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Link to final version


Hi,

I'm new in this forum and new in projector diy so I started by retrofitting an commercial projector Telex P600 with LED's.
The LED are from ebay the 10mm 6-chips 100mA but to be safe I use the LED only to 70mA.
My english is not very good so I apologies if what I wrote sound terrible
I'm electronic engineer so it was no problem to remove the power supply and trick the electronic in believing that the bulb is working.
I used 30 LEDs 5x6 that are specified as 280000 mcd yes 280k mcd and angle of 40 but this give 100 lumen for 3.1V x 100mA 0.31 W and I think that the LED efficients is below 100lumen/w
so I suspect that at least the angle is less than 20. and lumen output about 20lumen/LED.
I will receive next week a Lux-meter hop to now how to use this tool .
The output seems low is possible to watch only with light off and even then is not bright enough.
The original bulb was a UHP 120W 7000lumen an now I hope to have 30led x 20lumen 600lumen so 11x less and the original output was 800 lumen so I expect less than 40 lumen because I use the LED at only 70% .
The space is limited so I don't now how to get more light from the projector maybe you have some idea .
See the attached photo.

And I forgot to mention that the projector cost me 96$ including transportation and tax from ebay the LED was 17$ and some LED drivers and resistors 15$




[color="#FF0000"][/color]

It looks like the light output is nice and even! Also, it looks like the light output is very blue. I think white LEDs tend to turn blue when they're overheating. If the blue tint is actually there (and not just an effect of the camera or something) try driving them with less power, or maybe put a fan on them.

20 lumens per LED is probably about right. Like you said 7000 lumens to 600 lumens is a huge drop! Maybe adding a second row of LEDs would help a little, but by the sound of it you'd be lucky to get 20% of the original output.

Something to consider would be what I call "Super High Power LEDs" like these...
http://www.kaidomain.com/WEBUI/ProductDeta...spx?TranID=3235
http://www.lumenlab.com/forums/index.php?showtopic=24240

Well, being an electrical engineer, obviously the wiring part is easy.

I'd look into getting rid of those 10mm LEDs. They're too large, and you can't get a proper amount of light from them.

This isn't because of hte light being produced, it's because of the ANGLE that it produces the light over. 40 degrees is a pretty wide dispersion. I know that there are LEDs with a 15 degree dispersion (I have a bunch of them) This keeps more of the light directed towards the projection lens, which will result in a brighter projection by virtue of less wasted light.

I suppose that you could try positioning an array of 30 lenses in front of your LEDs in order to more efficiently collect the light from them as well. They don't need to be high quality lenses, but of course the better they are... I'd look for better LEDs to start with, myself.

Thanks for your replays
The LED light is a little blue but the output from the projector is ok just that the camera was on long time exposure an it was completely dark in the room so I don't heave a problem with the blue I will post some photo next week when i will receive the VGA cable I have 3 notebooks and no desktop so no vga .
About the LED , I sow the first one on ebay but it need cooling and lens and I have a limited space to put all this in the projector. The second one 100w with 60lumen/W sound to good to be true only 30x30x1 mm but I will need relay heavy cooling and It will not fit my projector even i use half of that power and the lens aghain (my optics knowledge are very basic).
The 10mm LED have the spec as 0.5W 280kmcd and 3.4V to 3.8V 6-chips so i can use 4x5mm led but the brightest was 55kmcd the max matrix of LED must have 65x65 mm .
For the space with no cooling this was the best option from what I now .The 1w ,3w and 5w led on ebay need cooling and lens.
about the 40 degrees angle is not relay 40 is more like 15 as you can see on one of my posted photos.
and i don't now if the integrator lens that I have in the projector witch help with light uniformiti are not accepting higher angle. see Integrator-lens .
And if i move the LED array closer to the integrator lens you see in the photos I will start to see the LEDs in the projected image but no increase in brightens.
One question :
From my understanding if the projector was originaly 800 ANSI lumen and was able to project up to 8m diagonal I will need 16 time less output 50 ANSI lumen or so to have the same image on 2m diagonal.
I don't need a very bright image since I have the possibility to control the light in the room and the projected image will be from 1.2m up to 2m diagonal using the zoom.
Now i project on plain white wall (not 100% white is a bit gray ) with white paper I don't see to much difference almost no difference from the wall. The best result was to use a aluminum foil that is used by my wife in the kitchen using the mat part of the foil I see 5x impruvment in light but i think is to reflexive so if I use something in the middle I will have 2x improvement in the image brightness.

