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US 7,208,205 B2Granted
Optical film and liquid crystal display using the same
AssigneeKonica Corporation
InventorsToshiaki Shibue, Makoto Honda, Nobuo Kubo, Noriyasu Kuzuhara, Hiroki Umeda, Sota Kawakami, Takatoshi Yajima
Life of this patent
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Abstract
A film for a liquid crystal display comprising a fatty acid cellulose ester film having an acetyl group and a propionyl group is disclosed. Sum of degree of acetyl substitution (DSac) and degree of propionyl substitution (DSpr) of the fatty acid cellulose ester film of the film is 2.8 or less, and a retardation value (Rt value) in the thickness direction define by Formula 1 is 60 to 300 nm.
Claims80
A method for forming a film comprising a fatty acid cellulose ester having an acetyl group and a propionyl group, the method comprising steps of
- casting a dope onto a belt or drum to form a film,
- peeling the film from the belt or drum,
- drying the peeled film by a tenter drying method,
- wherein a sum of degree of acetyl substitution (DSac) and degree of propionyl substitution (DSpr) of the fatty acid cellulose ester of the film is 2.8 or less, and a retardation value (Rt value) of the film in the thickness direction defined by Formula 1 is 60 to 300 nm,
- RT value=((nx+ny)/2−nz)×d Formula 1
- wherein nx represents a refractive index of the fatty acid cellulose ester film in the direction giving maximum refractive index in the plane of the fatty acid cellulose ester film, ny represents a refractive index of the fatty acid cellulose ester film in the direction perpendicular to the direction giving maximum refractive index in the plane of the fatty acid cellulose ester film, nz represents a refractive index of the fatty acid cellulose ester film in the thickness direction, and d (nm) represents the thickness of the fatty acid cellulose ester film.
3 more elements
A film comprising a fatty acid cellulose ester having an acetyl group and a propionyl group,
- wherein a sum of degree of acetyl substitution (DSac) and degree of proprionyl substitution (DSpr) of the fatty acid cellulose ester of the film is 2.8 or less, and a retardation value (Rt value) of the film in the thickness direction defined by Formula 1 is 60 to 300 nm,
- Rt value =( (nx+ny)/2−nz)×d Formula 1
- wherein nx represents a refractive index of the fatty acid cellulose ester film in the direction giving maximum refractive index in the plane of the fatty acid cellulose ester film, ny represents a refractive index of the fatty acid cellulose ester film in the direction perpendicular to the direction giving maximum refractive index in the plane of the fatty acid cellulose ester film, nz represents a refractive index of the fatty acid cellulose ester film in the thickness direction, and d(nm) represent the thickness of the fatty acid cellulose ester film,
- wherein the film is prepared by a method comprising steps of
- casting a dope onto a belt or drum to form a film,
- peeling the film from the belt or drum,
- drying the peeled film by a tenter drying method.
4 more elements
A method for forming a film comprising a fatty acid cellulose ester having an acetyl group and a propionyl group, the method comprising steps of
- casting a dope onto a belt or drum to form a,
- peeling the film from the belt or drum,
- drying the peeled film by a tenter drying method, wherein the fatty acid cellulose ester film comprises a fatty acid cellulose ester having a degree of acetyl substitution DSac of 1.5 to 2.3, and a degree of propionyl substitution DSpr of 0.6 to 1.2, and
- a retardation value (Rt value) of the film in the thickness direction defined by Formula 1 is 60 to 300 nm,
- Rt value={(nx+ny)/2−nz}×d Formula 1
- wherein nx represents a refractive index of the fatty acid cellulose ester film in the direction giving maximum refractive index in the plane of the fatty acid cellulose ester film, ny represents a refractive index of the fatty acid cellulose ester film in the direction perpendicular to the direction giving maximum refractive index in the plane of the fatty acid cellulose ester film, nz represents a refractive index of the fatty acid cellulose ester film in the thickness direction, and d (nm) represent the thickness of the fatty acid cellulose ester film.
3 more elements
A film comprising a fatty acid cellulose ester having an acetyl group and a propionyl group,
- wherein the fatty acid cellulose ester film comprises a fatty acid cellulose ester having a degree of acetyl substitution DSac of 1.5 to 2.3, and a degree of propionyl substitution DSpr of 0.6 to 1.2, and
- a retardation value (Rt value) of the film in the thickness direction defined by Formula 1 is 60 to 300 nm,
- Rt value={(nx+ny)/2−nz}×d Formula 1
- wherein nx represents a refractive index of the fatty acid cellulose ester film in the direction giving maximum refractive index in the plane of the fatty acid cellulose ester film, ny represents a refractive index of the fatty acid cellulose ester film in the direction perpendicular to the direction giving maximum refractive index in the plane of the fatty acid cellulose ester film, nz represents a refractive index of the fatty acid cellulose ester film in the thickness direction, and d (nm) represent the thickness of the fatty acid cellulose ester film,
- wherein the film is prepared by a method comprising steps of
- casting a dope onto a belt or drum to form a film,
- peeling the film from the belt or drum, and
- drying the peeled film by a tenter drying method.
5 more elements
Dependencies are inferred from the claim text.