Imaging module for optical reader comprising refractive diffuser

• US 6,601,768 B2
• Filed: 03/08/2001
• Issued: 08/05/2003
• Est. Priority Date: 03/08/2001
• Status: Expired due to Term

• Current Assignee: Welch Allyn Incorporated
• Original Assignee: Welch Allyn Incorporated
• Inventors: Havens, William H., Hunter, Vivian L., Barber, Charles P., McCall, Melvin D., Hennick, Robert J., Coleman, Eric, Ehrhart, Michael
• Primary Examiner(s): Lee, Michael G.
• Assistant Examiner(s): Kim, Ahshik
• Application Number:
  US09/802,579
• Publication Number:
  US 20020125322A1
• Time in Patent Office: 880 Days
• Field of Search: 235/462.24, 235/462.01, 235/472.01, 235/462.42
• US Class Current: 235/462.42
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10742 including a diffuser for diffusing the light from the light source to create substantially uniform illumination of the target record carrier
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners
• CPC Class Codes: H05K 1/189 characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence

Abstract

The present invention is an imaging module including various optical components and a circuit board, which, in one embodiment, carries essentially an entirety of illumination and aiming LEDs of the module. The module includes a combination of features which result in the size of the module being reduced. The module may comprise a refractive optic diffuser plate manufactured using a textured surface mold.

Claims

1. An illumination system for an optical reader, said illumination system comprising:

a plurality of light emitting diodes; and

an optical member positioned forward of said plurality of light emitting diodes, said optical member having a diffuser surface formed thereon, wherein said diffuser surface comprises microlenses adapted to diffuse light substantially via refractive optics;

wherein said microlenses comprise a plurality of cylindrical microlenses formed in randomized dimensions on said optical member, and wherein said microlenses have randomized dimensions on the order of from about 0.018″

apex-to-apex spacing to about 0.028″

apex-to-apex spacing.

2. A The illumination system of claim 1, wherein said plurality of light emitting diodes comprise at least one vertically oriented column of light emitting diodes, and wherein said diffuser surface comprises substantially vertically oriented substantially cylindrical microlenses for diffusing light substantially horizontally with respect to said substantially cylindrical microlenses.

3. The illumination system of claim 1, wherein said plurality of light emitting diodes comprising at least one horizontally oriented row of spaced apart light sources and wherein said diffuser surface comprises substantially horizontally oriented substantially cylindrical microlenses for vertically diffusing light transmitted through said optical member.

4. The illumination system of claim 1, wherein said plurality of light emitting diodes comprise a plurality of vertically arranged columns of light sources, and wherein said diffuser surface comprises vertically oriented substantially cylindrical microlenses for diffusing light substantially horizontally with respect to said substantially cylindrical microlenses.

5. The illumination system of claim 1, wherein said microlenses are formed substantially throughout a surface of said optical member.

6. The illumination system of claim 1, wherein said microlenses are formed in randomized dimensions on said optical member.

7. The illumination system of claim 1, wherein said microlenses comprise a plurality of cylindrical microlenses.

8. The illumination system of claim 1, wherein said microlenses comprise a plurality of cylindrical microlenses delimited by valleys, and wherein said optical member includes at least one cross-connection defined in said member.

9. The illumination system of claim 8, wherein said at least one cross-connection is a plurality of cross-connections.

10. The illumination system of claim 8, wherein said at least one cross-connection connects an adjacent pair of said valleys.

11. The illumination system of claim 8, wherein said microlenses are formed substantially throughout an entire surface of said optical member.

12. An illumination system for an optical reader, said illumination system comprising:

a plurality of light emitting diodes; and

an optical member positioned forward of said plurality of light emitting diodes, said optical member having a diffuser surface formed thereon and at least one wedge for directing light from any of said light emitting diodes to a corner of a target area;

wherein said diffuser surface comprises a plurality of cylindrical microlenses delimited by a plurality of valleys, there being at least one cross-connection connecting pair of said valleys.

13. The illumination system of claim 12, wherein said diffuser surface comprises refractive optic microlenses.

14. The illumination system of claim 12, wherein said diffuser surface comprises randomized dimensioned microlenses.

15. The illumination system of claim 12, wherein said diffuser surface comprises a plurality of randomized dimensioned cylindrical microlenses.

16. The illumination system of claim 15, wherein said randomized dimensioned cylindrical microlenses are formed throughout substantially an entire surface of said optical member.

