The infrapink ultrascan specs are, along with the magnifying glass, the research counterpart to the gas gun's action purpose. Darkwing Duck doesn't use either former nearly as often as the latter and barely uses the infrapink ultrascan specs at all.
It is never explained where the infrapink ultrascan specs come from, but because they share a design with several other of Darkwing's gadgets, the whole likely comes from the same source. Among them is the gas gun, which is one of SHUSH's inventions created for Darkwing. As such, the infrapink ultrascan specs were presumably also made by the organization. They replace the ultraviolet binoculars Darkwing lost in the Salad Sea.
The infrapink ultrascan specs can extend to improve the resolution over a larger distance. The binoculars also are partially a radar to assist detection of crucial details. What is infrapink about them, or what infrapink even is, is not touched upon.
When the power goes down all over St. Canard, Darkwing uses the infrapink ultrascan specs to scout the city from up Darkwing Tower. Thanks to the binoculars, he finds that Megavolt is at work at the power company. Darkwing is going nuts over a lack of crime and first uses his magnifying glass to detect any sort of crime from way up high in the Thunderquack before realizing the infrapink ultrascan specs are a better tool for this purpose. With them, he finds a candy store that looks like it's just been broken into.
Disney Comics comics
When the power goes down all over St. Canard, Darkwing uses the infrapink ultrascan specs to scout the city from up Darkwing Tower. Thanks to the binoculars, he finds that Megavolt is at work at the power company.