| 摘要 |
This invention relates to holograms employing colour addition techniques, and to methods and apparatus for the fabrication of such holograms. The holograms are particularly useful for security applications. A volume reflection hologram storing at least two images, the hologram comprising: a First stored image configured to replay at a first wavelength; a second stored image configured to replay at a second wavelength different to said first wavelength; wherein said first and second images at least partially overlap when replayed together; and wherein said first and second wavelengths are selected such that where said first and second images overlap they give the appearance of a colour defined by a third wavelength different to both said first and second wavelengths. |
