INDICIA READING TERMINAL INCLUDING OPTICAL FILTER

• US 20140312121A1
• Filed: 01/28/2014
• Published: 10/23/2014
• Est. Priority Date: 01/21/2010
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Lu, Reck, Zhu, Xiaoxun
• Granted Patent: US 9,292,723 B2
• Time in Patent Office: Days
• US Class Current: 235/468
• CPC Class Codes: G06K 19/0614 the marking being selective to wavelength, e.g. color barcode or barcodes only visible under UV or IR methods or arrangements for sensing record carriers using a selected wavelength, see G06K7/12
• 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 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks

Abstract

Embodiments of the present invention comprise an indicia reading terminal that is operatively configured to decode visible and non-visible decodable indicia. The terminal can comprise an excitation illumination module for illuminating the decodable indicia with light that has a wavelength selected so as to permit the decodable indicia to emit light. The terminal can also comprise a filter module with an optical filter that has filter regions configured to pass certain wavelengths of light. The terminal can also comprise an image sensor module with an image sensor located so as to receive light emitted from the decodable indicia from the filter region.

Claims

1. An indicia reading terminal comprising:

an illumination source for casting light onto an indicia, the cast light having a wavelength in a non-visible spectrum that causes the indicia to emit light in a visible wavelength;

an optical filter comprising a first filter region having a pass-band matching the visible wavelength of the light emitted by the indicia;

an image sensor for generating a signal corresponding to light incident on the image sensor, the image sensor having an optical axis on which the optical filter is aligned;

wherein the terminal is configured for assigning the optical filter'"'"'s pass-band and/or the wavelength of the light cast by the illumination source.

2. The terminal of claim 1, comprising an actuator coupled to the optical filter for changing the wavelength of light that passes through the filter along the optical axis.

3. The terminal of claim 1, wherein the optical filter comprises a plurality of filter regions each having a pass-band for a different wavelength.

4. The terminal of claim 1, comprising an actuator coupled to the optical filter, wherein:

the optical filter comprises a plurality of filter regions each having a pass-band for a different wavelength;

the actuator moves the optical filter to place one of the filter regions into alignment with the optical axis; and

the filter region aligned with the optical axis is selected based on the wavelength of the light cast by the illumination source.

5. The terminal of claim 1, wherein the illumination source is configured for casting light at a plurality of wavelengths.

6. The terminal of claim 1, comprising an imaging lens for focusing light onto the image sensor.

7. The terminal of claim 1, comprising an imaging lens assembly optically coupled to the image sensor, wherein:

the optical filter comprises an optical coating on the imaging lens assembly;

the optical coating passes light in the visible wavelength emitted by the indicia.

8. The terminal of claim 1, wherein the optical filter blocks all wavelengths outside of the pass-band.

9. The terminal of claim 1, wherein:

the image sensor comprises a plurality of pixels; and

the optical filter comprises an optical coating on a pixel, the optical coating forming a filter region that passes light having a visible wavelength.

10. The terminal of claim 1, wherein;

the image sensor comprises a plurality of pixels; and

the optical filter comprises an optical coating on a plurality of pixels, wherein the optical coating forms a plurality of filter regions each having a pass-band for a different wavelength.

11. The terminal of claim 1, wherein the illumination source comprises:

a light emitting diode for generating a first light beam having a first wavelength for illuminating the indicia; and

a laser diode for generating a second light beam of laser light.

12. The terminal of claim 1, wherein the image sensor comprises a pixel array, the pixel array comprising color pixels and monochrome pixels, the color pixels being located at spaced apart positions on the pixel array among the monochrome pixels.

13. The terminal of claim 1, wherein the optical filter comprises a substrate having separate pass-bands for wavelengths corresponding to red light, green light, and orange light.

14. An indicia reading terminal comprising:

an illumination source for casting light onto an indicia, the cast light having a wavelength in a non-visible spectrum that causes the indicia to emit light in a visible wavelength;

an optical filter comprising a plurality of filter regions each having a pass-band for a different wavelength spectrum of visible light;

an image sensor for generating a signal corresponding to light incident on the image sensor, the image sensor having an optical axis on which the optical filter is aligned, the image sensor comprising a pixel array, the pixel array comprising color pixels and monochrome pixels, the color pixels being located at spaced apart positions on the pixel array among the monochrome pixels;

wherein the terminal is configured for assigning the optical filter'"'"'s pass-band and/or the wavelength of the light cast by the illumination source.

15. The terminal of claim 14, comprising an actuator coupled to the optical filter, wherein the actuator moves the optical filter to place one of the filter regions into alignment with the optical axis.

16. The terminal of claim 14, wherein the illumination source is configured for casting light at a plurality of wavelengths.

17. The terminal of claim 14, comprising an imaging lens for focusing light onto the image sensor.

18. The terminal of claim 14, comprising an imaging lens assembly optically coupled to the image sensor, wherein the optical filter comprises an optical coating on the imaging lens assembly;

19. The terminal of claim 14, wherein the optical filter comprises an optical coating on a portion of the pixel array, the optical coating forming a filter region that passes light having a visible wavelength.

20. The terminal of claim 14, wherein:

the image sensor comprises a plurality of pixels; and

the optical filter comprises an optical coating on a pixel, the optical coating forming a filter region that passes light having a visible wavelength.

21. The terminal of claim 14, wherein the illumination source comprises:

a light emitting diode for generating a first light beam having a first wavelength for illuminating the indicia; and

a laser diode for generating a second light beam of laser light.

22. The terminal of claim 14, wherein the optical filter comprises a substrate having separate pass-bands for wavelengths corresponding to red light, green light, and orange light.

23. A method comprising:

aligning an optical axis of an image sensor with an indicia that emits light in a visible wavelength in response to light in a non-visible wavelength spectrum;

illuminating the indicia with light having a wavelength in a non-visible wavelength spectrum; and

setting (i) the wavelength of the light illuminating the indicia to correspond to the non-visible wavelength spectrum in response to which the indicia emits light in the visible wavelength and/or (ii) a pass-band of an optical filter aligned with the image sensor'"'"'s optical axis to correspond to the visible wavelength in which the indicia emits light.

24. The method of claim 23, comprising aligning a filter region of the optical filter with the image sensor'"'"'s optical axis.

25. The method of claim 23, wherein the optical filter comprises a plurality of filter regions each having a pass-band for a different wavelength, the method comprising:

selecting a filter region based on the wavelength of the light illuminating the indicia; and

aligning the selected filter region with the image sensor'"'"'s optical axis.

26. The method of claim 23, comprising receiving a first trigger signal, wherein the steps of illuminating and setting are performed in response to the first trigger signal.

27. The method of claim 23, wherein the image sensor generates a signal corresponding light incident on the image sensor, the method comprising:

receiving a first trigger signal;

wherein the steps of illuminating and setting are performed in response to the first trigger signal;

in response to the first trigger signal, attempting to decode the indicia based on the signal generated by the image sensor; and

in response to a failed attempt to decode the indicia, setting (i) the wavelength of the light illuminating the indicia to a different wavelength than the previously set wavelength of light illuminating the indicia and/or (ii) a pass-band of an optical filter aligned with the image sensor'"'"'s optical axis to correspond to a different wavelength than the previously set wavelength of the pass-band.