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My "magic" mirrors are purely technological and are only able to transmit light. More precisely, they can display the visible and infrared spectrums, and communicate via radio waves. They're basically glossy phone screens without any bezel.

Now, there are obvious uses to these, but there's one unorthodox trick, seen briefly during a fight scene. The heroes are in trouble, as their opponents are overpowered Mary Sues, so they use the "ultimate technique" of the mirror. They hold out their devices towards the enemy and simultaneously show an exploding flashbang, the video feed of which ends up blinding the assailants for five seconds.

To summarize, when in this mode, the mirrors can briefly produce (white) light, strong enough to flash-blind people for five seconds. This doesn't have any detrimental effect on the display, but is rather taxing for the battery and can't be done in rapid succession.

The concept is cool, but I'm struggling to find a display technology (like OLED or LCD), even if only experimental, that would be able to actually do what was defined in the criteria. Do you have any ideas on what display type would fit the bill?

To be clear, magic magic doesn't exist here, it's just another name for technology and science, and they're called mirrors not because they were designed to be those, but because they're very glossy and don't have any anti-glare coating.

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  • $\begingroup$ I'm uncertain about the exact nature of your magic or technology, but I suggest you look at the Archimedes death ray. This was discussed on myth busters and has been proposed to consist of a group of soldiers that carried polished shields and used the reflected sunlight to set ships on fire. Think solar hot dog cooker. with magic involved, why not? $\endgroup$
    – DWKraus
    Apr 3 '20 at 23:13
  • $\begingroup$ Thanks for the edit, much better. I still think it's confusing: so you want reusable flashbangs that can only light up one side so then if they are thrown, they are useless? If you can only bind the people that already see you - you are looking directly at them, awkwardly holding your phone - you've got a horrible weapon. Could you clarify what exactly you want to do? "how bright can we make a display" is a strange question to me for various reasons. I'm not sure I get this. With sufficient technology as bright as you need it, that's exactly what you say yourself in the last paragraph $\endgroup$
    – Raditz_35
    Apr 5 '20 at 10:27
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Ultra-***ing-high dynamic range displays lol. An iPhone 11 Pro Max is around 42 lumens at max brightness, full white screen with the HDR extra 20% white.

An incandescent 100W lightbulb produces around 1600 lumens.

Here is some info on the world's brightest "torch"at 99000 lumens: https://www.elitereaders.com/1000w-homemade-flashlight-worlds-brightest/ You can see how huge it is, the power source and the cooling it needs.

A flash grenade that causes temporary blindness in a radius of about 5m even in daylight hits about 12 million lumens. That is a lot more than anything else portable, you can imagine the kind of power you'd need to produce even a fraction of that that's seen through the screen.

If, however, you just want a flash the duration of a flash bang, but don't want the display to produce that kind of output continuously, that's more doable. External camera flashes have peak output in the hundreds of thousands or even millions of lumens for larger bulbs.

That's the kind of power you'd need to give someone sunspots in daylight for a while. If you only want to use it at night, you'd need a lot less obviously. The brightness of a regular lightbulb will do the trick for a few seconds.

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  • $\begingroup$ I don't claim to understand the op, however there is a significant difference between a mirror and a torch or flash bang. I think this answer is missing some definite conclusions (or answers). This answer is what the op should already have included in their post because they of course did research beforehand ;). What I'm saying: this is a good contribution, but not an answer. Hopefully the op will work this into their post $\endgroup$
    – Raditz_35
    Apr 4 '20 at 10:15
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    $\begingroup$ @Raditz_35 I don't think it's an actual mirror. Look at the question again: "The concept is cool, but I'm struggling to find a display technology (like OLED or LCD), even if only experimental, that would be able to actually do what was defined in the criteria." and "and they're called mirrors not because they were designed to be those, but because they're very glossy and don't have any anti-glare coating." He's looking for a display technology. $\endgroup$
    – Curiosity
    Apr 4 '20 at 21:48
  • $\begingroup$ I've just seen the edit, I guess you are right? However this imo is still research that should've been done by the op beforehand. I don't see a definite answer in your post, party because the question still is a mess $\endgroup$
    – Raditz_35
    Apr 5 '20 at 10:18
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I don't think a "display" can accomplish this... but if it's a feature intentionally built into the mirror (and not just an "accidental" misuse of what it could otherwise do), there are certainly LEDs bright enough for your purpose. Check out what gets used in tactical flashlights, or this video (which is using essentially the same LEDs that you would use in a tac-light, only more of them).

As you've already noticed, they eat power like crazy and generate quite a bit of heat also, but if you're only firing them for a second or so (of actual on time; note that strobing them is probably just as good), you're probably okay.

The trick will be getting enough of this sort of thing that can also shine through your graphical display elements, unless you can mount them some other way. In which case... like Curiosity's answer, you're basically trying to build a display with a fantastical peak brightness and contrast ratio.

(BTW, "HDR", at least for displays, is mostly marketing BS for having a high peak brightness and contrast ratio; measurements that have been around for much, much longer than "HDR".)

