Time Grating Linear Displacement Sensor Using Alternating Light Field
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Solution Overview
Problem
Current sensors for precision linear displacement measurements in the optical field, such as gratings and laser interferometers, face challenges in achieving high precision, low cost, and ease of production and installation, with grating sensors being difficult to manufacture and costly, and laser interferometers being expensive and susceptible to environmental interference.
Innovation Solution
A time grating linear displacement sensor based on an alternating light field, comprising a fixed and movable pole plate with specific light transmitting surfaces and light sensitive receiving units, utilizing alternating light sources and photoelectric effects to generate electrical signals that reflect differential changes, which are then processed to calculate linear displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If grating sensors are used for precision linear displacement measurements, then measurement precision can be achieved, but manufacturing difficulty increases and cost increases
Solution Approach 1:
The patent replaces the traditional mechanical grating system with a magnetic field-based time grating system. Instead of using physical gratings with finely spaced lines that require precision machining, the invention uses magnetic poles arranged in a time grating pattern that generates a magnetic field distribution equivalent to optical grating effects. This substitution eliminates the manufacturing difficulties associated with creating fine mechanical gratings while maintaining measurement precision through magnetic field sensing.
Solution Approach 2:
The patent changes the fundamental measurement parameter from optical path difference in spatial gratings to time-based magnetic field phase difference. By using alternating magnetic fields that vary with time and position, the system transforms the measurement approach from spatial subdivision to temporal phase measurement, thereby avoiding the need for mechanically precise grating fabrication while achieving equivalent or superior measurement resolution.
2Measurement precision
If laser interferometers are used for highly precise displacement measurements, then measurement precision is improved, but cost increases and reliability decreases due to environmental sensitivity
Solution Approach 1:
The patent substitutes the optical laser interferometer system with a magnetic field-based time grating sensor. Instead of relying on laser beams that are sensitive to environmental factors such as dust, humidity, and temperature variations, the invention uses magnetic fields that penetrate these environmental barriers without significant interference. The magnetic field sensing approach maintains high measurement precision while significantly improving reliability in practical industrial environments.
3Measurement precision
If magnetic field type time grating sensors are used, then measurement precision is achieved, but power consumption increases due to high driving power for stator coils
Solution Approach 1:
The patent employs periodic alternating magnetic fields generated by time-grating magnetic poles that are sequentially energized. Instead of requiring continuous high power to maintain static magnetic fields in traditional magnetic sensors, the system uses time-varying magnetic fields that are generated in periodic sequences. This periodic activation of magnetic poles reduces the average power consumption while maintaining the measurement precision through phase detection of the alternating magnetic field signals.
4Manufacturing precision
If electric field type time grating sensors are used, then production accuracy is improved, but installation difficulty increases due to requirements for short parallel mounting distance
Solution Approach 1:
The patent transitions from the electric field domain to the magnetic field domain, fundamentally changing the physical principle underlying the sensor operation. This dimensional shift from electric to magnetic field-based time grating allows for more flexible installation configurations. Magnetic field sensors can operate effectively over larger air gaps and do not require the stringent parallel mounting conditions needed for electric field sensors, thereby maintaining high production accuracy while significantly easing installation requirements.
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 achieves high precision, low energy consumption, and low cost with ease of production and installation, overcoming the limitations of existing sensors by using alternating light fields to generate accurate linear displacement measurements.
Implementation Method 1
utilizing alternating light sources and photoelectric effects to generate electrical signals
Data Source
AI summary
A time grating linear displacement sensor based on an alternating light field, comprising a fixed pole plate and a movable pole plate, wherein the upper part and the lower part of the fixed pole plate are respectively provided with a row of square fixed pole plate light-transmitting surfaces which are uniformly distributed; the upper part and the lower part at the rear of the fixed pole plate are respectively provided with one group of light-emitting devices; the upper part and the lower part of the movable pole plate are respectively provided with two semi-sinusoidal movable pole plate light-transmitting surfaces; and four light-sensitive receiving units are fixed on the movable pole plate, the photoelectric receiving surfaces of the light-sensitive receiving units covering the movable pole plate light-transmitting surfaces. The two groups of light-emitting devices respectively provide an alternating light field. The movable pole plate moves relative to the fixed pole plate.