There are some good screen ideas going on over in the Home Theater section of the forum, particularly the thread about top coats used for low lumen projectors. Nice work!

i think the best way to get a bright image is to use a 35W or 50W Xenon Kit.

Modding a comercial projector with LED's won't work good anyway. But the best way for you would be a single High Power LED as Hirudin posted it.

I received the VGA cable today and I attached some photos but with the light from outside I was able to project only 20" or so.
The colors seems fine for me the menu of the projector as you can see is light blue not white but the withe still have some small amount of blue but this don't bother me since I could ad 1 or 2 red led and solve the problem.
maneee I agree that the xenon will give me more light but I love LEDs ,about the power LEDs there are 2 problems first they need cooling so with limited space I don't think I can fit more than 20W power LED and second they are not so efficient as small LED .
A 20W LED will give me 1000 lumen this is possible with 50 x 10mm LED and will give me the same 1000 lumen without the need for cooling.
I will add more photo after the dark is coming in Canada .

Does your commercial projector have optics and stuff to split the white light into seperate red, green, and blue channels? If so, maybe you could take the projector apart and put similar arrays (to what you have now) in front of the red, green, and blue LCDs?

Yes it have 3LCD for RED GREEN and BLUE but they are about 1.3 inch this should be 3.3cm so about 30x25 mm this is much smaller than 65x65 mm and I will not get the same uniformity of light because I skip the integrator lens.
Is more convenient to work with white LED than to work with 3 separate LED and the colored LED have less power.
I also purchase on ebay another old projector with some new technology this new projector cost me even less only 10$ + 46$ for shipping so total of 56$ an I hope is OK is double the weight almost 12kg .The advantage compare with this that I have is that it uses micro lens array on the LCDs so you have a small lens for each pixel and this should increase efficients by 60% so 16% of the light will be on the projected screen compare to only 11% on this one.
I have made some more photos with the projection now in the dark with about 1.8m diagonal.

I ordered 50 x 10mm LED 100mA from another ebay store Topbright this are 5-chips (this that I have are 6-chips) but I hope are better quality and I will test the output of both wen I will receive the lux-meter also I ordered 10 x 10mm led RED 70kmcd at 20mA hoping to improve the white.
I attached some photos with the proposed led matrix and the current one the new matrix will have 50 LED compare with 30 to the actual one so hope to double the light output close to 1000 lumen or more this is the same as 20w power led but no problem with heat

i think you should use a high power array with Cree Q5 (most efficient led right now on the market) with this 6° (perfect angle) optics:

7 Cluster Optics for CREE
http://www.polymer-optics.co.uk/products%2...ics%20cree.html
download - LED Optic Brochure (Cree) 2007 (1,434 KB)
Part no. 134 and 135

with your space (i guess around 80mm*60mm) you'll get around 25-30 on the array.

you can drive them @ 1W with low power consumption or when you need more brightness up to 3W. cooling would be easily realised by a small watercooling system.

the problem with your LED's is the angle with 40° only a low angle light (<10°) will pass the beamer so you wast 3/4 of your light.

so with 10mm 40° you'll only get 250Lumen and on the screen i guess you'll have about 1-2 Ansi.

with 30*Q5 and 6° optics @350mA each you'll get min.107lumen*30 ~ 3200Lumen and @ 1000mA you'll get min.214lumen*30 ~ 6400 Lumen.