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  • $\begingroup$ Disagree about the HDR parenthetical. High contrast and high peak brightness literally means high dynamic range. Dynamic range existed just as long, used in measuring celluloid film and signal quality before digital. So there is nothing strange about displays being HDR, means they can reproduce HDR content. There is a certification standard that defines HDR for displays and everything. There isn't one for "high contrast" or "high peak brightness" $\endgroup$
    – Curiosity
    Apr 4 '20 at 22:11
  • $\begingroup$ High peak brightness has nothing to do with "HDR", except to the extent it can improve contrast ratio. "HDR" display (mind, HDR recording*/content is a whole other beast) just means high contrast ratio and ideally expanded bit depth. *Real HDR would use floating-point for a genuinely expanded range (genuine HDR content does this), but AFAIK "HDR" displays are still 10- or 12-bit fixed point, which has been around longer than stuff has been marketed as "HDR", which is why the marketing annoys me. BTW, HDR display standards do specify minimum contrast ratio and peak brightness. $\endgroup$
    – Matthew
    Apr 5 '20 at 15:50
  • $\begingroup$ Actually, I lie, somewhat. HDR diaplys might be using a non-linear scale for pixel intensity, which would make them at least "somewhat" properly HDR, although 10 bits is still pretty lame. But again, the point is that there is nothing particularly technologically "new" about HDR displays. My gripe is mainly in introducing "HDR" as a new buzzword to talk about display properties (in particular, contrast ratio) which have existed for a much longer time, rather than just continuing to use the existing, perfectly serviceable terminology. $\endgroup$
    – Matthew
    Apr 5 '20 at 15:53
  • $\begingroup$ It's a fair point, but a standard for high contrast didn't really exist before. Now that they have HDR content, people want to play that content, so a standard has appeared for displays that can play HDR content and so they called it HDR. If manufacturers get the certification then of course they will market it. Anyway, this is pretty off-topic lol $\endgroup$
    – Curiosity
    Apr 5 '20 at 16:29
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Is the use of light necessary? Cause sound "sounds" like a better way to go.

The main issue with it flashing blind people is that blind people can't really see, though they can still detect light. Maybe it might be so bright it actually damages their eyes somehow, but other than that, it's not likely to really stun them as far as I know. Instead, your mirrors could Emit focused infrasound towards the target. Infrasound, despite inaudible, can cause interesting effects, resonating with certain tissues and causing discomfort or even stunning targets. See the following link about how it is already used as a military tool (note that it also says how infrasound can actually be used to kill a human, so yeah) :

https://littlefield.co/the-psychoacoustic-effect-of-infrasonic-sonic-and-ultrasonic-frequencies-within-non-lethal-cf05e1fd8673

". . . sound with a frequency of less than 16 Hz is inaudible. It’s called infrasound, and its effect on human beings is not completely understood. We do know, however, that high- intensity infrasound causes headache, fatigue, and anxiety . . . Our internal organs (heart, liver, stomach, kidneys) are attached to the bones by elastic connective tissue, and at low frequencies may be considered simple oscillators. The natural frequencies of most of them are below 12 Hz (which is in the infrasonic range). Thus, the organs may resonate."

That way, your magic mirror could actually be launching a directed, inaudible, and very unpleasant attack, flashing a bright light as a means of signaling its effective area to allies, with people mistakenly thinking the light is what's doing the job. Naturally, this association of a strong sonic weapon added to a bright warning light might consume whatever power source it utilizes fast.

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    $\begingroup$ I'm pretty sure that the OP wasn't trying to rob blind people of their sight during combat. Did you mistake "(flash blind) (people)" for "(flash) (blind people)"? Sonic attacks are a good idea still, even if they take a truckload of power. $\endgroup$
    – Corey
    Feb 17 at 23:28
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To answer the specific question: virtual retinal displays.

VRDs use low-power lasers to project images directly onto your retina. Current VRDs are similar to glasses and use mirrors to aim microwatt lasers through the lens of your eye to strike the right part of the retina. In order to get dark areas you need to be looking at something dark since they can't (yet) do anything about the existing background.

Your Magic Mirror devices could be a black surface with tracking sensors and laser projectors designed to project an image into a user's eyes in the visual location of the device itself, thus achieving a nice dark background for full dynamic range. Of course the laser power would have to be a bit higher and the control a lot better, but those are just implementation details. The surface could be a photovoltaic energy source with a nice glossy black finish to give you that 'mirror' look, but matt black would be preferable.

So now you have a hand-held device specifically designed to shine lasers in people's eyes accurately enough to produce a pretty image at short ranges. All it would take to weaponize this would be to increase the maximum output of the projectors. For normal usage the power would be limited by the internal circuitry but with the right code you could unlock the limiters and project enough power to someone's eye to produce temporary blindness. It might take more than one of the devices to produce enough to overload a person's retina, which nicely fits the scenario in the question.

Unlike a flash, strobe or panel display the laser light will not spread out over distance. Up to the collimation limit of the laser it will be exactly as effective at range as if it were immediately in front of the target's eye. This also means that only the target is affected so friendly and non-involved persons won't even see it happening.

There's some hand-waving involved in this solution but no actual breaking the laws of physics. Targeting a person's eyes at range in a dynamic environment with uncontrolled relative motion of the projector and target is likely to be impossible for any kind of controlled image. It might be possible for the simple usage of putting photons on retinas however.

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It might not need to be super-bright at all, depending on where the fight is taking place. If the fight is taking place in a dark place, the amount of light needed to ruin someone's night-vision could actually be quite low.

I remember one Discworld story ("Night Watch", I think) had Sam Vimes out at night closing his eyes while lighting a cigar so as not to ruin his night-vision. That's just a puny match or lighter. Our current screen technologies are a good deal brighter than that.

Hell, you could just whip out a little torch that runs off a couple of AA batteries and shine it in their face.

Think about going inside from the bright sun to relatively dim artificial light or with curtains open only a crack in the middle of summer. You can hardly see a thing for a minute or so until your eyes adjust to the dim light.

That's what your opponents will be going through after you shine a moderately-bright light at them after being adjusted to the dark. Plenty disorienting-enough for a brief advantage in a fight.

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    $\begingroup$ As a smoker I can confirm that closing one or both eyes while lighting a cigarette (especially during the initial 'flash' period of striking a lighter or match) lets you keep seeing in the dark... as much as you normally can at least :) $\endgroup$
    – Corey
    Feb 17 at 23:24

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