ADAS Image Sensor Safety Pixels for Fault Line Detection
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Solution Overview
Problem
Advanced driver assistance systems (ADAS) rely heavily on image sensors for safety functions, but faults in these sensors, such as those caused by cosmic radiation or electromigration, can lead to unreliable operation, necessitating rapid and accurate fault detection to ensure vehicle safety.
Innovation Solution
Incorporating an array of dummy or 'safety' pixels within the image sensor circuitry that provide a specific output signal in the absence of faults, allowing for the detection of issues with control or output lines, thereby indicating potential sensor failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If image sensor reliability is improved through redundant safety pixels, then fault detection capability is enhanced, but device complexity increases
Solution Approach 1:
The image sensor is segmented into functional image pixels and dedicated safety pixels. The safety pixels are further segmented into multiple arrays (first array coupled to first control lines, second array coupled to second control lines) that can independently monitor different portions of the control line network, allowing fault detection without compromising the main imaging function.
Solution Approach 2:
Safety pixels serve as intermediary test elements that indirectly monitor the health of control and output lines. Instead of adding complex test circuitry throughout the sensor, the patent uses these intermediary pixels to detect faults by monitoring whether control signals and output signals are properly transmitted through the line network.
2Measurement precision
If multiple arrays of safety pixels are added to monitor different control lines, then fault detection accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The safety pixels are designed with universal circuitry that can monitor multiple different control lines and output lines. Each safety pixel array can be coupled to different portions of the control line network, allowing the same pixel design to serve multiple monitoring functions across the entire sensor array, simplifying the manufacturing process while maintaining high detection accuracy.
Data Source
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AI summary
An electronic device includes an array of image pixels, with the array of image pixels having inputs coupled to control lines and outputs coupled to output lines, and at least one array of dummy pixels, with the at least one array of dummy pixels having inputs coupled to the control lines. Each dummy pixel of the at least one array of dummy pixels is configured to provide a certain output signal in an absence of a fault with at least one of the control lines or of a fault with at least one of the output lines, such that a lack of output of the certain output signal by one or more of the dummy pixels of the at least one array of dummy pixels indicates the fault.