Reconfigurable TOF Macropixel OR Logic for Lens Misalignment
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Solution Overview
Problem
Conventional time of flight ranging systems face manufacturing defects such as misalignment of lenses over single photon avalanche diodes (SPADs), leading to incomplete light detection and inaccurate distance measurement due to the lack of compensation mechanisms.
Innovation Solution
The implementation of reconfigurable OR logic circuitry within macropixels, allowing for selective signal passing and combination between neighboring photodetection blocks, which compensates for manufacturing irregularities by adjusting the active area of the photodetection array to match the lens misalignment, thereby enhancing light detection and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fixed logic circuitry is used in each macropixel, then the device structure is simple, but manufacturing yield and detection accuracy deteriorate due to lens misalignment
Solution Approach 1:
The logic circuitry transitions from a fixed configuration to a dynamically reconfigurable one. Each macropixel's logic circuitry can be programmed at runtime to route detection signals to different output locations based on the actual lens position, allowing the system to adapt to manufacturing variations without requiring complex physical reconfiguration
Solution Approach 2:
The system changes the operational parameters of the logic circuitry by programming different routing configurations. The logic circuitry can be configured to pass signals to adjacent macropixel outputs or skip certain outputs, effectively changing the detection array's active area parameters to match the lens position
2Measurement precision
If the photodetection array has fixed active area, then the device structure is simple, but detection accuracy deteriorates when lens is misaligned
Solution Approach 1:
The active area of the photodetection array becomes dynamic through software control. By reconfiguring which macropixel outputs are active and how they are combined, the system can shift the effective detection area to match the lens position, improving measurement precision without physical movement
Solution Approach 2:
The logic circuitry performs multiple functions: it combines signals from multiple photodiodes within a macropixel, routes signals to appropriate output locations based on lens position, and can compensate for misalignment by redirecting signals to neighboring macropixel outputs
3Ease of manufacture
If no compensation mechanism is provided, then the device structure is simple, but manufacturing yield suffers due to lens misalignment
Solution Approach 1:
The system performs self-compensation for manufacturing defects. The logic circuitry is programmed to automatically adjust signal routing based on the actual lens position, allowing the device to correct its own manufacturing errors without requiring external calibration or complex manufacturing processes
Solution Approach 2:
The logic circuitry is pre-programmed with the capability to compensate for lens misalignment. During operation, the system can be configured to match the specific lens position, effectively preparing the detection array in advance to work optimally with the manufactured lens position
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 improves the manufacturing yield and accuracy of time of flight ranging systems by effectively compensating for lens misalignment, ensuring comprehensive light detection and precise distance measurement.
Implementation Method 1
an array of single photon avalanche diodes (SPADs)... reflected light detector... detecting the reflected light
Data Source
AI summary
An electronic device includes at least one photodetection block, where the at least one photodetection block includes a plurality of macropixels arranged into an array. Each macropixel includes an array of photodiodes, with logic circuitry coupled to outputs of the array of photodiodes and configured to generate a detection signal as a function of logically combining the outputs of the array of photodiodes. Each macropixel has associated therewith selection circuitry configured to selectively pass the detection signal to output combining logic or to output combining logic of at least one neighboring macropixel of the plurality thereof. The output combining logic has inputs coupled to the selection circuitry and to the selection circuitry of the at least one neighboring macropixel, and is configured to generate an output detection signal as a function of logically combining outputs of the selection circuitry and the selection circuitry of the at least one neighboring macropixel.