| 摘要 |
PROBLEM TO BE SOLVED: To provide heat treatment equipment for producing a heat-resistant thermoplastic resin film which has small birefringence, that is, an optical phase difference, reduces variations in a width direction, and has excellent optical isotropy. SOLUTION: This heat treatment equipment, which comprises at least a wind-off part, an air-floating type heating furnace and a take-up part, heat-treats the roll-shaped heat-resistant thermoplastic resin film between two rolls, which are arranged at an entrance of the heating furnace and an exit thereof, respectively, by applying tension in the direction of the treatment of the film. The heat treatment equipment is characterized in that the diameter of at least either of the above rolls is smoothly varied in the width direction of the roll in the range of an average diameter plus or minus 10%. COPYRIGHT: (C)2004,JPO
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