Biometric sensor

• US 20040252867A1
• Filed: 02/19/2002
• Published: 12/16/2004
• Est. Priority Date: 01/05/2000
• Status: Abandoned Application

• Current Assignee: Je-Hsiung Lan, John Van Zandt
• Original Assignee: Je-Hsiung Lan, John Van Zandt
• Inventors: Van Zandt, John, Lan, Je-Hsiung
• Application Number:
  US10/079,960
• Publication Number:
  US 20040252867A1
• Time in Patent Office: Days
• US Class Current: 382/124
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: H10K 59/40 OLEDs integrated with touch screens

Abstract

A system and methods for sensing and imaging a fingerprint surface using an optical sensing device. The fingerprint system utilizes an optical detector to capture light selectively reflected by the relief features of the fingerprint surface. A number of different methods for lighting and positioning the sensor are described to desirably enhance the contrast and clarity of the rendered image and to improve accuracy in discriminating between fingerprints. A color filter system is also described that is integrated into fingerprint sensor and improves the quality of the resultant fingerprint image.

Claims

1. A fingerprint sensor wherein a finger placed on the sensor is illuminated by both a light source and by ambient light, the fingerprint sensor having a color filter that filters out a portion of the ambient light, the fingerprint sensor comprising:

a contact surface which receives a fingertip of a user;

at least one light source which generates at least green light that is reflected by the fingertip;

a color filter which is substantially transparent to the green light and substantially opaque to a portion of ambient light that is substantially transmitted through the fingertip; and

a plurality of optical detectors disposed from the contact surface with at least a portion of the color filter disposed between the optical detectors and the contact surface, the optical detectors positioned to receive the green light reflected by the fingertip, the optical detectors generating electrical signals in response to the received light, thereby providing an electronic representation of a fingerprint corresponding to the fingertip.

2. The fingerprint sensor of claim 1, wherein the portion of ambient light that is substantially transmitted through the fingertip is primarily red light.

3. The fingerprint sensor of claim 1, wherein the light source comprises a green light-emitting diode.

4. The fingerprint sensor of claim 1, wherein the color filter comprises a polyimide material with dissolved colorants.

5. The fingerprint sensor of claim 1, wherein the color filter comprises an organic material.

6. The fingerprint sensor of claim 1, wherein the color filter comprises an inorganic material.

7. The fingerprint sensor of claim 6, wherein the color filter comprises a multilayer structure of a-SiN_x/a-SiO_x/a-SiN_xO_y.

8. The fingerprint sensor of claim 1, wherein the color filter has a thickness between approximately 1.0 um to approximately 3.0 um.

9. The fingerprint sensor of claim 1, wherein the color filter substantially covers the plurality of optical detectors.

10. The fingerprint sensor of claim 1, wherein the plurality of optical detectors are separated from one another, thereby defining a region between the optical detectors, and the color filter is patterned such that the color filter does not substantially cover the region between the optical detectors.

11. The fingerprint sensor of claim 1, wherein the plurality of optical detectors comprise a planar array of pixels.

12. The fingerprint sensor of claim 11, wherein the planar array of pixels is arranged in generally orthogonal columns and rows.

13. The fingerprint sensor of claim 1, wherein each optical detector comprises a switching diode and a photodiode.

14. The fingerprint sensor of claim 1, wherein the plurality of optical detectors comprises an opaque matrix which substantially bounds each optical detector, thereby separating the optical detectors from one another.

15. The fingerprint sensor of claim 1, further comprising an opaque matrix which substantially bounds portions of the color filter, thereby separating the portions of the color filter from one another.

16. The fingerprint sensor of claim 1, further comprising an opaque matrix which substantially bounds each optical detector with an associated portion of the color filter.

17. The fingerprint sensor of claim 1, wherein the plurality of optical detectors and the light source are substantially co-planar.

18. A fingerprint sensor comprising:

at least one light source which generates light that is reflected by a fingertip;

a color filter which is substantially transparent to green light and substantially opaque to non-green light; and

at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive the green light reflected by the fingertip.

