Coupled Micromechanical Resonator Wafer Assembly for Large Scan Angles
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Solution Overview
Problem
Conventional micromechanical resonators suffer from limited actuation energy, resulting in short scan angles, high power consumption, slow start-up times, and high manufacturing costs due to inefficient energy transfer and complex fabrication processes.
Innovation Solution
A micromechanical resonator wafer assembly with a coupled oscillation system, comprising an actuator wafer and a device wafer, where the outer actuator layer drives the inner actuators to achieve resonant or near-resonant oscillations, enabling large scan angles at low power consumption and simplifying the fabrication process through reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional internal actuation structures (piezo-electric thin film layers, electrostatic comb drives, or magnetic force stimulation) are used to actuate MEMS mirrors, then the micromechanical resonator can be fabricated, but the actuation energy is limited resulting in short scan angles
Solution Approach 1:
The system is divided into two separate wafer assemblies: an actuator wafer assembly containing the outer actuator layer, and a device wafer assembly containing the inner actuators and oscillation bodies. This segmentation allows each component to be optimized independently and facilitates efficient coupling between them through magnetic interaction, resolving the limitation of conventional integrated structures that constrain actuation energy and scan angle.
Solution Approach 2:
A magnetic coupling mechanism acts as an intermediary between the outer actuator layer and the inner actuators. The outer actuator layer generates a magnetic field that couples with the inner actuators, enabling efficient energy transfer without direct mechanical contact. This intermediary mechanism overcomes the energy transfer limitations of conventional direct actuation structures.
2Power
If conventional actuation structures are used, then the micromechanical resonator can operate, but power consumption is high and start-up time is slow
Solution Approach 1:
The system utilizes resonant oscillation of the oscillation bodies at their eigenfrequencies to achieve efficient actuation. By exciting the oscillation bodies at their natural resonant frequencies through the coupled magnetic field, the system achieves large scan angles with minimal power input and rapid start-up, overcoming the high power consumption and slow response of conventional non-resonant actuation methods.
Solution Approach 2:
The system changes the operational parameters by operating at resonant frequencies rather than non-resonant frequencies. This parameter change enables the oscillation bodies to respond rapidly with large amplitudes using minimal input energy, directly addressing the high power consumption and slow start-up time issues of conventional actuators.
3Ease of manufacture
If conventional micromechanical resonators are fabricated, then devices can be produced, but manufacturing cost is high due to complex fabrication processes
Solution Approach 1:
The fabrication process is segmented into two independent wafer-level manufacturing streams that can be performed separately and then coupled. This segmentation simplifies each individual fabrication process, enables parallel production, and reduces overall manufacturing complexity and cost compared to conventional single-wafer complex integration processes.
Solution Approach 2:
The outer actuator layer wafer assembly can be used with multiple different device wafer assemblies, and vice versa. This universality allows for modular manufacturing where components can be produced in high volumes independently and then combined, reducing per-unit manufacturing cost and simplifying the fabrication process.
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 large scan angles up to 180° and fast start-up times (<1 second) with low power consumption in the milliwatt range, while reducing manufacturing costs and improving product quality through simplified high-volume fabrication.
Implementation Method 1
conventional micromechanical resonator based on aforesaid internal actuation solutions has limited actuation energy
Implementation Method 2
excitation of the oscillation body of the respective inner actuator by transfer of energy from the oscillating part to the oscillating body when the oscillating part of the outer actuator layer is activated with a frequency selected to excite resonant or near-resonant oscillation of the oscillation body
Implementation Method 3
each of the inner actuators including an oscillation body configured to oscillate about one or more axes, the oscillation of the oscillation body having one or more eigenfrequencies
Data Source
AI summary
A micromechanical resonator wafer assembly includes an actuator wafer supporting an outer actuator layer. The outer actuator layer includes an oscillating part configured to be driven by an electrical drive signal. The micromechanical resonator wafer assembly further includes a device wafer mounted on top of the actuator wafer. The device wafer includes a plurality of inner actuators. Each of the inner actuators include an oscillation body configured to oscillate about one or more axes. The device wafer is physically connected to the actuator wafer such that each of the inner actuators forms with the outer actuator layer a coupled oscillation system for excitation of the oscillation body of the respective inner actuator. The micromechanical resonator wafer assembly provides external actuation of the oscillation body of each of the inner actuators by use of the outer actuator layer and hence, provides improved scan angles with fast start-up time.