Electro-optical scanner having selectable scan pattern

Abstract

A wavelength selector in an optical scanner is operative for selecting a first laser beam having a predetermined wavelength to produce a first scan pattern, and for selecting a second laser beam having a different wavelength to produce a second scan pattern. The scan patterns have a different number of scan lines. The selected scan pattern is scanned over indicia, e.g., a bar code symbol, to be read.

1. An optical scanner for reading indicia having parts of different light reflectivity, comprising:
 a) an optical assembly for producing a plurality of light beams of different wavelengths; and  
 b) a scan pattern generator, including a wavelength selector for selecting a first of the beams to produce a first scan pattern, and for selecting a second of the beams to produce a second scan pattern, the scan patterns having a different number of scan lines, and the scan pattern generator being operative for scanning the selected scan pattern over the indicia to be read.  
 
     
     
       2. The scanner according to  claim 1 , wherein the optical assembly includes a plurality of lasers for producing the light beams as laser beams. 
     
     
       3. The scanner according to  claim 2 , wherein the first laser beam has a wavelength of 670 nm, and wherein the second laser beam has a wavelength of 630 nm. 
     
     
       4. The scanner according to  claim 2 , wherein the optical assembly includes a plurality of optical lenses, each of the lenses being respectively associated with a respective laser, for optically modifying the respective laser beam. 
     
     
       5. The scanner according to  claim 1 , wherein the scan pattern generator includes a plurality of optical elements, each of the elements having different optical properties when the light beams of different wavelengths are incident on a respective element. 
     
     
       6. The scanner according to  claim 5 , wherein the elements are mirrors, at least one of the mirrors having a wavelength-selective coating thereon. 
     
     
       7. The scanner according to  claim 6 , wherein the coating has a predetermined thickness. 
     
     
       8. The scanner according to  claim 6 , wherein all the mirrors have the wavelength-selective coating thereon. 
     
     
       9. The scanner according to  claim 6 , wherein the coating is operative for reflecting only one of light beams. 
     
     
       10. The scanner according to  claim 5 , wherein the elements are mirrors, at least one of the mirrors being mounted for movement relative to the optical assembly. 
     
     
       11. The scanner according to  claim 10 , wherein others of the mirrors are stationarily mounted within the scanner. 
     
     
       12. The scanner according to  claim 11 , wherein the others of the mirrors are arranged along an arc. 
     
     
       13. The scanner according to  claim 5 , wherein one of the scan patterns is an omni-directional scan pattern. 
     
     
       14. The scanner according to  claim 1 , wherein the wavelength selector is operative for manually selecting one of the beams. 
     
     
       15. The scanner according to  claim 1 , wherein the wavelength selector is operative for automatically selecting one of the beams. 
     
     
       16. A method of reading indicia having parts of different light reflectivity, comprising the steps of:
 a) producing a plurality of light beams of different wavelengths;  
 b) selecting a first of the beams having a first wavelength to produce a first scan pattern, and selecting a second of the beams having a second wavelength to produce a second scan pattern, the scan patterns having a different number of scan lines.  
 
     
     
       17. The method according to  claim 16 , wherein the producing step is performed by producing the light beams as laser beams. 
     
     
       18. The method according to  claim 17 , wherein the first laser beam has a wavelength of 670 nm, and wherein the second laser beam has a wavelength of 630 nm. 
     
     
       19. The method according to  claim 16 , wherein the selecting step is performed manually. 
     
     
       20. The method according to  claim 16 , wherein the selecting step is performed automatically. 
     
     
       21. The method according to  claim 16 , wherein the selecting step is performed by providing a plurality of optical elements, each of the elements having different optical properties when the light beams of different wavelengths are incident on a respective element. 
     
     
       22. The method according to  claim 21 , wherein the elements are mirrors, and wherein the selecting step is performed by applying a wavelength-selective coating on at least one of the mirrors. 
     
     
       23. The method according to  claim 22 , wherein the applying step is performed by applying the coating on all of the mirrors. 
     
     
       24. The method according to  claim 21 , wherein the elements are mirrors, and wherein the scanning step is performed by moving at least one of the mirrors.