Stacked Image Sensor Failure Detection Through Row Timing Comparison
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Solution Overview
Problem
Existing imaging devices with stacked substrates are unable to detect failures effectively, which can lead to erroneous detection and inadequate driving support, posing a safety risk.
Innovation Solution
A two-layer structure is implemented, where the upper chip contains a pixel array and the lower chip includes signal processing units, connected via through-chip vias, enabling failure detection through row and pulse output failure detection processes, as well as ADC+TCV failure detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a plurality of substrates are stacked to reduce device size, then miniaturization is achieved, but failure detection capability is lost
Solution Approach 1:
The imaging device is segmented into multiple functional substrates (first substrate with pixel array, second substrate with signal processing circuits, third substrate with failure detection circuits). This segmentation allows each substrate to have specialized functions, including dedicated failure detection capabilities that work specifically for the stacked structure without interfering with miniaturization goals.
Solution Approach 2:
Failure detection circuits and test signal lines are built into the device structure during manufacturing, before actual operation. Test signals are preliminarily configured to flow through vertical signal lines connecting substrates, enabling proactive failure detection rather than waiting for operational failures to manifest.
2Measurement precision
If conventional failure detection techniques are used, then horizontal signal line disconnection can be detected, but failures in stacked substrate structures cannot be detected
Solution Approach 1:
The failure detection system is designed with universal applicability to stacked substrate architectures. The detection circuits can handle both horizontal signal lines within a substrate and vertical signal lines between substrates, making the system versatile for multi-substrate configurations while maintaining detection precision.
Solution Approach 2:
Test signal lines act as intermediaries between the pixel array on the first substrate and the failure detection circuits on the third substrate. These intermediary pathways allow detection signals to traverse through the vertical connections (via holes) between substrates, enabling indirect detection of connection failures that would otherwise be inaccessible.
3Volume of moving object
If substrates are stacked closer to reduce size, then miniaturization improves, but signal transmission reliability deteriorates
Solution Approach 1:
Failure detection circuits continuously monitor signal transmission through test signal lines connecting substrates. When transmission failures or anomalies are detected in the vertical signal paths, the system provides feedback to indicate substrate connection issues, enabling real-time reliability assessment despite close substrate spacing for miniaturization.
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 structure allows for accurate failure detection in imaging devices with stacked substrates, ensuring reliable driving support by promptly terminating operations in case of failure, thereby preventing accidents.
Implementation Method 1
connected via through-chip vias
Data Source
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AI summary
The present disclosure relates to an imaging apparatus and an imaging method, a camera module, and an electronic apparatus that are capable of detecting a failure in an imaging device having a structure in which a plurality of substrates are stacked. The timing at which a row drive unit provided in a second substrate outputs a control signal for controlling accumulation and reading of pixel signals in a pixel array provided in a first substrate is compared with the timing at which the control signal output from the row drive unit is detected after passing through the pixel array. Depending on whether or not the timings coincides with each other, a failure is detected. The present disclosure can be applied to an imaging apparatus mounted on a vehicle.