MEMS Diffractive Gratings for LIDAR Beam Steering
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Solution Overview
Problem
Conventional LIDAR systems are bulky and costly due to numerous components, and existing MEMS-based beam steering technologies face limitations in achieving high speed and efficient beam control, particularly with ribbon-based structures that require compromises between speed, optical throughput, and voltage requirements.
Innovation Solution
The use of microelectromechanical structures with electrostatically deformable diffractive elements, such as L-shaped or T-shaped diffractive elements, that can flex independently to create variable blazed gratings for efficient beam modulation and control, allowing for continuous or stable deflection to manage beam steering effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional LIDAR systems use numerous components including scanning mirrors and rotating dishes, then beam control capability is achieved, but system size becomes bulky and manufacturing cost increases
Solution Approach 1:
The patent combines multiple beam control functions (scanning, focusing, beam shaping) into a single integrated MEMS device with an array of micro-mirors, eliminating the need for separate scanning mirrors, rotating dishes, and other bulky components while maintaining full beam control capability
Solution Approach 2:
The patent replaces mechanical scanning systems (rotating mirrors, moving parts) with electrostatically actuated MEMS micro-mirors that achieve beam steering through electrical fields, eliminating mechanical complexity and reducing system size
2Productivity
If ribbon-based MEMS structures are used for beam steering, then device robustness and scanning speed improve, but optical throughput decreases and voltage requirements increase
Solution Approach 1:
The patent divides the continuous ribbon structure into discrete segmented micro-mirror elements, each independently controllable, which maintains the robustness and speed advantages of ribbon structures while improving optical throughput by allowing precise control of individual segments and reducing unwanted diffraction effects
Solution Approach 2:
The patent applies different properties to different parts of the device - each micro-mirror segment can have independently optimized characteristics for its specific function in the beam pattern, allowing simultaneous optimization of scanning speed, optical throughput, and voltage requirements across different regions
3Quantity of substance
If ribbon length is increased to improve optical throughput, then more light is captured, but oscillation speed decreases and device becomes less robust
Solution Approach 1:
The patent segments the long ribbon into multiple shorter micro-mirror elements, each with optimized length for high oscillation speed, while the collective array of segments maintains overall optical throughput by distributing the light-capturing function across multiple elements
Solution Approach 2:
The patent uses composite structures for the micro-mirror elements combining materials with high mechanical strength-to-weight ratios, enabling faster oscillation speeds while maintaining structural robustness and optical reflectivity properties
4Device complexity
If passive MEMS scanning systems are used, then device simplicity is maintained, but ability to hold beam at specific angles for detailed measurement is lost
Solution Approach 1:
The patent implements dynamic control of the MEMS micro-mirror array, allowing the system to transition between passive scanning mode and active beam holding mode by selectively actuating individual micro-mirors to maintain stable beam positions for detailed measurement while preserving overall system simplicity
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 enables high-speed, robust beam control with improved optical efficiency and reduced voltage requirements, enabling efficient beam steering and phase modulation for LIDAR and structured light applications, while maintaining a large effective reflective area for significant signal strength.
Implementation Method 1
applying a predetermined electrostatic force corresponding to each diffractive element so as to flex each diffractive element independently from other diffractive elements
Implementation Method 2
the diffractive elements act to reflect the light as planar mirrors
Implementation Method 3
electrostatically deformable diffractive elements... to create variable blazed gratings for efficient beam modulation and control
Data Source
AI summary
MEMs-based variable blazed gratings are provided for passive or active phase modulation and beam control in LIDAR among other applications. A system and method for modulating light uses a microelectromechanical structure having deformable diffractive elements. The light is directed to the diffractive elements which act to reflect the light as planar mirrors. Applying a predetermined electrostatic force corresponding to each diffractive element flexes each diffractive element independently from other diffractive elements. Each diffractive element is either flexed continuously through a range of deflected positions or held stably at a single deflected position to interfere with the light through phase changes imparted according to the laws of diffraction.