Focusing Micromirrors for High-Resolution Polychromatic Imaging

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Solution Overview

Problem

Current high-resolution microscopy and microlithography techniques face limitations in field of view, resolution, and chromatic aberration issues, particularly with polychromatic light, due to the use of high-NA microscope objectives and microlens arrays, which restrict their application and efficiency.

Innovation Solution

The use of micromirror arrays with high numerical aperture (>0.6) and achromaticity enables parallel high-resolution operations with polychromatic light, allowing for large-field imaging and micromachining by focusing light onto a sample in a confocal manner, overcoming the limitations of refractive and diffractive microlens arrays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-NA microscope objectives are used to achieve high-resolution imaging, then lateral and axial resolution are improved, but the field of view is severely limited

Engineering Contradiction:
Improvelateral and axial resolutionVSAvoidfield of view
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent divides the imaging system into multiple independent microlens elements arranged in an array, where each microlens acts as a separate imaging unit with its own high-NA objective. This segmentation allows each element to provide high-resolution imaging while the collective array covers a much larger field of view, resolving the contradiction between resolution and field size.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If microlens arrays are used to expand the field of view, then the imaging area is increased, but chromatic aberration worsens and resolution is limited

Engineering Contradiction:
Improveimaging field sizeVSAvoidresolution and chromatic performance
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent changes the material parameters of the microlens array by using achromatic lens materials and optimizing the refractive index distribution within each microlens element. This parameter optimization reduces chromatic aberration while maintaining high numerical aperture, thereby improving both resolution and color fidelity across the expanded field of view.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If stage-scanning is used to achieve wide-area imaging with simple optics, then the field of view is expanded, but imaging time increases significantly

Engineering Contradiction:
Improvefield of viewVSAvoidimaging time
Core Design Contradiction:
Area of stationary objectVSLoss of time

Solution Approach 1:

The patent segments the imaging function across multiple microlens elements that simultaneously capture different regions of the sample. This parallel acquisition approach eliminates the need for sequential stage-scanning, expanding the field of view while maintaining fast imaging speeds comparable to beam-scanning methods.

Inventive Principle:
Principle #1Segmentation

4Productivity

If beam-scanning is used to achieve fast imaging, then imaging speed is improved, but the field of view is restricted to the objective's imaging area

Engineering Contradiction:
Improveimaging speedVSAvoidfield of view
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The patent merges beam-scanning technology with a microlens array system, where the scanned beam is distributed across multiple microlens elements. This combination allows each element to contribute to the overall field of view while maintaining the fast scanning speeds of beam-scanning methods, thereby achieving both high productivity and expanded imaging area.

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 solution provides improved axial and lateral resolution, increased light collection efficiency, and the ability to operate with multiple wavelengths, enhancing the signal-to-noise ratio and enabling high-resolution imaging and micromachining beyond the diffraction limit.

Implementation Method 1

focusing micromirrors which are adapted to reflect and focus light

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 2

focusing micromirrors which are adapted to reflect and focus light

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP2389606B1High-resolution microscopy and photolithography devices using focusing micromirrors
Publication Date: 2019.08.28 ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE (EPFL)
  • EP2389606B1 patent drawingFigure 1~2
  • EP2389606B1 patent drawingFigure 3(a)~3(b)
  • EP2389606B1 patent drawingFigure 4

AI summary

The invention relates to large-field high-resolution microscopy and photolithography setups operating with polychromatic light. It includes the use of a plurality of focusing micromirrors.