Time of Flight Sensor Segmentation for Pulse Precision
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Solution Overview
Problem
Time-of-flight (TOF) optical sensors face challenges in accurately measuring the propagation time of light pulses and calculating distance with minimal data captures, especially when dealing with irregularly shaped pulses and ambient light interference, which affects measurement precision and response times.
Innovation Solution
The TOF sensor device employs a photo-sensor component with multiple capacitors to capture leading and trailing portions of reflected light pulses, using advanced timing control signals to isolate pulse information from ambient light, and employs methods like the ratio and center of mass techniques to calculate propagation time and distance with high precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor captures the entire reflected light pulse, then the measurement precision is improved, but the response time increases due to longer acquisition time required to capture the full pulse duration
Solution Approach 1:
The patent divides the reflected light pulse into multiple segments (first portion, second portion, third portion, fourth portion) corresponding to different time intervals. The photo-detector captures these segmented portions separately, allowing the system to process partial pulse information quickly rather than waiting for the entire pulse duration. This segmentation enables faster response times while maintaining measurement precision through selective combination of captured portions.
2Measurement precision
If the sensor uses multiple data captures to improve measurement accuracy, then the measurement precision is improved, but the complexity of the measuring system increases
Solution Approach 1:
The measuring circuit is segmented into multiple independent capture channels, each dedicated to capturing a specific portion of the reflected pulse. This modular segmentation allows each channel to operate independently with simplified circuitry, avoiding the need for a single complex circuit that would handle all captures simultaneously. The segmented approach reduces overall system complexity while enabling multiple data captures for improved precision.
Solution Approach 2:
The patent employs periodic capturing of light pulse portions at different time intervals within the pulse duration. By systematically capturing portions at regular time intervals rather than attempting to capture the entire pulse continuously, the measuring circuit achieves high measurement accuracy through multiple discrete measurements while maintaining relatively simple circuit architecture.
3Measurement precision
If the sensor captures the full duration of irregularly shaped pulses, then the measurement precision is improved, but the response time increases and ambient light interference worsens
Solution Approach 1:
The patent segments the capture window into specific time portions that correspond to the expected arrival time of the reflected light pulse. By capturing only these relevant time portions rather than the entire pulse duration or continuous ambient light periods, the system minimizes the integration of ambient light interference while maintaining precision measurements of the actual reflected pulse signal.
Solution Approach 2:
The system uses preliminary timing information about when the reflected pulse is expected to arrive to pre-configure the capture windows. By anticipating the pulse arrival time and setting up capture portions accordingly before the actual measurement, the system can focus detection resources on the relevant time intervals, reducing sensitivity to ambient light that occurs outside these predetermined windows.
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 approach enables accurate distance measurement with short acquisition and response times, maintaining high precision even with irregular pulses and minimizing ambient light effects, thus enhancing the performance of TOF sensors in industrial and safety applications.
Implementation Method 1
a photo device configured to generate electrical energy in proportion to a quantity of received light
Data Source
AI summary
A time of flight sensor device is provided that is capable of generating accurate information relating to propagation time of emitted light pulses using a small number of measurements or data captures. By generating pulse time of flight information using a relatively small number of measurement cycles, object distance information can be generated more quickly, resulting in faster sensor response times. Embodiments of the time of flight sensor can also minimize or eliminate the adverse effects of ambient light on time of flight measurement. Moreover, some embodiments execute time of flight measurement techniques that can achieve high measurement precision even when using relatively long light pulses having irregular, non-rectangular shapes.