US 12,241,738 B2
Detection signal processing apparatus and detection signal processing method for eddy current sensor
Hiroto Yamada, Tokyo (JP); Taro Takahashi, Tokyo (JP); and Hiroaki Shibue, Tokyo (JP)
Assigned to EBARA CORPORATION, Tokyo (JP)
Filed by EBARA CORPORATION, Tokyo (JP)
Filed on Jun. 13, 2022, as Appl. No. 17/839,350.
Claims priority of application No. 2021-106668 (JP), filed on Jun. 28, 2021.
Prior Publication US 2022/0412715 A1, Dec. 29, 2022
Int. Cl. G01B 7/06 (2006.01); B24B 37/005 (2012.01)
CPC G01B 7/105 (2013.01) [B24B 37/005 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A detection signal processing apparatus configured to process a detection signal of an eddy current sensor having an excitation coil configured to form an eddy current in an object to be detected, a first detection coil configured to detect the eddy current formed in the object to be detected, and a dummy coil and/or a second detection coil configured to detect the eddy current, wherein the excitation coil is electrically independent from the first detection coil and the dummy coil and/or the second detection coil, the apparatus comprising:
a first converter configured to convert a first analog signal output by the first detection coil into a first digital signal, the first converter configured such that the first analog signal is input into the first converter without passing through a bridge circuit and a synchronous detection circuit;
a second converter configured to convert a second analog signal output by the dummy coil into a second digital signal, and/or a third converter configured to convert a third analog signal output by the second detection coil into a third digital signal; and
a detector which is a digital signal processing circuit configured to detect the first digital signal, and the second digital signal and/or the third digital signal.