The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 18, 2006
Filed:
Jun. 17, 2002
Takumi Hayashi, Tokyo, JP;
Shinichi Kawai, Tokyo, JP;
Hiroshi Hatanaka, Tokyo, JP;
Yamatake Corporation, Tokyo, JP;
Abstract
A high-frequency oscillation proximity sensor with an improved detection sensitivity uses, as a detection coil, a two-thread coil formed of substantively two coil conductors joined together at their first ends to form a joint connection end and twisted together, one of the two coil conductors being used as a resonance circuit coil Land the other as a copper resistance compensation coil L, and comprises a drive circuitfor supplying a drive current to the joint connection end of the two-thread coil to thereby drive the detection coil to oscillate, a bufferfor taking out an oscillating output voltage generated at the joint connection end of the two-thread coil, and a phase shift circuitfor turning the phase of the oscillating output voltage taken out by the buffer by a predetermined angle and feeding it back to the copper resistance compensation coil to thereby negate the copper resistance of the two-thread coil. The drive circuit comprises a nonlinear amplifierfor changing the amplitude of the oscillating voltage generated at the two-thread coil in multiple stages to thereby impart a soft oscillation characteristic to a high-frequency oscillation circuit comprising the nonlinear amplifier and the two-thread coil.