Optical symbol (bar code) reading systems having an electro-optic

Abstract

A miniature scan engine module for bar code reading and data collection systems utilizes a light source and a light collector flexurally supported on a platform which reciprocates on pivots defined by flexures. The light received from the code, as it is scanned, is collected along an optical collector having a surface area approximately equal to the surface area of one side of the scan engine. The optical collector in which the gratings are embedded faces the bar code and pivots with the scanning beam source (a laser diode). A pair of diffraction gratings in a surface of the optical collector which faces away from the code directs the incoming light so that it propagates internally in a substrate within the body of the collector, i.e. in the optic itself to photodetectors via reflective and light concentrating surfaces over the photodetector. Efficient light collection capability, without the need for special optics such as lenses and collection mirrors, enables the scan engine to be configured so that it occupies a miniature volume. A data collection system, in the form of a portable terminal, has a housing which provides the handle for a scanning accessory which is the scan engine module.