US Patent No. 10,335,897

LASER ABLATION OF ACCELEROMETER PROOF MASS


Patent No. 10,335,897
Issue Date July 02, 2019
Title Laser Ablation Of Accelerometer Proof Mass
Inventorship William Goodman, Sunnyvale, CA (US)
Assignee Applied Physics, Inc., Mountain View, CA (US)

Claim of US Patent No. 10,335,897

1. A method for producing a proof-mass assembly, comprising:forming a proof mass with a curved flapper hingedly supported at a straight end by a bifilar flexure that extends radially inwardly from a support ring, wherein one side of the bifilar flexure comprises a pair of adjacent flexure arms spaced apart by a window;
scanning a femtosecond laser on the flexure arms over a plurality of passes to gradually thin bifilar flexure regions on a first side of the flexure arms;
feathering with the femtosecond laser in areas where the flexure arms connect to the curved flapper or reed and producing a gradual transition from a thick to a thin section; and
periodically reducing femtosecond laser output to minimize damage from laser scanning and maximize bifilar flexure strength until the bifilar flexure arms reach a predetermined thickness to form the proof-mass assembly.