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:
Nov. 15, 1994
Filed:
Nov. 13, 1990
Kevin L Miller, Loveland, CO (US);
Eric M Krug, Loveland, CO (US);
James A Imthurn, Rathdrum, ID (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A computer memory backup device which utilizes standardized computer tape cartridges is disclosed. The focus of the invention is upon the techniques for ascertaining the appropriate placement of such cartridges to allow operation of the computer memory backup device. The device being connected to a computer allows for the determination of a cartridge presence through the use of an optical sensor mechanism. The sensor mechanism includes a light emitting diode (l.e.d.), light pipe and phototransistor. During any time that the cartridge is not in the computer memory device or improperly or incompletely inserted the electromagnetic radiation emitted by the l.e.d. will be directed by the light pipe to the phototransistor. In this manner a negative determination is correctly made. When the cartridge is correctly and completely inserted, the pathway of the electromagnetic radiation is blocked between the light pipe and the phototransistor. In this manner a positive determination is correctly made. To enhance the accuracy of the disclosed device, time domain filtering is used to screen erroneous electromagnetic radiation from causing an incorrect cartridge in determination.