I have read about this new Sony screen that is black and is supposed to do wonders for contrast. Does anyone know of a way to DIY this sort of screen? I need all the contrast ratio I can get.
J
J
what about using a highly reflective material...like shiney gift wrap and place a thin black translucent "wedding dress" type material over it? Wouldnt the refective material refect the white light well while the black material makes the darks look darker? Just a thought.
I'd guess that it's going to be very difficult to DIY something like this. The idea behind the screen is that it is highly reflective only for the 3 specific wavelengths that make up a projected RGB image, and is otherwise absorptive. Since ambient light is typically very broad-spectrum, it will contain relatively small energy in any single narrow band like the ones that are reflected by the screen, thus giving the high contrast ratio.
I don't know how Sony actually does this, but typically this type of wavelength sensitivity is a thin-film application - I don't think 'normal' chromatic filters have anywhere near this type of selectivity.
I don't know how Sony actually does this, but typically this type of wavelength sensitivity is a thin-film application - I don't think 'normal' chromatic filters have anywhere near this type of selectivity.
Sony screen
Hey where did you see this new screen, sounds intresting and would look better in an average room.
Hey where did you see this new screen, sounds intresting and would look better in an average room.
just a thought;
as lcd beamed light is polarized (through the technique an LC-Display works) what about the possibilty, that this filter on the screen is some kind of polarizing filter again...
as ambient light is mainly not polarized (this is visible through an LCD; cause it is mainly dark) this filter on the screen only lets the beamed (polarized) light through onto an reflective material , which is passed back to the viewer... so the ambient light is held back an the beamed light shines back so th econtrast would be awesome...
sorry for my poor english; i hope this is understandable to those, who know how an LCD works...
just a thought...
as lcd beamed light is polarized (through the technique an LC-Display works) what about the possibilty, that this filter on the screen is some kind of polarizing filter again...
as ambient light is mainly not polarized (this is visible through an LCD; cause it is mainly dark) this filter on the screen only lets the beamed (polarized) light through onto an reflective material , which is passed back to the viewer... so the ambient light is held back an the beamed light shines back so th econtrast would be awesome...
sorry for my poor english; i hope this is understandable to those, who know how an LCD works...
just a thought...
While messing with the polarization can do some amazing stuff (like one of the best means of making a multicolor true stereoscopic screen[though you still need classes]), I don't think that's what they're doing. They're using optical bandpass / notch filters. They have to have some specified means of coating the screen w/ 3 pigments that only reflect very narrow bands of light, and transmit (are transparent to) most of the rest of the visible spectrum.
The closest I've seen to the idea is the Light Fusion screen, which involves painting + sanding down three colored coats over an acrylic mirror. Thiswas at one point the crème de le crème of the AVSForum DIY screens section - one of its supporters who does HT installations for a living bragged that it beat the several thousand dollar Stewart screens being exhibitted at a trade show.
The Fusion is very expensive in DIY terms, mostly in the cost of the mirror/shipping + the labor involved. I doubt that you'll see anything DIYed that works on the exact same principle as the Sony product, though, and it costs about $2000 last I heard.
The closest I've seen to the idea is the Light Fusion screen, which involves painting + sanding down three colored coats over an acrylic mirror. Thiswas at one point the crème de le crème of the AVSForum DIY screens section - one of its supporters who does HT installations for a living bragged that it beat the several thousand dollar Stewart screens being exhibitted at a trade show.
The Fusion is very expensive in DIY terms, mostly in the cost of the mirror/shipping + the labor involved. I doubt that you'll see anything DIYed that works on the exact same principle as the Sony product, though, and it costs about $2000 last I heard.
For those who haven't seen...
This thing is capable of excellent blacks and contrast even in a well-lit room:
This thing is capable of excellent blacks and contrast even in a well-lit room:
An externally hosted image should be here but it was not working when we last tested it.
Unfortunately, that price is for an 80" diagonal screen. OUCH! Gotta be some inexpensive DIY way to do this...Squalish said:
Is there any material that can absorb light between 490 to 530nm while transmitting other wavelengths? I was thinking along the lines of specialty theater gels. This would look like a yellow gel I believe.
If one could find that, and another that absorbed 560 to 615nm, one could stick a sheet /coat of each of those in front of the projection screen. This should make the blacks blacker (absorbing ~40% of unwanted ambient light) without reducing the R G or B from the LCD.
Actually... I guess it would make the blacks sort of Purplish (guess)? Two more materials absorbing <475 and >650nm would be needed to get closer to Black. Maybe the colors would just get totally out of whack.... there's probably a good reason why Sony has a patent on their screen...
Here are some spectral charts:
http://www.sewanee.edu/chem/Chem&Art/Detail_Pages/Projects_1998/pigment&light.htm
including a yellow gel... but it looks like that one is far too wideband.
