Imaging Sensor Parallel Wiring Reduces Resistance
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Solution Overview
Problem
In imaging devices with CMOS sensors, the long wiring distances within the solid state image sensor lead to increased wiring resistance, causing significant voltage drops and image quality issues such as smear and level differences in A/D conversion, particularly in full-size CMOS sensors where miniaturization limits wiring width and thickness.
Innovation Solution
The implementation of a parallel wiring configuration within a storage package, where the internal wiring of the solid state image sensor is connected to external wiring between layers of the package, reducing overall resistance by forming a parallel circuit with the internal wiring and external package wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power supply circuit is configured inside of a solid state image sensor, then the power supply can be provided to circuits disposed for respective columns, but the wiring resistance increases due to long wiring distance in column direction
Solution Approach 1:
The patent introduces a ground wiring that extends in the row direction (horizontal dimension) to connect ground terminals of amplification transistors across different columns, rather than relying solely on vertical column-direction wiring. This dimensional change creates alternative current paths that reduce the effective resistance in the column direction by providing parallel conduction paths through the row-direction ground wiring.
2Loss of energy
If the wiring width and thickness are increased to reduce wiring resistance, then the wiring resistance decreases, but the area of the solid state image sensor increases
Solution Approach 1:
The patent merges the ground wiring function with existing signal wiring structures by using the same wiring layers and routing paths for multiple functions. The ground wiring is integrated into the existing wiring architecture, sharing wiring layers and spatial resources with signal paths, thereby reducing resistance without requiring additional dedicated wiring area.
Solution Approach 2:
The wiring structure serves multiple functions simultaneously: it provides ground references for amplification transistors, establishes return paths for signal currents, and creates parallel conduction paths to reduce resistance. This multi-functionality allows a single wiring structure to address multiple requirements without proportionally increasing the total wiring area.
3Loss of energy
If the wiring distance is reduced, then the wiring resistance decreases, but the layout flexibility of the pixel array is reduced
Solution Approach 1:
The ground wiring is segmented into multiple sections that are distributed across different rows and columns, with each segment serving local amplification transistors. These segmented ground paths are interconnected through vertical and horizontal wiring segments, creating a distributed network that reduces effective resistance while maintaining layout flexibility through modular configuration.
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 significantly reduces wiring resistance, minimizing voltage drops and preventing image quality deterioration like smear and level differences, thereby enhancing the imaging performance by maintaining consistent signal levels across columns.
Implementation Method 1
having a second wiring configuring a parallel circuit by being connected to the first wiring
Data Source
AI summary
An image sensor having a pixel part generating a signal in accordance with a light, a signal processing part performing signal processing on the signal read from the pixel part, and a power supply part connected to the signal processing part via a first wiring, and supplying a power supply to the signal processing part, and a storage package storing the image sensor, and having a second wiring configuring a parallel circuit by being connected to the first wiring. Accordingly, it is possible to solve a problem such that a wiring resistance is increased when a power supply circuit is configured inside of a solid state image sensor.