Fingerprint sensors

• US 9,536,129 B2
• Filed: 01/21/2016
• Issued: 01/03/2017
• Est. Priority Date: 05/17/2011
• Status: Active Grant

• Current Assignee: HID Global Corporation (Assa Abloy AB)
• Original Assignee: Cross Match Technologies Incorporated (Assa Abloy AB)
• Inventors: Carver, John F., Raguin, Daniel H.
• Primary Examiner(s): Werner, Brian P
• Application Number:
  US15/003,500
• Publication Number:
  US 20160140380A1
• Time in Patent Office: 348 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: G06V 40/1324 by using geometrical optics, e.g. using prisms G06V40/1312 takes precedence
• CPC Class Codes: G06V 40/1394 using acquisition arrangements

Abstract

A sensor for detecting fingerprints is provided having first and second substrates, a two-dimensional array of sensing elements formed on the first substrate, and a plurality of thin-film transistors or TFTs for controlling the sensing elements at pixel locations along the array. Each of the sensing elements detects one of electrical signals (e.g., capacitance, resistance, or impedance), temperature, or light via one of the first or second substrates representative of one or more fingerprints. The top of the second substrate or the bottom of the first substrate may provide a platen upon which one or more fingers can be disposed. The sensor may be utilized in a fingerprint scanner having one or more processors driving sensing elements or reading from sensing elements analog signals representative of one or more fingerprints, and generating an image representative of the one or more fingerprints from the analog signals.

Claims

1. A sensor for detecting one or more fingerprints comprising:

a first substrate and a second substrate;

a two-dimensional array of sensing elements between said first substrate and said second substrate, wherein said sensing elements of said array are at least light sensing elements;

a plurality of thin-film transistors for controlling said sensing elements; and

a plurality of light sources which actively generates light being disposed between said first substrate and said second substrate distributed at locations among said array of said light sensing elements for transmitting illumination via said second substrate, in which said light sensing elements detect reflected illumination representative of one or more fingerprints via said second substrate, wherein each of said light sources comprises at least one of a diffractive element or a Fresnel element between the light source and said second substrate for shaping light from the light source without any TIR between the light source and said at least one of a diffractive element or a Fresnel element.

2. The sensor according to claim 1 wherein said second substrate has a surface opposite said first substrate, and said surface provides a platen surface for placement upon by said one or more fingers.

3. The sensor according to claim 1 further comprising pixel locations along said array each associated with a different one of said light sensing elements, in which said light sources are distributed every N number said pixel locations.

4. The sensor according to claim 3 wherein N equals one.

5. The sensor according to claim 1 wherein each of said light sources represents one or more light emitters.

6. The sensor according to claim 1 further comprising one or more processors, each of said thin-film transistors controls said one or more of said sensing elements responsive to said one or more processors to enable said one or more processor to one or more of driving said one or more of said sensing elements or reading from said one or more sensing elements analog signals representative of said one or more fingerprints, and generates an image representative of said one or more fingerprints responsive to said analog signals.

7. The sensor according to claim 6 wherein at least one of said one or more of said processors is part of a computer system.

8. The sensor according to claim 1 wherein said light sources are each one or more light emitting diodes.

9. The sensor according to claim 1 wherein said light sources are each one or more organic light emitting diodes.

10. The sensor according to claim 1 wherein said second substrate has a surface opposite said first substrate, and said surface provides a platen surface for placement upon by said one or more fingers, each of said light sources represents one or more light emitters, wherein said at least one of a diffractive element or a Fresnel element represent optics that one or more of steer and collimate illumination from said one more light emitters in direction of said platen surface.

11. The sensor according to claim 1 further comprising other sensing elements for receiving temperature signals via one of said first substrate or said second substrate.

12. The sensor according to claim 1 further comprising pixel locations along said array each associated with a different one of said light sensing elements, wherein at at least one of said pixel locations along said array is at least one other sensing element for sensing a different characteristic than light.

13. The sensor according to claim 1 further comprising sensing elements for sensing one or more different types of characteristics than light.

14. The sensor according to claim 1 wherein said illumination is green or of one or more wavelengths shorter than green.

15. The sensor according to claim 1 wherein said light sensing elements are along a plane, and said light sources are along a same plane as said light sensing elements.

16. The sensor according to claim 1 wherein said light sensing elements are along a plane, and said light sources are along a different plane from said light sensing elements.

18. The sensor according to claim 1 wherein said array of light sensing elements further comprises electrical sensing elements for receiving electrical signals representative of one or more fingerprints or for detecting liveliness of said one or more fingers.

19. The sensor according to claim 18 wherein said electrical signals are one of capacitance, resistance, or impedance.

17. A method for detecting one or more fingerprints comprising:

providing a two-dimensional array of sensing elements between a first substrate and;

controlling said sensing elements using a plurality of thin-film transistors;

providing light sources for actively generating light between said first substrate and said second substrate for transmitting illumination via said second substrate, and said light sensing elements detect reflected illumination representative of one or more fingerprints presented upon said second substrate; and

providing for each of said light sources at least one of a diffractive element or a Fresnel element between the light source and said second substrate for shaping light from the light source without any TIR between the light source and said at least one of a diffractive element or a Fresnel element.

20. A device for capturing an image of an object comprising:

a first substrate and a second substrate;

a two dimensional array of light sensing elements, in which one of said first and second substrates provides a platen surface for capturing an image of an object when disposed upon said platen surface;

a plurality of thin-film transistors for controlling said light sensing elements; and

a plurality of light sources which actively generates light being disposed between said first and second substrates to enable reflected light representing said object to be captured onto said two dimensional array of light sensing elements, optics between said light sources and said platen surface comprising at least one of a diffractive element, or a Fresnel element, and without any TIR between the light source and said at least one of a diffractive element or a Fresnel element.

21. The device according to claim 20 wherein said object is a document, a signature, a bar code, or one or more fingers.

22. The device according to claim 20 wherein said optics shape illumination from said light sources to said platen surface.

23. The device according to claim 20 wherein said optics steer illumination from said light sources to said platen surface.

24. The device according to claim 20 wherein said optics collimate illumination from said light sources to said platen surface.