Optical Interference Ranging Sensor Disturbance Rejection
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Solution Overview
Problem
Mach-Zehnder type optical interference ranging sensors are prone to measurement errors due to disturbances such as vibration and temperature changes, which affect the polarizations of the reference and measurement light.
Innovation Solution
The optical interference ranging sensor is designed with a plurality of light receiving channels corresponding to one light projecting channel, where the reference light also propagates through at least one of the light projecting or receiving channels, thereby making the effects of disturbances comparable and reducing their impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Mach-Zehnder type optical interference ranging sensor is used, then distance measurement capability is achieved, but measurement errors occur due to disturbances such as vibration and temperature changes affecting polarization
Solution Approach 1:
The patent combines the reference light path with the measurement light path by having the reference light propagate through the same optical fiber as the measurement light. This merging of paths ensures that both lights experience identical disturbances, allowing the interference signal to cancel out disturbance effects and improve measurement accuracy.
Solution Approach 2:
The patent uses an optical coupler as an intermediary component to combine the reference light and measurement light into a single optical fiber. This intermediary mechanism enables the reference light to be introduced into the measurement light path without requiring separate dedicated paths, thereby reducing the impact of external disturbances.
2Reliability
If multiple light receiving channels are provided for one light projecting channel, then speckle reduction is achieved, but device complexity increases
Solution Approach 1:
The patent segments the light receiving function into multiple independent channels that can receive light from a single projecting channel. This segmentation allows the system to process multiple signal paths simultaneously, enabling speckle reduction through differential measurement while maintaining a manageable structural complexity.
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 configuration enhances the sensor's resistance to disturbances, improving the accuracy of distance measurements by making the effects of vibrations and temperature changes comparable for both measurement and reference light.
Implementation Method 1
a light source that projects light while changing a wavelength
Implementation Method 2
an interferometer that is supplied with light projected from the light source, and generates interference light based on measurement light that is illuminated onto a measurement target by a sensor head and reflected, and reference light that follows an optical path at least partially different from an optical path of the measurement light
Implementation Method 3
a light receiver that receives the interference light from the interferometer and converts the interference light into an electric signal
Implementation Method 4
a reference light generator that generates the reference light by reflecting a part of the light propagating in the light projecting channel
Data Source
AI summary
An optical interference ranging sensor is equipped with a plurality of light receiving channels corresponding to one light projecting channel. The optical interference ranging sensor includes a light source that projects light while changing a wavelength; an interferometer that generates interference light based on measurement light and reference light; a light receiver that receives the interference light from the interferometer; and a processing unit that calculates a distance from the sensor head to the measurement target. The interferometer includes a light projecting channel configured to propagate light supplied from the light source toward the sensor head and irradiate the measurement target with the light from the sensor head. A plurality of light receiving channels are configured to receive the measurement light and propagate the measurement light toward the light receiver. At least one of the light projecting channel and the plurality of light receiving channels further propagates the reference light.