Carl-zeiss-stiftung

Microm Laborgerate Gmbh

Christian Niesporek

Wolfgang Jakobi

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.

Cryostatic microtome

A microtome (2) with a sample holder (51) for a sample (22) to be thinly sectioned and with a knife holder (12) for a cutting knife (10) is described, wherein the sample holder (51), for performing a cutting movement (arrow 54) relative to the knife holder (12), can be driven in a first spatial direction (arrows 54, 56) by means of a first drive device (53), and for performing a coarse adjustment and a section thickness adjusting movement in a second spatial direction (arrow 24) perpendicular to the first spatial direction (54, 56) by means of an electrical second drive device (50). In the vicinity of the cutting knife (10), for defined delimitation of the coarse adjustment movement of the sample holder (51) in the second spatial direction, a delimiting device (20) is provided, which is connected over control means (44), preferably an electronic control, with the electrical second drive device (50).

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Wiesloch, Germany

Christian Niesporek