I was just wondering if anyone has used any light sources other than high pressure sodium and metal halide bulbs. I have used halogen but it gets way too hot for my liking.

halogns get hot and they don't produce as much light or as high quality light compared to MH. Some people have experimented with LEDs, but the current components available at a reasonable price don't produce enough light. LEDs conform to Moore's Law though, and the brightness should double every 18 months I can see 1080p LED powered DIY projectors being made inexpensively in the near future.

But currently the LED setup will give you 50-75 lumens, and time taking wiring. So for most people its off the radar screen...

Im new to this site so i dont know anything!!! (but Im trying to read everything,,,gonna take a while) Can LEDS be used in combos? or does the light need a single point to project evenly....In my searches I found this LED and it got me wondering,,,,,with heat and noise being 2 of the things these (might someday) cure..

http://www.luxeonstar.com/item.php?id=1811...o=LXK2-PW14-U00


this single LED is 130 lumens, not enough unless you could stuff a bunch more in somehow (if light can be added up that way) 100000 hours would be sweet....

newbie dave (flyer)

Suppose you had a board of 40 of those, you'd have 5,200 lumens being output, and only a fraction would make its way to the panel, and with 40 that would be 200$...The technology is advancing, but its not quite there yet

Hi Lumen gang. First post.

I was pricing white LEDS last night for just this application.
I priced 5mm white LEDs at around $180 for 196 of them.

It would be a 14 x 14 grid.
I have allot of experience with LEDs and I am sure I could get this to work.

The benefits in my opinion greatly out weigh the cost.
1) Massive reduction of heat. These projector bulbs seem to be quite a fire hazard.
2) With a $3 dollar IC you could multiplex the banks and reduce amps and control brightness.
3) Each LED could easily be replaced via a standard header.
4) Reduce AC voltage inside of the box.


My question is that if I build it, would it produce enough light for the projector.
I was not aware that lumen's could be added in that way.

If you have a perfectly dark room, go for it, although any ambient light is going to wash out your projection. Which will probably be between 25-75 lumens.

A LED solution would be great!
I have been thinking about his too. Would the color temperature of this light be good?

I think with a LED array you will have to get rid of the collimator fresnel and reuse some of the backlighting of the LCD. Getting the light 'parallell' would be a problem i think.
You can even 'flash' the LEDs and be able to control the amount of light, but i suspect running them continously would be needed to produce enough light.
The costs would be the same or cheaper if you compare it to a lamp,reflector,collimator fresnel,mogul and ballast. It will save some space too and the heat will be a lot less.

I am still in the studying and designing process so i can only 'imagine' how it would work.
Unfortunately no practical tests for me for a while. And not too much knowledge of optics and light either.
Still reading then threads about optics and lights.

Another option would be to enhance the backlighting with a lot of extra tubes. I remember opening a defective laptop monitor to discover there was only 1! I expected there would be more. This screen was already bright and even if you looked good readable with direct sunlight. What would that screen look like with 10 or 20 tubes! I know now i should not have sold it for a pittance.
No knowledge about desktop monitors only the ones that are documented when stripped on this site.
Maybe enhancing the backlight would be enough when the PJ is used in total darkness and/or until a certain projected size.

Did someone ever test a LCD with its original backlight?

I've added some LED information to the FAQ/Before you start topic pinned here. Also lighting other than MH is discussed.

I don't have the time now but I will investigate this concept and report back here shortly.

A couple of other things here. HPS is no good. The S400DD is NOT an HPS lamp, but a MH lamp designed to run on an HPS ballast.

Halogen lamps, such as those which run in OHPs are also viable.

I've come up with an alternative that, believe it or not, works . Right now I have 6 bulbs (26W CFLs - 1700 lumens each) in my rough projector box and am able to get the beginnings of a nice image. I originally started with 1 bulb and kept adding a bulb - the image kept getting nicer. Now its not clear enough yet to watch a movie (mainly because I am projecting with a page magnifier instead of a projection lens) but I will continue to test this set up by adding more bulbs. I know we are suppose to use a point source but this seems to work anyways. If I had a projection lens I think the image would be quite suitable for watching a movie.

Did a little research tonight.
Listed below in no order. I'm just placing it in this thread as I go.

