Imaging Device Shift Register Midway Charge Discharge
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Solution Overview
Problem
Imaging devices, such as CCD image sensors, face challenges in efficiently discharging unnecessary electric charge from shift registers, which slows down image reading speed.
Innovation Solution
Incorporating an electric-charge discharge portion with a discharge gate in the midway or central portion of the shift register, allowing for controlled discharge of electric charge outside the open-shutter period, thereby reducing the time required to clear unnecessary charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electric charge is transferred serially through the entire shift register to the output end, then all charge can be discharged, but the discharge time becomes excessively long
Solution Approach 1:
The shift register is divided into multiple sections with discharge portions positioned at intermediate locations. Instead of transferring charge serially through the entire register length, charge can be discharged at multiple segmented points along the register, significantly reducing the maximum transfer distance and discharge time while ensuring complete charge evacuation.
Solution Approach 2:
The patent introduces a spatial dimension to the discharge process by placing multiple discharge portions at different locations along the shift register. This transforms the discharge operation from a single sequential endpoint operation into a multi-location parallel operation, reducing the time required for complete charge discharge.
2Productivity
If the discharge gate is opened during the open-shutter period, then unnecessary charge can be discharged, but signal charge may be lost or image quality deteriorates
Solution Approach 1:
The discharge gate is positioned at an intermediate location of the shift register rather than at the output end. This local positioning allows selective discharge of unnecessary charge that has been transferred to intermediate positions, while signal charge intended for the output can be preserved by controlling the timing and position of the discharge gate operation.
Solution Approach 2:
The discharge operation is performed at an intermediate position before charge reaches the final output end. By executing the discharge action preliminarily at an intermediate location, the system can remove unnecessary charge while maintaining the integrity of signal charge that needs to proceed to the output for valid image data.
3Device complexity
If a single discharge portion is provided at the end of the shift register, then the structure is simple, but the discharge time is long and reading speed is reduced
Solution Approach 1:
Multiple discharge portions are distributed along the shift register at intermediate positions. This segmentation creates multiple discharge pathways, allowing charge to be evacuated from different locations simultaneously, thereby reducing the overall discharge time and increasing image reading speed without excessive structural complexity.
Solution Approach 2:
Instead of providing a discharge portion only at the very end of the shift register, the patent places discharge portions at intermediate positions. This partial discharge approach at multiple points along the register reduces the maximum charge transfer distance required, significantly improving discharge speed and image reading performance.
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 significantly reduces the time needed to discharge unnecessary electric charge, enhancing image reading speed by allowing for simultaneous transfer and discharge of signal and unnecessary charges during different periods.
Implementation Method 1
a plurality of light receiving parts for generating electric charge by photoelectric conversion
Data Source
AI summary
An imaging device includes: a plurality of light receiving parts for generating electric charge by photoelectric conversion; a shift register for transferring the electric charge generated by the plurality of light receiving parts to the output-side end portion of the shift register; and an electric-charge discharge portion which is provided in a midway-portion of the shift register and includes an electric-charge discharge gate for controlling import of the electric charge from the shift register for discharging the electric charge of the shift register via the electric-charge discharge gate.