Adjustable Two-Dimensional Light Field for Contact Angle Measurement

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Solution Overview

Problem

Existing contact angle measurement apparatuses face precision issues due to reflections on liquid drop surfaces, which affect the accuracy of wettability measurements, especially when using liquids that reflect significant amounts of light.

Innovation Solution

A contact angle measurement apparatus with an illuminating device that provides a two-dimensional light field, adjustable in dimensions, and a controller to minimize reflections by optimizing the light field dimensions based on the drop size, allowing for precise shadow image recording and accurate contact angle determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional illuminating device is used to illuminate the liquid drop, then the measurement can be performed, but reflections occur on the liquid drop surface which disturb the shadow image and reduce measurement precision

Engineering Contradiction:
Improvecontact angle measurement precisionVSAvoidlight reflection on liquid drop
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the illumination parameters by using a two-dimensional light field instead of conventional point or linear light sources. This parameter change in the illumination geometry fundamentally alters how light interacts with the liquid drop surface, minimizing reflections that disturb shadow images while maintaining sufficient illumination for accurate contact angle measurement.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent transitions from conventional one-dimensional or point illumination to a two-dimensional light field illumination approach. This dimensional change in the illumination source creates a more uniform light distribution across the liquid drop surface, reducing specular reflections and improving shadow image quality for precise contact angle determination.

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

2Measurement precision

If the light field dimensions are made adjustable to optimize for different drop sizes, then measurement accuracy improves, but the device complexity increases

Engineering Contradiction:
Improvecontact angle measurement accuracyVSAvoidilluminating device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces dynamic adjustability in the light field dimensions, allowing the illumination area to be adapted to different liquid drop sizes. This dynamic adjustment capability enables optimization of measurement conditions for various drop dimensions while maintaining a relatively simple overall device structure through controlled adaptability.

Inventive Principle:
Principle #15Dynamics

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 apparatus achieves high precision contact angle measurements by minimizing reflections and optimizing the light field dimensions, ensuring accurate wettability assessments even with liquids that reflect light, thereby improving measurement reliability.

Implementation Method 1

an illuminating device (20) adapted and arranged for illuminating each drop applied by the at least one drop dosing device and disposed on the surface from a first side of the at least one drop, and an image recording device adapted and arranged for recording an image of at least a transition region between the surface and each drop applied by the at least one drop dosing device and disposed on the surface in side view from a second side of the drop opposite the first side

Methodology Applied
Scientific EffectShadow imaging: Shadow

Data Source

PatentEP2899529B1Contact angle measurement apparatus
Publication Date: 2016.10.12 KRUSS
  • EP2899529B1 patent drawingFigure 1
  • EP2899529B1 patent drawingFigure 2
  • EP2899529B1 patent drawingFigure 3

AI summary

The present application relates to a contact angle measurement apparatus for measuring a contact angle between a surface (6) of a solid sample body (7) and at least one drop (8) of sample liquid disposed on the surface (6). The apparatus comprises at least one drop dosing device (30) adapted and arranged for applying a drop (8) of a liquid onto a surface (6) of a sample body (7), an illuminating device (20) adapted and arranged for illuminating each drop (8) applied by the at least one drop dosing device (30) and disposed on the surface (6) from a first side of the at least one drop (8), and an image recording device (10) adapted and arranged for recording an image of at least a transition region between the surface (6) and each drop (8) applied by the at least one drop dosing device (30) and disposed on the surface (6) in side view from a second side of the drop (8) opposite the first side. The illuminating device (20) comprises a light-emitting arrangement (21) which, when viewed by the image recording device (10), provides a two-dimensional light field (60). The contact angle measurement apparatus further comprises a controller (39) connected to the illuminating device (20), wherein the controller (39) and the light-emitting arrangement (21) are adapted such that at least one dimension of the light field (60) is selectively adjustable by the controller (39).