Another point is that you can't compare point lightning like a perfect metal halid lamp with array lightning. for best results you need a very small "light gap" very hard to explain in english for me ... with led's you don't have a light gap.

What's the total lumen your led array will give? I'm also doing tests with this, but I haven't tried it in a projector...

btw, where are u from?

The Q5 have 2cm and the space that I have is 65x65mm so max of 9 Q5 LED (there is more space 80x80mm but the light array is limited to 65x65mm) so for each Q5 I could use 4 x 10mm led that could give me min 20lumen x 4 = 80lumen and if I use a new row of LED I will almost double the light output about 140lumen an I need no cooling .
the spec for the 10mm LED are 40 degree and 280kmcd if I use this in calculation I get 100 lumen but from what I so the angle is less than 40 degree close to 20 degree but I wait for the luxmeter and then I could test the LED and the output from the projector .
An I now that many people here are discussing about the light angle for light source that can pass the LCD but I have some optics before the LCD and I believe that this optics can use bigger angle see integrator lens .
Next week I will get the luxmeter and I could do more test .

You have the same LED? if so you have measured the light output?
the total lumen I estimate to be 20lumen x 30led = 600 lumen not to much and with the new LED array that I wanth to build when I will recive the LED I will have 20lumen x 50led = 1000lumen.

i mean you should make an array like this:

the width of the optics is 13mm

I'm glad you mentioned that integrator lens! I just saw one for the first time a couple days ago, at the time I thought it looked like it might be too complicated to attempt DIY-style, but now I'm thinking it might be something I should look into...

This will be my last cree suggestion...
The Cree LEDs can put out like 130 lumens apiece without producing much heat, I don't think 16 in a 4x4 grid (18 mm apart) would be too much for a 65 mm x 65 mm square... 16 x 130 should give ya more than 2000 lumens. A single 80 mm fan should be able to cool that.

Thank you for posting the photo the q5 that I so was mounted on a hexagonal aluminum base with 2cm diagonal.
Where do you use this array and how is the heat (you need active cooling).
Lucks good, how much is the cost of LED and lens ?

i don't use it a friend used it with his 3.5" beamer but he used 25° optics which is too much for DIY.

you may buy the led's from crazychen's mass order. prices between 3USD and 6USD very cheap !

the optics are from the company polymer optics, don't know exactly where to buy.

for cooling, think about watercooling.

2000 lumen sound good but I don't now if this is real or just spec as I said the spec for the 10mm LED is 100 lumen this is not real an power led have 40-60 lumen /W the 80-100lumen/W is when they are driven by small current like 20-50mA. But I'm open to suggestion . If I'm not happy with the light output from this LED and I will find out more when I will have the Luxmeter to test.

I made some photo last night and maybe you are interested . It seems that the blue is to strong and the red is orange

watercooling is to much and I will prefer not to add new cooler to the projector.
I will be happy if I double the light and If the new projector is 1.5x more efficient + if I manage to get a high gain screen then I will have 2x from LED ,1.5x from projector and 2x from screen this should be 6x the actual image this is OK for me.

The Cree specs are probably pretty close, those 5 mm / 10 mm LED suppliers lie left and right, I think the specs of the high power LEDs are more accurate.

Just to be clear, the LEDs in the photo above (here) are actually Luxeon Rebels (another high quality, high power LED).

In my attached photo Crees = green arrows, the rest are Seoul LEDs (another big LED manufacturer)...

Here are some of them LEDs lit up, check out how the circuit board is glowing for an idea of how bright they really are. Also, check out the color difference! The Crees in this shot (right side) are definitely not putting out "too much" blue... These are "WH" tint crees by the way.

