| Title |
Pilnai spalvas perteikiančių taškinių hologramų apjungtų su skaitmeninėmis hologramomis mikrostruktūrų skaičiavimai ir įrašymas femtosekundinės lazerinės abliacijos būdu / |
| Translation of Title |
Rendering and calculation of combined true color dot - matrix and computer generated holograms and their origination employing femtosecond laser ablation. |
| Authors |
Klinavičius, Tomas |
| Full Text |
|
| Pages |
74 |
| Keywords [eng] |
femtosecond laser ablation ; dot matrix hologram ; computer generated hologram ; color ; diffraction |
| Abstract [eng] |
Diffractive optically variable image devices are optical elements that use diffraction to form a holographic image. These devices are widely used to prevent counterfeiting of documents and goods. A dot-matrix hologram is one of many types of optically variable image devices. Due to its ease of mass fabrication it has become a well-established technology in the anti-counterfeiting holographic label market. The ever increasing ingenuity of counterfeiters requires introduction of novel technologies into security labels, such as computer generated holograms. This type of hologram is a more effective means of anti-counterfeiting, however its production is usually more complicated. The next generation of anti-counterfeiting labels will have to be more complex than dot matrix holograms, yet maintain their ease of mass production. In order to create these labels it is necessary to combine the advantages offered by several different technologies while also compensating their shortcomings. In this work a diffractive optically variable anti-counterfeiting security label that combines dot-matrix hologram technology and computer generated hologram technology was created. In order to achieve higher level of security true color dot-matrix holograms were used in this work alongside of ordinary dot-matrix holograms. Custom software was made to calculate the structure of dot-matrix holograms. Custom software was also created to calculate the structure of computer generated holograms. The part of the label that is comprised of dot-matrix hologram was realized by using direct femtosecond laser interference patterning, while the part comprised of computer generated hologram was produced by direct femtosecond laser writing. Optimal formation conditions of both types of holograms on the surface of a nickel foil were determined. |
| Dissertation Institution |
Kauno technologijos universitetas. |
| Type |
Master thesis |
| Language |
Lithuanian |
| Publication date |
2020 |
