Optoelectronic Sensor Sub-picosecond Time Resolution via Optical Comb Filtering
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Solution Overview
Problem
Conventional optoelectronic sensors using the light transit time principle face limitations in achieving high time precision for distance measurement, particularly due to the restricted time resolution of digital components and the need for cost-intensive electronics to achieve sub-picosecond precision.
Innovation Solution
The solution involves increasing time resolution beyond the discrete time pattern by using a statistical approach with bin counts and center of mass calculations, allowing for precise selection of transmission times with sub-picosecond precision, and employing a digital component to refine the time base unit with frequencies derived from a master clock, enabling high-resolution time increments without requiring complex hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional digital components (FPGAs, programmable logic) are used for time measurement, then device complexity and cost are reduced, but time resolution is limited to nanoseconds rather than picoseconds
Solution Approach 1:
The patent replaces conventional electronic time measurement systems (FPGAs, programmable logic) with an optical comb filter system. The comb filter uses optical interference patterns to achieve picosecond time resolution, substituting electronic processing with optical processing. This allows high-precision time measurement without requiring complex high-speed electronics.
Solution Approach 2:
The patent changes the measurement parameter from electronic clock cycles (nanosecond resolution) to optical interference fringe patterns (picosecond resolution). By using the wavelength of light and interference patterns instead of electronic timing signals, the system achieves higher time resolution through a different physical domain.
2Measurement precision
If interpolation methods are used to improve time resolution, then measurement precision is improved, but device complexity and computational effort increase
Solution Approach 1:
The patent replaces computational interpolation methods with an optical interference-based measurement system. Instead of using digital signal processing and function fitting algorithms to estimate time of flight, the system uses optical comb filtering where the interference pattern directly encodes the time information, eliminating the need for complex post-processing calculations.
3Measurement precision
If the discrete time pattern resolution is refined, then time precision is improved, but the inherent limitations of the time pattern resolution remain
Solution Approach 1:
The patent transitions from discrete time sampling to continuous optical phase measurement. The comb filter generates a spectrum of frequency components that create interference patterns, allowing time measurement through phase detection rather than discrete time binning. This continuous measurement approach overcomes the fundamental resolution limits of discrete sampling.
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 method allows for cost-effective, high-precision distance measurement with sub-picosecond resolution, overcoming the limitations of conventional systems by using statistical amplitude information and advanced digital signal processing techniques.
Implementation Method 1
a light transmitter 12 transmits light signals and a light receiver 16 surrounding the light transmitter 12 detects reflected light signals
Data Source
AI summary
An optoelectronic sensor (10) for the measurement of distances or distance changes in accordance with the light transit time principle is provided having a light transmitter (12) for the transmission of a light signal and having a light receiver (16) for the reception of the remitted or reflected light signal, wherein an evaluation unit (18) is provided which is made to trigger the transmission of a light signal at a transmission time in a respective measurement period (100) and to sample the received light signal as well as to accumulate a histogram (110) of such received light signals over a plurality of measurement periods (100) and to determine the reception time from the histogram (110) and the light transient time from this. In this respect, a unit (40) for the fine setting of a transmission time is provided which is made to shift the respective transmission time within the measurement periods (100) by an offset, with the offsets forming a distribution (56, 60) whose center of mass forms a desired transmission time.