US 11,798,745 B2
Multilayer ceramic electronic device and method for manufacuting same
Ryo Ono, Tokyo (JP); Tetsuhiko Fukuoka, Tokyo (JP); Shoji Kusumoto, Tokyo (JP); and Akihiko Kono, Tokyo (JP)
Assigned to TAIYO YUDEN CO., LTD., Tokyo (JP)
Filed by TAIYO YUDEN CO., LTD., Tokyo (JP)
Filed on Jul. 14, 2020, as Appl. No. 16/928,425.
Claims priority of application No. 2019-130956 (JP), filed on Jul. 16, 2019; and application No. 2020-076431 (JP), filed on Apr. 23, 2020.
Prior Publication US 2021/0020379 A1, Jan. 21, 2021
Int. Cl. H01G 4/30 (2006.01); H01G 4/12 (2006.01); H01G 4/248 (2006.01)
CPC H01G 4/30 (2013.01) [H01G 4/12 (2013.01); H01G 4/248 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A multilayer ceramic electronic device, comprising:
a ceramic functional part having a generally rectangular shape in which a plurality of ceramic dielectric layers and a plurality of internal electrodes are laminated alternately in a vertical direction;
a pair of cover parts that cover the functional part from top and bottom, respectively; and
a pair of side margin parts covering side surfaces of the functional part, respectively,
wherein in a plan view, an uppermost internal electrode among the plurality of internal electrodes spans an entire width of the functional part, and has an end portion reaching and terminating at one of the side surfaces of the functional par that are covered by the side margin parts, the end portion being curved downward to satisfy 2 μm≤a≤20 μm, 20 μm≤b≤50 μm and 0.1≤a/b≤0.4, where a is a dimension of the curved end portion in the vertical direction in a cross section taken along a plane perpendicular to the side surfaces, and b is a dimension of the curved end portion in a horizontal direction in said cross section, and
wherein in the plan view, a lowermost internal electrode among the plurality of internal electrodes spans the entire width of the functional part, and has an end portion reaching and terminating at one of the side surfaces of the functional part that are covered by the side margin parts, the end portion of the lowermost internal electrode being curved upward to satisfy 2 μm ≤a′ <20 μm, 20 μm≤b′≤50 μm and 0.1 ≤a′/b′ <0.4, where a′ is a dimension of the curved end portion of the lowermost internal electrode in the vertical direction in the cross section taken along the plane perpendicular to the side surfaces, and b′ is a dimension of the curved end portion of the lowermost internal electrode in the horizontal direction in said cross section,
wherein a top surface of each of the pair of side margin parts has a curved end portion that is curved downwardly in parallel to the vertical direction, and a bottom surface of each of the pair of side margin parts has a curved end portion that is curved upwardly in parallel to the vertical direction, the curved end portions of the uppermost internal electrode and the lowermost internal electrode respectively being less curved than the curved end portions of each of the pair of side margin parts,
wherein the plurality of internal electrodes respectively have end portions that reach and terminate at the side surfaces of the functional part, and the end portions thereof are curved progressively greatly downwardly or upwardly towards the uppermost internal electrode and the lowermost internal electrode, respectively, and
wherein the plurality of internal electrodes respectively have other end portions that reach and terminate at one of end surfaces of the functional part that are orthogonal to the side surfaces thereof, said other end portions of the plurality of internal electrodes being substantially horizontally flat, having no curved portion in the vertical direction.