1.

Reports at five - "No limits" - on nanotechnology

TV time well established for scientific news provided information about new directions in nanotechnology research to the wide audience. The important results and interesting applications were highlighted. The descriptions were highly adopted to the corresponding public.

F.30 Professional assessment of the situation

COBISS.SI-ID: 4934170

2.

Some possibilities for preparation of diffractive optically variable security structures and their properties

Relatively simple and easily accessible printing technologies enable well educated professional counterfeiters to make good fakes that are not easily discovered. Therefore better and better protection of various documents, trademarks and valuables against forgery is needed. Optically variable devices are among the most important elements that could protect against forgery. The majority of these security elements consist of a diffraction grating, embossed in a suitable material. Such a diffractive optically variable image device (DOVID) enables clearly identifiable optical features, which are possible to recognize by necked eye in a good illumination. The diffractive elements that have only diffractions of lowest order are practically impossible to be forged using any of modern high-resolution copy or scanning machines. If these elements are prepared as a semitransparent overlayer, the protection of the underneath information is considered to be the highest possible. Microstructure and appearance of metalized and semitransparent commercially available DOVID elements were analysed. The connection between the diffraction period and the colour of diffracted light in the plane of incidence was analysed. A simple diffraction structure of the master original for DOVID was prepared by standard photolithography used in microelectronics, and by scanning lithography. For this purpose a thin layer of UV-active photoresist was illuminated trough a special mask or micro-structured by focused UV laser beam. After dissolving the unexposed pattern, the diffraction grating structure was obtained. It was replicated by electroforming. The structure of diffraction gratings on both originals and replicas were analysed.

F.18 Transfer of new know-how to direct users (seminars, fora, conferences)

COBISS.SI-ID: 25217831

3.

Application of nanotechnology for protection of goods against forgery

The lecture was presented on »Nanotechnology day«. It addresses the anti-counterfeit strategies enabled by nanotechnology. The large economic loss counterfeiting goods continuously increases, largely in cosmetics and toys industry. The producers are responsible for fakes. Packaging has the largest potential in protection against forgery. Nanotechnology enters the area with interference and hologram flake-shaped pigments, nanoparticles and hologram foils. Some details were given on preparation and application of transparent hologram foils.

F.18 Transfer of new know-how to direct users (seminars, fora, conferences)

COBISS.SI-ID: 4934426

4.

Study of structures and materials required to prepare master original for optically variable devices

Possible technological steps needed to prepare semitransparent hologram foils for application in optical security documents ware developed. Fabrication of master original includes two possibilities, laser direct imaging and mask photolithography. The suitability of both technologies and materials applied in them were analysed by the quality of replication and hot embossing.

F.09 Development of a new technological process or technology

COBISS.SI-ID: 4917786

5.

Spectrophotometric identification of optically variable security devices

The possibilities for nondestructive identification of optically variable devices (OVD) applied in security printing were examined applying portable spectrogoniometer. Among OVDs highly prevails diffraction gratings and simple structures deduced by combining them. The limited number of measurement geometries applied in spectrogoniometer may therefore be questionable. We have shown that applying 19 geometries suitable data were obtained to form their fingerprint. The diffraction angles provide the direction of diffraction grooves. Reflectance spectra provide the geometrical parameters of diffraction structure. The plenty of data measured by spectrogoniometer is much more abundant than any kind of visual inspection which makes these methods very interesting to differentiate originals from fakes.