I so this photo in some other place the power led are to big for 65x65mm and I could not use more than 4 up to 9 depending on type and 4x10mm led have 1W real or 2W from the spec
this I use now
10mmLED6Chips
this I need to come
10mmLED5Chips

And the last LED with 5 Chips lucks more white in the photo I will see.

Sorry to be so happy with my 10mm led 4x10mm is 1W power with 80lumen and need 20x20mm with no cooling. and I have the posibility to double this by adding a new row on only 20x20mm and the cost for 4x10mm 1W is 2$ no optics needed and no cooling

Maarten I so the problem you have with 10mm LED different voltage drop on LED . What type of LED do you use . The one that I use are for 80mA in a test of 30 LEDs the voltage was from 3.04 to 3.08V average was 3.05V

I use 10 mm 15degree 20 lumen leds btw why don't you put your leds as close as possible to eachother... u have spaces... that's waste of extra light! The Vf problem is already solved!

grtz Keires

That integrator looks very interesting indeed, does somebody know where you can get it?

The 15 degree 20 lumen sound great were did you buy this ?
The output for this should be 380000mcd according to this calculator mcd-to-lumen

I don’t think an integrator pair will be much use to our DIY projectors unless we have a triplet equal to or bigger than the LCD.

DJ

Phew, that's a load off, thanks!

I don't think that site is correct... If there are more people interested in the 10mm 20lm 15 degrees leds, I will start a group buy, because the min order is 2000

Grtz Maarten

Hmm I have a triplet bigger than the LCD, maybe I should try it... just to see what the result is

BTW why does it have to be bigger or equal?

what is the spec of this led ? from where do you buy? and what price. I will maybe interested in 100.

I'm not to big expert in optics so don't take my answer as good but I think the integrator lens need to be as big as the lcd not the triplet The integrator lens is used to better illuminate the LCD and replace the first fresnel lens.

I oped the projector last night I have a big problem with the green LCD that I moved from is place first time when I opened the projector is only 3 point glued and I have a shift of 2 pixel for green but I was not able to make the fine tuning because I could not display on the screen when is open I need to remove some electronics in order to access the LCDs what I see is a white scren from my LEDs and some green on the edges of the screen . I also seen this after the integrator lens is a polarization changer.

What will be the total of your lumen? Because I think I have a better idea, greetings Keires...

I don't now I will be happy with as many lumen as possible but in a limited space of 65x65 this mean max of 6x6 10mm led + stage 2 5x5 so max 36+25=61led x 20 lumen ~ 1200lumen for the light and with 10% out will be 120lumen output now I have 30LED with 20lumen or less I use them at only 70mA(100mA-max) so about 400lumen but I will be sure of this when I will receive the luxmeter
so my target is more than 100lumen output from the projector.
What will be your idea ?

I don't think that idea will work, and here's why:
Click to view attachment
As you can see, in the next iteration of the changer, you instead of getting 2 "S" polar waves, you instead get 2 "P" polar waves. That is, unless you can be precuse enough with the light that it only hits every second iteration, which is a level of precision that I don't think I'd want to try with DIY optics.

The following requires something that I don't know is possible, but it's the only way that I can see this working. This requires a polariser that will pass light in a given orientation in ONE direction, but reflect it on the other direction.

Or maybe someone can suggest an improvement here...
Click to view attachment

You are right I don't think that the polarization of light can be used in DIY but the integrator lens should work
this nice site explain all this technology used in 3LCD projector an they have nice animation also 3LCD-projector

Integrator

There’s one part they haven’t included in their diagram. There should be reflective strips limiting what sections of the recycler are receiving light.http://www.lumenlab.com/forums/index.php?s...st&p=254414


Looks like you’ve caught the polarization bug as well


DJ

Very interesting Dazzle, ty for the link, but due to no time I'm not going to read the whole topic, I looked to the pictures and I concluded what you are up to I hope it works m8!

