Hi welcome to Tear Down! Tuesday I Thought we'd have a look at what's inside one of these lead LCD monitor panels. This is the one I got from the Uh Dumpster Dive 27 in. absolutely massive. It was, uh, cracked as you saw in the previous dumpster diving video.

But what's inside this thing? Well, we'll find out. and uh, yes, look, it is, uh, kind of warped there something. uh yeah. seriously happened to this thing when that photoc cop was uh, or that laser printer was dumped on it during in inside the uh dumpster.

What a bummer. But anyway, I've never actually taken apart one of these um LCD panels before. really and this is a lead one. It hasn't got the uh, cold cathode, uh fluorescent lamp in it, so it's going to have uh, some pretty good lead uh strips and may you know, a a diffuser plate.

um, something like that. some sort of diffusion technology to get a nice even backlight on the thing. So I expect probably you know to I'm not sure if they have it on all sides, but maybe on two sides like this, they'll have uh, some lead strips or something like that, and uh, diffuser plates and all sorts of stuff. So let's uh, crack this thing open or before we do, let's have a look at the PCB here and there's the main chipset on this thing.

It's a CMO CM 271 16a. Not going to bother looking it up, but there's some uh series termination resistors there and that comes from the main connector which comes from the Uh control board. So then you know that's the input and then this must fan out to all the other uh driver chips which then uh, go into these um flat Flex cables down here and they're they're solded on with a hot bar. uh uh technique.

So they come across with a hot bar down there and actually press down on these and they and it's solders these flat Flex uh strips down onto the board. There very common technique for this sort of thing, so uh, let's well, there's nothing much else on the board. There's a little uh low Dropout rig there or something. There's something else here that's a CMO CM 502 I'm not even going to bother to look these up.

um not too fussy them. oh look at that that looks interesting. looks like that's been. ah look, has that fried? Has that been fried or has it been reworked? I don't know, something's gone wrong there.

Maybe that it's what. that's all that was wrong with this thing. I mean it is actually uh, shattered the panel, but that's maybe why it was originally dumpster dived or dumpster tossed to begin with. It's almost as if something's gone horribly wrong with that chip there.

I think maybe that's uh, died a very s s death I think so maybe? Yep, that's what the reason that this thing's been tossed out? perhaps? Who knows. Anyway, let's not speculate about that. some DC to DC converter stuff. Big inductor here.

lots of parallel uh caps here. tons of them really getting the uh inductance down there. and uh, there's not much else on the board so let's take it out and uh, flip it over. One of the interesting things though, is this is a pretty darn long board.

It's like 55 cm long. so you know, um, they, they've really, uh, gone to town there of course. Um, you'd have no problems having this, um assembled through the assembly machine. usually cuz length usually isn't a problem.

it's usually height. um, inside. you know, certain width inside the uh, pick and place assembly machine. but usually they can do any size, uh, length like this.

but uh, sometimes you will not. Um, some bear board manufa facturers won't be able to make a panel uh, that big and uh, they interestingly I can't see any uh, breakout tabs V groving or anything like that. That board looks fully routed on all edges so it looks like that just that individual board has gone through the pick and place assembly process or more likely they would have done like a well. it's a fully routed board and then they've done like a custom jig like they would have had like a they would have you know made a custom uh, plastic jig or something like that to hold the board in place.

and they would have had multiple channels like this. So you know, maybe they had five boards stacked up like that and five boards then moved their way through the pick and Placer assembly machine. But let's uh, flip this sucker over and see what's on the bottom side. Well, that's surprising folks.

Look at that. Absolutely nothing on the back there. No extra drivers or anything like that. just a whole bunch of uh, parallel, uh, tracers running the full length of this thing.

So uh, there's got to be, uh, some more circuitry on the back of this panel. That chip ain't going to handle everything folks now. I'm not actually sure which order to get this out. There were a couple of screws along the bottom here, but that's it.

