| abstract |
A film having excellent optical homogeneity, which is suitably used as an optical film in an image display apparatus, and a method for producing the same. In addition, an evaluation method capable of evaluating optical homogeneity of a film with higher precision than a conventional evaluation method is provided. The film of the present invention is a cast film containing a resin having a weight average molecular weight of 200,000 or more and is a film obtained by subjecting a projection image obtained by a projection method to a Fourier transform using the film, v are referred to as a line profile h and a line profile v, respectively, and in the projection method, a background image obtained without using the film is subjected to a Fourier transform to obtain a direction h 'and a direction (h-h ') obtained by subtracting the line profile h' from the line profile h is represented by Y mh , and the maximum intensity of the line profile (h-h ') obtained by subtracting the line profile h' The median value of the total frequency in the line profile that was blank corrected from the frequency representing the intensity Y mh X cen As the X max X mh value minus, and the maximum intensity from the line profile, v-line profile v 'a line profile (v-v obtained by subtracting ") as Y mv and blank corrected from the frequency showing the maximum intensity Y mv when the X max value obtained by subtracting the middle value X cen of the total frequency of the line profile that X mv, Y mh and Y mv are all less than 30, Y mh, Y mv, X mh and X mv will meet specific expression of . |