Method for forming optical compensating films, optical compensating films formed thereby, structure of optical compensating films, and polarizing plates

The invention provides a method for forming optical compensating films, comprising (a) providing a suspension containing clay; (b) adding a mono-functional acrylic oligomer of formula (I) in the suspension, wherein n1 is 2-25, R1 is C1-10 alkyl or H; (c) adding a water-soluble polymer in the suspension; (d) adding a bi-functional acrylic oligomer of formula (II) in the suspension, wherein R2 is H or CH3, and n2 is 3-50, R3 and R4 independently are H or CH3; (e) after the step (d), drying the suspension to form a film; (f) exposing the film under the UV light to cure the film,; and (g) stretching the film, wherein the film has only a negative C-plate property before the stretching and has both negative C-plate and positive A-plate properties after the stretching.