Optical System Centering and MTF Measurement Integration

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Solution Overview

Problem

Existing methods for detecting the imaging quality of optical systems with multiple lenses struggle to simultaneously measure centering and imaging performance effectively, particularly in mass production, due to manufacturing and assembly tolerances that affect the alignment of optical surfaces.

Innovation Solution

A device combining an MTF measuring device for off-axis measurements and a centering measuring device, utilizing an autocollimator to determine the center of curvature, allows for simultaneous measurement and adjustment of both centering and imaging performance, optimizing the optical system's quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate measurement methods are used for centering and imaging quality, then each parameter can be measured accurately, but the measurement process becomes time-consuming and complex

Engineering Contradiction:
Improvecentering accuracyVSAvoidmeasurement efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent combines the centering measurement device and MTF measurement device into a single integrated measurement system. The centering measuring device includes an autocollimator and odometer that can simultaneously measure both the centering state of optical elements and the MTF values, eliminating the need for separate measurement processes and improving overall efficiency.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The measurement device is designed with multi-functionality to perform both centering measurement and imaging quality assessment using the same optical path and detection system. The autocollimator serves dual purposes: measuring optical axis alignment and capturing MTF characteristics, thereby reducing measurement time and complexity.

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

2Manufacturing precision

If multiple lenses are aligned precisely, then optical quality improves, but manufacturing and assembly tolerances make this difficult to achieve

Engineering Contradiction:
Improvelens alignment precisionVSAvoidassembly difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The measurement system provides real-time feedback on the centering state and optical quality of multi-lens assemblies. By measuring the actual MTF values and centering deviations during assembly, the system enables iterative adjustment and verification, ensuring that lenses are aligned within tolerances without requiring overly complex manufacturing processes.

Inventive Principle:
Principle #23Feedback

3Device complexity

If only on-axis MTF measurements are performed, then the measurement process is simple, but the imaging quality across the entire field cannot be fully characterized

Engineering Contradiction:
Improvemeasurement setup complexityVSAvoidimaging quality characterization
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent extends MTF measurements from a single on-axis point to multiple off-axis field points across the entire image field. By measuring MTF values at various field positions and combining this data with centering measurement results, the system achieves comprehensive characterization of optical quality while maintaining a relatively simple measurement setup.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 quick and efficient recording of multiple parameters, improving the imaging quality by iteratively adjusting lens positions to achieve optimal modulation transfer function values, thus enhancing the optical system's performance and centering accuracy.

Implementation Method 1

a centering measuring device (18) for measuring a centering state of the optical system, the on-axis is arranged, wherein the centering measuring device (18) comprises an autocollimator and is set up to measure a center of curvature of at least one optical surface of the optical system in reflection

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3410091B1Method for detecting a modulation transfer function and a centring system of an optical system
Publication Date: 2021.08.11 TRIOPTICS GMBH
  • EP3410091B1 patent drawingFigure 1
  • EP3410091B1 patent drawingFigure 2
  • EP3410091B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a device (2) for determining the image quality of an optical system (4) with at least one lens (6) or lens group. The device (2) comprises an MTF measuring device (10) for measuring a modulation transfer function at several field points in the image field of the optical system (4) and a centering measuring device (18) for measuring the centering state of the optical system (4). The invention further relates to a method for determining the image quality of an optical system (4) with such a device (2).