First off, why are there no dates on web pages.
Useless for research.

For those of you that want some background look at the advantages and disadvantages of LEDs.
No idea when these pages were written but they are short.
Advantages
http://lightingdesignlab.com/articles/LED_.../led_advant.htm
Disadvantages
http://lightingdesignlab.com/articles/LED_.../led_disadv.htm

For this example I am using this LED.
http://www.superbrightleds.com/specs/W18030.htm

I don't know the color temp of this LED but it will work to do some math.

The unit of measure commonly used to describe LED intensity is the millicandela (mcd), 1000 millicandela equals 1 candela.
The unit of measure commonly used for most other light sources is the Lumen.
Lumens are units of Luminous Flux and they measure how much light actually falls on a surface.
The Luminous Flux (lumens) from a light source is equal to the Luminous Intensity (candelas) multiplied by the solid angle over which the light is emitted, taking into account the varying intensities in different directions.

Fortunately we have this:
http://led.linear1.org/lumen.wiz , Luminous Intensity to Lumen Converter

This LED.
Luminous Intensity : 18000 mcd
Beam Angle (degrees) : 30
Equates to 3.854 lumens.

Add 195 more LEDs and you get 755.3 Lumens.

About 2000 short of where I want to be.

As for color temperature I did see a wide range of numbers.
From 9000K up to 100000k.


Conclusions for tonight.
I still have not found a formula that explains light intensity increase as more LEDs are added.
700 Lumens are usable, but only in a dark room.
Seems to me the LED array would have to be facing away from the LCD and reflected back via mirrors for a good flow of light.
If using LEDs the goal is to get all that light (no point source) to its starting point (Fresnel lens) then the optics can take over.
During my research I came across allot of low voltage (low heat) lighting alternatives that definitely should be looked into.
Might need a slight diffuser on front of the LEDs.
I need a thousand LEDs!

More to come as I go.

Good LED sites.
http://www.gizmology.net/LEDs.htm
http://www.ecse.rpi.edu/schubert/Light-Emi...Diodes-dot-org/
http://www.superbrightleds.com/led_info.htm

Hey punisher, just a tip here. Since CFL's aren't point source, don't treat them like point source. What works really well is if you build a reflecting lightbox out of acrylic mirror to put the CFL bulbs into. Make all four sides and the bottom out of the mirror. The open end is where you put the LCD. The whole point is to give the light only one way to go out......through the LCD. Also, the bulbs only need to be an inch or two away from the LCD, and you don't need a fresnel before the LCD either. The light is amazingly even because of the mirrors.
One thing, the box will get a little hot after a while, so adding a fan to your lightbox (just a small one) is a good idea to cool it down some. You will be totally blown away by how bright your projection will be with just the bulbs you have now.

I got my acrylic mirror at US Plastics Acrylic Mirror Link but it can be sometimes found in the trash at department stores when they change out those tacky little mirrored displays that they use for perfume and stuff.

I'm using a 65 watt full spectrum CFL, it is huge, I wish I had thought of using more smaller ones instead, my projector could be even shorter.

T.

the_punisher & tgreenwood,

It would be very interesting to see what you both have some up with in this department. It has been debated about how well a non-point source light works in comparison to the MH lamps commonly used. Things that were of concern included 1) non point light source so, no collimating fresnel, but also no collimated light... thought to be bad 2) the lumen/watt output of CFL's is much lower than MH.

If you are able to take some photos of your setups and post them, that would be great. If your able to quantify the lumen output at the screen for these designs (using a lux meter), that would be even better as it would provide a true reference point for comparison.

Interested to see exactly what you've got there.

cheers,
gs

What I would be concerned about is 'hot spotting' -- there will obviously be some 'collimated' light, which comes straight from the lamps throught he LCD, it's all the off angle stuff that concerns me.

Where the light goes straight from the lamps, the image is very likely to be brighter. Keeping a diffusing layer (Like the standard backlight) may help this.

I would also be concerned about all the 'stray' light forward of the LCD, it seems to me that this would be likely to reflect around and cause some loss of contrast in the resulting projection. It should, however, be controllable.

Certainly it's worth examination.

