I have attached an image on this post of what i got so far. I have all the lenses and bulbs etc in place, i tooke a pic of a somewhat screen and i got alot of liens branching outwards from the middle which is comming from the fresnels, but isnt the actual fresnel grooves that you get from putting it too close to the LCD. Also in the picture, the LCD is NOT in because i cannot hook up to a source yet. If i put the LCD in place will that get rid of the lines or is this caused by something else. I hooked up the LCD before and focused an image of a box on the screen that says no input device detected and it focused very well but you can slightly see those lines on the white writting. Anyone know what is causeing it?
I added 2 pictures, both are the same but the one that looks more green is when the bulb wasnt warmed up that long and the other ones has some other colours comming in and that is when the bulb was on for about 5 minutes.
I added 2 pictures, both are the same but the one that looks more green is when the bulb wasnt warmed up that long and the other ones has some other colours comming in and that is when the bulb was on for about 5 minutes.
Attachments
What is the projection lens that you are using? Try to get the arc of your bulb in focus and see if it is still green. If it is it may be that your lens isn't corrected for abberration.
How do i get the arc in focus, im not really sure what you mean?
Also, its not really that green, just a tiny bit. It s pretty much the camera that makes it look more green. Im more worried about those spiral looking lines comming out from the middle and that im not getting even light distribution, just a circle sort of .
Also, its not really that green, just a tiny bit. It s pretty much the camera that makes it look more green. Im more worried about those spiral looking lines comming out from the middle and that im not getting even light distribution, just a circle sort of .
I would guess those lines are the result of the arc reflecting off of your reflector? There is no LCD in there so that's not the culprit. I'd say just focus the arc. Do this by adjusting the fresnels until you get a nice picture of your arc (from the bulb) on your wall. Then slap that LCD in (at the right distance) and go to town!
wait, what do you mean focus till you can SEE the arc on the screen. isnt' the fresnel supposed to diffuse the light evenly on the screen withn no hot spots? seeing the arc is seeing a hot spot right?
I dont have a reflector in yet either but nothing is painted blaack yet so could that be it?
Ya, i was thinking the same thing as snortonnorton, wont that mean that gives me a gross hotspot if i do that.
Ya, i was thinking the same thing as snortonnorton, wont that mean that gives me a gross hotspot if i do that.
yeah, but i'm thinking the lcd itself will also spread out some of the light.
what is your distance from the bulb to the fresnel?
and maybe you should try it with the lcd first before you change too much.
what is your distance from the bulb to the fresnel?
and maybe you should try it with the lcd first before you change too much.
Its 220mm from arc to first fresnel and im using the unplit design so both are together, lcd 20-30 mm aprox. after. the pj lens is about 14.86" i think i calculated it to be but its on a sliding piece so i can move it further or closer.
An d about the lcd, i cant put it in just yet because i need to hook it to my computer because i need a somewhat white screen because now all it is is black and it looks fine, until i take it out and see what is in the pictures.....
An d about the lcd, i cant put it in just yet because i need to hook it to my computer because i need a somewhat white screen because now all it is is black and it looks fine, until i take it out and see what is in the pictures.....
The image of the arc should be focussed at the optical centre of the objective lens. The lens should in turn be focussed on the LCD.
you could try moving your lens closer. you sayed its 14.86" away 327mm is just over 12"
try this
http://www.industrial-enclosures.com/html/conversion-mm-inch.html
try this
http://www.industrial-enclosures.com/html/conversion-mm-inch.html
I used all the conversion tools. And about moving the lens , i do, i have it on a slide so i can move it from 5mm to 17mm ish.. And when i move it, it still doesnt make a difference with the problems with the light.
Thanks for that url though, thats what i needed a month ago 🙂
Thanks for that url though, thats what i needed a month ago 🙂
the site is a big help i found it on google sence i dont know mm its a big help. maybe try shining a flashlight through your lens see if it puts out a green then if so your lens may have a greenish tint maybe.
Stupid question.
Did you remove the green tinted film from your lexan?
Also try moving your lens away from the fresnel just a bit. May be close to being focused in infinity and that is where your getting the spiral lines. Very slight bend in fresnel causing slight diferance in outer pattern. Or you accedently got your fresnels swapped.
Did you remove the green tinted film from your lexan?
Also try moving your lens away from the fresnel just a bit. May be close to being focused in infinity and that is where your getting the spiral lines. Very slight bend in fresnel causing slight diferance in outer pattern. Or you accedently got your fresnels swapped.
No Problem. You got to it almost immeadiadtly and it is a nessearry evil I guess. Just an inconveniance. Thanks
my1423 said:
Actually i just tested this once for 10 minutes and i didnt put the lexan in yet so thats not it but at first i thought i did that. I only tested it for 10 min kuz without the lexan, i didnt want to damage the fresnels. The fresnels are not swapped, i triple checked that too after.... What a pickle!
spiral interference pattern
This is caused by have a slight misalignment of the two fresnel centers. You see a pattern of cancelled and reinforced light made where the rings in one fresnel interfere with the action of the rings in the other. I have seen a pattern that looks like a Japanese flag too. Shuffle one of those fresnels around a bit, relative to the other fresnel, until the pattern goes away. Or you can just space them 10 mm apart, and avoid the problem entirely.
You do need to run a new MH lamp for a while before it stabilizes. Some of the colors may fade out once it really gets going. Try running it for 20 minutes.
This is caused by have a slight misalignment of the two fresnel centers. You see a pattern of cancelled and reinforced light made where the rings in one fresnel interfere with the action of the rings in the other. I have seen a pattern that looks like a Japanese flag too. Shuffle one of those fresnels around a bit, relative to the other fresnel, until the pattern goes away. Or you can just space them 10 mm apart, and avoid the problem entirely.
You do need to run a new MH lamp for a while before it stabilizes. Some of the colors may fade out once it really gets going. Try running it for 20 minutes.
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