Is this a good plan?

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#3
I would say go for it. That is what i have based my design on. I checked out the lens and i think i will buy one just for yux. It looks like it might rival my delta IV.... its about half the price too. If you really want to go on the wild side, you could try buying a 7" widescreen lcd... for a 16:9 ratio. Could you tell me how your project is going and mabey post some pictures?

Thanks
 
#4
This is my very first time posting on this fab forum. Please dont slap me for being a total newb. :|

I am planning to use the same basic plans as Mephij. I have one question though: Why not use part number 205-017 on parts express? Costs 10 bucks more, but is 1.6 inches larger. I read somewhere on the forum that bigger is better, so this seems like an obvious choice.

Peter Mitchell
Norway
 
#5
The nice part about the 5" is that you can put it right over the delta IV with out have to space it out further because the delta IV is made for a 5" crt. The problem with his design is he is useing a lens smaller than 5", so yes, he probably should have gone with a bigger lcd, because it will be just as much work to mount etc.
 
#6
Right, after hours of web browsing I now think it all comes down to the 5.6" display from www.partsexpress.com and the 4-1/2" DIA. FUJINON TV PROJ. LENS from www.surplusshed.com for my project too. Anything else i should order while I'm at it? Fresnels for example? I live in Norway and it seems to be VERY limited as to what can be found here for parts. Therefore i want to be sure i have everything, as ordering from the states aint exactly cheap.

I was also wondering if someone could recommend a light source? I know it has been discussed in other threads but it seems to me a good solution is yet to be . All I'm looking for is a cheap yet bright source (Yes, yes, I know everyone else is too 😛). The one zark's using seems like a good solution. I can get a halogen light source cheap. It is rated to 16k lm but there's no info about colour temp, and the bulbs have an average life span of 50 hours so I dont think I'm settling for that one. Any ideas?

Oh yeah: is www.diyprojector.com temporarily down or shut down for good?

Peter Mitchell
Norway
 
#8
If i should buy the 4 inch module (www.partsexpress.com #205-050) instead of the 5.6 inch (www.partsexpress.com #205-017) would it be a noticable decrease in quality on the screen? The 4 inch module has a little lower resolution, but will this be very noticable when for example watching a movie?

The reason for wanting to buy the smaller panel is obviously to simplify construction. I'm definatly going for the 4-1/2" DIA. FUJINON TV PROJ. LENS from www.surplusshed.com.
 
#9
lets say you are watching a movie with a 4 foot screen. With the 5.6, you would have much better res than the 4 at that size. But if you made the screen smaller, lets say 3 feet with the 4, you would have bett resolution. I guess what im trying to get at, is you picture quality all depends on the size of the output of you projector.
 
#10
mustafa,

i am going to have to disagree with you here.

the 5.6" module is 960 x 234, which suggests the specs are counting all R,G, and B pixels... which puts the resolution at 320 x 234, which is a much more common resolution for this size/price of panel.

on the other hand, the 4" module is 383 x 234, which appears to be the real pixel count, which would actually make 4" module higher resolution than 5.6" module.

Also -- if he got the 5.6" screen with the 4.5" fujinon lens, he wouldnt be able to get the whole picture. This is a CRT lens, which is made to be right up against the CRT. this means the source image must be AT MOST 4.5" diagonal.

just wanted to interject before he drops $100 on something he will have trouble using.
 
#14
The lcd and the lens are now ordered. Eta: probably about 1-2 weeks as I live in Norway.

Now for the light source. The best solution would be finding something in Norway, but it doesnt seem like anyone sells MH bulbs. Any suggestions as to where they can be found? I dont want to order it from the states. The lens cost about 15 bucks but the shipping set me back over $20 and with the vat I'll have to add in Norway the lens alone will set me back allmost $40! That's more than twice the price of the lens itself! 🙁 Therefore I'll probably need an alternative light source. I want to make this thing as small and compact as possible (not having to space the lcd from the lens helps a great deal i suppose 😀) so huge lights are not an option. Any suggestions? How about a light source from an old slide projector? Will be using it for watching movies in the dead of night mostly, but would be nice to get a viewable picture at daytime too.

Sure will jvisaria 🙂. I'll try to put in a few pics when I'm done, but dont expect it to be anytime soon. It will hopefully be finished early januar, or maybe before if I can get some time off work before christmas.

Peter Mitchell
Norway
 
#17
Using a lcd that is bigger than your lens

You can use a lcd that is bigger than your projection lens if you place a lens between your lcd and the projection lens. You simply need to arrange the lenses and lcd so that the image from the first lens is projected at an appropriate distance from the projection lens.

Things worth noting:

1. This can take a substantial amount of space (since the focal length of most readily available lenses is on the order of 12".

2. The focal length issue can be compensated for with a series of two or more lenses (more lenses equals more distortion thogh).

3. Inversion of image issues. if you place another lens in the optical path to the projection lens, your image may be inverted.

4. The larger lens you use the more light you can collect, and thus you will have a brighter image.
 
#18
Shibby...

I bought 2 LCDs from partsexpress a 4" module, and a 5.6" module. The 4" module cannot be used for a projection system because it cannot be disassembled appropriately. The 5.6" can be disassembled appropriately, but is too large for my projection lens. I bought the Fujinon 4.5" lens

What kind of lens can I put between the LCD and the projection lens to make this combination work well?
 
#19
Lucca,

I found a 7" magnifying lens from Surplus Shed on their Magnifier's page that I think might work for the 5.6" size LCD (I've got the same size, different than the parts express one though).

You might need a concave lens with the negative focal length of the convex magnifying lens to balance out the image, but I know that Surplus Shed sells a lens that is about 5" or so and would work with a projection lens and it has a focal length that is negative of the magnifyer. I think the focal lengths are 500mm (~20 in), and I'm not sure how far apart from each other would shrink it from a 5.6" down to a 4" or so.

Hope that helps. Sorry if I was vague.

--Clint
 
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