Coating Detection on Transparent Sheets Using Triangulation
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Solution Overview
Problem
Current methods for detecting and measuring coatings on transparent sheet materials are slow, inaccurate, and often require physical contact, which can damage the material, and typically require separate devices for thickness and coating determination, limiting their effectiveness in industrial production environments.
Innovation Solution
A device combining triangulation with a coarse spectrometer using multiple LEDs and a 2D CMOS image sensor to simultaneously measure coating presence, type, and thickness on moving transparent sheets without physical contact, allowing for rapid and accurate detection of various coatings, including low emissivity coatings, using LEDs with wavelengths from UV to IR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spectrometer is used to measure coating reflection profiles, then measurement accuracy and resolution are improved, but measurement speed and cost increase significantly
Solution Approach 1:
The patent extracts only the critical wavelength information needed for coating identification from the full spectrum, using a bank of narrowband filters tuned to specific wavelengths rather than measuring the entire spectrum. This extraction approach maintains sufficient measurement accuracy for coating detection while dramatically reducing measurement time and system complexity compared to full spectrometer measurement.
Solution Approach 2:
The patent replaces expensive spectrometer hardware with a more economical array of LED light sources and narrowband optical filters. This substitution uses cheaper, simpler components that can be rapidly switched between wavelengths to achieve the same coating detection function without the high cost and slow measurement speed of traditional spectrometers.
2Measurement precision
If separate devices are used for thickness and coating determination, then measurement specialization is improved, but device complexity and measurement time increase
Solution Approach 1:
The patent merges coating detection and thickness measurement functions into a single integrated device. The same array of LED light sources and photodetector system used for coating reflection profile measurement is also used to measure thickness by analyzing light transmission through the material. This consolidation eliminates the need for separate measurement devices while maintaining measurement accuracy for both parameters.
Solution Approach 2:
The measurement system is designed with multi-functionality, using the same optical components and detection system to perform both coating characterization and thickness measurement. The LED array can illuminate the sample for both reflection-based coating analysis and transmission-based thickness measurement, making the device universal and eliminating the need for multiple specialized instruments.
3Measurement precision
If physical contact measurement instruments are used on sheet material, then measurement capability is improved, but material damage risk increases
Solution Approach 1:
The patent replaces mechanical contact-based measurement instruments with a non-contact optical measurement system. LED light sources illuminate the material surface and photodetectors detect reflected and transmitted light to determine coating properties and thickness. This substitution eliminates physical contact between the measurement device and the material, preventing scratches, dents, or other damage that could occur with mechanical instruments while maintaining measurement 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
Enables rapid, accurate, and non-contact detection of coatings and thickness on transparent sheets, reducing labor and material costs, improving production yield, and decreasing scrap rates by integrating coating and thickness measurement into a single device that can operate on a production line.
Implementation Method 1
light projected from the at least three discrete light sources is reflected from the first surface and the second surface of the transparent sheet and collected by the 2D image generating device
Implementation Method 2
The device combines triangulation with a very coarse spectrometer to provide coating and thickness from the same device
Data Source
AI summary
A method and device are provided for detecting and determining a type of a coating on either surface of a transparent sheet, measuring a thickness of the transparent sheet and measuring a spacing between at least two transparent sheets. The method and device include at least three discrete light sources, a 2D image generating device, a lens, and a processor. A reflected image area from the surfaces of the transparent sheet from each of the at least three discrete light sources produces a sparse spectrometer profile used to detect the coating and to determine the type of coating on either surface of the transparent sheet. A distance between the reflected image position from the at least three discrete light sources from both surfaces of the transparent sheet is used to calculate the thickness of the transparent sheet and the spacing between at least two transparent sheets.