Solid-State Imaging Device Chip Segmentation for Noise Reduction
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Solution Overview
Problem
Conventional Dynamic Vision Sensors (DVS) suffer from noise characteristic deterioration due to dark current flowing from photoelectric conversion elements into pixel circuits, integrated on the same substrate, leading to reduced light reception efficiency and transistor noise issues.
Innovation Solution
A solid-state imaging device with photoelectric conversion elements and detection units on separate chips, reducing dark current ingress and improving noise characteristics by separating the light reception and pixel circuit components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If photoelectric conversion elements and pixel circuits are integrated on the same substrate, then device complexity is reduced and manufacturing is simplified, but dark current flows from the photoelectric conversion element into the pixel circuit causing noise characteristic deterioration
Solution Approach 1:
The patent divides the imaging device into two separate chips: a first chip containing photoelectric conversion elements and a second chip containing pixel circuits. This segmentation physically isolates the photoelectric conversion elements from the pixel circuits, preventing dark current from flowing into the pixel circuit and degrading noise characteristics, while still maintaining functional integration through chip-to-chip connection.
Solution Approach 2:
The patent extracts the pixel circuit from the same substrate as the photoelectric conversion element and places it on a separate chip. This extraction removes the harmful interaction where dark current from the photoelectric conversion element would flow into the pixel circuit, thereby eliminating the noise characteristic deterioration while preserving the functional relationship between the two components.
2Manufacturing precision
If photoelectric conversion elements and pixel circuits are integrated on the same substrate, then manufacturing precision requirements are reduced, but light reception efficiency decreases due to dark current interference
Solution Approach 1:
By segmenting the device into separate chips for photoelectric conversion and pixel circuit processing, the patent eliminates dark current interference that would otherwise reduce light reception efficiency. The physical separation ensures that the photoelectric conversion elements can operate with high efficiency without being affected by dark current flowing into adjacent pixel circuits.
3Device complexity
If photoelectric conversion elements and pixel circuits are integrated on the same substrate, then device structure is simplified, but transistor noise increases due to dark current flow
Solution Approach 1:
The patent segments the device architecture into two separate chips, placing photoelectric conversion elements on the first chip and pixel circuits on the second chip. This segmentation prevents dark current generated by the photoelectric conversion elements from flowing into the transistors of the pixel circuits, thereby eliminating the source of transistor noise while maintaining functional integration through controlled connections between chips.
Solution Approach 2:
The patent extracts the pixel circuit from the photoelectric conversion element substrate and places it on a separate chip. This extraction removes the harmful pathway for dark current to reach the transistor, eliminating transistor noise generation while preserving the necessary functional relationship between light reception and signal processing components.
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
Enhances noise characteristics and light reception efficiency by isolating photoelectric conversion elements from pixel circuits, thereby reducing transistor noise and improving overall imaging performance.
Implementation Method 1
a plurality of photoelectric conversion elements arranged in a two-dimensional grid shape in a matrix direction and each generating a charge corresponding to a received light amount
Data Source
AI summary
Improvement of noise characteristics is achievable. A solid-state imaging device according to an embodiment includes a plurality of photoelectric conversion elements (333) arranged in a two-dimensional grid shape in a matrix direction and each generating a charge corresponding to a received light amount, and a detection unit (400) that detects a photocurrent produced by the charge generated in each of the plurality of photoelectric conversion elements. A chip (201a) on which the photoelectric conversion elements are disposed and a chip (201b) on which at least a part of the detection unit is disposed are different from each other.