US 12,123,714 B2
Output signal processing circuit for eddy current sensor and output signal processing method for eddy current sensor
Hiroto Yamada, Tokyo (JP); Taro Takahashi, Tokyo (JP); Hiroaki Shibue, Tokyo (JP); Atsushi Abe, Tokyo (JP); and Shinpei Tokunaga, Tokyo (JP)
Assigned to EBARA CORPORATION, Tokyo (JP)
Filed by EBARA CORPORATION, Tokyo (JP)
Filed on Nov. 8, 2023, as Appl. No. 18/504,301.
Application 18/504,301 is a division of application No. 17/122,301, filed on Dec. 15, 2020, granted, now 11,852,472.
Claims priority of application No. 2019-226547 (JP), filed on Dec. 16, 2019; and application No. 2019-226549 (JP), filed on Dec. 16, 2019.
Prior Publication US 2024/0077297 A1, Mar. 7, 2024
Int. Cl. G01B 7/06 (2006.01); H01L 21/67 (2006.01)
CPC G01B 7/105 (2013.01) [H01L 21/67253 (2013.01)] 3 Claims
OG exemplary drawing
 
1. An eddy current sensor output signal processing circuit that processes a first detection signal and a first dummy signal output by an eddy current sensor including a first exciting coil capable of accepting an excitation signal as input and generating a first magnetic field, a first detecting coil capable of detecting the first magnetic field and outputting the first detection signal, and a first dummy coil capable of detecting the first magnetic field and outputting the first dummy signal, the output signal processing circuit comprising:
a first resistance bridge circuit capable of outputting a difference between the first detection signal and the first dummy signal as a first difference signal;
a first generator circuit capable of generating a first noise reduction signal for reducing noise from any of the excitation signal, the first detection signal, the first dummy signal, and the first difference signal; and
a first adder circuit capable of adding the first noise reduction signal generated in the first generator circuit to the first difference signal to generate a first noise-reduced signal in which noise included in the first difference signal is reduced.