A-TIR Contact Angle Measurement for Small Droplets
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Solution Overview
Problem
Current methods for evaluating features of liquid droplets and surfaces, such as contact angle and thickness, are complex and time-consuming, requiring sophisticated microscope systems and are limited to small areas, making real-time evaluation on large scales and transparent samples challenging, especially for small defects and turbid mediums like human sebum in fingerprints.
Innovation Solution
The use of aperture total internal reflection (A-TIR) and modified Fresnel equation modeling, combined with 3-D ray tracing and interference fringe techniques, allows for the measurement of small contact angles and thicknesses without the need for complex microscopy, enabling real-time monitoring and full-field evaluation of droplet and surface features, including those on opaque and transparent samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sophisticated microscope systems are used to evaluate contact angles and surface defects, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent replaces complex mechanical microscope systems with a simplified optical setup using a digital camera, light source, and image processing algorithms. The contact angle measurement system uses a camera to capture droplet images and calculates contact angles through image analysis, eliminating the need for sophisticated mechanical microscopy while achieving comparable or superior precision.
Solution Approach 2:
The patent creates a digital copy (image) of the droplet and surface features, then analyzes this copy through image processing to extract measurement data. This approach allows precise measurement of contact angles and surface defects by working with digital representations rather than direct optical observation, simplifying the physical measurement system.
2Area of stationary object
If current scanning methods are used to evaluate large surface areas, then measurement coverage is improved, but real-time evaluation capability deteriorates due to time-consuming scanning
Solution Approach 1:
The patent implements periodic imaging at multiple angles (e.g., 0°, 45°, 90°, 135°) to capture comprehensive surface information. By taking a series of images at different angles and processing them together, the system achieves full-field evaluation of large surfaces while maintaining real-time capability, as all images are captured simultaneously or in rapid succession rather than requiring sequential scanning.
Solution Approach 2:
The patent transitions from single-angle scanning to multi-angle imaging, adding the angular dimension to the measurement process. By capturing images from multiple perspectives and integrating the data, the system evaluates entire surface areas in real-time rather than scanning point-by-point, effectively using angular diversity to achieve comprehensive coverage.
3Reliability
If steam-condensation generation methods are used for defect detection, then defect detection capability is improved, but production time increases and surface staining occurs
Solution Approach 1:
The patent changes the physical parameters of the test droplet by using liquids with different surface tensions, contact angles, and evaporation rates. Instead of relying on steam condensation, the system uses pre-formed droplets with controlled properties that provide immediate defect detection without requiring evaporation time. By selecting appropriate liquid parameters, the system achieves reliable defect detection while eliminating the time loss associated with droplet evaporation.
4Adaptability or versatility
If conventional optical methods are used for transparent samples, then transmission mode measurement is possible, but reflection mode capability for opaque samples is limited
Solution Approach 1:
The patent creates a universal measurement system that can handle both transparent and opaque samples through a single apparatus. By incorporating both transmission and reflection imaging modes with a digital camera system, the patent enables the same device to measure contact angles and surface features across diverse sample types without requiring separate specialized equipment, thereby achieving both versatility and precision.
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 effectively measures contact angles as low as 1 degree and thicknesses less than 5 microns, improving surface coating efficiency and production time, and accurately characterizes fingerprint patterns and droplet morphological features, overcoming limitations of existing techniques.
Implementation Method 1
The A-TIR technique utilizes the internal reflection interference technique to determine other droplet morphological features such as the contact angle, the thickness of the precursor, and the droplet profiles
Implementation Method 2
The described methods can effectively measure the droplet height from 1 micron to 16 microns with a contact angle from 2.5 to 17 degrees
Implementation Method 3
3-D ray tracing and modified Fresnel equation modeling
Data Source
AI summary
The present disclosure relates to methods for evaluating features of objects such as liquid droplets and surfaces. More particularly, the present disclosure relates to methods for measuring features such as the contact angle and the thickness of an object such as a liquid droplet or a fingerprint as well as related compositions for evaluation.