Patent EA-002470-B1 (EA)
Title: Optical images
Inventor: DUNN PAUL
IPC: G02B27/02
Filed: 1997-11-07
Abstract: 1. An article protected from a counterfeit comprising a substrate which is arranged to provide an optically variable image to a viewer, serving for the identification of said article to protect it from a counterfeit, said image being composed of a plurality of pixels, the substrate having a front surface which is formed with a plurality of groups of elemental areas, with different said groups of elemental areas corresponding to respective pixels of said image, and the different elemental areas of each group being formed with respective grooves or ridges or with respective sets of grooves or ridges, the grooves or ridges of different elemental areas of each group being at different orientations within the plane of said substrate so that, at different orientations of the substrate within said plane, different elemental areas of each said group of elemental areas contribute to the respective pixel of the image seen by the viewer, with said grooves or ridges being arranged to direct light to the viewer at predetermined angles relative to the plane of said substrate, by reflecting light incident on said front surface, without interference occurring between light rays directed to the viewer from the substrate so that at different orientations of the substrate in space a corresponding image pixel observed by the viewer is formed by different elemental areas of each group. 2. A substrate as claimed in claim 1, in which at least some of said elemental areas comprise a plurality of said grooves or ridges which are parallel or substantially parallel to each other. 3. A substrate as claimed in claim 1 or 2, in which the grooves or ridges of at least some said elemental areas are rectilinear. 4. A substrate as claimed in any of the preceding claims, in which the grooves or ridges of at least some said elemental areas are curved. 5. A substrate as claimed in any of the preceding claims, in which at least some of said elemental areas are square in shape. 6. A substrate as claimed in any of the preceding claims, in which at least some of said elemental areas are circular in shape. 7. A substrate as claimed in any of the preceding claims, in which, in at least some said groups, the elemental areas are arranged in a linear disposition. 8. A substrate as claimed in any of the preceding claims, in which, in at least some of said groups of elemental areas, said elemental areas are closely packed together. 9. A substrate as claimed in any of the preceding claims, in which at least some of the elemental areas of at least some of said groups comprise two grooves or ridges, or two series of grooves or ridges, forming a stereo pair, the two grooves or ridges, or two series of grooves or ridges, being inclined to each other so as to direct light to the respective eyes of the viewer when the viewer views the substrate from a predetermined angle of view. 10. An article protected from a counterfeit comprising a substrate which is arranged to provide an optically variable image to a viewer, serving for the identification of said article to protect it from a counterfeit, said image being composed of a plurality of pixels, the substrate being formed of transparent material and having a front surface which is formed with a plurality of groups of elemental areas, with different said groups of elemental areas corresponding to respective pixels of said image, and the different elemental areas of each group being formed with respective grooves or ridges or with respective sets of grooves or ridges, the grooves or ridges of different elemental areas of each group being at different orientations within the plane of said substrate so that, at different orientations of the substrate within said plane, different elemental areas of each said group of elemental areas contribute to the respective pixel of the image seen by the viewer, with said grooves or ridges being arranged to direct light to the viewer at predetermined angles relative to the plane of said substrate, by reflecting light incident on said front surface, without interference occurring between light rays directed to the viewer from the substrate so that at different orientations of the substrate in space a corresponding image pixel observed by the viewer is formed by different elemental areas of each group. 11. A substrate as claimed in claim 10, in which at least some of said elemental areas comprise a plurality of said grooves or ridges which are parallel or substantially parallel to each other. 12. A substrate as claimed in any of claims 10 or 11, in which the grooves or ridges of at least some said elemental areas are rectilinear. 13. A substrate as claimed in any of claims 10 to 12, in which the grooves or ridges of at least some said elemental areas are curved. 14. A substrate as claimed in any of claims 10 to 13, in which at least some of said elemental areas are square in shape. 15. A substrate as claimed in any of claims 10 to 14, in which at least some of said elemental areas are circular in shape. 16. A substrate as claimed in any of claims 10 to 15, in which, in at least some said groups, the elemental areas are arranged in a linear disposition. 17. A substrate as claimed in any of claims 10 to 16, in which, in at least some of said groups of elemental areas, said elemental areas are closely packed together. 18. A substrate as claimed in any of claims 10 to 17, in which at least some of the elemental areas of at least some of said groups comprise two grooves or ridges, or two series of grooves or ridges, forming a stereo pair, the two grooves or ridges, or two series of grooves or ridges, being inclined to each other so as to direct light to the respective eyes of the viewer when the viewer views the substrate from a predetermined angle of view.