We see the world in three dimensions. Naturally, it would be desirable to see all kinds of images in three dimensions. This is one of those things in science and technology that’s relatively easy to describe, has many ways to accomplish, and has proven to be very difficult to get right. I’ve mentioned this before in connection with 3-D movies, which thanks to James Cameron’s Avatar, are having their third or fourth renaissance. The problem, as has always been the case, is that 3-D movies require special glasses. The glasses are a pain in the retinal nerve. Few people like to wear them and they make some people dizzy.
So what? This is a fair question. We’re talking primarily entertainment, certainly not the most important thing in the world. Yes, it’s true that 3-D vision is associated with movies and now television. 3-D vision is not vital to life as we know it. However, that’s the short sight. Life as we know it is changing. One of those changes is the immersion of human beings in the online world. Viewing the online in three dimensions – the more lifelike the better – will add to that experience and hasten the day when people will find ‘living online’ to be as acceptable as most other kinds of living. It’s part of what is called ‘virtual reality’ or VR. I’m not saying this is a good thing, only that adding realistic 3-D will be a big factor. So yes, the search for viewing images in three dimensions – without using special glasses – may have a lot of impact.
This brings me to a recent announcement by Microsoft. It’s a new type of lens designed and developed by the Microsoft Applied Sciences Group to make 3-D presentation on-screen – no glasses.
Microsoft is hardly alone in this, especially with competition from manufacturers using 3-D lenticular lenses for no-glasses displays, but the Microsoft approach is both novel and difficult. What I’m saying is that if this weren’t Microsoft making the announcement, the future of such an approach might be bleak. Central to the approach is controlling where the light from the display goes. In the current demonstration model, the Microsoft screen can project 3-D video to two people at the same time at any viewing position. Most of the other approaches can also direct light toward two viewers but only if they sit in designated positions.
A technical trick, and a costly part of the approach, is that the Microsoft screen uses a camera to track the position of viewers. This too is not a new idea, but until recently it was too expensive to have the computing power required to make it work. It was also difficult to make a screen vary its output into specific directions (angles of viewing).
To do it, Microsoft uses a lens that is about 11 mm thick at the top and 6 mm thick at the bottom. This design allows the light coming from the projection to ‘bounce around’ inside the lens until it becomes focused for viewing, or as they say, it reaches a critical angle designated by the camera as correct for a person sitting at a particular position. This process is, in general, under control of light emitting diodes at the bottom of the screen, which direct the flow of light within the lens.
Microsoft believes the 3-D lens can be used as a backlight for traditional LCD (Liquid Crystal Display). However, the quality of the picture depends on the LCD refresh rate – the faster the better – as does the number of people who can watch simultaneously in 3-D. In the requirements for the LCD Microsoft must join the line of those asking the LCD manufacturers to change their specifications. This is where being Microsoft might make a difference.