Patent ID: 11885734
Assignee: DAI NIPPON PRINTING CO., LTD.
Field: Measurement (Instruments)
Classification: CPC C  G  B  H | IPC G

Claim 0:
1. An optical plastic film satisfying the following conditions 1 and 2:
<Condition 1>
when a large sample with a size of 200 mm×300 mm is cut out from a plastic film, the large sample is divided into 30 small samples of 40 mm×50 mm, a region of 30 mm×40 mm obtained by excluding 5 mm from each edge of each small sample is subdivided into 47,000 or more regions, and an in-plane phase difference of each subdivided region is then measured, a percentage of small samples in which an average of the in-plane phase difference of each region measured is 300 nm or more and 1,200 nm or less, among the 30 small samples is 70% or more; and
<Condition 2>
when the 30 small samples are processed in the same manner as in condition 1 and an angle of slow axis of each subdivided region of each small sample is measured, a percentage of small samples in which a standard deviation G calculated from the angle of slow axis of each region measured is 0.8 degrees or more and 20.0 degrees or less, among the 30 small samples is 70% or more.