First of all, thanks in advance to anyone who helps me with this issue.

I am looking to build a projector based on a 20" screen I got a sweet deal on. Specs are:

LCD Panel
20.1" 16:9 wide WSXGA TFT LCD

Resolutions
Ultra High WSXGA+ 1680x1050/60Hz,
1280x720/60Hz, 1024x768/75Hz

Brightness & Contrast Ratio
Brightness: 300 nit (cd/m²)
Ultra high Contrast ratio 800:1

Response Time(GTG)
8ms

My question is how does this larger screen size affect design and components. For example the fresnels will not be large enough for this screen, where would I look to find larger ones, and how large? Also, are there any formulas to calculate projection size vs distance from projector?

I haven't scoured all the forums yet, but have looked through most and haven't found what I'm looking for yet. Again, any advice will be greatly appreciated.

Thanks,

Bill

There are some concerns that I would consider the greatest hurdles with using a 20" LCD.
1) You will need to find fresnels large enough to cover the size of the LCD.
2) You will need to find a triplet whose FOV can "see" the entire LCD
3) You will get much darker corners than a 15" or 17" design due to the physics of light.
4) You're throw will be short even using a pro triplet.
5) Due to the short throw you will need keystoning, therefore you will need to address the shortcomings.

Take a look at Dazzzla's focal length calculator for determining throw.

I would say at the moment, the 17" panel is the largest practical size... if you want more resolution, then there is the 15.4" WUXGA panel/controller. There are other small, high res panels out there, but I have yet to see someone put together a panel/controller for use in a DIY PJ.

Hope this answers some of your questions.
cheers,
gs