Terahertz Encoder Compressed Scanning Vibration Immunity
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Solution Overview
Problem
Conventional terahertz (THz) sensing systems face challenges in addressing depth variations and raster scanning-induced delays/phase variations due to irregular sample surfaces or mechanical vibrations, limiting their use in harsh environments and applications requiring high-speed absolute positioning.
Innovation Solution
The implementation of a compressed scanning scheme using a single THz transceiver to decode multi-track pseudo-random transmission/reflectance patterns, which reduces maintenance burdens, operates effectively in harsh environments, and supports high-speed absolute positioning systems by eliminating the need for mechanical raster scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a mechanical raster scanning approach is used to inspect the sample surface, then the scanning rate can be fast (up to 1,000 Hz), but depth variations and mechanical vibrations cause phase distortions and sweep distortions in the reflected waveform
Solution Approach 1:
The patent replaces the mechanical raster scanning system with a stationary THz sensing system that uses electronic beam steering or fixed multi-element arrays to achieve spatial mapping without mechanical movement. This substitution eliminates vibration-induced phase distortions while maintaining high-speed measurement capabilities through parallel signal acquisition from multiple sensing elements.
Solution Approach 2:
The patent divides the sensing function into multiple stationary THz sensing elements arranged in arrays, where each element captures reflected waveforms from specific spatial positions. This segmentation allows simultaneous measurement across the sample surface without requiring mechanical scanning, thereby achieving fast scanning rates while eliminating vibration-related measurement errors.
2Device complexity
If a single THz transceiver is used with compressed scanning, then hardware cost and complexity are reduced, but the system must operate effectively in harsh environments with vibration and dust
Solution Approach 1:
The patent employs a stationary compressed sensing architecture that replaces mechanical raster scanning with electronic signal processing. The single THz transceiver remains fixed while using pseudo-random coding and compressed sensing algorithms to reconstruct spatial information, eliminating mechanical components that require maintenance and are susceptible to vibration and dust.
Solution Approach 2:
The patent uses periodic pseudo-random binary sequences as illumination codes, where the reflected signal contains encoded spatial information that can be decoded through correlation processing. This periodic coding scheme enables a single stationary transceiver to extract position and spatial data without mechanical movement, ensuring reliable operation in harsh environments.
3Reliability
If multiple THz transceivers are used to eliminate mechanical scanning, then measurement reliability is improved, but hardware cost and system complexity increase
Solution Approach 1:
The patent combines multiple sensing functions into a single THz transceiver by integrating pseudo-random coding, time-domain gating, and compressed sensing processing. Instead of using multiple independent transceivers, the system merges spatial multiplexing with temporal coding, allowing one transceiver to perform the work of multiple scanners through sophisticated signal processing.
Solution Approach 2:
The patent changes the operational parameters of the single transceiver by using wideband pulsed THz signals with pseudo-random modulation. This parameter change enables the system to achieve high-speed spatial mapping and vibration immunity that would traditionally require multiple transceivers, thereby reducing hardware complexity while maintaining measurement reliability.
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 compressed scanning scheme enables robust, high-speed absolute positioning in harsh environments with reduced hardware costs and complexity, overcoming limitations of mechanical raster scanning and enhancing the operational stability of THz-based systems.
Implementation Method 1
an emitter emits a terahertz (THz) waveform to a scale
Implementation Method 2
a receiver measures amplitudes of the THz waveform reflected from... the scale
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An encoder of a terahertz (THz)-based absolute positioning system used for decoding patterns from THz-band measurements. The encoder includes a scale with a multi-layer reflective/transmissive structure having a matrix with rows. Each row of the matrix corresponds to a plurality of patterns, such that each pattern is used to form a measurement. An emitter emits a THz waveform to the scale. A receiver is used to measure amplitudes of the THz waveform reflected from the scale. A memory stores data including predetermined positions of the emitter based on the patterns of the layers from the scale. Wherein one or more processors can determine a position of the emitter from the measurements of the amplitudes received by the receiver, based on the stored data. An output interface can be used to render the position of the emitter.