Patent ID: 7588709

Claim:
A solution casting method, comprising steps of: providing a casting device for flowing out a dope from a slit, said casting device including a pair of first slit members forming first walls of said slit and a pair of second slit members forming second walls of said slit, said first walls extending in a lengthwise direction of said slit, said second walls extending in a widthwise direction of said slit, a protrusion length of a protrusion being at most 9 μm upon providing for said second slit member with said protrusion protruding from said first slit member in a flow-out direction of said dope or for said first slit member with said protrusion protruding from said second slit member in said flow-out direction; running a support; flowing out said dope from said slit so as to form a casting film; peeling said casting film from said support; and drying said peeled casting film to a film, wherein a pair of side plates is respectively disposed along respective outer surfaces of said second slit members in said widthwise direction of said slit.