My instinct though is that it's working better with the page magnifier (larger area) than it will with a projection triplet. By all means, though, let us know how the experiment works out.

Damn that 65W must be really huge - I saw a 42W and that was very big. How do you have your bulb oriented? What wattage incandescent is it equivalent to? Since I'm still testing this set up I have lined a wooden box with aluminum foil to reflect some light. For the final thing I think I might do what you suggested and use the acrylic mirror for the light box.

With the 6 bulbs a computer fan running off of 9v is keeping the box nice and cool and its not too loud either

GadgetSmith I will try to take a picture and post it later tonight.

I got my 65 watt at R.E Williams Contractor, Inc and here are the specs....

Full Spectrum 55 Watt Compact Fluorescent Light Bulb (it is a typo on the web page, it is really 65 watt)
This full spectrum light bulb will replace a 300 watt incandescent or halogen bulb.
Color Rendering Index: 91
Color Temperature: 5500 Kelvin
The dimensions of this bulb are 4" x 8 1/2".
Light output: 4100 lumens
Average Bulb Life: 8,000 hrs
Warranty: One Year

I figured that the CRI and Color Temp were just right.
I have it in the mirror box pointing at the lcd (using a Psone 5 inch right now) with the light socket at the rear of the box. My projector is real ghetto style, I have the acrylic mirror box taped together around the outside with masking tape, and took apart an old lamp for the bulb socket.
I was using an 18 inch focal length opaque projector lens (no fresnels at all) but the throw was just too long and the image on the screen not big enough, so I took the projector apart. I sold my opaque projector lens and I'm going to try a crt projection lens and a copy lens I got from surplusshed.

I'll put it back together, take one picture with each lens, and we will see the difference.

Check out 3M's light tunnel, used for projection. I know that mine is not exactly the same, but I think that the theory is sound. Vikuiti™ Hollow Light Tunnel .

Tgreenwood

By the way, I have tried projecting with just the backlight on a Psone lcd with a CRT projection lens. It was pretty dim, but it was sharp and even as hell. Really surprised me.

Gonna have to wait a bit longer for some pics - need to recharge my camera batteries. I'm also gonna order the S15 lens kit now - I really need a projection lens because the page magnifier doesn't focus the entire image properly. One side makes the centre very clear but everything else blurry and the other makes the entire image visible but not perfectly clear.

Ah... I missed that you were using a fresnel (page magnifier) for the projection lens. I'll agree with Supraguy... the page magnifier is capturing more light due to it's size. Once you add a projection triplet I think you'll find a large decrease in the amount of light at the screen... BUT, you'll find the image is much more in focus and pleasing to watch. It will be interesting to see what you come up with.

cheers,
gs

What about achieving an alternate white light from LEDs by combining red, green and blue LEDs. Would this result in a different color temperature and reduced brightness efficiency from a combined color LED array?

I've thought of that... There are a few problems.

1. It's really hard to get an exact match in intensity for the RGB to get a decent 'white'

2. 'White' LEDs are actually blue LEDs with something added to fill in a yellow. So it turns out that there isn't a signifigant cost savings in using the combination.

Basically, the white LEDs end up being a better option, as far as LEDs go. If you could use tiny LEDs that match the sub-pixels, that would work better, but would be prohibitively expensive, and complicated to build. There would need to be FAR too many individual pieces to practically assemble.

I removed the fresnel that was before the LCD and moved the bulbs about 2 inches closer to the panel. I tried putting them as close as possible to the panel but it resulted in hot spots. After doing this the sides of the image are not blurry like before. Gonna hold off on ordering the lens for now. I want to see how the image looks when I increase the number of bulbs. If it gets better I might not even get a projection lens lol.

Current Set Up:
-------------------
Six 26W CFLS --->LCD--->Page Magnifier

Hello everybody, I'm new here and this is my first post.. been doing a lot of reading and learning and this is all very inspireing stuff.