19. A fingerprint sensor comprising:

a contact surface which receives a fingertip of a user, the fingertip comprising a pattern of ridges and valleys, the contact surface in contact with the ridges of the fingertip;

at least one light source which generates light that is reflected from the contact surface;

a color filter which is substantially transparent to green light and substantially opaque to non-green light; and

at least one optical detector disposed from the contact surface with at least a portion of the color filter disposed between the optical detector and the contact surface, the optical detector positioned to receive the green light reflected from the contact surface.

20. A fingerprint sensor comprising:

a substrate which is substantially transparent to green light;

at least one light source coupled to the substrate, the light source generating light that propagates through the substrate and is reflected by a fingertip;

a color filter which is substantially transparent to green light and substantially opaque to non-green light; and

at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive the green light reflected by the fingertip.

21. A fingerprint sensor comprising:

at least one light source which generates light that is reflected by a fingertip;

a color filter which is substantially transparent to green light and substantially opaque to non-green light; and

an optical detector layer disposed from the fingertip with at least a portion of the color filter disposed between the optical detector layer and the fingertip, the optical detector layer positioned to receive the green light reflected by the fingertip.

22. A fingerprint sensor comprising:

at least one light source which generates light that is reflected by a fingertip;

a color filter which is substantially transparent to non-red light and substantially opaque to red light; and

at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive the non-red light reflected by the fingertip.

23. A fingerprint sensor comprising:

a contact surface which receives a fingertip of a user, the fingertip comprising a pattern of ridges and valleys, the contact surface in contact with the ridges of the fingertip;

at least one light source which generates light that is reflected from the contact surface;

a color filter which is substantially transparent to non-red light and substantially opaque to red light; and

at least one optical detector disposed from the contact surface with at least a portion of the color filter disposed between the optical detector and the contact surface, the optical detector positioned to receive the non-red light reflected from the contact surface.

24. A fingerprint sensor comprising:

a substrate which is substantially transparent to non-red light;

at least one light source coupled to the substrate, the light source generating light that propagates through the substrate and is reflected by a fingertip;

a color filter which is substantially transparent to non-red light and substantially opaque to red light; and

at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive the non-red light reflected by the fingertip.

25. A fingerprint sensor comprising:

at least one light source which generates light that is reflected by a fingertip;

a color filter which is substantially transparent to non-red light and substantially opaque to red light; and

an optical detector layer disposed from the fingertip with at least a portion of the color filter disposed between the optical detector layer and the fingertip, the optical detector layer positioned to receive the non-red light reflected by the fingertip.

26. A fingerprint sensor comprising:

at least one light source which generates light that is reflected by a fingertip;

a color filter which is substantially opaque to a portion of ambient light that passes through the fingertip; and

at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive a portion of the light that reflects from the fingertip and passes through the color filter.

27. A fingerprint sensor comprising:

a contact surface which receives a fingertip of a user, the fingertip comprising a pattern of ridges and valleys, the contact surface in contact with the ridges of the fingertip;

at least one light source which generates light that is reflected from the contact surface;

a color filter which is substantially opaque to a portion of ambient light that passes through the fingertip; and

at least one optical detector disposed from the contact surface with at least a portion of the color filter disposed between the optical detector and the contact surface, the optical detector positioned to receive a portion of the light that reflects from the contact surface and passes through the color filter.

28. A fingerprint sensor comprising:

at least one light source coupled to a substrate, the light source generating light that propagates through the substrate and is reflected by a fingertip, the substrate being substantially transparent to the light generated by the light source;

a color filter which is substantially opaque to a portion of ambient light that passes through the fingertip; and

at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive a portion of the light that reflects from the fingertip.

29. A fingerprint sensor comprising:

at least one light source which generates light that is reflected by a fingertip;

a color filter which is substantially opaque to a portion of ambient light that passes through the fingertip; and

an optical detector layer disposed from the fingertip with at least a portion of the color filter disposed between the optical detector layer and the fingertip, the optical detector layer positioned to receive a portion of the light that reflects from the fingertip.

