Does everything have to be adjustable for fine tuning? Can i mount the LCD and Collimator permanently? If i mounted them permanectly and allowed the triplet, lamp, and field lens to be adjusted, would that allow me to fine tune everything?
Also in this diagram it is showing that the LCD and collimator have a .6 inch gap between them right?
Full Version: Adjustability
I responded to this once but it seems to have been lost in the void of cyber-space so ... here goes again.
This is one of those questions that I grappled with when first doing research but I couldn't get a definitive response, so I went a bit overboard on the adjustability of my pj. Take a look at my PLOG if you are interested...
Being a couple of months wiser, I will outline the absolute minimum, in my opinion, that you should have adjustable in order to get excellent results. Keep in mind that my pj isn't done as yet, so take this for what it's worth.
1) The bulb to collimating fresnel distance must be adjustable to obtain even illumination. This can be accomplished by having an adjustable lamp, or an LCD sled which can be moved.
2) The bulb must be centered with the centers of the fresnels/LCD/and triplet. It helps to have an up/down adjustment for the bulb because sometimes the arc doesn't occur in the exact center of the bulb packet. Moving the bulb up/down a bit can help reduce spillage on the triplet. The left/right (depth) position of the arc is of less importance; as long as the arc packet is centered it should be fine.
3) The collimating fresnel LCD distance can be fixed per spec. The farther the collimating fresnel is from the LCD, the less bright the projection, since brightness drops off with the square of the distance (distance*distance).
4) The field fresnel should have the following adjustments:
Back/Forth from LCD - needed to optimize light cone pattern on triplet and for keystone tilting.
UP/Down - To help the light cone hit spot on the triplet.
Tilt: for keystone correction
5) Reflector should have the following:
Distance from bulb (back/forth)
Up/Down: to center with arc
Reflector should be square to the collimating fresnel.
The more that is tweakable, the better the potential for excellent results, but the greater the complexity/build time. You do reach a point of diminishing returns after implementing the above.
Hope that helps. Good luck.
This is one of those questions that I grappled with when first doing research but I couldn't get a definitive response, so I went a bit overboard on the adjustability of my pj. Take a look at my PLOG if you are interested...
Being a couple of months wiser, I will outline the absolute minimum, in my opinion, that you should have adjustable in order to get excellent results. Keep in mind that my pj isn't done as yet, so take this for what it's worth.
1) The bulb to collimating fresnel distance must be adjustable to obtain even illumination. This can be accomplished by having an adjustable lamp, or an LCD sled which can be moved.
2) The bulb must be centered with the centers of the fresnels/LCD/and triplet. It helps to have an up/down adjustment for the bulb because sometimes the arc doesn't occur in the exact center of the bulb packet. Moving the bulb up/down a bit can help reduce spillage on the triplet. The left/right (depth) position of the arc is of less importance; as long as the arc packet is centered it should be fine.
3) The collimating fresnel LCD distance can be fixed per spec. The farther the collimating fresnel is from the LCD, the less bright the projection, since brightness drops off with the square of the distance (distance*distance).
4) The field fresnel should have the following adjustments:
Back/Forth from LCD - needed to optimize light cone pattern on triplet and for keystone tilting.
UP/Down - To help the light cone hit spot on the triplet.
Tilt: for keystone correction
5) Reflector should have the following:
Distance from bulb (back/forth)
Up/Down: to center with arc
Reflector should be square to the collimating fresnel.
The more that is tweakable, the better the potential for excellent results, but the greater the complexity/build time. You do reach a point of diminishing returns after implementing the above.
Hope that helps. Good luck.
Good post Sonic!
That's going to help out a lot of people including me. I had no idea the arc in the bulb didn't necessarily happen dead center.
I'm plan on having a lot of remote adjustabilty in my PJ and thought I may be overdoing it but now I feel justified in my overengineered approach.
That's going to help out a lot of people including me. I had no idea the arc in the bulb didn't necessarily happen dead center.
I'm plan on having a lot of remote adjustabilty in my PJ and thought I may be overdoing it but now I feel justified in my overengineered approach.
QUOTE (hardflip @ May 29 2005, 12:18 PM)
Good post Sonic!
That's going to help out a lot of people including me. I had no idea the arc in the bulb didn't necessarily happen dead center.
I'm plan on having a lot of remote adjustabilty in my PJ and thought I may be overdoing it but now I feel justified in my overengineered approach.
That's going to help out a lot of people including me. I had no idea the arc in the bulb didn't necessarily happen dead center.
I'm plan on having a lot of remote adjustabilty in my PJ and thought I may be overdoing it but now I feel justified in my overengineered approach.
My pleasure, glad to help!
BTW: Is that Ron Jeremy in your avatar?!
yeah. i did a quick search on google under avatar and he popped up. I found it quite amusing so 'borrowed' it. 
QUOTE (hardflip @ Jun 3 2005, 05:29 PM)
yeah. i did a quick search on google under avatar and he popped up. I found it quite amusing so 'borrowed' it.
Ron Jeremy... Now one of HIS movies would be scary to watch on a 120" screen!
Talk about "larger than life" ...
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