There's no other screws like along the side down here. It seems to be helding place by some uh Clips So sort of get in there and sort of lever it out and uh, it looks like should just pop out. Well that's the. uh, that's the plan.

Anyway, here we go folks. Tada Ah, pop back in. Bummer. there it is.

Ah, got it. finally. Aha, there's our white, uh, reflective back in I would say or is that a no? I would? Well, yeah, white reflective. I Guess they're not going to make it silver, so that's so that the uh light reflects back evenly off the back of that.

So there we go, have quite a nice I'm not sure what that is. Not sure what material that is probably has a high reflectivity. Be great for my uh white balance. so I can set actually.

yeah, I might keep that I'm assuming it's uh Pure White it looks Pure White to me could use that as a nice white balance card for my camera. That' be neat. So we have that and now we have. Ah and this has a nice I'll get the macro lens out out in a minute.

You won't be able to see this but that this has a nice back in on. this has an etched pattern on the back of it here. I Can can feel the etched pattern on it like little little dots. They are tiny little dots and these are so I still can't see the leads in here.

um which is really kind of unusual. There they are. do there we go. There's our lead strip all the way along the bottom.

Should have known that there's our connector. There we go. There's our lead connector and there's the lead strip all the way. so it's only one side.

I I was wrong I Thought it'd be on both um edges, but it's all it's coming from. The is that the top or the bottom? I'm not sure now. anyway. um, it's just coming from the top or bottom.

That's a really neat lead strip though. um, presumably I'm going to oh I'm going to take that out. Um, they're obviously not going to be in. uh well, are they in.

series? How many is on there? If you wack up in series and you uh, you know, 3 volts per lead, that's going to be an awfully high voltage uh array. Otherwise, if they're parallel, they have to have a current sharing resistor. and I oh yeah, yes, oh know, no, that's silk screen. I'll get in there off the macro I thought I saw a current sharing resistor for each one, but there's not I don't think it's on the bottom so I'm going to assume that they're all in series.

Well, we can measure that later. That's going to be fun. If it is, we'll uh, get out the high voltage power supply and uh, Power this sucker up, by the way I didn't get the part number on this one made in China it's a Chi Me Opto Electronics uh brand panel. Whether or not it's uh, you know, just a rebadged from one of the major Uh manufacturers.

I've got no idea if you've got any details on that I guess I could Google it. but uh I won't bother at the moment if you do have any details on exactly uh, who manufactured this and what plant. uh, please leave it in the comments. So this is our light guide and uh, these are you know, fairly, uh, simple in terms of their um, uh construction.

I'm not sure the exact material, some sort of, you know, polycarbonate or something like that nicely machined edge here which goes along. the Uh leads at the bottom here and at the top, they've got a White Strip on there which is the same as the reflective strip which sits on the Uh back here which you saw before this one here. So here's our reflective strip sits on the back like that and then uh, of course the light shines in here and then it bounces off well due to total internal reflection. It uh, it acts as a light guide and it's reflecting in and out, in and out all the way, will bounce in off the top and bottom edges until it hits all these little dots on the top which we'll take a look at and they're the thing that actually reflects the light.

Then out the front like this and we can see that on this. Dave CAD Drawing here we've got our LEDs at the side here. this LED strip. This is our reflective film.

that white reflective film on the back. These are little Uh dots. I I Presume they're like a chemical etched or something on the uh back of there. I'm not sure how they actually manufacture the uh, tiny little dots on the back, but anyway, um yeah, this effectively works as a light guide.

So the light Shin into here it'll be the correct thickness and they choose the correct angle lead, blah blah blah to get the Uh total internal reflection in there as best they can. So the light bounces all the way around in here and sometimes they'll hit these little dots here. Well, a lot of the time they'll hit these little dots here and then the light goes out the front like that at various angles. Of course it doesn't, just all magically go straight out like that and uh, that's what um uh produces the light coming out.

So this is how they can get a, um, an even light coming out across the whole panel from just an edge lit down here. and there's multiple ways to do it with. um, you know, either you have ones on multiple sides or you have like all four sides. but I think most these days only use the one side like this so that's effectively how these things work.

