A whole new perspective

Computer screens today are fast, bright and colourful - but their images are, well, rather flat. Sandra Vogel views the first steps into the third dimension

Today's computer screens are light years ahead of the displays of the first generation. When those early screens flickered into life more than 30 years ago, text of one colour (white, orange and green were popular) sat on a background of another colour (black). Anyone who remembers Sinclair's ground-breaking colour computer, the Spectrum, will remember the joy of seeing eight colours at once, the thrill of watching drawing-pin sized blocks of vivid graphic elements join together to form gaming environments, and the frustration of "attribute clash" - the splodging caused when these colour blocks visually collided on screen.

Today's computer screens are light years ahead of the displays of the first generation. When those early screens flickered into life more than 30 years ago, text of one colour (white, orange and green were popular) sat on a background of another colour (black). Anyone who remembers Sinclair's ground-breaking colour computer, the Spectrum, will remember the joy of seeing eight colours at once, the thrill of watching drawing-pin sized blocks of vivid graphic elements join together to form gaming environments, and the frustration of "attribute clash" - the splodging caused when these colour blocks visually collided on screen.

Since then colour screens have developed in several directions: an exponential rise in the number of colours that can be shown at one time (now in the millions); a fall in the size of individual blocks of colour (pixels); the development of ever-larger affordable monitors; and, most recently, flat-screen TFT (thin-film transistor) displays for desktop use.

These moves have relied for their success on advances in screen technology, processor power and software support. Graphics-card manufacturers and software developers have been crucial contributors. And they've worked together well, getting home and professional users to the point where they can watch DVD movies, conduct video conferences and run complex, graphics-rich simulations such as walk-throughs of architects' plans, virtual tours of historic locations, and cross-sections of human organs.

But one thing has not changed: it all happens in two dimensions. The next leap forward is the long-awaited move into into another dimension. Three-dimensional screens have been on the wish list for the corporate and entertainment industries for many years. In 1954, a 3D version of Alfred Hitchcock's Dial M for Murder rode on a short-lived wave of interest in the 3D film format. Since then, sporadic releases of 3D versions of standard cinema movies have given way to specialist movie theatres capable of mixing 3D with other "immersive" technologies, such as the vast screens seen in the IMAX chain.

The biggest drawback of that format is the need to wear special glasses to fool your eyes into seeing in three dimensions something that is presented in two. The goal is to deliver 3D without viewing aids. This has proved unachievable in the cinema, and only recently have the first computers achieved it on a commercial basis.

Sharp has proved itself to be the most successful of those working towards 3D screens, having last year brought a 3D laptop to market in the United States. The Actius RD3D is a standard laptop, running on Windows XP Professional, with a 60GB hard disk, Intel Pentium 4 pro- cessor and a 15-inch display. It is not available outside the US, where it costs more than $3,000 (£1,600).

The technology behind the display enables the viewer to take advantage of 3D still and moving images without sacrificing 2D viewing. It's relatively simple. Standard laptops have a single LCD screen, and this is replicated in the RD3D, allowing you to work as usual. Tap a button, and a second LCD sparks into life. This lacks the electricity-driven pixels that form the images on normal displays. Instead, it simply throws light on to what Sharp calls a "latent parallax barrier". (Parallax is the way distant objects seem to move relative to closer ones when viewed from different places.)

This barrier is the key. It divides the screen into vertical strips of pixels and directs them alternately to the left and right eye of the viewer. As when you look through a stereoscope (which creates 3D views from two photos taken from slightly different points), your brain fuses the two different images into a single 3D image.

The RD3D is remarkably effective. I tried the machine on a visit to Sharp's labs in Oxford, where the technology was developed. It acquitted itself well through several tasks, including looking at 3D photos and playing a 3D game. I quickly got used to sitting in just the right position to make the most of the perspective, and not straying outside of the optimum viewing window.

In real-life work situations, where people naturally shift about in their chairs, imperceptibly altering their viewing angle, it might prove more difficult to maintain optimum viewing. And, because the acceptable viewing window is relatively small, this is a one-user-at-a-time experience. Still, it works, and it works well.

The RD3D is not Sharp's first 3D display. The company has had some success with mobile phones launched in Japan: 1.5 million of its SH251i model were sold between its launch at the end of 2002 and its replacement by the SH505i in June last year. These were capable of showing 3D images of a remarkably high quality. And Sharp isn't alone in the field: NEC has announced a laptop with a 3D screen, the LaVie S LS900/8E, using Sharp's technology.

However, the screen is only one part of a computer, and Sharp can't deliver anything without support, most notably from software developers and graphics-chip makers. The RD3D uses software from third parties such as DDD (www.ddd.com), and the graphics software company nVidia provides programming tools.

There's also a 3D consortium, led by five founder bodies, including Sharp, Sanyo, Sony, NEC and Hitachi, with others whose visual-display portfolios span computing and entertainment. If these firms succeed in developing standards, 3D displays could get much wider application.

That's a big "if", though. Getting products to market and having them succeed are different tasks, and how far we can go down the 3D road remains to be seen. There are applications in, say, medicine, engineering, architecture, education and PC gaming. But usability can only be tested to a certain point in the lab. If real users don't like the technology, it won't succeed.

There is a precedent. In the Nineties, virtual-reality games could be found in entertainment arcades. They looked set for a huge market, especially for home versions. But problems arose: users could feel sick, and were advised against driving too soon after use. Screens offering 3D don't have those problems, but there's always the risk that an innovative technology will encounter something that trips it up.

network@independent.co.uk