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Automatic Shifting Laser Scan Pattern

IP.com Disclosure Number: IPCOM000088506D
Original Publication Date: 1977-Jun-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Swanson, LH: AUTHOR [+2]

Abstract

Laser scanners have optical properties which make them very useful as scanners. However, in many environments stringent safety regulations must be met. One such regulation is directed to the cumulative radiation at a given location. Thus, a scanning pattern which is substantially reproduceable will accumulate more radiation at a given point than the same pattern which is shifted periodically.

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Automatic Shifting Laser Scan Pattern

Laser scanners have optical properties which make them very useful as scanners. However, in many environments stringent safety regulations must be met. One such regulation is directed to the cumulative radiation at a given location. Thus, a scanning pattern which is substantially reproduceable will accumulate more radiation at a given point than the same pattern which is shifted periodically.

This article describes an electronic technique for causing a shift of a scanning pattern which results in a reduced accumulation at any given point in the scanning window of a laser scanner. The figures illustrate two scan patterns shifted +/-10 Degrees from a 0 Degree phase shift reference. When these patterns are alternated in a scan window, the radiation accumulated at any given point is reduced substantially over that accumulated if a constant 0 Degree phase shift pattern is used.

Many techniques are available for implementing the above. In a system utilizing a shutter for closing the scanning window between scan patterns, the shutter control signal may be used to switch an electrical delay into and out of the beam deflection control circuits, thus causing alternate scan patterns to be +/-10 Degrees from 0 Degrees phase. Alternatively, the clock which controls the deflection circuits may be caused to change periodically, thus changing the phase of the pattern. In those scanning systems having a shutter, the shutter- controlled shift...