[john] mentioned this on the LCD LED backlight post. Given the date on the posts, I was surprised that we haven’t seen it before. He replaced the CCFL lamp with 32 1 watt luxeon LEDs mounted on a custom copper water cooling block. The result is bright enough to be sunlight viewable in his car.
He mentioned CCFLs at the beginning, I was going to say CCFLs would have been a better choice but it looks like I might be wrong. Supposedly the short tubes would only get 20-30 lumens/watt while the luxeon LEDs he has are 35 or 45 lum/watt.But I still think that huge watercooled heatsink overkill :p.
Whats the efficiency of the luxeons in terms of heat output? I’m sure 15-30W passive heatsink is not too hard to do.
Posted at 1:47 am on Feb 1st, 2007 by japroach
This “hack” sucks. For how many times have people now posted “LED backlight” “hacks” here? What this guy did is- mildly speaking- total overkill. Copper plate? Liquid cooling? WTF? Why not use CCFLs? Just to show who has the biggest penis? There is no advantage of his design, its just monstrous, and that itself is no achievement. He sounds pretty arrogant on the forum too… nxt pls
Posted at 7:24 am on Feb 1st, 2007 by jimmy-the-fish
Wow 32 luxeons, that person must be swimming in bling. Daylight readable is a good feature to strive for though
Posted at 8:22 am on Feb 1st, 2007 by DoctorWhom
Hey will its been a month since the contest was over, so i would like to know when are you goning to announce the winner? thanks!
Posted at 9:48 am on Feb 1st, 2007 by pabloec
jimmy-the-fish: he said he tried multiple CCFLs and had trouble getting multi-tube inverters/dimmers working right.
In the end he went with a boe-hydis HT12X21-210 wide-angle LCD, which he claims he doesn’t even have to use the LED mod for, but when he does it looks *stunning*.
He doesn’t sound like someone who is arrogant to me… but anyway.
Posted at 10:06 am on Feb 1st, 2007 by akmixdown
Of course he did, akmixdown. If I spent $500 in LEDs for a project I’d say that the result looks nothing less than stunning.
Posted at 10:57 am on Feb 1st, 2007 by Pokey
I think the reason for the water cooling is to make sure that the LEDs will work in a 125-150 degree F ambient temperature. Also, you don’t want to heat the LCD unevenly, or you’ll get spots. Plus, a good portion of his work is install time… it’s often best to overbuild it so that if there’s a problem, you won’t have to rip it up, rework it, and reinstall it later. Watercooling makes sense for constrained places & to keep noise down.
A bonus of the LEDs is that they can provide a wider color gamut over CCFL. That would partially depend on the color filters in the LCD, but I’m sure the results would look stunning.
It wuld cost even *more*, but he should have used Cree 1W LED’s, they produce TWICE as many lumens as the luxeons, but with the same heat/powerusage. which means either a)he will only need a few, and b) the sky is the limit as far as brightness. The Cree (7090xr-e, i think its called?) can produce 135 lumens/Watt. If he uses only 12 of these babies he’ll have the equivalent of a 100W bulb beaming through his LCD- with practically no heat. Plus, the light array will last for 5 years 7 months of solid runtime (50,000 hour lifespan at full output! From another angle, on any normal LCD screen you could use just 8 to match what his grid produces, with inconsequential power use.
ps-japroach: luxeons were at that point 35 lumens/watt, they are now 50 (with the Luxeon V).
Posted at 4:30 pm on Feb 1st, 2007 by Eurisko
I love the comments on this site. If you guys would actually look at the end of the project, it looks quite good. He’s not going for theater quality, he wants to be able to still read the thing when the sun is hitting it. He’s also water cooling it because this car pc is actually a couple pcs and he wants to get as much heat as he can outside the car.
yeah the comments seem pretty bitter on this one — I see this guy as a doer and less a talker… I know I’m a talker, but I get some things done. My single biggest problem (besides getting over my inertia/laziness and starting to build) is that I *SUCK* at enclosure fabrication and mods. Does anyone have any decent links on doing the type of thing this guy did with the plastic modification?
I can see he built up the areas he cut up with some kind of bumper epoxy and then sanded it down, but there’s got to be more to that, especially when it comes to smooth, straight edges.
Posted at 8:06 am on Feb 2nd, 2007 by akmixdown
@akmixdown:
From what little I know of automotive repair, working with bondo (bumper putty, etc…) is that it involves a *lot* of wet sanding with fine grit sanding blocks. It’s easy to screw up, takes a lot of time, and probably as much practice; but it’s also easy to fix mistakes (use more putty).
I’ve never heard of doing this for interior work, as I reckon it’s messy as hell; so he probably removed the center console bits and did it in a shop.
Another technique is to mold and cast like this guy did:
http://homepage.mac.com/reelmagik1/PhotoAlbum3.html
(apologies if that’s been posted here before)
Posted at 12:50 pm on Feb 2nd, 2007 by pragma
hey guys, thanks for the compliments & critisizims:)
akmixdown, you can see the fabrication I did better in another screen that I did:
http://mp3car.com/vbulletin/showthread.php?t=85350
also guys, keep in mind that a digital photo isn’t the best way to really see the results of a really bright screen, in person this screen does look great… a regular lcd will be impossible to use in direct sunlight… it can be bad enough that you can’t even tell if it’s on or not even… this mod I did was to be able to see & use the screen even under the brightest conditions, & the end results are that the screen is usable at all times… I can see it during the day even with my sunglasses on, which was the original goal of this project…
Posted at 3:48 pm on Feb 3rd, 2007 by john
awesome writeup on the bezel… I might have to try this. :-) Thanks again.
Posted at 4:20 pm on Feb 5th, 2007 by akmixdown
It would be awesome if you could post where you got all those luxeons, and how much they cost…
Thanks
Posted at 12:33 am on Feb 6th, 2007 by Ice
I bought them a long time ago.. it was from ledsupply.com… I think it was a one man show, always talked to a guy named zak…. he was real helpful..
back then they were over $9 each, & theres a special power supply that can run up to 12 of these in series… I use 3 of them… they were around $30 each… I think the prices have come down a bit since then, theres newer stuff out now….
someone mentioned the cree’s.. great lights there, but they weren’t even available back when I did this…. that & you’d never get enough dispersion trying to just use 8 or 12 of them, edge lit maybe, but not rear lit….
optics & projection patterns come into play too, as well as distance… you have to focus an even overlaping pattern or you’ll just have a bunch of hot spots, meaning more diffusion necissary, meaning even less available light
something like this could be done with a fan instead of the liquid cooling, if you don’t mind a fan that is… to be totally passive & burried in a dash would require too much surface area of the heatsink, & in a tight spot like that it would eventually get heat soaked, you would at least need some airflow I would think…
these lights are better the cooler you can keep them, & there life span is directly related, as well as there brightness level, which diminishes as there run too hot… mine will last many years & maintain there brightness decently at least….
this may be a bit overengineered, but it’s built to last & work well for a long time
Posted at 11:12 pm on Feb 9th, 2007 by john
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Cool, but I don’t like forum posts…
Posted at 12:35 am on Feb 1st, 2007 by Crash