Hi Just a quick follow-up video to my fax. uh, tear down the dumpster fax I got um I forgot to I was going to include this in the video I Completely forgot. So here's a separate Uh video looking at the linear scan head inside this uh fax machine Slm scanner copier. Now this is interesting.

The scanner head this module in here and I noticed a little drop- down latch there so if you push it, push it like that. it drops out. Isn't that neat? There you go. So there's the there's the sensor head.

that's just. it comes out nicely and it's got an illumination uh array in there and um, and the actual linear Um scan head itself. So oh, we could have a look at that under the Uh microscope. Now this is only a monochrome unit so this is not uh, a color I don't know how many gray scales it's got effect effectively.

Um, but let's let's have a look at how this head Works cuz it normally like it sits like that. just had a couple of glue points there which I've broken and it's basically got a bit of Glass on top. Okay, it's got I'll show you inside better in a minute because you can't see often see through the glass there. but you can see that there's some sort of array in there.

Okay, and there's some sort of like, um, you know, larger sections and that would be to let the light through. So if we actually flip this PCB off like this, you'll see that we got two parts to. well, essentially three parts to this one is, um, these little Channel things right? They actually go down and they've got a window which then goes down onto the paper because when you're scanning, of course it's you know it's completely dark in there. So you've got to illuminate the page and you've got to do it.

You know, consistently right across. Ross The board illumination is, um, like 90% of it. really? Um, if you don't get the illumination right, you're going to screw it up. So what they're doing as you can see down here, they've got little leads down there.

little. LEDs A lot of people complain when I call it lead here in Australia it's lead, it's not LED when I was a boy. anyway. Um, yeah, so let's let's let's take a look at the PCB down here first.

Okay, so you can see see H So I've got my Tano microscope here. We got 40 times magnification, but we will go under the better Olympus microscope later. You can see that is a little lead there, so leads spaced at, um, various intervals and they would simply light up through these uh channels here and then light up the page through that. so they're just all in series.

There are they just like a regular lead strip? uh, kind of thing. They've probably got a constant, you know, maybe a constant Carr driver there? Something like that. So that's the connector there. So let driving all that and then we've got whatever that is I don't know what that is.

Maybe that's a light sensor? perhaps I don't know I don't know if you know what that is. Leave it in the comments down below cuz I can't see any like you know there it is there. Does it actually like, can't see how it connects or anything? So I'm not sure what's doing there. That's not.

That's not the sensing array. The sensing array is of course all of these little tiny bits down here. you can see them and I'll show you under the microscope in a minute. but that's obviously the pitch between those will be the resolution of this thing.

So this is a line sensor array of of course. Um, so it's a CCD sensor array and it's got like one line. so it might have I don't know. 4,000 of these little Sens in CCD elements here.

4,000 of them by one. So even though it looks like it might have maybe two, one above the other. Um, that's not. That's not how it's going to work.

there's just going to be a Sens in element there. And then you can see circuitry on the uh, silicon above that. So if we get it out, it's all about exposure. really? there we go if I turn that down.

Yeah, so we can see the bond wire is going over to the various pads and whatnot. That's interesting, huh? And it looks like they've got the like in major groups. It looks like cuz you can kind of sort of see that they're split there. There seems to be like some split in it so it looks like it's coup.

I Don't know if that's like cuz they would like they would shift these out of course. so would they would have like there would be one big latch line that goes latch all of them all at once and then, uh, it'll shift them all out and then the steeper motor of course, moves the head across a tiny one uh, pixel forward and then latch scan the entire array, shift it out, shift the data out, and I don't know it might be 8 bits per pixel or something like that. So you know there a fair bit of data. Multiply that by however many pixels you know, however many thousands of pixels across, there's a lot of data that has to be shifted out quite quick from this linear scan head here.

and yes, and so they only need one pixel wide. And then of course that's why the scan head goes across the and if you've ever tried to stick your head in there, when when it's doing it, um, it's really bright and it it just scans across. and yeah, so it's got that little step motor there Go step step step step. Although it does it so fast that it appears as though it's like a a really, uh, smooth sweep across.

But it's actually a essentially a steeper motor in there that just steps at once and then um, and reads out all the day data. So that's really cool, huh? So there you go. So that's the array head. So yeah, I don't know what that's doing I I Yeah.

I'm going to presume, maybe like a light sensor or something. Now this is interesting. this. They've got these things here and these look like leads, right? They look like LEDs but there's not right.

There's nothing connecting these at all, right? There's no electrical connection to these. They they just sit in there so they I Guess they appear to be some sort of like lens kind of thing. But the pitch of those doesn't match up with the massively fine pitch that's along the actual silicon sensor head there, right? that's embedded on the D there. I Mean, you know you can't It's hard to see there like it's You know, well over an order of magnitude difference in the pitch between you know, these between the array elements and those um, lenses up there.

So they're not. They're not leads. So yeah, I these don't seem to be leads, right? Because these ones out here, they your leads, right? The little Bond wires go into them. So yeah.

