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Portable laser scanning system having a motor drive with no DC windings

  • US 5,126,545 A
  • Filed: 01/16/1990
  • Issued: 06/30/1992
  • Est. Priority Date: 01/16/1990
  • Status: Expired due to Term
First Claim
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1. A scanning device for repetitively scanning a target, said device having a laser beam generating means, at least one high speed scanning motor having a reflection means mounted on a drive shaft of said high speed scanning motor for directing the laser beam provided by said laser beam generating means, and a motor drive circuit being an open-loop control system for adjusting the amplitude of oscillation of the scanning motor to a predetermined level and presetting the frequency of oscillation of the scanning motor to a predetermined level comprising a waveform generation means to supply a first and second periodic, time varying triangular waveform to a pair of stator windings in the scanning motor, said first and second periodic, time-varying triangular waveforms being of equal magnitude and 180 degrees out of phase with respect to one another so as to cause increasing and decreasing current flow in alternate stator windings of said pair of stator windings and corresponding increasing and decreasing magnetization in said alternate stator windings, said increasing and decreasing magnetization in alternate stator windings providing smooth reflection means rotation and to maximize said reflection means rotation.

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