# DIY TV? Classic projector style?



## demon2091tb (May 30, 2005)

In my head dosent seem toooo complicated.....picture this.

Large projection styled TV similar to the floor standers.

Items needed?
-some type of material for the screen that translates through very cleanly.
-Lens to magnify image to specific size, and so and so distance.
-CPU monitor, that can work with basic source inputs, VERY high resolution image to transfer through lens and onto material, for HD material.
-Light sealed enclosure to house everything.

Not sure what the costs of something like this nor where to find anything, but though that it would just be something cool to explore a little bit, and see if its even theoretically possible, or affordable, and what the best picture, size, etc is doable..........

I know projectors in the diy area are doable, but never come across a diy tv similar to this. Is DIY hd even doable?

Image would need to be flipped to correct itself and become the negative on the positive screen, but depending on screen size, lens size wouldn't need to be that large as long as it can capture the whole image....

I also know nothing of optics but am looking into it, lens distaces, etc. If i can find a lens the same size of the screen, that would expand a 15" screen 4x, up to a 60" image over a distance of 2ft, with a lens 4" away from the back screen.

I know its doable......i just need some direction. This is mainly just an exploration...


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## Spasticteapot (Mar 5, 2007)

demon2091tb said:


> In my head dosent seem toooo complicated.....picture this.
> 
> Large projection styled TV similar to the floor standers.
> 
> ...




It won't work. 

When you increase the size of a computer monitor from 15" to 60", you only have one-sixteenth the brightness. Once you calculate reflective losses, it's closer to 1/25 the original brightness of the LCD.

However, if you remove the LCD panel from its backlight and put a great big HID lamp behind it, you can build a nifty projector indeed.

http://lumenlab.com/

I've got a 15" LCD screen, stripped and prepared for use in a projector, in my (now ancient) F/S/T thread. Doing it yourself is a major pain - quite a lot of LCDs are sealed, making it impossible.


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## demon2091tb (May 30, 2005)

Well good to know the possible short comings of a design.

Sufficient brightness for lighting.


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## Spasticteapot (Mar 5, 2007)

demon2091tb said:


> Well good to know the possible short comings of a design.
> 
> Sufficient brightness for lighting.


An LCD works like a projector slide - it does not actually make light, but instead prevents varying amounts of red, blue, and green from passing through it. Behind every LCD is a set of tiny flourescent lamps and a diffuser panel. 

By removing the LCD (which is actually transparent when set to display white) and placing a massively powerful lamp behind it, you can increase the brightness by orders of magnitude.


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## demon2091tb (May 30, 2005)

How many lumens are we talking for a HD based resolution and brightness, for accurate whites and clean blacks, with high contrast.

I know HID's are around 10k, which is comparable to the sun within 4-5ft. But they get very hot.


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## badlieu (Jul 13, 2005)

http://www.engadget.com/2006/12/13/how-to-hd-projector-wrap-up-and-review-aka-part-7/

That's the build summary post - build parts 1-6 are linked up top on that page.

Their conclusion (build was 18 months ago so I'm sure some prices have dropped a bit) -


Engadget said:


> Our total cost was about $850 in parts (including long DVI and VGA cables) and around 60 to 80 hours of work. In other words, worth it probably only to few of you. Although, if we hadn't been writing it up, we probably could have finished it up quite a bit faster.
> 
> The final word on the DIY HD Projector: we'll give it a moderate rating. The high resolution produces excellent detail. The slight hot spotting in the middle might be mitigated by a bit of tweaking. (We hear that some DIY screen paint solutions work quite well.) Thanks to the large LCD surface, the screen door effect isn't noticeable 95% of the time. For cost effectiveness, you might seriously consider going with a smaller LCD and less expensive lenses. Considering the quality we've gotten, if you can keep the cost under $600, you're still getting a hell of a deal.


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