Reversible CCD Imaging Device for High-Speed TDI Operations
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Solution Overview
Problem
Conventional solid-state imaging devices require significant time for imaging large areas due to the fixed direction of charge transfer in CCDs, necessitating device movement to capture images from one end to the other and back, which prolongs the imaging process.
Innovation Solution
A solid-state imaging device with first and second signal readout circuits at each end of the column direction, connected to semiconductor elements for serial signal output, allowing for reversible CCD charge transfer direction, enabling high-speed and low-noise readout and reducing the need for device movement during TDI operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the CCD charge transfer direction is fixed, then the device structure is simple, but the imaging time for large areas increases significantly
Solution Approach 1:
The imaging device is segmented into multiple independent charge transfer paths with separate readout circuits. The pixel array is divided into first and second regions, each with its own charge transfer path and readout circuit, allowing parallel or alternating operation to image large areas faster without requiring a single complex movable structure.
Solution Approach 2:
The patent introduces dynamic switching capability between fixed charge transfer directions. By using a transfer control circuit that can dynamically select between first and second charge transfer paths, the system achieves adaptive imaging without mechanical movement, resolving the contradiction between fixed structure and flexible imaging requirements.
2Area of stationary object
If the solid-state imaging device moves to capture images from one end to the other, then the imaging coverage increases, but the imaging time prolongs
Solution Approach 1:
The pixel array is segmented into first and second regions that can be imaged simultaneously or alternately through separate charge transfer paths. This allows the device to cover large areas without mechanical movement, as multiple regions are processed in parallel or rapid succession, eliminating the time loss associated with moving the device between imaging positions.
Solution Approach 2:
The patent enables continuous imaging of large areas by maintaining active charge transfer and readout operations across multiple pixel regions without interruption. The transfer control circuit ensures that while one region is being read out, another region can begin charge transfer, creating a continuous imaging process that eliminates idle movement time.
3Productivity
If readout circuits are arranged at one end only, then the device structure is simple, but the readout noise increases and speed decreases
Solution Approach 1:
The readout function is segmented into multiple independent readout circuits distributed at different ends of the pixel array. Instead of all signals converging at one end, the first and second readout circuits are positioned at opposite ends, allowing signals to be read out in parallel from multiple locations, thereby increasing readout speed without significant structural complexity.
Solution Approach 2:
The patent transitions from a one-dimensional readout architecture (all signals to one end) to a two-dimensional readout architecture (signals to multiple ends). By distributing readout circuits across different spatial locations in the pixel array, the system achieves faster readout speeds and reduced noise through parallel processing, with the added complexity being minimal and well-justified by the performance gains.
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 configuration allows for efficient imaging of large areas with high spatial resolution in a shorter time by reversing the CCD charge transfer direction, reducing the time required for imaging and enabling coincident transfer speed and direction with moving subjects.
Implementation Method 1
a CCD-type solid-state imaging element (10) having an imaging plane (12) formed of M x N pixels (13) two-dimensionally arrayed in M rows and N columns
Data Source
AI summary
A solid-state imaging device 1A includes a CCD-type solid-state imaging element 10 having an imaging plane 12 formed of M×N pixels that are two-dimensionally arrayed in M rows and N columns, N signal readout circuits 20 arranged on one end side in the column direction for each of the columns with respect to the imaging plane 12, and N signal readout circuits 30 arranged on the other end side in the column direction for each of the columns with respect to the imaging plane 12, a semiconductor element 50 for digital-converting and then sequentially outputting as serial signals electrical signals output from the signal readout circuits 20 for each of the columns, and a semiconductor element 60 for digital-converting and then sequentially outputting as serial signals electrical signals output from the signal readout circuits 30 for each of the columns.