STMicroelectronics Introduces Optical Joystick Chip Enabling Low-Power Cost-Effective Navigation in Handheld Consumer Devices

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.”