I have bought myself a new 720p 3d ready projector, which is so good, that I will probably burn out new lamp in about 2 years (its rated at 4000 hours). Has anyone got any expirience what it takes to mod a projector to use LED as a source of light? I know it will be much dimmer than original 2500 lumens, but it should be watchable in complete darkness. There are budget comercial LED projectors with rated 200 lumens (I think this number is not measured out of the led, but after light comes out from the projector) and by looking at the videos on youtube it seems those are bright enough.
I will project max 2m x 1m, that is 2 square m or 21 square feet and minimum acceptable screen brightness is 16 footlamberts, so I need like 21x16=~340 lumens out of projector. I dont exacly know how much light is lost due to the optics, but I suspect losses are probably high... I was thinking something like 4 or 5 hard driven R5 LEDs could do the job. Also optics/reflector will be a problem. Are there any kits to fit into bulb based projector? How many hours would hard driven (at least 2A) r5 LED last?
Thanx for any suggestions!
This is exactly what the SST LEDs were designed for. A properly driven SST-360 (Quad SST-90 dies) should be good for 6-8,000 lumens. (About 40 amps) Worst case on the optics would be about 60%. I'd look up the lumen rating of the bulb that is in it - should be findable from the manufacturer's website.
I'd also wait at least a year as the XM-L LEDs will then be freely available and will eat the market for the SST-50. The XM-L will do at 3A what the SST-50 does at 5A.
Thx for advising SST-90 - what kind of driver would I need to get ~10A to the SST 90 LED from something like 19V notebook power supply?
I know how to baypass balast of the projector, I also know I need some big aspheric lens - like this one: http://www.dealextreme.com/details.dx/sku.13618, LED sst-90 and some big cpu heatsink on it. I think only driver could be the problem...
This is a highly nontrivial problem. The optics to produce an even field of illumination have to be redesigned. The image color has to be recalibrated for different spectral output. Mechanically, much of the layout may have to be remade.
Frankly, if you have to ask whether multiple cree dies would work, I dont' think this is a feasible project if you're looking for a replacement. You can however probably do something fun/neat and it's not difficult to make a projector that kind of works. For example, projects of this type tend to start with a larger imaging panel because it's in some ways easier to produced an even field over the area (that and monitors are cheap), the sub 1" ones in commercial projects are less forgiving of the larger tolerances in hobby projects.
That said, an led like the sst's seem ideal for this kind of purpose because it's pretty even illumination in the first place.
Personally, I'd say go for it if the intent is a learning process, but skip if it's just to save money because it likley won't be great value.
This thread is quite educational http://lumenlab.com/forums/index.php?showtopic=24619&st=650
A lot of noise, but also a lot of lessons learned.
It seems even a sst-50 should work out ok if you don't need lit-room-brightness. If you wait for a XM-L, it'll even work with a easy driver. Mechanical fit with heatsink+emitter+lens needs to be considered, but all in all I think "easier" than I expected.
Incidentally I found this sst-90 driver