Hello, I found this fourm about two weeks ago and am very interested in building my own projector. This is also my first post on this fourm. I've been reading many posts the past two weeks and have been impressed with everyones results. I hope I can do as well.

I'm still in the design stage for my projector. I want to use the Sharp 15" WUXGA LCD. I will be using it in my bedroom which is a little small for a projector. I plan on putting it on a wall shelf above my bed where I currently have my rear center surround speaker. The opposite wall has my 27" Sony as well as my front speakers, HTPC, satellite receivers, CD and DVD changers, ect... After getting rid of my 27" I would only have enough blank wall for about a 4-5 foot diagonal image. The distance from the projector to the wall would be about 8-9 feet. I'm planning for a vertical design with a mirror and lens at the bottom half of the box.

What I need advice on is which type of lens, pro or standard, to use? I was thinking about getting a pro lens. I've used the focal calc. program to try to estimate the lengths and distances of the varius componets of the projector but I'm not sure how much a 45 degree mirror changes the length and spacings.

What size mirror would I need? I would need one the same size as the LCD I would think? Some of the drawings I've seen show the light path comming from the LCD focusing at a smaller area on the mirror. With the mirror at a 45 degree angle directly behind the lens I might think the lens would need to be further away from the mirror to capture all the reflection. I tried the focal calculator but wasn't sure about lens and LCD spacing with a mirror added.

One thing that concerns me about the Sharp LCD that it's only capable of 262K colors. Is that normal for all LCDs? I see that it can do 16.8 million colors with dithering but doesn't that degrade the image? Can anyone comment on this? I would like to use a new WUXGA LCD capable of 24 bit color natively. Do any exist that we can use?

Thanks in advance for your time and help.

I guess no one has any answers to my questions.

I have done some more reading and found some answers to my mirror questions. I'm still not sure about using a pro lens or not. I still don't know about the WUXGA LCD using 262k colors, if thats normal for all LCDs and what effect dithering the colors has on the image quality.

Welcome to LL Matrix Man.

The pro lens is probably what you'll need. It has a longer throw so your pj won't have to be so close to the screen to make a smaller image.
I use the standard lens with a 17 inch lcd. The lens is 8ft 4 inches from the screen and it produces a 4.5 ft X 9 ft widescreen picture.
In the 4:3 standard picture it is about 9 ft high X 8 ft wide (estimated). The picture quality using the standard lens with the 17in lcd isn't very good but the widescreen is awesome.
My pj is a straight design hanging from the ceiling for now.
ps.blue or red pill [ I took both and landed here ]

I think joechevy2000(or it might be joe2000chevy (use the search on members names) has a great vertical gide with measurements, LL sells a mirror for this use, it actually has to be bigger than the lcd because its angled at forty-five degrees...as for the 262K colors, I THINK that is normal for widescreens that size, many of the standard 15" Lcds also use dithering and it seems to be no problem(though obviously it would be nicer to be native) .... I saw a discussion somewhere about this and no-one knew of a true 24 bit widescreen I think...

I hadn't thought about needing a larger mirror for the 45 degree angle, but I think you are right.

I think I'll go ahead with the WUXGA LCD anyway, I haven't found anything else that comes as close to what I want. Now I just need to find a new one with a driver board. I saw that there was a group buy not to long ago for the LCD with driver, I have no idea when there will be another one. It also appears the pro lens isn't out yet so I will have to wait on that too. Looks like it will be a long while before I can get the parts together.

I've done some measurement estimation in Autocad. To use the LCD I'm planning for and the pro lens kit when it comes out I'll need to trim a few inches off either side of the fresnes lens, to keep the width of the box small. I'm just planning to use one fresnel lense behind the LCD, hopfully that will work ok. How important is it to keep the concentric circles that make up the lens centered when used to spread out the back light? I would think I would need to cut equal ammounts off either side.

I saw this thread http://www.lumenlab.com/forums/index.php?showtopic=9182

Surplus shed is selling used DLP projectors. I ordered one, it just came today. Although I haven't build my first projector yet I now have some interesting optics to experiment with. I haven't dug into it to deep yet, the unit contains no light bulb but it has a 1.25" reflector, maybe a cold reflector?, probably a hot mirror, what looks like a dichroic filter wheel. Of course it uses a folded design with the DMM as the folding mirror.

Interesting stuff to play with until I can gather the componets I need to build my own.

Since my last post I have tracked down and received a Sharp 15.4" WUXGA LCD. Today my pro lenses and mirrors arrived with my light kit. All I need now is the driver board for the LCD. I've got to get designing now I have most of the componets to measure by. The pro lens, light bulb, and mogul are a lot bigger in person than than I thought they would be. The pro lens is very impressive, it has a lot of mass.

I've been working on my first design. I've been sketching out the parts placement and spacings. I've put the 220mm fresnel about 220mm from the center of the bulb, I'm not sure about the 650mm fresnel. I currently have it between the 220mm fresnel and the LCD. Do I need to put it after the LCD? I'd rather not, I don't wan't to degrade the image quality any more than I have to.

I've highlighted the spacing distances I'm not sure about in red. The distance from the pro reflector to the bulb, but primarly the distance from the 650mm fresnel and LCD to the FS mirror, as well as the distance from the center of the FS mirror to the center of the pro lens.

Can any of you more experienced builders provide some direction?

ThanksClick to view attachment

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Welcome Matrix Man

I found these forums a few weeks ago myself and now am building my projector, I know that you will find the project interesting. So good luck with it


Cheers

I've gathered my materials and started construction of my first projector.

http://new.lumenlab.com/forums/index.php?showtopic=11921