Optical Stun Ray

It’s been patented; no idea if it actually works.

…newly patented device can render an assailant helpless with a brief flash of high-intensity light. It works by overloading the neural networks connected to the retina, saturating the target’s world in a blinding pool of white light. “It’s the inverse of blindness—the technical term is a loss of contrast sensitivity,” says Todd Eisenberg, the engineer who invented the device. “The typical response is for the person to freeze. Law enforcement can easily walk up and apprehend [the suspect].”

Posted on April 7, 2011 at 6:29 AM57 Comments


transmogrified April 7, 2011 6:49 AM

Wouldn’t the expression “like a deer caught in the headlights” constitute prior art for this “patent”?

Juergen April 7, 2011 6:53 AM

Prior art – Tom Clancy used this technology as a plot device in “Executive orders”

Jay from BKK April 7, 2011 7:03 AM

Doctor, my eyes have seen the years
And the slow parade of fears without crying
Now I want to understand
I have done all that I could
To see the evil and the good without hiding
You must help me if you can

Chris M April 7, 2011 7:04 AM

Old news. The term for them is dazzlers. They aren’t quite as effective as Clancy portrayed them but they are currently in use in Iraq at checkpoints as a non-lethal weapon.

Not Anonymous April 7, 2011 7:05 AM

A flashbang does work — and this thing looks like it works mostly the same, minus the bang. Doesn’t sound like much of an invention though.

BF Skinner April 7, 2011 7:30 AM

@tobias d. robison “most blind people”

are most blind people a population of risk? Prone to perpetrate or act violently?

Obviously I’m not including Matt Murdock here.

Chris April 7, 2011 7:31 AM

I’m pretty sure the lightbulbs in my bathroom constitute “prior art” on this patent, especially when I wake up at 4am with nature incessantly calling.

John B April 7, 2011 7:39 AM

While flashbangs work, a large part of that is the concussion. Not sure if ‘just’ a flash will be able to disable a target anywhere near as well.

Also – reflective surfaces will have interesting secondary effects unless the user is protected somehow, and once it’s been used any 3rd party observers will see the defenses used, and it’s back to the arms race we go.

Clive Robinson April 7, 2011 7:42 AM

There is work going back on “non lethal light weapons” for many many years (over 25years to my knowledge).

There are two basic types that I’m aware of one unpleasant the other down right nasty.

The unplesant one uses an intence light to overload the optical sensors in the eye and use up the visual purple, the result is to leave the person in a blank world.

For those who have been screened for diabetic retinopothy you will be aware of this when the camera flash is used to take the picture of your retina.

A second system is much more unpleasent and can induce fits vomiting and unconciousness.

We are probably all aware of the messages given with films and televison programes “warning the following contains flashing images…”

Well the bad news is we are all prone to being attacked by our optic nerves, if a high intesity light source is shone in the eyes and is modulated by certain wave forms it can cause significant disruption in the brain to induce certain states.

There is also a third trick which is to use just out of ordinary visable light at either the IR or UV ends of the band as this gets into the retina but does not always induce the protection mechanisums of flinching or closing down of the iris etc.

I’m not sure which camp these devices work in, but research done in the UK could cause a pig to vomit and or collapse at well over 50meters (a similar device using two achostic microwave sources could induce unconsciousness and death at well over six times that distance).

For some reason the research funding in the 1980’s for “non leathal weapons” for crowd control etc dried up, and the likes of the UK’s Defence Evaluation and Research Establishment got privatised (it became QinetiQ after a real knock down price sale and made certain people extrodinarily wealthy).

Dave P. April 7, 2011 7:49 AM

This was the plot of Michael Crichton’s movie “Looker” from 1981… Pretty cool “light gun” in the movie!

vwm April 7, 2011 7:59 AM

Sound’s like it might cause permanent eye damage.

Besides: “Recovery time ranges from seconds to 20 minutes” — not very reliable.

And: “typical response is […] to freeze” — Hopefully the subject behaves ‘typically’ and does not instead start to kick / slash / shoot around aimlessly.

Clive Robinson April 7, 2011 8:01 AM

I’ve just looked up the patent (I know Bruce does not like looking at them) and all I can say is there is an awful lot of known prior art.


