Dual-Sensor Optical Inspection With Holder-Based Alignment Reference

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Solution Overview

Problem

Existing optical inspection methods for flat test objects suffer from reduced measurement accuracy due to the need for repositioning the object to capture both sides, which is time-consuming and introduces alignment errors.

Innovation Solution

An optical testing device with a holder designed as a test standard, allowing simultaneous detection of both sides of the test object using two optical sensors, eliminating the need for repositioning and incorporating the holder's geometry as a reference for alignment correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the test object is repositioned to capture both sides, then measurement completeness is improved, but measurement time increases and accuracy decreases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The holder is designed as a test standard with known geometry that is simultaneously measured by both optical sensors. This merging of the holder and test object into a single measurement process allows both sides to be captured without repositioning, resolving the contradiction between measurement completeness and measurement time.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The holder acts as an intermediary reference structure that bridges the two optical sensors. By measuring the holder's known geometry, the system can align and correlate measurements from both sensors, enabling accurate simultaneous measurement of both sides without repositioning the test object.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the test object is repositioned to capture both sides, then measurement completeness is improved, but alignment errors increase

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidalignment accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The holder is pre-designed with a precisely known geometry that serves as a reference standard. This preliminary preparation of the holder's geometry allows for accurate alignment and correlation of measurements from both optical sensors without requiring repositioning or complex alignment procedures during measurement.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The holder serves as an intermediary reference that mediates between the two optical sensors. By measuring the holder's known geometry, the system can compensate for and align sensor readings, eliminating alignment errors that would otherwise occur during repositioning operations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If a complex alignment procedure is used, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidalignment complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The holder is designed to be self-aligning through its known geometry. The optical sensors automatically use the holder's geometric features as references to establish their relative positions and orientations, eliminating the need for complex external alignment procedures or adjustments during measurement.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The holder's geometry is pre-defined and known before measurement. This preliminary specification of the holder's geometry serves as a built-in alignment reference, allowing the system to automatically correlate sensor measurements without requiring complex alignment operations or additional alignment hardware.

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

Enhances measurement accuracy and speed by eliminating the need for repositioning, reducing measurement uncertainties, and enabling fast, reliable testing of flat test objects with high precision.

Implementation Method 1

two optical sensors (8, 10) for detecting the three-dimensional surface topography of the test object (6)

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4325166B1Optical inspection apparatus
Publication Date: 2026.02.04 JENOPTIK IND METROLOGY GERMANY
  • EP4325166B1 patent drawingFigure 1~2
  • EP4325166B1 patent drawingFigure 3~4

AI summary

An optical inspection device 2 for inspecting flat test objects 6 comprises a holder 4 for the test object 6 and two optical sensors 8, 10 for detecting the three-dimensional surface topography of the test object 6. According to the invention, the holder 4 is designed at least partially as a test standard and is arranged relative to the sensors 8, 10 such that the sensors 8, 10 probe the test object 4 from opposite sides and, when detecting the test object 6, also detect the holder 4 as a test standard, at least partially.