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DIY Projector Build


-22 June 2008-

Part Deux!

So where did I leave off? Oh yeah, I stripped a panel that I wasn't going to use which is probably best since I futzed it up anyway. It was an excellent training tool though! Plus now I have extra panel to make another PJ if I ever find a controller for it.

From this point forward all parts I use will likely be in the final design and all will have been bought new or used. I have had several people ask about cost of this project and whether it will really end up being any cheaper than a commercial unit. Some have down right talked shit about how much I'm spending on it, MrGrinch I'm looking at you. It is true that I have spent good money on this project already. It is also true that when I do a project, I like to use the best parts available. So from here on out I will do my best to list all prices for parts used in this build. I will also try my best to keep a running total of the project's cost. With that said lets begin!

Alright, what do ya say we work on something that will actually move me in a forward direction on this project? I purchased an LCD panel out of a Dell laptop from ebay. Certain models of Dell laptops, and possibly others use a WUXGA lcd panel in them. Learn more HERE. First a little background: WUXGA stands for Widescreen Ultra eXtended Graphics Array, this standard basically defines the number of pixels in the LCD panel, 1920x1200. This is in an LCD panel that is only 15.4" diagonal. Since full high def is 1080p (1920x1080) this monitor is more than enough to handle it. Currently, this is the smallest LCD panel available to us common folk that will still do full 1080p so, of course, that's what I had to go with in mine.

Enough of me, on with the pictures! First a shot of the panel as I received it. (Practice panel in background)

Cost of LCD Panel: $108.99 shipped - eBay

I had already pulled out all the little rubber nubs and unscrewed it so all I had to do was pull off the top half with only minimal force and fidgeting to give me this.

Then I just gently lifted the panel out of the plastic housing and laid it down.

Next was to remove the thin metal frame surrounding panel and holding it to the backlight assembly with tiny screws along the edge of the panel. The screws are the little black dots along the edge in the picture below. Now is also a good time to un hook the LVDS cable, that's the blue one going up to the PCB (Printed Control Board) at the top of the LCD. It unclips easily when you depress the spring loaded claws on either side of the connector. While we're here we can also disconnect that pink and white wire from the back light inverter. The inverter is that little PCB hanging off the bottom of the panel. Then we can unscrew and remove the inverter itself along with that black cable bundle hanging out at the bottom.

Just for reference here is a shot of one of the screws that held that frame on. It is sitting on top of my shitty RAZR phone just for reference. They are tiny! You ever had one of those jewelers set of screwdrivers and never had a purpose for that really tiny phillips in the set? That's exactly what is need for these things........ of course, mine was lost! Don't worry though I eventually found it and was able to strive ahead.

Now, if you weren't already being careful now is the time to really, truly, and for realz careful. See that giant sticker in the above pics that say "DO NOT TOUCH"? Ya, it's time to touch that, in fact we're just gonna rip it right off. It's best to try and pry up a corner of the sticker with a finger nail and just peel back nice and easy. If you have to cut it you better be damn careful because right under that big sticker is the FFC's, or Flat Flexible Cables. Pictured below, at the top of the panel, are 12 individual FFC's that connect the PCB to the panel. Sick of acronyms yet? Now I will say these are very fragile and you should be gentle, but having said that, these are not like gold leaf. They have some durability, it took a few instances of that PCB flopping back and forth, held only by the FFC's, before I had the bright idea to tape it down.

Next, you'll see a shot of the one side of the panel that also has some FFC's attached to it. These, unlike the others, do not have anything on the other side of them, they are simply tabs hanging of the side. Actually the traces in the FFC makes a u-turn and goes back in to the panel. These are equally delicate, but also can be touched or moved with out disintegrating. They seem to like grabbing a hold of paper towels when you're moving the panel so be careful of that.

In this next shot you'll see a couple of different things; remember that this is the back of the panel. First, at the top of the picture you can see the inside of the backlight panel which is made up of several semi-transparent plastic layers that help to spread out the light of the single CCFL (Cold Cathode Fluorescent Lamp) that runs the length of the display across the bottom. Next, notice the reflectiveness on the backside of the panel, this a reflectiveness we don't want and I'll explain that later. Finally, take a look at the top of the panel and notice the PCB has been folded out, but also notice that I have applied a strip of electrical tape across the length of the PCB to help reinforce the connection of the FFC's to the PCB. There is another piece on the opposite side. See, this is what I'm more worried about, not the FFC's themselves, but the connection between FFC and PCB. This connection will be the first thing to fail, so a good piece of electrical tape running the length of the PCB, stuck to both PCB and FFC all the way down. That's the best way to really reinforcize that up!

Here, notice the slightly metallic look to the reflection? That is there to actually reflect light back at the backlight if it is at a bad angle which is then reflected back off the backlight at the screen, this time hopefully at a more straight angle. This is done to actually help make the screen brighter. Unfortunately, for our application, most all the light that makes it to the panel is already going to be straightened out, so this layer is mostly just going to dim our picture. Therefore, it must go, actually it's two layers that will be removed after two separate soak sessions.

And what good luck I must have! Check out the corner of the panel, the reflective layer is already starting to peel off! Hopefully the rest of it is that easy to get off!

Alright, same procedure as before, cut paper towels to fit the LCD, soak 'em down, and apply to panel. Making especially sure not to let them go past the edge of the reflective layer. I used a piece of wadded up paper towel to apply more water when and where needed with good accuracy.

After about a 6 hour soak I think it was, I started trying to pick at a corner with my finger nail and Exacto knife. Without too much effort the top layer came off in a single piece. Sweet! Notice this layer is mostly clear and plasticy. Also, you may be able to notice a little graining on the panel around the edges from removing this layer. Don't worry that will all go away when the next layer's pulled off. So far easy peasy!

Back on the soak!

After probably 3 more hours soaking I began picking again. And up came a corner! And that's where the easy peasy ran out. This layer seemed much more reluctant to let go. I could have probably let it soak longer to try and soften the glue more but I was ready to peel it so it was going to be ready now too! I got my first glimpse of the mirror smooth panel underneath and decided this thing was coming off now. Notice the metallic look of this layer?

This layer was considerably more sticky, and more flexible, kind of rubbery. And it definitely wasn't going to come off in one piece. As I started pulling back the corner and the piece was growing larger the sticking force became stronger until I felt I was putting an uncomfortable amount of strain on the panel. So I decided to cut it at the edge so that I could take it off in smaller, more manageable strips.

The picture above actually is a good example of how not to peel it off. Proper peeling technique is to grab the piece and literally fold it over itself. The idea is to at a 180 degree angle of where the piece was so that you are pulling nearly flush to the panel. The inherent strength of glass is it's tensile strength, it's ability to not stretch when pulled laterally. What it does not like is forces perpendicular to the face of the panel whether that be pushing or in this case pulling. Especially with a panel this thin it will bow and break fairly easily. I found it worked well to grab one side of the panel and peel back in the opposite direction while staying horizontal to the panel. In fact, I had to pull pretty hard to get this layer off it was still very sticky. Kind of like this.

Here's a picture after it was all said and done. This layer even had a kind pearlessence to it. Pretty! No, more like just a pain in the ass, this was definitely the hardest to get off.

Ah, all that hard, delicate work, but the finished side is absolutely perfect!

So there you have it! Step by step walkthrough of tear down of the panel, followed by a detailed set of instructions on stripping the back of the panel. Ok, so this one ended up much longer than I thought it was going to, but oh well. On the next fun-filled episode: stripping of the dreaded front Anti-Glare coating! Then, I promise I'll go into what my design ideas look like! Same Bat-time, same Bat-channel!

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