Hand held dataform reader having strobing ultraviolet light illumination assembly for reading fluorescent dataforms

• US 6,123,263 A
• Filed: 01/29/1998
• Issued: 09/26/2000
• Est. Priority Date: 01/29/1998
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Meta Holdings Corporation
• Inventors: Feng, Chen
• Primary Examiner(s): Frech, Karl D.
• Assistant Examiner(s): Lee, Diane I.
• Application Number:
  US09/015,363
• Time in Patent Office: 971 Days
• Field of Search: 235/462.41, 235/462.42, 235/462.43, 235/462.48, 235/462.44, 235/472.01, 235/462.04
• US Class Current: 235/462.42
• 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 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks

Abstract

A portable data collection device having a modular imaging-based dataform reader. The dataform reader includes a two dimensional imaging assembly adapted to image and decode a dataform printed using ink that fluoresces when illuminated by ultraviolet light. The imaging assembly includes a two dimensional photosensor array and is actuatable to generate a signal representative of reflected illumination from a target area of the imaging assembly and further includes an illumination assembly having a strobing ultraviolet light source. The illumination assembly includes a pair of flash tube strobe lights which have their output illumination filtered through respective ultraviolet filter thereby permitting only illumination in the ultraviolet range to exit the dataform reader and illuminate the imaging target area. The high intensity, strobing light of the ultraviolet light source permits a reduced exposure period. A targeting illumination assembly is also provided to aid in aiming the device at a target dataform. The targeting illumination assembly and illumination assembly are alternately energized to reduce reflected glare. Fluorescence from the dataform is focused by an optic assembly onto the photosensor array forming an image of the dataform. Image processing circuitry is provided for processing and decoding the image of the dataform.

Claims

1. A dataform reader for a portable data collection device, the dataform reader adapted to image and decode a dataform, the dataform reader comprising:

a) an illumination assembly including an illumination source energizable to direct strobing illumination of a first range of wavelengths toward an imaging target area of the dataform reader for illuminating a target dataform positoned within the imaging target area such that the illuminated dataform emits an illumination pattern corresponding to an image of the target dataform, the illumination pattern having a second range of wavelengths and wherein the first and the second ranges of wavelengths are mutually exclusive;

b) a two dimensional imaging assembly including a two dimensional photosensor array, the two dimensional imaging assembly actuatable to generate a signal representative of the image of the target dataform positioned in the imaging target area;

c) the two dimensional imaging assembly including signal and image processing circuitry for processing and decoding the signal representative of the image of the target dataform positioned in the imaging target area;

d) an optic assembly positioned with respect to the imaging target area to focus the emitted illumination from the target dataform onto the photosensor array and including a filter permitting illumination in the second range of wavelengths to be focused onto the photosensor array and preventing illumination in the first range of wavelengths from being focused onto the photosensor array; and

e) control and selection circuitry electrically coupled to the imaging assembly and the illumination assembly to selectively actuate the imaging assembly and selectively energize the illumination source to image and decode the target dataform.

2. The dataform reader of claim 1 wherein the illumination source comprises a flash tube emitting strobing illumination when energized.

3. The dataform reader of claim 2 wherein the flash tube emits strobing illumination including illumination in the first and second range of wavelengths and the illumination source further includes a filter overlying the flash tube to permit illumination in the first range of wavelengths to be directed toward the imaging target area and preventing illumination in the second range of wavelengths from being directed toward the imaging target area.

4. The dataform reader of claim 1 wherein the first range of wavelengths corresponds to wavelengths in an ultraviolet range of an electromagnetic spectrum.

5. The dataform reader of claim 3 wherein the flash tube emits strobing illumination at a rate of between three and seven flashes per second.

6. The dataform reader of claim 1 wherein the first range of wavelengths has a spectral output centered about a wavelength of substantially 370 nanometers.

7. The dataform reader of claim 1 wherein the second range of wavelengths corresponds to wavelengths in a visible light range of an electromagnetic spectrum.

8. The dataform reader of claim 1 wherein the second range of wavelengths has a spectral output substantially centered about a range of wavelengths between 580 and 605 nanometers.

9. The dataform reader of claim 1 wherein the illumination assembly further includes a targeting illumination assembly electrically coupled to the control and selection circuitry, the control and selection circuitry periodically energizing and deenergizing the targeting illumination assembly to provide targeting illumination to aid in aiming the device at a dataform.

10. The dataform reader of claim 9 wherein the targeting illumination assembly is deenergized when the illumination source is energized.

11. A portable data collection device comprising:

a) a housing defining an interior region; and

b) a dataform reader assembly at least partially supported within the housing interior region, the dataform reader assembly adapted to image and decode a target dataform disposed within a target area of the dataform reader assembly, the target dataform being illuminated by strobing illumination having a first range of wavelengths thereby emitting an illumination pattern corresponding to an image of the dataform to be imaged and decoded, the emitted illumination pattern having a second range of wavelengths, the first and second ranges of wavelengths being mutually exclusive, the dataform reader assembly including;

1) a two dimensional imaging assembly including a two dimensional photosensor array, the two dimensional imaging assembly actuatable to generate a signal representative of an image of the dataform reader target area, the target area image including the image of the target dataform resulting from the illumination pattern emitted by the target dataform;

2) the two dimensional imaging assembly including signal and image processing circuitry for processing and decoding portions of the signal representative of the image of the target dataform;

3) an optic assembly positioned with respect to the dataform reader target area to focus the target area image onto the photosensor array and including a filter permitting illumination in the second range of wavelengths to be focused onto the photosensor array and preventing illumination in the first range of wavelengths from being focused onto the photosensor array;

4) an illumination assembly including a illumination source energizable to generate strobing illumination in the first range of wavelengths and being positioned to illuminate the target area with strobing illumination in the first range of wavelengths when actuated for illuminating the target dataform positioned within the imaging target area such that the illuminated dataform emits the illumination patter corresponding to the image of the target dataform; and

5) control and selection circuitry electrically coupled to the imaging assembly and the illumination assembly to selectively actuate the imaging assembly and selectively energize the illumination source to image and decode the target dataform.

12. The portable data collection device of claim 11 wherein the first range of wavelengths corresponds to wavelengths in an ultraviolet range of an electromagnetic spectrum.

13. The portable data collection device of claim 12 wherein the first range of wavelengths has a spectral output centered about a wavelength of substantially 370 nanometers.

14. The portable data collection device of claim 11 wherein the illumination source comprises a flash tube emitting strobing illumination when energized.

15. The portable data collection device of claim 14 wherein the illumination source emits strobing illumination including illumination in the first and second range of wavelengths and the illumination source further includes a filter to permit illumination in the first range of wavelengths to be directed toward the target area and preventing illumination in the second range of wavelengths from being directed toward the target area.

16. The portable data collection device of claim 14 wherein the flash tube emits strobing illumination at a rate of between three to seven flashes per second.

17. The portable data collection device of claim 11 wherein the second range of wavelengths has a spectral output substantially centered about a range of wavelengths between 580 and 605 nanometers.

18. The portable data collection device of claim 11 wherein the two dimensional photosensor array, the optic assembly and the illumination assembly are supported by a modular housing defining the interior region, the photosensor array being supported within the interior region.

19. The Portable data collection device of claim 11 wherein the illumination assembly further includes a targeting illumination assembly electrically coupled to the control and selection circuitry, the control and selection circuitry periodically energizing and deenergizing the targeting illumination assembly to provide targeting illumination to aid in aiming the device at a dataform.

20. The portable data collection device of claim 19 wherein the targeting illumination assembly is deenergized when the illumination source is energized.