Shared-Photodetector Pixel Circuit for Intensity and Contrast Detection
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Solution Overview
Problem
Current imaging systems face challenges in simultaneously detecting illumination intensity and contrast changes effectively, particularly in modes that require exclusive operation of pixels for either intensity or contrast detection.
Innovation Solution
The implementation of an imaging sensor with a shared photodetector and two transfer transistors, allowing for mutually exclusive operational modes for intensity detection and contrast change detection, utilizing a 4T pixel configuration for standard operation and enabling full charge transfer and photodiode depletion for intensity detection, while allowing photoelectrons to flow through for contrast change detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pixels operate in frame-based camera mode for illumination intensity detection, then full charge transfer and photodiode depletion are enabled for accurate intensity measurement, but the pixels cannot simultaneously perform contrast change detection
Solution Approach 1:
The pixel circuit dynamically switches between two operational modes using two transfer transistors. The first transfer transistor enables full charge transfer to the floating diffusion for illumination intensity detection in frame-based camera mode. The second transfer transistor enables contrast change detection by allowing photoelectrons to flow through the photodiode without full charge transfer. This dynamic switching mechanism allows the same hardware to adapt to different detection requirements.
Solution Approach 2:
The imaging sensor achieves multi-functionality by integrating two transfer transistors in each pixel circuit. This universal design allows the pixel to perform both illumination intensity detection (frame-based camera mode) and contrast change detection (dynamic vision sensor mode) using the same photodetector and readout circuitry, eliminating the need for separate sensor arrays for different detection modes.
2Adaptability or versatility
If pixels operate in dynamic vision sensor mode for contrast change detection, then photoelectrons can flow through for real-time contrast detection, but full charge transfer and photodiode depletion cannot be achieved for illumination intensity detection
Solution Approach 1:
The pixel circuit dynamically switches between two operational modes using two transfer transistors. The first transfer transistor enables full charge transfer to the floating diffusion for illumination intensity detection in frame-based camera mode. The second transfer transistor enables contrast change detection by allowing photoelectrons to flow through the photodiode without full charge transfer. This dynamic switching mechanism allows the same hardware to adapt to different detection requirements.
Solution Approach 2:
The imaging sensor achieves multi-functionality by integrating two transfer transistors in each pixel circuit. This universal design allows the pixel to perform both illumination intensity detection (frame-based camera mode) and contrast change detection (dynamic vision sensor mode) using the same photodetector and readout circuitry, eliminating the need for separate sensor arrays for different detection modes.
3Reliability
If separate pixel circuits are used for intensity detection and contrast change detection, then each mode can be optimized independently, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the functionality of separate intensity detection pixels and contrast change detection pixels into a single unified pixel circuit. By combining two transfer transistors within one pixel, the design achieves both detection modes in a single integrated structure, reducing overall device complexity while maintaining mode-specific optimization capabilities.
Solution Approach 2:
The imaging sensor achieves multi-functionality by integrating two transfer transistors in each pixel circuit. This universal design allows the pixel to perform both illumination intensity detection (frame-based camera mode) and contrast change detection (dynamic vision sensor mode) using the same photodetector and readout circuitry, eliminating the need for separate sensor arrays for different detection modes.
4Ease of manufacture
If a standard 4T pixel configuration is used, then manufacturing is simplified and production cost is reduced, but the pixel cannot perform both intensity detection and contrast change detection
Solution Approach 1:
The imaging sensor achieves multi-functionality by integrating two transfer transistors in each pixel circuit. This universal design allows the pixel to perform both illumination intensity detection (frame-based camera mode) and contrast change detection (dynamic vision sensor mode) using the same photodetector and readout circuitry, eliminating the need for separate sensor arrays for different detection modes.
Solution Approach 2:
The patent merges the functionality of separate intensity detection pixels and contrast change detection pixels into a single unified pixel circuit. By combining two transfer transistors within one pixel, the design achieves both detection modes in a single integrated structure, reducing overall device complexity while maintaining mode-specific optimization capabilities.
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
Enables efficient detection of illumination intensity and contrast changes, allowing the imaging sensor to operate in both frame-based camera mode and dynamic vision sensor mode, improving the system's adaptability and accuracy in various lighting conditions.
Implementation Method 1
a plurality of photodetectors configured to receive light from a physical environment
Data Source
AI summary
Various implementations disclosed herein include devices, systems, and methods implemented by an electronic device with an imaging sensor including a plurality of pixels (e.g., a matrix of pixels) that each are capable of detecting illumination intensity or contrast change using at least one shared photosensor. In some implementations, the imaging sensor is capable of operating in a first illumination intensity detecting mode (e.g., in a frame-based camera mode) or in a second contrast change detecting mode (e.g., in an event camera mode). In some implementations, the first illumination intensity detecting mode and the second contrast change detecting mode are mutually exclusive. In some implementations, pixels at an imaging sensor include two transfer transistors (e.g., gates) where a first transfer transistor allows intensity detection, and a second transfer transistor allows contrast change detection.