Method of and system for profile equalization employing visible laser diode (VLD) displacement

• US 7,395,971 B2
• Filed: 09/02/2005
• Issued: 07/08/2008
• Est. Priority Date: 11/24/2000
• Status: Expired due to Fees

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Zhu, Xiaoxun, Knowles, C. Harry, Schnee, Michael
• Primary Examiner(s): Kim; Ahshik
• Application Number:
  US11/219,382
• Publication Number:
  US 20060000909A1
• Time in Patent Office: 1,040 Days
• Field of Search: 235/462.32, 235/462.22, 235/462.23, 235/462.25, 235/462.42
• US Class Current: 235/462.32
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G02B 27/0961 Lens arrays lens arrays per se G02B3/0006
• CPC Class Codes: G02B 27/0966 Cylindrical lenses cylindrical lenses per se G02B3/06
• CPC Class Codes: G06K 7/10732 Light sources

Abstract

A method of equalizing the illumination produced by a planar laser illumination array within a planar laser illumination and (electronic) imaging system, comprising the steps of: providing an image formation and detection module having imaging optics with a field of view (FOV) focused upon an image detecting array; providing a planar laser illumination array having a plurality of planar laser illumination modules, each planar laser illumination module producing a planar laser beam component during image formation and detection operations, which are combined to produce a composite planar laser illumination beam extending through a working range of said FOV, wherein said working range includes both near and far fields, if the near field illumination is brighter then the far field illumination: displacing a first portion of the planar illumination modules in a first direction perpendicular to said FOV and a second portion of the planar illumination modules in a second direction opposite to said first direction, angling each planar laser illumination beam component to overlap at said far field, whereby the power density incident on the near field is reduced; and if the far field illumination is brighter then the near field illumination: displacing a first portion of the planar illumination modules in a first direction perpendicular to the FOV and a second portion of the planar illumination modules in a second direction opposite to said first direction, angling each planar laser illumination beam component to overlap at the near field, whereby the power density incident on the far field is reduced.

Claims

1. A method of equalizing the illumination produced by a planar laser illumination array within a planar laser illumination and electronic imaging system, comprising the steps of:

providing an image formation and detection module having imaging optics with a field of view (FOV) focused upon an image detecting array;

providing a planar laser illumination array having a plurality of planar laser illumination modules, each planar laser illumination module producing a planar laser beam component during image formation and detection operations, which are combined to produce a composite planar laser illumination beam extending through a working range of said FOV, wherein said working range includes both near and far fields,

if the near field illumination is brighter than the far field illumination;

displacing a first portion of the planar illumination modules in a first direction perpendicular to said FOV and a second portion of the planar illumination modules in a second direction opposite to said first direction, angling each planar laser illumination beam component to overlap at said far field, whereby the power density incident on the near field is reduced; and

if the far field illumination is brighter than the near field illumination;

displacing a first portion of the planar illumination modules in a first direction perpendicular to the FOV and a second portion of the planar illumination modules in a second direction opposite to said first direction, angling each planar laser illumination beam component to overlap at the near field, whereby the power density incident on the far field is reduced.

2. The method of claim 1, wherein each of said plurality of planar laser illumination modules comprises a visible laser diode (VLD), a focusing lens, and a cylindrical optical element arranged therewith to produce one of said plurality of substantially planar laser illumination beam components.

3. The method of claim 1, wherein said image formation and detection module and said planar laser illumination array are both contained in a system housing.

4. The method of claim 3, which comprises supporting said system housing above a conveyor belt structure along which the object is transported.

5. The method of claim 1, wherein said first portion of the planar illumination modules are equal in number to said second portion of the planar illumination modules.

6. The method of claim 1, wherein said first portion of the planar illumination modules are not equal in number to said second portion of the planar illumination modules.

7. A method of equalizing the illumination produced by a planar laser illumination array within a planar laser illumination and electronic imaging system, comprising the steps of:

providing an image formation and detection module having imaging optics with a field of view (FOV) focused upon an image detecting array;

providing a planar laser illumination array having a plurality of planar laser illumination modules, each planar laser illumination module producing a planar laser beam component during image formation and detection operations, which are combined to produce a composite planar laser illumination beam extending through a working range of said FOV, wherein said working range includes both near and far fields,

in response to the near field illumination being brighter than the far field illumination;

displacing a first portion of the planar illumination modules in a first direction perpendicular to said FOV and a second portion of the planar illumination modules in a second direction opposite to said first direction, aligning each planar laser illumination beam component to overlap at said far field, whereby the power density incident on the near field is reduced; and

in response to the far field illumination being brighter than the near field illumination;

displacing a first portion of the planar illumination modules in a first direction perpendicular to the FOV and a second portion of the planar illumination modules in a second direction opposite to said first direction, aligning each planar laser illumination beam component to overlap at the near field, whereby the power density incident on the far field is reduced.

8. The method of claim 7, wherein each of said plurality of planar laser illumination modules comprises a visible laser diode (VLD), a focusing lens, and a cylindrical optical element arranged therewith to produce one of said plurality of substantially planar laser illumination beam components.

9. The method of claim 7, wherein said image formation and detection module and said planar laser illumination array are both contained in a system housing.

10. The method of claim 9, which comprises supporting said system housing above a conveyor belt structure along which the object is transported.

11. The method of claim 7, wherein said first portion of the planar illumination modules are equal in number to said second portion of the planar illumination modules.

12. The method of claim 7, wherein said first portion of the planar illumination modules are not equal in number to said second portion of the planar illumination modules.

13. A planar laser illumination and electronic imaging system, said system comprising:

an image formation and detection module having imaging optics with a field of view (FOV) focused upon an image detecting array;

a planar laser illumination array having a plurality of planar laser illumination modules, each planar laser illumination module producing a planar laser beam component during image formation and detection operations, which are combined to produce a composite planar laser illumination beam extending through a working range of said FOV, wherein said working range includes both near and far fields,

means for equalizing the illumination profile produced by said planar illumination array, if said near field illumination is brighter than said far field illumination, by aligning each planar laser illumination beam component to overlap at said far field, whereby the power density incident on the near field is reduced; and

means for equalizing the illumination profile produced by said planar illumination array, if said far field illumination is brighter than said near field illumination, by aligning each planar laser illumination beam component to overlap at the near field, whereby the power density incident on the far field is reduced.

14. The system of claim 13, wherein each of said plurality of planar laser illumination modules comprises a visible laser diode (VLD), a focusing lens, and a cylindrical optical element arranged therewith to produce one of said plurality of substantially planar laser illumination beam components.

15. The system of claim 13, wherein said image formation and detection module and said planar laser illumination array are both contained in a system housing.

16. The system of claim 15, which comprises supporting said system housing above a conveyor belt structure along which the object is transported.

17. The system of claim 13, wherein said first portion of the planar illumination modules are equal in number to said second portion of the planar illumination modules.

18. The system of claim 13, wherein said first portion of the planar illumination modules are not equal in number to said second portion of the planar illumination modules.