Techniques for miniaturizing bar code scanners including spiral springs and speckle noise reduction
First Claim
1. In a reader for electro-optically reading a bar code symbol, the symbol comprising bars and spaces of different light reflectivity and having specific relative widths, by sweeping a laser spot across the symbol for reflection therefrom, by detecting laser light reflected from the symbol, and by generating an analog electrical signal indicative of the laser light detected, an arrangement for reducing speckle noise influence in the analog signal, the arrangement comprising:
- a) a laser emitter for emitting a laser beam to form the laser spot on the symbol with a circular spot size having a diameter at least twice a width of a bar having the narrowest width in the symbol; and
b) a decoder including a non-differentiating digitizer for processing the analog signal into an output signal having transitions which correspond to boundaries between adjoining bars and spaces.
6 Assignments
0 Petitions
Accused Products
Abstract
Various techniques for reducing the size of bar code scanner modules are disclosed including embodiments having miniature moving mirror elements employing spiral tape springs and micro machined structures. Other embodiments employ VCSELs and relatively small collection areas, while minimizing speckle noise through beam shaping and signal processing techniques.
-
Citations
14 Claims
-
1. In a reader for electro-optically reading a bar code symbol, the symbol comprising bars and spaces of different light reflectivity and having specific relative widths, by sweeping a laser spot across the symbol for reflection therefrom, by detecting laser light reflected from the symbol, and by generating an analog electrical signal indicative of the laser light detected, an arrangement for reducing speckle noise influence in the analog signal, the arrangement comprising:
-
a) a laser emitter for emitting a laser beam to form the laser spot on the symbol with a circular spot size having a diameter at least twice a width of a bar having the narrowest width in the symbol; and
b) a decoder including a non-differentiating digitizer for processing the analog signal into an output signal having transitions which correspond to boundaries between adjoining bars and spaces. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. In a method of electro-optically reading a bar code symbol, the symbol comprising bars and spaces of different light reflectivity and having specific relative widths, by sweeping a laser spot across the symbol for reflection therefrom, by detecting laser light reflected from the symbol, and by generating an analog electrical signal indicative of the laser light detected, a method of reducing speckle noise influence in the analog signal, the method comprising the steps of:
-
a) emitting a laser beam to form the laser spot on the symbol with a circular spot size having a diameter at least twice a width of a bar having the narrowest width in the symbol; and
b) digitizing the analog signal with a non-differentiating digitizer into an output signal having transitions which correspond to boundaries between adjoining bars and spaces. - View Dependent Claims (10, 11, 12, 13, 14)
-
Specification