Segmented Electroconductive Member for Imaging Device Resistance Control
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Solution Overview
Problem
The variability in electric resistance of the electroconductive member in solid state imaging devices poses challenges to ensuring stability and consistent operation, as it affects charge readout speed and heat generation, leading to dispersion issues.
Innovation Solution
The electroconductive member is designed with alternating regions of different electric resistivities, where the second region has a lower resistivity than the first, allowing for a combined resistance that stabilizes the device's operation without increasing dispersion, and is composed of polysilicon doped with varying impurity concentrations to maintain uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electric resistance of the electroconductive member is set low to achieve sufficient readout speed, then charge readout speed is improved, but heat generation increases causing dark current increase
Solution Approach 1:
The electroconductive member is divided into multiple regions with different electric resistances. Specifically, it includes a first region with higher resistance and a second region with lower resistance, allowing different portions to serve different functions in the charge transfer process
Solution Approach 2:
Different regions of the electroconductive member are assigned different resistance characteristics tailored to their specific functions. The first region with higher resistance suppresses dark current, while the second region with lower resistance enables fast charge transfer, optimizing local performance for each functional requirement
2Object-generated harmful factors
If the electric resistance of the electroconductive member is set high to suppress heat generation and dark current, then dark current is reduced, but charge readout speed decreases
Solution Approach 1:
The electroconductive member is divided into multiple regions with different electric resistances. Specifically, it includes a first region with higher resistance and a second region with lower resistance, allowing different portions to serve different functions in the charge transfer process
Solution Approach 2:
Different regions of the electroconductive member are assigned different resistance characteristics tailored to their specific functions. The first region with higher resistance suppresses dark current, while the second region with lower resistance enables fast charge transfer, optimizing local performance for each functional requirement
3Manufacturing precision
If the electric resistivity of the electroconductive member is set to reduce dispersion, then manufacturing consistency is improved, but operation stability may be compromised
Solution Approach 1:
The electroconductive member is segmented into regions with different resistance values, where each region can be independently optimized. This allows the overall system to achieve both low dispersion through controlled fabrication of individual regions and proper operational characteristics through the combined effect of the segmented structure
Solution Approach 2:
The electroconductive member uses a composite structure with regions of different resistivity, combining the advantages of both high-resistance (low dark current) and low-resistance (fast transfer) materials in a single integrated component
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 reduces dispersion in electric resistance, ensuring stable operation and characteristics by maintaining uniform charge readout speed and heat generation across the device, thereby enhancing the reliability of the solid state imaging device.
Implementation Method 1
the electroconductive member includes a first region having a first electric resistivity and a second region having a second electric resistivity smaller than the first electric resistivity
Implementation Method 2
a photoelectric conversion portion having a plurality of photosensitive regions to generate respective charges according to incidence of light
Data Source
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AI summary
A solid state imaging device 1 is provided with a photoelectric conversion portion 2 having a plurality of photosensitive regions 7, and a potential gradient forming portion 3 having an electroconductive member 8 arranged opposite to the photosensitive regions 7. A planar shape of each photosensitive region 7 is a substantially rectangular shape. The photosensitive regions 7 are juxtaposed in a first direction intersecting with the long sides. The potential gradient forming portion 3 forms a potential gradient becoming higher along a second direction from one of the short sides to the other of the short sides of the photosensitive regions 7. The electroconductive member 8 includes a first region 8a extending in the second direction and having a first electric resistivity, and a second region 8b extending in the second direction and having a second electric resistivity smaller than the first electric resistivity.