Very simple, but then you need some extra stuff on top of here to really like. You need an extra diffuser plate and extra stuff on here as we'll not out see to, then get a nice even diffuse light out because otherwise if you just had this, you'd actually see little bright, you know, spots, You'd see all the dots. Um, if you don't have the diffuser plate and other technology which will be on the top of here, there you go. You can see the little individual dots there, absolutely tiny.

and uh, yeah, as I said, I'm not sure how they're actually uh manufactured, Whether they're uh, uh, you know, chemical etched, laser etched, or you know something else. I Don't know if you get got any uh um, info on how they actually, uh, manufacture those dots on there. Please leave it in the comments and then below that we have a nice diffusion layer. Look at that.

So um, actually this is where a lot of the Uh technology could be in this uh, diffusion film. Here you can see it, you know it is quite diffus. So there could be more technology in this, uh, thin diffusion layer here than in this uh, polycarbonate uh uh bit here. So I don't know if anyone has any exact uh, details and stuff like that.

Please let us know. Oh look, there's another look at that. There's another very you can just see my fingers. well it actually turns up much better on camera.

Looks like it has lots of magic in there. Timey Kangaroo Down SP timey kangaroo down This film is very interesting folks. Look at this at a really uh, shallow angle. Like this it is H quite transparent.

You can see my watch and my screwdriver through there, but if I move it up to be directly vertical to it, it absolutely vanishes. and as I bring it down the angle again very shallow angle. again you can see it's transparent again. but you bring it up that's like 90 to it.

Completely opaque. Look at that and that only works in uh the what I'll call the uh the y direction here like this if I actually spin it around on the X Direction like that it actually vanishes. No, that's not just a trick of the uh camera or the light reflection I can't see that either. so you go over the top.

and yeah, so in the X Direction it is only transparent at shallow y angles like that. Interesting. So it's no surprise that the lead strips are along this bottom. Edge like this so that is really quite fascinating.

and no, it's not polarized if I you know, uh, move the you know, watch around like that or anything like that. I Did a quick little uh bit of research on this film stuff and uh, it turns out it's called Uh prison film or lens film or if you get it from 3M who's the main patent holder on this stuff it's called brightness enhancement uh film or BF and it's 3M micro replication technology and it basically uh well it says it recycles the Offa light. So as I said before, all this light the light source. These are the individual dots down here that are you know, uh, shooting all this light out in multiple directions.

It just helps channel that and improve in boost the brightness. Um, if you only got one piece up to 60% two pieces up to 120% so it it increases the brightness um as well as um, you know, channeling it all directly and outwards as you can see it improves brightness, contrast, uniformity. and Energy Efficiency very vital part of these LCD displays and that's exactly how they work. Some of it gets recycled back depending.

Oh, you're a bad angle sorry, you're coming back in and some of it might even bounce outside the little prisms. and that explains why by the way that we could actually see through it at a shallow angle in this direction and this direction like this and of and we couldn't see anything in this direction because they're only manufactured in you know, a long sheet like that. So they're Direction o and we actually have some data as well. Here's the uh gain of it and uh, you can see at uh, the larger angles, it just completely drops off like this either side of that.

So there you go it those into all your light and Optics uh, physics stuff. You could have a fi day with this. and as I said, 3M hold uh like a lot of the patents on this um stuff but it seems that some of those are expiring so there's other manufacturers coming into the play as well using their own technology and you can get different uh types of got standard 9 round tip wave you know and they all have various properties. I Have no idea uh which uh this one is but it is definitely one of these uh prison films or uh, befs and what's our final layer on here? Tada So we're not done yet.

There we go. We have three layers of material. I'm not sure that's sort of that doesn't look to be that doesn't look like it does anything at all, just maybe a little extra diffusion layer or something like that doesn't seem to be doing anything special anyway. So we've got three layers of uh, diffusion.

you know, slash uh, you know, reflective, reactive type of material. plus our lead panel as well. plus our light uh, guide panel as well. So absolutely fascinating construction and pretty much what I expected I Expected there to be a lot of technology in the uh in the LED diffusion of this.

