gui_999 said:Well, the work bowed is not in my vocabulary 😕
my fault how about curved upward or bent upward
Hmmm...I've been looking at OHPs and I haven't notice the Fresnel being bowed on any of them...What is this about a bowed fresnel?
Tomorow I'll test the split fresnel setup, with 2 fans under the lcd pushing air, I hope the heat problem will be gone.
And like proto5 said to me in a email, I'll have to raise my projection lens to focus, but on the elmo it's a static arm, I can't move it up and down. But I have an idea for this, it's not really a problem
And like proto5 said to me in a email, I'll have to raise my projection lens to focus, but on the elmo it's a static arm, I can't move it up and down. But I have an idea for this, it's not really a problem
Wierd....I noticed that different OHPs have the grooved side facing differently, either toward or away from the light, but i haven't noticed the bow.
??? There is no "grove side" for OHP fresnels, because it is two fresnels glued together, with the groved side of each fresnel in the inside.
I have seen OHP fresnels that don't have a bow to them. If you forgot which one it was, put them back together and check it out.
I have seen OHP fresnels that don't have a bow to them. If you forgot which one it was, put them back together and check it out.
Lifter
I've seen OHPs that have the grooved sides facing outwards.
And from reading the Fresneltech pdf it seems that the only difference between grooved side and smooth side on a single fresnel is a slight aberration. Same thing with plano-convexes.
I've seen OHPs that have the grooved sides facing outwards.
And from reading the Fresneltech pdf it seems that the only difference between grooved side and smooth side on a single fresnel is a slight aberration. Same thing with plano-convexes.
split fresnels
I cut mine the same way Qui did....with a cutoff wheel slicing BETWEEN the 2 lenses. This way the lower one still fits in the stock holder. To check FL of the lenses do them INDIVIDUALLY, not together! The lower is 9", and the upper is 12".
I cut mine the same way Qui did....with a cutoff wheel slicing BETWEEN the 2 lenses. This way the lower one still fits in the stock holder. To check FL of the lenses do them INDIVIDUALLY, not together! The lower is 9", and the upper is 12".
Ok, everything is working! I'm even able to focus without putting the projection lens higher.
Only problem I see, is that fresnels are bowed, so my top fresnel is bowed like this __-----------__ resulting in a curved picture, worst than with glued fresnel, but I can manage with it!
The purpose of this design was to eliminate heat problem.. well I does solve it! I totaly rebuild the top part of the OHP with cardboard, on which I put my plexiglass setup that have the fresnel on it. I left spaces on each side so I can put a table fan to push air on top and back of the lcd. This way, my lcd is WAY MORE COOLER!
And I can still see hot spots
But I think it's the mirror that need to be changed.
So does it worth it? for heat.. YEAH! for all the headache, NO!
Only problem I see, is that fresnels are bowed, so my top fresnel is bowed like this __-----------__ resulting in a curved picture, worst than with glued fresnel, but I can manage with it!
The purpose of this design was to eliminate heat problem.. well I does solve it! I totaly rebuild the top part of the OHP with cardboard, on which I put my plexiglass setup that have the fresnel on it. I left spaces on each side so I can put a table fan to push air on top and back of the lcd. This way, my lcd is WAY MORE COOLER!
And I can still see hot spots
But I think it's the mirror that need to be changed.
So does it worth it? for heat.. YEAH! for all the headache, NO!
I think I'm finished with my projector! 😎
I've just finished to glue my replacement cardboard OHP top. Allmost no light escape the ohp. The only thing I could do is a "piramidal" enclosure from my lcd to the projection lens, and test that fu******** V looking spot in the middle of my screen, I think it's the mirror.
Like I said, the only thing I "hate" is that curved picture, but now It doesn't heat! Good compromise I think 😉
So tomorow I'll install my setup in the restroom, rent a dvd.. And look the result of 2 weeks of hard work!!!
It's 1h am here.. so I'm going to sleep!
Oh and.. what should rent? maybe I could take look at that matrix 2 svcd that's lost somewhere on my HDD. lol
I've just finished to glue my replacement cardboard OHP top. Allmost no light escape the ohp. The only thing I could do is a "piramidal" enclosure from my lcd to the projection lens, and test that fu******** V looking spot in the middle of my screen, I think it's the mirror.
Like I said, the only thing I "hate" is that curved picture, but now It doesn't heat! Good compromise I think 😉
So tomorow I'll install my setup in the restroom, rent a dvd.. And look the result of 2 weeks of hard work!!!
It's 1h am here.. so I'm going to sleep!
Oh and.. what should rent? maybe I could take look at that matrix 2 svcd that's lost somewhere on my HDD. lol
If you want to really test the system play an original... that svcd matrix will not look as good as you might think! I've found Star Wars Episode 2 to be a great DVD for overall picture quality.
ok just a few updates to my projector
first i would like to give a big thanks to ace 3000_1 for lending some expert advise on my project thanks ace
now all these are tests and they look much better in person so
bear with me this is just some comparisons for the changes i made by no means is this thing done
and now for some screen shots
this is a picture before i split the fresnel in complete darkness
and about 80"
first i would like to give a big thanks to ace 3000_1 for lending some expert advise on my project thanks ace
now all these are tests and they look much better in person so
bear with me this is just some comparisons for the changes i made by no means is this thing done
and now for some screen shots
this is a picture before i split the fresnel in complete darkness
and about 80"
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