Drawing on a plasma display with a laser pointer
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- Опубликовано: 30 май 2022
- An orange plasma display will retain an image caused by incident near-UV light. This is an interesting visual combination of photoelectric, hot carrier injection, plasma, and charge trapping effects.
Correction: The orange display is running at 700Hz, 130V in the video. Also, the laser emits no 365nm light. I measured some as low as 380, but the tail isn't as long as I implied! Thanks Matthew King for pointing this out in the comments.
I realize that I may have conflated the issues of one-resistor-per-pixel and the display's ability to maintain an image throughout row scanning. They are separate problems that are both addressed by designing the panel to work on AC. Each pixel can maintain its state (on or off) by being supplied constantly with a lower "sustaining" voltage, and can be set or cleared by giving it a momentary higher or lower amplitude. The sustaining voltage allows the pixel to be emitting light or not, and its state remains because of its own impedance until updated on the next scan. In color plasma displays, separate electrodes are used for sustaining and addressing pixels, and the discharge may be sustained between coplanar electrodes instead of plane-to-plane, as in this display.
It's also a possibility that the dielectric and MgO layer only exists on one electrode (the metal), and the ITO is bare. I don't know.
On this display, if all rows are electrically connected together, and all columns are connected together, and AC is applied to rows and columns, this effect does not work -- no light is emitted at all! At least some of the electrodes (ie every other column) must be left floating to emit any light, and to show this memory effect. So, driving AC plasma panels requires more waveform tricks that I do not fully understand.
Photo of the TFT LCD with funny attribution: en.wikipedia.org/wiki/File:De...
Applied Science video with rotating, flashing neon light:
• Flashing Light Prize 2...
Prior art patents:
patents.google.com/patent/US7...
patents.google.com/patent/US2...
Physics coffee mug in opening shot: www.atomstoastronauts.com/col...
Refs:
sci-hub.se/doi.org/10...
sci-hub.se/doi.org/10...
sci-hub.se/10.1109/TPS.2003.8...
sci-hub.se/10.1109/TED.2003.8...
www.nature.com/articles/ncomm...
sci-hub.se/10.1016/S0026-2714...
patents.google.com/patent/KR1...
www.slideserve.com/urian/i-st...
patents.google.com/patent/US7...
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I don't think you need to worry about your video output schedule, we, your crowd, appreciate your "quality over quantity" approach...
Several things amaze/surprise me about this video. First, that you are able to come up with topics so consistently novel, fascinating, and non-intuitive that I never would've thought to investigate such things on my own if given about a thousand years to do so. Second, that people are still finding use for images that I uploaded to wikipedia 15 years ago, like that reflection microscope image of a Dell Axim PDA's TFT at 8:40 - this is greatly pleasing to me. Thirdly, that there is 365nm radiation coming out of 405nm laser diodes as you mentioned at 5:20. Can that be right? I've measured the spectrum of these cheap laser diodes before and while they're obviously not as clean and monochromatic as a gas laser, they're still way narrower than an LED and have a FWHM of only a couple nm - I'd like to hear more about this because I know you have a spectrometer too so I guess you've seen it firsthand. And fourthly, that nobody ever even knew about this throughout the entire heyday of the neon plasma display during the 80s and early 90s and no one ever made a product exploiting it! Anyway, you are my fav science youtube channel for many years now and I hope the new videos never end!
Thanks so much for your photo! I might have gotten the attribution wrong, but it was taken verbatim from Wikipedia, and I added a link in the description. People were asking about the "forklift driver" ;) Also, I was indeed playing too fast and loose regarding the 365nm from a 405nm laser. I just measured it, and found some 380nm, but definitely no 365. I updated the description.
So @Muonium you are Not the Gabelstaplerfahrer? Oder doch?
Powerful solid-state UV emitters (or even lasers) weren't really a thing until quite recently, so there was no practical way to make it into a consumer product back then unless you want kids at the arcade to fool around with high-voltage mercury lamps and get eye cancer from the hard UV.
