2002 Mitsubishi Magna VR-X - 15.4" ultrabright LCD, fabricating... - Page 9

monkeyracer · 10-10-2007, 09:37 AM

I was thinking along the same lines as you were. The white in my opinion is absorbing some of the light (diffusing) where as the natural aluminum is reflecting it and aiming it toward the screen's diffuser. I think it would be worth setting up a scale test: make two small boxes, one painted white the other naked aluminum. Place an equal power led array in each, and cover the box with something that might resemble the screen diffuser. Then sit them side by side, and turn it on. The one that looks brighter wins.

Work is coming slowly on the tallskin, other projects going right now that are delaying the progress.

turbocad6 · 10-10-2007, 09:53 AM

if your theory was correct, then why do all lcd manufactures use a reflective white sheet instead of a mirrored finish? all lcd's from every manufacturer uses a white reflector sheet, I have never seen even one that uses anything but, I'm sure they spend big bucks on r&d & testing for best results....

I did find some reference material supporting this white reflector, but long ago, have no idea where I seen it now, but white is the way to go in my opinion

monkeyracer · 10-10-2007, 10:17 AM

I was just doing a little research on light boxes, and I change my mind, every lightbox that I found used white, not off-white, not ecru, not mirrors, but white. I think it would still be worth the effort to make a couple simple lightboxes to see visual results.

oh, and school busses used to use white roofs to reflect the sunlight to keep the bus cool, at least where I'm from they did.

monkeyracer · 10-10-2007, 10:43 PM

I'm doing a proof of concept to help you with this. I took some aluminum electrical boxes (think light switches, or outlets, the metal boxes behind the wall.) and some night lights. I sprayed one box flat white, the other chrome. When the paint dries, I'll put the lights in the boxes and compare. So we can see which is the brighter box.

sporty_drew · 10-10-2007, 11:50 PM

Quote: Originally Posted by monkeyracer

I'm doing a proof of concept to help you with this. I took some aluminum electrical boxes (think light switches, or outlets, the metal boxes behind the wall.) and some night lights. I sprayed one box flat white, the other chrome. When the paint dries, I'll put the lights in the boxes and compare. So we can see which is the brighter box.

lol i'm looking forward to seeking the outcome of this, are you just going to measure it by looking at it with your naked eye?

monkeyracer · 10-11-2007, 12:19 AM

so here's the pics:

It's hard to see the difference, but look closely, the light box on the right is brighter, and has more even distribution.

So the naked eye is the only measuring device here, since that's what's going to observe the actual brightness anyways. I don't have any fancy equipment, this is just a proof of concept. It seems the difference is slight, but this is a small scale example.

The winner is white (box on the right), it's just a little brighter, and more even. If this were done with actual LEDs in the scale biggy is planning, I'm sure the difference would be more noticeable.

So, biggy, it's worth the extra time to paint it white. (even if it's only for a few extra nits.) If my test is wrong (and every single LCD manufacturer too) then it will only be darker by a few nits. There's not really much to lose here.

BiGGy · 10-11-2007, 04:21 PM

Well, that was a fast answer, thanks for that test monkey, I was going to do that but you saved me the hassle. I don't quite understand how that works, maybe the whiteness acts as an activator rather then a refuser reacting on itself.

Looks like im going to redesign the box as perspex now and Im going to try and put a the LCD components and all computer components into the box. I think im going to shrink the depth to 50mm and perhaps with a slight taper to counter the dash clearance issues.

monkeyracer · 10-11-2007, 07:46 PM

I think from the tests, what it seems is happening is what LHC was saying:

Quote: Originally Posted by LHC

Your right in saying polished aluminium is more reflective, no one is denying that. However having it all polished aluminium will just reflect the light around for ever without actually illuminating anything. The white surface will 'capture' this light and glow in effect.

Not sure what the physics are here, but the proof is in the pudding.

afterdigital · 10-24-2007, 02:43 PM

hey biggy,

just browsed thru and i'm really impressed. Look forward to following this project to the end.

BiGGy · 10-25-2007, 05:28 AM

Thanks mate. Im going to start again very soon, im back home and going to setup my new workshop this weekend.

Found an acrylic fabricator in my area so im going to work on some CAD plans for this perspex case and give it to them to quote me. I want to focus some energy on the software side of this upgrade as well.

Fatal_Error · 11-18-2007, 07:06 AM

For a better light distribution, you might need a fresnel lens.

monkeyracer · 11-18-2007, 11:03 AM

Did he register just to post that comment?

BiGGy · 11-22-2007, 05:34 AM

Yes i know about fresnel lenses, although the screen already has its own diffuses. If I need more Ill get a fresnel.

While im posting might as well give a small update. Ive just planning out this new led (and now computer pcds) acrylic case and its on paper. Fabricators said they would accept paper drawings but i want to make an autocad version just to avoid any mistakes, still have to do this. In this box ill be incorporating an inside slim slot type of storage for the LCDs ribbon pcd ill have to fold back to make way for the lighting. Im trying to think of a fixture system for this but for now the plan is for it to be just sitting in there.

Its bean a large hassle getting a simple 12v voltage regulator that supports 2amps. So ive done a power calculation and I can afford powering the LEDs straight from the PSU which will give a steady 12v current for the 2A dimmer.

Im having trouble imagining how im going to attach the mount clips up the top of the bezel without taking the entire dash out. Still got to work out this but im going to get the new case done and mounted to the bezel before I work out dash mounting.

Found and cut out a double din bracket from an old p3, this will be fixed onto the bezel to support the removable DIN units.

When I sort out the above Im going to buy a fusion brain and try and integrate my climate control, amp on, external volume and a few other things.

Looks like im going to with a omni directional external antenna for the car, and a 24dbi home setup to get a local connection to my home as well as some nice wardriving range.

The above is pretty much all the physical aspect of the upgrade, this all should start rolling again soon with frequent updates.

In the meantime to support the costs of this install im in the middle of a production subwoofer box for my car which will be sold on ebay. Made from a two part mold I thought I might as well make some money from my fiberglassing.

and heres the most important part of the upgrade, considering all the wiring im planning to do myself I thought this is a must, will be getting one for the passenger side too.
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monkeyracer · 11-22-2007, 07:44 AM

If you need any autocad help, send me a pm. I've been looking a little more on the tallscreen skin, and I think I can get a working version soon, and build on it as time progresses. I'll post some progress pics later on that thread.

BiGGy · 11-22-2007, 11:58 PM

Quote: Originally Posted by monkeyracer

If you need any autocad help, send me a pm. I've been looking a little more on the tallscreen skin, and I think I can get a working version soon, and build on it as time progresses. I'll post some progress pics later on that thread.

So you have already started linking the buttons etc? Damn you work fast, I haven’t done anything on this skin yet lol. AutoCAD is a big part of my trade, I need to learn it and im starting a college class on it soon, need to prepare for it. If I have any questions ill pm you.