Active Terahertz Imager Array Without Mechanical Scanning
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Solution Overview
Problem
Current THz imagers face limitations in lateral resolution and are unsuitable for close-range or contact imaging due to the need for mechanical scanning, large optics, and low signal-to-noise ratios at room temperature, which restrict their application in achieving high frame rates and accurate imaging.
Innovation Solution
An active imager design featuring a substrate with closely arranged electrical emitting and detecting units, including antennas, metallic reflectors, and dielectric elements, allowing for simultaneous emission and detection of THz radiation without the need for collimating optics, enabling high-resolution imaging at wavelengths comparable to the imaged radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical scanning is used to image the sample, then the imager can operate at room temperature, but the frame rate is limited and imaging time is excessive
Solution Approach 1:
The imager divides the imaging function into multiple independent sensor elements arranged in an array, with each element capable of simultaneous operation. This segmentation eliminates the need for mechanical scanning while maintaining room temperature operation, thereby increasing frame rate without excessive complexity
Solution Approach 2:
The patent replaces the mechanical scanning system with an electronic array-based detection system. Instead of mechanically moving a single sensor across the sample, multiple sensors simultaneously detect THz radiation from different positions, substituting mechanical motion with parallel electronic detection to achieve high frame rates
2Measurement precision
If large diameter lenses are used to collimate THz radiations, then the radiations can be effectively focused, but the distance between sensing elements must be several wavelengths, limiting lateral resolution
Solution Approach 1:
The patent extracts and removes the large collimating lenses from the imaging system. By eliminating these optical elements, the system can place sensor elements much closer together (less than several wavelengths apart), thereby achieving lateral resolution at the wavelength scale without the constraints imposed by large optics
Solution Approach 2:
The patent transitions from optical-dimensional focusing (using large lenses) to sub-wavelength dimensional sensing (using closely spaced antenna elements). This dimensional change allows the system to achieve high lateral resolution by operating at the antenna element scale rather than the optical focus scale
3Ease of operation
If THz radiations are used for direct imaging at room temperature, then the system is less cumbersome than cryogenic cooling, but the signal-to-noise ratio is too low to extract signals from background noise
Solution Approach 1:
The patent changes the operational parameters of the sensor elements by using resonant antenna structures tuned to specific THz frequencies. This resonant operation enhances the signal-to-noise ratio at room temperature by selectively amplifying the desired THz signal while suppressing background noise, maintaining ease of operation without sacrificing reliability
4Measurement precision
If the diameter of the lens is larger than several wavelengths, then the lens can effectively collimate radiations, but the lateral resolution is limited to several times the imaging wavelengths
Solution Approach 1:
The patent extracts and eliminates the large-diameter lenses from the system. By removing these bulky optical components, the system achieves lateral resolution limited only by the antenna element spacing rather than the lens diameter, thereby achieving wavelength-scale resolution without large optics
Solution Approach 2:
The patent applies local quality by using individually optimized antenna elements at each sensor position rather than a single large optical element. Each antenna element is locally tuned to the imaging wavelength, enabling high resolution without requiring a large overall system footprint
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 design enhances lateral resolution to the order of the imaging wavelength, enabling high-resolution imaging in close proximity to or in contact with the sample, and achieves improved signal-to-noise ratios without mechanical scanning or large optics, facilitating faster and more accurate imaging.
Implementation Method 1
Each emitting unit includes an electrical emitter, a first antenna... for emitting electromagnetic waves
Implementation Method 2
a first metallic reflector, and a first dielectric element between the first antenna and the first metallic reflector
Implementation Method 3
a first dielectric element between the first antenna and the first metallic reflector
Implementation Method 4
Each detecting unit includes an electrical detector, a second antenna... for detecting the electromagnetic waves reflected by the object
Implementation Method 5
a second metallic reflector, and a second dielectric element between the second antenna and the second metallic reflector
Implementation Method 6
a second dielectric element between the second antenna and the second metallic reflector
Data Source
AI summary
An imager for obtaining an image of an object includes a substrate including a plurality of electrical emitting units for emitting electromagnetic waves and a plurality of electrical detecting units for detecting the electromagnetic waves reflected by the object. Each emitting unit includes an electrical emitter, a first antenna, a first metallic reflector, and a first dielectric element between the first antenna and the first metallic reflector. Each detecting unit includes an electrical detector, a second antenna, a second metallic reflector, and a second dielectric element between the second antenna and the second metallic reflector.