@@RealNovgorod .... do you not?
One time a coworker was trying to explain something about a particular part, and she brought up an image from Wikipedia to show me, and it was a photo I had submitted to Wikipedia lol
When I worked for a large chip manufacturer who makes processors for computers... You know the guys. We just used SiO2 for the ILD, inter-layer dielectric, material which separated the layers of metal lines. So essentially just glass. I don't think it was any special recipe of any kind. I think that it is pretty standard semiconductor tech. We just used silane gas and oxygen at specific temperatures and mixtures to grow SiO2 if my memory serves correctly. Now, the chemistry to keep copper from diffusing into it and the techniques to get nice square bottomed etched lines was extremely sensitive and I don't believe that I can discuss that. Glass is a really easy to manufacture dielectric material with suitable properties. It also etches really easily and predictably with HF. It would seem that manufacturing panels like this would be very similar in process techniques.
All I know is I wanna get to know you and bring my styro, explosions n ire, and Neil friends.
@@derrekvanee4567 We all need to have dreams.
BIG HINT 🤣🤣
During my first night flight while training for the my pilot's licensee, in the school's beater C172 from the 70's, the radio's orange display quit working when we needed to be changing and monitoring Air traffic frequencies. The radio still worked, we just couldn't see what channel we were on or what channel we'd be changing to. Having an unknown electrical issue in the air at night was pretty nerve racking, hoping it is not the beginning of a bigger systematic failure. Even the CFL was unable to troubleshoot the issue.
After a couple rounds of troubleshoooting and restarting the avionics to no avail, I shined my LED head lamp near by and the display lit up! I don't remember if the screen was refreshing properly, but I remember for the remainder of the flight, I'd have to "reignite" the display with the LED light every now and then.
I always wondered what the phenomena was, I always assumed the display was just barley being driven below some some energy state threshold and the LED photons gave it just enough kick to change states. I thought the display was an orange cold cathode, but maybe it was a plasma display as show in this vid.
Very cool video as always!
Wow.
Okay that's a situation where piss would pour down my ankles
If the display was neon, then as it ages, sputtering can lower the gas pressure so that it needs more voltage to ionize (ignite) a spot to get light emission. Shining a light on it adds energy to the neon atoms with the same effect as increasing the supply voltage.
_Barely_ and _barley_ are 2 different things.
The radio was a KX-155 right? Most of those King radios have a little photoresistor under the plastic next to the display which is connected to an automatic dimming circuit. As the display ages and becomes dimmer the dimming becomes non-linear and the display gets very dark /off at higher dimming levels (when the light on the photoresistor is low). By shining light on the display you illuminated the photoresistor and temporarily decreased the dimming level and the display lit up again for a while.
Another reason for making the back electrode from metal (except price) is that metals are generally reflective and send additional light in the direction of the viewer. Anyway, superb video again Ben!
Back in the 80s I worked with people like your colleague (and you). They invented a microwave chamber that heated a cup of coffee (not patented) a discrete-logic version of the Pong game (not patented) a laser-based digital data storage/retrieval device using a photographic plate and LASER (patented), which later became the basis of the CD-ROM. These were fun people, often a bit eccentric, but usually quite humble. The best job I ever had primarily because of the people!
It might work similar to the old Tektronix storage tubes. They use flood guns to flood the whole screen with electrons, but the phosphor does not glow because it's not enough energy to excite the electrons until you get a more intense beam of electrons to "activate" the phosphors by giving them an extra charge so that the energy of the flood gun is enough to get the electrons over that charge state and produce light in that spot.
I was going to say that. I'm not that clear on exactly how those worked, but it immediately occurred to me that this might be related physics.
@@hfuy8005 I'm not sure either, but I think it has to do with energy states of the phosphors. It's as if they have some sort of hysteresis.
Yes! Came here to say that. Glad someone was able to say it before it got lost in comments.
