Deformable THz Reflector for Misaligned Object Measurement
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Solution Overview
Problem
Existing THz measuring devices face inaccuracies in determining layer thickness and distance of hollow cylindrical objects due to misalignment, which reduces signal strength and precision, especially when the objects have offsets, flat areas, or oval shapes, and are not centered within the device.
Innovation Solution
A THz measuring device with a deformable reflector in the beam path allows for adjustable beam cross-section and focusing plane, enabling perpendicular incidence of Terahertz radiation on the object's surfaces, even when the object is not perfectly aligned, by deforming a mirror or lens to adapt the beam shape and position dynamically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the Terahertz radiation is focused onto the central axis of the hollow cylindrical measurement object using a fixed optical unit, then the signal strength is maximized when the object is perfectly aligned, but the measurement precision deteriorates when the object has offsets, flat areas, or oval shapes
Solution Approach 1:
The optical unit is made dynamically adjustable, allowing the optical axis to be repositioned and the beam cross-section to be reshaped in real-time. This enables the system to adapt to different object positions and geometries, maintaining both high signal strength and measurement precision across various measurement scenarios
Solution Approach 2:
The system changes optical parameters (optical axis position, beam cross-section shape and size) dynamically to match the measurement requirements. By adjusting these parameters, the system can accommodate objects with offsets, flat areas, or oval shapes while maintaining accurate measurements
2Adaptability or versatility
If the optical unit is made adjustable to accommodate object misalignment, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The optical unit is designed to perform multiple functions: positioning the optical axis, shaping the beam cross-section, and focusing the radiation. By consolidating these functions into a single adjustable unit, the system achieves high adaptability without proportionally increasing overall device complexity
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 solution ensures high signal strength and precise determination of layer thickness and distance measurements, regardless of the object's position or surface irregularities, by optimizing the beam path and focusing plane to maintain perpendicular reflection and efficient signal detection.
Implementation Method 1
a deformable reflector, for example a mirror, is arranged in the beam path of the transmitter and receiver unit by means of which a beam cross-section of the irradiated Terahertz radiation for testing the measurement object can be changed
Implementation Method 2
the measurement object is made of a material transparent for Terahertz radiation, e.g. plastics, which has a refraction index for Terahertz radiation markedly higher than for air or vacuum. Consequently, part of the irradiated Terahertz radiation is reflected upon entering the material layer of the measurement object and part of it penetrates the material layer
Implementation Method 3
The reflected Terahertz radiation can be detected using a Terahertz receiver in the transmitter and receiver unit and thereupon a measuring signal in temporal resolution can be put out. Hereby, in temporal progression, measuring peaks will appear for each reflection on one of the boundary surfaces. A run-time for a double pass through the material layer ca be deduced from the time-of-flight difference between adjacent measuring peaks
Data Source
AI summary
The invention relates to a THz measuring device for measuring a layer thickness of a wall (4a) of a measurement object (4) and/or of a distance (18) between boundary surfaces (4a, 4b) of a measurement object (4), comprising a transmitter and receiver unit (2) including a Terahertz-Sender and a Terahertz receiver, a controller means configured to determine the layer thickness of the wall (4a) of the measurement object (4) and/or a distance (18) between boundary surfaces (4b, 4c) of the measurement object (4) from a time-of-flight difference of the Terahertz radiation reflected on a first boundary surface (4b, 4c) of the wall (4a) of the measurement object (4) and the Terahertz radiation reflected on a second boundary surface (4b, 4c) of the wall (4a), where in the beam path (5) of the at least one transmitter and receiver unit (2) an adjustable optical unit (7) including a reflector is arranged, where a surface of the reflector is designed to deflect the irradiated Terahertz radiation and/or the Terahertz radiation reflected from the respective boundary surface (4b, 4c) for adjusting the optical axis (C) of the transmitter and receiver unit (2).Hereby, according to the invention, it is provided that the reflector is designed to be deformable so that a beam cross-section of the irradiated Terahertz radiation can be modified in a focusing plane (17) lying downstream from the reflector in the radiation direction of the irradiated Terahertz radiation, the focusing plane being adjustable by deforming the reflector.