Instructables
Picture of LED Projector Lamp v.2.0
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For those of you who stumble upon this instructable, a bit of history is mandatory in order to better understand my goals with this LED projector lamp. Therefore I recommend you first read the LED Projector Lamp v.1.0 instructable I posted a while ago. Check back when you’re done for this second part of my adventure.

For this version of the projector lamp I knew I had to find a way to at least double the amount of light on the projection screen. As high-power LED’s are very expensive parts around here (I live in Sibiu, Romania) I wanted to try making my own LED array. I chose the NS6W183T LEDs from Nichia. For those of you who don’t know, Nichia is a Japanese company that produces high quality LEDs and were the first to invent the high power blue and white LEDs back in the 90’s. These LEDs were available around here and the light output was tempting.

This instructable is not yet finished. Also the timeframe on this project is unspecified. I'm publishing its progress because I need other user's opinion on some matters in order to finish it. If you think you have something truly valuable to add to this project, be my guest and share you opinion in comments. I'll try to answer them all.
 
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gerbr10 months ago
Have you seen the construction of the light path in a projector using red blue and green leds? You should try thr same with white leds!
claudiopolis (author)  gerbr10 months ago
Sorry but I wouldn't tackle optics on that level. Using prisms and custom-made reflectors, sure, it will work. But I can't have those, nor do I want to lose the DIY spirit. Imagine how such a step will sound in a future instructable: "Step 4. Make a pentaprism using optical glass with one focusing lens having a focal point of 16mm". That might very well be the end of the instructable, none will follow you beyond that step.
Could you possibly use a light pipe system where you take the individual outputs into separate light pipes and combine them into one? This method might have the added advantage of mounting the LED's in a more dispersed pattern for better cooling efficiency.
claudiopolis (author)  mikeyc.20091 year ago
Yes, it would. But I don't have the tools or the materials to come up with something like that. We're talking about advanced optics here. Stuff that the average Joe will never be able to replicate.
It might not take too much. If you have access to clear acylic rods and cement then you are half way there. You could use a standard torch or gas stove for that matter to heat the rods to shape. You just need to make sure that the joints are properly polished before you glue them. I've used toothpaste or flame to polish acrylic before depending on my needs. I'm thinking that there could be one center rod coming up from the center LED and the others feeding into the sides of that rod. If you have a steel rod the size of your center rod then you could mount it in a drill and use the toothpaste to lap the joint for a perfect joint. This method might not be the most efficient at light transmission but 75% is better than nothing.
gazza1541 year ago
With ref to Jpayton,in car ECUs they transfer similar heat by using thru hole plating under the component ,about 10 holes to copper on the other side.Has been working in the car industry for 10 years and I have used the same idea a few times.If anyone is still interested i will post some pics.
claudiopolis (author)  gazza1541 year ago
I already solved the PCB heat transfer by using a aluminium PCB. So no thru hole system necessary. It would have been impossible, anyway, due to the SMD size of the LEDs and the fact that the LED's backside feature electrical connections so a short-circuit would have been unavoidable. The new aluminium PCB solves the heat transfer but the light output is the same, and that's the real problem.
I am currently looking into a new LED. i have tried many ways to focus the light and it is just not worth the time and headache. I recently found this LED

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=221037245498

Still not sure if im going to buy it yet. i am currently at college with out my projector and i want to do some tests and measurements before i buy it. maybe by quadrupling the lumens it will actually work.

do you think its possible to have too bright of a light source?
jpayton2 years ago
What about drilling holes behind each LED then add some sort of copper plug that will contact the back of the led and push agenst the heat sink. and just load it with thermal paste. that should pull the heat stright from the leds. maybe even a full slit across 3 horizontal leds. that will allow some air around them. still use the copper plugs to contact the back of each LED.
ensastiga2 years ago
I'm working on retrofitting my Epson Powerlite S3 with an HP LED. so far I'm thinking of buying this http://www.kaidomain.com/product/details.S009871
but 200 bucks exceeds my budget, so in the meantime I'll go for this http://www.ebay.com/itm/FREE-SH-1x-100W-Cool-WHITE-LED-Lamp-5500-6000K-Bright-Light-High-Power-KD7-/300645874069?pt=LH_DefaultDomain_0&hash=item45ffe3f995#ht_2846wt_956

Due to the nature of the lamp case of my projector (it comes with a collimator lens) I'm expecting not to have big problems on the light source focal point issue.

My only problem will be to fit the right cooling device on the small space that is left on the lamp compartment.

I'll keep posting my progress
robertcook2 years ago
I agree with epolinda that a single LED plus a reflector is probably the right way to go. For a projector, you need collimated light (where the rays are parallel). Each of your LEDs have wide dispersion and without a reflector (and a lens), a fraction of your light is projected toward your screen. Put another way, a single, dimmer LED will actually project more light in the direction you need it.

