Relief object image generator

• US 6,856,383 B1
• Filed: 09/05/1997
• Issued: 02/15/2005
• Est. Priority Date: 09/05/1997
• Status: Expired due to Fees

• Current Assignee: XL Vision, Inc.
• Original Assignee: Security First Corp
• Inventors: Smith, Ronald S., Vachris, Paul F.
• Primary Examiner(s): Rosenberger, Richard A.
• Application Number:
  US08/926,277
• Time in Patent Office: 2,720 Days
• Field of Search: 356/71, 382124-127, 345/175
• US Class Current: 356/71
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces

Abstract

A device for imaging a relief object without illuminating a platen is disclosed. The device includes a single electrode electroluminescent device, which may be inorganic or organic, and a current source. The current source is coupled to the single electrode of the electroluminescent device and to the relief object to be imaged. The valleys and ridges of the relief object couple current to the electroluminescent device at different magnitudes which causes the electroluminescent device to generate light at different intensities that correspond to the ridges and valleys of the relief object. The generated light forms an image of the relief object which may be focused by optical elements onto a sensor array for capture and image processing. In another embodiment of the invention, a one-to-one sensor array is located proximate the electroluminescent device to capture the image. In an embodiment of the invention which insulates the relief object from current, the electroluminescent device is covered with a variable resistance layer and the variable resistance layer is covered with a flexible electrode. One lead from the current source is coupled to the flexible electrode and another lead is coupled to the single electrode. When a relief object is brought in contact with the flexible electrode, a localized pressures generated by the ridges of the relief object form conductive paths through the variable resistance layer which are lower in electrical resistance than those formed by pressure in the areas adjacent the valleys of the relief object. The different magnitudes of current delivered through the conductive paths to the electroluminescent device cause the electroluminescent device to generate an image of the relief object without exposing the relief object to electrical current.

Claims

1. A system for generating an image of relief object comprising:

an electroluminescent device coupled to an electrode;

a variable resistive layer adjacent to one surface of said electroluminescent device, said variable resistive layer being comprised of conductive particles dispersed through a non-conductive medium, wherein said conducting particles are smaller than the resolution element desired for image;

a flexible electrode substantially covering a surface of said variable resistive layer;

an electrical current source, said electrical current source having one lead coupled to said electrode of said electroluminescent device and a second lead for coupling to said flexible electrode so that current coupled from said current

source to said flexible electrode is strongly coupled through a low resistance path through said variable resistive layer to said electroluminescent device by ridges of said relief object and weakly coupled through a high resistance path through said variable resistive layer to said electroluminescent device by valleys of said relief object whereby more intense light is generated by areas of said electroluminescent device strongly coupled to said current from said ridges of said relief object and less intense light is generated by areas of said electroluminescent device weakly coupled to said current from valleys of said relief object to form an image of the relief object; and

wherein said image is a detailed image of a finger print that could be used for identification.

2. The system of claim 1, wherein said electroluminescent device is an organic electroluminescent device.

3. The device of claim 2, said organic electroluminescent device further comprising:

a thin, sublimed molecular film; and

 

said electrode being a transport anode on which said thin, sublimed molecular film is deposited and to which said one lead of said electrical current source is coupled.

4. The device of claim 3, said thin, sublimed molecular film being tris(8-quinolinolato) aluminum (III).

5. The device of claim 2, said organic electroluminescent device further comprising:

a light emitting polymer; and

said electrode being a transparent anode on which said light emitting polymer is deposited and to which said one lead of said electrical current source is coupled.

6. The device of claim 5, said tight emitting polymer being of the group of poly(p-phenylene vinylene), soluble polythiophene derivatives, or polyanilene.

7. The devices of claim 5, said transparent anode being comprised of a transparent base substrate coated with indium tin oxide.

8. The device of claim 5, said current source being a direct current source having one lead coupled to said transparent anode of said organic device and a second lead exposed at a surface of said flexible electrode so that a localized pressure gradient generated by a portion of a relief object contacting said flexible electrode forms a conductive path through said variable resistive layer which corresponds to said localized pressure gradient whereby said current flows from said direct current source and flexible electrode through said variable resistive layer to said transparent anode of said organic electroluminescent device in correspondence with said localized pressure gradient to generate a light image of said relief object.

9. The system of claim 1, wherein said electroluminescent device is an inorganic electroluminescent device.

10. The system of claim 9 said inorganic electroluminescent device further comprising:

a transparent electrode layer;

a dielectric layer;

a light emitting layer containing light emitting particles, said light emitting layer being interposed between said transparent electrode and said dielectric layer so that a first surface of said transparent electrode and a first surface of said dielectric layer are proximate said light emitting layer; and

 

said current supply source is an alternating current source.

11. The system of claim 1, further comprising:

a sensor array; and

 

optical elements interposed between said sensor array and said electroluminescent device, said optical elements for focusing said generated light on said sensor array.

12. The system of claim 11, wherein said sensor array is an integrated circuit.

13. The system of claim 1, further comprising:

a one-to-one sensor array located proximate said electroluminescent device so that said generated light is sensed by said one-to-one sensor array.

