Method for embedding and recovering machine-readable information
First Claim
1. 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.
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Accused Products
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.
110 Citations
12 Claims
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1. 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.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
Specification