Image Sensor Unit Pixels with Shared Floating Diffusion Regions
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Solution Overview
Problem
Current image sensors face challenges in achieving high integration density and effectively realizing three-dimensional images, particularly in applications requiring precise depth sensing and color imaging.
Innovation Solution
The design incorporates unit pixels with first and second floating diffusion regions and photo gate electrodes arranged in specific configurations, allowing for improved light sensing and depth calculation by utilizing pulsed optical signals and phase-difference photo control signals to determine optical depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional image sensor designs are used, then manufacturing is simpler, but integration density is lower
Solution Approach 1:
The pixel structure is divided into multiple functional regions including first and second photo gate electrodes, first and second floating diffusion regions, and shared readout circuits. This segmentation allows independent optimization of each region while achieving high integration density through systematic arrangement.
Solution Approach 2:
Adjacent pixels share common readout circuits and control structures, allowing a single circuit to serve multiple pixels. This multi-functionality reduces the overall circuit count and increases integration density without compromising pixel performance.
2Measurement precision
If more photo gates and floating diffusion regions are added for depth sensing, then depth measurement accuracy improves, but device complexity increases
Solution Approach 1:
Multiple photo gates and floating diffusion regions are combined within a compact pixel structure. The first and second photo gates work together with their respective floating diffusion regions to enable both color imaging and depth sensing functions simultaneously.
Solution Approach 2:
The patent utilizes phase-difference photo control signals in the time domain to achieve depth sensing. By modulating photo gates with phase-different signals and measuring temporal differences in charge transfer, depth information is extracted without adding significant spatial complexity.
3Quantity of substance
If floating diffusion regions are positioned between photo gate electrodes of adjacent pixels, then integration density increases, but manufacturing precision requirements increase
Solution Approach 1:
The floating diffusion regions are strategically positioned in specific locations between adjacent pixels where they can serve multiple functions. Each floating diffusion region is locally optimized to act as both a charge storage node for its own pixel and a shared element for adjacent pixels, reducing overall complexity.
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 image sensor's ability to capture three-dimensional images with increased integration density, improving sensitivity and accuracy in depth measurement and color imaging applications.
Implementation Method 1
Each of the plurality of unit pixels may include first and second floating diffusion regions and first and second photo gate electrodes between the first and second floating diffusion regions
Data Source
AI summary
Image sensors are provided. Image sensors may include unit pixels arranged in a first direction and a second direction crossing the first direction. Each of the unit pixels may include first and second floating diffusion regions and first and second photo gate electrodes between the first and second floating diffusion regions. The unit pixels may include a first unit pixel, a second unit pixel, and a third unit pixel sequentially arranged. The first floating diffusion region of the second unit pixel may be between the first photo gate electrode of the first unit pixel and the first photo gate electrode of the second unit pixel, and the second floating diffusion region of the second unit pixel may be between the second photo gate electrode of the second unit pixel and the second photo gate electrode of the third unit pixel.