公开(公告)号：DE3106818A1

公开(公告)日：1982-09-09

申请号：DE3106818

申请日：1981-02-24

Applicant: BASF AG

Inventor： RENNIG ALFRED ,  RETTING WOLFGANG DR DIPL PHYS

IPC: G01N21/23 ,  G01N21/86 ,  G01N21/41

Abstract: Method of continuously determining multiaxial orientation states of stretched films or panels by means of their main birefringence values, in which a) three laser beam paths, produced by three lasers or by dividing one laser beam, are used, one of which passes through the film perpendicularly and the two others pass through it at an angle such that the planes of inclination are perpendicular to the plane of the film and contain the two main orientation directions, b) the phase differences of the laser-beam intensities are continuously measured after passing through the film, a 1/4 plate and a rotating analyzer, and c) the three main birefringence values of the film are continuously determined from the three phase differences allowing for the two angles of inclination of the inclined laser beams and the thickness of the film determined by another method.