Solid-State Imaging Device Bi-Directional Charge Transfer
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Solution Overview
Problem
Existing solid-state imaging devices face limitations in transferring and reading out electric charges due to the need to change six-phase voltages in both the imaging and buffer areas, which hinders the speed-up of charge readout.
Innovation Solution
A solid-state imaging device with a photoelectric converting section, transfer section, first and second buffer sections, and output sections, where the transfer section uses three-phase or four-phase drive signals for bi-directional charge transfer, and the buffer sections use two-phase drive signals for high-speed transfer and output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If six-phase drive voltages are applied to both imaging area and buffer area for charge transfer, then charge transfer is enabled, but transfer time increases and readout speed is hindered
Solution Approach 1:
The patent divides the charge transfer system into two distinct sections: the imaging area using six-phase drive voltages for precise bi-directional transfer, and the buffer area using simplified two-phase drive voltages for rapid charge movement. This segmentation allows each region to be optimized independently, resolving the contradiction between transfer precision and speed.
Solution Approach 2:
Different drive voltage schemes are applied to different spatial regions: the imaging area receives six-phase voltages for controlled bi-directional transfer, while the buffer area receives two-phase voltages for high-speed unidirectional transfer. This local differentiation enables simultaneous optimization of transfer control and readout speed in different locations.
2Productivity
If multiple readout amplifiers are provided horizontally for multi-port output, then readout speed is improved, but device complexity increases
Solution Approach 1:
The patent extracts the high-speed transfer function from the imaging area and places it in the buffer area using two-phase drive voltages. This allows charges to be rapidly moved to buffer registers before readout, enabling faster overall readout performance without requiring multiple complex readout amplifier circuits in the imaging area.
Solution Approach 2:
The buffer area acts as an intermediary between the imaging area and the readout amplifiers. Charges are first transferred to the buffer area using simplified two-phase voltages, then read out through the amplifiers. This intermediary structure decouples the transfer and readout functions, improving readout speed without proportionally increasing device complexity.
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
Enables bi-directional transfer and high-speed readout of electric charges by optimizing the drive signals for transfer and buffer sections, allowing for faster charge transfer and output without prolonged output times.
Implementation Method 1
a photoelectric converting section provided so as to extend along a first direction and configured to generate an electric charge in response to incidence of light
Data Source
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AI summary
A solid-state imaging device 1 includes photoelectric converting sections 11, 12, transfer sections 21, 22, first buffer sections 31, 32, second buffer sections 51, 52, first output sections 40, and second output sections 60. The photoelectric converting sections 11, 12 generate electric charges in response to incidence of light. The transfer sections 21, 22 transfer the generated electric charges in a first direction or in a second direction opposite thereto in response to three-phase or four-phase drive signals. The first buffer sections 31, 32 and the second buffer sections 51, 52 acquire the electric charges transferred in the first and second directions, respectively, by the transfer sections 21, 22 and transfer the acquired electric charges in the first and second directions, respectively, in response to two-phase drive signals. The first output sections 40 and the second output sections 60 acquire the electric charges transferred from the first buffer sections 31, 32 and from the second buffer sections 51, 52, respectively, and output signals according to the acquired electric charges.