Vibrating Beam Accelerometer Electrode Patterning
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Solution Overview
Problem
Existing methods for patterning electrodes on vibrating beam accelerometers, such as aperture or shadow masks and laser ablation, face limitations in feature size, cost, and line of sight constraints, particularly for double-ended tuning fork resonators, which affect the accuracy and efficiency of the accelerometers.
Innovation Solution
The use of selective laser etching (SLE) to form electrodes on resonator beams with a reduced gap of less than or equal to 250 micrometers, allowing for precise patterning and improved electrical isolation between electrodes, enabling better performance and efficiency in vibrating beam accelerometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional aperture or shadow masks are used for patterning electrodes, then manufacturing is simpler, but electrode gap size cannot be reduced below certain limits and line of sight constraints apply
Solution Approach 1:
The patent replaces traditional mechanical aperture or shadow mask systems with a laser-based patterning system. The laser beam can be precisely controlled to etch electrodes with gaps of 250 micrometers or less without requiring physical masks, eliminating line of sight constraints and enabling smaller feature sizes while maintaining manufacturing feasibility.
2Manufacturing precision
If laser ablation is used for electrode patterning, then electrode gap can be reduced, but cost increases and line of sight constraints remain
Solution Approach 1:
The patent modifies the laser processing parameters, specifically using a laser wavelength that is highly absorbed by aluminum (such as UV or blue laser). This parameter change enables efficient electrode patterning with reduced gaps while controlling manufacturing cost through optimized laser absorption and reduced processing time.
3Measurement precision
If electrode gap is reduced to improve Q factor and resonance driving efficiency, then accelerometer accuracy and power efficiency improve, but electrical isolation between electrodes becomes more difficult to maintain
Solution Approach 1:
The patent uses laser etching to create precise electrode patterns with controlled gaps of 250 micrometers or less. The laser process provides superior edge definition and gap uniformity compared to mask-based methods, ensuring reliable electrical isolation while achieving the small gap sizes needed for high Q factor and accurate acceleration measurement.
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
SLE enhances the accuracy and power efficiency of vibrating beam accelerometers by allowing for smaller electrode gaps, improving the Q factor and resonance driving efficiency, while being cost-effective and overcoming the constraints of traditional methods.
Implementation Method 1
selective laser etching may be used to form or shape the electrodes, e.g., via removing a portion of resonator beam material
Implementation Method 2
the resonator beam comprises a piezoelectric material
Data Source
AI summary
An example proof mass assembly includes a proof mass, a proof mass support, and a flexure connecting the proof mass to the proof mass support. The proof mass is configured to rotate relative to the proof mass support via the flexure. The proof mass assembly includes a resonator beam connected to a first major surface of the proof mass and a first major surface of the proof mass support. The resonator beam includes a first electrode disposed on a surface of the resonator beam and a second electrode disposed on the surface of the resonator beam that is configured to have an opposite charge than that of the first electrode. The resonator beam comprises a gap between the first electrode and the second electrode on the surface of the resonator beam that is less than or equal to 250 micrometers.