Punisher,

Can you post some pics of this project? esp the light array. I'm considering using CFL's (2 - 40w , 2600 lumens each) as I looking for a very inexpensive alternative to buying a pricey ballast for a Metal Halide lamp.

keep up the great work,

Dirk

Sure I'll post some pics on the weekend - tomorrow I'm going to pick up some more stuff for it and I'll take some pics once the array is filled (right now I only have 6 sockets installed - gonna have more). I have attached a sketch of how it looks - the bulbs are mounted on the back panel of the enclosure and the tips are facing the LCD. I didn't use a fresnel before the LCD so I will probably end up filling the whole array so the entire screen is bright enough. I've been trying to take pictures of a projected image but my digital camera can't pick up a decent picture - any tips?
Click to view attachment

This idea may have come of age as there are ever more powerful CFL's being made. I've never seen until now a 200W CFL. Whether you use one or many CFL's the light engine mechanics should be the same.

The best take on the idea of the diffuse light engine was theorized by forum member Mark.(really smart fellow)

I think (following Mark's lead) that a bright flat white box as shallow as possible might be better than mirrors in reducing hotspots.

Check the specs on this lamp at http://www.1000bulbs.com/
Catalog Code: FC200/88993
$110.63 Each
Base Type Mogul Screw-In Case Quantity 12 Over All Length 15 in. Over All Width 4 3/4 in. Warranty 12 Months Shape U-Tube Life Hours (Avg) 10,000 hrs. Voltage 120 Lumens (Inital) 13000 Wattage 150 Color Temperature (Kelvin) 6400 Incandescent Equivalent (Approx) 850
Additional Information Limited Quantities Available.

World-Class Full Spectrum Designer Phosphors Guarantees High Lumen Maintenance And Excellent Color Rendering <li>200 Watt <li>Full Spectrum High Definition <li>Approximate Incandescent Equivalent: 850 Watts <li>Save 550 Watts in Energy <li>Mogul Base <li>Color or Hue = Stark White, 6400 Kelvin <li>12 Month Warranty

Finally got some pics with my camera.

What the camera picked up:
---------------------------------
Click to view attachment

What it really looks like (I used Photoshop to increase the brightness to what it looks like on the wall):
---------------------------------------------------------------------------------------------------------------------
Click to view attachment


Like everyone says, it actually looks better in person.

LOL yes I still use windows 98 (on my really old laptop)
Only the centre of the projection is bright because I have the 6 bulbs clustered at the centre of the screen.
I'll post some pics after I add more bulbs and seal up all of my light leaks.

Unfortunately there is a lot of light escaping from the fan hole. Anyone know how to address this?

anyone thought of using xeon or xenon lamps foung a good site with info on projection light engines

projection lamps

I am still researching the possibility of using LEDs, but I keep finding myself leaning toward using a "white wall" the same size as the LCD. Keep in mind my goal here is to greatly reduce the heat (fire hazard) from the light source.

Two questions.
If the light source is the same size as the LCD can I remove the first Fresnel and thus reduce the length of the projector by 8" or so?

Anyone know the heat output of this kind of bulb?
http://www.1000bulbs.com/product.php?product=1248

Thanks..

yes. likely if you use an LED array, you would want to remove the collimating fresnel.

that link is to a basic incandscent lamp with a special outer globe coating to give a less "yellow" light. that is all find and good, but for 150 watts of power, it generate only 1120 lumens... compare that to a 150W metal halide lamp that generates 10,500 lumens ! The MH lamp is giving ~10x more lumens for the same amount of power... therefore the heat/lumens is MUCH higher for an incandescent lamp than a MH lamp.

cheers,
gs

Thank you. I was not sure. Seemed logical though.




1500 watts for 10,500 lumens!!

Seems the only way to use current low heat technology is to create a more light efficient projector as well.

I'm not giving up yet.

MH is going to be the best technology for DIY for the near future. LEDs need a few more years before they are ready, others aren't bright enough or hav ethe wrong color.

The color temp of the bulbs I'm using is 2700K soft white. The colors in the projected image of a dvd look exactly the same as the colors when I watch the dvd on tv. Now I think I could have used the HPS white bulb I was looking at before which had a color temp of 2700K....but then again I don't want to spend $170+ on a ballast!

Some people like the extra yellow/red of lower color temps, others really want the crisp whites (people can look a little lifeleess) of 7000k. Its a personal preference thing. What wattage was the HPS ballast S51 is the standard 400W HPS and they can be gotten for $50-60.

