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:
Jun. 09, 1998
Filed:
Aug. 01, 1996
Carl-Zeiss-Stiftung, Heidenheim, DE;
Abstract
A cryostatic microtome with an automatic approach of the preparation automatically stops the feed movement between the microtome knife and a frozen preparation towards each other upon a mechanical contact between the knife and the preparation. An electrical voltage of a few volts is applied between the microtome knife and the preparation. A small current which appears, due to the intrinsic conductivity of the preparation, upon mechanical contact between the preparation and the microtome knife, and a smaller voltage drop at the preparation resulting therefrom, is current amplified by means of a preamplifier connected as an impedance converter and subsequently measured. The feed movement between the preparation and the microtome knife is automatically stopped when the voltage at the amplifier output falls below a predefined threshold voltage. The preset threshold voltage is temperature dependent and is calculated by a control processor corresponding to the temperature of the cryostat, based on a function and function coefficients. The temperature dependence of the threshold voltage ensures a reliable and precise approach of the preparation throughout the entire temperature range usual in cryomicrotomy.