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Replacing lamps for LEDs

#1 User is offline   kelvinmead 

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Posted 25 September 2012 - 11:04 PM

So... Lamps for projectors are expensive, and leds are cheap...

Using the housing for an old lamp, and I use an 8x8 grid of 5050 SMd brilliant white 1watt LEDs with relevant heatsink I reckon I can produce around 5000 lumens without meltdown...

Adapt the old mirror and add a converter for the power and dink! Led conversion...

Now I've been thinking this for the past half hour, which is about half as long as I've owned a projector...

Am I missing something obvious, or is this a viable project?

#2 User is offline   WiLL 

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Posted 26 September 2012 - 07:41 AM

I am by no means an expert on optics but would you need some form of primary lens to convert the multiple point sources of a LED grid to a single point source to avoid ghosting? I could, it's true, be gibbering like an idiot though.
Basically, I plug stuff in.

#3 User is offline   gyro_gearloose 

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Posted 26 September 2012 - 09:01 AM

You'd be better off with one of the Bridgelux LEDs. They'll go to 9000 Lumens for about 55 from Farnell, but thats for a cool white LED. You might be better off with a 7500 Lumen neutral white LED as cool white LEDs tend to be much bluer than the discharge lamp you are replacing.

As for the optics, most modern projectors have extremely sophisticated lens systems which can cope with minor lamp mis-alignments. Otherwise the end user would have to manually align the lamp in order to avoid hotspots in the projected image, much like you have to do when you change the lamp on a 35mm projector.

#4 User is offline   kelvinmead 

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Posted 26 September 2012 - 10:13 AM

yeah, I did some searching last night and I didnt even know the large leds existed.

the ones I was looking at were around 35 for 50w 3-5000 lumen, and around 50-60 for 100w 6-8000 lumen, the only holdback being the size of the heatsink required...

these leds emit less like 50 leds stuck together, and more like a single output, so ghosting would be less of an issue, but a specific focusing lens may be useful.

all I need now is an old lamp to do some testing on, or to purchase one, to retrofit... so if anyones got any old lamps for an mitsubishi xd206u!

highly unlikely as people would just discard the old lamps! :)

I'm assuming that people have done this kind of thing before?

#5 User is offline   timsabre 

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Posted 26 September 2012 - 10:23 AM

I think you may find that 8000 lumens is not bright enough. The 200W lamp fitted in that projector will output at least double that.

This post has been edited by timsabre: 26 September 2012 - 10:24 AM

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#6 User is offline   kelvinmead 

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Posted 26 September 2012 - 10:41 AM

View Posttimsabre, on 26 September 2012 - 10:23 AM, said:

I think you may find that 8000 lumens is not bright enough. The 200W lamp fitted in that projector will output at least double that.


ahh, ok. the specs for the machine state;


Brightness (lumens) 2000 ANSI

does this not transpose directly to the lumens of the bulb? or is the projection screen (the dlp / lcd) knock that much off the actual brightness of the bulb?

depending on the size I could try and fit 2 X 100w leds (lumens 16000ish) into the bulb space...

...and then suffer the entire machine melting! ha!

#7 User is offline   MarkPAman 

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Posted 26 September 2012 - 11:05 AM

Although not about a projector*, this thread may be of interest here.



*Actually it is!
MarkPAman"Somtimes I sits and thinks...............and sometimes I just sits"

#8 User is offline   gyro_gearloose 

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Posted 26 September 2012 - 11:22 AM

Quote

I think you may find that 8000 lumens is not bright enough. The 200W lamp fitted in that projector will output at least double that

Its not quite as simple as that. It all depends on how much of the light from the lamp or LED gets captured by the optics system and sent out to the screen, and not simply how much light the lamp/LED produces. Projectors seem to be better than moving heads/mirrors, but for the miniature furnaces that are discharge lamps, cooling must always take precedence over optical efficiency otherwise the lamps die very quickly. Contrast that with high power LEDs which, broadly speaking, send light out of one side and the heat out of the other and thereby allow you to use a more efficient optics system.

If we look at your example of a 200W projector lamp which outputs, lets say for arguments sake, 16,000 Lumens and that this lamp is used a projector which outputs about 2000 Lumens we are left with 14,000 Lumens lost inside the projector. To put that into a stage/theatre context, that's the light output from approximately 1.5 Mac 500s lost between the lamp and the screen. Quite a big loss, yes? I'm not saying that an LED would necessarily be considerably better than a discharge lamp, but if you look at the results of my Miniscan LED conversion then you might be surprised at how close a 2,000 Lumen LED can get to a 300W HMI lamp.

Edit : Must learn to type faster. Thanks for linking to my LED project Mark

This post has been edited by gyro_gearloose: 26 September 2012 - 11:24 AM


#9 User is offline   AHYoung 

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Posted 26 September 2012 - 06:31 PM

im told that much of the recent development in projection technology has been in the area of the lamps there are a couple of manufacturers who can squeeze 20k+ lumens out of 4 lamps and ive got an impressive single lamp 7k unit, 5 years ago you would be knowhere near that. But even though led units have been on the market for a while now, there is nothing anywhere close to event brightness, The newest releases are the Panasonic led units and the produce I think 3.5k , casios can match that but also use a blue laser. Im sure that its only a matter of time before "bright" solid state is available, but lets assume that the development of these units has taken dozens of man years and they havent yet cracked it. Christies parent company are a far easter lightbulb manufacturer so you can expect that theyve had a big team of boffins on it, indeed I was speaking to casio today, and in around 2 years they have sold over 40,000 projectors in the Uk alone, before their solid state, theyde be lucky to sell 1% of that - so that give you an idea what the global return could be, so If you were capable of producing a 5000 lumem solid state projector, basically youd be set for life as it would be worth millions..

#10 User is offline   timsabre 

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Posted 26 September 2012 - 09:29 PM

There's a lot more optical loss in a video projector than in your miniscan project, particularly in the lcd/ dlp panels. No doubt led projection will come but its not bright enough yet.

This post has been edited by timsabre: 26 September 2012 - 09:31 PM

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#11 User is offline   kelvinmead 

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Posted 27 September 2012 - 04:21 AM

luckily, its for a nightclub base, so the super high definition is not a major issue, and the lack of exterior lighting will help also.

ill work on it and see where I get to.

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