microprint   2

Anti-Counterfeit Measures for Currency - DataGenetics
A modern bank-note is an incredibly sophisticated device. Special kinds of paper (and sometimes plastic) are used to manufacture bank notes, as are special inks.

Some of these inks change colors depending the angle you look at them. Some inks can be made sensitive to heat and change color. Some inks are thick and their presence can be detected under fingers and thumbs. The ink can be magnetic to allow detection by machine, or be sensitive to non-visible light, or made to fluoresce under UV.

‘Water-marks’ can be embedded into the paper during manufacture, and/or threads, fibers, metals strips, stripes or other contrasting substances weaved inside. The printed designs are made very intricate, requiring high resolution printers to duplicate, and the spacing of lines in the engraved patterns are cleverly spaced so that if they are scanned at lower resolution, then moiré patterns will appear in the designs. Multicolored inks with subtle transitions can be employed and even foil and holograms included. Of course, all bank notes have unique serial numbers too.

Bank notes can be peppered with patterns of micro-perforations drilled by lasers, or be imprinted or embossed to raise letters. A good list of current techniques used to protect bank notes can be found here.

However one of the most interesting counterfeit prevention devices, and the topic of this post, is a construct known colloquially as the “Eurion constellation“. It’s a special pattern of dots that is baked into design of bank notes to allow scanning devices to identify the image of being a bank note (see right).

You might not have noticed them, or been aware they are they, but they are hidden in plain sight. It’s one of those things that, once you’ve seen, you can never unsee.
cash  bills  counterfeit  fake  printer  Eurion  patterns  signature  tag  watermark  copier  scanner  digital  imaging  microprint  moire 
6 weeks ago by Tonti
Semprius, Inc. :: Semprius is developing low cost, high performance concentrator photovoltaic (CPV) modules to make solar power generation economically viable in sunny, dry climates.
Interesting use of extremely small solar cells with concentrating optics. They claim they can run without heat fins for thermal management, but I have my doubts. Also claiming wide acceptance angles, but which might be true due to the optical geometry of the concentrators. The microprint transfer system allows wafer reuse, which is interesting...
CPV  concentrating  solar  PV  power  generator  green  energy  materials  science  research  technology  multilayer  gallium  arsenide  GaAs  multijunction  cell  microcell  wafer  substrate  reusable  manufacturing  microprint  transfer  Delicious 
december 2011 by asteroza

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arsenide  bills  cash  cell  concentrating  copier  counterfeit  cpv  delicious  digital  energy  eurion  fake  gaas  gallium  generator  green  imaging  manufacturing  materials  microcell  moire  multijunction  multilayer  patterns  power  printer  pv  research  reusable  scanner  science  signature  solar  substrate  tag  technology  transfer  wafer  watermark 

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