Low profile illumination for direct part mark readers

• US 7,823,789 B2
• Filed: 12/21/2004
• Issued: 11/02/2010
• Est. Priority Date: 12/21/2004
• Status: Expired due to Fees

• Current Assignee: Cognex Technology & Investment Corporation (Cognex Corporation)
• Original Assignee: Cognex Technology & Investment Corporation (Cognex Corporation)
• Inventors: Nunnink, Laurens
• Primary Examiner(s): Kim; Ahshik
• Application Number:
  US11/019,763
• Publication Number:
  US 20060131419A1
• Time in Patent Office: 2,142 Days
• Field of Search: 235/472.01, 235/462.25, 235/462.42, 235/462.43, 235/42.25
• US Class Current: 235/472.01
• CPC Class Codes: G06K 7/10732 Light sources

Abstract

An industrial reader is provided with an image formation system that is particularly adapted to read bar codes and two-dimensional symbols marked directly on objects. The image formation system includes illumination sources and illumination transmissive components that produce a combination of bright field and dark field illumination.

Claims

1. An industrial identification mark reader comprising:

a housing;

an imaging module positioned within the housing to capture an image of a mark on an object placed before the reader;

an illuminator module comprising a plurality of illuminators mounted within the housing wherein subsets of the illuminators are separately actuatable; and

an integrated optical transmitter mounted within the housing, the integrated optical transmitter having separate dark and bright field illuminator transmitters, the dark and bright field illumination transmitters simultaneously optically aligned with at least first and second different ones of the plurality of illuminators, the dark field illumination transmitter changing the direction of light from the first illuminator to thereby project dark field illumination at the object, the bright field illumination transmitter projecting bright field illumination at the object when the second illuminator is actuated.

2. The reader according to claim 1 wherein the integrated optical transmitter is a removable component.

3. The reader according to claim 1 wherein the dark field illumination transmitter is a light pipe.

4. The reader according to claim 3 wherein the bright field illumination transmitter is positioned within the light pipe.

11. The reader according to claim 4 wherein the integrated optical transmitter is a removable component.

18. The reader of claim 1 wherein the optical transmitter is formed of molded plastic.

19. The reader of claim 1 wherein the optical transmitter further includes a window.

20. The reader of claim 1 wherein the bright field illumination transmitter includes at least one lens.

22. The reader of claim 1 wherein the bright and dark field illumination transmitters are formed as a single component including separate dark and bright field illuminators.

5. A plastic molded optical transmitter for use in a direct part mark reader that includes first and second different pluralities of illuminators, the transmitter comprising:

an integrated optical transmitter including;

at least one dark field illumination transmitter that changes the direction of light entering the dark field illumination transmitter to project light at an object; and

at least one bright field illumination transmitter adjacent to and separate from the dark field illumination transmitter that projects light at the object;

wherein, the dark and bright field illumination transmitters are juxtaposed with respect to each other so that when the dark field illumination transmitters are optically aligned with the first plurality of illuminators, the bright field illumination transmitters are optically aligned with the second plurality of illuminators and the dark field illuminators are optically misaligned with the bright field illuminators.

6. The transmitter according to claim 5 wherein the dark field illumination transmitter, and the at least one bright field transmitter is composed of an injection molded clear plastic material.

7. The transmitter according to claim 6 wherein the injection molded clear plastic material is polymethyl methacrylate.

8. The transmitter according to claim 5, further comprising a window.

9. The transmitter according to claim 8 wherein the window comprises an optical filter.

12. The reader transmitter according to claim 5 wherein the dark field illumination transmitter is a light pipe and the bright field illumination transmitter is positioned within the light pipe.

23. The transmitter of claim 5 wherein the bright and dark field illumination transmitters are formed as a single component including separate dark and bright field illuminators.

10. A hand-held direct part mark reader comprising:

a housing;

an imaging module having a field of view, the imaging module mounted within the housing for capturing an image of a mark on an object place in the field of view;

an illuminator module comprising a plurality of selectively actuated illuminators, the illuminator module mounted within the housing;

a dark field illumination transmitter, in optical cooperation with at least one of the plurality of selectively actuated illuminators in the illuminator module to project dark field illumination on the object, the dark field transmitter mounted within the housing and circumferentially surrounding a window through which reflected light from the field of view passes to the imaging module; and

a viewing port through the housing to permit direct observation of the field of view through the window.

13. The reader according to claim 10 further including a bright field illumination transmitter in optical cooperation with as least one of the plurality of illuminators in the illumination module to project bright field illumination on the object, the bright field illumination transmitter mounted within the housing.

14. The reader of claim 13 wherein the dark field illumination transmitter is a light pipe and the bright field illumination transmitter is positioned within the light pipe.

15. The reader according to claim 14 wherein the integrated optical transmitter is a removable component.

16. The reader of claim 13 wherein the bright field illumination transmitter includes at least one lens.

17. The reader of claim 13 wherein the dark field illumination transmitter and the bright field illumination transmitter are each formed of molded plastic.

21. The reader of claim 10 wherein the dark field illumination transmitter is annular and the viewing port passes through the dark field illumination transmitter.