Optoelectronic Sensor Distance Measurement Parallel Sampling
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Solution Overview
Problem
Conventional methods for determining the time of flight of light with high precision are costly and unable to achieve the required accuracy without expensive electronics.
Innovation Solution
A sensor that samples the received light pulse in parallel and statistically evaluates a large number of individual pulses, using delay paths that introduce minimal jitter, and employs recoding techniques to compensate for signal delay fluctuations, allowing for high-precision distance measurement with inexpensive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pulse transit time systems use expensive electronics to achieve picosecond measurement accuracy, then measurement precision is improved, but device cost and complexity increase
Solution Approach 1:
The patent divides the time measurement task into multiple coarse time bins (e.g., 10 ns intervals) and uses parallel sampling channels to measure signal characteristics in each bin. This segmentation allows achieving picosecond precision through statistical evaluation of many pulses distributed across bins, rather than requiring expensive picosecond-resolution electronics for each individual measurement.
Solution Approach 2:
The system uses periodic modulation of the light source (e.g., sinusoidal modulation at frequencies like 100 MHz) and samples the reflected signal at multiple phase positions within each modulation period. By repeating this periodic measurement process many times and statistically evaluating the results, the system achieves high precision without requiring expensive high-speed electronics.
2Measurement precision
If parallel sampling with multiple delay paths is used to increase sampling frequency, then measurement precision is improved, but signal delay fluctuations (jitter) increase
Solution Approach 1:
The patent pre-calibrates the delay paths to introduce specific, known time offsets (e.g., 0 ns, 5 ns, 10 ns) between parallel sampling channels. This preliminary setup allows the system to compensate for delay path variations during evaluation, as the relative timing relationships are established in advance and can be accounted for in the statistical analysis.
Solution Approach 2:
The system measures signal characteristics (e.g., zero-crossing times, peak positions) in each delay path and uses this feedback information to adjust and synchronize the timing references. By continuously monitoring and correcting for delay path variations, the system maintains reliable timing despite the presence of multiple parallel paths with different delays.
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 solution enables an inexpensive, miniaturizable, and robust sensor capable of precise distance determination in the millimeter range, resistant to external interference, with improved signal-to-noise ratio and inherent error correction.
Implementation Method 1
a light transmitter (12) which transmits individual light pulses towards a target object (14)
Implementation Method 2
the distance reflected by the object is received
Implementation Method 3
a photodetector (16) which converts the received light pulses into electrical signals
Data Source
Figure 1~2
Figure 3~5
Figure 6a~6b
AI summary
The optoelectronic sensor (10) has a light emitter (12) formed to send single light pulses in such a manner that the light received signals are supplied to the delay paths (36), with a varying temporal misalignment. An analysis unit is provided, which is formed to average compensation of the temporal misalignment over the single light pulses to adjust fluctuations in the delay paths. An independent claim is included for a method for measuring distance after light retention method.