LED PJ Easy Design

this is 8.4LED Board
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Nice! Do you have any measurements on how much light that board emits?

Single LED is 18000MCD-20000MCD.

If ues 8.4 will is better.
But I havn't 8.4 PJ.Than I'm not measurements light.

with 10.6 PJ

10.6 PJ with 250W Lamp

If you want more Info.
You can ask johnzo1995.
He have some 8.4 led baord.

I have 5MM LED Board for 10.6 PJ

what's the advantage of using LED's over the halide bulbs?

150W LAMP is 120 lux on 75 inch (10.6 lcd)

led is 35-50 lux on 75 inch (10.6 lcd)

Click to view attachmentClick to view attachment

i was thinking along the lines of, what are the pros and cons of using LEDs for any projector.

LED's are low in power consumption, low in heat output, and are very stable light sources. They don't produce the same EM interference as an MH ballast does, and those are some obvious advantages.

The boards shown above use "good" output LED's, I've built myself a small board for a 10.6 that is still in progress (waiting on parts, I want to test something before I invest in more LED's) but that uses high output LED's. Instead of 18-20 lumens total output per LED I have 110-130, and 50% of that within 6 degrees of straight (meaning almost 50% of it hits my triplet). I think I could get away with a single 3" fan, but I will likely cross ventilate the front and rear using a pair of fans to keep the entire box cooled.

I want to see this...

Give me a week. I want to get output pics before I really start saying its a great idea. I have my last final for the summer on Friday and get my Triplet this week.

are there any tutorials on making an LED projector? like how there's a tutorial here, except the one here uses halide bulbs.

just pick up a few of these (siemens ostar led) , they are 1 mm wide but put out 1,000 lumens
they last for avg. 50,000 hrs .. so if you use your pj 8 hrs a day .. they will last you 18 years

10 of these is only 10mm wide but will put out 10,000 lumens ..

After passing through the lcd only 30% of the light should be lost through the lenses, unless you are accounting for light beyong the acceptable half angles.

How much did these cost you. Could you post a link where you got these?

one thing i read when i googled them is that 1 cost a guy $65... thats a bit much imo. Cool though.

I also would be interested to know where you got them.

That would make a very strong DIY lamp replacement for a DLP projector.

i dont have them .. i said get some lol

im not sure that they are available to the public yet .. although it appears promising this quater
just google siemens ostar led and keep checking is all i can say

it makes me smile to know that technology is going to make it possible now to make pj's that will be super bright, low power use and last forever ..

http://sunpu.manufacturer.globalsources.co...h-power-LED.htm

these led's are available although you would have to check price with them .. they are 40-50 lumenus flux each

so do the math.. thats pretty powerfull led.

Check this out: http://www.enfis.com/news/press_releases16.htm

i've been thinking of building one myself.
led board for 15inch lcd about 2500 led's
price led's about 180 dollars. (13000mcd 20-25 degrees angle) or should i go for more mcd like 20000 mcd for 255 euro's also 20-25 degree

should i do it or not

You know, the problem I have with those small leds is heat dissipation. Maybe I'm wrong but I simply don't see how they can get the output of the high power leds with no real efficient way to dissipate all that heat.

Interesting, this isn't exactly what I was thinking when I considered LED based light sources. I was assuming each LED would need to be focused, I wanted to place one LED at the focal point behind each element of a compound lens. It seems to me that brute forcing thousands of LEDs wastes much light off-axis. I did some quick investigation into this and was not encouraged by what I found. Wikipedia says LEDs are at 100 lumen per watt and that 1 watt LEDs are commercially available. I found a nice 25 count compound lens in a size suitable for 7" panels. That's 2,500 lumen collimated (yes, that is assuming 100% collimation, but won't focused LEDs come close to that?).

Compare that to a 250W MH generating 100 lumen per watt = 25,000 lumen, but then figure even with a reflector you only get 20% collimated = 5,000 lumen collimated.

The 25 LEDs total 25 watts and generate half the collimated light of the MH. That's not as bad as I was thinking. If we could get a 50 element compound lens we might stand a chance of matching a 250W MH using 50W worth of LEDs. I have some ideas I might toy with, specifically I could tile several small compounds...

Your thoughts?

You are right about the half angle being the most important parameter. The theory is there, but no one has been able to put into practice an led light engine that gets more than 25 or so lumens. The most recent attampt was myself. I put together a high power led engine using all the logic I could muster. My lumens BEFORE the lcd was inserted was less than 250 lumens. that means about 15-25 lumens after I insert the lcd.

That should increase if you use a very wide triplet, but by how much. We really need about 2,000 lumens or more before the lcd is inserted.

It seems to me that to get it done right we really need to have that light nearly perfectly collimated. The lowest half-angle lenses ouit there are 5 degree lenses. That's what I used and they just did not work. See "RGB thread" in this section.

If you decide to go that route good luck. I would just say that it'll cost about $150-$200 and probably will not work. So, it's a gamble.

Any one using led driver circuitry, or are you trying to run the LED's with raw DC? I see you are trying to use resistors, and these just waste power here is a good site for the extreme expenrimenter.

I'm going to try to build a LED backlight kit that puts out some real lumens that is efficent, however I don't know how fesable this is.

1) Proper driving of LED's you can vary the brightness of the leds with proper circuitry, and it's cheap just need to build a kit.. Here is the LED driver I'm thinking about the circuit's simple, and alot of your experiments require high current. I was looking at this driver.

http://www.maxim-ic.com/quick_view2.cfm/qv_pk/5266

2) Led's aren't point lights, and they aren't columnating either. This really beffudles the optics in the projector designs you have here. I see that people are trying to use the light directly this doesn't work either.

3) Heat management. Yes leds do create heat especially high powered leds, there needs to be a cooling arrangment. If there is none then the LED's will last no longer than a MH, or any other bulb. Remeber the whole idea with the led, is long life. In an array you can loose a few leds, but loose to many then there will be unacceptable hot spoting of the image.