7:26 Brings back memories of my childhood,first multimeter and a mains socket.. Hmmm,my meter has a 20 amp range.. This is a 13amp outlet.. Let's measure the current! Lesson learnt,multimeter fixed and socket replaced.
And trousers washed...
We've all been there.
At the risk of sounding like a dummy, why cant you do this? I would imagine that this essentially causes a short circuit in the outlet because the meter has little resistance, but why cant the outlet handle it? From what I understand, outlets can handle something like 1800 watts, so why would a short circuit hurt it? Wouldn't it just be limited to it's max power as if you were running a power hungry room heater? (Which I know has a lot of resistance). Basically I think my question is... why exactly cant you short circuit a plug, and why would it explode? Finally, why would it hurt your meter as long as you had it in the correct current mode?
@@Polite_Cat The voltage that comes into your house is 240v and the current that comes into your house is effectively infinite. V=IR so if you have an outlet that supplies 120v or 240v and you short it with a resistor of ~0 ohms the outlet will do its best to supply infinite current. Very few things are capable of handling effectively infinite current and they don't include multimeters or wall sockets. In theory the only thing that should happen when you short a socket is the circuit breaker popping but in reality outlets are never terminated properly and they behave more like resistors which is where the magic smoke is stored.
I can imagine a legendary crossover event with How to make Everything, Cody's lab, Nile Red, and Applied Science if HTME ever makes it to the modern era.
Interesting effect. Are you sure you are not just simply ionizing one of the UV lines of the argon or neon? One way to find out is to try it in a regular neon bulb. If you can strike it by shining the laser in-between the electrodes, it’s ionization, if it works inly by shining it on the metal, it’s photoemission. But if it were really photoemission, it would make more sense to me that it comes from the MgO, not from the ITO or metal layer buried under a dielectric. Just don’t see how you can have an electron current nearly high enough to strike a neon plasma coming through a dielectric. Just talking out of my rear-end since I have not researched the subject properly…
I think the purple photons are too feeble aren't they? 405nm is equal to 3eV per photon but argon's first ionization energy is like 15-16eV.
You're on the right track, the real explanation is that F (oxygen ion vacancy) and F+ (oxygen ion vacancy + one electron) defect centers in MgO crystals are located at 3.0 and 2.96 eV above the valence band maximum (VBM), respectively. This means that the 3.1eV 405nm laser light is exciting MgO valence electrons into the F level or maybe even exciting an electron in a F+ level into the conduction band as well and that is main reason for increasing the free carrier density in the device. The reason there is an asymmetry in the dot brightness is because the excitation of carriers in those defect levels are populated and depopulated on one side of the device for each polarization of the AC electric field. So you can imagine you have a box of balls and you raise one side and lower the other. The balls will go back and forth. This is the displacement AC current and you're not having a charge pass through the dielectric. So then the laser power is attenuated when it reaches the bottom layer of MgO because it had to travel through the first layer of MgO. Normally the high voltage AC is enough to excite these defect levels or rip them out of their position, but he is operating it in lower voltage where only the laser gives it enough energy to excite the states. The gas in the middle that becomes plasma is used as the luminescent source with a threshold limit minimum it seems. Like there needs to be enough voltage between the MgO layers to start the plasma going. The dielectric is still too insulative to pass enough charge through it. Most metals have a work function higher than 4eV and wouldn't even get excited at 365nm. The amount of 365nm light is miniscule as well. You should be able to do the same effect with regular AC EL displays with MgO too. It's all about the defect states in MgO, that is where the excited carriers start.
@@ramjetross is this the F for farbzentrum / color centers?
@@Muonium1 F (oxygen ion vacancy) and F+ (oxygen ion vacancy + one electron)
@@ramjetross That is a very convincing and knowledgeable explanation!
Man. You continue to impress me with every video you upload.
He definitely provides a unique treasure of priceless informative video content, unparalleled not just on this platform but on the entire internet. He's long since impressed me to the point where I can't even measure it anymore.
hes like the golden goose of weird science ideas. dude never misses
Funny you mentioned neon bulbs. I noticed the output of a neon bulb can be affected by the amount of ambient light.
