ALEXANDRIA, Va., July 30 -- United States Patent no. 12,372,399, issued on July 29, was assigned to Intellego Technologies AB (Solna, Sweden).

"Multilayer colourimetric indicator" was invented by Claes Lindahl (Solna, Sweden).

According to the abstract* released by the U.S. Patent & Trademark Office: "An apparatus 5 comprises a first layer 20 comprising a colourimetric indicator; and a second layer 30 provided on at least a portion 22 of the first layer 20, at least a portion of the second layer 30 being configured to block and/or absorb a radiation to which the indicator is sensitive or reactive and being configured to be substantially transparent to visible light."

The patent was filed on Sept. 2, 2021, under Application No. 18/043,439...