Image Sensor Waveform Failure Detection via Signal Comparison
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Solution Overview
Problem
Detecting failures in the control circuit of an image sensor is challenging due to the lack of a uniquely determined expected value, making it difficult to implement effective failure detection methods.
Innovation Solution
An imaging device and system that include a pixel array, scanning and readout control sections, and waveform generation parts to generate control signals and reference signals, allowing for failure detection by comparing these signals to identify any discrepancies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If failure detection is implemented for the control circuit, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent creates a copy of the control circuit's waveform generation function by introducing a waveform generation test signal generation unit that replicates the control signal generation logic. This copy operates independently and can be compared with the original control signals to detect failures without adding complex monitoring infrastructure throughout the entire control circuit.
Solution Approach 2:
The patent extracts the waveform generation function from the control circuit and isolates it into a separate test signal generation unit. By taking out this specific function, the patent enables failure detection without requiring monitoring of the entire control circuit, thus reducing the complexity increase that would result from comprehensive monitoring.
2Measurement precision
If waveform generation parts are added for failure detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The waveform generation test signal generation unit serves multiple functions: it generates test signals for failure detection, uses the same waveform generation logic as the control circuit for fair comparison, and can detect various types of failures including timing errors and signal anomalies. This multi-functionality justifies the added complexity by providing comprehensive detection capability.
Solution Approach 2:
The patent changes the parameters of the test signals dynamically by generating waveforms with varying characteristics (different timing, amplitude, and pattern) to comprehensively test the control circuit's functionality. This allows the same test signal generation unit to detect multiple types of failures, improving measurement precision without proportionally increasing complexity.
Data Source
AI summary
An imaging device according to an embodiment of the present disclosure includes a pixel array including a plurality of pixels, a scanning control section that controls scanning of the plurality of pixels, and a readout control section that controls reading of the plurality of pixels. The imaging device further includes a first waveform generation part that generates a plurality of control signals for controlling of at least one of the scanning control section or the readout control section, a second waveform generation part that generates a plurality of reference signals, and a failure detection section that detects a failure of the first waveform generation part or the second waveform generation part on a basis of comparison between the plurality of control signals and the plurality of reference signals.