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:
Oct. 06, 1992
Filed:
Sep. 15, 1989
Hitachi, Ltd., Tokyo, JP;
Abstract
An apparatus for measuring the clearance between a recording transducer and a recording medium, which includes at least a conductive layer or conductive section, comprises a field electron emission electrode section disposed on the recording transducer, a voltage source for applying a voltage, which is greater at least in its peak value than the work functions of the electrode section and the conductive layer or conductive section of the recording medium, between the electrode section and the conductive layer or conductive section of the recording medium, a current measuring device for measuring the current flowing from the voltage source to the electrode section and the conductive layer or conductive section of the recording medium, and a computation processor for calculating the distance between the electrode section and the recording medium from the value of current measured by the current measuring device. A recording apparatus having the recording transducer clearance measuring apparatus is designed to support the recording transducer, which records and reproduces data on the recording medium, with a recording transducer supporting device through an advance/retract mechanism and to drive the mechanism in accordance with the distance calculated by the computation processor so as to adjust appropriately the clearance between the recording transducer and recording medium. A control method for the recording apparatus alters the operational condition of the recording apparatus if the clearance has exceeded a certain preset value.