Visiting bTendo, makers of Laser-based pico projector modules

bTendo is an Israeli startup company, working on laser-based pico projector modules. They were kind enough to invite me to a visit. I met with Gilles Rapp (COO) and Elan Roth (VP Biz Dev & Marketing).

A little bit about bTendo

bTendo is a small company (around 15 employees). They have designed and developed a MEMS-based scanning laser pico projector. This design allows them to build a very small projection module - only 6.5mm in height. This is much smaller than what's available today with DLP or LCoS modules (which are more than double that height, today).



bTendo projector modulebTendo projector module

bTendo does not aim to make an actual projector, but to sell their projection module to other companies that make the projectors, or to companies who will embed it in their mobile devices (such as mobile phones or digital cameras).

Back in 2007, bTendo raised 7M$ from a couple of VCs. Now they are in the midst of the 2nd round of financing. This should allow them to finish the module and start producing and selling it.

You can visit bTendo's web site to learn more.

bTendo's laser based projector technology

With laser based projectors, the idea is to have 3 laser sources (Red, Green, Blue), shape them into one 'beam' using some optics, and then use a mirror to direct the beams to the right 'pixel'. The projector displays one pixel at a time, and if you do this quickly enough, you won't notice it (bTendo's projector has a 60Hz refresh rate, and you do not notice any flicker at all).

bTendo's design actually uses 2 electrostatic MEMS mirrors - one allows for horizontal movement, and the other for vertical. They claim that this design allowed them to create a very small module, and a very effective one, as well. In fact this two-mirror design is the heart of their IP.

The whole volume of their module is less than 5cc. This is also the thinnest module around, like I said before - only 6.5mm in height, and they are actually working on making it even thinner. bTendo's design supports resolutions up to SVGA (800x600), targets 15Lm brightness as well as power efficiency of 10L/w. bTendo demonstrated to me a full color, WVGA (848X480 pixels) prototype,  generating still images as well as various type of video content.

Laser based projectors Vs DLP / LCOS

Laser based projectors have several advantages compared to DLP or LCoS technologies:

  • Smaller size
  • Brighter colors
  • The picture is always focused. This is really cool. You can see in the photos that it's possible to project at variable distances and onto curved surfaces without the need to keep turning a focus dial...
  • Lasers are more efficient. "We control each pixel on the display. That means that black pixels do not require any power. To display an almost-black photo will require almost no power." bTendo suggests that projectors should have an 'inverse' mode, so that documents will appear as white text over black background to conserve power. This is also true for OLEDs displays, by the way.

Check out the following photos showing the difference between bTendo's projector and an LCoS one (a commercially available pico projector). The laser based projector is on the right:

bTendo laser projector vs an LCoS projector photo bTendo laser projector vs an LCoS projector photo bTendo laser projector vs an LCoS projector photo

Here are more photos showing how a laser projector can be used to project on curved surfaces. No need for a focus!

bTendo laser projector on curved surface photo bTendo laser projector on curved surface photo bTendo laser projector on curved surface photo

The biggest disadvantage of laser based projectors is the 'speckle'. Speckle is a random intensity pattern produced by the mutual interference of a set of wavefronts. It basically means that there are shiny black dots visible all over the image, (it's mostly on static images, videos suffer much less). You can see the speckle dots with any laser-pointer as well. The guys at bTendo says that some people are more sensitive to this effect. At first it is annoying, but you get used to it quickly. The images are somewhat less 'soft' than the LCoS ones because of that. In any case, bTendo is working on several technologies to reduce the speckle, to a degree it would most likely no be bothersome to most people.

Here are a couple of videos showing the laser projector on a curved surface, and how it fares next to an LCoS ones. Notice that the laser projector, running at 60Hz seems to 'flicker' on the videos, but it's not like that in the real world of course.

How bTendo sees the pico projector market

The guys at bTendo think that the pico projectors have two roles. First of all, they can enhance the user experience. But they think that the real promise is the sharing of information - the ability to project large images or videos so that others can see as well. Evidently research has shown that people are very interested in sharing their photos and videos, and will be happy to do so on the go.

Most pico projectors will probably be embedded in other devices - mobile phones, A/V players, game players, digital cameras and laptops. But there will also be 'dedicated' pico projectors. bTendo envisions them as very small gadgets. Much smaller than today's crop of standalone pico projectors...

I wish bTendo good luck, and hopefully we'll see some projectors who use their technology soon!


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