Solid-state imaging device charge transfer segmentation
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Solution Overview
Problem
Solid-state imaging devices face limitations in transferring signal charges from photoelectric conversion elements due to constraints on the capacitance of floating diffusion capacitors and power source voltage, which restricts charge-to-voltage conversion efficiency and sensitivity adjustments based on light intensity.
Innovation Solution
A method involving a solid-state imaging device with a pixel array and transfer elements that utilize multiple control voltages to transfer signal charges in batches, allowing for arbitrary quantities to be transferred, enabling efficient charge readout and signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the capacitance of the floating diffusion capacitor is reduced to enhance charge-to-voltage conversion efficiency, then the charge-to-voltage conversion efficiency is improved, but the maximum quantity of charges that can be accumulated in the floating diffusion capacitor is reduced
Solution Approach 1:
The patent divides the charge transfer process into multiple batches. Instead of transferring all charges at once to a single floating diffusion capacitor, the system performs multiple transfer operations where charges are transferred in portions. This segmentation allows the use of capacitors with smaller individual capacitance values (improving charge-to-voltage conversion efficiency) while still being able to handle the total maximum quantity of charges through multiple transfer cycles.
2Use of energy by moving object
If the power source voltage is lowered to reduce power consumption, then power consumption is reduced, but the maximum quantity of charges that can be accumulated in the floating diffusion capacitor is reduced
Solution Approach 1:
The patent segments the charge transfer into multiple batches, allowing the system to operate with lower power source voltage. By transferring charges in multiple smaller batches rather than one large batch, the system can use lower voltage (reducing power consumption) while still accommodating the total charge quantity through repeated transfer operations.
Solution Approach 2:
The patent implements periodic charge transfer operations where charges are transferred in repeated cycles. This periodic action allows the system to maintain lower power source voltage levels while still processing the maximum quantity of charges, as the transfer operation is performed multiple times in sequence rather than requiring high voltage for a single transfer.
3Reliability
If multiple batches of charge transfer are implemented to read out all charges, then all charges can be read out completely, but the complexity of the transfer control system is increased
Solution Approach 1:
The patent employs dynamic control of the transfer transistor based on the accumulated charge quantity in the photoelectric conversion element. The control voltage for the transfer transistor is adjusted dynamically during the multiple batch transfer process, allowing the system to adaptively control the transfer operation. This dynamic control simplifies the overall system architecture by using feedback-based voltage adjustment rather than complex multi-stage transfer control circuits.
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 allows for efficient transfer and processing of signal charges in multiple batches, enhancing charge-to-voltage conversion efficiency and enabling sensitivity adjustments based on light intensity without impairing saturation levels or increasing output rates.
Implementation Method 1
a photoelectric conversion unit configured to convert an optical signal into signal charges
Data Source
AI summary
Disclosed herein is a solid-state imaging device, including, a pixel array unit, first driving means, second driving means, and third driving means.