I have a power on indicator neon on our boiler that's usually in a dark room, and it has a slight AC flicker to it. When I shine a light on it the flicker stops and its light constantly.
Indeed, I also noticed this on a simple mains power block with neon indicator. The bulb would flicker in the dark and be steady when sunlight hit it. Unfortunately that bulb died a long time ago…
I recall reading that neons for logic applications had a touch of some alpha emitting radioisotope in them for that reason.
Maybe it's just more difficult to perceive the flickering when not in the dark. In the dark you would get the maximum amount of 'dynamic range' and thus easier to notice.
After reading further it seems what OP is referring to is an actual thing.
I've got an old power strip with a neon indicator... sure enough, it flickers with lights off and steady with lights on.
You, Quint, and Grady are 3 of my top fav channels to watch.
hey do you channel names so i can find these ppl
@@joejane9977 practical engineering is Grady's channel and Quint Builds is the other.
@@joejane9977 Would also highly recommend 'Breaking Taps', 'The Thought Emporium', 'Nile Red', 'Action BOX', and 'Codys Lab' (if you aren't already subscribed) for similar content
Glad I listened till the end, your intuitions are genius. The patent surprise is a fun twist. Thanks for another great discovery!
It is a sad twist that just serves to highlight the issue with the patent system.
Protecting investment in research yes, stumbling on something no. And not being able to utilize an idea because someone patented it "just because", and not actually protecting a product they would be producing is just sad. The person who stubs his toe on something first should not be allowed to collect royalties on the dispersal of rocks.
there’s just nothing like the glow of these old plasma displays. miss them. they looked just so cool!
I love seeing your investigation process, the questions you ask going through the tests etc, so interesting! 🙌
I really love these technology videos you do. Thanks!
Thank you for the quality content.
Thank you. I absolutely find your videos entertaining while informational. I appreciate all of the detailed thought you put into your topic.
this is one of the most creative channels ever. well done man. this is so cool. you’ve made and demonstrated some crazy stuff, but this is so rad. i love how humble you are and how you share all this cool stuff constantly.
I sure am glad Ben takes the time to publish his endeavors so we can all enjoy them. Lots of people talk about theory, few make practical implementations.
Anyone with any kind of medical degree watching this instantly recognized the burn-in pattern on that plasma display
All the time I've spent looking at these I don't think I ever realized (some of them) were plasma technology 🤷♂️
No medical degrees needed to recognize it either! Lol
It was only once I saw the burnt-in image that I finally had any idea what a "plasma display" was! (I have no medical qualifications, but I've seen those displays enough to recognise them.)
I don't think I've ever heard that term before, and I wasn't aware that those displays were a different technology to the display types I'm more familiar with. I'd never really thought about what kind of display they were, but I probably would have just assumed them to be some kind of backlit LCD tbh.
@@AndrewGillard Most displays that looks like that are just backlit LCDs. It actually has been that way for quite a while. During the transition period of actual plasma displays and backlit LCDs, there were quite a few displays that do a very good job of looking like plasma displays. To the point you would have to take apart the device to see that it wasn't plasma.
Not quite sure why they put so much effort into hiding the fact that it wasn't plasma.
i remember when plasma screen tv's were a big deal and cost 3000$ and people would freak out about turning them off if you paused something or left the room to get something. idk. those things were impossible to see from more than one narrow angle and basically self exploded after owning them for a year or two. sounds like the perfect type of tv to make lots of money with. guess our new tech must be a lot cheaper idk
thanks for always including the journey of how you got to the final result. it's really enlightening to learn how you look at things, amazing content as always.
Plasma TV sets have a property like this. If you look closely, generally only seen in a dark room, when turning it on, before the set starts making a picture, the screen will show a blotchy approximation of what was last displayed when powered off.
