Synchronized THz Transceivers for Layer Thickness and Defect Measurement
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Solution Overview
Problem
Existing THz measurement technologies face challenges in accurately measuring objects with defects and materials with unknown temperatures and varying absorption properties, requiring complex alignment and multiple reflections, which can lead to inaccurate measurements.
Innovation Solution
A THz measuring device and method using synchronized THz transceivers that emit and receive THz radiation through a measuring chamber, allowing for precise measurement of objects by determining total and wall transit times, with the ability to detect defects and material properties, and employing frequency modulation for enhanced accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple reflections are used to measure objects with defects, then measurement coverage is improved, but measurement accuracy deteriorates due to signal degradation
Solution Approach 1:
The measurement process is divided into two distinct parts: a calibration measurement without the object to establish reference values, and a subsequent object measurement. This segmentation allows the system to separate the complex multi-reflection signal path from the reference, enabling accurate defect detection even with multiple reflections.
Solution Approach 2:
A calibration measurement is performed beforehand to determine reference values for the empty measuring chamber. These pre-established reference values are then used to compare against object measurements, compensating for signal degradation from multiple reflections and enabling accurate defect detection.
2Measurement precision
If complex alignment of components is performed, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The same THz transceiver is used for both calibration measurements and object measurements, performing multiple functions with a single device. This eliminates the need for separate reference and measurement systems, reducing alignment complexity while maintaining measurement capability.
Solution Approach 2:
Instead of using separate transceivers for reference and object measurements, the invention inverts the approach by using one transceiver for both purposes, first measuring the empty chamber and then measuring objects in the same chamber with the same device.
3Adaptability or versatility
If materials with unknown temperatures and varying absorption are measured, then adaptability is improved, but measurement accuracy deteriorates due to unknown material properties
Solution Approach 1:
The system measures the actual transit time of THz radiation through the material and uses this measured parameter, rather than relying on predetermined material properties. This allows accurate measurement of materials with unknown temperatures and varying absorption characteristics by directly measuring the effect rather than assuming known parameters.
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 accurate and efficient measurement of geometric and material properties of objects, including defects, with reduced complexity and improved signal strength, even in conditions of high absorption and material variation.
Implementation Method 1
If the speed of light of the THz radiation in the material is known, layer thicknesses and/or diameters can be determined from the measured differences in the transit time of the detected THz radiation
Implementation Method 2
The THz radiation can then be reflected at interfaces and subsequently detected
Implementation Method 3
This results in a measurement signal with a total internal reflection peak
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a THz measuring device (2) for measuring a measurement object (12), comprising a measuring chamber (5) for receiving a measurement object (12), which is formed between a first THz transceiver (3) and an opposing second THz transceiver (4), wherein the THz transceivers (3, 4) each emit and receive THz radiation (8) into the measuring chamber (5), a synchronizing device (6) synchronizes the transmission times and/or measurement times of the two transceivers (3, 4), and a detection device (20) receives measurement signals (M1, M2) from the THz transceivers (3, 4) and determines at least one layer thickness (WD1, WD2) and/or at least one layer property (n12, v12) from at least the following measurements: - a blank measurement in which the first THz transceiver (3) emits the THz radiation (8) through the empty measuring chamber (5) outputs to the second THz transceiver (4) and the second THz transceiver measures an idle time (T_Idle), - a measurement of the total time,in which the first THz transceiver (3) outputs the THz radiation (8) through the measurement room (5) and the object under test to the second THz transceiver (4) and the second THz transceiver measures a transit time with the object under test (T_12), and - at least one wall area measurement (ST3, ST4) in which the first and/or second transceiver (3, 4) outputs THz radiation (8) and detects the THz radiation reflected at interfaces (14a, 14b) of at least one wall area (12a, 12b).