Laser Distance Measurement Using Optical Mixing and Frequency Division
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Solution Overview
Problem
Laser distance measurement devices face challenges in accurately measuring distance due to interference from high-frequency electrical signals and increased complexity from additional optical paths required for reference signal generation, which complicates the measurement process.
Innovation Solution
A method involving a control circuit to generate synchronization signals, signal generators to produce synchronous periodic signals, and an optical detector to determine distance based on the measurement signal and a reference signal, reducing the need for additional optical paths and minimizing circuit interference by using frequency division to generate low-frequency measurement signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical mixing process is used to generate reference signal, then reference signal can be obtained, but circuit complexity increases and signal interference occurs
Solution Approach 1:
The patent extracts the reference signal generation from the electrical mixing process and implements it through optical mixing using a beam splitter and two laser transmitters. This separates the reference signal path from the measurement signal path, eliminating the need for electrical mixers and reducing circuit complexity while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces an optical intermediary (beam splitter and optical path) to generate the reference signal instead of using electrical mixing. The beam splitter divides the laser beam into measurement and reference paths, allowing reference signal generation without electrical interference and simplifying the overall circuit design.
2Measurement precision
If optical mixing process is used to generate reference signal, then reference signal can be obtained, but additional optical path increases device complexity
Solution Approach 1:
The patent merges the reference optical path with the measurement optical path by using a beam splitter to divide a single laser beam into two paths. This eliminates the need for separate laser transmitters and optical paths for reference signal generation, reducing device complexity while maintaining optical mixing functionality.
Solution Approach 2:
The single laser transmitter serves dual purposes: generating both the measurement signal (through the measurement optical path) and the reference signal (through the reference optical path). This multi-functionality reduces the number of components needed and simplifies the overall device structure.
3Length of stationary object
If high-frequency laser signal is used for measurement, then measurement range is improved, but phase difference measurement becomes difficult
Solution Approach 1:
The patent introduces an intermediary frequency conversion process where the high-frequency laser signal is mixed with a local oscillator signal to produce a low-frequency intermediate signal. This intermediate signal retains the phase difference information while being easier to measure, thus resolving the measurement difficulty without sacrificing the extended measurement range provided by the high-frequency laser.
Solution Approach 2:
The patent changes the frequency parameter of the measurement signal from high-frequency (laser frequency) to low-frequency (intermediate frequency) through mixing with a local oscillator. This parameter transformation makes phase difference measurement feasible while preserving the distance measurement capability through the frequency relationship between the signals.
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 simplifies the measurement device structure, reduces signal processing complexity, and improves measurement accuracy by directly utilizing a synchronized reference signal, enhancing the efficiency and reliability of laser distance measurement.
Implementation Method 1
generating, by an optical detector, a measurement signal in response to a mixing of the second periodic signal and a laser beam reflected from the target
Data Source
AI summary
The present disclosure relates to a method and a system for laser distance measurement. The method includes: obtaining, from a control circuit, a synchronization signal; generating, by at least one signal generator, a first periodic signal, a second periodic signal, and a third periodic signal based on the synchronization signal; emitting, by a laser emitting device, a laser beam toward a target, the laser beam being generated under a modulation of the first periodic signal; generating, by an optical detector, a measurement signal in response to a signal mixing of the second periodic signal and a reflected laser beam from the target; and determining a distance to the target based on the measurement signal and the third periodic signal.