Patent ID: 6798572
Filing Date: 2004-09-28
Classification: B29C,B29D,B29L,G03B

Abstract:
A transmission screen sheet which is given a large number of lens-like forms on the surface like ridges and has a thickness of 0.1 to 2.0 mm, wherein (i) the sheet is formed from a thermoplastic resin whose inclination (W) obtained from the relationship between melt viscosity (Y) and load (X) satisfies the following expression (1) when the melt viscosity is in the range of 102 to 103 PaÂ·s, and (ii) the lens-like forms change in height substantially non-stepwise from the center portion or a portion near the center portion to the end portions of the sheet in a direction perpendicular to the ridges:2Ã—10âˆ’2&lE;W&lE;6Ã—10âˆ’2â€ƒâ€ƒ(1) wherein W is represented by the following equation:W=âˆ’(log Y/X) wherein X is a load (MPa) and Y is the melt viscosity (PaÂ·s) of the resin.