Optimizing Signal Collection in a Holographic Scanner
Original Publication Date: 1988-Jan-01
Included in the Prior Art Database: 2005-Feb-14
In a holographic scanner 10 shown in Figs. 1 and 2, light backscattered along a conical path 12 from an object scanned by beam 14 falls on a hologram facet 26 and then on a lens 16. The lens 16 focuses this light onto the scanner's system detector 18. The collection area of the hologram facet 26 changes as the disk moves. To maximize collected signal strength for a given facet while keeping the collected signal uniform across all points on the scan line, the edge of the hologram's collection area should substantially coincide with the projected edge of the collector lens when the hologram is at its full rotation as shown in Fig. 3. For an aspheric collection lens, the lens surface facing the disk is steeply curved.