Light pipe illumination system and method

• US 8,342,405 B2
• Filed: 11/11/2011
• Issued: 01/01/2013
• Est. Priority Date: 10/24/2003
• Status: Active Grant

• Current Assignee: Cognex Technology & Investment Corporation (Cognex Corporation)
• Original Assignee: Cognex Technology & Investment Corporation (Cognex Corporation)
• Inventors: Gerst, Carl W. III, Testa, Justin, Nadabar, Sateesh, Equitz, William H.
• Primary Examiner(s): TRAIL, ALLYSON NEEL
• Application Number:
  US13/294,286
• Publication Number:
  US 20120118967A1
• Time in Patent Office: 417 Days
• Field of Search: 235/455, 235/472.01, 235/472.02, 235/462.42, 385/43, 250/234, 710/300
• US Class Current: 235/455
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type
• CPC Class Codes: G06K 2007/10485 Arrangement of optical elements
• CPC Class Codes: G06K 2207/1011 Aiming
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/1404 Methods for optical code recognition

Abstract

Systems and methods provide for illuminating a subject using a light pipe that transmits light from a source. A method includes providing a light pipe, the light pipe defining an inner lumen through which the image sensor views the subject; providing a light source in alignment with a proximal portion of the light pipe; and using the light source, projecting a light into the light pipe and through the light pipe, the light pipe including a distal portion for providing a high-angle bright field illumination pattern on the subject with a first portion of the light and for reflecting a second portion of the light for providing a low-angle dark field illumination pattern on the subject.

Claims

1. A method for illuminating a subject, the method comprising:

providing a light pipe, the light pipe defining an inner lumen through which the image sensor views the subject;

providing a light source in alignment with a proximal portion of the light pipe; and

using the light source, projecting a light into the light pipe and through the light pipe, the light pipe including a distal portion for providing a high-angle bright field illumination pattern on the subject with a first portion of the light and for reflecting a second portion of the light for providing a low-angle dark field illumination pattern on the subject.

2. The method according to claim 1 further including providing an image sensor for imaging the subject.

3. The method according to claim 1 wherein the light pipe and the light source are each mounted on a handheld scanning appliance.

4. The method according to claim 1 further including providing a set of light sources that each project a beam at a predetermined point with respect to the subject to thereby assist aiming of an image sensor at the subject.

5. The method according to claim 1 wherein the light pipe is cylindrical, rectangular, or oval.

6. The method according to claim 1 wherein the light pipe defines a curved shape.

7. The method according to claim 1 wherein the light pipe defines a shape conforming to dimensions of the subject.

8. The method according to claim 1 further including providing an electronic controller for selectively controlling predetermined portions of the light source and providing selective illumination to portions of the light pipe.

9. A method for illuminating a subject that is imaged by an image sensor, the method comprising:

providing a first ring light source arranged around a perimeter of a predetermined shape, the first ring light source projecting light into a first light pipe defining a hollow tube having a cross-section with the predetermined shape, the first light pipe defining an inner lumen through which the image sensor views the subject and the light pipe including a tip for projecting a low-angle dark field illumination pattern on the subject; and

providing an electronic controller, the electronic controller selectively controlling predetermined portions of the first ring light source for projecting a variable light around the perimeter.

10. The method according to claim 9 wherein the predetermined shape defines a circle or a rectangle.

11. The method according to claim 9 wherein the predetermined shape defines a curved shape.

12. The method according to claim 9 wherein the predetermined shape defines a shape conforming to dimensions of a predetermined subject.

13. The method according to claim 9 wherein the first light pipe and the first ring light source are each mounted on a handheld scanning appliance.

14. The method according to claim 13 further including providing at least one light sources that projects a beam at a predetermined point with respect to the subject to thereby assist aiming of the image sensor at the subject.

15. A method for illuminating a subject that is imaged by an image sensor, the method comprising:

providing a ring light source arranged around a perimeter of a predetermined shape, the ring light source projecting light into a light pipe defining a hollow tube having a cross-section with the predetermined shape, the light pipe defining an inner lumen through which the image sensor views the subject and the light pipe including a tip to project a high-angle bright field illumination pattern with respect to the subject.

16. The method according to claim 15 wherein predetermined shape defines a circle or a rectangle.

17. The method according to claim 15 wherein the perimeter of the predetermined shape defines a shape that reduces a field of view of the image sensor.

18. The method according to claim 15 wherein the predetermined shape defines a shape conforming to dimensions of a predetermined subject.

19. The method according to claim 15 wherein the light pipe and the ring light source are each mounted on a handheld scanning appliance.

20. The method according to claim 15 further including providing set of light sources that each project a beam at a predetermined point with respect to the subject to thereby assist aiming of the image sensor at the subject.

21. A method for illuminating a subject that is imaged by an image sensor, the method comprising:

providing a first ring light source arranged around a perimeter of a predetermined shape, the first ring light source projecting light into a first light pipe defining a hollow tube having a cross-section with the predetermined shape, the first light pipe defining an inner lumen through which the image sensor views the subject and the light pipe including a tip to project a low-angle dark field illumination pattern on the subject; and

providing a bright field illuminator located external to the light pipe.

22. The method according to claim 21 wherein the bright field illuminator comprises a ring coaxial with the light pipe.