Optical navigation device with image sensor and inner housing

Abstract

An optical navigation device that can sense the movement of an object, such as a user's finger, so that the movement can control a feature of a consumer digital device such as a cursor on a display screen. The device includes a substrate to which an LED, reflector, and image sensor are attached. Light from the LED is directed by the elliptical reflector toward and through a window that is transparent to the light from the LED and then is reflected off of the user's finger back through the window, through a lens, and onto the image sensor. The reflector is positioned to direct light toward the window at an oblique angle, in the range of 65 to 70 degrees from an angle normal to the window. Further, the reflector is curved to gather light across a large solid angle in the vicinity of the LED. The curved shape of the reflector may be a portion of an ellipsoid and the LED may be located at one of the foci of the ellipsoid, with the window located at the other foci of the ellipsoid.