Re: hidden device finder

[Phil Hobbs]

On 2024-01-25 23:49, RichD wrote:
> On January 24, Clive Arthur wrote:
>>> Would you trust this gadget?
>>> https://omg-solutions.com/multifunctional-detector-rf-signal-mobile-phone-camera-lens-magnet-detector-1-8000mhz-spy991/
>>> I expect it would constantly beep false alarms.
>>
>> The camera lens detector is quite ingenious, though it only works for
>> locally monitored cameras. You look through the hole in the device and
>> slowly scan the room for camera lenses while listening for the
>> uncontrolled guffaws of the camera operator.
>
> I have a naive idea. Consider the first law of optics: "I C U, U C ME"
>
> So you use a flashlight to scan the room. If a lens is peeping at
> you, through an aperture somewhere, can't you peep back?
> What makes it invisible?
>
> --
> Rich
>

A lens with a scatterer at the focus works like a cat's eye. (Which,
not coincidentally, is also a lens with a scatterer at the focus.) Back
in the film camera days, pictures of people taken with direct flash
usually showed 'red eye', due to precisely this effect.

Some years ago, I worked on a patent case (*) at the International Trade
Commission. (The ITC is an administrative law 'court' operating as part
of the Commerce Department. The fancy-schmancy name probably lets them
pay the judges less.) ;)

This one was a real beast.

Back in 1967, during the Vietnam War and soon after the invention of the
laser, some bright spark working for the military came up with this
scheme for killing enemy snipers: you send out a broad collimated laser
beam from a scope, and shoot a .50-caliber round at the places where you
see those bright red-eye glints. With perfect aim, that would send a
bullet right through the poor guy's sniper scope, but anywhere close
would probably be sufficient. So naturally our bright spark filed a
patent on the idea of sending out a collimated laser beam and detecting
the back-reflection.

Of course, the patent was immediately classified, and so nobody knew
about it for over 40 years. Lots and lots of laser applications
developed in which this technique was used, including essentially all
optical disk systems, laser radars, long-distance lidars, and many, many
others.

Then in the mid-teens it got declassified again, and suddenly there was
this patent that covered a good third of all laser applications,
amounting to tens of billions of dollars per year, *and had 20 years to
run.*

I got hired to help defend Samsung against this one. ITC cases are real
rocket dockets, typically taking nine months to a year to reach final
judgment, versus two or three years for a normal district court case. I
did only a part of the work on it, but kept an eye on its progress.

Samsung settled out of the case, but the other defendants soldiered on
and eventually won on a technical legal point: the plaintiffs lacked
'prudential standing', i.e. they hadn't made sure they had clear
ownership of the patent. That was a huge black eye for the plaintiffs,
and especially their lawyers: it looked like they owned the world, and
they wound up with zilch.

Lucky escape for everybody else, of course.

Cheers

Phil Hobbs

(*) Optical Devices LLC v. Lenovo Group et al.
Investigation 337-TA-897, US International Trade Commission, 2014

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

[john larkin]

Classifying a patent is a direct conflict with the concept.

[Phil Hobbs]

On 2024-01-26 18:44, Joe Gwinn wrote:

> But happens all the time, especially when a shooting war is involved,
> and there is nothing the inventor can do to stop it. One would hope
> that the inventor is compensated for this taking, but the government's
> opinion of worth may differ from the inventor's opinion.
>
> Phil: What is the patent number?
>
> Joe Gwinn

The patents were issued to Norman R. Wild and Paul M. Leavy.

RE40,927 RE42,913 RE43,681

Cheers

Phil Hobbs

[Chris Jones]

On 27/01/2024 8:41 am, Phil Hobbs wrote:
> Back in 1967, during the Vietnam War and soon after the invention of the
> laser, some bright spark working for the military came up with this
> scheme for killing enemy snipers: you send out a broad collimated laser
> beam from a scope, and shoot a .50-caliber round at the places where you
> see those bright red-eye glints.  With perfect aim, that would send a
> bullet right through the poor guy's sniper scope, but anywhere close
> would probably be sufficient.  So naturally our bright spark filed a
> patent on the idea of sending out a collimated laser beam and detecting
> the back-reflection.

Sounds like one would want a scope that is not only telescopic but also
periscopic.

[Phil Hobbs]

Chris Jones <lugn...@spam.yahoo.com> wrote:
> On 27/01/2024 8:41 am, Phil Hobbs wrote:
>> Back in 1967, during the Vietnam War and soon after the invention of the
>> laser, some bright spark working for the military came up with this
>> scheme for killing enemy snipers: you send out a broad collimated laser
>> beam from a scope, and shoot a .50-caliber round at the places where you

>> see those bright red-eye glints.ÿ With perfect aim, that would send a

>> bullet right through the poor guy's sniper scope, but anywhere close

>> would probably be sufficient.ÿ So naturally our bright spark filed a

>> patent on the idea of sending out a collimated laser beam and detecting
>> the back-reflection.
>
> Sounds like one would want a scope that is not only telescopic but also
> periscopic.
>

It would be nice to have it a meter off to one side!

Of course parallax is a problem.

Cheers

Phil Hobbs