Method for producing optical orientation film, method for producing retardation film, system for producing optical orientation film, optical orientation film and retardation film

A method for producing a retardation film, comprising the steps of:

• (i) preparing an irradiation target substrate and a long continuous photomask, the irradiation target substrate comprising a first long continuous transparent resin substrate and an orientation layer on one surface of the first long continuous transparent resin substrate, and the long continuous photomask comprising a second long continuous transparent resin substrate and a desired ultraviolet shielding pattern on one surface of the second long continuous transparent resin substrate;
• (ii) feeding the irradiation target substrate continuously;
• (iii) feeding the photomask continuously;
• (iv) producing a laminate by laminating the photomask fed in step (iii) on the orientation layer of the irradiation target substrate fed in step (ii);
• (v) exposing the orientation layer in the pattern by irradiating the orientation layer with first linearly polarized light in a constant polarization direction through the photomask, while feeding the laminate obtained in step (iv) in the longitudinal direction of the laminate;
• (vi) removing the photomask from the laminate irradiated with the linearly polarized light in step (v);
• (vii) forming an optical orientation film in which parts in different orientation directions are disposed in the pattern in the orientation layer on one surface of the first transparent resin substrate by irradiating the orientation layer exposed in the pattern of the optical orientation film obtained in step (vi) from the orientation layer side with second linearly polarized light in a different polarization direction from that of the first linearly polarized light in step (v) ;
• and
• (viii) forming a retardation layer on the orientation layer of the optical orientation film.

A system for producing an optical orientation film, comprising:

• a means of continuously feeding an irradiation target substrate comprising a first long continuous transparent resin substrate and an orientation layer on one surface of the first long continuous transparent resin substrate;
• a means of continuously feeding a long continuous photomask comprising a second long continuous transparent resin substrate and a desired ultraviolet shielding pattern on one surface of the second long continuous transparent resin substrate;
• a means of producing a laminate by laminating the continuously-fed photomask on the orientation layer of the continuously-fed irradiation target substrate;
• a means of exposing the orientation layer in the pattern by irradiating the orientation layer of the laminate from the photomask side with first linearly polarized light in a constant polarization direction;
• and
• a means of removing the photomask from the laminate irradiated with the linearly polarized light.