I know that when I used to visit this site back in the day there was some talk about using LEDs as a light source. Has anyone done this? I emailed a site about this and here is what they said
That conversion is fairly complicated but here is what I have found on it:
Candlepower is a rating of light output at the source, using English measurements.
Foot-candles are a measurement of light at an illuminated object.
Lumens are a metric equivalent to foot-candles in that they are measured at an object you want to illuminate.
Divide the number of lumens you have produced, or are capable of producing, by 12.57 and you get the candlepower equivalent of that light source.
By this it would take: about 40 of the 8000mcd (8.0cd) to produce 4000 lumens.
from what I am reading it looks like I would only need 40 leds to reach the light levels for a projector. Is this right? The LEDs were only about $1.40 each so this also seems very cost effective.
So here is what I was thinking. I need a projector and an LCD. I can gut the projector and install the leds and power supply (how would I power these?). Would I need a reflector? Could I just evenly space the leds on a board that is the same size as my led?
What do you guys think?
That conversion is fairly complicated but here is what I have found on it:
Candlepower is a rating of light output at the source, using English measurements.
Foot-candles are a measurement of light at an illuminated object.
Lumens are a metric equivalent to foot-candles in that they are measured at an object you want to illuminate.
Divide the number of lumens you have produced, or are capable of producing, by 12.57 and you get the candlepower equivalent of that light source.
By this it would take: about 40 of the 8000mcd (8.0cd) to produce 4000 lumens.
from what I am reading it looks like I would only need 40 leds to reach the light levels for a projector. Is this right? The LEDs were only about $1.40 each so this also seems very cost effective.
So here is what I was thinking. I need a projector and an LCD. I can gut the projector and install the leds and power supply (how would I power these?). Would I need a reflector? Could I just evenly space the leds on a board that is the same size as my led?
What do you guys think?
I must of misread somewhere, I though you could get away with using 4000 lumens (thats what the lowest recomended amount of light is for a projector).
Ok when you say collimate you mean focused right (I am new to video, I'm an audio guy). IF thats what you mean then all I have to say is that I was hopping I could bypass it by spreading out the leds. They radiate most of their light to the front.
Ok when you say collimate you mean focused right (I am new to video, I'm an audio guy). IF thats what you mean then all I have to say is that I was hopping I could bypass it by spreading out the leds. They radiate most of their light to the front.
I dont know what the minimum lumen are for a OHP. I've retrofitted mine with a 150W MH (12000 bulb lumen) and its bright enough when the room is dark (100" screen diag.)
It all depends on efficiency i guess.
As far as I know no one managed to built a multi-light PJ upto now.
There are major problems directing the light. See also the topic "Solux the perfect light source..."
It is not enough to get the light to the fresnel, it also has to have the EXACT wright angle.
We need an optics expert to figure out a way to compress the light from multiple sources to 1 point source. (prisms??)
It all depends on efficiency i guess.
As far as I know no one managed to built a multi-light PJ upto now.
There are major problems directing the light. See also the topic "Solux the perfect light source..."
It is not enough to get the light to the fresnel, it also has to have the EXACT wright angle.
We need an optics expert to figure out a way to compress the light from multiple sources to 1 point source. (prisms??)
DJNUBZ, unfortunately your conversion from candelas to lumens is inaccurate. Candelas are a measurement over a given spherical "area", whereas LUMENS represent the total amount of light output from the source. To convert from candelas to lumens, you need to know the candela output and the angle of irradiance. You probably will want to make some adjustments based on how the irradiance level drops.
The brightest long life White LEDS currently available are the 1 watt (actually 1.2) LEDS from Lumileds. They are approximately 23 lumens. To get 4000 Lumens you would need 200 of them. They are about $5 each or more. When you work the life into the calculations, they are still pretty cheap.
Alvaius
The brightest long life White LEDS currently available are the 1 watt (actually 1.2) LEDS from Lumileds. They are approximately 23 lumens. To get 4000 Lumens you would need 200 of them. They are about $5 each or more. When you work the life into the calculations, they are still pretty cheap.
Alvaius
New 5W 120lumen LEDs
Hello, I am new to this forum and new to Projector makin , but have been looking into it and found that lumiled makes a 120 Lumen white light LED whose specs can find found here: http://elektrolumens.com/pdf_files/Luxeon_Star_5W_Specs.pdf. What do you guys think about these?
Hello, I am new to this forum and new to Projector makin , but have been looking into it and found that lumiled makes a 120 Lumen white light LED whose specs can find found here: http://elektrolumens.com/pdf_files/Luxeon_Star_5W_Specs.pdf. What do you guys think about these?
Even with 120 lumens a pop, let's say that 4000 lumens is the standard to produce a decent projection image, at $25.50 (light + collimator) a piece, it would cost you $850 for about 33+ LEDs. Then you have to wire them and also arrange them in a way that you will use the maximum amount of light.
I think that LEDs are still not the way to go for now! Just my 2 cents! 🙂
Tommy
I think that LEDs are still not the way to go for now! Just my 2 cents! 🙂
Tommy
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