I also found an interesting explanation at http://library.thinkquest.org/27066/color/nlchanges.html.
If one could find that, and another that absorbed 560 to 615nm, one could stick a sheet /coat of each of those in front of the projection screen. This should make the blacks blacker (absorbing ~40% of unwanted ambient light) without reducing the R G or B from the LCD.
Actually... I guess it would make the blacks sort of Purplish (guess)? Two more materials absorbing <475 and >650nm would be needed to get closer to Black. Maybe the colors would just get totally out of whack.... there's probably a good reason why Sony has a patent on their screen...
Here are some spectral charts:
http://www.sewanee.edu/chem/Chem&Art/Detail_Pages/Projects_1998/pigment&light.htm
including a yellow gel... but it looks like that one is far too wideband.
I also found an interesting explanation at http://library.thinkquest.org/27066/color/nlchanges.html.
Never underestimate the creativity of a DIYer!
Way to go, charlie10! Glad someone is thinking about this. Even if the ideas don't work, they may well lead to something that does. Personally, I don't have enough knowledge of optics, etc. to contribute much. If anything, I'll take the low-tech approach...
I'm thinking about a glossy black background (to - in theory - reinforce the areas of projected black/gray in high ambient light conditions) covered by a layer of... not sure what this fabric is called, but it's a sheer fabric - hold it up and you can see right through it, but place it on a surface and it has a sheen to it. Moire may be a problem, I'm not sure. If so, is there a way to deal with that? Anyway, due to the sheen, I'm thinking this fabric may have a decent gain to it. Not sure what effect the textured surface might have on image focus and/or whether the viewing cone might be positively or negatively effected, but the fabric I'm thinking of is pretty flat - not much texture to it. If the projection surface needed to be smoothed out, I'm guessing you could actually put a coat or two of some kind of clear finish (gloss? satin?) which would have the added effect of adhering it to the glossy black back surface.
Just thinking out loud here. Anyway, it wouldn't cost much to fab up a sample piece. (But first I have to build a projector!)
Way to go, charlie10! Glad someone is thinking about this. Even if the ideas don't work, they may well lead to something that does. Personally, I don't have enough knowledge of optics, etc. to contribute much. If anything, I'll take the low-tech approach...
I'm thinking about a glossy black background (to - in theory - reinforce the areas of projected black/gray in high ambient light conditions) covered by a layer of... not sure what this fabric is called, but it's a sheer fabric - hold it up and you can see right through it, but place it on a surface and it has a sheen to it. Moire may be a problem, I'm not sure. If so, is there a way to deal with that? Anyway, due to the sheen, I'm thinking this fabric may have a decent gain to it. Not sure what effect the textured surface might have on image focus and/or whether the viewing cone might be positively or negatively effected, but the fabric I'm thinking of is pretty flat - not much texture to it. If the projection surface needed to be smoothed out, I'm guessing you could actually put a coat or two of some kind of clear finish (gloss? satin?) which would have the added effect of adhering it to the glossy black back surface.
Just thinking out loud here. Anyway, it wouldn't cost much to fab up a sample piece. (But first I have to build a projector!)
I wonder if this screen is just some kind of large diffraction grating with small areas tuned to each wavelength which would represent pixels for each pixel on the LCD.
Diffraction gratings are selective in the wavelength of light that they diffract. In theory you could design a blown up replica of the LCD pixel geometry and create a small diffraction patch tuned to the exact light wavelength at the subpixel location.
The upper areas could be coated with a black non reflective coating and the lower areas made highly reflective. In this case the lower areas would diffract light at only the proper wavelength and normal incedent light would be mostly absorbed.
Maybe?
If this is the case it would be the perfect screen because it would basically absorb all ambient light and diffract only the wavelengths designed for. Also, the diffraction is perfect because it basically acts diffusive at only the diffracted wavelengths.
The hard part about making this would be the mold because it would require micro machining or photo lythography etching. Once a metal stamps was made you could just stamp out the screens in warmed up acyrlic much like a fresnel lens is made only on a larger scale.
Hezz
Diffraction gratings are selective in the wavelength of light that they diffract. In theory you could design a blown up replica of the LCD pixel geometry and create a small diffraction patch tuned to the exact light wavelength at the subpixel location.
The upper areas could be coated with a black non reflective coating and the lower areas made highly reflective. In this case the lower areas would diffract light at only the proper wavelength and normal incedent light would be mostly absorbed.
Maybe?
If this is the case it would be the perfect screen because it would basically absorb all ambient light and diffract only the wavelengths designed for. Also, the diffraction is perfect because it basically acts diffusive at only the diffracted wavelengths.
The hard part about making this would be the mold because it would require micro machining or photo lythography etching. Once a metal stamps was made you could just stamp out the screens in warmed up acyrlic much like a fresnel lens is made only on a larger scale.
