Imaging Element Charge Storage for Accurate Distance Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor detecting elements using the Time of Flight method face challenges in accurately reading out signal differences between Floating Diffusions with different capacitances, leading to inaccurate distance measurements.
Innovation Solution
The implementation of a structure with multiple charge storage sections, each provided between a first gate of a transistor and a second gate or a trench, ensures equal capacitance across the Floating Diffusions, enabling accurate signal reading and improved distance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If signal charge is distributed to two FDs by a pair of gate electrodes alternately driven, then distance measurement function is achieved, but measurement precision deteriorates when FDs have different capacitances
Solution Approach 1:
The patent applies parameter changes by modifying the capacitance values of the Floating Diffusion regions. Specifically, it introduces a capacitance adjustment structure that adds different capacitance values to different FDs, thereby equalizing their total capacitances. This parameter adjustment resolves the contradiction by making the capacitance a controllable variable rather than a fixed parameter, allowing the system to achieve both reliable signal reading and accurate distance measurement.
2Measurement precision
If two FDs have different capacitances, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent introduces an intermediary capacitance adjustment structure that mediates between the two Floating Diffusion regions. This intermediary structure acts as a buffer or equalizer, adding the necessary capacitance to balance the FDs without requiring complete redesign of the entire pixel structure. The intermediary capacitance structure serves as a bridge that resolves the contradiction by providing a controlled way to equalize capacitances while minimizing overall 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
This configuration ensures accurate and consistent signal reading across Floating Diffusions, enhancing the precision of distance measurements in semiconductor detecting elements.
Implementation Method 1
a photodiode... Signal charge generated by the photoelectric conversion
Data Source
AI summary
An imaging element includes a photoelectric converting section configured to perform photoelectric conversion, a plurality of charge storage sections configured to store charge obtained by the photoelectric converting section, and a plurality of transfer sections configured to transfer the charge from the photoelectric converting section to each of the plurality of charge storage sections. Each of the charge storage sections is provided between a first gate of a transistor included in a corresponding one of the transfer sections and a second gate provided at a position parallel to the first gate.