Some wearable HealthTech devices simply record data and wirelessly transmit it to some other device for processing, analysis, and reporting. The person wearing the device has little need to interact directly with it, relying instead on the user interface of some other device such as smartphone to convey the information. As a result, many wearable HealthTech devices do not display much, often limited to a single LED to indicate power, or perhaps a small segmented display to show time or other simple information.
This view is changing, however. The Apple Watch has focused attention on the prospect of using the wearable device itself as the source of information for the user. By its very nature, we want wearable devices to be small and unobtrusive. This means that we need to be clever with the available display area so that it can present as much information — and as many different kinds of information — as possible. It also should be easy to read in the dark, have excellent power efficiency, and a fast response time. And good color would be nice.
Apple has chosen OLED (organic LED) technology for the Watch display. It probably costs a bit more than an equivalent LCD, but it’s also probably thinner and lighter than an LCD panel. Digitimes Research believes that OLED will be the winning choice for wearables in the coming years. They expect the technology to be used in more than 70% of the smartwatches that will ship in 2015. They expect the wearable display market to have a compound annual growth rate (CAGR) of 25% through 2020. The company predicts that 20 million smartwatches will ship in 2015 alone.