Barcode reader having multiple illumination systems and multiple sets of imaging optics

• US 8,864,034 B1
• Filed: 12/13/2013
• Issued: 10/21/2014
• Est. Priority Date: 07/19/2013
• Status: Expired due to Fees

• Current Assignee: The Code Corporation (Brady Corporation)
• Original Assignee: The Code Corporation (Brady Corporation)
• Inventors: Lei, Ming, Powell, George
• Primary Examiner(s): LEE, SEUNG H
• Application Number:
  US14/105,380
• Time in Patent Office: 312 Days
• Field of Search: 235/454, 235/462.06, 235/462.14, 235/462.32, 235/462.42
• US Class Current: 235/462.06
• 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 7/1465 using several successive scans of the optical code

Abstract

According to one aspect of the invention, there is provided a barcode reader, comprising a first illumination system that emits first illumination with a first illumination spectrum, and a second illumination system that emits second illumination with a second illumination spectrum. The second illumination spectrum is broader than the first illumination spectrum. The barcode reader also comprises a first lens assembly with a first optical path through the first lens assembly to a first image sensor section. The first optical path includes a first filter configured to pass an acceptance spectrum of electromagnetic radiation and attenuate an attenuated spectrum of electromagnetic radiation. The first illumination spectrum is primarily composed of the acceptance spectrum. The barcode reader also comprises a second lens assembly with second optical path through the second lens assembly to a second image sensor section.

Claims

1. A barcode reader, comprising:

a first illumination system that emits first illumination with a first illumination spectrum;

a second illumination system that emits second illumination with a second illumination spectrum, the second illumination spectrum being broader than the first illumination spectrum;

a first lens assembly with a first optical path through the first lens assembly to a first image sensor section, the first optical path including a first filter configured to pass a first filter spectrum of electromagnetic radiation and attenuate a second filter spectrum of electromagnetic radiation, wherein the first illumination spectrum is primarily composed of the first filter spectrum; and

a second lens assembly with second optical path through the second lens assembly to a second image sensor section.

2. The barcode reader of claim 1, wherein the second filter spectrum includes frequencies of visible light not included in the first illumination spectrum.

3. The barcode reader of claim 1, wherein the first illumination spectrum includes electromagnetic radiation primarily from 650 nm to 700 nm.

4. The barcode reader of claim 1, wherein the second illumination spectrum includes electromagnetic radiation primarily from 400 nm to 700 nm.

5. The barcode reader of claim 1, wherein the first illumination system is a dark field illumination system, the dark field illumination system emitting the first illumination towards the first optical path at an emission angle that is less than 45 degrees from a plane that is perpendicular to the first optical path.

6. The barcode reader of claim 5, wherein the dark field illumination system comprises a first set of illumination sources positioned to a right side of the first and second lens assemblies and a second set of illumination sources positioned to a left side of the first and second lens assemblies.

7. The barcode reader of claim 6, further comprising control circuitry that independently controls intensity of the first set of illumination sources and the second set of illumination sources.

8. The barcode reader of claim 6, wherein the dark field illumination system comprises a back lit illumination diffusor emitting the first illumination towards the first optical path at the emission angle.

9. The barcode reader of claim 6, wherein:

the dark field illumination system comprises a refracting diffusor through which the first illumination is emitted towards the first optical path at the emission angle; and

illumination enters the refracting diffusor at an entry angle that is different than the emission angle.

10. The barcode reader of claim 9, wherein the entry angle is substantially parallel to the first optical path.

11. The barcode reader of claim 9, wherein the entry angle is substantially perpendicular to the emission angle.

12. The barcode reader of claim 1, wherein the second illumination system is a diffuse bright field illumination system comprising:

an optical substrate with a front major surface and a back major surface, each of which is substantially perpendicular to an optical path of the barcode reader, the front major surface facing a field of view of the first and second lens assemblies;

at least one illumination source propagating illumination between the front major surface and the back major surface; and

extraction features causing the second illumination to exit the front major surface into the field of view of the first and second lens assemblies.

13. A barcode reader, comprising:

an image sensor configured to capture an image of a barcode within a field of view of the image sensor;

a first set of imaging optics and a second set of imaging optics, each for providing a corresponding image of the barcode on the image sensor; and

a first illumination system and a second illumination system, each for illuminating at least a part of the field of view with a respective first illumination spectrum and a second illumination spectrum different from the first illumination spectrum, wherein the first set of imaging optics and the second set of imaging optics respond differently to the different illumination spectrums.

14. The barcode reader of claim 13, further comprising a housing, wherein the first set of imaging optics and the second set of imaging optics are positioned within the housing such that there is a first optical path through the first set of imaging optics to a first portion of the image sensor and a second optical path through the second set of imaging optics to a second portion of the image sensor.

