Image Sensor Parallel Readout Circuit Architecture
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Solution Overview
Problem
Existing image sensors face challenges in increasing readout speed for low-resolution modes and reducing the processing load on circuits, particularly when capturing moving images, as they do not efficiently parallelize the readout of low-resolution pixel signals through multiple channels.
Innovation Solution
The image sensor employs a plurality of readout circuits, output channels, and column selecting switches controlled by a circuit to output pixel signals in a spatial order, with optional averaging or summing circuits to generate signals for low-resolution readout, allowing parallel readout of pixel signals through multiple channels, thereby increasing frame rate and reducing processing load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pixel signals are parallely read out through multiple channels in low-resolution mode, then readout speed increases, but processing circuit load increases due to signal rearrangement requirements
Solution Approach 1:
The pixel array is divided into multiple independent readout regions, each with its own readout circuit. Multiple readout circuits operate in parallel to simultaneously read out pixel signals from different regions through separate output channels, achieving high-speed parallel readout without requiring signal rearrangement in the processing circuit.
Solution Approach 2:
The patent introduces a spatial dimension to the readout architecture by dividing the pixel array into multiple regions that can be read out simultaneously through different output channels. This multi-dimensional parallel readout approach allows low-resolution pixel signals to be read out through multiple channels without requiring temporal or spatial rearrangement in the processing circuit.
2Productivity
If multiple readout circuits are used for parallel readout, then frame rate increases, but circuit arrangement complexity increases
Solution Approach 1:
The patent extracts and removes unnecessary signal rearrangement functions from the processing circuit by designing the readout system to naturally output signals in the correct spatial order. Multiple readout circuits directly output signals through separate channels without requiring subsequent rearrangement, simplifying the processing circuit architecture.
Solution Approach 2:
Each readout circuit is designed with universal functionality to handle multiple operations including signal amplification, selection, and direct output through separate channels. This multi-functional design allows the system to achieve high frame rates while maintaining simplified circuit arrangement, as each readout circuit independently manages its signal path without requiring complex inter-circuit coordination.
Data Source
AI summary
An image sensor has a plurality of pixels arrayed to form a plurality of columns. The sensor includes a plurality of readout circuits which generate pixel signals based on signals supplied from the pixels of respective columns, a plurality of output channels, a plurality of column selecting switches, and a control circuit which controls the plurality of column selecting switches. The control circuit controls the plurality of column selecting switches so as to output the pixel signals of target readout pixels to output channels selected based on a selection rule in the spatial order of the pixels in the full pixel readout mode. The control circuit controls the plurality of column selecting switches so as to output the thinned-out pixel signals of target readout areas to output channels selected based on the same rule as the selection rule in the spatial order of the areas in the thinning readout mode.