Optical Variable Devices are widely used for the protection of
brands, products and official documents (passports, id cards, etc.).
One of the most prevalent kind of OVD is rainbow "hologram" for
production of which industrial e-beam lithographs were used. Now
fabrication of OVD dies (prestamps) is possible with ordinary SEM
under NanoMaker control. Special software "RainBow" was recently
developed for OVD structures data preparation. RainBow uses special
feature of NanoMaker for data compact representation and transfer.
RainBow transforms color (bitmap) images into set of diffractive
grids to provide illusion of color image at light reflection. It
allows also to form reflected images with stereo and dynamic effects.
OVD prestamps comprise set of diffractive grids made in resist covered
with thin metal layer.
Photos at the right side (Fig. 2a and 2b) give examples of OVD
prestamps when two images were written on single rainbow "hologram".
The two different images are visible at changing angle of observation