Image Sensor Pixel Segmentation for TOF Interference Reduction
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Solution Overview
Problem
Current image sensors face challenges in miniaturization while maintaining performance, particularly in Time of Flight (TOF) methods used for distance measurement, due to mutual interference between pixel transistor regions which can lead to decreased throughput and pixel deterioration.
Innovation Solution
The image sensor design includes a detection region with first and second demodulation nodes generating electrical currents, and first and second pixel transistor regions disposed on opposite sides of the detection region to minimize interference and prevent performance deterioration during size reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If pixel size is reduced for miniaturization, then device compactness is improved, but mutual interference between transistor regions increases causing performance deterioration
Solution Approach 1:
The pixel structure is divided into separate first and second transistor regions that are spatially separated and independently configured. This segmentation allows each transistor region to operate with reduced mutual interference even when the overall pixel size is minimized, thereby maintaining pixel performance during miniaturization.
Solution Approach 2:
The patent utilizes three-dimensional substrate structure with wells formed at different depths (first well and second well in the substrate). By arranging transistor regions in different spatial dimensions and depths, the design achieves compact two-dimensional footprint while maintaining three-dimensional separation to reduce interference between components.
2Volume of moving object
If pixel size is reduced for miniaturization, then manufacturing cost is reduced, but throughput decreases due to increased interference
Solution Approach 1:
By segmenting the pixel into distinct first and second transistor regions with separate photodiode structures, the design enables efficient parallel operation of multiple photodiodes within each region. This segmentation maintains high throughput by allowing simultaneous charge generation and processing in separated zones, even when miniaturized.
Solution Approach 2:
The patent employs dual-wavelength operation with different photodiode structures (first photodiode and second photodiode) that can detect different wavelengths of light. This parameter change enables multiplexed signal processing and maintains high throughput by utilizing multiple detection channels within the miniaturized pixel structure.
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 allows for effective miniaturization of image sensors without compromising performance, reducing mutual interference and maintaining pixel efficiency even with reduced pixel size.
Implementation Method 1
detection region including a first demodulation node and a second demodulation node, and configured to generate an electrical current in a substrate and capture photocharges that are generated by incident light
Data Source
AI summary
An image sensor includes a detection region, a first transistor region, and a second transistor region. The detection region including a first demodulation node and a second demodulation node generates a hole current in a substrate, and captures photocharges that are generated by incident light and move by the hole current. The first pixel transistor region including a plurality of transistors is disposed at one side of the detection region, and processes photocharges captured by the first demodulation node. The second pixel transistor region including a plurality of transistors is disposed at other side of the detection region, and processes photocharges captured by the second demodulation node.