TDI Detector Sub-Arrays for Charge Transfer Efficiency
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Solution Overview
Problem
Conventional imaging devices with charge couple devices (CCDs) in a Time Delay and Integration (TDI) configuration require multiple charge transfers across a large number of detectors, leading to reduced overall charge transfer efficiency, increased operational voltage, and shorter operational life due to radiation exposure, especially in satellite imaging applications.
Innovation Solution
The imaging device divides detector arrays into sub-arrays with each detector in a TDI configuration, allowing image signals to be extracted from each sub-array, reducing the number of detectors in TDI configuration while maintaining the same total number of detectors, thereby increasing overall charge transfer efficiency and reducing operational voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the number of detectors in TDI configuration is increased to maintain low-light imaging capability, then the low-light imaging capability is improved, but the overall charge transfer efficiency deteriorates due to multiple charge transfers
Solution Approach 1:
The detector array is divided into multiple independent detector sub-arrays, each capable of generating image signals separately. This segmentation allows the system to maintain low-light imaging capability through sufficient detector elements while reducing the number of charge transfers needed in each TDI configuration sub-array, thereby improving overall charge transfer efficiency.
2Illumination intensity
If the number of detectors in TDI configuration is increased to maintain low-light imaging capability, then the low-light imaging capability is improved, but the operational life deteriorates due to radiation exposure
Solution Approach 1:
By segmenting the detector array into multiple sub-arrays, the patent reduces the number of detectors that must undergo multiple charge transfers in TDI configuration. This decreases cumulative radiation exposure per detector sub-array, extending operational life in radiation-prone environments like space, while maintaining sufficient detectors per sub-array to preserve low-light imaging capability.
3Illumination intensity
If the number of detectors in TDI configuration is increased to maintain low-light imaging capability, then the low-light imaging capability is improved, but the operational voltage increases
Solution Approach 1:
The patent divides the detector array into multiple sub-arrays, reducing the number of detectors in each TDI configuration. This reduction decreases the voltage required for charge transfer operations in each sub-array, lowering overall operational voltage and energy consumption, while maintaining sufficient detector elements to preserve low-light imaging capability.
4Productivity
If charge transfer occurs multiple times across the entire detector array, then an image signal can be extracted, but the device complexity increases
Solution Approach 1:
By dividing the detector array into multiple independent sub-arrays that can be processed separately, the patent reduces the complexity of charge transfer operations. Each sub-array requires fewer charge transfers and can be handled by dedicated readout circuits, simplifying the overall system architecture while maintaining image signal extraction capability.
Solution Approach 2:
The patent combines the outputs of multiple detector sub-arrays to generate the final image signal. This merging approach allows parallel processing of multiple sub-arrays with reduced complexity each, while achieving the same productivity as a single large-scale TDI configuration through distributed processing.
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 enhances overall charge transfer efficiency, extends operational life by reducing radiation effects, and lowers the voltage required for charge transfer, allowing for more reliable and efficient low-light imaging in harsh environments like space.
Implementation Method 1
Each detector of the detector array is operable to receive a charge generated by incident photons
Data Source
AI summary
In certain embodiments, an imaging device includes an image sensor that includes a detector array. The detector array includes a plurality of detectors operable to receive a charge generated by light. The detector array also includes a plurality of detector sub-arrays each including one or more of the plurality of detectors. The one or more detectors of each detector sub-array are in a time delay and integration (TDI) configuration. The image sensor of the imaging device is operable to, for each of the plurality of detector sub-arrays of the detector array, generate an image signal corresponding to a scan of an object.