Stacked Image Sensor Layout for PDAF and Event Signal Processing
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Solution Overview
Problem
Current image sensors face challenges in efficiently processing large amounts of data from CMOS image sensors while also requiring phase detection for auto-focus and event detection from dynamic vision sensors, leading to increased complexity and resource utilization.
Innovation Solution
An image sensor design that incorporates a semiconductor die with a pixel array featuring both phase detection and dynamic vision sensor pixels, along with separate logic circuits and an image signal processor to manage and process signals from these components, optimizing the sensor's structure and resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CMOS image sensor and dynamic vision sensor are implemented as one image sensor, then various functions (de-blur, super slow, PDAF) are supported, but the amount of data to be processed increases and device complexity increases
Solution Approach 1:
The image sensor is divided into distinct functional modules: a pixel array unit containing both CMOS and DVS pixels, a signal processing unit with separate processing circuits for each sensor type, and an image signal processor. This segmentation allows each module to handle specific tasks independently, reducing overall system complexity while maintaining multi-functionality.
Solution Approach 2:
The patent transitions from a two-dimensional planar integration of pixels to a three-dimensional stacked architecture where the pixel array unit is vertically separated from the signal processing unit. This vertical dimensionality change allows independent optimization of each layer, reducing interference between different sensor types and simplifying signal routing.
2Adaptability or versatility
If CMOS image sensor and dynamic vision sensor are implemented as one image sensor, then various functions (de-blur, super slow, PDAF) are supported, but the amount of data to be processed increases
Solution Approach 1:
The signal processing unit contains separate processing circuits: a first processing circuit dedicated to CMOS sensor data and a second processing circuit dedicated to DVS sensor data. This segmentation enables parallel processing of different data types, improving overall data processing efficiency while supporting multiple functions simultaneously.
Solution Approach 2:
An image signal processor acts as an intermediary between the pixel array unit and the external system. It consolidates and pre-processes data from both CMOS and DVS sensors before output, reducing the burden on external processors and improving overall system productivity.
3Adaptability or versatility
If phase detection pixels are discontinuously or regularly disposed within pixel array, then PDAF function is achieved, but device complexity increases
Solution Approach 1:
Phase detection pixels are integrated within the regular pixel array structure rather than being separately disposed. The pixel array unit contains a mixture of CMOS pixels and phase detection pixels in a unified grid, simplifying the overall array structure while maintaining PDAF functionality through the combined signal from both pixel types.
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 data processing efficiency by separating the CMOS and DVS pixel circuits, allowing for effective phase detection auto-focus and event detection, while reducing the burden on the image signal processor and optimizing the sensor's size and functionality.
Implementation Method 1
first and second photoelectric conversion devices configured to generate respective charges corresponding to incident light
Data Source
AI summary
An embodiment of the present disclosure provides an image sensor including: a first die including a pixel array area in which first and second photoelectric conversion devices that generate respective charges corresponding to incident light are disposed; and a second die including a first pixel circuit that receives the charges from the first photoelectric conversion device and generates a phase signal of the incident light based on the charges received from the first photoelectric conversion device, and a second pixel circuit that receives the charges from the second photoelectric conversion device and generates an event signal corresponding to the incident light based on the charges received from the second photoelectric conversion device.