You actually can sort of get away with neon bulbs in parallel. Yes, initially, one will hog all the current, but over time (weeks to months, in my experience) it will degrade until they even out. But then, they won't light up all at once, no, instead, on each half-cycle, a random one will light up (and then a different one and then a different one). If you connect about a dozen of them in parallel, after the initial burn-in, they create a really nice dancing light effect.
Big Clive did make one in a video a few years ago very cool effect
Thanks for comming back! This one was something else man
Learnt so much from this, what a rabbit hole indeed. Thanks for taking the time and effort to upload these videos Ben!
I like your channel not only because you're full of knowledge but also because you're quit humble.
Thank you for posting
This was incredibly fascinating, and your ability to explain it clearly is admirable! You've given me a lot to think about!
i like that small rant at the end about never wanting to stop discovering and researching a topic.
I worked as a biomedical. equipment technician for 18 years and this was one of many devices I worked on. if memory serves me correctly this is from a Propaq Encore patient monitor. I wonder if I ever serviced the one this came out of.
I noticed it was a patient monitor at 11:22, where you can see the burn-in of the most common readouts. It looks like their patients' SpO2 was consistently in the 90s.
@@simon_far 90's is pretty typical unless your having serious lung issues. I have tried holding my breath until im ready to pass out and havent ever dropped below 95%
its pretty typical to be 98 or 99%
Amazing video. I don't quiet understand everything but the comment section is very helpful. Many examples and discussions help. This is by far the best comment section of any channel. I know you mentioned this in a previous video.
Hooray, it is a new Applied Science video! The best, most interesting and in depth science channel on RUclips!
I've never been disappointed by one of your videos, stay curious for the rest of us who can't delve as deeply!
Awesomly enlighting, as always, many thanks!
So happy for a vid from you. It's been a while!
Fascinating. Those plasma displays I have hoarded for 15 years have suddenly become useful.
i cannot express how cool this channel is!
This channel delivers, again. Thanks!
absolutely fascinating ! Ben, thank you for the amazing content and your explanation about the physical/working principles.
These youtube videos are like the tv show Dr. House. But instead of diagnosing a patient, Applied Science learns about a new technology/thing. And instead of Dr. House and a team of doctors, we have Ben Krasnow guiding us through the mystery, discovering new detail, and solving the puzzle.
Thanks for the videos :D
you always bring so fascinating stuffs that makes one wonder!thank you.
This is part of the optogalvonic effect, in which the discharge changes it’s resistance due to incoming light. If you sweep a continuous spectrum of laser light (like from a dye laser), you can measure the resistance change of that gas filling the discharge. I used this as a calibration standard (neon lamp - also argon or other gasses that have emission spectra peaks at important calibration wavelengths), and as you tune / sweep the dye laser (in my case a grazing incidence R6G pulsed dye laser) thru the spectrum, when the due laser matches a peak emission of the gas, the resistance dips… and so you know the dye laser is at that exact frequency / spectrum. I would partially power the discharge lamp, and when the laser wavelength matched a strong emission peak, the lamp would light. There are a few other related phenomena to this, one used for deep space photography, by CCD deep-discharging using deep UV from the sun.
Love your vids, they're always interesting and you never know what part of your brain is going to get lit up but it's always so rewarding. Ty.
This is great, as usual. This is truly the level of nerdiness you cannot get elsewhere.
you want to buy my friend
If this is activated by high energy photons, would it work for detecting radiation gamma sources? If it worked like the old fluoroscope x-ray machines, could you use it as a portable x-ray machine? Since scotch-tape being unrolled produces intense x-rays, could that flash the image of your bones in your finger overlayed on the screen?If this is activated by high energy photons, would it work for detecting radiation gamma sources? If it worked like the old fluoroscope x-ray machines, could you use it as a portable x-ray machine? Since scotch-tape being unrolled produces intense x-rays, could that flash the image of your bones in your finger overlayed on the screen?
Ben it's amazing how consistently you make videos that are just absolutely fascinating. Hilarious that a coworker just happened to have patented the observation. Brilliant stuff, I hope I'll make it to the ranks of your fascinating, brilliant people.
