Solid-State Image Sensor Pixel Linking for Dynamic Range and SN Ratio
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid-state image sensors have limitations in expanding their dynamic range and signal-to-noise (SN) ratio, especially for high-sensitivity reads, due to constraints in charge/voltage conversion capacitance and linking switch configurations.
Innovation Solution
The implementation of a solid-state image sensor design with a connection unit comprising multiple linking units and switches between charge accumulating units of adjacent pixels, allowing for controlled electrical connections and disconnections to optimize capacitance and SN ratio through various operation modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the linking switch is turned on to connect charge/voltage conversion capacitances, then the dynamic range is expanded, but the capacitance of the charge/voltage conversion region increases which limits the SN ratio improvement
Solution Approach 1:
The patent divides the charge accumulating units into multiple segments (first charge accumulating unit and second charge accumulating unit) within each pixel. These segments can be independently controlled through separate linking switches, allowing the system to selectively connect or disconnect capacitances to optimize both dynamic range and SN ratio for different reading scenarios.
Solution Approach 2:
The patent implements dynamic control of the linking switches that connect charge accumulating units. The switches can be turned on or off based on the required operation mode (high-sensitivity read or standard read), enabling the system to dynamically adjust the total capacitance value. This dynamic adjustment allows the system to achieve both high dynamic range (when switches are on) and high SN ratio (when switches are off) as needed.
2Measurement precision
If the linking switch is turned off to separate charge/voltage conversion regions, then the charge/voltage conversion capacitance is reduced improving SN ratio, but the dynamic range expansion is limited
Solution Approach 1:
The patent designs the pixel structure with multiple charge accumulating units and linking switches that can serve multiple functions. The same hardware configuration supports both high-sensitivity reading mode (with lower capacitance for higher SN ratio) and standard reading mode (with higher capacitance for greater dynamic range), making the system universally applicable to different imaging scenarios without requiring separate hardware for each mode.
3Quantity of substance
If multiple charge accumulating units are connected in parallel, then the saturation electron capacity increases, but the charge/voltage conversion coefficient decreases
Solution Approach 1:
The patent uses controllable linking switches to dynamically adjust the parallel connection status of multiple charge accumulating units. When high saturation electron capacity is needed, the switches connect the units in parallel, increasing total capacitance. When high charge/voltage conversion coefficient is needed, the switches disconnect the units, reducing total capacitance and increasing the conversion coefficient. This dynamic reconfiguration resolves the contradiction between capacity and conversion efficiency.
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 enhances the dynamic range and SN ratio for high-sensitivity reads by adjusting capacitance values and charge accumulation, enabling better signal handling and expanded saturation electron capacity.
Implementation Method 1
a photoelectric conversion unit and a charge accumulating unit that accumulates an electric charge from the photoelectric conversion unit
Data Source
AI summary
An image sensor includes a plurality of pixel blocks and a connection unit. The plurality of pixel blocks includes: a diffusion unit to which an electric charge resulting from photoelectric conversion is transferred; and a transistor containing a source electrically connected with the diffusion unit. The connection unit is electrically connected with a drain of the transistor included in each of the plurality of pixel blocks.