Patent ID: 8721933
Filing Date: 2014-05-13
Classification: B29C,B29D,B32B,Y10T

Abstract:
1. A manufacture method of an optical sheet made of a transparent thermoplastic resin sheet as a surface thereof a regular geometric design working is performed, the optical sheet manufacture method comprising: performing a geometric design working on the resin sheet at a temperature not lower than a glass transition temperature of the resin sheet, by using a metal endless working belt formed with a geometric design on a surface thereof, wherein the temperature not lower than a glass transition temperature is not lower than Tg+60° C. and not higher than Tg+90° C., where Tg (° C.) is the glass transition temperature of the resin sheet; rapidly cooling the resin sheet on which the geometric design working is performed to a temperature lower than the glass transition temperature, wherein the resin sheet is cooled at a cooling speed not slower than 5° C./sec and not higher than 40° C./sec; and detaching the rapidly cooled resin sheet from the metal endless working belt, wherein the resin sheet is made of transparent crystalline resin selected from the group consisting of PET, PEN, and a mixture or copolymer of PET and PEN and has a crystallization rate of 20% or less when the resin sheet is detached from the metal endless working belt.