Hello everyone. I ran across this in Popular Science and thought I might give it a try. I looked at all the different plans and the sizes of each one. I thought to myself how small can i make one so I downloaded all of the tools to calculate everything. This is what I have so far, if I am on the right track some feed back would be gladly appreciated.
Size of object to be projected in inches (ie. your LCD panel):
inches 7"
Distance from projector lens to screen in inches:
inches 228"
Size of projected image in inches:
inches 96"
Focal length of lens in inches:
inches 15.50"
Full Version: 7' Lcd Projector
QUOTE (Ecks @ Oct 24 2006, 09:10 PM) 
Hello everyone. I ran across this in Popular Science and thought I might give it a try. I looked at all the different plans and the sizes of each one. I thought to myself how small can i make one so I downloaded all of the tools to calculate everything. This is what I have so far, if I am on the right track some feed back would be gladly appreciated.
Size of object to be projected in inches (ie. your LCD panel):
inches 7"
Distance from projector lens to screen in inches:
inches 228"
Size of projected image in inches:
inches 96"
Focal length of lens in inches:
inches 15.50"
Size of object to be projected in inches (ie. your LCD panel):
inches 7"
Distance from projector lens to screen in inches:
inches 228"
Size of projected image in inches:
inches 96"
Focal length of lens in inches:
inches 15.50"
Its best to work the other way: determine what lens you want to use then input its focal length and the LCD size and calculate the projection size to throw distance. Throw is adjustable to get the image size you want, lens focal length is not.
QUOTE (tameone @ Oct 24 2006, 09:13 PM)
Its best to work the other way: determine what lens you want to use then input its focal length and the LCD size and calculate the projection size to throw distance. Throw is adjustable to get the image size you want, lens focal length is not.
Ok Thanks I will give it a try. Not sure what i'm doing yet but I will keep at it.
QUOTE (Ecks @ Oct 24 2006, 09:20 PM)
Ok Thanks I will give it a try. Not sure what i'm doing yet but I will keep at it.
the standard LL 320mm triplet is most commonly used and works well with small LCDs. If you noticed, thats the default value that pops up in focal calc 2
That combined with 7" LCD and 228" throw (19ft, thats a long throw) gives a 120" diagonal projection. If you want 96" diag with that setup, you will need a throw of ~15.5ftall that is for an unsplit fresnel setup which is best used when the PJ can be placed directly in the center of the screen.
QUOTE (tameone @ Oct 24 2006, 09:25 PM)
the standard LL 320mm triplet is most commonly used and works well with small LCDs. If you noticed, thats the default value that pops up in focal calc 2 That combined with 7" LCD and 228" throw (19ft, thats a long throw) gives a 120" diagonal projection. If you want 96" diag with that setup, you will need a throw of ~15.5ft
all that is for an unsplit fresnel setup which is best used when the PJ can be placed directly in the center of the screen.
That combined with 7" LCD and 228" throw (19ft, thats a long throw) gives a 120" diagonal projection. If you want 96" diag with that setup, you will need a throw of ~15.5ftall that is for an unsplit fresnel setup which is best used when the PJ can be placed directly in the center of the screen.
Thanks, i came up with the same thing. now i know where to start.
Ok back at it for the second night. Last night i got some good info on uesing a 7" LCD, all today at work I was all over this Form looking for some info on how to figure out the placement or should I say the spacing of the Fresnel-LCD-Fresnel Or Fresnel-LCD if there is a calcuator to help me figure this out can someone point me in the right direction. This will help me finish my design and I can start on the build.
T.I.A
T.I.A
QUOTE (Ecks @ Oct 25 2006, 09:18 PM)
Ok back at it for the second night. Last night i got some good info on uesing a 7" LCD, all today at work I was all over this Form looking for some info on how to figure out the placement or should I say the spacing of the Fresnel-LCD-Fresnel Or Fresnel-LCD if there is a calcuator to help me figure this out can someone point me in the right direction. This will help me finish my design and I can start on the build.
T.I.A
T.I.A
no calculator, just rules of thumb.
split -> fresnel LCD fresnel --
center of bulb to fresnel = focal length of fresnel, generally 220mm
fresnel to LCD = 10-15mm
LCD to fresnel = enough room to keystone, generally 20mm
unsplit -> fresnel fresnel LCD
center of bulb to fresnel = 220mm
fresnel to fresnel = 0 - 10mm (some people stick them together, but I'm using ~10mm)
fresnel to LCD = 10-15mm
QUOTE (tameone @ Oct 25 2006, 10:18 PM)
no calculator, just rules of thumb.
split -> fresnel LCD fresnel --
center of bulb to fresnel = focal length of fresnel, generally 220mm
fresnel to LCD = 10-15mm
LCD to fresnel = enough room to keystone, generally 20mm
unsplit -> fresnel fresnel LCD
center of bulb to fresnel = 220mm
fresnel to fresnel = 0 - 10mm (some people stick them together, but I'm using ~10mm)
fresnel to LCD = 10-15mm
split -> fresnel LCD fresnel --
center of bulb to fresnel = focal length of fresnel, generally 220mm
fresnel to LCD = 10-15mm
LCD to fresnel = enough room to keystone, generally 20mm
unsplit -> fresnel fresnel LCD
center of bulb to fresnel = 220mm
fresnel to fresnel = 0 - 10mm (some people stick them together, but I'm using ~10mm)
fresnel to LCD = 10-15mm
Thanks for all the help.
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