Light polarizing film, a method of continuously fabricating same, and reflective optical devices using same

摘要

There are provided a light polarizing film of a grid type, usable for light at a wavelength in a range of a visible light region to an infrared region, and a method of continuously fabricating the same. A PET film 12 was fed via rolls 13, and a mixed liquid containing poly (vinyl alcohol), formaldehyde, ZnO whiskers after metal treatment, and water was applied to the surface of the PET film to a predetermined thickness with the use of a T-die 14, subsequently executing coating while applying shearing stress by varying peripheral velocity of an upper roll 16 of biaxial rolls from that of a lower roll 16′ thereof, whereupon the ZnO whiskers were oriented in the longitudinal direction of the film. Thereafter, the film was dried and cured through a constant temperature cell 17 kept at a predetermined temperature, and rolls 18 to be subsequently taken up by a take-up roll 19. The light polarizing film obtained was found very high in polarized light reflection property in an infrared region of a wavelength in a range of 1 to 10 μm, and upon measurement of reflectance for two sheets of the light polarizing films crossed at right angles, infrared light reflectance thereof was found at 99%.