US 12,145,839 B1
Drop resistant MEMS actuator-imager assembly package
Faez Ba-Tis, East York (CA); Ahmed Galaom, East York (CA); Ali Banss, East York (CA); and Hui Zuo, Richmond Hill (CA)
Filed by Sheba Microsystems Inc., North York (CA)
Filed on Mar. 4, 2024, as Appl. No. 18/595,030.
Int. Cl. B81B 7/00 (2006.01)
CPC B81B 7/0058 (2013.01) [B81B 2201/034 (2013.01); B81B 2203/0163 (2013.01); B81B 2203/0353 (2013.01); B81B 2203/04 (2013.01); B81B 2207/11 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A MEMS actuator-imager assembly package, comprising:
a) an IR bracket or a glass holder;
b) an IR filter or a glass cover attached to the IR filter or the glass holder;
c) a MEMS actuator comprising a moving part, a fixed part and a plurality of mechanical springs; the moving part comprises of a rotor having a number of MEMS moving electrodes forming a first polarity of the MEMS actuator and attached to the fixed part via the plurality of mechanical springs; the fixed part of the MEMS actuator comprises of a substrate supporting a number of MEMS fixed electrodes forming a second polarity of the MEMS actuator;
d) a first set of flexible stoppers attached to the rotor that are spaced apart from a fixed outer periphery with a certain gap g1 and a stiffness K1;
e) a second set of flexible stoppers attached to the rotor that are spaced apart from the fixed outer periphery with a certain gap g2 that is larger than the g1 gap and have a stiffness K2 that is larger than or equal to the K1 stiffness;
f) a set of hard stoppers attached to the rotor and spaced with a gap g3 that is larger than g1 and g2 gaps;
g) a set of protrusions that extend vertically at a backside of the rotor and penetrate through the substrate via a through hole forming a negative z-axis mechanical stoppers;
h) an image sensor attached to the rotor of the MEMS actuator;
i) a MEMS housing with a cavity sized to fit and receive the MEMS actuator; the MEMS housing contains a number of cavities placed under the negative z-axis mechanical stoppers and have a depth larger than the vertical stroke of the actuator along the negative direction of the z-axis;
j) a circuit board, with a cut-out sized to fit and receive the image sensor; wherein the MEMS housing is attached to the circuit board from the backside; the circuit board may contain a MEMS driving circuit that provides a voltage input to operate the MEMS actuator and overlaps with the moving rotor;
whereby the first and second flexible stoppers along with the hard stoppers engage in a sequential manner with the moving mass in the presence of mechanical shocks along the four directions of the in-plane axes (x and y) bringing the moving mass to a complete stop; in the presence of mechanical shock along the positive and negative directions of the z-axis, the negative direction of the z-axis stoppers act to stop the moving mass along the negative z-axis direction by hitting the bottom surface of the MEMS housing cavities; the circuit board works as a flexible mechanical stopper for the moving mass along the positive direction of the z-axis.