Imaging Pixel Pulse Trigger Assembly for Time-of-Flight
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Solution Overview
Problem
Traditional pixel designs can only detect active illumination pulses and fail to accurately measure time of flight and distance due to their inability to properly detect time of flight.
Innovation Solution
A pixel system with a pulse trigger assembly and a timer system that includes trigger switches and a time-of-flight module, allowing for accurate detection of pulses at multiple threshold voltages and determination of time of flight based on voltage ramp analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional pixel designs are used to detect active illumination pulses, then the detection function is provided, but the time of flight measurement accuracy deteriorates due to inability to properly detect time of flight
Solution Approach 1:
The pixel is divided into distinct functional regions: a photodetector region for detecting incident light pulses and a separate timing region containing the ramp generator and trigger circuitry. This segmentation allows independent optimization of detection and timing functions, enabling accurate time-of-flight measurement without requiring complete redesign of the entire pixel structure.
Solution Approach 2:
The pixel design integrates multiple functions into a single pixel structure: it can detect both passive illumination and active laser pulses, perform time-of-flight measurements, and generate timing signals. The ramp generator and trigger circuitry are designed to work with both passive and active imaging modes, making the pixel multi-functional without requiring separate dedicated pixels for each function.
2Measurement precision
If conventional detection methods are used, then the detection function is satisfied, but the ability to measure distance accurately deteriorates
Solution Approach 1:
The ramp voltage is generated and prepared in advance before the light pulse arrives at the pixel. The ramp generator continuously produces a linearly increasing voltage signal that serves as a time reference. When the pulse is detected, the timing circuit captures the instantaneous ramp voltage value, which directly corresponds to the time of flight. This preliminary preparation of the ramp signal enables accurate time measurement without requiring complex real-time calculations.
3Measurement precision
If single threshold detection is used, then the detection process is simple, but the measurement accuracy deteriorates due to errors in time of flight determination
Solution Approach 1:
Different threshold levels are implemented at different voltage levels within the timing circuit. Instead of using a single uniform threshold, the system employs multiple comparators with distinct threshold voltages (e.g., 20%, 40%, 60%, 80% of full scale). Each threshold provides localized detection points that, when combined, give a more accurate determination of the pulse arrival time and reduce the impact of noise or signal variability at any single threshold level.
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
The system enables accurate time-of-flight measurements by activating trigger switches at specific threshold voltages, reducing errors through multi-threshold readings, and allowing for simultaneous passive imaging and active pulse detection.
Implementation Method 1
A pixel can include a pulse trigger assembly configured to detect a pulse at one or more threshold voltages
Data Source
AI summary
A pixel system for an imaging device can include one or more pixels comprising a pulse trigger assembly configured to detect a pulse at one or more threshold voltages, a timer system forming part of and/or connected to the one or more pixels, the timer system comprising one or more trigger switches. The pulse trigger assembly can be configured to activate the one or more trigger switches in response to detecting the pulse at the one or more threshold values. The pixel system can include a time-of-flight (TOF) module operatively connected to the one or more pixels and/or the timer system to determine a TOF based on an output from the timer system while simultaneously performing either or both passive imaging and asynchronous laser pulse detection.