But simply it’s an over sized flash lamp using an arc light which is highly comutated.

As the UK’s Met Police photographic squad know, you can buy 1 million candle power flash lamps that with just the tiniest of adjustment produce a similar beam of light. They discovered some years ago that on some marches people did not like their photos being taken and the photo squad felt themselves under attack when six or eight of these flash lamps were shone in their faces and digital cameras.

One of the reasons the Met Photo Squad are so hated is that they were set up to make a profit, in that the Met Police have been known to sell the photographs and attendant personal details to various private security concernces, which were then used as “psudo evidence” against the people to try and effect their livelyhood, liberty and assets.

Anonymous Coward April 7, 2011 8:35 AM

Sounds like the movie Looker by Michael Crichton. I hope Terminal Man isn’t on its way too…

Dirk Praet April 7, 2011 8:38 AM

Yet another patent troll, or someone who hasn’t taken the time to look into existing “prior art” or visit a rave party. Although it sounds pretty cool, I for one have always been more of a fan of sound weaponry that can be equally effective and much more amusing. We once figured out how to use sound to make someone soil himself and then subsequently applied it in the recording studio to an irritating guitar player in order to reduce his ego to more workable proportions. With success.

Terry Cloth April 7, 2011 8:55 AM

@Bruce: “no idea if it actually works.”

Reminds me of a favorite Gahan Wilson cartoon. View is a patent examiner’s office, examiner standing next to a window, holding a Flash (ahem) Gordon carbine-ish thing, and as he looks down at the sidewalk, says to the inventor “Death ray, fiddlesticks. It doesn’t even slow them up.”

BF Skinner April 7, 2011 9:23 AM

@Clive “A second system is much more unpleasent and can induce fits vomiting and unconciousness.”

I’ve played that game. It was AWESOME.

Tom M April 7, 2011 10:04 AM

Prior art from 1954: “Rear Window” by Alfred Hitchcock features a scene in which Jimmy Stewart’s character uses powerful flash bulbs (before electronic flash became common) to blind and disorientate an intruder.

paul April 7, 2011 11:18 AM

Also a throwaway (along with the ice bullet) in Afred Bester’s 1952 “The Demolished Man”. Albeit the proposed mechanism of action was bleaching of photoreceptors rather than overloading (yeah, sure) of neural networks.

Richard Steven Hack April 7, 2011 11:29 AM

BK Skinner: Love the “Big Trouble in Little China” reference! One of my favorite flicks of all time set right here in San Francisco.

With reference to the device, lots of people buy high-intensity flashlights for self-defense. Martial artists who specialize in effective street self-defense warn that these things are next to worthless against an experienced street fighter who is likely to attack you by surprise and not give you any chance to pull the thing out.

“The typical response is for the person to freeze. Law enforcement can easily walk up and apprehend [the suspect].”

He expects a street criminal, blind or not, to freeze when he hears the sirens? I think not. Also, assailants tend not to assail when there are cops close enough by to just walk up on them. It’s a stupid remark. There’s no “easy” involved here.

“it’s an over sized flash lamp”

Yeah, I carry that in my back pocket every day…not.

Such devices may have their uses under certain circumstances or possibly could be scaled up for crowd control. But there are very few “non-lethal” defenses that actually work against experienced criminals. Generally, you either need a gun (with training) or a knife (with even more training) or martial arts (with still more training). Failing all that training, pepper spray (with some training) isn’t too bad depending on the device you get.

Also, it’s always better to use any self-defense device by surprise rather than threatening someone with it. The assailant is less likely to have a defense prepared if he doesn’t think you have anything.

mcb April 7, 2011 12:04 PM

@ Richard Steven Hack

“Yeah, I carry that in my back pocket every day…not.”

Maybe we could miniaturize this device so that it fits inside one of those spendy carbon fiber biometric wallets http://www.schneier.com/blog/archives/2011/02/biometric_walle_1.html If a goon opens it without first applying the correct thumb he gets optically stunned for his trouble. Improved models could add a puff of OC spray, a 50kv stun gun charge, and a cellphone/GPS combo that rings up 9-1-1 to report a mugger in need of succor and arrest. “Mugger Mines” anyone?

