Multi-spectral holographic security marker, method for its manufacture and holographic security system

A method of making a multi-spectral holographic security marker comprising an image plane volume hologram recorded at one or more first replay frequencies in a light-sensitive film data carrier;

• wherein the film data carrier comprises a polymeric material that is pressure-sensitive so that on compression the final replay frequency or frequencies of the recorded volume hologram is or are shifted away from the respective first replay frequency or frequencies, characterized in that
• the image plane volume hologram recorded in the film data carrier comprises graphical data or a linear code or a matrix code containing security data, and
• different areas of the film data carrier have been compressed to the same or different extents after recordal of the volume hologram therein, with the result that a plurality of different areas of the film data carrier have a plurality of different final replay frequencies for the hologram recorded therein, with the different areas having uniquely defined boundaries which together form a security identification code or pattern which provides further security data,
• the method comprising:
• recording, in the film data carrier, an image plane volume hologram having the one or more first replay frequencies, being a hologram of graphic data or a linear code or a matrix code containing security data;
• preparing a die one or more portions of which have a given thickness and one or more other portions of which have at least one thickness greater then the given thickness, the boundaries of the different thickness portions of the die together forming a security code or pattern;
• and
• pressing the die into the surface of the film data carrier or into a surface covering thereon, the pressure being sufficient to move the final replay frequencies of the portions of the volume hologram recorded directly beneath those portions of the die having the greater thickness or thicknesses to one or more final replay frequencies each different from the corresponding first replay frequency;
• thereby creating in the film data carrier an image plane volume hologram of the linear code or matrix code security data, of which at least one area has the first replay frequency or one of the first replay frequencies, and at least one other area has a final replay frequency differing from the first, with the different areas having boundaries which together form the said security identification code or pattern which provides further security data, wherein
• the die is a holographic master die, with one or more portions of a surface thereof carrying the negative of a surface diffraction grating embodying a surface hologram, so that when the master die is pressed into the surface of the film data carrier or into a surface coating thereon, the pressure is sufficient to create, on the surface or surface coating, a surface hologram which is directly above and in precise alignment with an area or areas of the recorded volume hologram which has the first replay frequency or frequencies.

A method of making a multi-spectral holographic security marker comprising an image plane volume hologram recorded at one or more first replay frequencies in a light-sensitive film data carrier;

• wherein the film data carrier comprises a polymeric material that is pressure-sensitive so that on compression the final replay frequency or frequencies of the recorded volume hologram is or are shifted away from the respective first replay frequency or frequencies, characterized in that
• the image plane volume hologram recorded in the film data carrier comprises graphical data or a linear code or a matrix code containing security data, and
• different areas of the film data carrier have been compressed to the same or different extents after recordal of the volume hologram therein, with the result that a plurality of different areas of the film data carrier have a plurality of different final replay frequencies for the hologram recorded therein, with the different areas having uniquely defined boundaries which together form a security identification code or pattern which provides further security data,
• the method comprising:
• recording, in the film data carrier, an image plane volume hologram having the one or more first replay frequencies, being a hologram of graphic data or a linear code or a matrix code containing security data;
• preparing a die one or more portions of which have a given thickness and one or more other portions of which have at least one thickness greater then the given thickness, the boundaries of the different thickness portions of the die together forming a security code or pattern;
• and
• pressing the die into the surface of the film data carrier or into a surface covering thereon, the pressure being sufficient to move the final replay frequencies of the portions of the volume hologram recorded directly beneath those portions of the die having the greater thickness or thicknesses to one or more final replay frequencies each different from the corresponding first replay frequency;
• thereby creating in the film data carrier an image plane volume hologram of the linear code or matrix code security data, of which at least one area has the first replay frequency or one of the first replay frequencies, and at least one other area has a final replay frequency differing from the first, with the different areas having boundaries which together form the said security identification code or pattern which provides further security data, wherein
• the die is a holographic master die, with one or more portions of a surface thereof carrying the negative of a surface diffraction grating embodying a surface hologram, so that when the master die is pressed into the surface of the film data carrier or into a surface coating thereon, the pressure is sufficient to create, on the surface or surface coating, a surface hologram which is directly above and in precise alignment with an area or areas of the recorded volume hologram which has or which have at least one final replay frequency differing from the corresponding first replay frequency.