Solid-State Imaging Element Charge Readout Speed Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solid-state image pickup devices face challenges in achieving both high charge readout speed and controlled charge accumulation time, as charges generated in photodiodes tend to move towards the readout gate, making it difficult to reverse the flow and sweep away unnecessary charges effectively.
Innovation Solution
A solid-state image pickup device design where photoelectric converters are aligned with a potential gradient across one direction, featuring a transferring section for quick charge readout and an unnecessary charge discharging drain with a gate that selectively controls the flow of charges, allowing for both efficient charge transfer and discharge of accumulated charges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a potential gradient is formed to increase charge readout speed, then charges move quickly toward the readout gate, but it becomes difficult to reverse the flow and sweep away unnecessary charges
Solution Approach 1:
The invention divides the charge handling function into separate pathways: a first drain region for necessary charges and a second drain region for unnecessary charges. This segmentation allows independent control of charge flows, enabling the system to maintain high readout speed while selectively sweeping away unnecessary charges without reversing the main potential gradient.
Solution Approach 2:
The invention introduces a gate electrode as an intermediary control element between the photoelectric converter and the drain regions. By controlling the potential of this gate, the system can selectively open or close pathways for necessary versus unnecessary charges, achieving flexible charge flow control while maintaining the overall potential gradient for high-speed readout.
2Duration of action of moving object
If charges are allowed to accumulate in the photodiode, then charge accumulation time is extended, but charge readout speed decreases
Solution Approach 1:
The invention dynamically controls the potential barriers of the gate electrode to adaptively manage charge accumulation and readout. During accumulation, the gate potential is adjusted to allow charge buildup; during readout, the gate potential is changed to facilitate rapid charge discharge. This dynamic control enables the system to achieve both extended accumulation time and high readout speed without compromise.
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 design enables controlled charge accumulation time while maintaining high charge readout speed, ensuring efficient charge handling and preventing unwanted charge flow between photoelectric converters.
Implementation Method 1
photoelectric converters aligned in a predetermined direction
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A solid-state image pickup device 1 includes: a plurality of photoelectric converters 2 which are aligned in a predetermined direction and have a potential made higher toward one side of a direction crossing the predetermined direction; a transferring section 6 which is provided on one side of the photoelectric converters 2 in the direction crossing the predetermined direction and transfers charges generated in the photoelectric converters 2 in the predetermined direction; an unnecessary charge discharging drain 7 which is provided adjacent to the photoelectric converter 2 along the direction crossing the predetermined direction and discharges unnecessary charges generated in the photoelectric converter 2 from the photoelectric converter 2; and an unnecessary charge discharging gate 8 which is provided between the photoelectric converter 2 and the unnecessary charge discharging drain 7 and selectively performs cutting-off and release of the flow of unnecessary charges from the photoelectric converter 2 to the unnecessary charge discharging drain 7.