My 19" LCD Projector

[Mikey p]

If you are building a straight through design, then it should be as tgreenwood said. If you are building a folded design that will use a mirror, then it has to be right side up as the mirror will invert the image before it reaches the projection lens. When you build your projector I strongly recommend you build a test bed first. This allows you to adjust the distances to get the best picture before you build the final box. Although the focal length calculators are accurate, there is always the final tuning of distances to get right depending on what your design is. Also remember to leave room if in the future you want to add a precondenser lens, as the distances will change with that application.

[gssmind]

I had straight through design in mind but am not sure really on which one to go with as I have not build one before.

Which one would you go with if you were in my situation?

I have seen examples of both "straight through design" and "folded design" but am not sure of the differences between the two design in terms of quality, besides one taking more room then the other.

[Mikey p]

Straight through split design- one fresnel on each side of the lcd. Projector sits on the floor and can be angled upwards while the front fresnel is tilted perpendicular to the screen. This is called keystone corection. It works to a maximum of 15 degrees. Slightly less clear picture then unsplit, some people say.
Straight through unsplit sesign- both fresnels are behind the lcd. Projector must be put on a stand and raised so the projection lens is centered to the screen and kept level as there in no keystone correction in this design. This is the design with the clearest picture.
Foled design- uses a mirror to bend the image 90 degrees. This allows the projector to be built vertically to save space. The only drawback is the mirror adsorbs some of the light so less gets through to the screen. Which is no big deal now that there are proper reflectors and precondenser lenses that are now being used. The diy projector has come along way in the last year or so. There are lots of these designs at LumenLab in the plog section. Check it out, I'm sure you'll see something there that you'll like.

[gssmind]

I am still not sure if I mounted my LCD properly but I am not worried about it at the moment, atleast I know for sure that it works. Its just a matter of flipping it properly. I can do that later aswell.

I order two of the things from LumenLab yesterday: "LL65K T15 Kit" And their "Pro Reflector" to get me started having some of the items one-by-one.

Looking at the plog section, I have decided to go with Split design with 2 frensel. I will draw the design up using Google Sketch but have to figure out the exact size of frensel etc etc.

I have to figure out (1. The two Fresnel Lenses I need and 2. Pro Lense) and I would pretty much have all my ingredents to put this puppy together.

I am bidding on this lense:
http://cgi.ebay.com/ws/eBayISAPI.dll...MEBI%3AIT&rd=1

Is that good you think, that is the same size lense 'superdaveumo' used for his 17" and his calculation showed that it would work for a 19"?

[Mikey p]

An 18 inch opauqe projector lens doesn't have perfect corner to corner focus on a 17 inch lcd. No chance it working on a 19 inch lcd unless you're willing to accept blurry corners. Check out the plog from "ChristmasGT" and see where he changed to a Pro lens to get good corner focus. And that was a 17 inch lcd, not a 19 inch.
As far as ordering fresnels, the lamp side will have to be a 330mm focal length if you are using a reflector, and the front fresnels focal length is determined by the focal length of the projection lens you are going to use.

[gssmind]

Thanks Mikey, You have been a lot of help.

Here is what I have in mind. I will bid for the 18" lens, if I get it then I will see how the results are and if not satisfied I can switch to the pro lens.

However saying that the Rare Fresnel would be 330m and the Lense will be the 18", I get the following for my calculations using the Focal Calculator.

LCD Size: 19 Inches
Frensel Gap: 1 Inch or 25.4 mm
Frensel FL: 330 mm
Triplet FL: 550 mm
LCD Distance: 661.09
Screen Distance: 10.57
Screen: 100 Inches

Do this sound right ?

[Mikey p]

Not quite. The lens you're bidding on is a 18 inch F.L. 18x25.4=457mm.
So 457 is what you enter in for the triplet F.L., not 550.
This makes the lcd to triplet distance 546mm.
The best fresnel for this set up is the 3dlens.com 550mm.
So 550mm gets entered into the fresnel F.L.
Notice the fresnel F.L. is for the fresnel between the lcd and the triplet. The fresnel F.L. between the lcd and lamp is not important for figuring out the projectors focal calculations therefore it's not included.
Screen size is 100 inches diagonal.
The screen distance is 9 feet.

If you were to use the Lumenlab Pro triplet then things change a little. you would enter 500mm into the triplet F.L.
This makes lcd to triplet distance 598mm. The best fresnel for this setup is the LumenLab 650mm (which has been tested and found to be really 600mm)
Screen size is 100 inch diagonal.
screen distance is 9.8 feet.

With either setup if you're using a reflector then you need a 330mm fresnel on the lamp side.

[gssmind]

Ok now that answers a lot of questions about the calculator and also is starting to make a bit more sense.

Ok so if I get this right, then I have the following two options:

Withe the 18"
Triplet FL: 550 mm

Withe the Lumen Lab Pro Triplet
Triplet FL: 650 mm

[Mikey p]

Originally posted by gssmind
Ok now that answers a lot of questions about the calculator and also is starting to make a bit more sense.

Ok so if I get this right, then I have the following two options:

Withe the 18"
Triplet FL: 550 mm

Withe the Lumen Lab Pro Triplet
Triplet FL: 650 mm

With the 18 inch lens the triplet F.L. is 457mm and the matching fresnel is 550mm
Lumenlab triplet is 500mm F.L. and the matching fresnel is the Lumenlab 650mm( it really is a 600mm)

[gssmind]

Ok Finally I have some pics to share.

This is how I built my Frame.

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Some Part of the old monitor to be reused:



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Steel Frame and the plastic, in between which the LCD will be placed:



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Close up of the same pic:



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All of the pieces together:



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Marked on the outer frame where delicate LCD connectors are to be passed.
Hence I used a Drum Sander and chopped it off:


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The outer frame that goes in the front:



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Close up of the buttons, dono but I might reuse them later:



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Hence I take them off with a screw driver:


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Set of drill bits I got, including the two sets of different kind off screws:


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