Patent ID: 8976449
Filing Date: 2015-03-10
Classification: B42D,G02B,G03H

Abstract:
1. An identification medium, which reflects circularly polarized light having a first circling direction and circularly polarized light having a second circling direction that is opposite to the first circling direction, the medium comprising: a cholesteric liquid crystal layer that is formed with a hologram of a first pattern and selectively reflects first circularly polarized light having a first circling direction, the cholesteric liquid crystal layer having a first surface in an observing side and a second surface in a side opposite to the observing side; and a circularly polarizing layer arranged at the side of the second surface of the cholesteric liquid crystal layer, the circularly polarizing layer having a first surface at the side of the second surface of the cholesteric liquid crystal layer and having a second surface opposite to the first surface thereof, the circularly polarizing layer selectively transmitting second circularly polarized light to the cholesteric liquid crystal layer when natural light enters from the second surface thereof, the second circularly polarized light having a second circling direction which is opposite to the first circling direction, wherein the circularly polarizing layer is formed by laminating a λ/4 plate and a linearly polarizing filter contacting the λ/4 plate, which are arranged in that order, from the observing side, and the linearly polarizing filter selectively transmits linearly polarized light, and wherein a printed layer printed with a second pattern is arranged at the side of the second surface of the circularly polarizing layer.