By changing the retardation value, the system can adapt to different polarization states of incident light and fluorescence without requiring fixed polarization-maintaining elements. This parameter change capability allows the system to maintain aberration correction effectiveness across various polarization conditions while reducing the need for complex polarization control mechanisms.

Inventive Principle:
Principle #35Parameter changes

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 solution enables precise and automatic aberration correction, enhancing image resolution and reducing the complexity of the optical system, while optimizing the polarization characteristics for both incident light and fluorescence, thereby improving imaging performance across various observation modes.

Implementation Method 1

a first phase modulation element (3a), a variable waveplate (3b), and a second phase modulation element (3c) which are disposed in this order from a light source side along an optical axis... each of the first phase modulation element (3a), the variable waveplate (3b), and the second phase modulation element (3c) is a liquid crystal element

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 2

a variable waveplate (3b)... capable of changing a polarization state of the light flux by controlling a phase difference between two linearly polarized lights orthogonal to each other

Methodology Applied
Scientific EffectBirefringence: Birefringence

Data Source

PatentEP2887132B1Aberration-correcting optical unit and laser microscope
Publication Date: 2019.10.02 CITIZEN WATCH CO LTD
  • EP2887132B1 patent drawingFigure 1
  • EP2887132B1 patent drawingFigure 2A~2B
  • EP2887132B1 patent drawingFigure 3

AI summary

An aberration correction optical unit (3) disposed in an optical system includes: a first phase modulation element (3a) and a second phase modulation element (3c) each having a polarization characteristic; and a variable waveplate (3b) disposed between the first and second phase modulation elements so that an optical axis of the variable waveplate has a predetermined angle with respect to optical axes of the two phase modulation elements, in order to correct an aberration generated by the optical system.