Image Sensor Pixel Circuit for Integral-Logarithmic Light Adaptation
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Solution Overview
Problem
Image sensors in the related art exhibit limited operating forms in adapting to dynamic environments, particularly when confronted with fluctuations between low and high light scenarios, significantly impacting imaging quality.
Innovation Solution
An image sensor with a pixel array comprising a floating diffusion node, integrating capacitor, photoelectric detection circuit, signal readout circuit, adaptive power supply, and signal processing circuit, allowing for two operating forms: integral and logarithmic, enabling it to adapt to changing light conditions by converting between these forms based on voltage differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the image sensor uses a single operating form (either integral or logarithmic), then the circuit structure can be simplified, but the adaptability to dynamic light environments is limited
Solution Approach 1:
The patent implements a dynamic switching mechanism that allows the image sensor to transition between integral and logarithmic operating forms based on environmental light conditions. The circuit includes switching elements that can connect or disconnect the logarithmic conversion circuitry, enabling the sensor to adapt its operating mode dynamically rather than being fixed in a single state
Solution Approach 2:
The patent designs a universal pixel circuit structure that can perform multiple functions: integral mode for low-light conditions, logarithmic mode for high-dynamic-range conditions, and switching between these modes. The same physical circuit components serve different operational purposes depending on the switching state, achieving multi-functionality without requiring completely separate circuit systems
2Device complexity
If the image sensor operates in integral form only, then the circuit structure is simpler, but the dynamic range in high-light environments is limited
Solution Approach 1:
The patent changes the operational parameters of the pixel circuit by switching between integral and logarithmic conversion modes. The logarithmic mode compresses the output signal range, enabling the circuit to handle high-intensity light without saturation while maintaining detail in both bright and dark regions, thus extending the effective dynamic range
3Illumination intensity
If the image sensor operates in logarithmic form only, then the dynamic range is extended, but the dark light sensitivity is reduced
Solution Approach 1:
The patent dynamically switches between logarithmic and integral modes based on light intensity conditions. The logarithmic mode is activated for high-light scenarios to extend dynamic range, while the integral mode is used for low-light scenarios to maintain dark light sensitivity and measurement precision, achieving context-dependent optimization
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
The image sensor enhances dark light sensitivity and extends dynamic range, improving imaging quality by maintaining low noise in low-light environments and high dynamic range in high-light environments through adaptive operation.
Implementation Method 1
the photoelectric detection circuit is configured to perform a photoelectrical conversion on an incident light to obtain a corresponding photoelectric charge
Data Source
AI summary
Provided are an image sensor and an image output method thereof, and an optoelectronic device. The image sensor includes a plurality of pixels, which include a photoelectric detection circuit, a signal readout circuit, a floating diffusion node, an integrating capacitor, a transmission circuit, an adaptive power supply, and a signal processing circuit. The floating diffusion node integrates the photoelectric charge into the integrating capacitor to obtain an integral voltage. The signal processing circuit generates a logarithmic voltage and a logarithmic current. After the floating diffusion node receives the photoelectric charge, the target voltage is much less than the reference voltage. The node current is the photocurrent, and the node voltage is the integral voltage. When the target voltage increases to the reference voltage, the node current is the logarithmic current, and the node voltage is the logarithmic voltage, so the signal readout circuit finally outputs the corresponding image signals.