Richard Schwartz April 7, 2011 12:38 PM

And the next thing you know, possession of 75W halogen bulbs within 10 miles of an airport will be a federal offense.

(I’m usually not this cynical. Must be spending too much time reading comments here.)

Nick P April 7, 2011 12:52 PM

@ Richard Steven Hack & BF Skinner

Big trouble in little china was awesome! I used to love it when I was younger but totally forgot about it. Thanks for the reminder!

Wayne April 7, 2011 12:58 PM

“Besides: “Recovery time ranges from seconds to 20 minutes” — not very reliable.”

Reliable enough. Main purpose is to stun the person, or people, and allow your control forces to move in on thm. Give a group a few seconds of time where you can not defend against them and you are in deep dodo.

Clive Robinson April 7, 2011 12:59 PM

@ Harry,

“Isn’t this called a laser pointer?”

No the patent definatly says “non monochramatic” and gives a broad frequency range of wavelength.

The problem with lasers and peoples eyes is they give comparativly little stun compared to the energy level. Therefor lasers will burn holes in you retina without making you even blink (which is one reason to use them in opthalmic surgery).

Look at the patent link I gave and judge for yourself but I’m calling “flash light” on this device plus enough prior art that would have already expired (should anyone have been daft enough to patent it).

Oh and the patent contains sufficient information about the (supposed) inventor so you can track them down.

Maybe time to track down those named on the patent and invite them to defend the granting of the patent.

Clive Robinson April 7, 2011 1:17 PM

Obviously you can make one of these with the aformentioned 1 million candle power flash lights you could/can buy at many “motor accessory” stores.

The principle it uses is to take an intense light source and focus it into a sufficiently parallel light beam (ie colomnate). They have chosen to do it the cheap cheerfull way with a parabolic reflector.

With a little effort and a trip to your loacal telescope or SLR camera store you could come up with a better colomnator in a handy shoulder mount tube design. Call it a “light rifle”.

The only problem with this is somebody is going to say “Now why stop there?”, and go on to say “Just mount it on top of a rifle so when the perp blinks you have a nice still target you can pull the trigger on!”.

Miramon April 7, 2011 1:34 PM

This has been falsely claimed many times in the past. Certainly a very bright light will have effects on people, but there is no magical stun effect caused by a particular wavelength or flash pattern. People will naturally pause for a moment when unexpectedly blinded, but this is not exactly a novel finding. Blinding people is certainly an effective way to reduce their combat effectiveness, but again, I don’t think that’s exactly news either.

Dirk Praet April 7, 2011 3:41 PM


“Blinding people is certainly an effective way to reduce their combat effectiveness”

That is of course with the exception of Jean-Claude Van Damme (“Bloodsport”).

Clive Robinson April 7, 2011 4:41 PM

@ Dirk Praet,

“That is of course with the exception of…”

That’s in films back in real life…

I used to know a sound engineer many years ago who was totaly blind and had been since birth.

He did all the normal things growing up including kicking a ball around.

Well he got married and had kids who when they got to a certain age kicked a ball around.

If they played during the day the kids would win some of the time, but at night with the garden lights out he used to beat them hands down.

Sometimes what might normaly be thought of as a disadvantage will under different circumstances be an advantage.

Irespective of being able to out kick his kids at football, he could hear things the rest of us could not. And it would show in odd ways, such as knowing that it was going to rain soon even though the sun was still shining.

asd April 7, 2011 4:45 PM

damn i was going build something like. A light source/sound/rf bounce it around 30-40hz to the brain matchs then drop it to 1hz and make them go to sleep

Dr. T April 7, 2011 5:00 PM

We already know that people can be trained to function immediately after a flash-bang grenade blast. Not everyone will be stunned by a light blaster. It may overload retinal nerves, but it does not prevent motor responses. Blasting light into an armed person’s face may ‘trigger’ an unwanted response such as spraying the area with bullets. There are few situations in which such a device would be useful. It would become yet another tool (such as flash-bangs and Tasers) abused by law enforcement folks.

Dirk Praet April 7, 2011 6:09 PM

@ Clive

There are lots of documented examples where lack or loss of one sense over time sharpens the others. To stay with films, see also “Blind Fury” with Rutger Hauer.