15. The barcode reader of claim 14, wherein the first optical path is different from the second optical path.

16. The barcode reader of claim 14, wherein the first portion of the image sensor corresponds to approximately a first half of the image sensor and the second portion of the image sensor corresponds to approximately a second half of the image sensor.

17. The barcode reader of claim 14, wherein the image sensor comprises a first image sensor and a second image sensor, the first image sensor including the first portion of the image sensor and the second image sensor including the second portion of the image sensor.

18. The barcode reader of claim 13, wherein the first set of imaging optics includes a filter configured to pass a first filter spectrum of electromagnetic radiation and attenuate a second filter spectrum of electromagnetic radiation.

19. The barcode reader of claim 18, wherein the first illumination spectrum includes the first filter spectrum.

20. The barcode reader of claim 18, wherein the first illumination spectrum is primarily composed of the first filter spectrum.

21. The barcode reader of claim 18, wherein the second filter spectrum includes frequencies of visible light not included in the first illumination spectrum.

22. The barcode reader of claim 18, wherein the first illumination spectrum includes electromagnetic radiation primarily from 650 nm to 700 nm.

23. The barcode reader of claim 18, wherein the second illumination spectrum includes electromagnetic radiation primarily from 400 nm to 700 nm.

24. The barcode reader of claim 13, wherein:

the first illumination system includes a bright field illumination system that directs bright field illumination having the first illumination spectrum into the field of view of the image sensor;

the first illumination system also includes a dark field illumination system that directs dark field illumination into the field of view of the image sensor; and

the second illumination system includes a diffuse bright field illumination system that directs diffuse bright field illumination having the second illumination spectrum into the field of view of the image sensor.

25. The barcode reader of claim 24, wherein the bright field illumination system and the diffuse bright field illumination system direct illumination into the field of view of the image sensor substantially parallel to an optical path that runs through a set of imaging optics to a portion of the image sensor.

26. A barcode reader, comprising:

a first illumination system that emits illumination with a first illumination spectrum;

a second illumination system that emits illumination with a second illumination spectrum;

an image sensor configured to capture an image of a barcode within a field of view of the image sensor; and

a first set of imaging optics and a second set of imaging optics, each providing a corresponding image of the barcode on the image sensor;

wherein the first set of imaging optics is configured to focus an image of the barcode, when illuminated by the first illumination system, with a superior contrast profile than when illuminated by the second illumination system;

wherein the second set of imaging optics is configured to focus an image of the barcode, when illuminated by the second illumination system, with a superior contrast profile than when illuminated by the first illumination system; and

wherein superior contrast profile means at least one of;

(i) greater maximum amplitude between the portions of the image that are dark marks of the barcode and the portions of the image that are light marks of the barcode; and

(ii) more distinct transitions between portions of the image that are dark marks of the barcode and the portions of the image that are light marks of the barcode.

27. The barcode reader of claim 26, wherein the first illumination system is a dark field illumination system, the dark field illumination system emitting the illumination of the first illumination spectrum into the field of view of the image sensor at an angle that is less than 45 degrees from a plane that is perpendicular to an optical path from the image sensor through the first set of imaging optics into a center of a field of view of the first set of imaging optics.

28. The barcode reader of claim 27, wherein the dark field illumination system comprises a first set of illumination sources positioned to a right side of the first and second sets of imaging optics and a second set of illumination sources positioned to a left side of the first and second sets of imaging optics.

29. The barcode reader of claim 28, further comprising control circuitry that independently controls intensity of the first set of illumination sources and the second set of illumination sources.

30. The barcode reader of claim 28, wherein the dark field illumination system comprises a back lit illumination diffusor emitting the first illumination towards the first optical path at the emission angle.

31. The barcode reader of claim 28, wherein:

the dark field illumination system comprises a refracting diffusor through which the first illumination is emitted towards the first optical path at the emission angle; and

illumination enters the refracting diffusor at an entry angle that is different than the emission angle.

32. The barcode reader of claim 31, wherein the entry angle is substantially parallel to the first optical path.

33. The barcode reader of claim 31, wherein the entry angle is substantially perpendicular to the emission angle.

34. The barcode reader of claim 26, wherein the second illumination system is a diffuse bright field illumination system comprising:

an optical substrate with a front major surface and a back major surface, each of which is substantially perpendicular to an optical path of the barcode reader, the front major surface facing a field of view of the first and second lens assemblies;

at least one illumination source propagating illumination between the front major surface and the back major surface; and

extraction features causing the second illumination to exit the front major surface into the field of view of the first and second lens assemblies.