Slit Raster Technology
A method of printing and visualization of images using a slit raster which allows getting an image changing effect depending on the angle of observation. A slit raster (optical analog of a lenticular) is a transparent film on which a pattern is printed. The pattern consists of parallel transparent and non-transparent stripes. A scrambled interlaced image is printed under the slit raster (principle of coding is the same as in lenticular technology).
Depending on the angle of observation only one of stripes of the encoded image are visible through transparent stripes of the pattern. Non-transparent stripes blocked up the other stripe. Images are printed by offset or laser engraving (fig. 1–2).
Fig. 1. Slit raster technology scheme:
1 — initial images А and B divided on a number of stripes which is multiple of a number of lenses; 2 — slit raster; 3 — scrambled interlaced image
Fig. 2. Scheme of image visualization at different angles of observation:
1 — encoded image; 2 — slit raster. Images А and B are visualized alternatively at different angles of observation