The detector elements are larger than an image of the spot on the array would be, but an image is not formed on the array. Instead, the beam shaping element enlarges the size of the area of illumination on the array slightly, and mixes, or homogenizes, the light. This destroys the image and the intensity...http://www.google.ca/patents/US6624899?utm_source=gb-gplus-sharePatent US6624899 - Triangulation displacement sensor
