Those who are curious about the future of display technology in communications may wish that they had access to that most ancient wireless display device: the crystal ball. This approach, however, has a number of drawbacks. While simple in construction, the spherical glass communicator with the hands-on user interface is tough to operate, typically requiring a trained specialist. Its use is further limited by a non-standard, poorly documented video interface that's only compatible with a poorly understood and unreliable communications "medium."
Even when reception is steady, image quality can be limited by low resolution and distortion caused by curvature of the glass. Image size, brightness, and viewing angle also may be restricted, because users are forced to hover over the display. Advocates might point out that the device's very low power consumption makes it a candidate for some portable applications. Unfortunately, its fragility, weight, size, and odd form factor automatically disqualify it for service in most of today's handheld communications products.
Luckily, there are alternatives to the crystal ball. Current market trends give us some indications of the display performance levels that will be required a few years from now. As a starting point, consider cellular phones. According to David Mentley of Stanford Resources, San Jose, Calif., the cell-phone industry can be expected to generate $2 billion in revenue by 2003. Given the size of this market, its products will clearly drive much of the development of portable-display technology.
Existing requirements for these products' displays will either remain or grow more stringent. Designers will aim for smaller size, lighter weight, lower power, less cost, better readability in variable ambient lighting, and greater durability. Take power, for example. An existing paradigm for mobile phones is that they must provide eight hours of operating time and 24 hours of standby time on a single battery charge. But manufacturers are pushing to raise these numbers through the development of better batteries and more power-efficient designs.
On the battery side, improvements in lithium-based cell chemistries, such as Li-ion, Li-polymer, and Li-S, will produce higher energy densities.While some of this additional energy will probably go to increasing operating time, it also will give designers the option of switching from monochrome to the more power-hungry color displays. Of course, display vendors will be working to reduce this power penalty by developing more efficient LCD and alternative technologies.
The demand level for displays that can deliver high information content is going to depend largely on the pace of development in wireless networks. Today, those networks typically provide data communications at 14.4 kbits/s, which limits them to tasks like downloading e-mail and text-only web sites. Such applications can be handled by the low-resolution LCDs currently found in portable cell phones and wireless-enabled PDAs. But as wireless service providers upgrade their networks to third-generation standards, data rates will rise into the range of hundreds of kbits/s and beyond, allowing transmission of color graphics and video.
For wireless phones and other handheld information products, the need for color graphics and video will grow as more of them connect to the Internet. The Gartner Group, Stamford, Conn., states that by 2004, 70% of new cell phones and 40% of new PDAs will use wireless technology for direct access to web content and enterprise networks. Increases in the bandwidth available for such data connections will move us beyond text-based web access, to the live-action color graphics we've grown accustomed to on our desktop and notebook PCs.
Indeed, expectations for portable devices have been raised substantially by the quality of images produced by the active-matrix LCDs (AMLCDs) found in our notebooks. Factor in the emergence of communications products with built-in digital cameras for transmitting still or moving images, and those low-resolution monochrome displays run out of steam.
A transition to 800- by 600-pixel SVGA looms ahead, as this is the standard specified by Windows that also accommodates both NTSC and PAL video. To save power, though, some applications will likely opt for lower resolution, such as quarter VGA.
Jumping up to SVGA will require a move away from the direct-view LCDs that are now prevalent. In current cell-phone designs, displays are generally monochrome passive-matrix LCDs with 1- to 2-in. maximum diagonal measurements and resolutions in the neighborhood of 60 by 90 or 120 by 90 pixels. For handheld organizers or PDAs, which are making inroads as communications devices for e-mail, the displays tend to run a bit larger. They go up to about 3.9 in. with quarter-VGA (320 by 240) resolution. In certain cases, vendors have begun opting for the more expensive, thin-film-transistor-based AMLCDs to obtain color. But in doing so, they will sacrifice some battery life.
Even though these direct-view LCDs are ill-equipped to handle heavy graphics and video, they probably won't disappear anytime soon. Improvements in their design will produce thinner and lighter displays, with lower power and greater brightness and contrast. Sharp Microelectronics has gone into production with a liquid-crystal-on-plastic display. It is said to produce thinner, lighter, and more reliable displays than those fabricated with the usual liquid-crystal-on-glass. In the future, such an approach may foster the creation of cell phones that are thin enough to withstand flexing.
