MEMS Resonator Gap Layout for Faster Frequency Adjustment
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Solution Overview
Problem
Existing resonance devices face inefficiencies in frequency adjustment due to ductile deformation of metal films on vibration arms, limiting the change in weights and amplitude, which restricts effective frequency adjustment in micro electro mechanical systems (MEMS).
Innovation Solution
A resonance device design with a larger gap between the distal end of the vibration arm and the upper cover compared to the lower cover, allowing the vibration arm's distal end to collide with the lower cover for efficient weight adjustment, and a method for manufacturing this device that includes exciting the resonator to bring the distal end into contact with the lower cover to adjust the frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distal end portions of vibration arms are caused to collide with the upper cover for frequency adjustment, then the frequency can be adjusted, but the metal film causes ductile deformation without being shaved, resulting in minimal weight change and restricted amplitude
Solution Approach 1:
Instead of colliding the distal end portions with the upper cover as in conventional methods, this invention inverts the approach by causing collision with the lower cover. The resonator structure is designed with the lower cover positioned to receive the distal end portions during vibration, enabling effective material removal and weight adjustment while preventing ductile deformation.
Solution Approach 2:
The invention applies local quality by creating an asymmetric gap configuration where the gap between distal end portions and the lower cover is smaller than the gap to the upper cover. This localized geometric modification ensures that collision occurs only with the lower cover, concentrating the frequency adjustment action at the appropriate location while preserving the metal film integrity.
2Manufacturing precision
If the distal end portions of vibration arms are caused to collide with both upper and lower covers, then frequency adjustment can be achieved, but the amplitude of vibration is restricted and weight change is minimal
Solution Approach 1:
The invention inverts the conventional dual-collision approach by designing the resonator to collide exclusively with the lower cover. The asymmetric gap configuration ensures that the lower cover is positioned closer to the distal end portions, making it the sole collision target during vibration. This eliminates the time-wasting dual-collision mechanism while maintaining precise frequency adjustment capability.
3Strength
If a metal film is formed on the upper cover side of the distal end portions, then the structure is complete, but collision with the upper cover causes ductile deformation without effective weight reduction
Solution Approach 1:
The invention resolves this contradiction by inverting the collision target from the upper cover to the lower cover. The asymmetric gap design ensures that the lower cover receives the distal end portions during vibration, enabling effective material removal from the metal film while the upper cover remains non-contacting, thus preserving metal film integrity where it is formed.
Solution Approach 2:
The invention applies local quality by creating different gap sizes at different locations: a smaller gap between distal end portions and the lower cover, and a larger gap to the upper cover. This localized geometric modification ensures collision occurs only at the lower cover location, enabling precise weight adjustment while preserving the metal film at the upper cover interface.
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 configuration enables precise and efficient frequency adjustment, reducing the time required for the process while maintaining mechanical strength and preventing ductile fracture of the metal films, thereby improving productivity and accuracy.
Implementation Method 1
a resonator having vibration arms that are held and configured to vibrate in the interior space
Implementation Method 2
adjusting the frequency of a resonator by causing the distal end portions of excited vibration arms to collide with a lower cover and an upper cover
Data Source
AI summary
A resonance device is provided that includes a lower cover; an upper cover coupled to the lower cover; and a resonator that has vibration arms that generate bending vibration in an interior space provided between the lower cover and the upper cover. Moreover, the vibration arms have distal ends provided with metal films on a side that faces the upper cover, and a gap is provided between the distal ends of the vibration arms and the upper cover that is larger than a gap between the distal ends of the vibration arms and the lower cover.