Computer mouse benefits from dark field microscopy technology

Today’s optical and laser computer mice offer accurate tracking but have trouble handling shiny surfaces or glass. With more people using laptops, they are more likely to use their computer on shiny surface such as a dining room table, a kitchen counter, or a table at the local coffee shop. Logitech set out to develop a mouse that could handle any surface without requiring a mouse pad. The company considered Doppler radar, UV imaging and interferometry techniques but decided that the principles of darkfield microscopy were the best solution.

Standard optical and laser mice use a light source to illuminate the surface, and a lens captures the scattered light. An image sensor with an onboard processor processes the generated image, using minute differences between images to determine the direction and speed of motion. Since glass and shiny surfaces may have very few irregularities, it can be hard for the sensor to identify reference points for measuring motion.

Dark field illumination can help reveal microscopic details of a shiny tracking surface because it contrasts small particles such as dust or scratches against a black background. The Logitech implementation of the technology uses two lasers to more effectively collect details from a shiny surface and switches to only one laser when used on a normal surface. The Logitech Darkfield Laser Tracking technology is used in the company’s Anywhere Mouse MX and Performance Mouse MX, which were introduced last month.

Read more about this technology here and the mice here.