The Microspheres Hiding in your Phone's Screen

[@BreakingTaps]

I forgot to mention: application is done with a hot bar and mild pressure. My tape for example (AC-7106U) needs 180C and 2MPa pressure for 10-15 seconds. Strange Parts shows how it's applied to an FPC about two minutes into this video if you want to see it in action: kzbin.info/www/bejne/oaSQnYZnZrl8l7s The adhesive ends up being closer to a permanent heat-set epoxy than a removable tape adhesive. I'm trying to debond the microchip right now to take a closer look, but it's proving very tenacious!

[@fjs1111]

Good work!! I forget what it's called but the old LCD displays used a flexible rubber "Z" strip with thin metal sheets with flexible rubber. Worked really well!

[@flubba86]

Thanks for that additional info. That was the biggest question I had after watching this. Trying to work out how hard they need to push the component down on the tape to crush the balls, and how it doesn't just spring back off, In other words, what keeps the pieces clamped together? Also the example where the traces were contacting the pads without the aide of the balls, I was trying to work out how that happens when there should be some thickness of tape between them. Heating it must liquefy the carrier compound to an extent that it pushes out of the way, and cooling it would set everything and hold it in place.

[@donaldharlan3981]

good craft

[@zyeborm]

@@fjs1111 zebra strip and it failed pretty regularly lol

[@imajeenyus42]

The element detection feature is so cool to see!

[@JMMC1005]

It's mind-blowing that this works as well as it does. It sounds like one of those concepts which works in theory, but would be wildly unreliable in practice.

[@Gobhoblin126]

The old school larger scale version of this is called "zebra strips", used for connecting lcds to rigid PCBs.

[@zyeborm]

Fixed many a Nokia and I think Gameboy? With a bit of paper to apply a bit more pressure to those zebra tapes back in the day. I didn't even know this new one existed, that's pretty cool.

[@rbyt2010]

Yup. Used those in the ‘70’s

[@airborne0x0]

Long ago I used the Tattletale 8 SBC which used the similar 'Squishy Bus' to mate to a carrier board. It was always a little concerning due to board flex but it seemed to do the job ok.

[@BreakingTaps]

Gonna see if I can find some in my pile of old electronics! Thanks for the tip, I hadn't see that before!

[@BRUXXUS]

Aye! That's what I've known it by. Still being fairly new to circuitry and building electronics, I only learned of it a few years ago. Real neat!

[@cfdnoob2807]

I learn so much from your videos, as a practicing engineer I always go "Oh, that's how it works."

[@nilstrobaggia735]

IM gay

[@adamPhoebe]

​@@nilstrobaggia735👍

[@jessealexanderbunch9599]

Comments like yours help me know when I found a good channel 😃

[@MadScientist267]

🤦‍♂️

[@rpals5412]

I spend countless of hours asking my dad how stuff works as a kid. I never stopped wondering and I will never get tired of understanding how more things work. Your videos are on a higher level of what I could learn in physics from school and better than "how its made" and "whats inside". it's really high level stuff. I appreciate your work 100% - I hope you will keep making these videos

[@speedypimpin]

Try finding out how they make acupuncture needles and the micro needle they inject cells with

[@matze1508]

holy! This visualization with the gel and the bearing balls was so simple yet amazing. Really enjoying your videos!

[@1000percent1000]

absolutely blown away by the video quality in this one. can only imagine how beautiful these shots are in 4k because 2k is already stunning. great work

[@MrSlackrick]

I'm an EE and I've used ACF hot-bar bonding many times, but I've never seen images like these - great stuff.

[@SahilP2648]

Which companies do EEs get jobs easily at? I am a software developer but I have always been interested in electronics. I wanted to setup a home automation company when I was young lol but the country I am from, it's more likely to not happen. In my country there's no job security for EEs you see. If there was, I probably would be in that field.

[@OMNI_INFINITY]

*Now the question is HOW to use that kind of adhesive for SMT? Hotplate SMT soldering has solder bridging issues and so on, as I sadly found out when trying multiple times. So adhesive of that type seems like a possible solution. Heard if there is already a way to spray a layer of that on a PCB?*

[@LinusTechTipsTemporary]

That sponser integration was smooth like a silka.