Hezz
I think that it would be made with dichroic, simular principal as the diffraction grating though.
DJ
Ok guys,
I have read the patent and it describes four different ways that the screen can be made but all of the amount to some kind of triple bandpass filter.
My first idea on how it was made would be too difficult and expensive to impliment, plus it wouldn't work for more than one aspect ratio.
In the patent the filter is constructed of four layers of polymer films which either selectively reflect the bandbass wavelengths or absorb the non bandpass wavelengths.
The materials are just transperant polymer films with colorants or dyes added which either reflect of absorb the needed frequencies.
To make a screen filter on top of a regular diffusive screen you would need a transmissive filter. Or if you had a reflective filter you could dispense with anything but the filter layer except a backing to hold it together and absorb more light.
Hezz
I have read the patent and it describes four different ways that the screen can be made but all of the amount to some kind of triple bandpass filter.
My first idea on how it was made would be too difficult and expensive to impliment, plus it wouldn't work for more than one aspect ratio.
In the patent the filter is constructed of four layers of polymer films which either selectively reflect the bandbass wavelengths or absorb the non bandpass wavelengths.
The materials are just transperant polymer films with colorants or dyes added which either reflect of absorb the needed frequencies.
To make a screen filter on top of a regular diffusive screen you would need a transmissive filter. Or if you had a reflective filter you could dispense with anything but the filter layer except a backing to hold it together and absorb more light.
Hezz
Ok done reading the patent. Hezz is right looks like it boils down to an expensive triple-bandpass filter.
Not sure about diy potential here. The patent is totally vague on how exactly to construct a triple bandpass filter, but as an example it explains one way to build a double bandpass filter. It uses refraction at a micro scale. All you have to do is put down 13 layers of 3 materials (gold, quartz, and titanium dioxide) in the right order. Each layer is a thin film with an exact thickness, ie. layer 8 is 270.66nm of Ti02, and layer 9 is 4.16nm of gold.
Unfortunately, I have to say I used up all my Rust-o-leum #3166 "Elemental Gold, Thin Spray" last week re-surfacing my personal bling bling collection. (A guy has got to have his Priorities straight!)
Speaking of bling bling, we might be to take the filter film off of one of their triple bandpass rear projection screens (transmissive), cut it up into little rectangles, and make em into eyeglasses. Then just wear a pair of those shades around whenever we want to watch an RGB digital projection with the lights on. Let's see if a 160"x90" Sony RP blackscreen is $7000, and eyeglasses are 2x1"x2", that's about 3600 pairs of shades at 2 bucks each. Or 5 bucks for the Oakley style 😎
who is up for a group buy? hehe 😀
Not sure about diy potential here. The patent is totally vague on how exactly to construct a triple bandpass filter, but as an example it explains one way to build a double bandpass filter. It uses refraction at a micro scale. All you have to do is put down 13 layers of 3 materials (gold, quartz, and titanium dioxide) in the right order. Each layer is a thin film with an exact thickness, ie. layer 8 is 270.66nm of Ti02, and layer 9 is 4.16nm of gold.
Unfortunately, I have to say I used up all my Rust-o-leum #3166 "Elemental Gold, Thin Spray" last week re-surfacing my personal bling bling collection. (A guy has got to have his Priorities straight!)
Speaking of bling bling, we might be to take the filter film off of one of their triple bandpass rear projection screens (transmissive), cut it up into little rectangles, and make em into eyeglasses. Then just wear a pair of those shades around whenever we want to watch an RGB digital projection with the lights on. Let's see if a 160"x90" Sony RP blackscreen is $7000, and eyeglasses are 2x1"x2", that's about 3600 pairs of shades at 2 bucks each. Or 5 bucks for the Oakley style 😎
who is up for a group buy? hehe 😀
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I think it would be possible for us to build one of these screens in a different manner if we had someone with sufficient knowledge on what colorants to add for each of the four films to make the filters and the desired cut off ranges. One filter must block or absorb all light below the lowest of the three frequencies. The next must block or absorb all light above the highest of the three frequencies. The next two filters must let all light pass except in the regions between the three wavelength zones. In this way you can create a filter with three distinct narrow frequency notches that pass light only at those frequencies.
We would not use films because these are likely to be custom made and expensive in large sheets. In reality the polymer film is just a carrier for the colorants and or the minerals that do the filtering. It seems to me that if you know the right things to add to each filter you could mix your own with a clear laquer or polyuethane and spray each layer on a diffusive screen building up the four successive layers as you go.
Hezz
We would not use films because these are likely to be custom made and expensive in large sheets. In reality the polymer film is just a carrier for the colorants and or the minerals that do the filtering. It seems to me that if you know the right things to add to each filter you could mix your own with a clear laquer or polyuethane and spray each layer on a diffusive screen building up the four successive layers as you go.
Hezz
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