US 11,773,282 B2
Systems and methods for printing patterns using near infrared upconverting inks
Jon Kellar, Rapid City, SD (US); P. Stanley May, Rapid City, SD (US); William Cross, Rapid City, SD (US); Jeevan Meruga, Rapid City, SD (US); and Tyler Blumenthal, Rapid City, SD (US)
Assigned to SOUTH DAKOTA BOARD OF REGENTS, Pierre, SD (US)
Filed by South Dakota Board of Regents, Pierre, SD (US)
Filed on Jul. 2, 2019, as Appl. No. 16/460,520.
Application 16/460,520 is a division of application No. 14/213,350, filed on Mar. 14, 2014, granted, now 10,358,569.
Claims priority of provisional application 61/827,392, filed on May 24, 2013.
Claims priority of provisional application 61/800,314, filed on Mar. 15, 2013.
Prior Publication US 2019/0338153 A1, Nov. 7, 2019
Int. Cl. C09D 11/50 (2014.01); B41F 17/00 (2006.01); C09D 11/037 (2014.01); C09D 11/322 (2014.01); B42D 25/382 (2014.01); B41M 3/14 (2006.01)
CPC C09D 11/50 (2013.01) [B41F 17/00 (2013.01); B42D 25/382 (2014.10); C09D 11/037 (2013.01); C09D 11/322 (2013.01); B41M 3/14 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A system for printing patterns onto a substrate comprising:
a. at least two near infrared (NIR)-to-visible upconverting inks comprising a first ink and a second ink, wherein the first ink and second ink comprise nanocrystals that host at least two lanthanide metals, wherein the nanocrystals are capped with an organic ligand, and wherein the ink is formed by mixing the nanocrystals with a polymer in a solvent capable of dissolving the polymer, wherein the first ink comprises a first primary color and the second ink comprises a second primary color; and
b. a printer for printing the first ink and second ink, wherein the printer controls an overlap of the first primary color with the second primary color, wherein the printer prints a first layer comprising at least one of the first ink or the second ink and at least a second layer comprising at least one of the first ink or the second ink, wherein the printer prints the second layer after a solvent of first layer evaporates, wherein the printer comprises an ultrasonic nozzle for atomizing a spray comprising the first ink or second ink, wherein the ultrasonic nozzle receives the first ink or second ink at a print head, wherein the ultrasonic nozzle prints homogenous droplets of the spray onto a substrate as the first layer or second layer;
c. a predetermined pattern, the predetermined pattern having the first primary color and the second primary color and one or more secondary colors comprising a controlled overlap of at least the first primary color and the second primary color, the predetermined pattern corresponding to a specific excitation power density, wherein an exact color of the predetermined pattern is determined by the specific excitation power density and at least a composition of at least each of the first primary color and the second primary color, wherein the controlled overlap of the first primary color and the second primary color by the printer alters the excitation power density, wherein the nanocrystals are spread homogenously through the predetermined pattern during printing;
d. the substrate loaded in the printer for receiving the predetermined pattern;
e. an NIR light source having an excitation power density corresponding to the predetermined pattern of the one or more color compositions for revealing a security pattern from the predetermined pattern deposited on the substrate by the printer;
f. wherein the predetermined pattern and security pattern are generated on the substrate in a single printing step by the printer;
g. wherein the organic ligand comprises carboxylic acid and wherein at least one of the upconverting inks comprises 1 wt % poly(methyl methacrylate) in 90:10 v/v toluene/methyl benzoate mixture.