Yeah, here we go. Here's where we can see our cracked panel folks. hi I can see myself. it's very reflective.

There you go and uh, not sure if you can see those cracks, but yeah, probably getting some of it in there. but yeah, it's cracked all up here. All the glasses cracked everything. oh I shouldn't run my finger over that.

Sorry, yeah, all you Apple fan boys getting excited sorry I'm not an Apple fan. This was given to me by a fan who uh came to visit the lab who uh works at Apple so that's why I'm wearing it and it's kind of. It's all right I like it even though it is Apple but uh yeah, now we can see all our little individual pixels in there. But we've got our cracked, well, and truly cracked glass panel.

So here we go: I Can take out the plastic surround on that. came out very nicely, but you can see how it's all. You can probably see how it's all cracked. Yeah, you can see all the crack marks up there.

and uh, we saw that in the previous video. But yep, there's all our uh, there's our tiny little driver chips. Well, they're actually huge, uh driver chips. but uh uh.

tiny in size. The trace spacing down in there is incredibly small. But yeah, so we've got uh 1, 2, 3, 4, 5, six, 78 for the uh, uh, X Direction and uh, one, two, three over there for the Y. And it is interesting to note that there was no extra layer in there.

That's it. That's the front. Uh, that's the front panel of the things. So the actual panel itself is, uh oh yeah.

I can see the cracks in it now. if I uh, look at this Uh panel at the right angle. There we go. You can see them all the way down there.

So this, um, so the actual uh LCD panel itself is, uh, the entire front. uh, surface. There's no way. I I Expected there to be an extra protective film on there, but uh, it's not.

It's all. uh, it's all embedded and integrated. Although this film does seem to be an extra layer stuck on there. so maybe I can attempt to, uh, peel that off? Perhaps I Don't know.

but there's a lot of layers that go into the construction of these panels. Let me tell you there. Yeah, yeah, this could take a while. Here we go: I Got it.

I Got it? There We go. That's the front protective film. Some sort of polycarbonate. and yes, that is the uh top polarizing film.

Check out my fluke 87 as I turn it around Tada it vanishes. So that's the top polarizing film. There will also be a polarizing film on the bottom of the Uh LCD as well. So yeah, that extra layer on the top here.

that'll also be the uh second polarizing filter on the back. And then if we go in, we can start seeing all of our pixels. Fantastic Look at that. Ah, beautiful.

That's actually rather fascinating folks. This is with my Times 10 macro lens and you can start to see the individual red, green and blue pixels in there. And they would of course this is a TFT screen that all have their individual uh, driver transistors and then all of this looks like purple stuff here. These are all the actual traces leading up to there.

so there's like you know, 100 little traces in there going up to your individual um columns there and there you go. That's one of the driver chips. Take a look at the trace spacing I'll zoom in on that in a second. but those, yeah, there's they are all tracers in there folks.

they are all tracers. Look at them all the tracers coming out here, wraping around going up there out of here, driving each individual uh column in this case cuz these are the X drivers. So there you go n and there's the part number on that sucker and look at the traces. My times 10 macro lens is not good enough to get down there and look at those tracers.

I can see some of them. You can see some of them in here. This is where the DAT is uh, coming in probably. but all the output drivers for the individual pixels n can't see a damn thing.

And it's not surprising really because if you do the math, uh, there's eight of these chips. um, driveing all of the columns and of course this would I believe this is a full HD 1920 by uh, 1080 uh panel. So we're talking 240 traces each. one of those chips has to drive.

Count them, folks. Oh I Can just see them. just if you watch this thing in. HD you can probably just see the individual tracers in there.

That's insane. So there you go. If I Bring that in and out of focus, can just see the individual traces. Absolutely tiny.

