Pixel Capacitor Layout for High-Dynamic-Range Image Sensors
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Solution Overview
Problem
Current image sensors face challenges in achieving high dynamic range (HDR) images, which is essential for capturing high-quality images from dark to bright parts, as they struggle to effectively integrate multiple pixels and capacitors with varying capacitances to manage brightness levels efficiently.
Innovation Solution
The proposed image sensor design includes a substrate with multiple pixels, transistors, and capacitors with different capacitances, where the capacitors are strategically placed and structured to store signals from high-brightness and low-brightness operations, allowing for improved HDR properties and increased integration density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple capacitors with different capacitances are integrated into the image sensor to improve HDR capabilities, then the dynamic range and image quality are improved, but the device complexity and integration density challenges increase
Solution Approach 1:
The image sensor divides the pixel array into multiple regions, with different capacitors (first capacitor with first capacitance, second capacitor with second capacitance) placed in different regions. This segmentation allows each capacitor to handle specific brightness ranges, improving HDR capability while managing integration complexity through organized spatial distribution.
Solution Approach 2:
Different capacitors with different capacitance values are strategically placed in different locations within the pixel array. The first capacitor with larger capacitance is positioned to handle low-brightness signals, while the second capacitor with smaller capacitance handles high-brightness signals. This local differentiation optimizes performance for specific signal types without requiring uniform complexity across the entire device.
2Adaptability or versatility
If capacitors with varying capacitances are used to manage brightness levels, then the dynamic range is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs capacitors with different capacitance parameters (first capacitance and second capacitance) to manage different brightness levels. By changing the capacitance parameter rather than using identical capacitors, the system can effectively handle a broader dynamic range. This parameter differentiation is achieved through controlled fabrication processes that create distinct capacitance values in different capacitor regions.
Solution Approach 2:
The patent transitions from a single-capacitor approach to a multi-capacitor system with different capacitance values, adding a dimensional aspect to brightness management. Instead of using one capacitor type, the system utilizes multiple capacitor instances with varying electrical characteristics, effectively adding a new degree of freedom for managing different signal intensities.
3Adaptability or versatility
If the image sensor integrates multiple transistors and capacitors per pixel, then the HDR performance is enhanced, but the area occupied by each pixel increases
Solution Approach 1:
The patent combines multiple functional elements (first transistor, second transistor, first capacitor, second capacitor) within a shared pixel structure. By merging these components and having them work cooperatively, the system achieves enhanced HDR performance while optimizing the use of available pixel area. The combined operation of multiple transistors and capacitors allows for more efficient space utilization compared to redundant separate systems.
Solution Approach 2:
The pixel structure is designed with multi-functional components that serve multiple purposes. The first and second capacitors, along with their associated transistors, work together to handle both low-brightness and high-brightness signals, making the pixel structure universally capable of managing various lighting conditions. This multi-functionality reduces the need for separate dedicated structures for different brightness ranges.
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 design enables the capture of high-quality images with enhanced HDR capabilities by effectively managing brightness levels through capacitors with varying capacitances, thereby improving the overall image sensor performance.
Implementation Method 1
Each of the pixels includes a photodiode (PD). The photodiode is used to convert an incident light to an electric signal.
Data Source
AI summary
An image sensor may include a substrate including pixels, a first transistor and a second transistor disposed on the substrate and spaced apart from each other, a first interlayer insulating layer covering the first transistor and the second transistor, a first lower electrode disposed in the first interlayer insulating layer and connected to an end portion of the first transistor, a first dielectric layer on the first lower electrode, a first upper electrode on the first dielectric layer, a second interlayer insulating layer covering the first upper electrode and the first interlayer insulating layer, and a first pillar provided to penetrate the second and first interlayer insulating layers and connected to an end portion of the second transistor.