[@MarioGoatse]

Man I’m so happy that I randomly clicked on this video. I absolutely LOVE being educated about super cool things that I’ve never thought of before, and then walking away understanding how they work, and why they were designed that way. What an incredible video. Thank you! You earned my like and subscribe fair and square!

[@jboomhauer]

The demo you did alone was worth watching this video for. It explained everything perfectly. Crushed it dude.

[@Golden_SnowFlake]

Really enjoy the fact that you are so clear and concise with your words, that I was able to watch your video at 4x speed and understand 99% of what you said. Well done. Most folks only get 3x.

[@monhi64]

My guy what’re you even training for that has you watching casual KZbin videos on 4x speed. I just tried 2x which is the max and it was understandable just annoying as hell. Like genuine question what possible reason could you have to watch this that quickly, it’s not like you’re studying for a test

[@FrostCraftedMC]

everytime you post, whether its the main topic or not, i learn something i previous thought impossible has already been solved

[@a.r.h9919]

Nothing is really impossible for everything a human can imagine or conceptualise has it's bases on what we have observed or known It's just finding a way of materialising

[@Splarkszter]

@@a.r.h9919 Yup, another way of seeing it is: Nothing is impossible but most things are economically unfeasable.

[@carlameaders4352]

I am not technical at all. Your video was very educational and was so good that even a technically inept person like me kinda understood what you were saying. I’m still mystified that our electronics have progressed so quickly to this. It’s a great time to be alive on the most part. Thank you for the time you put into this.

[@sanveersookdawe]

I think it would be very interesting to see how the microspheres themselves are made and placed

[@VoidHalo]

If you have a green (best color for visibility) laser pointer, you can reflect it off if the surface of a TV or other screen and see the individual pixels in the reflection. You can also do this with a CD or DVD to see the track made of pits and lands. I've been fascinated with this effect of using laser light to view microscopic structures as a reflection. With no lenses. I'm wondering if this method is used in actual scientific applications to visualize microscopic structures. I always find my best ideas have already been thought of, so I expect that somebody would have discovered and exploited this in the last 50nor so years.

[@KaitouKaiju]

Laser microscopes are a thing

[@pontiacg445]

Have you seen how holograms are made? Also, obligatory cheap green lasers can punch your eye out with invisible and undetectable 808nm and 1064nm infrared light. Any DPSS laser like the common 532nm is packing a pump diode that puts out much more than the "safe" 5mW legal limit. Some have IR filters, most cheapos don't. Most any other diode laser, including the new green ones (~500-520nm) is probably grossly underrated on output power due to marketplace regulations. Before those regs, they used to sell them as toys to light stuff on fire. Now they have to be below the legal limit to sell but of course nobody setting these rules ever checks anything. Be careful with those reflections!

[@arabidllama]

I love the physical model you made. It shows the principle working so well! If enough conductive microspheres did manage to bridge two adjacent traces, would the magnetic flux of the sudden current flow cause them to separate? It feels like the sort of system that would tend towards un-shorting itself, which is cool

[@xTheUnderscorex]

They probably still wouldn't meaningfully conduct, since there isn't any compression giving them proper contact with each other. I'm mostly surprised that there aren't too many issues with some unlucky contacts not having any spheres.

[@gsuberland]

I suspect one of the reasons they used electroless nickel phosphorous plating on the pins, aside from corrosion resistance, is that it promotes surface uniformity and reduces surface porosity. Ensuring that there are no surface voids or pits is likely a fairly major reliability factor for applying the tape. Since bare metal is fairly porous, there's a tendency for hydrogen absorption (and adsorption), which might lead to bubbling and delamination of the tape as a result of degassing. A medium-phosphorous EN plating is a pretty simple and relatively cheap way to solve all of those problems simultaneously, and the tooling for it is pretty ubiquitous given that we do it all the time on ENIG / ENEPIG surface finished PCBs.

