Resonator Frame Spacing to Limit Charge-Induced Frequency Drift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing resonators with insulating films on their frames can be electrified due to electric fields or pyroelectric effects, leading to changes in the resonant frequency due to Coulomb forces generated by electric charges, which affects the spring constant and stability of the vibration portion.
Innovation Solution
A resonance device design where the inner side surface of the insulating film in the holding portion is positioned at a specific distance from the side wall, reducing the influence of electric charges on the resonant frequency, and incorporating a configuration that minimizes the overlap between the metal layer and conductive film to reduce electrostatic hindrance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating film is formed on the frame to provide electrical insulation, then electrical insulation is improved, but the insulating film becomes electrified due to electric fields or pyroelectric effects, generating Coulomb forces that change the spring constant and resonant frequency
Solution Approach 1:
A ground electrode is introduced as an intermediary between the electrified insulating film and the vibration portion. This ground electrode provides a discharge path for electric charges, preventing Coulomb forces from acting on the vibration portion while maintaining the electrical insulation function of the insulating film.
Solution Approach 2:
The ground electrode is positioned to preemptively neutralize electric charges on the insulating film before they can generate harmful Coulomb forces. By providing a discharge path in advance, the system prevents frequency drift rather than correcting it after occurrence.
2Volume of moving object
If the insulating film is positioned close to the vibration portion to reduce device size, then device compactness is improved, but the influence of electric charges on the resonant frequency increases
Solution Approach 1:
The ground electrode serves as a mediator that allows the insulating film to be positioned close to the vibration portion for compactness while preventing electric charges from affecting the resonant frequency. The ground electrode intercepts charges before they can exert Coulomb forces on the nearby vibration portion.
3Manufacturing precision
If additional etching is performed to adjust the resonant frequency, then frequency accuracy is improved, but the insulating film becomes electrified due to ion beam irradiation, causing frequency drift
Solution Approach 1:
The ground electrode acts as a protective intermediary during the frequency adjustment process. When ion beam etching is performed, any electric charges generated on the insulating film are immediately discharged through the ground electrode, preventing frequency drift that would otherwise occur during or after the adjustment 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
This design effectively reduces the impact of electric charges on the resonant frequency, enhancing the stability and accuracy of the resonator's frequency by maintaining the spring constant and preventing frequency changes caused by electrostatic forces.
Implementation Method 1
an insulating film of the frame may be electrified due to, for example, an electric field generated during thin film formation
Implementation Method 2
a Coulomb force (e.g., an electrostatic force) is generated by the electric charge at the insulating film
Implementation Method 3
when such a frequency adjusting method using ion beams described in Patent Document 1 is used in existing resonators, an insulating film of the frame may be electrified due to the frame being irradiated with an ion beam
Implementation Method 4
a Coulomb force (e.g., an electrostatic force) is generated by the electric charge at the insulating film
Implementation Method 5
when a pyroelectric material is used for an insulating film of the frame, an electric charge is generated at the interface of the insulating film due to a pyroelectric effect caused by temperature changes
Data Source
AI summary
A resonance device is provided for reducing the influence on the resonant frequency of the resonance device of the electric charge borne by an insulating film of a frame. The resonance device includes a resonator including a vibration portion and a frame disposed in at least a part of a vicinity of the vibration portion. The frame includes a holding body and an insulating film, with the holding body holding the vibration portion to vibrate and the insulating film being formed above the holding body. A lower cover is provided having a recess forming at least a part of a space in which the vibration portion vibrates. An inner side surface of the insulating film is disposed at a first distance from an inner surface of a side wall defining the recess.