A method and system for an optical navigation device configured to
generate navigation information through a transparent layer.
Specifically, the optical navigation device includes a light source that
is configured to illuminate a reflective surface through a layer that is
optically transparent to the light source. A sensor is configured to
generate navigation information in response to light reflecting off the
reflective surface. The sensor is configured with a depth of field to
support a distance between the sensor and the reflective surface. A
contact sensor is also included to indicate when the optical navigation
device is no longer in contact with the transparent layer. The contact
sensor allows for skating functionality for the optical navigation
device.