I'm not sure how that's actually working there. I Don't know if you got any thoughts. Leave it in the comments down below, but you can see by the yellow there that it's actually these are actually um, see-through They're little seethrough like Windows lenses something like that. and the reason that they yellow is cuz they got a yellow posted note under it.

Trust me. I can I can see through that if I take away the Post-it note. Yeah, they're You know you can actually see through them. so that is rather interesting.

They're like little little bubble lenses at a way greater pitch than the sensing array there. there. There we go. You can see that.

Interesting, huh? So I don't quite know how that works. and they do actually line up. So these leads down here. These are these are going to line up with these big channels down here.

Okay, so obviously those leads just like you know, flood fill light in there and then it just goes on the angled plastic and then it lights up the paper through the bottom like that and then it looks like the sensor array actually does sort of like flip up over onto that bubble lens array. So it's interesting. I would have thought that that would distort it in some way. Yeah, I don't know my Optics maybe they maybe they do that for some sort of like Optical reason like I I couldn't even pull out the words off, the couldn't even pull out some wnk words off the top of my head.

But you know, refraction and all sorts of you know. um Optical type things. Optical is not my field so I can't even pull out some wank words there. but you know what I mean? Hopefully so.

but but that's interesting is it not? Um, that they have just sort of like an array I don't know if they're curved or what cuz they're actually embedded. Can I actually get that out? Hold on to your hat. I got the plastic out. No, it's not going to fall out, but I would have thought that would distort the image and that seems to be the only way that light's getting through to the sensor.

So that's interesting. So it must. you know some more patting. or you know, something.

something like that, perhaps. Oh, look at that. Got it? There you go. So we got the glass plate and then we got that.

It's quite thick, isn't it? Look okay. so it's kind of like an optical zebra strip if that's like for want of a better word. that's how I would describe it. like an optical zebra strip and they're like staggered there.

Yeah, if you know the name for that. I'm going to call that like an optical zebra strip because that that is fascinating. and that's really thick. That's like 5 mm thick and it's just like like light pipes.

just like staggered light pipes like that. But this sensor array is like an order of magnitude greater pitch than that. So I would have thought you know the little Brakes in there would have like distorted your image or something. but I don't know, please Optical Experts leave it in the comments down below: a huge 5 mm Optical zebra strip light pipy thing and that's the lens array that goes over your Optical sensor strip like that.

So once again, once so that kind of lines up for those being some sort of light sensor. Perhaps just to you know, uh, just to detect that the lights there and it's all even and I don't know. Maybe it can do some calibration adjustment for based on the light output or something like that. Perhaps for each individual section, but you'd have to do it on like a whole section basis cuz it looks like they only.

oh no, they probably got two there. It's an odd pitch. They don't seem to have two of those per thing over here. so I don't I don't know.

Not quite sure what's going on there. Anyway, let's go over the microscope and see if we can see down at the individual um, sensor and silicon. uh, circuitry level. And if I get that array under my Olympus microscope here, you can actually see that they're all.

They're all absolutely identical. These individual. uh, this is 400 Times mag I I think yes, I think I've got that right? Uh, and you can see that they're all identical. There's no, there's no filter, it doesn't appear to be any sort of filter on any of them.

Sorry, My stage is a bit how you're doing here. There you go. if you want to decode that, knock yourself out, they look absolutely identical. but there you go.

Um, so the difference between the pitch between those is going to be the resolution of the Uh scanner. obviously. So it's a, you know, however many pixels wide by one pixel. In this particular case, that's the actual.

that's the actual sensing element. I Can take it back to 200 times. Yeah. So there's a bond wire up the top there, for example, and got some extra circuitry up the top.

Whatever that's doing, scroll across there. Yeah, you can see one of the bond wires so nothing else doing there. Take that back to 100 times. There you go 200 and 400 Times Mag slightly off there.

It's not the world's best microscope, although it is quite capable. So it's interesting that there looks like there's a little array just above the El the sensing element there. There looks like there's a little array. Is that some sort of like buffer array or something like that? I I Don't know if you know your semiconductor layout.

Um, please leave it in the Uh comments down below. so that's interesting. Is it not? Um, yeah, There doesn't seem to be any extra uh, you know, filter or anything over the top of those Elements Which makes sense, They're just relying on all the external uh parts of that. This is just a linear sensor array and how many like levels that's got? How many bits? Um I don't know how many uh, gray scales.

Essentially, cuz this is not a color sensor so you don't see any. There's no RGB array. If this was a color sensor, you'd probably have three separate elements in there, each with its own RGB filter over the uh top. You could have like three in a line or three next to each other.

or however, it uh works. But of course, this is a fax machine. This is not a full-on color copier. so this is a uh, just a monocrome, uh laser printer and fax uh machine and scanner.

So it's not going to um, scan in color. So that's why we get an array and we don't see any uh, filter elements at all. But anyway, that's that's. really cool, huh? So if you like that, give it a big thumbs up.

As always, discuss down below: catch you next time.