Patent ID: 10067584

Abstract:
A film for writing may include: a rough layer, including a non-flat surface, configured to transmit a first light beam and a second light beam of different wavelength bands; and/or a photonic crystal layer, arranged on the rough layer, configured to transmit the first light beam and configured to reflect the second light beam. A film for writing, which transmits visible rays, may include: a non-flat layer. A difference between a maximum thickness and a minimum thickness of the non-flat layer may be from about 220 nanometers (nm) to about 2 microns (μm). A film for writing may include: a first layer; and/or a second layer on the first layer. The first layer may be configured to transmit first and second light beams of different frequency bands. The second layer may be configured to transmit the first light beam, but to reflect the second light beam.