[@oohshiny8713]

First learnt about Z-tape in Applied Science's video about building the replica DSKY display, where the adhesive ended up pulling the electroluminescent phosphor/dielectric/ink stack-up off the glass. Very cool to see a deep dive on how it works!

[@BreakingTaps]

Oh neat, I didnt remember that he used ACF for that project! Will have to go give it a re-watch

[@melody3741]

Me too!!!

[@ryebis]

Thanks! great video

[@RooMan93]

Speaking of LCDs, Ive heard they use tiny glass balls to separate the layers of glass. A cross section would be cool to see. Perhaps if you're careful enough we could see what happens when the layers are to close or to far apart.

[@billwhoever2830]

Seeing the metal levels and the vias between them was fascinating! It really shows the thickness difference between the silicon piece and the metal layerers that were deposited on it.

[@JoseSilveira-newhandleforYT]

Excellent explanation and demonstration! Quite impressive how you prepared all this for a general audience!

[@bradprimeaux8443]

I read the title and immediately thought: "They must be using some fancy crystal structure that's conductive in one direction". But instead I got tape and conductive balls. Love it. You never fail to amaze me.

[@BreakingTaps]

Honestly that was my assumption too! I figured it had some kind of pillar structure :)

[@bradprimeaux8443]

@@BreakingTaps Crazy how simple some solutions to complete problems can be.

[@JohnDuthie]

Thanks! I never understood how complicated it was to create continuity between microscopic pads. I guess I just assumed it was the same as regular solder.

[@BreakingTaps]

Thank you!

[@nonameworks]

I've never seen a guy so dedicated to reading his comments. Almost every comment I see is liked by this guy or even commented on. Loving these videos so far, the explanations are easy to understand but still don't simplify it too much. Best informational channel I've seen yet.

[@shortlessonshardquestions8105]

Wow! That is a much "messier" process of establishing a conductive pathway than I would have thought. Very cool and extremely well demonstrated and explained. Thank you!

[@randomname4726]

Wow, that was really impressive to see. You post some of the best videos out there, I'd happily watch longer form content.

[@ddegn]

Agreed. This video was over way too soon.

[@fep_ptcp883]

Man, this solution is genius. And the way you showed it to us and explained is even better! You've just earned a new subscriber. Best regards from Brazil

[@BPSspace]

I have yet to watch a video of your's where I don't learn something new. Keep up the great work dude, had no idea about this tape!

[@BreakingTaps]

🥰

[@Ailtir]

The probability of the spheres forming chains reminds me very strongly of concepts like percolation and clustering in random graphs.

[@LongnoseRob]

Great work! Have you tried to measure the resistance of such connections?

[@BreakingTaps]

I was going to... and totally forgot 😅 The spec sheet for mine claimes 1ohm resistance so it's just "ok". Also limited to

[@LanceThumping]

@@BreakingTaps Is that all it says or does it give it as a per area? I'd expect larger or smaller pads would affect the resistance and current capacity.

[@BreakingTaps]

@@LanceThumping Datasheet just says "ITO electrodes all over / TCP; bonding width, 1.5mm", so not entirely clear to me what the actual dimensions were. 😔 Spec sheet is here if you'd like to take a look! www.fsrkj.com/upfiles/201712/22/af0aa1f1cb2886b6f.pdf

[@explosivedude8295]

0:10 You're wrong man. I am watching this on my 50mm film projector.

[@BreakingTaps]

I'm not even mad 😂

[@DigitalJedi]

You're correct about the corrosion resistance for that nickel coating on the pads. We do the same thing for the copper IHS on CPUs. The nickel doesn't corrode away nearly as badly as copper will when just exposed to the atmosphere, let alone any moisture. You wouldn't want to have your traces going green on you, or the surface of your CPU becoming pitted over time.

[@peoplez129]

Chips won't go pitted, because there's generally a layer between them and the IHS, such as thermal paste or pads. So even copper in contact with an IHS doesn't really corrode in its usable life, because it's protected from air at the contact point. Of course everything else would corrode, and that's mainly for aesthetics rather than functionality.

