Patent ID: 7885481

Claim:
An authenticity proving optical structure comprising: a plurality of minute optical unit areas, wherein each of the minute optical unit areas has a plurality of minute areas having depths representing multiple-valued phase information including one of a quad coding, an octal coding and a hexadecimal coding, wherein the coding is about a Fourier transformation image obtained through the Fourier transformation of different original images so that each of the plurality of minute areas has a plurality of depths in accordance with one of the quad coding, the octal coding and the hexadecimal coding, wherein the plurality of minute areas include minute protrusions and minute depressions formed on a substrate or a film, and when the minute areas having depths representing multiple-valued phase information about a Fourier transformation image obtained through the Fourier transformation of different original images are irradiated with a coherent light, from a coherent light source, a hologram image is produced having the multiple-valued phase information based on the different original images.