17. The illumination system of claim 12, wherein said plurality of cylindrical microlenses are formed substantially throughout an entire surface of said optical member.

18. The illumination system of claim 12, wherein said plurality of microlenses are randomized dimensioned cylindrical microlenses.

19. An imaging module comprising:

an image sensor;

at least one light source for illuminating at least part of a target area; and

an optical member having a diffuser surface formed thereon positioned optically forwardly of said at least one light source, said diffuser surface comprising a plurality of randomized dimensioned cylindrical microlenses;

wherein said randomized dimensions of said plurality of cylindrical microlenses range on the order of from about 0.018″

apex-to-apex spacing to about 0.028″

apex-to-apex spacing.

20. The imaging module of claim 19, wherein said at least one light source is a plurality of light emitting diodes.

21. The imaging module of claim 19, wherein said plurality of cylindrical microlenses are delimited by valleys, and wherein said optical member includes at least one cross-connection defined in a said member.

22. The imaging module of claim 19, further comprising a common circuit board commonly carrying said at least one light source and said image sensor.

23. An imaging module comprising:

an image sensor;

at least one light source for illuminating at least part of a target area; and

an optical member having a diffuser surface formed thereon positioned optically forwardly of said at least one light source, said diffuser surface comprising a plurality of cylindrical micro lenses delimited by a plurality of valleys, wherein said optical member further includes at least one cross-connection defined in said optical member.

24. The imaging module of claim 23, wherein said at least one cross-connection is a plurality of cross-connections there being at least one cross- connection defined in a plurality of said valleys.

25. The imaging module of claim 23, wherein said cylindrical microlenses are randomized dimensioned cylindrical microlenses.

26. the imaging module of claim 25, wherein said randomized dimensioned cylindrical microlenses are dimensioned on the order of from about 0.018″

to about 0.028″

apex-to-apex distance.

27. The imaging module of claim 23, wherein said at least one light source is a plurality of light emitting diodes.

28. The imaging module of claim 23, wherein said imaging module includes a common circuit board commonly carrying both of said at least one light source and said image sensor.

29. The imaging module of claim 23, wherein said at least one cross-connection connects a pair of said valleys.

30. An illumination system for an optical reader, said illumination system comprising:

a plurality of light emitting diodes; and

an optical member positioned forward of said plurality of light emitting diodes, said optical member having a diffuser surface formed thereon, wherein said diffuser surface comprises microlenses adapted to diffuse light substantially via refractive optics;

wherein said microlenses comprise a plurality of cylindrical microlenses delimited by valley, and wherein said optical member includes at least one cross-connection defined in said member.

31. The illumination system of claim 30, wherein said plurality of light emitting diodes comprise at least one vertically oriented column of light emitting diodes, and wherein said diffuser surface comprises substantially vertically oriented substantially cylindrical microlenses for diffusing light substantially horizontally with respect to said substantially cylindrical microlenses.

32. The illumination system of claim 30, wherein said plurality of light emitting diodes comprising at least one horizontally oriented row of spaced apart light sources and wherein said diffuser surface comprises substantially horizontally oriented substantially cylindrical microlenses for vertically diffusing light transmitted through said optical member.

33. The illumination system of claim 30, wherein said plurality of light emitting diodes comprise a plurality of vertically arranged columns of light sources, and wherein said diffuser surface comprises vertically oriented substantially cylindrical microlenses for diffusing light substantially horizontally with respect to said substantially cylindrical microlenses.

34. The illumination system of claim 30, wherein said microlenses are formed substantially throughout a surface of said optical member.

35. The illumination system of claim 30, wherein said microlenses are formed in randomized dimensions on said optical member.

36. The illumination system of claim 30, wherein said microlenses comprise a plurality of cylindrical micro lenses.

37. The illumination system of claim 30, wherein said microlenses comprise a plurality of cylindrical microlenses formed in randomized dimensions on said optical member.

38. The illumination system of claim 37, wherein said microlenses have randomized dimensions on the order of from about 0.018″

to about 0.028″

apex-to-apex spacing.

39. The illumination system of claim 30, wherein said at least one cross-connection is a plurality of cross-connections.

40. The illumination system of claim 30, wherein said at least one cross-connection connects an adjacent pair of said valleys.

41. The illumination system of claim 30, wherein said microlenses are formed substantially throughout an entire surface of said optical member.