Hi guys, sorry for the delay, I've been swamped with major projects.
So yes, there seems to be some major misunderstandings about why the deltaK is special.
First of all, if you dont have a sub 50ms time constant for temperature to indicator, you don't have a scanner, you have a thermometer. All those devices with displays out there have very slow time constants and arent useful for scanning surfaces.
Secondly, numeric displays are useless for scanning. Tones and colors are much better. Cameras use colors because they have a fixed display you stare at. A hand held device should use a tone, that leaves your eyes free to swipe the scanner and locate where its tone is peaking.
These two things are CRITICAL. They are what make the deltaK different and special.
Adding a colored led to indicate temperature would be a gimmick only really. Different surfaces have all kinds of colors and you'd never be able to get precise temperature information from a projected color, especially if its a dark surface. Same goes for LED's you look at directly, the eye is nowhere near as sensitive to color as it is to tone, and you dont want to be watching the scanner as you also move it, that doesnt make sense.