OPTICAL FEATURES


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TOP & BOTTOM WINDOWS

•  All stages feature a top aperture and many stages feature a transmission aperture and a bottom window

•  The top viewing window consists of an opening in the top cover and the bottom window consists of an opening in the bottom frame

•  Top and bottom windows are secured with a flat rubber O-ring on the interior side and a metal screwing retaining ring on the exterior side

•  The top and bottom aperture magnitude is the effective diameter of the window, limited on the outer edge by the retaining ring and the rubber O-ring

•  This aperture magnitude is typically 4 mm less than the window disc diameter

•  Different window sizes are available as options. 

•  Removable and interchangeable windows accommodate the full spectrum of light sources and techniques

•  Heat loss scales with window area. Windows are circular and sized according to application to balance maximum viewing angle and minimum heat loss


OPTICAL PATH

•  The optical path on stages is through a top viewing window, a transmission aperture in the block, and a bottom window

•  The top viewing angle is the maximum angle made from the edges of the window retaining ring and the center of the thermal block top surface

•  The top viewing angle depends on the chamber height and the window diameter

•  The top viewing angle is double the angle from normal

•  The transmission aperture is the minimum diameter of the cylindrical hole through the heating block

•  Standard transmission aperture is 2 mm diameter with options of 5 mm or 8 mm diameters

•  The transmission angle is the maximum angle made from the edges of the transmission aperture and the center of the thermal block bottom surface


OBJECTIVE & CONDENSER

•  The minimum objective working distance is the distance between the top surface of the thermal block and the outer surface of the viewing window

•  Sample height reduces the minimum objective working distance

•  If the actual objective working distance is less than the minimum working distance, a focused image is not achieved

•  Removing the outer windows results in shorter working distances, but compromises sample thermal isolation and risks exposing the lenses to damaging heat

•  The minimum condenser working distance is the distance between the bottom surface of the thermal block and the outer surface of the bottom window

•  Longer working distance condensers are necessary to focus images through the thermal block using Kohler illumination in modern microscopes


INTEGRATED WINDOW DEFROST

•  Some models feature top viewing window defrost mechanism for use with inert or dry gas supply

•  One option is an integrated channel in the top cover with a hose port

•  Another option is an externally mounted hose holder that allows easy positioning of the hose tip anywhere on the window

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