[@DigitalJedi]

@@peoplez129 It's not the inside we're concerned with. That is sealed from the outside world. The silicon itself won't corrode, since it already has a layer of oxide on it. The greater concern is the outer surface, which is exposed to the atmosphere for extended periods of time. Pitting takes a long time and is the extreme example, but even tiny copper oxide spots ruin the thermal properties of that area of the IHS and create hotspots.

[@PabloBatistaArq]

I like how you make your videos so interesting, like you're telling a story

[@BreakingTaps]

Thanks! Really appreciate that!

[@iTeerRex]

Very cool👍. It’s un-freaking-real how much science, engineering, math, manufacturing, ingenuity, creativity… has gone into making every bit of a phone. I’m sure I know only a tiny fraction of it, and still it’s unreal.

[@trollmcclure1884]

right? I've heard that they use psychedelics to reach this level of visualization and creativity 🙂

[@intersections2428]

these advances are beyond reason, the tech is almost other worldly

[@muttlee9195]

Alien tech

[@BuzzingGoober]

There's nothing complicated about connecting two conductive surfaces with a metal ball. They envisioned how they could make it happen, and this was how it was made to happen. You just 'aren't that guy' if you cannot come up with solutions like this.

[@iTeerRex]

@@BuzzingGoober No it’s not complicated. Most technologies are simple in theory, but producing “plastic” micro spheres, coated with conductive material, takes some doing. Are you a bot thinking your talking to a noob?

[@mattesmus]

I disassembled a lot of devices with lcd screens and always asked myself, how works the electric connection. Thank you very much for the details and well presented information which is also valid for a lot of your other videos.

[@msmith2961]

Love these close up dissections of common items where the SEM reveals details that I never knew existed

[@VincentGroenewold]

I absolutely loooove simple, yet brilliant in its simplicity solutions to a problem! Never even known about this, so thanks for that!

[@BreakingTaps]

Such a simple and clever solution to the problem! I assumed it would be some kind of complicated honeycomb/pillar structure when I first heard about it. But nope, just little spheres :)

[@thegeneralist7527]

I agree. The term I like to use is elegant. Simple, easy, cheap, reliable, fast.

[@dmeemd7787]

The work you do is just incredible man! Thank you so much!

[@muffinconsumer4431]

Why do they cover plastic spheres in metal, and not the other way around? Wouldn’t that guarantee that even if the balls touch each other all the way to another contact, the shells aren’t broken, and therefore cannot conduct electricity?

[@hasansawan4970]

I love how you casually said "if we turn on the element detector under the microscope". Then show the wonderful elements images effortlessly.

[@LuxGamer16]

Thanks for sharing, great video! I especially liked how you visualized the different elements. Really interesting!

[@gizelle-s]

This is awesome, thank you, I never knew that. I remember the rubber/carbon impregnated striped rubber strips they used to use to bridge the connections between the glass and PCB. How things have changed, but somehow also stayed the same.

[@jaypaans3471]

Cocktail nuts! That also shows why these connecting bits are so fragile: the conducting parts are absolutely microscopic, so any damage will mean a point of failure very quickly.

[@VictorF0326]

It seems like the crushing of the balls not only allows a larger contact area, but also makes it possible to have smaller balls that reduce the probability of the hollow spheres bridging to each other

[@BariumCobaltNitrog3n]

One of the best interviewers on YT is Brady Haran who has several science channels. Numberphile, Nottinghamscience, SixtySymbols and Periodic Videos and others. His genuine curiosity and really good questions (research) get people excited to talk about the thing they love.

[@SaccoBelmonte]

Wow....I had no idea this tape existed. The deposition of these conductive beads has to be one of the most precise tasks ever.

[@desi_bhai_]

this channel is my favourite channel, not because of the great informative knowledge, but because whenever i get interested in any topic their new video comes with same topic a few days later..

[@johnmcclane4430]

That zoom in shot of the spheres was great. Never thought about how these micro electronics were made possible.

[@PoorMansChemist]

I think what's far more interesting is how they manage to get those little spheres in the tape without them getting coated with plastic.

[@pahom2]

Finally I've got an explanation why you can repair an LCD display that has missing or glowing row of pixels by disassembling it and pressing the contact zone with a pencil. Until now it was like a woodoo trick that has weak hope on success. Now I see that it is actually a very straightforward solution and the issue itself understandable.

