Integrated Magnet Actuator for MEMS Mirrors
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Solution Overview
Problem
Existing magnetically actuated reflector devices for MEMS micromirrors in LIDAR and projection applications have complex and expensive manufacturing processes due to the heterogeneous assembly of permanent magnets, leading to increased energy consumption and device bulk.
Innovation Solution
A magnetically actuated reflector device with a substrate having a movable part with a mirror integrally attached, an actuator module comprising a magnet and electrical line, and a stack of bilayers based on antiferromagnetic and ferromagnetic materials, deposited using microelectronic techniques to simplify manufacturing and improve compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanent solid magnet is assembled heterogeneously with a micromirror and coil, then the micromirror can be actuated magnetically, but the manufacturing process becomes complex and expensive
Solution Approach 1:
The patent merges the magnet and coil into a single integrated actuator module that is deposited as one homogeneous structure using microelectronic techniques. This eliminates the need for separate assembly steps of heterogeneous components (permanent magnet, coil, micromirror), thereby simplifying manufacturing while maintaining magnetic actuation functionality.
Solution Approach 2:
The patent replaces the mechanical assembly process (gluing, attaching separate magnet and coil components) with a microelectronic deposition process. The actuator module is formed by depositing layers of magnetic material and conductive material in a integrated fabrication sequence, substituting mechanical joining with a unified deposition-based manufacturing approach.
2Ease of operation
If a permanent solid magnet is used for magnetic actuation, then the micromirror can be rotated, but the device volume increases
Solution Approach 1:
The patent uses thin film structures for both the magnet and coil within the integrated actuator module. The magnetic material is deposited as a thin layer (micronic thickness) rather than using a bulky permanent magnet, enabling micromirror rotation while minimizing the volume occupied by the actuation components.
3Reliability
If a permanent solid magnet is used for magnetic actuation, then the micromirror can be actuated, but energy consumption increases
Solution Approach 1:
The patent employs composite material structures where a thin magnetic layer is combined with a conductive coil layer in close proximity. This composite configuration creates a highly efficient magnetic actuator that generates sufficient magnetic field strength with lower current, thereby reducing energy consumption compared to conventional permanent magnet assemblies.
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 simplifies manufacturing, reduces costs, and improves the compactness and reliability of the reflector device by eliminating complex assembly steps and minimizing the size of the magnet, thereby reducing energy consumption.
Implementation Method 1
an actuator module comprising at least one magnet and at least one electrical line configured to be crossed by an electric current (i)... configured to rotate the second part of the substrate and the mirror by a driving force generated by an interaction between the at least one magnet and the electric current passing through the at least one electrical line
Implementation Method 2
a heat treatment of the deposited stack under application of a magnetic field so as to magnetize the stack in at least one magnetization direction
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Magnetically actuated reflective device and associated method The invention relates to a reflective device (1) comprising: • a substrate (S), • a mirror (10) configured to be pivoted about at least one axis of rotation (A1), • an actuator module (6) comprising at least one magnet (20) and at least one electrical line (30) configured to be traversed by an electric current (i), the actuator module (6) being configured to drive the mirror (10) in rotation by a driving force (FL), in which the at least one magnet (20) comprises a stack (2) of at least one bilayer comprising a first sub-layer (3) based on an antiferromagnetic material and a second sub-layer (4) based on a ferromagnetic material. The invention also relates to the method of manufacturing the reflective device (1) in which the at least one magnet (20) is formed by depositing the stack (2) on the substrate (S).