Compact scan module with magnetically centered scan mirror
AssigneeSymbol Technologies, Inc.
InventorsEdward Barkan, Howard M. Shepard, Mark E. Drzymala
Life of this patent
Estimating the term…
Abstract
A non-retroreflective compact scan module in an electro-optical reader includes a laser light source, a photosensor and an electromagnetic coil mounted at one surface of a printed circuit board. The laser emits a laser beam perpendicular to the board, and is redirected to an oscillatable scan mirror which is magnetically centered to a rest position when the coil is de-energized. Electrical circuitry is mounted at an opposite surface of the board.
Claims14
A scan module for use in a reader for electro-optically reading indicia, comprising:
- a) a support;
- b) a light source mounted on the support, and operative for producing a light beam;
- c) a scan mirror mounted on the support for oscillating movement between opposite end-limiting positions;
- d) optical means mounted on the support, and operative for directing the light beam from the source to the scan mirror for reflection therefrom toward the indicia;
- e) a permanent magnet mounted on the scan mirror for joint oscillating movement therewith, the permanent magnet having opposite magnetic poles spaced apart along a magnetic axis;
- f) a drive, including an energizable electromagnetic coil mounted on the support, and operative for magnetically interacting with the permanent magnet when energized, and for oscillating the scan mirror between the end-limiting positions to sweep the light beam in a scan across the indicia for reflection therefrom;
- g) a collection lens mounted on the support, and operative for collecting light reflected from the indicia;
- h) a sensor mounted on the support, and operative for detecting light collected by the collection lens, and for generating an electrical signal related to the indicia being read;
- and
- i) a pole piece having a pair of ferromagnetic material pole portions mounted on the support and spaced apart along the magnetic axis, the poles of the permanent magnet being magnetically attracted to the pole portions for centering the scan mirror in a rest position between the end-limiting positions when the coil is not energized.
An arrangement for centering an oscillatable scan mirror in a rest position in a reader for electro-optically reading indicia, comprising:
- a) a support;
- b) a permanent magnet having opposite magnetic poles spaced apart along a magnetic axis;
- c) a hub on which the scan mirror and the magnet are mounted for joint oscillating movement relative to the support between opposite end-limiting positions;
- d) an energizable electromagnetic coil mounted on the support, and operative for magnetically interacting with the magnet when energized, and for oscillating the scan mirror between the end-limiting positions to sweep a light beam incident on the scan mirror in a scan across the indicia during reading;
- and
- e) a pole piece having a pair of ferromagnetic material pole portions mounted on the support and spaced apart along the magnetic axis, the poles of the permanent magnet being magnetically attracted to the pole portions for centering the scan mirror in a rest position between the end-limiting positions when the coil is not energized.
Dependencies are inferred from the claim text.