Solid-State Image Pickup Device Parallel Column Output
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Solution Overview
Problem
In X-ray imaging systems, tiling of pixel arrays on multiple substrates results in a dead area at the seam between substrates, leading to incomplete image data, especially in dental cephalography, and causes uneven output times for digital values from substrates with different column counts, prolonging the imaging frame time.
Innovation Solution
The pixel arrays on two substrates are tiled such that the output of digital values is parallelized by dividing the output operation at a column boundary, equalizing the number of columns in each region, and reversing the output order of invalid data regions to synchronize data processing, thereby reducing the imaging frame time and ensuring real-time processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If two substrates are arranged side by side to form a long pixel array, then the imaging coverage is improved, but a dead area is generated at the boundary portion between substrates
Solution Approach 1:
The pixel array is segmented into multiple substrates (first substrate and second substrate) that can be arranged side by side to form a longer imaging device. Each substrate contains a complete pixel array with its own readout circuitry, allowing independent operation and reducing the impact of boundary dead areas on overall imaging coverage.
2Loss of information
If substrates with different column counts are used to tile the pixel array, then the dead area position can be shifted from the center, but the output time for digital values becomes uneven across substrates
Solution Approach 1:
The patent applies preliminary action by performing column reordering within each substrate's pixel array before the parallel output phase. Specifically, columns are rearranged so that substrates with different column counts can output the same number of columns in parallel, eliminating wait states and synchronizing the imaging frame time across all substrates.
Solution Approach 2:
The patent introduces dynamic column reordering capability that allows the system to adaptively adjust the output sequence of columns from different substrates. This dynamic reconfiguration enables optimal parallel processing by matching output volumes across substrates with different physical column counts, thereby synchronizing their operation.
3Adaptability or versatility
If the pixel array is made longer to satisfy imaging requirements, then the imaging application capability is improved, but it becomes difficult to prepare the device on a single substrate
Solution Approach 1:
The patent divides the long pixel array into multiple manageable substrates that can be manufactured separately using standard semiconductor fabrication processes. Each substrate can be produced on conventional wafer sizes, avoiding the need for large-format substrates that are difficult to manufacture. The segmented substrates are then combined to form the complete long-format imaging device.
Solution Approach 2:
The patent employs a nested structure where multiple complete pixel arrays (each containing photodiodes, readout circuits, and support structures) are arranged in sequence along the long dimension. Each substrate acts as a self-contained unit that can be independently manufactured and tested, then integrated into the final long-format device, similar to nested dolls where smaller complete units are arranged within a larger structure.
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 effectively reduces the time required for imaging one frame by synchronizing output operations across substrates and ensures real-time processing by eliminating wait times and aligning invalid data outputs, enhancing the efficiency of X-ray imaging systems.
Implementation Method 1
a scintillator for generating scintillation light in response to incident X-rays to convert the X-ray image into an optical image, and outputting the optical image to the first and second pixel arrays
Data Source
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AI summary
A solid-state image pickup device 1 includes a semiconductor substrate 3A having a pixel array 10A with pixels arrayed in M rows and NA columns, a semiconductor substrate 3B having a pixel array 10B with pixels arrayed in M rows and NB columns, and a first column of which is arranged along an NA-th column of the pixel array 10A, and a signal output section 20. The signal output section 20 outputs digital values corresponding to the respective columns from the first column to the n-th column (2≤n<NA) of the pixel array 10A, sequentially from the n-th column to the first column, and in parallel with this output, outputs digital values corresponding to the respective columns from the n(+1)-th column of the pixel array 10A to the NB-th column of the pixel array 10B, sequentially in a reverse order to that of the first column to the n-th column of the pixel array 10A. Thus, the time required for imaging of one frame is reduced in the solid-state image pickup device with a configuration where pixel arrays formed on two substrates are tiled in their row direction.