Woo! You can see how these flat flexors are all sandwiched inside the uh, polycarbonate. I presume polycarbonate layers or some such in there there. You can see the tracers going around there and then right up there to the road driver. Uh thing.

let's see if we can zoom in on that so you can really see those traces on the inside of the panel down in there. and then it comes up and there's our there's our road driver chip. You can just see the number down in there I don't know if you can find info on that I'd be very surprised, but you never know, never know what Google oh one. Anyway, I wonder who uh, Novatech is, whether or not they're just you know, manufacturing the flat Flex assembly or whatever.

or uh, they have more to do with it I Don't know and you might ask, well, what is that pattern up there doing? absolutely nothing folks? I don't know. Maybe they're just doing some uh uh Equalization to put some extra copper in there so I don't know it doesn't curl or do something else funny I don't know. they've taken a few Liberties there, that's for sure. and my first guess would have been that they are test pads of course, but uh, you can't access them because they got the film on top.

So um I don't know. maybe um, uh, during the manufacturing phase before the final Fil is put on the uh top. Perhaps that's all I can think of. and if we have a look down in the bottom corner down here, check it out.

You can see the individual traces going in. or it's actually it's really hard. but uh, you can. You can see the individ.

Oh my. Screwdriver is massive here. See the individual tracers running up and we should be able to see the uh, red, green and blue individual uh TFT transistors. And there you go.

folks. looking through my microscope? Really difficult cuz I've got my camera with the macro LS right up to the eyepiece of my microscope. Not fully equipped for this sort of stuff, but you can see the individual red, green, and blue pixels in there. Not a problem at all.

Beautiful. There's more of them down in there. I've got to uh, shine my torch right across this thing at a very shallow angle there to get this shot. but that's amazing.

Look at that. There you go. That is the bottom corner of the panel. You can really see that quite clearly now.

Individual red, green, blue filters, and uh, the drive-in transistors are all integrated. So you can go into all the theory of how these Tfts actually work. and there's you know, slightly different uh, manufacturing, uh, uh, processes and things between manufacturers. They all.

They're all going to have their own uh, bit of secret Source in there somehow. but you can see those tracers coming in from the bottom there and then driving the uh, the rolls on the bottom. There, it's it's on an angle, it's on a 45 angle here of course. and uh, but it it is rather is rather fascinating.

Oh, I've moved it. Let's just move across and uh, there you go. sorry about uh, the movement here. I'm just trying to hold my camera and tripod in place while uh, focusing this microscope.

but that is incredibly interesting folks. And on the front side of this, you can see that they've got some sort of blue Gunk around the outside, whether or not that's s of part of the Uh bonding process for all the various Uh layers? I'm not entirely sure and on one corner of the panel here, look at that looks like we have some sort of test connector now. I Won't actually go into detail on how the Uh Liquid Crystal uh TFT panel itself actually works. There's plenty of tutorials and with great graphics and everything out there to explain the operation of uh, these things.

but uh, and in terms of how the liquid crystals work and all that sort of thing. But basically what we've uh got is the uh diffusion uh plate at the back. The white light as we've uh, seen it generates like an even white light at the back of this panel. and then as we saw on the Um Underside here we have a polarization layer so that actually creates uh polarized light light which then enters the uh, TFT panel itself and then the TFT panel.

The individual Uh pixels in there red, green, and blue. They have red, green, and blue filters. Well, they're not the pixels. Three of those red, green, and blue elements make up one Uh pixel or one picture element.

and then when you apply an electric field across each Uh pixel element, a red, green, or blue. uh, one of those. Then you can individually, uh, turn on or off the polarization of the light passing through the individual red, green, and blue elements. and so, uh, you can actually uh, block or allow the light to come through those red, green, and blue filters.

and then we've got a final polarization uh filter on the top here. and then that's the light that ultimately comes out. You can turn on each of those things. so all it is is Uh.

