Cubic Element Position Measurement with Adaptive Illumination

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Solution Overview

Problem

Existing position measuring systems for cubic objects like LED elements on substrates fail to account for fluctuations in the positional relationship between the imaging device and the substrate during imaging, leading to variations in measured positions due to changes in light direction and shading.

Innovation Solution

A position measuring system that includes an imaging device, illumination device, image processing unit, and illumination condition specifying unit to determine a preferred illumination condition that minimizes fluctuations in measured positions by adjusting light conditions based on the positional relationship between the imaging device and the substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If imaging is performed while transporting the substrate by conveyor, then productivity is improved, but measurement precision deteriorates due to positional relationship fluctuations

Engineering Contradiction:
Improvesubstrate inspection efficiencyVSAvoidposition measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The illumination device changes illumination parameters (light emission direction, illumination angle) to adapt to fluctuations in the positional relationship between the imaging device and substrate. By dynamically adjusting illumination conditions, the system maintains measurement precision even during conveyor transport, resolving the contradiction between productivity improvement and measurement accuracy deterioration.

Inventive Principle:
Principle #35Parameter changes

2Speed

If light direction to cubic object fluctuates, then imaging speed is improved, but measurement precision deteriorates due to shading variations

Engineering Contradiction:
Improveimaging speedVSAvoidposition measurement accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The illumination device dynamically adjusts light emission direction and illumination conditions in response to detected positional fluctuations. This dynamic adaptation ensures that optimal illumination is maintained throughout the imaging process, preventing shading variations that would otherwise cause measurement precision deterioration while allowing high-speed imaging to continue.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system detects fluctuations in the positional relationship between the imaging device and substrate, then feeds this information back to the illumination device to adjust illumination conditions. This feedback mechanism ensures that illumination remains optimal despite speed-related positional variations, maintaining measurement precision during high-speed operation.

Inventive Principle:
Principle #23Feedback

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

The system effectively reduces fluctuations in measured positions of cubic elements on substrates by optimizing illumination conditions, ensuring accurate relative position measurements despite variations in the positional relationship between the imaging device and the substrate.

Implementation Method 1

an illumination device (LS) that can be used as a light source for the imaging device (102) to image the workpiece (4)

Methodology Applied
Scientific EffectLight emission: Light

Data Source

PatentEP4597025A1Position measuring system, and illumination condition optimizing system
Publication Date: 2025.08.06 OMRON CORP
  • EP4597025A1 patent drawingFigure 1
  • EP4597025A1 patent drawingFigure 2
  • EP4597025A1 patent drawingFigure 3

AI summary

A position measuring system for measuring, for a workpiece and a shape element having a cubic shape and provided on the workpiece, a relative position of the shape element with respect to the workpiece. The position measuring system includes: an imaging device configured to image the workpiece; an illumination device that can be used as a light source for the imaging device to image the workpiece and change an illumination condition for the workpiece; an image processing unit configured to obtain the relative position by using the image of the workpiece; an illumination condition specifying unit configured to specify a preferred illumination condition of the illumination device under which a fluctuation in the relative position caused by a fluctuation in a positional relationship between the imaging device and the workpiece in imaging the workpiece and obtained by the image processing unit is reduced; and a measurement control unit configured to cause the imaging device to image the workpiece under the preferred illumination condition and cause the image processing unit to obtain the relative position by using the image of the workpiece imaged.