14. The system of claim 13, wherein said one-to-one sensor array is amorphous silicon on glass.

15. The system of claim 1, wherein said conducting particles vary in size from 50 to 100 micrometers.

16. The system of claim 1 wherein a thickness of said variable resistive layer can be from 50 to 100 micrometers.

17. A device for generating an image of a relief object comprising:

a flexible electrode;

a dielectric layer;

a variable resistive layer between said flexible electrode and said dielectric layer, said variable resistive layer being comprised of conductive particles dispersed through a non-conductive medium wherein said conducting particles are smaller than the resolution element desired for image;

a second electrode;

a light emitting layer being interposed between said dielectric layer and said second electrode, said light emitting layer containing light emitting particles; and

an electrical current source having first and second leads, said first lead of said electrical current source being coupled to said second electrode and said second lead of said electrical current source being coupled to said flexible electrode so that a localized pressure gradient generated by a portion of a relief object contacting said flexible electrode forms a conductive path through said variable resistive layer which corresponds to said localized pressure gradient whereby said current flows from said flexible electrode through said variable resistive layer, dielectric layer and light emitting particles to said second electrode in correspondence with said localized pressure gradient to generate a light image of said relief object; and

wherein said image is a detailed image of a finger print that could be used for identification.

18. The device of claim 17, wherein said conducting particles vary in size from 50 to 100 micrometers.

19. The device of claim 17 wherein a thickness of said variable resistive layer can be from 50 to 100 micrometer.

20. A device for generating an image of a relief object comprising:

a flexible electrode;

a dielectric layer and a light emitting layer in which light emitting particles are dispersed;

a variable resistive layer between said flexible electrode and said dielectric layer, said variable resistive layer being comprised of conductive particles dispersed through a non-conductive medium wherein said conducting particles are smaller than the resolution element desired for image;

a second electrode; and

an electrical current source having first and second leads, said first lead of said electrical current source being coupled to said second electrode and said second lead of said electrical current source being coupled to said flexible electrode so that a localized pressure gradient generated by portion of a relief object contacting said flexible electrode forms a conductive path through said variable resistive layer which corresponds to said localized pressure gradient whereby said current flows from said flexible electrode through said variable resistive layer, dielectric layer and light emitting particles to said electrode in correspondence with said localized pressure gradient to generate a light image of said relief object and wherein the relief object has valleys and ridges similar in size and structure to a finger and said image is a detailed image of the relief object that could be used for identification.

21. The device of claim 20, wherein said conducting particles vary in size from 50 to 100 micrometers.

22. The device of claim 20, wherein said relief object is a finger.

23. The device of claim 20, wherein a thickness of said variable resistance layer can be from 50 to 100 micrometers.

24. A system for generating an image of a relief object comprising:

an electroluminescent device having an electrode and configured as an organic electroluminescent device;

a variable resistive layer being proximate to said electroluminescent device, said variable resistive layer being comprised of conductive particles dispersed through a non-conductive medium wherein said conductive particles are smaller than the resolution element desired for image;

a flexible electrode that substantially covers a surface of said variable resistive layer; and

said electrical current source being a direct current source having one lead coupled to said electrode of said organic device and a second lead exposed at a surface of said flexible electrode so that a localized pressure gradient generated by a portion of a relief object contacting said flexible electrode forms a conductive path through said variable resistive layer which corresponds to said localized pressure gradient whereby said current flows from said direct current source and flexible electrode through which said variable resistive layer to said electrode of said organic electroluminescent device in correspondence with said localized pressure gradient to generate a light image of said relief object and wherein the relief object has valleys and ridges similar in size and structure to a finger and said image is a detailed image of the relief object that could be used for identification.

25. The system of claim 24, wherein said relief object is a finger.

26. The system of claim 24, wherein said conductive particles vary in size from 50 to 100 micrometers.

27. The system of claim 24, wherein a thickness of said variable resistance layer can be from 50 to 100 micrometers.

28. A method for imaging a relief object comprising the steps of:

coupling an electrode of an electroluminescent device to a current source;

locating a variable resistive layer adjacent a dielectric layer of said electroluminescent device wherein thickness of said variable resistive layer is smaller than the resolution element desired for image;

substantially covering said variable resistive layer with a flexible electrode;

coupling said current source to said flexible electrode so that said contacting step contacts a relief object contacts said flexible electrode so that pressure from ridges and valleys of said relief object generate relatively low and high resistance conductive paths through said variable resistive layer whereby said current from said current source is provided through said variable resistive layer at different magnitudes corresponding to said ridges and valleys of said relief object and said different currents cause said electroluminescent device to generate said image of said relief object;

generating a detailed image of the relief object that has ridges and valleys similar to a finger; and

using said detailed image for identification.

29. The method of claim 28, wherein said relief object is a finger.

30. The method of claim 28, wherein a thickness of said variable resistive layer can be from 50 to 100 micrometers.

31. The method of claim 28, wherein said conducting particles vary in size from 50 to 100 micrometers.