MEMS Scanning Mirror Laser Fringe Pattern Generation
Solution Overview
Problem
Current optical 3D measurement technologies, such as structured light projection, face limitations in resolution and depth of field, particularly with digital light projection systems which have fixed patterns and limited resolution, and physical fringe patterns which are inflexible and restricted by imaging relationships, hindering accurate and flexible three-dimensional measurement.
Innovation Solution
A method using a laser beam reflected by a MEMS scanning mirror, modulated with sinusoidal or cosinusoidal signals to create a programmable analog fringe pattern with extended depth of field, allowing two-dimensional scanning and continuous light intensity modulation for improved resolution and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital light projection technology is used, then programmability and measurement accuracy are improved, but resolution is limited and depth of field is restricted
Solution Approach 1:
The patent replaces digital light projection with a mechanical scanning system using a laser and MEMS mirror. The laser beam is scanned across the object surface by the MEMS mirror to generate fringes, eliminating the fixed resolution limit of digital projectors while maintaining programmability through electronic control of scan parameters.
Solution Approach 2:
The system uses dynamic scanning of a laser beam across the object surface rather than projecting a static pattern. The MEMS mirror enables rapid scanning motion, and the fringe pattern is synthesized dynamically during scanning, allowing extended depth of field and improved adaptability to different measurement scenarios.
2Measurement precision
If physical fringe pattern is used, then resolution is very high, but flexibility and programmability are lost
Solution Approach 1:
The patent replaces physical fringe patterns with a laser scanning system controlled by electronic signals. The laser beam is modulated and scanned to generate fringes on demand, achieving high resolution through precise beam control while maintaining full programmability through software control of scan parameters and fringe characteristics.
Solution Approach 2:
The system generates fringes through periodic modulation of the laser beam intensity and periodic scanning motion of the MEMS mirror. This periodic action creates the interference pattern necessary for measurement while allowing dynamic adjustment of fringe frequency, phase, and other parameters for different measurement requirements.
3Adaptability or versatility
If digital light projection is used, then programmable signals are achieved, but resolution is limited to display pixel level
Solution Approach 1:
The patent replaces the pixel-based digital projection system with a laser scanning system. The laser beam can be positioned with precision far exceeding display pixel resolution, and the effective resolution is determined by the laser spot size and scanning precision rather than by a fixed pixel grid, achieving sub-pixel resolution capability.
4Ease of manufacture
If imaging relationship is used for pattern projection, then pattern formation is achieved, but depth of field limitation occurs
Solution Approach 1:
The system transitions from static imaging projection to dynamic laser scanning. The fringe pattern is generated through the temporal sequence of laser beam positions during scanning rather than through optical imaging, eliminating depth of field constraints while maintaining the ability to form accurate patterns on the object surface.
Solution Approach 2:
The patent extracts the fringe pattern generation from the optical imaging process and implements it through direct laser scanning. By separating pattern formation from imaging requirements, the system eliminates the depth of field limitation inherent in imaging-based projection while maintaining pattern accuracy through direct control of laser beam position and intensity.
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 significantly extends the depth of field by more than 10 times compared to digital light technology, enhancing measurement accuracy and range while reducing discretization errors, enabling high-resolution, programmable, and flexible 3D measurements.
Implementation Method 1
a laser beam emitted by a laser is reflected by a mirror once, passes through a round diaphragm and is incident on an MEMS scanning mirror; the beam is reflected by the MEMS scanning mirror to the surface of a tested object
Implementation Method 2
the MEMS scanning mirror is stimulated by a drive signal generated by a drive board to turn two-dimensionally, so as to drive the laser beam to perform scanning
Implementation Method 3
the laser is controlled by a sinusoidal current signal generated by a drive board so as to sinusoidally modulate the brightness of the laser beam
Data Source
AI summary
Provided is a generation method for a programmable analog fringe pattern with an extended depth of field. A laser emits a laser beam. After focusing and collimation thereof with a collimating lens, a collimated Gaussian laser beam meeting requirements is obtained. The laser beam is reflected by a mirror once, passes through a round diaphragm and is incident on a MEMS scanning mirror. The beam is reflected by the MEMS scanning mirror to the surface of a tested object. The laser is controlled by a sinusoidal current signal generated by a drive board so as to sinusoidally modulate the brightness of the laser beam. The MEMS scanning mirror is stimulated by a drive signal generated by the drive board to turn two-dimensionally, so as to drive the laser beam to perform scanning, thus generating a fringe pattern image.