I've decided to take a shot at designing a folded 17" projector. I used Okflyboy's design as a starting model and modified it to fit a 17". The upper portion of the projector is designed to slip pass the lower portion to allow for tweeking. I have the field lens mounted in a frame that is allowed to pivot for keystoning.

First off, how whacked are my dimension on the placement of all the lens' and LCD (Joe)?

Am I going to have heating problems? I figured that if I sealed off the light box from the LCD and placed a fan in the top of the light box that could handle the heat. I figured I might be able to fit a slim line blower in above the lexan if I need more cooling.

This is a rough first design. All comments are welcome, especailly from the gurus.

Neat design. Why so much extra space behind the reflector and around the fresnels?

Thanks Vukick. The space around the reflector could be reduced, just thought I'd leave some room for adjustments. The field fresnel has room to pivot for keystoning. Plus all the lens' will be framed. I left the lens their original size just in case I want to upgrade to a 19" screen at some point.

Does anybody know if my distances between the lcd, fresnel, triplex, mirror look correct?

Distance between panel and miror is 330mm. Distance between mirror and lens is 292mm. 330 + 292 = 622mm. Brain gives a guideline of 572mm for the Pro lens.

Here: Simple Projector


You also have 54mm between LCD and Field lens. I thought this was still supposed to be 20mm. I haven't seen any changes on this with the new field lens. This should be true even for keystoning. (One end remains at 20, the other swings out)

Also between collector and LCD you have 23.8 mm and I think this is still supposed to be 11mm (or 13? I forget which).

BTW, please post a new design layout when you get the numbers right. You are doing my work for me.

Zendance, Thanks for the info. I changed to panel to lens distance. I changed the condensor to LCD back to 15mm. As for the LCD to collector distance I need the room to be able to adjust to 10 degrees of keystoning. Somewhere, I can't remember where, I thought Brain said that you could move that fresnel about 2" away from the LCD to allow for the swing.

I'll be happy to post all my drawings when they are more finalized. I hope to have a fairly complete set of shop drawings to make the building process easier. Especially for new members.

2" is too far, try to keep it as close to 15mm as you can.

Is 1-1/8" too far? Otherwise I don't have a lot of pivot room left.

Should be ok.

Any new updates on this drawing? Now that the new lenses are out, I am ready to start building. This is the design I have decided to go with instead of the long version. This folded version will fit into my room better. I just want to make sure that the overall dimensions of the box are correct before I start to cut. I am not much worried about the placement of the parts inside. I can move those if needed. I just can't add wood back if I cut to short

To be honest, I'm considering revising my design and going with a single mirror box ala Thomas:

http://www.lumenlab.com/forums/index.php?s...indpost&p=31288

Because I just don't have time to get too freaky and I really want a 17" projector. I've been thinking hard on the 8% loss PER mirror and wondering if it's worth to shave a few more inches.

wondering if SOME more shaving can be accomplished, with Thomas's design having an additional mirror before the lcd from the lightbox......
that might shave some length
I was really looking forward to your 3 mirror design, Brain, as it would allow for a shorter design, if on a table, or better yet, hanging from the ceiling.............. with a 17" monitor, and the lcd straight up, it would be like 16-17" tall, and that definately catches the eye when hanging from the ceiling - wife issue there -
Ricoks

Actually my Dell, with circuitry and frame is only 12" tall. If I use .5" ply my total height will be 13" which I don't feel is bad.

Have you already buit the PJ with the dell Brain?

I have not.

I am planning on constructing a simple, single-folded 17" widescreen. The mirror can be much smaller than the lcd. In order to calculate the size of mirror in the folded design, I need the angle at which the image leaves the focus fresnel. What degree is this angle? Thanks all.

About 13.3º

Brain you sed about? How much play is there +/- 1º (more/less)?

Brain is there an option for a brighter bulb to cancel out the 8% loss per mirror?

Not really sure, I'll ty to find out.

There are brighter lamps but they tend to be wrong for this projector. The hunt is still on.

Wrong in what way? What is the down side that is discouraging you?

(Sorry, just trying to understand more about projector design.)

Expense, life, size mostly.