US 12,237,827 B2
Solidly-mounted transversely-excited film bulk acoustic filters with multiple piezoelectric plate thicknesses
Ventsislav Yantchev, Sofia (BG); Patrick Turner, San Bruno, CA (US); and Robert B. Hammond, Santa Barbara, CA (US)
Assigned to MURATA MANUFACTURING CO., LTD., Nagaokakyo (JP)
Filed by Murata Manufacturing Co., Ltd., Nagaokakyo (JP)
Filed on Dec. 28, 2021, as Appl. No. 17/563,936.
Application 17/563,936 is a continuation in part of application No. 17/351,201, filed on Jun. 17, 2021, granted, now 11,876,498.
Application 17/351,201 is a continuation of application No. 16/988,213, filed on Aug. 7, 2020, granted, now 11,201,601, issued on Dec. 14, 2021.
Application 16/988,213 is a continuation in part of application No. 16/438,121, filed on Jun. 11, 2019, granted, now 10,756,697, issued on Aug. 25, 2020.
Application 16/438,121 is a continuation in part of application No. 16/230,443, filed on Dec. 21, 2018, granted, now 10,491,192, issued on Nov. 26, 2019.
Claims priority of provisional application 62/904,152, filed on Sep. 23, 2019.
Claims priority of provisional application 62/892,980, filed on Aug. 28, 2019.
Claims priority of provisional application 62/753,815, filed on Oct. 31, 2018.
Claims priority of provisional application 62/748,883, filed on Oct. 22, 2018.
Claims priority of provisional application 62/741,702, filed on Oct. 5, 2018.
Claims priority of provisional application 62/701,363, filed on Jul. 20, 2018.
Claims priority of provisional application 62/685,825, filed on Jun. 15, 2018.
Prior Publication US 2022/0123730 A1, Apr. 21, 2022
Int. Cl. H03H 9/56 (2006.01); H03H 3/02 (2006.01); H03H 3/04 (2006.01); H03H 9/02 (2006.01); H03H 9/17 (2006.01); H03H 9/205 (2006.01); H03H 9/54 (2006.01)
CPC H03H 9/568 (2013.01) [H03H 3/02 (2013.01); H03H 3/04 (2013.01); H03H 9/02015 (2013.01); H03H 9/02157 (2013.01); H03H 9/02228 (2013.01); H03H 9/174 (2013.01); H03H 9/205 (2013.01); H03H 9/54 (2013.01); H03H 9/564 (2013.01); H03H 9/566 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A filter device comprising:
a substrate;
a piezoelectric layer having a first portion that has a first thickness and a second portion that has a second thickness less than the first thickness;
an acoustic Bragg reflector between a surface of the substrate and a back surface of the piezoelectric layer; and
a conductor pattern on front surfaces of the first and second portions of the piezoelectric layer, the conductor pattern comprising:
a first interdigital transducer (IDT) with interleaved fingers on the first portion, and
a second IDT with interleaved fingers on the second portion,
wherein at least a portion of interleaved fingers of each of the first IDT and the second IDT have a width that is greater than or equal to 0.2 times a pitch of the respective IDT and less than or equal to 0.3 times the pitch of the respective IDT, and
wherein the pitch of the interleaved fingers is a center-to-center spacing between two adjacent interleaved fingers that extend from different busbars of the conductor pattern.