US 12,455,198 B2
Orientation-independent temperature sensor
Brian S. Huffman, Belle Mead, NJ (US); Deniz Boyu, Dover, NJ (US); and Gene A. Hofer, Lake Zurich, IL (US)
Assigned to ZEBRA TECHNOLOGIES CORPORATION, Lincolnshire, IL (US)
Filed by Temptime Corporation, Morris Plains, NJ (US)
Filed on Aug. 26, 2022, as Appl. No. 17/896,383.
Prior Publication US 2024/0068886 A1, Feb. 29, 2024
Int. Cl. G01K 11/06 (2006.01); A23L 3/00 (2006.01); G01K 1/024 (2021.01); G01K 3/04 (2006.01); H01Q 1/22 (2006.01)
CPC G01K 11/06 (2013.01) [G01K 1/024 (2013.01); H01Q 1/2225 (2013.01)] 25 Claims
OG exemplary drawing
 
1. A temperature exposure indicator comprising:
a substrate;
a first electrode and a second electrode on the substrate, the second electrode spaced apart from the first electrode;
a temperature responsive material disposed between the first electrode and the second electrode, wherein the temperature responsive material comprises an insulating material and conductive particles, the temperature responsive material having an initial electrical property; and
an absorbent coupled to the temperature responsive material,
wherein the insulating material is configured to liquefy in response to exposure to a temperature above a predetermined threshold temperature, and
wherein the absorbent is configured to absorb at least a portion of the liquified insulating material, such that an electrical property of a remaining portion of the temperature responsive material not absorbed by the absorbent is changed from the initial electrical property of the temperature responsive material to a changed electrical property.
 
17. An RFID tag comprising:
an antenna;
an integrated circuit electrically connected to the antenna; and
the temperature exposure indicator of claim 1, wherein the temperature exposure indicator is electrically connected to the antenna and the integrated circuit,
wherein the integrated circuit is configured to detect, the change in electrical property of the temperature exposure indicator and to communicate an indication of the change in electrical property via the antenna.
 
23. A temperature exposure indicator comprising:
a substrate,
a first electrode and a second electrode on the substrate, the second electrode spaced apart from the first electrode;
a temperature responsive structure coupled to the first electrode and the second electrode and having an initial electrical property, comprising:
a first layer including a temperature responsive insulating material, the first layer disposed in a location between the first electrode and the second electrode, and
a second layer including conductive particles, the second layer blocked from contact with at least one of the first electrode and the second electrode by the first layer;
an absorbent coupled to the temperature responsive structure;
wherein the temperature responsive insulating material is configured to liquefy responsive to an exposure to a temperature above a predetermined temperature exposure threshold;
wherein the absorbent is configured to absorb a portion of the liquified temperature responsive insulating material, removing the portion of the temperature responsive insulating material from the location,
wherein, when the temperature responsive insulating material is absorbed by the absorbent, the conductive particles are configured to move into the location, causing a remaining portion of the temperature responsive structure to have a changed electrical property.