The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 30, 2000
Filed:
Oct. 20, 1998
John G Hughes, Winter Park, FL (US);
Lockheed Martin Corporation, Bethesda, MD (US);
Abstract
An optical scanner includes a support frame which rotatably supports a mirror. A stepper motor is provided for turning a cam which abuts the mirror. The motor imparts force to the mirror to define a scan profile when the cam is rotated. The scanner further includes a resilient member which applies force to the mirror, which, in turn, counteracts and cancels the force provided by the cam. Due to the cancellation of the force provided by the cam and the resilient member, no bending forces are applied to the mirror. The optical scanner further includes a control mechanism for applying sinusoidal currents to the stepper motor. More specifically, the control mechanism provides sine and cosine waveforms, and the control mechanism commutates the motor with the sine and cosine waveforms. The sine and cosine waveforms are pre-stored in a memory. In exemplary embodiments, the control mechanism provides constant velocity in one direction, and a fast retrace in an opposite direction. The control mechanism controls the motor without the use of feedback, thereby reducing the complexity and cost of the scanner.