Layered film fabrication method, layered film defect detection method, layered film defect detection device, layered film, and image display device

A defect detection method of a layered film in which at least a polarizing plate and an optical compensation layer are layered;

• the method comprising the steps of:
• irradiating a light on the layered film from a light source arranged on the polarizing plate layered side of the layered film;
• imaging a transmitted light image of the layered film by an imaging unit arranged on the optical compensation layer side of the layered film;
• and
• detecting a defect existing in the layered film based on the transmitted light image imaged by the imaging unit;
• wherein
• the imaging by the imaging unit is performed via an inspection polarization filter arranged adjacent to the imaging unit on a light path between the light source and the imaging unit, and an inspection retardation filter arranged between the inspection polarization filter and the layered film on the light path between the light source and the imaging unit.

A defect detection device of a layered film in which at least a polarizing plate and an optical compensation layer are layered;

• the device comprising:
• a light source arranged on the polarizing plate layered side of the layered film and irradiating a light on the layered film;
• an imaging unit arranged on the optical compensation layer side of the layered film and imaging a transmitted light image of the layered film;
• a defect detection unit for detecting a defect existing in the layered film based on the transmitted light image imaged by the imaging unit;
• an inspection polarization filter arranged adjacent to the imaging unit on a light path between the light source and the imaging unit;
• and
• an inspection retardation filter arranged between the inspection polarization filter and the layered film on the light path between the light source and the imaging unit.