| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical film having negative stress birefringence though having positive oriented birefringence. <P>SOLUTION: The optical film comprises a composite film comprising a urethane polymer and a vinyl polymer and has a photoelastic coefficient of less than 0 m<SP>2</SP>/N and oriented birefringence: nx-ny of at least 5×10<SP>-5</SP>, where nx is a refractive index in the direction of the X-axis, that is, the direction having the maximum in-plane refractive index of the composite film, and ny is the refractive index in the direction of the Y-axis, that is, the direction rectangularly crossing the X-axis. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