@electrodacus, does the angle of your light source has to be as small as possible? Will it also work for example with 1 light source and an angle of 8degrees, (probably it will, because that's how they do it in standard projectors )

Grtz Keires

I think it will work but I'm not sure . I have tested with one LED 5mm with 25 degree and if I was very close to the integrator lens I could see the led on the image but if I was back 40mm then the light output was perfect as good as is now withe 30 LED array. The original lamp was a UHP 120W and used a reflector. Do you now a power led that delivers more than 1000 lumen

I did some test today with a 11W florescent bulb and 60W incandescent without a reflector and the result is worse than a 5mm led .
And I measured the angle of the Led array and is 17 degrees far from 40 that was specified and I hope that the 280kmcd are much closer to spec than angle .
I still wait the luxmeter.

This is a photo that I have taken one hour ago. It seems that my photo camera Kodak P880 see more blue than actual image is hard to make a photo that lucks like actual projection. This is close but not so vibrant colors as real projection the projection screen was only 55cm and lucks better than my laptop LCD.

I received my luxmeter in this morning delivered buy Canada Post it was a long way from Hong Kong but only cost me 27$.
Now the bad story I did some measurements this morning and the results ...... I was expecting bad but not so bad
The output from LED array was 1480 lux in the middle of the spot at 1m distance and at 3m I had a 1m x 0.8m spot on the wall and the ridings was from 145 in the middle to 70 on the edge.
with only one LED at 70mA it was 70lux from 1m so max at 100mA will be 100lux at 1m this mean 100cd and not 280cd as specified.
But much worse is the output from the projector I had a 58cm x 43cm projected image and the riding before with the light in the room was 32lux and with the projector on I had 38lux so 6lux on 1/4sqm this mean 1.5 lumen I hope I do something wrong.
I will like your input on this since I don't now what to do next. I don't need a big image something between 1 and 2sqm but the result are relay bad and I was expecting 90% light loss but then I will have 10% on screen this mean 10% of 80lumen from LEDs 8 lumen but not 1.5
I will repeat the test in the dark maybe I will have the same output then it will be about 9 lumen which is better.

Now I have done a color test I compare with my LCD 14inch HP notebook.
The HP LCD 50% RED | 100% GREEN | 73% BLUE
LED projector1 20% RED | 100% GREEN | 77% BLUE
LED projector2 30% RED | 100% GREEN | 77% BLUE

So I need more red in my image as I new already.

If fun to play with the Lux-meter.

i was sure that your output would be between 1 and 5 Lumen.

You really should use a high power led panel or gave up led and use xenon

5 lumen sound great now but I don't want to use xenon I will stay with LED. Unfortunately I already order 50x 10mm led hope to be at least double in power so I will get 5 or 6 lumen out of the projector but still not enough my target is min 25 lumen as the Mitsubishi PK20 .
I think next I will test high power led if you have some suggestion not more than 20w in total currently I have 7W and I will have 15W with the next array but I don't want special cooling.
Strange that from my calculation this 7W led array put out only 100 lumen and this is less than 15 lumen/W and I expect 40-80 lumen/W
Also even with 100lumen the output should be 10lumen not 1.5lumen

Now with no light in the room I repeated the measurements and the result is 1 Lumen the read was 2lux for 0.5sqm screen.
But I still don't understand way the input is 100 lumen and the output only 1% I was expecting more than 10% (originally they had a 120w UHP with 7000 lumen and output was 800 lumen).
As I already mentioned the LED have a angle of 17 degree. and only max 5 lumen for 100mA this is less then my 20 lumen expectation and way less than 100lumen they spec for this LED on ebay. Now I really don't now what is wrong.
HELP!!!!!!!!!!!!

You are wasting allot of the LED’s light because of its beam angle. The projector is expecting slightly converging light, the LEDs are supplying <17°. They may even be 34° total beam angle?

DJ

Edit:
You could try using a lens in front of your LEDs. This may be enough to converge the rays down to the LCDs

Edit2:
Second thoughts, it may not.