Ralph E Lindberg wrote:

I can't think of a single patent where I work has applied for that was
classified (hint, US Navy R&E). I strongly doubt that anyone would seek
any patent that had classified details.

In industry, one uses patents and trade secrets to protect intelectual
property. Patents have to be written in such a way that someone "skilled in
the art" can duplicate the idea.

I'm not sure of the current state of US patent law, but in general it was
intended that someone would read a patent, build the device and improve it.
The improvement would be a deriviative work or it may be something new.

In either case, the original work, or a derivative work would be the exclusive
property of the owner of the patent for a length of time, now 20 years from
first publication or date of filing (whichever is earlier) in the US, and 21
years in the rest of the world.

Trade secrets are different, they rely on things that have never been revealed.
For example, the formula for WD-40, Coka Cola, or KFC breading. KFC is an
interesting combination, the process was patented, the formula was not.

So you can duplicate KFC chicken at home and now that the patent has run out
in your restaurant in theory, but in practice, you can't because you don't
know for sure what the ingredients and their proportions are in the breading.

There quite simply is no need to seek a patent with classified details. It's
similar to a trade secret, but instead of contracts and ethics protecting it,
the secrecy of it is protected by law.

There is also a law going back to the time of Lincoln administration about
developing things under government contract, patenting them and then dedicating
the patent to the people of the US. There is a big tax advantage, if it
interests you, look up the details.

As far as radios are concerned, one could have patented a transformer
consisting of a toriodal core of powdered iron and other materials (aka ferite)
without revealing the other materials.

If that had been a "secret" invention, then others could duplicate the device
but without the formula for the exact compostition of the core, no one would
get the results you did. That's a two edged sword, they may be better at it. :-)

Note that this is just an example, I really have no idea of who invented the
toroid transformer.

Geoff.


--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM