Integrated illumination assembly for symbology reader

• US 9,536,124 B1
• Filed: 04/10/2015
• Issued: 01/03/2017
• Est. Priority Date: 10/24/2003
• Status: Active Grant

• Current Assignee: Cognex Corporation
• Original Assignee: Cognex Corporation
• Inventors: Equitz, William H, Nunnink, Laurens
• Primary Examiner(s): Trail, Allyson
• Application Number:
  US14/683,622
• Time in Patent Office: 634 Days
• Field of Search: 235/455, 235/462.42, 235/462.01, 235/462.45
• US Class Current: 1/1
• CPC Class Codes: G02B 6/0096 the lights guides being of the hollow type
• CPC Class Codes: G06K 7/10584 Source control
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: G06K 7/1452 detecting bar code edges
• CPC Class Codes: G06K 7/146 the method including quality enhancement steps

Abstract

Systems and methods provide an illumination assembly for a mark reader. A light transmitter is arranged in a surrounding relationship to an interior area, with the light transmitter having a proximal end and a distal end. An illumination source provides a light for transmission into the light transmitter. The light transmitter distal end allows the light from within the light transmitter to pass through and out of the distal end to provide bright field illumination and dark field illumination. The light transmitter distal end may include a first portion and a second portion, where light from within the light transmitter passes through and out of the first portion to provide bright field illumination, and light from within the light transmitter passes through and out of the second portion to provide dark field illumination.

Claims

1. An illumination assembly for a mark reader disposed along an optical viewing axis comprising:

a light pipe defined by at least four adjacent sides including a first opposing pair of sides and a second opposing pair of sides, the light pipe including a chamfered edge at a distal end that directs light from a ring light source at the proximal end onto a surface as dark field; and

wherein a first spacing between the first opposing pair of the sides has a length different than a length of a second spacing between the second opposing pair of the sides.

2. The illumination assembly as set forth in claim 1 wherein the first opposing pair of sides and the second opposing pair of sides define collectively an approximate shape of an ellipse.

3. The illumination assembly as set forth in claim 1 wherein at least one of the first opposing pair of sides and the second opposing pair of sides define curvilinear arcs.

4. The illumination assembly as set forth in claim 1 wherein both of the first opposing pair of sides and the second opposing pair of sides define curvilinear arcs.

5. The illumination assembly as set forth in claim 1 wherein the first opposing pair of sides and the second opposing pair of sides collectively define a rectangle having corners between adjacent sides.

6. The illumination assembly as set forth in claim 5 wherein the corners are rounded.

7. An illumination assembly for a mark reader disposed along an optical viewing axis comprising:

a light pipe defined by at least four sides including at least a first opposing pair of sides and a second opposing pair of sides, the light pipe including a chamfered edge at a distal end that directs light from a light source at the proximal end through the chamfered edge onto a surface as dark field light rays; and

wherein the convergence distance of the dark field light rays for the at least first opposing pair of sides is less than the convergence distance of the dark field light rays for the at least second opposing pair of sides.

8. The illumination assembly as set forth in claim 7 wherein a first spacing between the at least first opposing pair of the sides has a first length different than a second length of a second spacing between the at least second opposing pair of the sides.

9. The illumination assembly as set forth in claim 7 further including a third opposing pair of sides.

10. The illumination assembly as set forth in claim 7 where the chamfered edge is an exterior wall at the distal end.

11. An illumination assembly for a mark reader disposed along an optical viewing axis comprising:

a rectangular light pipe defined by a set of linear or non-linear sides that intersect at each of four corners that cause the approximate direction of two adjacent sides to vary by substantially ninety degrees;

a light source at a proximal end of the rectangular light pipe to direct light through a distal end of the rectangular light pipe onto a surface as dark field light rays; and

wherein the dark field light rays from the set of linear or non-linear sides that intersect at each of four corners converge at at least two differing distance ranges of the dark field light rays onto the surface.

12. The illumination assembly as set forth in claim 11 wherein the rectangular light pipe includes a chamfered edge at the distal end that directs the light from the light source through an interior edge onto the surface as the dark field light rays.

13. The illumination assembly as set forth in claim 11 wherein the set of linear or non-linear sides that intersect at each of four corners includes at least four sides including at least a first opposing pair of sides and a second opposing pair of sides.

14. The illumination assembly as set forth in claim 13 wherein a convergence distance of the dark field light rays for the at least first opposing pair of sides is less than a convergence distance of the dark field light rays for the at least second opposing pair of sides.