HOLOGRAM PRODUCTION TECHNOLOGY

HOLOGRAPHIC MASTER PRODUCTION

Either a real object or a computer-generated vector file is needed as a starting point.

For recording, you need an absolutely dark room, several very powerful lasers in red, green and blue (for multicolor holograms due to additive color mixing) and an absolutely vibration-free workplace. The smallest vibrations can destroy a master recording. If the occurring interference waves shift e.g. only by 1/2 wavelength, wave trough and wave crest will cancel each other out in some places. The image would be destroyed. Some of the largest holographic masters for industrial film production were therefore exposed in cave systems underground.

ANALOG EXPOSURE OF A REAL OBJECT AS A HOLOGRAM

The laser beam is split into two beams by a so-called beam splitter and deflected by different lenses and mirrors in such a way that one beam, the "reference beam" hits the holographic film (silver halide) directly and the second beam, the "object beam" hits the object placed in front of the film. The interferences, which are now imaged by the two beams on the holographic film, correspond exactly to the light, which is emitted by the object when we look at it with our eyes. It is therefore a 100% exact copy of the surface of the object.

After the film has been developed, if a light source is used from the same angle as the reference beam, the exact 3-dimensional image of the object can now be seen. Depending on the angle size, the object rotates around its own axis for the viewer and, for example, faces can be viewed from all sides, depending on the size of the shooting angle.

DIGITAL RECORDING OF A COMPUTER GENERATED FILE AS A HOLOGRAM

With the development of the Dot-matrix exposure holography experienced a great leap forward. With this technology, it is possible to expose computer-generated files, be it images, vector graphics, or even short film sequences into a holographic film. In this form of exposure, the silver halide film is exposed point by point by means of a laser, thus transferring the original file onto the holographic film. The standard resolutions here are 24,000 - 120,000dpi.

However, much higher resolutions are possible with special exposure machines. The Nano Optical Imaging Technology allows us to realize resolutions up to 637.000 dpi.

CREATION OF A HOLOGRAPHIC RELIEF STRUCTURE

Holographic relief structures are best suited for industrial duplication. To create these, the transmission master must be copied into a photoresist hologram using a special process. During the subsequent development process, the relief structure required for embossing reproduction is created in the photoresist film according to the partial exposure intensity (interference pattern).

ELECTROFORMING

The relief structure is excellently suited for producing so-called embossing shims (printing plates) from hardened metals via galvanic molding in a special tank. The surfaces of these shims are very resistant and are used to apply the molded relief structure to a desired substrate. Usually a plastic (PET, OPP, BOPP, PVC or coated paper) is used for this purpose. However, with special techniques it is also possible to transfer a hologram directly into other metals (e.g. gold, silver).

HOLOGRAPHIC EMBOSSING SHIMS / RECOMBINING & SEAMLESS PACKAGING FILM

To reproduce holograms in large quantities, embossing shims with different properties are required. Here, the individual motif is recombined in the desired format so that the plastic film, for example, can be optimally utilized in the production process. Register marks and cut marks can also be included in this process.

In the conventional recombining process, the the goal is to obtain a printing plate that can be used in wide-web or narrow-web machines. The printing plates are placed around a cylinder, whereby a so-called "shimline" is created on the side where the plate ends meet, which of course is not a problem with single motifs, but can be disruptive with continuous motifs and can also lead to problems during further processing, e.g. in lamination processes in the packaging sector.

Thanks to a new technique in the manufacturing process of the films, seamless holographic decors (patterns) can be produced, with which it is possible to produce "seamless". These seamless hologram foils can be processed much better and more efficiently in industrial applications.

PRODUCTION OF SECURITY HOLOGRAMS

For the production of security holograms, a plastic film is usually used as a carrier material that can be thermomechanically embossed and has resistant properties to form a sufficiently solid surface that can reproduce the holographic relief structure well.

This film, usually made of coated PET, is rotationally embossed, backed with a special adhesive, applied to siliconized paper, and finally delivered in the desired shape. Since the beginning of 2021, we have also been able to produce paper-based holograms. This enables an environmentally friendly alternative to PET film and offers a similar security effect to breakable vinyl.

The embossing of the hologram, in combination with various Tamper Evident effects in the base material, creates a structure in the label, which not only ensures anti-counterfeiting in the shaping of the relief structure, but also guarantees durability and protection against tampering in the event of removal attempts when applied to the substrate.