29-10-2020 дата публикации
Номер: US20200338592A1
Принадлежит:
The teachings of the present disclosure enable the manufacture of one or more piezoelectric micromachined ultrasonic transducers (PMUTs) having a resonant frequency of a specific target value and/or substantially matched resonant frequencies. In accordance with the present disclosure, a flexible membrane of a PMUT is modified to impart a desired parameter profile for stiffness and/or mass to tune its resonant frequency to a target value. The desired parameter profile is achieved by locally removing or adding material to regions of one or more layers of the flexible membrane to alter its geometric dimensions and/or density. In some embodiments, material is added or removed non-uniformly across the structural layer to realize a material distribution that more strongly affects membrane stiffness than mass. In some embodiments, material having a specific residual stress is added to, and/or removed from, the membrane to define a desired modal stiffness for the membrane. 117-. (canceled)18. A method comprising:{'sub': '0', 'b': '500', 'establishing an acceptable range of resonant frequencies (Δf) for a plurality of piezoelectric micromachined ultrasonic transducer (PMUTs) ();'}{'b': 204', '1', '1', '1, 'providing the plurality of PMUTs such that each PMUT of the plurality thereof includes a membrane () that is characterized by a first design that includes a first lateral dimension (D), a center (C), and a periphery (P), wherein each PMUT of the plurality thereof has a resonant frequency that is based on at least one of the stiffness and mass of its respective membrane;'}{'sub': n', 'n, 'b': 1', '1, 'determining a preliminary value (f-, through f-M,N) for the resonant frequency of each PMUT of the plurality thereof;'}{'b': 502', '1', '1', '1', '1, 'sub': 'n', 'determining a first desired resonant-frequency change for a first PMUT (-,) of the plurality thereof, wherein the first desired resonant-frequency change is based on the acceptable range of resonant frequencies, the ...
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