[@notapplicable7292]

Man this was an absolutely excellent video

[@AK-vx4dy]

In old electronic watches kind of sponge was used, it has repeating layers of ruber and graphite(?) thinner than space between contacts and it was put (not even bonded) between glass and circut board contacts.

[@BreakingTaps]

Someone just mentioned that to me: Zebra connections! I hadn't seen it before, but going to go dig through my old electronics pile and see if I have any laying around. TBH that's a lot more like what I was expecting from the ACF, some kind of pillar structure, not just random particles :)

[@andymouse]

Fascinating, I guess the unsung hero here is the coating and construction of the spheres as at this scale the odds of them touching and forming a bridge are small but even if they do the 'point contact' area on the sphere is ridiculously small ! so the ability to be 'crushed' and spread out a conductor is the key to this. I wonder could the spheres be an insulator but the insides be a crushable conductor ? It would work a bit like crushing a profiterole and the cream is conductive, but it wouldn't matter if the choux pastry touched as its an insulator..... I love it....cheers !

[@l0I0I0I0]

Yes that is amazing engineering!

[@creaturefpv]

Your a beast dude. I just found this channel but I am really enjoying all tye in depth information on a small scale thank you for the work you put in !!

[@Jacobk-g7r]

0:50 the same way we restrict time. Take some elements away and keep a direction. When really, time is emergent from all the pieces just like differences so time isn’t linear, we just chose to view it as that.

[@AFRFB09BA]

Thank you so much for making this video. I was curious about how this process worked when I tried to repair a LCD TV years ago.😀

[@stevemoore12]

I was having a bad day until I found your channel and now I'm learning something new and I'm blown away.

[@kylekirby6424]

I had always wondered how the ribbon cable was attached to the glass. This was great, thank you. I do want to point out that this video was recommended to me and I pretty much ignored it for awhile because the title didn't seem very interesting. Something better for me would have been "the almost magic tape that binds ribbon cables to your LCD screen"

[@SlyerFox666]

Well heat bonding is the solution the tape is a newer invention that doesnt last as long as it peels with heat and age.

[@rijaja]

The element detector looks absolutely sick

[@rikshaw2233]

The Levels of Precision required is just so fascinating. I've spent a couple years wandering. Thanks. 😎

[@benjefferson8609]

I've been working as an electrical engineer for 4 years, and I'm astounded how often I'm still learning new things like this 😅

[@Antney-u6j]

This is the first time I have ever seen any of your content and I am extremely impressed! This is the exact kind of thing that makes my brain so happy! Liked and subscribed, for sure.

[@bazrazin1]

the metal to glass connection has always been a mystery, had 2 monitors that developed vertical green lines , those who were saying it cannot be repaired were correct, also never in my entire electronics history had this knowledge of those micro spheres.

[@SantosHdzdank]

thank you, few people explain subjects in a interesting way never knew adhesive tech was so interesting.

[@MoisesCaster]

This is the best video about acf on the entire internet so far.

[@nkbp588]

The presentation of this video is simply incredible.

[@benjaminfens7870]

Was involved once in bonding ICs to glass. This video sums it up nicely!

[@aretorta]

It's interesting that the tape itself is isotropic, it's the pressing that makes it anisotropic. Wouldn't have thought of anything so simple.

[@NiffirgkcaJ]

This is amazing! Thank you for sharing this in a way that a non-technical person could understand!

[@michaelharrison1093]

Another cool product used in electronics is an adhesive thermal interface material that guarantees electrical isolation. This is a dispensible glue like material that cures and include small glass micro-spheres that guarantee a minimum gap when you apply pressure between the part that is being thermally bonded to the heat sink

[@rogerdeutsch5883]

Amazing and informative video. Amazed that you discovered that information about how those screens work and then clearly explained how it works. Subscribed!

[@Zuckerkome]

Super interesting! Reading the title I thought it was going to be some material science magic, but the principle is actually very simple and smart!