JK April 8, 2011 1:35 AM

Defence against flash is also easier than say guns, water cannons, pointed sticks … Sunglasses!

Debianero April 8, 2011 4:35 AM

There are a lot of prior art around this. Many self-defense manuals teach about how to use a lantern to freeze an attacker.

Bill April 8, 2011 8:45 AM

@Clive Robinson

Met Photo Squad
They don’t appear to exist. Do you mean the MET Forward Intelligence Team?

One of the reasons the are so hated
is that they were set up to make a
profit, in that the Met Police have
been known to sell the photographs
and attendant personal details to
various private security concernces,
which were then used as “psudo
evidence” against the people to try
and effect their livelyhood,
liberty and assets.

Seems unlikely, what’s the evidence?

If evidence, was it a rogue insider, or a commercial norm?

OK I shall assume you mean the ‘FIT’.

The ‘FIT’s are likely disliked by many because of their Big Brother overtones, which is disquieting or threatening while exercising ones civil rights, especially of protest.

The FIT’s are certainly despised by a minority because FIT’s have occasionally abused their power to assault and unlawfully detain innocent members of the public, some of which are documented here:


Note – I’m applying skepticism to tease facts from fiction, I am not defending the MET.

Fred P April 8, 2011 9:39 AM

It works well on deer.

Seriously, it isn’t something I’d depend on – it’s far too easy to defend against, and while “The typical response is for the person to freeze.” may be accurate, training in blindfighting isn’t that uncommon.

Honestly, if blinded, while I’d be more vulnerable (particularly at range or after a significant duration), I’d also be more dangerous to someone poorly trained up close – because I’d have fewer choices on how to disable an opponent effectively (i.e. I couldn’t be “nice”), and less indications that they weren’t planning to kill me. While this would give an overwhelming advantage for someone who is well-trained, I’m not clear that it would be useful enough to bother keeping on hand.

Overall, I’d advise pepper spray instead. No it’s not perfect, but it’s harder to countermeasure against (or do you really eat lots of spicy food just on the off chance you’ll be hit some day?), and has more effects than essential blindness.

asd April 9, 2011 5:00 PM

This is slightly off topic, but do dog handlers uses high frequency to anger the dog and make it attack?

jacob April 11, 2011 1:10 PM

Yes, prior art. The reason why cops pull up behind you at night the way they do.
I want one to install on computer monitors. When a user messes up, flash in their eyes. It should cut down on service calls to IT due to PEBKAC…..;)
But what would work in server rooms?

neill April 12, 2011 4:26 AM

what if the attacker with the finger at the trigger of a gun gets ‘shocked’ and contracts his muscles in pain … ?

Peter E Retep April 13, 2011 8:25 PM

re: neill

In a contributory felony state,
he bears the responsibility and guilt
for any injuries, deaths, or losses consequent to it.

Matthew April 15, 2011 12:42 AM

Is this significantly different to the use of bright torches by camp guards in WWII? I read somewhere that their torches were supposed to be bright enough to disorient. No idea if it’s true.

tz April 18, 2011 7:08 PM

Way back when, there was a flashlight like device (I think it was in “the complete spy” published before the 1990s). It contained a flashbulb. A flashbulb contains fine magnesium or something that burns brightly so when even a little electricity goes through, there is a very bright flash similar to a xenon strobe. The one for this device was big and packed densely, but it was basically a stun device.

Taylor April 20, 2011 9:10 AM

I’m sorry, I just have to get it out… Am I the only one here that would kill to have lunch with Clive Robinson? (Or at least non-lethally stun?)

Autolykos April 21, 2011 10:51 AM

@ Clive Robinson: That “just mount it on a gun”-concept is probably the reason that taclights are banned for civilian use here in Germany…

Leave a comment


Allowed HTML <a href="URL"> • <em> <cite> <i> • <strong> <b> • <sub> <sup> • <ul> <ol> <li> • <blockquote> <pre> Markdown Extra syntax via https://michelf.ca/projects/php-markdown/extra/

Sidebar photo of Bruce Schneier by Joe MacInnis.