The vast majority of attention focused on wearables has been on devices with an integrated screen, such as the Apple Watch. The general consensus seems to be that screens are necessary to provide the kinds of notifications and other forms of information for which many believe wearables are well suited.

But a new breed of screenless wearables are starting to make their mark and I believe they will become an increasingly important part of the wearables industry, especially for wristworn-wearables like smart watches. The latest entries come via luxury watch maker Movado, with help from HP, but there are other interesting examples, including the Chronos add-on disc for traditional watches, that are coming soon.

For certain types of information, such as text messages or maps, screens are really the only option. However, at these very early stages of wearables' evolution, it's worth asking important questions about whether or not that type of information is the most appropriate or best data for wearables to offer.

Screenless wearables are clearly more limited in the type and range of information they can offer, but also have the possibility of being more effective with a simpler set of information. Leveraging haptics technologies that provide physical feedback to your body---and then adding in audio-based information---screenless wearables are likely to drive forward completely new user interface paradigms and methods of interaction. Used in conjunction with smartphones, they can also provide a great deal of detailed visual information to the user/wearer of the device---but in a different way.

As mentioned above, screens are great for delivering certain types of information, but they bring with them a number of issues. First of all, they immediately date a device and, arguably, limit their useful lifetime. Screen technology continues to evolve and improve at such a rapid pace that it's easy to spot older technology by simply looking at the type and quality of the screen it has. Five years from now, today's wearables screens will look horribly outdated. Compared to many watches---whose designs can still look fresh even several decades later---that's a step in the wrong direction.

I think the limitations of a screenless device could actually end up driving very creative new solutions for device interactions.

Another problem with screen-based wearables is that they can be a bit too good at notifying both you and others around you that a new piece of data or notification has come in. When your screen lights up your wrist, it's announcing to the world (and especially those right around you), that something is going on with you. In some cases, it might even be possible for people to read those screens---even in situations that you would prefer that they can't.

For those of us with older eyes, many of whom grew up as part of a generation who are more accustomed to regularly wear watches, the opposite problem can also occur. Reading a screen designed to fit on your wrist can be a real challenge for many people.

Yet another limitation with screens on wearables is the impact they have on the battery life of the device. Screen-based devices typically measure their battery life in hours or maybe a day, but screenless devices battery lives are measured in weeks.

The trick to making screenless devices effective is going to be smart usage of physical feedback mechanisms and the development of new user interface paradigms. Figuring out how to do things like leverage waveform synthesis to create a range of haptic feedback-based sensations could be incredibly important in creating new types of interaction models. Combine that with some visual cues and a high-quality audio experience---speak to the device and receive useful audio information and/or notifications, for example---and you could set the groundwork for an entirely different way of thinking about and using devices.

Doing this kind of work won't be easy, but I think the limitations of a screenless device could actually end up driving very creative new solutions for device interactions. In addition, work done in this area should lead to the disappearance of the more obvious aspects of technology and a more seamless integration of the key capabilities it enables into our everyday lives.

Bob O'Donnell is the founder and chief analyst of TECHnalysis Research, LLC a technology consulting and market research firm. You can follow him on Twitter . This article was originally published on Tech.pinions.

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