Interferometer Focus Optimization via Electronic Processor Calibration

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Solution Overview

Problem

High-density imaging formats in modern interferometry instruments exceed human visual discernment capabilities, leading to suboptimal focusing and compromised optical performance, as users often rely on visual interpretation of interference patterns to adjust focus.

Innovation Solution

An interactive or automated method to measure and correct focus settings using calibration information and electronic processors to adjust interferometer settings or mathematically propagate wavefronts, ensuring optimal focus for improved surface topography and wavefront maps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-density imaging formats are used in interferometers, then spatial resolution is improved, but visual focusing capability deteriorates

Engineering Contradiction:
Improvespatial resolutionVSAvoidvisual focusing capability
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces manual visual focusing with automated electronic processing. A processor analyzes interferometric images to calculate focus metrics and automatically adjusts focus settings, substituting the mechanical/visual focusing process with an electronic automation system that can handle high-density imaging formats beyond human visual capabilities

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

Solution Approach 2:

The interferometer system performs self-focusing through automated analysis of interferometric images. The processor evaluates focus quality metrics from the images and adjusts focus settings without requiring external visual assessment, enabling the system to optimize its own performance for high-density imaging formats

Inventive Principle:
Principle #25Self-service

2Ease of operation

If manual visual focusing is used, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improveease of operationVSAvoidoptical performance
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent implements a feedback loop where the processor continuously analyzes interferometric images to evaluate focus quality, compares it against optimal focus criteria, and automatically adjusts focus settings accordingly. This closed-loop feedback system maintains optimal focus precision while reducing the need for manual intervention

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary automated focus optimization by analyzing interferometric images and calculating optimal focus settings before final measurements are taken. This preliminary action ensures that the interferometer is properly focused for high-precision measurements without requiring manual visual adjustment

Inventive Principle:
Principle #10Preliminary action

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 optimizes the quality and resolution of surface topography and wavefront maps by ensuring the interferometer operates at best focus, enhancing measurement accuracy and precision beyond human visual limitations.

Implementation Method 1

interferometry for optical wavefront and surface topography measurements

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 2

piezo-electric transducers (PZTs)

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3542126B1Method and apparatus for optimizing the optical performance of interferometers
Publication Date: 2024.09.04 ZYGO CORP
  • EP3542126B1 patent drawingFigure 1
  • EP3542126B1 patent drawingFigure 2~3
  • EP3542126B1 patent drawingFigure 4

AI summary

A method for measuring a property of a test object with an interferometer includes: a) providing calibration information relating a focus setting for the interferometer to a position of the test object relative to a reference surface of the interferometer; b) determining the position of the test object relative to the reference surface; and c) using the interferometer to collect interferometric images of the test object for use in measuring the property of the test object.