Illuminating assembly for use with bar code readers

• US 5,723,868 A
• Filed: 02/25/1997
• Issued: 03/03/1998
• Est. Priority Date: 05/15/1995
• Status: Expired due to Term

• Current Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Original Assignee: Welch Allyn Incorporated
• Inventors: Hammond, Charles M. Jr., Havens, William H.
• Primary Examiner(s): Le, Que
• Application Number:
  US08/805,739
• Time in Patent Office: 371 Days
• Field of Search: 250/553, 250/239, 250/221, 250/208.1, 250/208.2, 250/227.11, 250/216, 250/226, 250/227.22, 250/578.1, 362/16, 362/30, 362/277-283, 362/800, 235/473, 235/472, 235/462, 235/454
• US Class Current: 250/553
• CPC Class Codes: G06K 7/10782 Slot readers
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

An array of reflectors is arranged to approximately match the arrangement of a two-dimensional array of LEDs such as used in a 2-D bar code scanner. Each reflector has at least one reflecting wall for reflecting light from a respective LED, thus increasing the amount of LED light illuminating the target.

Claims

1. A light director for use with non-contact bar code symbol readers of the type including a two-dimensional array of light sources for illuminating a two-dimensional field of view, comprising:

a director body member including a two-dimensional array of light directing units, each of which directs light generated by a respective one of said light sources toward said two-dimensional field of view as a whole, each of said light directing units including;

(i) a first open end for receiving light generated by a corresponding light source located in proximity thereto;

(ii) a second open end through which light received into the corresponding first open end is able to pass out of said director; and

(iii) a wall extending between said first and second open ends for increasing the fraction of light passing out of said second open end, wherein light passing from said second open end of each of said light directing units impinges in an overlapping manner onto said field of view as a whole, said illuminated field of view extending a predetermined distance from said light director.

2. The light director of claim 1, in which said two-dimensional array of light sources includes a generally planar array of LEDs, and in which said light directing units are arranged in proximity to said array of LEDs, such that most of the light emitted by the LEDs enter the first open ends of correspondingly arranged light directing units.

3. The light director of claim 2, wherein said light director is spaced a predetermined distance from said array of LEDs such that a gap is formed between the open first ends of said light directing units and said array of LEDs.

4. The light director of claim 1, wherein the predetermined light impinging distance between said light director and said two-dimensional field of view allows a typical bar code symbol to fit within said two-dimensional field of view.

5. The light director of claim 1, in which said director body member has a molded one-piece construction.

6. The light director of claim 1, in which said walls each include a plurality of wall segments having different angular orientations with respect to optical axes of corresponding light sources.

7. The light director of claim 6, in which at least one of said segments of each of said walls has an angular orientation causing said at least one wall segment to intercept light rays that are emitted at angles from about 39°

to about 60°

away from the optical axes of the corresponding light sources.

8. The light director of claim 6, in which at least one of the wall segments of each of said walls has an approximately conical shape.

9. The light director of claim 6, in which at least one of the wall segments of each of said walls includes a plurality of approximately planar wall segments.

10. The light director of claim 1, wherein the intensity of light impinging on an outer portion of said two-dimensional field of view from said light director units is greater than the intensity of light impinging on an inner portion of said field of view when said director is placed the predetermined distance from said field of view.

11. In an illuminating apparatus for use in illuminating the field of view of a non-contact bar code symbol reader,:

an array of LEDs;

a generally planar substrate for supporting said array of LEDs;

a light director member, positioned in proximity to said array, defining an plurality of light directing units, each of said light directing units having;

(i) a first open end for receiving light generated by a corresponding LED;

(ii) a second open end through which light received into the first corresponding open end is directed at said field of view;

(iii) a surface disposed between said first and second open ends for concentrating light received into said first open end wherein light directed at said field of view from said light directing units impinge thereon in an overlapping manner, said illuminated field of view extending a predetermined distance from said light detector; and

means for attaching said light director member to said substrate so that most of the light emitted by each LED enters the first open end of the corresponding light directing unit.

12. The illuminating apparatus of claim 11, in which the reader is a two-dimensional bar code reader, in which said array of LEDs comprises a two-dimensional array of LEDs, and in which said field of view comprises a two-dimensional field of view.

13. The illuminating apparatus of claim 11, in which the first open ends of said light directing units are separated from said LEDs by a gap having a width selected so that relatively large fractions of the light emitted by said LEDs enter said first open ends.

14. The illuminating apparatus of claim 11, in which the dimensions of said light directing units are selected so that, when said reader is located at a typical distance from the bar code symbol to be read, said bar code symbol falls within said field of view.

15. The illuminating apparatus of claim 11, in which said light director member has a molded one-piece construction.

16. The illuminating claim 11, in which said surfaces each include a plurality of surface segments having different angular orientations with respect to optical axes of corresponding LEDs.

17. The illuminating apparatus of claim 16, in which at least one of the surface segments of each of said surfaces has an angular orientation causing said at least one surface segment to receive light rays that are formed at angles from about 39 to about 60 with respect to the optical axes of the corresponding LEDs.

18. The illuminating apparatus of claim 16, in which at least one of the surface segments of each of said surfaces has an approximately conical shape.

19. The illuminating apparatus of claim 16, in which at least one of the surface segments of each of said surfaces includes a plurality of approximately planar component segments.

20. The illuminating apparatus of claim 11, wherein the intensity of light impinging on an outer portion of said two-dimensional field of view from said light director units is greater than the intensity of light impinging on an inner portion of said field of view when said director is placed the predetermined distance from said field of view.