Flying spot optical scanner with a high speed dithering motion
First Claim
1. In a scanner for electro-optically reading indicia by sweeping a scan spot of light along a longitudinal axis in a sweeping movement across the indicia, and by detecting light reflected off the indicia to generate an electrical signal indicative of the detected light,an arrangement for compensating for defects in the indicia that cause reading errors, the arrangement comprising:
- means for dithering the scan spot during said sweeping movement by oscillating the scan spot back and forth in opposite directions across said longitudinal axis in a transverse direction generally orthogonal to said longitudinal axis to generate a dithered scan spot that creates high frequency signal components corresponding to said defects in said electrical signal.
2 Assignments
0 Petitions
Accused Products
Abstract
An optical scanner includes a light source for producing a light beam for scanning a target wherein the light beam scans a target at a first low frequency and the beam also dithers in a direction orthogonal to the scanning direction at a second, high frequency. The dithering motion can be imparted by a oscillating mirror and allows improved reading of, for example, bar code symbols. In addition an optical scanner includes a laser light source producing a laser light beam into which a time-varying phase is introduced in order to reduce laser speckle noise.
51 Citations
14 Claims
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1. In a scanner for electro-optically reading indicia by sweeping a scan spot of light along a longitudinal axis in a sweeping movement across the indicia, and by detecting light reflected off the indicia to generate an electrical signal indicative of the detected light,
an arrangement for compensating for defects in the indicia that cause reading errors, the arrangement comprising: means for dithering the scan spot during said sweeping movement by oscillating the scan spot back and forth in opposite directions across said longitudinal axis in a transverse direction generally orthogonal to said longitudinal axis to generate a dithered scan spot that creates high frequency signal components corresponding to said defects in said electrical signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. In a method of electro-optically reading indicia by sweeping a scan spot of light along a longitudinal axis in a sweeping movement across the indicia, and by detecting light reflected off the indicia to generate an electrical signal indicative of the detected light,
a method of compensating for defects in the indicia that cause reading errors, the method comprising the step of: dithering the scan spot during said sweeping movement by oscillating the scan spot back and forth in opposite directions across said longitudinal axis in a transverse direction generally orthogonal to said longitudinal axis to generate a dithered scan spot that creates high frequency signal components corresponding to said defects in said electrical signal. - View Dependent Claims (9, 10, 11, 12, 13, 14)
Specification