Patent ID: 8821674

Claim:
A method for manufacturing an image display device through continuously bonding, to an optical display unit, a piece of an optical film comprising a polarizer, comprising performing a series of continuous steps that comprise: a step of providing a material roll comprising a long sheet of an optical film wound into roll shape, wherein at least one marking is formed at or in a vicinity of at least one defect site of the optical film; a step of feeding the long sheet of the optical film from the material roll; a marking detection step of detecting the presence or absence of the marking by inspection means capable of identifying it; a cutting step of cutting all or part of optical layers of the optical film to form a rectangular optical film piece; and a bonding step of bonding the optical film piece to a substrate of an optical display unit, wherein the material roll has a width corresponding to the length of a long or short side of the optical display unit so that the optical film has a width that is entirely available for forming a product part to be bonded to the optical display unit, in the cutting step, the long sheet of the optical film is transversely cut at predetermined intervals along the longitudinal direction of the optical film to form a rectangular optical film piece of a predetermined size corresponding to a size of the optical display unit, the marking has an optical density of 1.5 or more, and a thickness of a center part of the marking is 1.5 μm or less.