Okay, I have been reading for months on various boards, and my project has been on hold for a while. I've decided on most of my final setup, but even now am INCREDIBLY confused about optics, and cannot afford any mistaken purchaces.
I've come to the conclusion that all of this is beyond my mental capacity at the moment, so PLEASE, anyone who knows what they're talking about help me. If this works out, I'll be sure to fully document my progress for the forums; not much else I can offer.
I would forever be in debt to anyone who gives me a fairly definitive setup specific to my situation: (Oh and I have a 9 foot throw distance)
Already Have:
8.9" Toshiba P-2700 16:9 1024x600 Portable DVD Player
Lumenlab 320mm FL, 80mm Diameter Triplet
Soup Ladle Reflector, found here: http://www.diyprojectorcompany.com/catalog/product_info.php?cPath=22&products_id=43
Precondenser, 60mm Diameter, 110mm FL
250w HQI setup with Electronic Ballast
What I need to know is:
What focal length fresnels would be ideal?
Should I cut them to match the panel, or size them larger, and if so how much?
How Far should they be from the LCD and the projection triplet? (I think I will be splitting; Keystoning will probably be necessary for a ceiling mount)
How far should the precondenser be form the bulb?
I know that this is asking a tremendous amount, but I really am stumped. I have been trying, but I need guidance. THANK YOU!
I've come to the conclusion that all of this is beyond my mental capacity at the moment, so PLEASE, anyone who knows what they're talking about help me. If this works out, I'll be sure to fully document my progress for the forums; not much else I can offer.
I would forever be in debt to anyone who gives me a fairly definitive setup specific to my situation: (Oh and I have a 9 foot throw distance)
Already Have:
8.9" Toshiba P-2700 16:9 1024x600 Portable DVD Player
Lumenlab 320mm FL, 80mm Diameter Triplet
Soup Ladle Reflector, found here: http://www.diyprojectorcompany.com/catalog/product_info.php?cPath=22&products_id=43
Precondenser, 60mm Diameter, 110mm FL
250w HQI setup with Electronic Ballast
What I need to know is:
What focal length fresnels would be ideal?
Should I cut them to match the panel, or size them larger, and if so how much?
How Far should they be from the LCD and the projection triplet? (I think I will be splitting; Keystoning will probably be necessary for a ceiling mount)
How far should the precondenser be form the bulb?
I know that this is asking a tremendous amount, but I really am stumped. I have been trying, but I need guidance. THANK YOU!
Okay, after a bit of reading, I've determined that i need the pre-condenser lens 1.5", or 38.1mm away from the bulb (arc, I'm assuming), and 6.3", or 161.2mm from the pre-condenser to the first fresnel. I used a thread that was answered by Guy Grotke for the calculations, so I was hoping that he would be kind enough to double check my math.
Would this be considered "ideal"? or even usable?
The original thread can be viewed here: http://www.diyaudio.com/forums/showthread.php?threadid=51658
Now that the first fresnel is going nearer to the bulb than its focal length, do i also shift the lcd and second fresnel closer?
PLEASE, (Guy especially) help a lost sheep.
Would this be considered "ideal"? or even usable?
The original thread can be viewed here: http://www.diyaudio.com/forums/showthread.php?threadid=51658
Now that the first fresnel is going nearer to the bulb than its focal length, do i also shift the lcd and second fresnel closer?
PLEASE, (Guy especially) help a lost sheep.
feedback
>What focal length fresnels would be ideal?
With 9 foot throw & 320 mm fl triplet, your LCD to lens distance will be 362 mm. So the standard 330 mm fl fresnel will work perfectly for a split design. The condensor fresnel can be anywhere between 180 mm and 220 mm, but I think you have already picked one to use in the precondensor drawing method!
>Should I cut them to match the panel, or size them larger, and if so how much?
Cut them about 1/2" wider than the LCD on all 4 sides. You have to cut opposite sides by exactly the same amount, so the center of the fresnel ends up at the center after you cut.
>How Far should they be from the LCD and the projection triplet? Put the condensor fresnel about 20 mm before the LCD, and the field fresnel about 30 mm after the LCD. That gives you some room to tilt the field fresnel for keystone correction. Closer than 20 mm to the LCD and you will see fresnel rings in the projected image.
>How far should the precondenser be form the bulb?
