Sensor Readout Circuit Digital Remapping for Optical Misalignment
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Solution Overview
Problem
Existing sensor devices face challenges in compensating for optical misalignment between the sensor array and the optics in sensor modules, leading to offsets in the mapping of illuminated zones and field of view.
Innovation Solution
A sensor device with a readout circuit that provides dedicated readout paths for each photodetector, allowing for the shifting of the first subarray to compensate for optical misalignment by re-centering sensor signals, thereby eliminating the need for complex multiplexing or active lens alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If complex multiplexing or active lens alignment is used to compensate for optical misalignment, then alignment precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical alignment systems (active lens alignment) and complex electrical multiplexing with a simplified digital remapping approach implemented in the readout circuit. The readout circuit directly remaps sensor signals to compensate for misalignment offsets, eliminating the need for mechanical adjustment mechanisms and complex multiplexing networks, thereby reducing device complexity while maintaining alignment precision.
2Reliability
If redundant SPAD zones are added to account for misalignment, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent changes the operational parameters of existing SPAD zones through digital remapping in the readout circuit rather than adding physical redundant zones. By dynamically adjusting the mapping between illuminated zones and SPAD readout paths, the system achieves reliability against misalignment without increasing the physical device complexity or adding redundant hardware components.
3Measurement precision
If dedicated TDCs are added for each zone with redundancy, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes the readout circuit universal by implementing a single readout path that can serve multiple SPAD zones through dynamic remapping. Instead of dedicating separate TDCs to each zone, the universal readout circuit compensates for misalignment by remapping signals from any illuminated zone to the appropriate SPAD readout path, thereby maintaining measurement precision while reducing device complexity and cost.
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 solution effectively reduces the impact of optical misalignment, allows for lower production costs, and maintains high accuracy in time-of-flight and 3D imaging applications.
Implementation Method 1
alignment of optics with respect to the sensor array may vary which leads to the problem of an offset in the mapping of illuminated zone on the SPAD array and a field of view of the optics
Data Source
AI summary
A sensor device is provided and includes an array of photodetectors. A readout circuit is connected to the array of photodetectors and provides dedicated readout paths for each photodetector in the array, respectively. Further, the readout circuit includes at least one control terminal. An array of time-to-digital converters is electrically connected to converter output terminals of the readout circuit. Depending on a control signal to be applied at the at least one control terminal, the readout circuit is arranged to electrically connect through the readout paths of photodetectors of a first subarray (11) to the converter output terminals of the readout circuit, respectively, thereby rendering the photodetectors of the first subarray active and photodetectors of a second subarray inactive.