CCD Pixel Charge Merging for Transfer Speed and Dynamic Range
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Solution Overview
Problem
Existing image capture devices using CCD solid state image capture elements face challenges in achieving high-quality images due to long vertical transfer times, smear noise, and limited sensitivity and dynamic range, especially when capturing high-brightness subjects or continuous light exposure.
Innovation Solution
The image capture device employs a shift register with multiple pixels and transfer electrodes, where information charges are stored in potential wells and combined during transfer, allowing for faster transfer speeds and increased sensitivity and dynamic range by controlling clock pulses to manage charge storage and transfer efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If information charges are transferred sequentially from each pixel to the next, then the transfer process is simple, but the vertical transfer time becomes long and smear noise increases
Solution Approach 1:
The patent combines information charges from multiple pixels (specifically three pixels: first, second, and third pixels) into a single potential well before transfer. This merging approach allows parallel processing of multiple pixels' charges simultaneously, significantly reducing the vertical transfer time compared to sequential transfer, while maintaining manageable transfer complexity through structured combination operations.
2Reliability
If a single pixel stores information charges, then the structure is simple, but the sensitivity and dynamic range are limited
Solution Approach 1:
The patent merges information charges from multiple pixels into a single potential well, effectively increasing the charge storage capacity. This combination enhances sensitivity and dynamic range because the potential well can accommodate larger total charge amounts from multiple pixels, while the structured merging process keeps the device complexity manageable through systematic charge combination operations.
3Object-affected harmful factors
If transfer electrodes are used to store and transfer information charges, then the transfer process is efficient, but smear noise occurs during long exposure periods
Solution Approach 1:
The patent performs preliminary combination of information charges from multiple pixels into a single potential well before the transfer process begins. By pre-combining charges in the image capture section, the subsequent transfer operation is completed more quickly, reducing the time that transfer electrodes are active and thereby minimizing smear noise generation during the transfer process.
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 reduces smear noise and enhances image quality by enabling faster transfer of information charges and increased sensitivity and dynamic range, allowing for high-quality image capture even under challenging lighting conditions.
Implementation Method 1
Light incident on the image capture section 2i is subjected to photoelectric conversion in the light receiving pixels so that information charges are generated
Implementation Method 2
a potential well formed by function of the transfer electrodes is used to store and transfer information charges generated in response to light incident on a pixel
Data Source
AI summary
An image capture device capable of capturing high quality images is disclosed. The image capture device comprises a shift register, each pixel of which has a plurality of transfer electrodes extending in a direction crossing a transfer direction of information charges. A potential well formed by function of the transfer electrodes is used to store and transfer information charges generated in response to light incident on a pixel. In this image capture device, during image capture, information charges are stored in a plurality of potential wells substantially separated from each other, and, during transfer, information charges stored in at least two of the plurality of potential wells are combined by addition to be transferred.