Continuous-Wave THz 3D Imaging System Using Wavelength-Swept Laser
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Solution Overview
Problem
Current 3D imaging technologies using THz beams face limitations in speed and precision due to the need for physical movement of samples and the use of pulse wave THz beams, which increases costs and restricts miniaturization, while existing methods like CT and OCT have long image acquisition times and limited applicability across industries.
Innovation Solution
A high-speed 3D imaging system utilizing a continuous-wave THz beam scan, generated by a wavelength-fixed and wavelength-swept laser, which adjusts the direction of the THz beam using a galvanometer scanner and telecentric f-θ lens to acquire 3D images without physically moving the sample, enabling faster and more precise measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CT technology is used to obtain 3D images by acquiring hundreds to thousands of 2D projection images at different angles, then comprehensive 3D structural information is obtained, but image acquisition time becomes too long for industrial applications
Solution Approach 1:
The patent extracts only the essential information needed for 3D reconstruction by using a limited number of projection angles combined with depth scanning, rather than acquiring hundreds or thousands of projections as in traditional CT. This extraction approach maintains sufficient 3D structural information while dramatically reducing acquisition time for industrial applications.
Solution Approach 2:
Instead of performing the complete 360-degree multi-angle scanning required by traditional CT, the patent uses partial scanning with a limited angular range combined with depth information acquisition. This partial action approach achieves acceptable 3D reconstruction quality much faster, trading off some angular coverage for significant time savings suitable for industrial settings.
2Object-affected harmful factors
If OCT technology is used to image micro structures in biological tissue, then tissue damage is minimized, but imaging depth is limited to only several millimeters
Solution Approach 1:
The patent changes the imaging modality from optical wavelengths (OCT) to terahertz wavelengths, which have different penetration characteristics. This parameter change in the electromagnetic spectrum allows deeper imaging penetration while maintaining non-contact and non-destructive measurement capabilities, overcoming the depth limitation of OCT technology.
3Measurement precision
If pulse wave THz beam is used for 3D imaging, then depth information can be obtained, but system cost increases and miniaturization is restricted
Solution Approach 1:
The patent replaces the complex pulse wave generation and time-domain detection system with a continuous wave THz beam system using frequency modulation and heterodyne detection. This substitution eliminates the need for pulsed lasers and time-gated detectors, significantly reducing system cost and enabling miniaturization while maintaining depth measurement capability through frequency-based encoding.
Solution Approach 2:
The patent changes from time-domain pulse measurement to frequency-domain continuous wave measurement. By modulating the THz beam frequency and using heterodyne detection, depth information is encoded in frequency shifts rather than time delays, simplifying the system architecture and enabling more compact, cost-effective implementation.
4Reliability
If X-ray technology is used to acquire projection images, then transmission through materials is achieved, but biological safety is compromised due to high photon energy
Solution Approach 1:
The patent changes the electromagnetic radiation parameter from high-energy X-rays to low-energy terahertz waves. This parameter change in the electromagnetic spectrum maintains the ability to transmit through non-conductive materials while dramatically reducing photon energy to levels that are safe for biological tissues, eliminating the harmful effects of X-ray exposure.
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 significantly reduces measurement time, enhances precision, and improves the detectable depth range compared to existing THz beam technologies, while being cost-effective and suitable for various industrial applications, avoiding damage to biological tissues.
Implementation Method 1
a wavelength-fixed laser generating first laser light having a first fixed wavelength; a wavelength-swept laser generating second laser light having a second wavelength varying from a preset minimum wavelength to a preset maximum wavelength at a high speed for one period
Implementation Method 2
an emitter receiving the first laser light and the second laser light to output a continuous-wave THz beam having a frequency corresponding to a difference between a frequency corresponding to the first wavelength and a frequency corresponding to the second wavelength
Implementation Method 3
a galvanometer scanner receiving the THz beam to adjust a direction angle of the THz beam
Implementation Method 4
a telecentric f-θ lens projecting the THz beam of which the angle is adjusted by the galvanometer scanner onto an imaging plane
Implementation Method 5
a detector receiving the THz beam reflected from the imaging target to generate a reflected signal
Data Source
AI summary
Provided is a high-speed 3D imaging system using continuous-wave THz beam scan, and more particularly, a high-speed 3D imaging system using continuous-wave THz beam scan capable of acquiring a 3D image for a sample at a high speed and high precision by measuring a signal reflected from a sample using the continuous-wave THz beam generated from a wavelength-fixed laser and a wavelength-swept laser and having a frequency varying at a high speed to obtain depth direction information on a sample and performing a 2D scan on the sample using a THz beam scanner.