Publication

Formation of security paper e.g. banknote with colored marking involves providing photosensitive preparation comprising substance which produces colloidal metal particles under UV irradiation effect on a portion of the document

Patrik Willi Hoffmann
2003
Patents

Abstract

A process for providing a security paper, in particular a banknote, with a coloured marking, comprising providing a photosensitive preparation on a portion of said document and submitting at least selected areas of said portion to a light beam, wherein said preparation is capable of forming a film on said portion and comprises a substance capable of producing colloidal metal particles under the effect of UV irradiation, and said areas are irradiated by means of an UV-light beam.

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Patrik Willi Hoffmann
2003
Patents

Abstract

Official source

Related concepts (18)

Ultraviolet

Ultraviolet (UV) is a form of electromagnetic radiation with wavelength shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs; Cherenkov radiation; and specialized lights; such as mercury-vapor lamps, tanning lamps, and black lights. Although long-wavelength ultraviolet is not considered an ionizing radiation because its photons lack the energy to ionize atoms, it can cause chemical reactions and causes many substances to glow or fluoresce.

Nanoparticle

A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 100 nm in only two directions. At the lowest range, metal particles smaller than 1 nm are usually called atom clusters instead.

Colloidal gold

Colloidal gold is a sol or colloidal suspension of nanoparticles of gold in a fluid, usually water. The colloid is coloured usually either wine red (for spherical particles less than 100 nm) or blue-purple (for larger spherical particles or nanorods). Due to their optical, electronic, and molecular-recognition properties, gold nanoparticles are the subject of substantial research, with many potential or promised applications in a wide variety of areas, including electron microscopy, electronics, nanotechnology, materials science, and biomedicine.

Related publications (1)

Formation of security paper e.g. banknote with colored marking involves providing photosensitive preparation comprising substance which produces colloidal metal particles under UV irradiation effect on a portion of the document

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Improved and new properties of resist materials by doping with nanoparticles and nanocrystals