Stacked Pixel Circuit Layout for Better Signal Detection
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Solution Overview
Problem
Current imaging devices face limitations in the degree of freedom of element layout, which restricts the optimization of pixel and circuit configurations, leading to suboptimal performance in signal detection and noise reduction.
Innovation Solution
The proposed imaging device employs a stacked substrate configuration with a first substrate containing a photoelectric converter and detection circuit, and a second substrate with a constant current source and bias circuit, allowing for enhanced signal amplification and noise reduction through strategic connection of transistors and capacitors, and flexible operation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If elements are arranged on a single substrate, then the structure is simple, but the degree of freedom of element layout is limited
Solution Approach 1:
The imaging device divides the substrate into multiple separate substrates (first substrate for photoelectric converters, second substrate for detection circuits, third substrate for voltage sources). This segmentation allows each substrate to be optimized independently for its specific function, thereby enhancing the degree of freedom in element layout while managing device complexity through modular design
Solution Approach 2:
The patent transitions from a two-dimensional planar layout on a single substrate to a three-dimensional stacked configuration with multiple substrates arranged vertically. This dimensional change enables independent optimization of each substrate's element layout without being constrained by planar space, thus improving layout freedom while organizing complexity in the vertical dimension
2Adaptability or versatility
If photoelectric converters and detection circuits are integrated on the same substrate, then the connection is direct, but the degree of freedom of element layout is limited
Solution Approach 1:
The imaging device separates photoelectric converters onto a first substrate and detection circuits onto a second substrate, with voltage sources on a third substrate. This segmentation allows each component to be independently optimized for its specific function while maintaining reliable connections through vertical stacking, thereby improving both layout flexibility and signal detection performance
Solution Approach 2:
The patent introduces intermediate connection structures (connection portions between substrates) that mediate the interaction between photoelectric converters and detection circuits. These intermediaries enable flexible routing of signal charges while maintaining reliable electrical connections, resolving the contradiction between layout freedom and detection reliability
3Adaptability or versatility
If voltage sources are placed close to detection circuits, then the connection is short, but the degree of freedom of element layout is reduced
Solution Approach 1:
The patent places voltage sources on a third substrate stacked vertically above or below the second substrate containing detection circuits. This vertical arrangement in three-dimensional space maintains short electrical connection paths while freeing up horizontal layout space, thereby achieving both layout freedom and minimal connection length
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 enhances the degree of freedom in element layout, improving signal detection and reducing noise, particularly reset noise, while allowing for efficient signal processing and data acquisition.
Implementation Method 1
a photoelectric converter that converts incident light into a signal charge
Data Source
AI summary
An imaging device includes a first substrate, and a second substrate stacked on the first substrate. A first connection portion and a second connection portion are between the first substrate and the second substrate. A first pixel and a second pixel each include a photoelectric converter that converts incident light into a signal charge, and a detection circuit that detects the signal charge. The first substrate includes the photoelectric converter and the detection circuit. The second substrate includes a first line, and a voltage source that is coupled to the detection circuit of the first pixel, via the first line and the first connection portion, and that is coupled to the detection circuit of the second pixel, via the first line and the second connection portion.