Those who are curious about the future of display technology in communications may wish that they had access to that most ancient wireless display device: the crystal ball. This approach, however, has a number of drawbacks. While simple in construction, the spherical glass communicator with the hands-on user interface is tough to operate, typically requiring a trained specialist. Its use is further limited by a non-standard, poorly documented video interface that's only compatible with a poorly understood and unreliable communications "medium."
Even when reception is steady, image quality can be limited by low resolution and distortion caused by curvature of the glass. Image size, brightness, and viewing angle also may be restricted, because users are forced to hover over the display. Advocates might point out that the device's very low power consumption makes it a candidate for some portable applications. Unfortunately, its fragility, weight, size, and odd form factor automatically disqualify it for service in most of today's handheld communications products.
Luckily, there are alternatives to the crystal ball. Current market trends give us some indications of the display performance levels that will be required a few years from now. As a starting point, consider cellular phones. According to David Mentley of Stanford Resources, San Jose, Calif., the cell-phone industry can be expected to generate $2 billion in revenue by 2003. Given the size of this market, its products will clearly drive much of the development of portable-display technology.
Existing requirements for these products' displays will either remain or grow more stringent. Designers will aim for smaller size, lighter weight, lower power, less cost, better readability in variable ambient lighting, and greater durability. Take power, for example. An existing paradigm for mobile phones is that they must provide eight hours of operating time and 24 hours of standby time on a single battery charge. But manufacturers are pushing to raise these numbers through the development of better batteries and more power-efficient designs.
On the battery side, improvements in lithium-based cell chemistries, such as Li-ion, Li-polymer, and Li-S, will produce higher energy densities.While some of this additional energy will probably go to increasing operating time, it also will give designers the option of switching from monochrome to the more power-hungry color displays. Of course, display vendors will be working to reduce this power penalty by developing more efficient LCD and alternative technologies.
The demand level for displays that can deliver high information content is going to depend largely on the pace of development in wireless networks. Today, those networks typically provide data communications at 14.4 kbits/s, which limits them to tasks like downloading e-mail and text-only web sites. Such applications can be handled by the low-resolution LCDs currently found in portable cell phones and wireless-enabled PDAs. But as wireless service providers upgrade their networks to third-generation standards, data rates will rise into the range of hundreds of kbits/s and beyond, allowing transmission of color graphics and video.
For wireless phones and other handheld information products, the need for color graphics and video will grow as more of them connect to the Internet. The Gartner Group, Stamford, Conn., states that by 2004, 70% of new cell phones and 40% of new PDAs will use wireless technology for direct access to web content and enterprise networks. Increases in the bandwidth available for such data connections will move us beyond text-based web access, to the live-action color graphics we've grown accustomed to on our desktop and notebook PCs.
Indeed, expectations for portable devices have been raised substantially by the quality of images produced by the active-matrix LCDs (AMLCDs) found in our notebooks. Factor in the emergence of communications products with built-in digital cameras for transmitting still or moving images, and those low-resolution monochrome displays run out of steam.
A transition to 800- by 600-pixel SVGA looms ahead, as this is the standard specified by Windows that also accommodates both NTSC and PAL video. To save power, though, some applications will likely opt for lower resolution, such as quarter VGA.
Jumping up to SVGA will require a move away from the direct-view LCDs that are now prevalent. In current cell-phone designs, displays are generally monochrome passive-matrix LCDs with 1- to 2-in. maximum diagonal measurements and resolutions in the neighborhood of 60 by 90 or 120 by 90 pixels. For handheld organizers or PDAs, which are making inroads as communications devices for e-mail, the displays tend to run a bit larger. They go up to about 3.9 in. with quarter-VGA (320 by 240) resolution. In certain cases, vendors have begun opting for the more expensive, thin-film-transistor-based AMLCDs to obtain color. But in doing so, they will sacrifice some battery life.
Even though these direct-view LCDs are ill-equipped to handle heavy graphics and video, they probably won't disappear anytime soon. Improvements in their design will produce thinner and lighter displays, with lower power and greater brightness and contrast. Sharp Microelectronics has gone into production with a liquid-crystal-on-plastic display. It is said to produce thinner, lighter, and more reliable displays than those fabricated with the usual liquid-crystal-on-glass. In the future, such an approach may foster the creation of cell phones that are thin enough to withstand flexing.