ST intros optical joystick chip for handheld consumer devices

GENEVA, SWITZERLAND: STMicroelectronics has introduced an ultra-low-power IC containing all the functions necessary to control an Optical Finger Navigation (OFN) module or optical joystick.

The VD5376 optical joystick controller helps users interact with the increasingly sophisticated features of portable electronic products, such as smartphones, laptop PCs, netbooks, media players, GPS devices and remote controls for home-entertainment equipment.

The new VD5376 controller chip has been designed into new smartphones by leading mobile phone manufacturers and is being evaluated by major PC companies for use in portable computing devices and by TV and set-top-box makers for remote controllers.

An optical joystick, or OFN module, enables mobile users to enjoy increased accuracy and flexibility of a desktop-PC mouse while allowing consumer manufacturers to save space with the integration of this smallest of user interfaces, in contrast to other technologies, such as touchscreens, that are often not accurate enough for emerging mobile applications. Actions such as pinpointing map locations, selecting hyperlinks on web pages, or adjusting playback volume using a touch-sensitive slider can be difficult or imprecise when using touch control directly on-screen.

Another alternative, touchpads, are significantly larger than OFN modules and do not operate as efficiently when moisture is present or the user is wearing gloves. Still other devices, such as trackballs or buttons, are even less suited for small handheld products.

Using an OFN module to control an on-screen cursor helps next-generation products overcome these limitations. The module is embedded in the outer casing, and incorporates a light source similar to that of a desktop optical mouse. When the user moves a fingertip over the surface of the module, the VD5376 controller IC measures the tiny movements to produce a corresponding change in cursor position on the screen.

ST's VD5376 contains all the features necessary to manage an OFN module, and is supplied as a bare die that can be easily incorporated into next-generation modules delivering the high performance and power efficiency demanded by today's handheld markets. Features include a highly sensitive and reliable imaging array for detecting finger movement, as well as driver circuitry for the light source.

This chip is compatible with laser, infrared or optical LEDs, thereby maximizing flexibility for module builders. In addition, advanced power-management capabilities contribute to the device's low overall power consumption, ultimately resulting in longer battery life for end products.

"This new combo sensor-controller chip leverages both ST's know-how in optical mouse ICs and the company's leading expertise in CMOS imaging for mobile products," said Arnaud Laflaquiere, Sensors Business Unit Director, Imaging Division,
STMicroelectronics. "With this device, we are aiming to significantly penetrate the wide and fast growing range of mobile applications that are adopting optical finger navigation to simplify the human interface."

The VD5376 is available immediately in sample quantities and mass production, as bare die priced at $0.40 above 100,000 units.