[@doodskie999]

Damn, there are a lot of things we just take for granted. Thanks for this awesome visualization

[@TeamStevers]

You somehow always pick a subject that is of great interest to me and I feel like I actually learn something, not just some trivial minutia.

[@andrewbrown6522]

Polymath channels are probably my favorite. You're doing a good thing.

[@Veptis]

Modern day microelectronics are amazing. I love to see this in the model and then in the wild!

[@smashtactix]

awsome video, very informative and interesting, I was and still am astounded by the in depth and detailed micro scope work and description you gave so that even a lamen like myself could understand it. I have learned a lot just by watching this, you have enlightened me, Great work. thanks for sharing this awsome content, glad the feed showed me this video.

[@ersetzbar.]

that is such a simple clever solution to a complex problem, wow

[@feedbackzaloop]

This is one very good example and explaination of a phenomenon I'm still very much amazed by: micro- and nanostructure production is so much more cost effective then mini scale! You set up the general properties of the process and physics does the job for you, while with conventional manufacturing, be it subtractive or additive, you have to think of speeds and pressures of every single movement of the tool and the reaction of the blank to it.

[@FedericoTrentonGame]

I havent subbed on a yt channel in probably over a year. i just watch videos and let the algo do the rest but your channel is really worth it. Good job man

[@trollenz]

Pretty cool and interesting video, love the sections... You put a lot of work into this and it shows pretty clearly. Thanks.

[@cyriacgc]

I just want to appreciate the effort you put into making this video. Thank you!

[@kalleguld]

That demo with Aloe Vera and ball bearings was so elegant. Great video

[@NEW_INSITE]

Subscribed. Marvelous work. I've been interested in electronics and science since a child. Have been in radio repair in the military and electronics as a hobby all my life. This was a great visualization and explanation of the bonding process. Thank you very much

[@johnk8825]

Fascinating information I will likely never use (@ 73 yrs old) but I am very glad I watched and learned, thank you.

[@GroovBird]

I remember prying open my lcd games as a kid in the 80's finding little pieces of rubber attached to the LCD screen that I believe served a similar purpose.

[@Chriss120]

the best demonstration of the principle i have ever seen.

[@augurelite]

Your videos always blow me away. I always learn so much!!! I'm super interested in this magazine!

[@twrandy]

My company produces ACP, not ACF, but the principle is the same. I like what you demonstrate in macro scale how this works. Just one comment, not all ACF/ACP makers use the "crushable" plastic balls with metal coating, actually Dexerial use sandwich particles (insulated skin+metal coating on core+core), Hitachi is most known to use metal coated plastic balls, my company use mostly dendrite or sphere metals, which are not supposed to be crushed. Normally we call adhesive with "conductive particle loading

[@zoo0602]

That small microchip is driver IC and connection points we call it Au bump. Usually made by sputter TiW and Au layer on IC’s Al pad (UBM layer) then plating Gold on it, also we have Cu Ni Au bump and Cu bump processing. In this video cross section is Au bump definitely.

[@EPMTUNES]

This is such a great explanation. Incredible visuals and editing.

[@DavidStruveDesigns]

Thats amazing! You wouldn't think just a couple of those minute squishy metal coated balls would be enough to allow enough electricity across to pass the signal or power across, but I guess at those scales you don't need as much contact as I thought. It's kinda also amazing that glass can have so many electrical traces running across and through it, and yet still remain perfectly transparent to our eyes. You'd expect the glass to take on a sort of frosted appearance but again, I guess just like bacteria and microbes in water - once they go below a certain scale in size they effectively turn invisible to us. Hence perfectly clear water ends up being anything but, once you view under a microscope.

[@MrHichammohsen1]

This episode was a rollercoaster to me! Brilliant work as usual.

[@AK2I47]

4:44 Good analogy this makes perfect sense

[@gordoncouger9648]

Diversity is one of the things I like about your channel. Interviewing wi;; work like most things one learns by doing. P would suggest you start by interviewing friends that are themselves good interviewers. Telling them upfront you're trying to learn and would like their help.

[@Rafael-ud2ul]

Your videos make my week. I really appreciate your videos !