Method for embedding and recovering machine-readable information
AssigneeXerox Corporation
InventorsTrevor I. Martin, John F. Oliver
Life of this patent
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Abstract
Disclosed is a method of embedding and recovering machine readable information on a substrate which comprises (a) writing data in a predetermined machine readable code format on the substrate with a photochromic marking material having a first state corresponding to a first absorption spectrum and a second state corresponding to a second absorption spectrum; and (b) thereafter effecting a photochromic change in at least some of the photochromic marking material from the first state to the second state.
Claims12
A method of embedding and recovering machine readable information on a substrate which comprises (a) writing data in a predetermined machine readable code format on the substrate with a photochromic marking material having a first state corresponding to a first absorption spectrum and a second state corresponding to a second absorption spectrum;
- and (b) thereafter effecting a photochromic change in at least some of the photochromic marking material from the first state to the second state, wherein a first portion of the photochromic marking material is caused to shift from the first state to the second state and a second portion of the photochromic marking material remains in the first state.
Dependencies are inferred from the claim text.