Method of enabling data entry using substrate comprising IR-absorbing dye
A method of enabling entry of data into a computer system via a printed substrate. The substrate has a surface containing human-readable information and machine-readable coded data. The coded data is indicative of an identity of the substrate and of a plurality of reference points on the surface. The method includes the steps of: operatively positioning a sensing device relative to the surface and sensing the coded data; generating indicating data using the sensed coded data; and sending the indicating data to a computer system. The coded data comprises an IR-absorbing dye having a nitrogen-substituted phthalocyanine.
1. A substrate for enabling entry of data into a computer system, said substrate having a dye disposed thereon, wherein said dye is of formula (IV) or (V):
wherein:
M is H 2 or a metal group;
n is 1 or 2;
each W is independently selected from the group consisting of: hydrogen, sulfonic acid, sulfonic acid salt and sulfonamide,
and wherein at least one W is a sulfonic acid or sulfonic acid salt.
2. The substrate of claim 1 , wherein M is SnCl 2 , V═O or Ga(OH).
3. The substrate of claim 1 , wherein said dye is disposed in the form of coded data.
4. The substrate of claim 1 , wherein said substrate has a surface containing human-readable information and machine-readable coded data.
5. The substrate of claim 4 , wherein the machine-readable coded data is indicative of an identity of the substrate and of a plurality of reference points on the surface.