Holographic viewing device, and holographic viewing card incorporating it

Abstract

The invention relates to a holographic viewing device that enable printing or the like to be directly applied to a transmission hologram substrate without recourse to any frame for supporting and reinforcing a transmission hologram, thereby simplifying construction while enhancing aesthetic and decorative attributes, and a holographic viewing card incorporating it. The holographic viewing device enables a given image or message to be viewed near the positions of point light sources upon viewing the point light sources through a hologram, and comprises a transparent substrate 41, a hologram-formation layer 42 and a printing layer 45. The hologram-formation layer 42 may be any one of a phase type diffractive optical element having a relief structure 43 on its surface, a phase type diffractive optical element having a refractive index profile in its layer, and an amplitude type diffractive optical element having a transmittance profile in its layer.

Dependencies are inferred from the claim text.