Abstract: An emitter lens is provided between the radiation source and the work surface to be illuminated. The emitter lens collects radiation and reshapes the illumination pattern to increase intensity and uniformity. The radiation source and emitter lens have associated housings which act to properly orient and align the emitter lens and radiation source. The emitter lens also acts to space the radiation source from an aperture in a housing of the computer input device to provide protection against damage due to electrostatic discharge (ESD). An imaging lens is provided between the work surface and the image sensor to focus light reflected from the work surface onto the image sensor. An imaging lens housing or holder is provided to properly orient and align the imaging lens with the image sensor. The imaging lens housing provides an apron which increases ESD discharge path length.