Forgery proof optoelectric code card reader
First Claim
1. A forgery-proof optoelectric card system including a reader and code cards comprising invisible light and dark codings forming at least one reading track arranged between two cover plates which are permeable to infrared light, said light codings being permeable to infrared light and said dark codings blocking infrared light, and having at least one reading head comprising a photodiode as a light source and a phototransistor as a light receiver, said reading head being arranged in a card-guiding channel of said reader and positioned to read at least one reading track arranged on the code card to be evaluated, supply and evaluation means connected to said reading head for evaluating the information read thereby, characterized in that superimposed over selected ones of said light codings are filters having infrared attenuation characteristics narrower than and lying within the infrared pass band of said light codings, and a secondary light receiver responsive only to light lying within the attenuation band of said filters.
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Accused Products
Abstract
A forgery-proof optoelectric card system is disclosed which includes a reader and code card comprising invisible light and dark codings forming at least one reading track. At least one reading head is provided which may comprise a photodiode as a ligh source and a phototransistor as a light receiver. The light codings having a first pass band to infrared light. Superimposed over selected ones of said light codings are filters having an attenuation band that is narrower than and lies within the pass band of the light codings. Additionally, a secondary light receiver responsive only to light lying within the attenuation band of the filter is provided.
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Citations
13 Claims
- 1. A forgery-proof optoelectric card system including a reader and code cards comprising invisible light and dark codings forming at least one reading track arranged between two cover plates which are permeable to infrared light, said light codings being permeable to infrared light and said dark codings blocking infrared light, and having at least one reading head comprising a photodiode as a light source and a phototransistor as a light receiver, said reading head being arranged in a card-guiding channel of said reader and positioned to read at least one reading track arranged on the code card to be evaluated, supply and evaluation means connected to said reading head for evaluating the information read thereby, characterized in that superimposed over selected ones of said light codings are filters having infrared attenuation characteristics narrower than and lying within the infrared pass band of said light codings, and a secondary light receiver responsive only to light lying within the attenuation band of said filters.
- 9. A forgery-proof card system including a reader and code cards comprising individual first and second codings, said first coding having a first signal pass band for passing signals lying within said band, said second codings having an attenuation band coinciding with said first pass band, at least one reading head being responsive to signals lying within said first pass band, and positioned on one side of said code card, a signal generator for generating signals lying within said first pass band on the other side of said card, filters superimposed over selected ones of said first codings and having a filter attenuation band that is narrower than and lies within said first pass band, and a secondary receiver positioned on said one side of said card and responsive only to signals lying within the filter attenuation band.
- 12. A card for a forgery-proof system comprising individual first and second areas forming at least one reading track, said first area having a pass band for passing signals lying within said pass band, said second area attenuating signals lying within said first pass band, and filters superimposed over preselected ones of said first areas, said filters having an attenuation band that is narrower than and lies within said first pass band.
Specification