Patent ID: 7410605

Claim:
A solution film-forming method for producing a cellulose acylate film comprising steps of: (a) preparing a cellulose acylate solution; (b) filtering the cellulose acylate solution by a cake layer supported by a filtration support, the cake layer being formed by pre-coating a filter aid to the support, said filtering step removing all particles having a diameter of 0.01 mm or larger; and (c) forming a film from the cellulose acylate solution obtained in step (b); wherein said method further comprises, prior to the filtering step, a step of precoating the filtration support in a thickness of from 0.5 to 10 mm using a precoat liquid in which the filter aid is dispersed, wherein the filter aid has an average particle size in a range of from 1 to 150 μm; wherein: (i) the cellulose acylate film produced by said method is used for a liquid crystal display device; (ii) a number of bright point defects observed under crossed-Nicol having a size of 20 μm or more is 0 defect/5 cm 2 , 10 μm or more is 10 defects/5 cm 2 or less, and 5 μm or more is 10 defects/5 cm 2 or less, said number being an average of five samples of 5 cm 2 in a width direction.