17-05-2012 дата публикации
Номер: US20120120356A1
Принадлежит:
An optical film having a desired wavelength dispersion characteristic, a low photoelastic coefficient and a desired Nz coefficient. 1. An optical film which is formed from a copolymer and meets the following conditions (i) to (v):(i) the thickness (d) is 20 to 80 μm; [{'br': None, 'i': R', 'R, '0.6<(450)/(550)<1\u2003\u2003(1)'}, {'br': None, 'i': R', 'R, '1.01<(650)/(550)<1.40\u2003\u2003(2)'}], '(ii) the following formulas (1) and (2) are satisfied(R(450), R(550) and R(650) are retardations within the plane of the film at wavelengths of 450 nm, 550 nm and 650 nm, respectively);(iii) R(550) is 120 to 160 nm (R(550) is a retardation within the plane of the film at a wavelength of 550 nm);{'sup': '−3', 'claim-text': {'br': None, 'i': n=R', 'd×, 'sup': '3', 'Δ(550)/(10)\u2003\u2003(3)'}, '(iv) the birefringence (Δn) represented by the following formula (3) is not less than 1.5×10(d is the thickness (μm) of the film); and {'br': None, 'i': Nz', 'n', '−n', 'n', '−n, 'sub': x', 'z', 'x', 'y, '=()/()\u2003\u2003(4)'}, '(v) the Nz coefficient represented by the following formula (4) is 1.18 to 2.40{'sub': y', 'z', 'x', 'y', 'z, '(n, ny and nare 3-dimensional birefringences of the film, nis the refractive index of an in-plane slow axis (x axis), nis a refractive index in a direction (y axis) orthogonal to the x axis in the in-plane direction, and nis a refractive index in a thickness direction (z axis) perpendicular to the plane including the x axis and the y axis).'}5. The optical film according to claim 4 , wherein the molar ratio {(A1):(B1)} of the unit (A1) to the unit (B1) of the copolycarbonate is 20:80 to 40:60.8. The optical film according to claim 7 , wherein the molar ratio {(A3):(B1)} of the unit (A3) to the unit (B1) of the copolycarbonate is 30:70 to 60:40.10. The optical film according to claim 1 , wherein the absolute value of the photoelastic constant of the copolymer is not more than 30×10Pa.11. The optical film according to claim 1 , wherein the absolute ...
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