If you made your own drawing, as per my method, then that is a good starting point. (Even if you screwed it up completely, you could still run without the precondensor lens.) You need to design the arc to precondensor distance, and the precondensor to fresnel distance to be adjustable to start. That may mean a temporary "optical bench" setup to determine exact placement for a non-adjustable enclosure. Fire it up and adjust both until the LCD is evenly lit and the light from the condensor fresnel is not converging or diverging.
>Now that the first fresnel is going nearer to the bulb than its focal length, do i also shift the lcd and second fresnel closer?
Yes, use the [condensor fresnel] 20 mm [LCD] 30 mm [field fresnel] spacing I mentioned above.
>What focal length fresnels would be ideal?
With 9 foot throw & 320 mm fl triplet, your LCD to lens distance will be 362 mm. So the standard 330 mm fl fresnel will work perfectly for a split design. The condensor fresnel can be anywhere between 180 mm and 220 mm, but I think you have already picked one to use in the precondensor drawing method!
>Should I cut them to match the panel, or size them larger, and if so how much?
Cut them about 1/2" wider than the LCD on all 4 sides. You have to cut opposite sides by exactly the same amount, so the center of the fresnel ends up at the center after you cut.
>How Far should they be from the LCD and the projection triplet? Put the condensor fresnel about 20 mm before the LCD, and the field fresnel about 30 mm after the LCD. That gives you some room to tilt the field fresnel for keystone correction. Closer than 20 mm to the LCD and you will see fresnel rings in the projected image.
>How far should the precondenser be form the bulb?
If you made your own drawing, as per my method, then that is a good starting point. (Even if you screwed it up completely, you could still run without the precondensor lens.) You need to design the arc to precondensor distance, and the precondensor to fresnel distance to be adjustable to start. That may mean a temporary "optical bench" setup to determine exact placement for a non-adjustable enclosure. Fire it up and adjust both until the LCD is evenly lit and the light from the condensor fresnel is not converging or diverging.
>Now that the first fresnel is going nearer to the bulb than its focal length, do i also shift the lcd and second fresnel closer?
Yes, use the [condensor fresnel] 20 mm [LCD] 30 mm [field fresnel] spacing I mentioned above.
Don't forget UV protection
The missing items from your list:
UV filter: A piece of Lexan XL10 from Home Depot will do.
IR filter: DIYprojectorCompany has some IR glass cheap. Try doing without it to see if your LCD gets hot. Easy to add later.
Fan: PC fans or bigger fans at Radio Shack.
MOST IMPORTANT: If you can see the MH lamp when it is running, you must have eye protection. At least 99% UV-blocking sunglasses. It can also burn your skin with too much exposure. Even a lamp with a built-in filter still passes 10% of the UV.
The missing items from your list:
UV filter: A piece of Lexan XL10 from Home Depot will do.
IR filter: DIYprojectorCompany has some IR glass cheap. Try doing without it to see if your LCD gets hot. Easy to add later.
Fan: PC fans or bigger fans at Radio Shack.
MOST IMPORTANT: If you can see the MH lamp when it is running, you must have eye protection. At least 99% UV-blocking sunglasses. It can also burn your skin with too much exposure. Even a lamp with a built-in filter still passes 10% of the UV.
thanks for the warnings. I've already gone through a week of toasted red eyeballs; not fun. Now I have a nice pair of shaded UV protected goggles.
I do have a 1/8" sheet of lexan that I will incorporate.
This is a folded design, with a fs mirror turning the image 90 degrees after the fresnels.
For cooling, I have two 90mm fans, one pulling and one pushing air, directly across the bulb. I understand that this is bad for the bulb, and may shorten its life, but oops oh well.
Recieved my monitor today according to the mommy, too bad I just left fo california. I was surprised, half expecting it to be a scam. It was a $500 toshiba dvd player (the 2700 model), and I won it with all accessories, working, for a $100 buy it now price.
Once I strip, i'll start the log.
Thanks again!
I do have a 1/8" sheet of lexan that I will incorporate.
This is a folded design, with a fs mirror turning the image 90 degrees after the fresnels.
For cooling, I have two 90mm fans, one pulling and one pushing air, directly across the bulb. I understand that this is bad for the bulb, and may shorten its life, but oops oh well.
Recieved my monitor today according to the mommy, too bad I just left fo california. I was surprised, half expecting it to be a scam. It was a $500 toshiba dvd player (the 2700 model), and I won it with all accessories, working, for a $100 buy it now price.
Once I strip, i'll start the log.
Thanks again!
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