DIY Rear Projection TV

[GreenApple123]

I know that this is a random post but it seems like everyone in here is really knowledgable about technology and theater compnents so I thought I post anyway.
I love my RPTV and recently the lamp blew out on it. I bought a new one from an online site I found called http://www.laptopsforless.com/rptvlamp and it works great. Has anyone else purchased replacement lamps for their RPTV before? Is it OK to do through an online company?

[cromaclear-crt]

Jrhiltion

James

Throughout this lonnnnnggggggggggg thread Ive noticed that you believe 'sandblasted glass until white' is the best method to make an RPTV screen but no one actually tried it.

Could you tell us what thickness or and type of glass is best...also the sand what guage should it be to achieve best results.


Thanks

[rcavictim]

Originally posted by cromaclear-crt
Jrhiltion

James

Throughout this lonnnnnggggggggggg thread Ive noticed that you believe 'sandblasted glass until white' is the best method to make an RPTV screen but no one actually tried it.

Could you tell us what thickness or and type of glass is best...also the sand what guage should it be to achieve best results.


Thanks

Sandblasted glass will work but it has a pretty wide light scattering pattern (wide angles of view) which will mean that it won`t be as bright to the viewer for any given brightness available from the projector as compared to engineered fresnel lens screen systems that increase brightness cleverly with directional gain.

The glass should be as thin as practical to close up the spacing of the double image you will get from the reflection of the unblasted surface. Project onto the blasted side. Ordinary beach sand works as well as commercial sandblasting sand. I cannot say which gives a superior result as i didn`t explore this very far while experimenting with it almost 20 years ago now.

[Isaack]

Hello,

I'm planning to create a screen made of 4-6 smaller panels and software to combine it into one big image. However, to get rid of the borders from each panel. I'm planning to use Rear Projection in a short distance, hence the post in this topic.

I've already acquired some plexi glass samples, off one is a small piece of RP dark plexi glass. I tried testing with a simple transparent sheet with a color image. However due to the lack of knowledge within this technique, I don't really know how to project a sharp image onto it. If I backlit it and keep it just up against the panel, the image becomes sharp and looks fine.

However if I keep sheet at a distance, the image becomes more blurry the farther away I pull the image. I suspect that I need a lense in between to like "focus", is this correct?
Would it be a fresnel ?

As I don't want to project each panel much bigger than they already are, I hope that it can be achieved with a very short focal length. I basically just need a few percentage more to project the images up against each other on the big RP panel seamlessly.

[chemlins]

Hi, ive tried the diffuser sheet from the backlight of an lcd and it works fine.There seems to be no hot spot , the image is very sharp and clear and the light is evenly distributed at a good brightness.Does anyone know where i could get large quantities of the sheet so that i could use it as my screen.THanks

[Tobias Claren]

Hello.

The foils often are from 3M.

What is the best well-known DIY rearpro solution?
Is there still nothing?

[Skital]

That 3M film is most likely the one used in Vikuiti's black rear projection screen. I have a rigid rear screen sample with the film on it. It is AWESOME. Too bad that a 95" version costs about $5,000 and even a 60" version costs more than a 65" HDTV.

The screen is basically a black absorbing layer on the back of a matte acrylic sheet with a thin diffusion layer on the back with millions of microspheres (glass beads) that redirect the light creating a bright, high contrast image with a wide viewing angle. The screen trumps every material I've tried; it's incredible.

I think I may have possibly found away to make a DIY versioin of the Vikuiti black rear projection screen, but it will cost at least $115 just to try out with experimenting. There is a clear paint with microsphere beads in it. I want to combine it with a matte/frosted clear paint and possibly transparent black dye and would like to try in layers too. A single layer would probably create the brightest picture though. My goal is to make a 10.5' x 5.9' rear projection tv with my commercial home theater projector

If anyone else is interested in this project and wants to contribute to help get this project off the ground asap sign up here and the cost of the materials can be split between everyone interested and the results (with pictures/screenshots) will be posted here. I don't think anyone wants to shell out $100 to try something that might work, so if anyone thinks this is a good idea and is interested in contributing let me know. I am willing to pay at least 20-25% of the cost myself if I have to.


Maybe there is someone here willing to shell out $100+ though himself to get the project running. If so, that is great too. The more contributors the less cost between everyone. Hopefully this has enough interest, because if it turns out to be as good or close to the vikuiti one could potentiall build upto a 10+ wide rear projection tv.

[Tobias Claren]

Someone guessed me from Röhm at the telephone that Degussa (competitor!) has a cheaper solution. Not the High end stage of this Röhm screen, but very well for private. Not much “more badly”.

The Degussa back projection screen contains “embedded micro lenses”.

[TvWatcher]

I'm a new member. It's so really fun and rewarding to find such dedicated people. The site is fast and easy to post to and the intelligence level is on par with the best of the best. : )

I belong to probably 30 forums. This one will be fun to visit and contribute to. My background is onlocation sound recording for symphonic orchestra. I stopped when digital came along due to the cost and I had to go to college.

Now I'm making portable battery packs for fun and friends and enjoying retirement at 54 next year.

As always if anyone is wanting any kind of help with electronics, batteries, sciences of any kind, chemisty,
or research help I'm glad to assist. Just PM me and ask away!
Andre

[jvisaria]

Hey folks i used to be all over this DIY projector business... anyhow I just dug up a brand new Delta IV lens in my old boxes... are you guys still using these?

If anyone wants it just PM me, I'll let it go for cheap I just don't want to throw it out.