US 12,695,436 B2 · Density-modulated phononic membranes

Abstract

The invention relates to a mechanical oscillator device comprising an unsupported membrane with a multitude of discrete mass elements distributed to form Phononic crystal cells in the form of regions of additional mass each comprising a plurality of mass elements. The phononic crystal structure has a defect for confining a mechanical oscillation mode having a resonance frequency, f, with the mass elements have a smallest lateral dimension of less than 1/10 of a wavelength of the mechanical oscillation mode. The invention is based on a distribution of tiny additional mass elements providing a periodic density contrast pattern to create the bandgap. This approach keeps the tensile stress uniform which ensures perfect overlap between the tensile stress distribution and mode-shape. This again reduces the damping and thus allows for very high quality factors, Q.

Claims16

Dependent claims

A mechanical oscillator device comprising:

a thin film on a supporting substrate, wherein the supporting substrate is shaped to expose an area of the thin film to form an unsupported membrane;
wherein the membrane comprises periodic pattern of regions of additional mass, wherein:
the periodic pattern of the regions of additional mass provides a phononic crystal structure on the membrane wherein each region of additional mass is a unit cell in the phononic crystal structure and
the phononic crystal structure exhibits a defect for confining a mechanical oscillation mode having a resonance frequency, f, and corresponding wavelength λ and
wherein the unit cell is formed by a distribution of discrete mass elements;
and a minimum lateral dimension, d, of the mass elements is less than 1/10 of the wavelength of the mechanical oscillation mode.

3 more elements

Dependencies are inferred from the claim text.

Density-modulated phononic membranes

Life of this patent

Density-modulated phononic membranes

Life of this patent

Abstract

Claims16