This part is a kind of semiconductor called ADNS-5020.

Function of this product has Optical Mouse Sensor.

Manufacturers : Agilent Technologies

Image and pinout :

Some of the text within the PDF file :

Agilent ADNS-5020 Small Form Factor Optical Mouse Sensor Preliminary Product Overview Description Small Form Factor Optical Mouse Sensor for Optimum Precision Navigation Performance in Mice Applications The Agilent Technologies’ ADNS-5020 is an entry-level, small form factor optical mouse sensor. With many built-in features including an internal 24MHz oscillator and LED driver, this minimizes requirements for external components. Also, this sensor is optimized for LED-based corded applications in home and office environments, enabling navigation on virtually all surfaces. magnitude of movement is then mathematically determined. The ADNS-5020 is capable of high-speed motion detection – up to 14ips velocity, and 2g acceleration. Frame rate is adjusted internally to optimize surface trac [ ... ]

ADNS-5020 PDF Datasheet Download