30. A fingerprint sensor comprising:

at least one light source which generates light that is reflected by a fingertip; and

at least one optical detector disposed from the fingertip, the optical detector positioned to receive the light generated by the light source and reflected by the fingertip, the optical detector comprising a color filter which is substantially transparent to the light that is generated by the light source and reflected by the fingertip and substantially opaque to a portion of ambient light substantially transmitted through the fingertip, whereby the optical detector is substantially responsive to the light that is generated by the light source and reflected by the fingertip and is not substantially responsive to the portion of ambient light substantially transmitted through the fingertip.

31. A fingerprint sensor comprising:

at least one light source which generates light that is reflected by a fingertip; and

a plurality of optical detectors disposed from the fingertip, the optical detectors positioned to receive the light generated by the light source and reflected by the fingertip, the optical detectors each comprising;

a switching diode;

a photodiode comprising a photoactive p-layer, an intrinsic layer, and an n-layer; and

a color filter layer covering the photoactive p-layer, the color filter layer substantially transparent to the light generated by the light source and reflected by the fingertip and substantially opaque to a portion of ambient light substantially transmitted through the fingertip,

whereby the optical detectors are substantially responsive to light that is generated by the light source and not substantially responsive to the portion of ambient light substantially transmitted through the fingertip.

32. A fingerprint sensor wherein a finger placed on the sensor is illuminated by both a light source and by ambient light, the fingerprint sensor having a color filter that filters a portion of the ambient light, the fingerprint sensor comprising:

a substrate comprising a first material which is substantially transparent to light with wavelengths within a first range of wavelengths;

a contact surface which receives a fingertip of a user;

a color filter layer comprising a second material which is substantially transparent to light with wavelengths within the first range of wavelengths and substantially opaque to a portion of ambient light with wavelengths within a second range of wavelengths, the portion of ambient light propagating through the fingertip;

at least one light source coupled to the substrate, the light source generating light with at least one wavelength within the first range of wavelengths, the light propagating through the substrate to the fingertip; and

a plurality of optical detectors disposed from the contact surface with at least a portion of the second material disposed between the optical detectors and the contact surface, the optical detectors positioned to receive light generated by the light source and reflected by the fingertip, the optical detectors generating electrical signals in response to the received light, thereby providing an electronic representation of a fingerprint corresponding to the fingertip.

33. A method of sensing a fingerprint comprising a pattern of ridges and valleys of a fingertip of a user, the method comprising:

receiving the fingertip on a fingerprint sensor;

receiving a first light substantially transmitted through the fingertip to a contact surface, whereby the first light is generated by ambient light sources;

generating a second light and substantially transmitting the second light to the fingertip from the contact surface;

reflecting a portion of the second light from the fingertip;

filtering the first light substantially transmitted through the contact surface from the second light reflected from the fingertip; and

detecting the second light reflected from the fingertip, thereby imaging the fingerprint of the fingertip.

34. The method of claim 33, wherein receiving the fingertip on the fingerprint sensor comprises contacting a contact surface of the fingerprint sensor with the ridges of the fingertip.

35. The method of claim 33, wherein reflecting a portion of the second light from the fingertip comprises reflecting from the ridges of the fingertip with a first reflectivity and reflecting from the valleys of the fingertip with a second reflectivity.

36. The method of claim 33, wherein receiving the first light substantially transmitted through the fingertip comprises receiving primarily red light.

37. The method of claim 33, wherein generating the second light is performed using a light source comprising a green light-emitting diode.

38. The method of claim 33, wherein filtering the first light comprises using a color filter comprising a polyimide material with dissolved colorants.

39. The method of claim 33, wherein filtering the first light is filtered comprises using a color filter having a thickness between approximately 1.0 um to approximately 3.0 um.

40. The method of claim 33, wherein detecting the second light comprises using a plurality of optical detectors comprising a planar array of pixels.

41. The method of claim 40, further comprising arranging the planar array of pixels in generally orthogonal columns and rows.

42. The method of claim 33, wherein detecting the second light comprises using a plurality of optical detectors comprising an opaque matrix which substantially bounds each optical detector, thereby separating the optical detectors from one another.

