Optical scanners in current use can be divided neatly into two basic families: devices with no moving mirror such as cathode ray tubes and electro- and acousto-optics, and electro-mechanical devices. This paper is limited to the latter group. Discussed are the five generic types, the attributes and limitations of each, ancillary equipment such as drives and control circuits and, in a general way, the suitability of each for various applications. X-Y scanning is covered. Because of the current interest in bar code scanning both laser and white light bar code systems are presented in some detail to illustrate the optical and electronic elements of systems incorporating electro-mechanical scan-ners. Throughout this paper, references to scan angle mean the angular motion of the mirror, not that of the reflected beam. Beam motion is double the mirror scan angle.
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