Also, single high power LEDs are often packaged with a metal circuit board which will better transmit the heat to your heat sink on the back.

Another thing to consider with LED lighting is the spectrum that is output. It appears that you are using cool white LEDs, which output primarily in blue with a smooth curve between red and green. The problem is if you are filtering this into RGB digital output (is this the case?) then the LED spectrum may give odd or dim results (the spectrum notches may not line up well with the filters.) Worse, the color of LEDs change with heat and current and change over time. This is one reason why lighting with smoother spectra (halogen) is used for digital projection.

Also, I really like epolinda's suggestion about driving the LEDs only when the light is needed. That could help dramatically with heat dissipation and power consumption.

jamwaffles2 years ago
It's such a shame to see a very promising project fail :-( What you have up to now is very good, however! That heatsink is beautiful, I must agree, but did you put a little thermal paste between the PCB and base? It wouldn't help much due to having the PCB material in the heat path, but it'd do something.

I wish you the best of luck for this project. Hopefully you'll fix the issues and come up with a working design. Thank you very much for sharing what you have so far!
I am attempting the same problem. Focusing a square LED. Right now I'm using a 1300mA, 2000 lumen LED chip set. There is plenty of light ( I also made the mistake of looking into it ). I'm not too worried about heat. From my calculations it puts out 23.4 watts. Way lower than the original bulb that the projector used. After some long tests of the unit I have fond that the air exiting the projector from the fan is actually cooler than when the original bulb was being used. Right now I'm just trying to get as much light focused as possible. The hardest part so far was finding the bulb checking circut. I'd like to thank you for both of these instructables. They have helped so much. Hope you can find the time and motivation to keep trying with your own projector.
tvm7772 years ago
Ciao Claudio!
I was searching for more components at ebay yesterday and i found this:
http://www.ebay.com/itm/1-High-Power-50-Watt-White-Led-Light-4000LM-3336-/110786280582?pt=LH_DefaultDomain_0&hash=item19cb607c86

This give you 4000 lumens in one single shot, and i saw some videos on youtube of this thing working, and i can say its just amazing.
I've the same problem as you my hobby budget is limited, much people use USD but in my country my coin its in devaluation.
Anyways, this led its incredible cheap, even shipping its free to ROMANIA :)

check it and write me back :)
claudiopolis (author)  tvm7772 years ago
I know that one. There is a 100W version too. The local reseller told me he won't be importing those anymore because more than half of their sold units burned out in customer's hands, The leds are overdriven and prone to failure in short time. Also the cooling required was insane. And besides, it has the same problem I'm having here; square light source, even wider angle, no way to focus properly...
There are two points I'd like to add to this discussion.

First, if you use one of those high power LEDs, you don't have to make it work at full power. Some of them provide more than 10.000 lumens at full power, but you could drive it with a lower current, getting less light and dissipating less power.

The second point that someone could try is that the LEDs don't have to stay on all the time. If we drive the LEDs using a MOSFET and a small synchronizing circuit, we could keep the LEDs off during the blanking periods, we could reduce the power dissipation to a very lower level.

These are some ideas i have about this issue that I can't not test right now, but I would if I had the time and the means.

Best o luck with your project(or).

Emerson, from Brazil
I saw lanterns made of this, and according to most videos doesnt heat that much(i mean enough to be cooled with a single fan), BUT now i think about, most of proyects are LANTERNS, that mean that doesnt need to be turned on so much time, as a projector does.
I dont know about the lifetime about this, but im sure its long enough, but dont know about the fail on products, well, if fails before its suggested you can always claim refund as its an ebay user protect program, i dont see any necessary buying to locals (most of they win some commission on each sell) since you can buy yourself on internet and without pay shipping and rates.
What's your solution for the square light source?
IMO your tiny light source wont give much LUMENS
claudiopolis (author)  tvm7772 years ago
there are 9 leds. Each puts out 245 lumens. You do the math. I'm trying to focus a square but with no real solution yet. If you read the entire instructable you'll get that.
jetzi19732 years ago
Hmmm i just wonder if you hawe a old flashlight that you can adjust the beam on. If you can try to mount the led in the housing at the right possision so you get the right angle on the beam then you get it to work i think.
The housing on the old flashlights can take quit amount of heat.
carlos66ba2 years ago
This looks very professional and very nice. I have one element of concern: the PCB is not really a good heat conductor and you are placing it between the LEDs and the heat sink. This does not look very good. Here is one possible suggestion: put some "sil-pad" on the heat sink, then glue to it the LEDs, then try to do wired connections between LEDs. This should improve the heat transmission.
you are awesome :) smooth. clean and smart! you are an artist :) good luck :)