Either allowing the light to come through from the backlight or not for each one of those uh, Uh, 19, Uh, 20 by Uh 1,80 for full HD screen, red, green, and blue picture elements. and it's you know, it's remarkable. Just the density in the technology in these Uh panels. Absolutely phenomenal.

As you, uh, saw, in terms of the Uh Trace spacing and things like that, Well, I Tell you what. these LEDs seem to be. very, very efficient folks. They're uh, incredibly bright.

That's just my multimeter diode tester. uh, doing that. You can really see see the pattern emerging now at that. two.

three just lit. but that's absolutely incredible from my uh multimeter. And that lead board was quite a mung to get out too. It was all stuck down with double-sided adhesive tape on there.

and uh, but this is a very, very long board, folks. just keeps going and going and going and going and going. That's one hell of a strip. And for those playing along at home, 61 cm long and you can see the Uh traces on the back of that.

they got a patent on there I solded a couple of Uh wires on here just so that we can, uh, have a go. There's basically two uh ground pins in there basically plus uh, four uh signal pins. And there we have it folks. I've got one strip fully lit up that's at 10 milliamps using my key the 225 current Source let me, uh, put constant exposure on that and let me, uh, change the wick a bit.

Let's go down to that's 8, 7, six, that's 1. Milli oh sorry, that's uh. there we go. We're 1 milliamp there folks.

that's not much at all. I mean let's even go down less than 1 milliamp, that is 0.1 milliamps should still be able to see that. And of course, if I turn my uh lab lights off, that might help a bit, but you can still see hopefully those lit up on camera there and that's at 0.1 milliamps. Unbelievable! So let's turn it all the way back up to 9.99 milliamps and uh, that is super duper bright I like it and uh, of course it takes a reasonable amount of voltage to do that and uh, but I can do that because I've got my uh I've got my Keithly current Source over here which I'll show you.

So of course it's really handy having this uh, Keithly current Source Not only can you dial in the uh, constant current you want, but you can dial in the maximum voltage there as well. So I don't know what the maximum current is I mean that is 10 milliamps and that's quite bright, but obviously not bright enough to do the panel. If I had the data sheet for these things, I'd know I mean I can go up to that's 90 milliamps. That's pretty much the maximum that my Keithly current Source can go up to, but that's incredibly bright all right.

So what happens if I put 20 milliamps through this thing and then put on the light guide with the diffusion layer on there? obviously I haven't got everything lined up. It's not perfect I'd have to put it all back in there. eh. doesn't do much at all.

That's pretty boring actually. there's the Uh back side of the diffusion layer down there. but yeah anyway I have to do some better uh experiments with this thing. I could like take out individual layers so if you want me to see do a like a separate video on that I uh I probably can cuz I I've now got uh all the stuff to experiment with that and it could be rather interesting taking out the individual layers and seeing what effect they actually have on the on the total uh diffusion of this thing.

So anyway that's a quick look inside one of these modern uh LCD uh monitors of one of these lead uh, backlight ones. So lots of technology in the uh diffusion layers and all that sort of stuff that that technology has advanced a lot if you remember sort of notebook LCD screens from uh you know, many years ago or not that many years ago, only 10 years ago or something. you know you get the bright spots where you could see the well, they didn't have lead technology back then. of course they uh would have the um cold cathode uh stuff but you know I mean you would see the hot spots and everything on the side and it wasn't really nice and even and diffused like these are um you know you take for granted that uh you just get these nice diffuse things these days.

well spare a thought for the technology that goes into all these layers and stuff. and if you do have data sheets on uh uh, all this layer material and everything please uh post it cuz that would be uh, fascinating. And there's tons of technology which of course you know 30 years of progress or something has gone into. uh LCD Technology like this just absolutely incredible.

the tolerances and you know, full. HD and ah it's just absolutely amazing stuff. But anyway I Hope you like that and if you want me to play around uh with it some more, please let me know all this diffusion stuff and if you want to discuss it, jump on over to the Eev blog. Forum If you like tear down Tuesday you know what to do.

catch you next time.