Image Sensor Clock Signal Propagation for Depth Error Compensation
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Solution Overview
Problem
Large 3D image sensor circuits experience errors in calculating depth due to phase differences generated by clock signals, particularly in pixel arrays with many pixels, which affect the accuracy of distance calculations.
Innovation Solution
An image sensor circuit design that uses clock signals propagated in opposite directions within a pixel series, with a clock signal generating circuit connected to both ends of the pixel series, allowing phase differences at one time to compensate for those at another time, reducing overall error in depth calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large pixel array is used to improve depth measurement coverage, then the measurement area is increased, but phase differences in clock signals cause errors in depth calculation
Solution Approach 1:
The pixel array is divided into multiple pixel series, with each series independently clocked from both ends. This segmentation allows clock signals to be distributed in opposite directions through buffer modules, reducing cumulative phase differences across the large array while maintaining comprehensive coverage.
Solution Approach 2:
Clock signals are propagated in opposite directions from both ends of each pixel series rather than from a single end. This inverted approach causes phase differences to compensate each other, with earlier clocked pixels in one direction being later in the opposite direction, thereby reducing overall measurement errors.
2Measurement precision
If clock signals are propagated in opposite directions from both ends of pixel series, then phase difference influence is reduced, but device complexity increases
Solution Approach 1:
The clock signal generating circuit is segmented into multiple buffer modules, each responsible for a specific pixel series. This modular segmentation manages complexity by distributing the clocking function across independent units rather than requiring a single complex centralized controller.
Solution Approach 2:
The same buffer module design is copied and replicated for each pixel series. This standardization reduces overall system complexity by using identical, well-understood circuit blocks rather than designing unique complex circuitry for each series.
Data Source
AI summary
The present disclosure provides an image sensor circuit, including: a pixel array, including a plurality of pixel series, where a pixel series in the plurality of pixel series includes a plurality of pixel circuits; and a clock signal generating circuit, coupled to a first end and a second end of the pixel series; where a first clock signal is propagated from the first end of the pixel series to the second end of the pixel series at a first time; and where a second clock signal is propagated from the second end of the pixel series to the first end of the pixel series.