I was looking at the 400W HPS - I saw the ballast for around $170 (prewired) at a local store (Toronto and its not even electronic). If I can find it cheaper I may get it later - My friend is checking somewhere else for me where it's suppose to be around $100 (not prewired). I still want to do some more trials with the CFLs 1st. The 400W HPS bulb costs only $13 which is appealing also. I Just need a cheaper ballast.

I'd just google the ballast.... less than 60$ generally(www.hidirect.com is where I've gotten ballasts before) .... but I will say that here too, the local lighting store wants 145$ for the exact same ballast I can get online for less than half(delivered)... even if you have to pay some kind of import tax into canada I can't imagine it being that much more....

Just ordered the lens kit - I'll continue experimenting with CFLs after I get it

Darn. Wish I had spotted this thread earlier. The best way I know of to use CFLs is similar
to what you're doing but with the addition of reflectors to direct the sideways light forward.

26 watt lamps here along with R-30 reflectors.
http://www.fullspectrumsolutions.com/compa...cent_32_ctg.htm

Although the page doesn't state the 26 watt lamps will fit into the reflector, they will.
If you get these, don't push directly on the fluorescent tube, instead slide the lamp into
the reflector and pull on the screw base until the mounting tabs grip.

I believe the reflectors sold here are lamp specific, they may or may not fit CFLs from other
manufacturers.

Everyone has talked about CFL and their lack of directionality. what about using
a trumpet top CFL like this Trumpet Top Light and some metal enclosure to reflect the sides when looking at this bulb head on it
basically becomes a 3.5" point light. Now combining 4 of these in a square or diamond pattern inside
the enclosure. wouldnt that give you a great directionality and effective lumen output of approx.
12000 lumens give or take based on an educated guess of approx 600 lumens loss on each for lack of true
directionality?

This is the 1st time I've seen a CFL like that!

They are primarily used for photography from what i've seen. i use these at work for photographing glass, lead crystal , etc. actually they pretty much work for anything they make they colors stand out quite well.

Also these bulbs are not your typical CFL that you can touch. they get quite warm when burning for extended times. so minimal cooling would be required still. I know locally walmart sells one very similar for $10 that actually has better light output

Allright i did a quick test with one inside a tracklight can. i shined it through both fresnels and the LCD with ag still on it. it was held 10 inches approx from the light and produced a faint but visible box from the inside of the frame at 10 feet. Mind you this was a very crude test done just holding the lcd/fresnels so there was major light leakage but. I can assume an array of 6 in a standard 15" pj would probably project a more than visible image on screen at 8 or so feet . even with ambient light

I was going to start a PLOG for my projector but I can't start a new thread in the PLOG section :angry:

Another LED thread.

http://www.bigscreenforums.com/forum_topic.cfm?which=1263

While I was bored the other day I decided to try some more stuff with the page magnifier projecting the image. I took a piece of cardboard big enough to cover it and then I cut a hole in the center. After enlarging the hole a few times the image got much clearer (than the image was with the page magnifier and no cardboard cover) with the exception of two blurry spots. I am going to try and get rid of those later today. I am going to use the lens kit from LL in my build but I was just trying this while I am waiting for it to arrive. If this build goes successful I may try making a projector with a LCD smaller than 15" and using a cut page magnifier.

I remember reading somewhere on the net that using metal halide bulbs in your home voids your fire insurance. True or false?

Nevermind - another person posted in the forums that you really can void your insurance using HID lighting in your house.

That could be a problem for any projector, since most commercial projectors use HID lamps, they're just ones with very short lamp arcs (Hence the low lifespan and high cost.)

Just as an update:
---------------------
I changed the light array set up so that the sides of the bulbs are facing the LCD instead of the tips. I also lined the lighting area with aluminum tape. The image is significantly brighter this way and hot spots are not visible like before.

Hi Punisher, I don't know how far you came with your projector using the CFL, and if it has worked do you mind posting some pics. Anyway I too will try to build a pj using CFLs. So far I have 2 x 48 watt bulbs at around 4000 lumens each. I'll try to line the box with mirrors so that the light is reflected towards the lcd.Hopefully if I design it right I wouldn't have to use more bulbs.