1. An optical navigation device comprising: an image sensor to generate images of a tracking surface, wherein the image sensor has a field of view via imaging optics interposed between the image sensor and the tracking surface; a light source to generate light to illuminate a portion of the tracking surface; and illumination optics interposed between the light source and the tracking surface to direct the light from the light source toward the tracking surface, wherein the illumination optics comprise an output surface with a primary region of the output surface illuminated above a threshold intensity, wherein a primary direction of propagation of the light from the output surface of the illumination optics is the same as a primary direction of propagation of the light into the illumination optics; wherein the illumination optics are located relative to the tracking surface so that, during a navigation mode, a mirror image of the output surface, relative to the tracking surface, is located to exclude the primary region from the field of view of the image sensor.