DIY Video Projector

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#2,081
ChuckReese said:
If you have an elliptical mirror with a 32" focal length, then you can get 4x magnification of an LCD at about 10 feet without the need for any projection optics.
CR [/B]
Click to expand...

???????????
Are you shure on that?

Watching all these ideas about reflectors i wonder, why nobody has come with the suggestion to use a fresnel + mirror behind as a reflector. If a plane mirror is attached behind a lens, they together act as a spherical mirror!

xblocker
 
#2,083

this is what im working on @ the moment

final got this picture stuff down
 
#2,096
Using an slide projector

Hello

I'm really new to all this stuff, I have been researching about home made projectors since a week ago.

I had an idea and I would like to read your opinions about this.

I want to take my sister's slide projector and put a 1.8" LCD display in the place the slides are. ?Do you think it could work?

I want that projector to view films from my bed to the ceiling and both the size of the projected image (tested with a usual slide)and the 280x220 resolution (tested with photoshop) is enough for me.

Thanks
 
#2,098
ChuckReese, Xblocker,
thank you for your help, now I know for sure what kind of lenses should I use to eliminate abberation problem.

BTW, if you don't mind, I would like to know brightness comparison on the screen, between projector with LCD panel and without.
let say, without LCD panel the projector brightness is 100%,
now, with LCD panel in place, projector brightness reduce to 50% or 40% or ...?
Someone, I forgot the name, told that placing LCD panel in reverse (Front surface, become facing the lamp) make some gain in brightness, is it true?
 
#2,099
Biteon,
nice drawing, but sorry, it can't work! This has been explained several times here, and again, placing a lightsource in an off-axis area will result in an off-axis light collimation. Here's a pic with examples using 2 light sources.

xblocker
 

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#2,100
thank you for your help, now I know for sure what kind of lenses should I use to eliminate abberation problem.
Click to expand...

Ok, I'm still a bit confused. What kind of lens do I need? What's a doublet? If it's two PCX lens or a DCX lens, then why does my DCX lens produce a blurrier picture than my PCX lens?


I've tried all the lenses from my split-open fujion lens setup (has a planar concave, planar convex, double convex, and some funny partially double convex correction lens) and the thing that works best is the PCX. I've tried all sorts of combinations of them and really the DCX is more blurry than the PCX.


Before i waste more money on lens, just what does a doublet or triplet look like? and what lens are you planning to get?
 
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