SPI Slave Image Sensor Pixel Array Circuit Area Reduction
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Solution Overview
Problem
The existing image sensors used in SPI slave circuits require a large storage circuit area for storing pixel values, leading to increased hardware costs.
Innovation Solution
The image sensor incorporates a pixel circuit with multiple storage units, each including a photo sensor, storage switches, and transmission circuits, allowing for serial or parallel connection to store charges accumulated during exposure, reducing the overall circuit area and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large storage circuit is used to store pixel values in the image sensor, then the storage capacity is improved, but the circuit area and hardware cost increase
Solution Approach 1:
The storage circuit is segmented into multiple small storage units distributed across different pixel circuits rather than using a single large centralized storage circuit. Each pixel circuit contains its own storage unit, which stores pixel values locally. This segmentation reduces the area occupied by any single storage component while maintaining the overall storage capacity of the image sensor.
Solution Approach 2:
The patent transitions from a centralized two-dimensional storage architecture to a distributed three-dimensional architecture where storage units are embedded within pixel circuits across multiple layers and dimensions. This dimensional change allows storage capacity to be achieved without proportionally increasing the planar circuit area.
2Quantity of substance
If a large storage circuit is used to store pixel values in the image sensor, then the storage capacity is improved, but the hardware cost increases
Solution Approach 1:
The storage circuit is segmented into multiple small storage units distributed across different pixel circuits rather than using a single large centralized storage circuit. Each pixel circuit contains its own storage unit, which stores pixel values locally. This segmentation reduces the area occupied by any single storage component while maintaining the overall storage capacity of the image sensor.
Solution Approach 2:
The patent employs simple, compact storage units within each pixel circuit that are easier and cheaper to manufacture than a large centralized storage circuit. These distributed storage units use standard pixel circuit components and processes, reducing manufacturing complexity and cost while achieving the required storage capacity.
3Quantity of substance
If multiple storage units are added to each pixel circuit, then the storage capacity is improved, but the device complexity increases
Solution Approach 1:
The storage units within each pixel circuit are designed to perform multiple functions: storing pixel values during exposure, buffering data for sequential readout, and enabling different readout modes (e.g., rolling shutter, global shutter). This multi-functionality increases storage capacity without proportionally increasing complexity, as the same hardware structure serves multiple purposes.
Solution Approach 2:
The patent uses uniform, identical storage unit designs replicated across all pixel circuits. This homogeneity simplifies the overall device complexity by using standardized components and processes throughout the image sensor, making the system easier to manufacture and control despite having multiple storage units distributed across the array.
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 effectively reduces the hardware cost of the image sensor by utilizing smaller analog memory cells for charge storage, enabling efficient storage of multiple images while maintaining operational efficiency.
Implementation Method 1
Each of the pixel units includes a photo sensor... configured to store charges accumulated by the photo sensor
Data Source
AI summary
An image sensor for serial peripheral interface (SPI) slave circuit and a pixel array circuit therein are provided. The pixel array includes a plurality of pixel units disposed in an image sensor with the SPI slave circuit. Each pixel unit includes a photo sensor, N storages and at least one transmission circuit, wherein N is a positive integer greater than or equal to two. At least one of the N storages is coupled to the photo sensor, which are connected with each other in serial or parallel, and configured to store charges accumulated by the photo sensor at different exposures. Each transmission circuit is coupled to a corresponding storage, and is controlled by a corresponding transmission control signal to transmit the stored charge of the corresponding storage during a certain time period.