Patent ID: 8551249

Claim:
A cassette for supporting a length of a film substrate during a gaseous vapor deposition process, the film substrate having a predetermined width dimension at the gaseous deposition temperature, the cassette comprising: a central shaft having an axis therethrough; a first and a second end plate, each end plate being mounted to the shaft, each end plate comprising a central hub from which radiate a plurality of angularly spaced spokes, the spokes of each end plate having an interior surface that lies on a reference plane, the reference plane being oriented substantially perpendicular to the axis of the shaft, the interior surfaces of spokes of the end plates being confrontationally disposed and spaced apart by a predetermined interspoke spacing, each end plate having a spiral rib mounted to the interior surface of the spokes thereof, each spiral rib having a predetermined number of uniformly spaced turns and a predetermined pitch associated therewith, the spaces between adjacent turns of the spiral rib defining a spiral groove on each end plate able to accept an edge of a film, each spiral groove having a first end and a second end, the spiral groove in one end plate facing toward the spiral groove in the other end plate with the first and second ends of each respective groove being axially aligned, each rib having a cross sectional configuration in a radial plane containing the axis of the shaft, the cross sectional configuration exhibiting substantially linear major edges, each rib having a predetermined width dimension measured from the interior surface of the spoke on which the rib is mounted in a direction parallel to the axis of the shaft, a predetermined average thickness dimension measured in a radial direction with respect to the axis of the shaft, and a width-to-average-thickness aspect ratio of at least 2:1, wherein the interspoke spacing is at least three hundred millimeters (300 mm) and is greater than the width dimension exhibited by a film substrate at a gaseous deposition temperature, and the width dimension of the rib on each end plate is between about 0.5% to about 2.0% of the interspoke spacing.