Illuminator for DPM scanner

• US 10,360,424 B2
• Filed: 12/15/2017
• Issued: 07/23/2019
• Est. Priority Date: 12/28/2016
• Status: Active Grant

• Current Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Original Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Inventors: Feng, Chen, Gillet, Alain, Ren, Jie, Ouyang, Yunxin, Li, Hui
• Primary Examiner(s): Hess, Daniel A
• Application Number:
  US15/843,247
• Publication Number:
  US 20180181783A1
• Time in Patent Office: 585 Days
• Field of Search: 235454, 235455, 23546201, 23546242
• CPC Class Codes: G02B 2003/0093 characterised by the shape
• CPC Class Codes: G02B 3/00 Simple or compound lenses
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/10 with curved faces
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10742 including a diffuser for diffusing the light from the light source to create substantially uniform illumination of the target record carrier
• CPC Class Codes: G06K 7/10831 Arrangement of optical elements, e.g. lenses, mirrors, prisms optical elements per se G02B
• CPC Class Codes: G06K 7/10841 Particularities of the light-sensitive elements semiconductor devices H01L
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners
• CPC Class Codes: G06K 7/1098 the scanning arrangement having a modular construction
• CPC Class Codes: H04N 1/107 with manual scanning

Abstract

A compact illuminator for a direct part marking (DPM) scanner is provided to perform dual-field, multi-color, multi-directional, multi-distance illumination functions. The illuminator can selectively provide dark field and bright field illumination with broad spectrum white or narrow band color, in combination with directions for near contact distance as well as far distance barcode readings. Specifically, illuminator includes a front edge illuminator with customized LED optics, a dome diffuser, an LED board assembly, and a reflective sleeve surrounding the dome diffuser. The board assembly can further include an alternative on/off plural point source bright field spot illuminating system. A method for scanning DPM indicia focuses on generating illumination light using an illumination assembly, illuminating the DPM indicia, detecting reflected and/or scattered light, and capturing under different illumination conditions and combining at least two consecutive images of the DPM indicia, followed by processing and decoding the obtained image.

Claims

1. An illuminator for a direct part marking (DPM) scanner, the illuminator comprising:

an imager window;

front edge illuminator optics disposed between the imager window and a region of interest, the front edge illuminator optics and imager window defining a field of view and an optical axis;

an enclosure configured to support the front edge illuminator optics at a distance defined by the field of view;

a dome diffuser coaxially aligned with the optical axis, having a front end at least partially surrounding the field of view proximate to the enclosure, and a rear end proximate to the imager window, the dome having at least two optically clear openings configured to facilitate illumination of an object under different illumination conditions to reduce specular reflection by combining a first image and a second image taken with different illumination, wherein a first image is captured with illumination via a first optically clear opening of the two optically clear openings, and a second image is captured with illumination via a second optically clear opening of the two optically clear openings;

an LED assembly coaxially aligned with the optical axis, and proximal to the rear end of the dome diffuser; and

a reflective sleeve coaxially aligned with the optical axis and at least partially surrounding the dome diffuser, having a first end operably coupled to the enclosure and a second end operably coupled to the LED assembly.

2. The illuminator according to claim 1, wherein the LED assembly comprises:

a dark field illuminating system;

a plural point source bright field spot illuminating system; and

a diffused bright field illuminating system.

3. The illuminator according to claim 1, wherein the front edge illuminator optics comprises a freeform lens.

4. The illuminator according to claim 3, wherein the freeform lens is a non-rotational symmetric optics.

5. The illuminator according to claim 1, wherein the front edge illuminator optics comprises a cylindrical optics.

6. The illuminator according to claim 1, wherein the DPM scanner comprises a portable DPM scanner.

7. The illuminator according to claim 1, wherein the dome diffuser is a superellipsoidal dome having at least two optically clear openings aligned with two spot illumination light sources generating illumination light, wherein the generated illumination light illuminates a direct part marking (DPM) indicia, wherein the superellipsoidal provides minimal surface curvature changes to reduce non-uniformity of the generated illumination light.

8. A scanner illumination assembly, comprising:

a front edge illuminator assembly operatively coupled to a customized LED optics;

a printed circuit board assembly having a front portion and a back portion, the front portion having at least six color LEDs for dark field illumination, and the back portion having at least four white and/or blue LEDs near four corners of the printed circuit board assembly, and an alternative on/off plural point source bright field spot illumination assembly;

a superellipsoidal dome having a front end operatively coupled to the front edge illuminator assembly, and a rear end having a protective window with a camera opening and operatively coupled to the printed circuit board assembly, the dome having at least two optically clear openings configured to facilitate illumination of an object under different illumination conditions to reduce specular reflection by combining images taken with different illumination, wherein a first image is captured with illumination via a first optically clear opening of the two optically clear openings, and a second image is captured with illumination via a second optically clear opening of the two optically clear openings, and a camera aimer beam opening near the rear end of the dome; and

an assembly enclosure having an inner sleeve, a front end operatively coupled to the front edge illuminator assembly, and a rear end operatively coupled to the printed circuit board assembly.

9. The scanner illumination assembly of claim 8, wherein the plural point source bright field spot illumination assembly comprises at least two spot illumination red LEDs with aspheric lens caps, the LEDs aligned with the optically clear openings in the dome.

10. The scanner illumination assembly of claim 8, wherein the front edge illuminator assembly comprises a dual-distance freeform LED lens cap with split optical design.

11. The scanner illumination assembly of claim 8, wherein the front edge illuminator assembly comprises a cylindrical optics.

12. The scanner illumination assembly of claim 11, wherein the cylindrical optics comprises at least a partial reflective and/or refractive surface.

13. The scanner illumination assembly of claim 8, wherein the printed circuit board assembly comprises a rigid-flex printed circuit board assembly.

14. The scanner illumination assembly of claim 8, wherein the inner sleeve of the assembly enclosure is at least partially covered with a reflective coating.

15. The scanner illumination assembly of claim 8, wherein the white and/or blue LEDs further comprise batwing LED lens caps disposed in front of the LEDs.

16. The scanner illumination assembly of claim 8, wherein the customized LED optics comprise polycarbonate and/or poly(methyl methacrylate) injection molded LED optics.

17. A method for scanning direct part marking (DPM) indicia, comprising:

generating illumination light using two spot illumination light sources aligned with two optically clear openings in a superellipsoidal dome in an illumination assembly operatively coupled to a DPM scanner, the at least two optically clear openings in the superellipsoidal dome being configured to facilitate illumination of an object under different illumination conditions to reduce specular reflection by combining images taken with different illumination;

illuminating the DPM indicia with the illumination light;

detecting light reflected and/or scattered from the DPM indicia to capture an image of the DPM indicia;

capturing at least two images of the DPM indicia under different illumination conditions;

combining at least two consecutive images captured under different illumination conditions, wherein a first image is captured with illumination via a first optically clear opening of the two optically clear openings, and a second image is captured with illumination via a second optically clear opening of the two optically clear openings to obtain a combined image; and

processing and decoding the combined image of the DPM indicia.

18. The method of claim 17, wherein the generating an illumination light comprises:

adjusting bright field illumination;

adjusting dark field illumination; and

/or

adjusting diffused light illumination.

19. The method of claim 18, wherein the bright field illumination adjustment comprises using at least two alternative on/off spot illumination LEDs with aspheric lens caps.

20. The method of claim 17, further including reducing the specular reflection of the DPM indicia using an edge illuminator disposed in front of the illumination assembly.