Imaging and illumination optics assembly

• US 5,780,834 A
• Filed: 05/14/1996
• Issued: 07/14/1998
• Est. Priority Date: 05/15/1995
• Status: Expired due to Term

• Current Assignee: Welch Allyn Data Collection Inc (Welch Allyn Incorporated)
• Original Assignee: Welch Allyn Incorporated
• Inventors: Onori, Tanya A., Havens, William H., Hennick, Robert J., Karpen, Thomas W., Hinkley, Robert C., Wood, Robert J. Sr., Hammond, Charles M. Jr.
• Primary Examiner(s): PITTS, HAROLD I
• Application Number:
  US08/649,126
• Time in Patent Office: 791 Days
• Field of Search: 235/454, 235/472, 235/455
• US Class Current: 235/462.1
• CPC Class Codes: G06K 7/10782 Slot readers
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

A low profile optical unit for use in a 2D bar code reader. A vertically disposed light redirecting panel having contoured reflective openings therein is mounted in the front of the unit and an LED behind the panel. Light emitting diodes for illuminating a target are mounted on the LED board behind the contour openings whereby direct light and reflected light illuminates a target. An imager housing is mounted on the back of the LED board and contains a recess that passes through the back of the housing and a lens barrel that extends forward through holes provided in the LED board and the light redirecting panel. An imager board is secured to the back of the housing which holds a 2D imager that is contained within the housing recess. Circuitry for generating image data signals is mounted on the back of the imager board. A lens holder is threadably mounted in the lens barrel which contains a lens system having a short back focal length for focusing a target image on the imager.

Claims

1. A low profile optical unit for use in an optical reader which has illumination and optical axes that are generally parallel to one another, and which is adapted to illuminate and read target indicia that are disposed in target regions that are oriented roughly perpendicular to said axes including, in combination:

a plurality of low profile LEDs for emitting light;

a light redirecting panel having a front face and a back face and having a plurality of contoured openings passing therethrough, said contoured openings having light reflecting surfaces for receiving light emitted by respective LEDs and directing said light toward said target region;

an LED board mounted in parallel alignment with said panel behind the back face of said panel for supporting said LEDs in proximity to respective ones of said openings;

an imager housing including a recessed chamber that opens through the back of said housing and a hollow lens barrel extending forward of said recessed chamber through coaxially aligned holes in said panel and said LED board;

an imager board mounted in parallel alignment with said panel and said LED Board and having a solid state two dimensional (2D) imager mounted on the front face thereof, said imager board being secured to said housing with said 2D imager positioned in said recessed chamber; and

a lens assembly disposed in said lens barrel for focusing an illuminated image of said target region upon said 2D imager;

wherein said light redirecting panel, said LED board, and said imager board are all oriented generally perpendicular to said axes, and are located in such proximity to one another that the dimensions of said optical unit in directions parallel to said axes are small in relation to the dimensions of said unit in directions perpendicular to said axes.

2. The low profile optical unit of claim 1 wherein each of said openings is so shaped that light directed thereby impinges in an overlapping manner onto said target region as a whole.

3. The low profile optical unit of claim 1 wherein the distance between the back face of said panel and the front face of said LED board is approximately equal to the height of said LEDs.

4. The low profile optical unit of claim 1 further including sealing means for forming a light seal between the front face of the imager board and the back of said housing.

5. The low profile optical unit of claim 1 further including at least one aiming light mounted in a recess formed in the light redirecting panel adjacent to the lens assembly for providing an aiming beam without increasing the length of said unit in a direction parallel to said axes.

6. The low profile optical unit of claim 1 further including at least one aiming light, in which said light redirecting panel and said LED board define a recessed seat which allows said aiming light to be included within said optical unit without increasing the length of said unit in a direction parallel to said axes.

7. The low profile optical unit of claim 1 which the distal end of the most distal one of said barrel and said lens assembly is approximately coplanar with the front face of the light redirecting panel.

8. The low profile optical unit of claim 1 further including a mother board having circuitry for storing and decoding image data produced by said 2D imager, in which said low profile optical unit is adapted to be mounted on and perpendicular to the front portion of said mother board, and in which said 2D imager is electrically connected to said storing and decoding circuitry.

9. A low profile optical unit for use in a 2D bar code reader which has illumination and optical axes that are generally parallel to one another, and which is adapted to illuminate and read a 2D bar code that is located in generally planar target region that is oriented roughly perpendicular to said axes including, in combination:

a LED board having a plurality of LEDs mounted on said board for emitting light toward a target region situated in front of said board;

an imager housing secured to the LED board, said housing containing a recessed chamber and a hollow lens barrel extending forward of said recessed chamber toward said target region;

an imager board secured to the back of said imager housing in substantial parallel alignment with said LED board, said imager board having a solid state imager mounted on the front face thereof within said recessed chamber of said imager housing, wherein the entirety of said imager housing extends forward of said imager board; and

a lens system mounted in said barrel having at least one lens element for focusing an image of said target region upon said imager;

wherein said LED board and said imager board are oriented generally perpendicular to said axes, and are located in such proximity to one another that the dimensions of said optical unit in directions parallel to said axes are small in relation to the dimensions of said unit in directions perpendicular to said axes.

10. The low profile optical unit of claim 9 in which said LED board and said imager board are coplanar.

11. The low profile optical unit of claim 9 in which the distal end of the most distal one of said barrel and said lens assembly is approximately coplanar with the distal ends of said LEDs.

12. The low profile optical unit of claim 9 in which the distal ends of the LEDs are mounted in a region bounded by a first plane in which the image recording face of the imager lies, and a second parallel plane in which the distal end of the most distal one of said barrel and said lens assembly lies.

13. The low profile optical unit of claim 9 further including at least one aiming light mounted in a recess in said optical unit adjacent to the lens assembly for providing an aiming beam.

14. The low profile optical unit of claim 9 further including at least one aiming light, in which said LED board defines a recessed seat which allows said aiming light to be included within said optical unit without increasing the length of said unit in directions parallel to said axes.

15. The low profile optical unit of claim 9 further including a mother board having circuitry for storing and decoding image data produced by said imager, in which said low profile optical unit is adapted to be mounted on and perpendicular to the front portion of said mother board, and in which said imager is electrically connected to said storing and decoding circuitry.

16. The low profile optical unit of claim 9 wherein said imager housing is a one-piece unit.

17. The low profile optical unit of claim 9 further including a light seal disposed between said imager board and said housing.