How to test upper limit on IR thermometer?

And what percentage of the IR pyrometer market used this design?

Sounds like ancient history to me.

What is the current percentage of the IR pyrometer market that uses this design.

In the infancy of the industry... ALL of them. Most copied our design(s).

That included Raytheon, SquareD and all that followed.

Nowadays, it costs more to copy a design than it does to just be a damned good engineer and create your own.

Nobody is milling the tops off of chips any more to look inside in an attempt to make a "reasonable" copy (theft). The time frame turns too quickly.

The resistor bolometer set-up in the early days was as in the picture I posted up in a.b.s.e

I used to make these:

They are (were) for looking at insulator strings and pole mounted transformers from the ground. This allowed power companies to find leaky insulators and replace them, saving power.

SoCal needs to do this instead of shutting off power during Santa Anas.

I have never seen so many overtly leaking electrical tower insulators in my life.

Sounds like yet another guess to me. That is sad. That is how you operate though.

The industry uses what they have. There are plenty of cases where they are still using the instrument they bought 25 years ago.

Not everybody has the childish 'run right out and get the new s*it' mentality, like the cell phone crazed twits these days do.

You're a goddamned retard.

And that has what to do with currently available devices?

Evasion noticed.

The "market" does not mean "old junk people happen to have".

From the many ads for many makes and models of IR pyrometers, it appears the market is quite alive and dominated by lens systems.