Uniform ultraviolet strobe illuminator and method of using same

• US 6,032,860 A
• Filed: 08/05/1997
• Issued: 03/07/2000
• Est. Priority Date: 08/05/1997
• Status: Expired due to Term

• Current Assignee: Microscan Systems Inc (Omron Corporation)
• Original Assignee: Cimatrix
• Inventors: Brian, Steven R.
• Primary Examiner(s): Hajec, Donald
• Assistant Examiner(s): RODRIGUEZ, DOUGLAS X
• Application Number:
  US08/906,679
• Time in Patent Office: 945 Days
• Field of Search: 235/454, 235/468, 235/462.31, 235/462.41, 235/462.43, 235/462.44, 235/491
• US Class Current: 235/454
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks

Abstract

An apparatus and method for illuminating with ultraviolet light an optically readable code formed with ultraviolet material, preferably an ultraviolet ink or resin. The apparatus includes:

a housing having an interior chamber, an interior wall on one side of the interior chamber, a first side of the chamber facing the ultraviolet material, a second side of the chamber opposite the first side, a first opening and a second opening in the first side, and a third opening in the second side,

a passageway having a perimeter surrounded by an outer wall, the passageway extending substantially from the second opening to the third opening, the passageway perimeter defining the interior wall of the chamber,

a strobe lamp disposed within the chamber having an ultraviolet light output wherein the passageway perimeter prevents the ultraviolet light generated by the strobe lamp from passing into the passageway, and

an ultraviolet bandpass filter covering the first opening of the chamber, but not the passageway, to block substantially all nonultraviolet light generated by the strobe lamp. The apparatus preferably further includes a second filter of a color which matches the color of the ultraviolet material to transmit only light of that color to an image sensor, such as a CCD device, positioned behind the passageway. The method includes illuminating the strobe lamp in response to the activation of a proximity sensor and then reading the code with the image sensor.

Claims

1. An apparatus for illuminating an ultraviolet material with ultraviolet light comprising:

a housing having an interior chamber, an interior wall on one side of the interior chamber, a first side of the chamber facing the ultraviolet material, a second side of the chamber opposite the first side, a first opening and a second opening in the first side, and a third opening in the second side,

a passageway having a perimeter surrounded by an outer wall, the passageway extending substantially from the second opening to the third opening, the passageway perimeter defining the interior wall of said chamber,

a strobe lamp disposed within said chamber having an ultraviolet light output wherein the passageway perimeter prevents the ultraviolet light generated by said strobe lamp from passing into said passageway, and

an ultraviolet bandpass filter covering said first opening of said chamber, but not said passageway, to block substantially all nonultraviolet light generated by said strobe lamp.

2. The apparatus of claim 1 wherein said ultraviolet material is a first color and said apparatus further comprises a second filter of said first color covering said second opening.

3. The apparatus of claim 2 wherein the ultraviolet material is on a substrate and further comprising a proximity sensor having an output corresponding to said substrate moving into proximity of said proximity sensor and means for causing said strobe lamp to flash in response to said sensor output.

4. The apparatus of claim 3 wherein the causing means operates to cause the strobe lamp to flash once in response to a sensor output.

5. The apparatus of claim 2 wherein said ultraviolet material is blue and said second filter further comprises a bandpass filter passing light between the wavelengths of 350-550 nm.

6. The apparatus of claim 5 wherein said strobe lamp is ring-shaped and surrounds said passageway.

7. The apparatus of claim 6 wherein said passageway is cylindrical.

8. The apparatus of claim 1 wherein said ultraviolet material comprises an ink or resin formed as an optically readable code.

9. The apparatus of claim 1 further comprising a stand on which an image sensing means is rested opposite said third opening.

10. The apparatus of claim 9 wherein said image sensing means is a camera.

11. The apparatus of claim 9 wherein said image sensing means is a CCD device.

12. The apparatus of claim 1 wherein said ultraviolet bandpass filter transmits light in the range of 230-430 nm.

13. A method of reading an optically readable code imprinted on a surface in ultraviolet material comprising a first color, said method comprising:

providing an illuminator apparatus comprising;

a strobe lamp;

a housing having a light emitting end and a cavity;

a passageway disposed in said housing optically isolated from said strobe lamp;

said strobe lamp having an ultraviolet light output, and an ultraviolet bandpass filter positioned to block substantially all nonultraviolet light generated by said strobe lamp from impinging upon said optically readable code;

placing a sensor near said illuminator apparatus and means for reading an image behind said illuminator apparatus;

moving an optically readable code first in frontof said sensor to activate said sensor and then moving said code in front of said illuminator apparatus;

illuminating the strobe lamp in response to the activation of said sensor, said ultraviolet filter permitting only ultraviolet light to pass through onto said optically readable code, thereby causing said ultraviolet material of said optically readable code to fluoresce and emit light substantially of said first color comprising a first band of wavelengths; and

reading said optically readable code with said reading means.

14. The method of claim 13 wherein providing said illuminator apparatus further comprises

providing a housing having an interior chamber, an interior wall on one side of the interior chamber, a first side of said chamber facing said ultraviolet material, a second side of said chamber opposite said first side, a first opening and a second opening in said first side, and a third opening in said second side, a passageway having a perimeter surrounded by an outer wall, the passageway extending substantially from the second opening to the third opening, the passageway perimeter defining the interior wall of said chamber and preventing the ultraviolet light generated by said strobe lamp from passing into said passageway, and covering said second opening with a second bandpass filter of said first color, and said method further comprises using said second filter to filter out ambient light and permit only light of said first color to enter said passageway.

15. The method of claim 14 wherein placing the reading means further comprises providing a camera and placing said camera behind said third opening.

16. The method of claim 14 wherein placing the reading means further comprises providing a CCD device and placing said CCD device behind said third opening.

17. Apparatus for illuminating an ultraviolet optically readable symbol comprising:

a housing having a light emitting end and a cavity;

a strobe light disposed in said housing cavity having an ultraviolet radiation output;

a passageway disposed in said housing optically isolated from said strobe light; and

a first bandpass filter coupled to said housing so that the strobe light ultraviolet radiation output passes through said first filter and does not pass into said passageway, the first filter having a bandpass frequency range in the ultraviolet range.

18. The apparatus of claim 17 wherein said ultraviolet material is a first color and said apparatus further comprises a second filter of said first color covering said second opening.

19. The apparatus of claim 18 wherein the ultraviolet material is on a substrate and further comprising a proximity sensor having an output corresponding to said substrate moving into proximity of said proximity sensor and means for causing said strobe lamp to flash in response to said sensor output.

20. The apparatus of claim 19 wherein the causing means operates to cause the strobe lamp to flash once in response to a sensor output.

21. The apparatus of claim 18 wherein said ultraviolet material is blue and said second filter further comprises a bandpass filter passing light between the wavelengths of 350-550 nm.

22. The apparatus of claim 21 wherein said strobe lamp is ring-shaped and surrounds said passageway.

23. The apparatus of claim 22 wherein said passageway is cylindrical.

24. The apparatus of claim 17 wherein said ultraviolet material comprises an ink or resin formed as an optically readable code.

25. The apparatus of claim 17 further comprising a stand on which an image sensing means is rested opposite said third opening.

26. The apparatus of claim 25 wherein said image sensing means is a camera.

27. The apparatus of claim 25 wherein said image sensing means is a CCD device.

28. The apparatus of claim 17 wherein said first bandpass filter transmits light in the 230-430 nm range.