A symbol reader is disclosed that uses a dynamic random access memory 24 as a detector element and a gradient refractive index material as the lens 14 to capture a symbol image. The rod shaped lens 14 passes through an opaque cover 26 and confronts the array of memory elements in the memory 24. The cover...http://www.google.com.au/patents/US5136145?utm_source=gb-gplus-sharePatent US5136145 - Symbol reader