Find all your videos interesting. Your Channel is Probably the best Electronics channel on RUclips, wish there were channels with your high level of detail, quality, and professionalism.
This guy breaks my brain so often.... I can't stop watching
I usually don't catch up with your videos in my watch later before your next video is released. So it's probably coming out soon with a really interesting topic!
Great video! The modern would wasn't built by a few dozen "Eureka!" moments but rather millions of accidental discoveries like this.
You are amazing and I love you. Your channel has changed my life. Thank you.
Absolutely fascinating video as always Ben!
That is indeed one deep rabbit hole. Thank you for sharing!
Super cool! Always like your projects
you have taught all of us so much! thanks ben!
best content on youtube yet again! thank you!
Fascinating stuff there! Man, you reminded me of when I was about 7 and decided plugging a 9v dc motor into a 120v ac outlet would make a great miniature fan. My results were the same as yours, BOOM!
I love how you always come up with every possible angle to anything. After about 2/3 of the video I thought: Mhhh, I have an old plasma TV in my basement I haven't used in some years. Wonder what this will do to it. And sure enough, you went there :) Thanks for yet another super fascinating video!
No other channel on RUclips brings me so much positive emotions as this one.
Awesome work yet again! Thanks for the content.
Definitely one of the best placates over the whole internet.
great episode!! very nice experiment and explanation!! TY!
This is fascinating, oddly enough my first thought on how that worked was the one you mentioned last.
It's cool that a coworker had a patent for this.
Other things of note : The ITO and metal conductors will be at opposite ends of the triboelectric series.
Also: Are you sure the dotted effect is due to the AC cycle and not PWM output from the laser? (I've noticed this when waving laser pointers around especially ones with single cell power supplies which rely on a DC-DC converter to power the diode)
I was wondering if it was possible PWM causing it too.
Pretty sure it's because the F and F+ defect centers in MgO crystals are located at 3.0 and 2.96 eV above the valence band maximum (VBM), respectively. This means that the 3.1eV 405nm laser light is exciting MgO valence electrons into these defect levels and that is what is increasing the amount of electron density in these defect states. The reason there is an asymmetry in the dot brightness is because the excitation of carriers in those defect levels are populated and depopulated on one side of the device for each polarization of the electric field. So imagine you have a box of balls and you raise one side and lower the other. The balls will go back and forth. This is the displacement AC current. So then the laser is attenuated when it reaches the bottom layer of MgO because it had to travel through the first layer of MgO. Normally the high voltage AC is enough to excite these defect levels, but he is operating it in lower voltage. The dielectric is still to insulative to to pass enough charge through it. Most metals have a work function usually higher than 4eV and wouldn't even get excited at 365nm. The amount of 365nm light is miniscule as well. It's all displacement current still. You can do the same process with regular AC EL displays with MgO too. It's all about the defect states in MgO, that is where the excited carriers start.
I'm guessing most of Ben's audience would've had that thought.. I'm sure he tried sweeping the laser over some laser-sensitive phosphor like a CRO screen to discount that..
Unbelievably fascinating and fun!
This is so neat. Thank you!
as interesting and amazing as always, Ben, thanks for another great lesson
Very interesting, I'm glad you made this video
PLATO's 1970's terminals had plasma displays. There's a good technical deep dive on how they worked in "The Friendly Orange Glow"
You have single handedly renewed the plasma display. Maybe one day will will see a scanner or signature panels using this tech. Love your videos
There any readable difference when it's brighter/darker IE voltage/resistance? That difference between acrylic & polycarbonate would be a nice way to detect plastics that's exceptionally hard to do.
You try it on a solar cell? I know they emit light when you drive them in reverse and have the same sort of tech inside them. (more in the IR range though IIRC)
the biggest gem on youtube since forever
Amazing! as always
Really cool, hope you can keep digging!
