Originally Posted by Uther
I'm still wondering if the black levels will be that much better. I understand you can vary the intensity of the laser, but think of the classic candle in a pitch black room image. The flame needs to be very bright, but the rest of the image should be nearly black, you can't do both very well by attenuating the intensity of the beam.
First, as Ohlson pointed out and my previous post showed a related example, it is about relative/local contrast.
Second, lasers are much more than just another kind of light source. They effectively have near zero etendue. This can be used to greatly help contrast in multiple ways. The most obvious of which is that the projection optics can go to higher F-numbers which will lead to higher contrast optics.
It also means that the illumination angles going to the microdisplay are tighter which will help contrast, this will be particularly important for LCOS devices due to the way the LC works. You may notice that the Sony SXRD has higher measured contrast (by reviewers not just Sony) when the Iris is stopped down; with a laser it is like the iris is stopped way down yet all the light gets through so the contrast goes up without having to stop down the iris.
Then as others have noted there is the ability to adjust the intensity of the laser with more control than with an iris and the additional ability to iris the colors individually (maybe some fun computations to make to have this work).
Now, if they are implementing the laser in a pulse fashion, where one pulse is reflected off of a corresponding mirror in the DMD, then you are talking better than CRT black levels, but the optics would have to be very precise and the pulse speed would have to be ridiculously fast, not to mention the need to realign the laser the to get the correct reflection path off of the DMD.
My guess is the former approach is the one being implemented - I just wonder what the maximum CR is that is attainable utilizing that method.
It doesn't work like this, they will spread the laser beam out to illuminat the whole array of mirrors. The better contrast will come from using higher F-number optics. The good news is that because the laser beam is spread out over 2-million pixels and not a tight focused beam, it is very safe for human vision.
For what it is worth (trying to quickly summarize some points I have made in other topics), I think it is very clear technically that LCOS stands much more to gain from Lasers than DLP does. Lasers have polarized light and color separated light which is good for 3-panel LCOS. But perhaps the biggest advantage is that while lasers can be pulse, most of them will output more light energy in a continous mode and thus are much more cost effective when use to illuminate 3 panels where LCOS devices are much more cost effective.
Per Ohlson's point earlier, it is a bit surprising that there has not been a LCOS based Laser announcement, but I would be very surprised if they did not hit the market in the same time frame as DLP and HTPS (Epson) laser based products.