43. The method of claim 33, wherein filtering the first light comprises using an opaque matrix which substantially bounds portions of the color filter, thereby separating the portions of the color filter from one another.

44. The method of claim 33, wherein filtering the first light comprises using an opaque matrix which substantially bounds each optical detector with an associated portion of the color filter.

45. The method of claim 33, wherein detecting the second light comprises using a plurality of optical detectors which is substantially co-planar with a light source which generates the second light.

46. A fingerprint sensor comprising:

at least one light source which generates green light that is reflected by a fingertip;

a color filter which is substantially transparent to the green light generated by the light source and reflected by the fingertip, and which is substantially opaque to non-green light; and

at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive the green light generated by the light source and reflected by the fingertip.

47. The fingerprint sensor of claim 46, wherein the light source comprises a green light-emitting diode.

48. The fingerprint sensor of claim 46, wherein the light source comprises a microlens array.

49. The fingerprint sensor of claim 46, wherein the optical detector comprises an active matrix sensor array.

50. A fingerprint sensor comprising:

at least one light source comprising a green light-emitting diode which generates green light that is reflected by a fingertip;

a color filter which is substantially transparent to the green light generated by the green light-emitting diode and reflected by the fingertip, and which is substantially opaque to non-green light; and

at least one optical detector comprising an active matrix sensor array disposed from the fingertip with at least a portion of the color filter disposed between the active matrix sensor array and the fingertip, the active matrix sensor array positioned to receive the green light generated by the green light-emitting diode and reflected by the fingertip.

51. The fingerprint sensor of claim 50, further comprising a microlens array that reflects the green light onto the fingertip.

52. The fingerprint sensor of claim 51, wherein the microlens array is positioned below the active matrix sensor array.

53. The fingerprint sensor of claim 51, wherein the microlens array comprises a plurality of reflective, curved surfaces.

54. The fingerprint sensor of claim 51, wherein the fingerprint sensor further comprises a light shield positioned to block light from the green light-emitting diode from directly illuminating the fingertip without reflecting from the microlens array.

55. A fingerprint sensor comprising:

at least one light source comprising a microlens array and a green light-emitting diode which generates green light that is reflected by a fingertip;

a color filter which is substantially transparent to the green light generated by the light source and reflected by the fingertip, and which is substantially opaque to non-green light; and

at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive the green light generated by the light source and reflected by the fingertip.

56. A fingerprint sensor comprising:

at least one light source comprising a microlens array and a green light-emitting diode which generates green light that is reflected by a fingertip;

a color filter which is substantially transparent to the green light generated by the light source and reflected by the fingertip, and which is substantially opaque to non-green light; and

at least one optical detector comprising an active matrix sensor array disposed from the fingertip with at least a portion of the color filter disposed between the active matrix sensor array and the fingertip, the active matrix sensor array positioned to receive the green light generated by the green light-emitting diode and reflected by the fingertip.

57. A fingerprint sensor comprising:

at least one light source which generates non-red light that is reflected by a fingertip;

a color filter which is substantially transparent to the non-red light generated by the light source and reflected by the fingertip, and which is substantially opaque to red light; and

at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive the non-red light generated by the light source and reflected by the fingertip.

58. The fingerprint sensor of claim 57, wherein the light source comprises a green light-emitting diode.

59. The fingerprint sensor of claim 57, wherein the light source comprises a microlens array.

60. The fingerprint sensor of claim 57, wherein the optical detector comprises an active matrix sensor array.

61. A fingerprint sensor comprising:

at least one light source which generates light that is reflected by a fingertip, the light having a wavelength which is not substantially transmitted through the fingertip;

a color filter which is substantially opaque to a portion of ambient light that passes through the fingertip, and which is substantially transparent to the light generated by the light source and reflected by the fingertip; and

is at least one optical detector disposed from the fingertip with at least a portion of the color filter disposed between the optical detector and the fingertip, the optical detector positioned to receive the light generated by the light source and reflected by the fingertip.