Spectrally-limited bar-code label and identification card
OwnerJames S. Biancoinventor
Life of this patent
Estimating the term…
Abstract
A label or identification card has a base with a region which absorbs invisible light and a region which reflects invisible light. Both regions absorb visible light over a predetermined spectral range. A filter is disposed on the base. The filter transmits both invisible light and visible light over the said spectral range, while absorbing visible light over the spectral range outside the said range absorbed by the two regions of the base. Accordingly, the unaided human eye cannot perceive the information represented by the array of the regions on the base, while this array can be detected by scanning with invisible light. In one embodiment, the bar code is a return-to-zero double frequency code.
Claims14
An article for storing information in a form substantially concealed from the unaided human eye, comprising:
- a base member forming a surface having at least one first region and at least one second region arrayed thereon in accordance with a predetermined information code, said first region being adapted substantially to absorb and said second region being adapted substantially to reflect invisible radiation in a first predetermined spectral range;
- said first and second regions being further adapted substantially to absorb visible radiation in a second predetermined spectral range;
- and
- means forming a filter disposed on said surface for transmitting radiation in at least said first and second predetermined spectral ranges and for substantially absorbing visible radiation outside said second predetermined spectral range.
Dependencies are inferred from the claim text.