Qualcomm cuts deals for its Mirasol displays

Qualcomm made about eight different announcements at the Mobile World Congress today, but most interesting was news of the company’s progress Mirasol displays, which are based on a new way of capturing light with micro-electro-mechanical semiconductor (MEMS) technology.

Qualcomm said it’s working with LG Electronics to develop Mirasol-enabled cell phones that use much less power than today’s liquid crystal display-based cell phones.  Qualcomm also has separate deals with Inventec and Cal-Comp, a subsidiary of Taiwanese phone maker Kinpo Electronics.

Qualcomm has been talking about the technology since 2007, when its Qualcomm MEMS Technologies division announced the first direct-view MEMS display for mobile devices. The technology uses MEMS chips to capture ambient light, resulting in displays that require no backlighting and so consume a lot less power than standard displays in portable devices.

The displays work by reflecting light so that specific wavelengths interfere with each other to create color. Phones using the displays can consume a lot less power.

As Qualcomm describes it, each element in a MEMS display is a device composed of two conductive plates. One is a thin film stack on a glass substrate, the other is a reflective membrane suspended over the substrate. The gap between the two is filled with air. The element has two stable states. When no voltage is applied, the plates are separated and light hitting the substrate is reflected. When a small voltage is applied, the plates are pulled together by electrostatic attraction and the light is absorbed, turning the element black.

The elements have memory which works somewhat like the pull top on an aluminum can. Once the reflective membrane has been pulled down, it requires less energy to hold it than was exerted in pulling it down. So power usage is near zero in situations where the display image is unchanged. This is where LCD displays fall short.

The MEMS displays are extremely fast, switching from one color to the next in tens of micro-seconds, and they’re born from the same sort of MEMS technologies that Texas Instruments uses to create high-powered video projectors inside cell phones. MEMS chips are changing the electronics world. They’re used in everything from Nintendo’s Wii game console controller to rear-projection TVs.