Wow! Thanks for the awesome video!
what happened at 18:12 is absolutely hilarious 😂 the sheer luck that you work with one of the only people in the world who can say "I actually did that over 10 years ago, see I have proof" is astounding
AS :" I suspected the driver is not totem pole, but open collector type..", this quote define why we all enjoy this channel (who doesn't respect they spirit of the First Nation People (aka. Native American where I'm from)).
Another fact is reading those who had commented, look like thay all have a quantumm computer brewing up at some stage in their garage.
I wish I had had RUclips in my college days for my EE studies but now channels like this is part of my ongoing education. Applied Science is at the top of my list for Enovation and Inspirational.
Thank You Ben for your clever, educational and sometimes humorous videos. Only you would go to the trouble of designing a complex machine to crank out cookies. I hope you still use that system from time to time. LOL
Brilliant demo, still amazed the UV from these lasers and the glass barriers don't diminish the effect. Been using this to trigger a plasma in a bottle lately. If you could read back the written data from the array maybe it could make a cheaper X-ray imaging panel. :-)
Wow, how tiny that eprom was. My old 512kbyte eproms were larger than the whole window! Another great video.
every single time you put out a video its amazing. now well have to wait 2 weeks, and all other youtube science channels will pick it up and make tons of money on it...
Fascinating, captain...
This was very cool. You mentioned the idea of using it for I/O, but I didn't see anything about reading the laser-scanned image out of the display. Is it too basic to cover?
Probably terrible res
If it's possible to read, it would be revolutionary. You could turn any old plasma tv into an incredible artistic device
One way would be to stick a CCD behind the display
The resistance of the pixel changes, so that should definitely be detectable through current measurement
@@albertweber1617 like to know more details about, how to do that. I have plasma TV with me. Wanna convert it as drawing panel.
Very interesting video!
Excellent content as always!
Fascinating!
The off state going dark when the laser hits it reminds me of how glow in the dark stuff gets dark when you shine a laser at it. I wonder if the power being on when shined is caused by the change in conductivity that happens with plasma, whereas the off state going dark is about the electrons being dumped. very cool
This reminds me of those CRTs with high-retention phosphorus that were used as display "memory" in some early terminals. I only saw one in the 1990s and back then we didn't have UV lasers at the ready, but I imagine the phosphorus could be excited the same way and retained by the bias voltage (I think that's how they worked).
I'm so happy that you exist!
Thanks, this is absolutely fascinating!
My guess with the large/small dots is, that a small amount of light can bounce between the ITO and Metal and amplifies the effect of the different workfunctions.
But I would agree with the assumption that the ITO and Metal layers have different absorption coefficients for the UV light.
What great timing - I recently used a UV flashlight on glow-in-the-dark material and found that I could doodle pretty well on it. I've since been thinking about painting a ceiling or feature wall with glow paint and using a computer-controlled UV laser pattern scanner to make a big phosphorescent/fluorescent vector display...
Looks like a neat sketch board.
quite fascinating, thanks for sharing...as always!
wow. applied science never ceases to amaze...
Nixie tubes are sometimes driven with some similar biasing. The -120V is constant, and the +60V is switched on and off, so you're alternating between 120V and 180V across the element. This results in faster ignition of the plasma, and also helps eliminate any afterglow.
Incredibly interesting discovery and explanation
That looks like the display from an old hospital vital signs monitor. (and by old, I mean, it probably finally got upgraded last month... Lol)
SpO2 is Peripheral capillary Oxygen Saturation, or O2 Sat.
Looks like most of the patients it served where in the high 90s where we should be!
Another fun video!
Amazing ! Thanks for all this work :-)
Would it work the same if the power supply had only positive half-waves? Or is a polarity reversal necessary to properly power the display?
I hadn't thought about that - if I can nerd-snipe myself with just pen and paper, being in a garage like yours must only amplify the potential!
Would be a fun oscilloscope project, have been thinking of a few applications, great video, thanks!
Wow this is a amazing!
I have a 48 in. plasma TV that I was getting ready to strip for spare parts. I might try to get it working again and try this!