Sony and Sumitomo

Sorry for being away from the blog so long.  I had two big “consulting gigs” come in one right after the other and I have been working virtually non-stop for the last 6 weeks.  There has been a lot of news come in that period in the area of displays and lasers and I will try and get caught up on some of it.

Today I would like to talk about Sony and Sumitomo announcement of a 530nm 100mW Green laser with 8% efficiency.  At least on the surface, this appears to be a big improvement what Soraa, Osram, and Nichia have announced to date.   But the big question is whether this really changes anything for pico projectors?

Semiconductor laser diode/True green laser emitting

Sumitomo and Sony 530nm Direct Green Laser Diode

Sony was much quieter than Soraa, OSRAM and Nichia but it certainly should have been expected since they developed blue lasers for blue ray (see for example from 2007 “Sony’s Blue Laser Diodes Down to $8 – PS3 and BD Player Price Cuts Soon?”).  Sumitomo had announce they were working on green laser materials back in 2010 but they were not known as a maker of laser diode end products and were thought to be a material supplier (to Sony as it turns out).

Another company to watch would be Opnext who is a leader in red lasers and announced a blue laser diode back in January 2011. All the green laser diode developments I know of came from “stretching” their blue laser developments to get green.

Certainly the Sony-Sumitomo device looks on the spec’s to be significantly better than other companies’ prior announcements with a 100mW, 530nm wavelength (huge improvement over the others), and 8% efficiency.  When you factor in the luminous efficiency at 530nm, they appear to have about double the lumens/Watt of any other green laser announcement I have seen.

Something else to consider, Sony has long been a manufacture of LCOS devices so I would suspect (I have no inside knowledge) that Sony would be looking to couple this laser with their LCOS developments.  They also have the ability to make some very small pixels from their in high resolution LCOS devices.  But the question is whether they and support field sequential color which it necessary for making small embeddable devices.  It should be noted that Sony has a line of  embedded pico projectors in video cameras that use TI’s DLP®

With all this activity and the seeming much improved spec’s from Sony-Sumitomo does this change everything and will laser projectors soon be everywhere?  Unfortunately, I don’t see this as changing things much, at least in the next year few years.

Now the bad news and just based on what they have said.  A 100mW 530nm green laser only supports about a 20 lumen projector which is pretty dim except for a pretty dark room or a very small image. A projector using an 8% WPE green laser probably does not have net an efficiency advantage (after factoring in all the pro’s and con’s) over a good LED projector with at 20 lumens.  While this might have been an interesting product a couple of years ago, the market has mostly moved on to higher lumen projectors.

And then we have to some questions that were not in the release.  Such as how far away is the Sony-Sumitomo green laser diode is from being a product and how much will it cost. Today a green LED to support a 20 lumen projector probably costs about $2. I think there is a serious question as to whether a ~20 lumen project has a value proposition today even if the lasers were inexpensive by the time you factor in the rest of the projector cost.

My bottom line is that it looks like Sony and Sumitomo have made some great technical progress, but it is does not appear to be enough to have a seriously competitive volume product in the market any time soon.    Anyway, that is the way I see it,

Karl

3 comments

  1. Paul Benz says:

    yes, you’re right, provided that a given area must be illuminated with the 20 lumen.
    But if the LED has to backlight an LCD projector, then most of the light is lost, rsp, absorbed in the LCD.
    In a laser projector the entire light intensity of each laser is projected (with the scanner mirrors) to the desired point, which of course appears much brighter.
    Paul

    • admin says:

      Actually, with LCOS only a small percentage of the light is absorbed in the liquid crystal. Usually the mirror itself is more reflective than a MEMs mirror (better surface and flatter mirror characteristics because it is planer and does no move). The net lost of reflection+LC is similar to that of a MEMs mirror alone. The big issue with LED illumination is that light is lost due to etendue and polarization of light and lasers help LCOS tremendously on both accounts since lasers have near zero etendue and polarized light. LCOS projectors don’t use lasers today because they are simply not cost effective and they have an alternative.

      Several of my posts address some of the efficiency problems with laser beam scanning (see the post on “Laser Beam Scanning“), among the posts you might want to look at is http://www.kguttag.com/2012/02/01/answering-questions-on-laser-with-lcos-and-lbs/ and in particular the answer to Q7.

      Many of the efficiency problems with laser beam scanning occur in what it takes to drive the laser beam. The laser beam itself has to be analog modulated at high speed and this is power-wise inefficient. In addition to controlling each pixel, the beam has to be modulated to compensate for the high variable scanning process. The beam goes from near zero speed left or right edge of a scan like (and low beam output) to its maximum speed near the center of the scan line. Laser beam scanning projectors are much less efficient today and will likely continue to be less inefficient due to the inherent issues with LBS.

  2. I really had been hunting for tips for my own blog site and uncovered your own article, “Karl Guttag
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