Fingerprint sensing device

• US 8,605,960 B2
• Filed: 03/02/2009
• Issued: 12/10/2013
• Est. Priority Date: 03/02/2009
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Orsley, Timothy James
• Primary Examiner(s): Chowdhury, Tarifur
• Assistant Examiner(s): HANSEN, JONATHAN M
• Application Number:
  US12/396,285
• Publication Number:
  US 20100220900A1
• Time in Patent Office: 1,744 Days
• Field of Search: 356/124, 382/124, 382/321
• US Class Current: 382/124
• CPC Class Codes: G06F 2203/0338 Fingerprint track pad, i.e. fingerprint sensor used as pointing device tracking the fingertip image
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0488 using a touch-screen or digitiser, e.g. input of commands through traced gestures
• CPC Class Codes: G06V 40/1335 Combining adjacent partial images (e.g. slices) to create a composite input or reference pattern; Tracking a sweeping finger movement

Abstract

A fingerprint sensing module for a touch screen device. The fingerprint sensing module includes a sensor, a light source, a motion detector, and an image processor. The sensor sets to capture portions for a fingerprint image as a finger is slid over the sensor. The motion detector determines a rate of the finger movement as the finger is slide over the touch screen device. The image processor reads fingerprint images from the sensor and the fingerprint motion data from the motion detector. The image processor subsequently combines portions of the fingerprint images into a complete fingerprint in accordance with the rate of the finger'"'"'s movement.

Claims

1. A fingerprint sensing module for a touch screen device, comprising:

a substrate;

a sensor having at least one linear sensor array attached to the substrate, the sensor being operable to capture portions of a fingerprint image as a finger is slid over the sensor;

wherein the sensor is disposed adjacent to a perimeter edge of a touch screen of the touch screen device;

a light source for illuminating an area of the finger;

a motion detector comprised of a capacitive sensing element disposed within the touch screen of the touch screen device;

wherein the motion detector is configured to detect finger movement as the finger is slid over an upper surface of the touch screen; and

an image processor attached to the substrate and coupled to the sensor and the motion detector for processing at least two captured portions of the fingerprint image and further generating a processed fingerprint image in accordance with the finger movement determined by the motion detector;

an optical lens system for directing light to the finger and for directing reflected light towards the sensor, wherein the optical element comprises a lens and a light guide that each has an upper surface that is co-planar with the upper surface of the touch screen.

2. The fingerprint sensing module of claim 1, wherein the light guide is a linear array light pipe for directing a reflection of the fingerprint image unto the sensor.

3. The fingerprint sensing module of claim 1, wherein the optical lens system comprises a low profile optical element having a z-height less than 2 mm.

4. The fingerprint sensing module of claim 1, wherein the optical lens system comprises a low profile optical element that is fabricated by an etching process.

5. The fingerprint sensing module of claim 1, wherein the optical lens system comprises a low profile optical element device comprised of a fiber lens.

6. The fingerprint sensing module of claim 1, wherein the motion detector further comprises a motion computing circuit coupled to the capacitive sensing element, wherein the motion computing circuit determines the finger movement or displacement as the finger is slid over the touch screen.

7. The finger sensing module of claim 1 wherein the sensor is disposed adjacent to a perimeter edge of the touch screen.

8. The fingerprint sensing module of claim 1, wherein the substrate is a flexible circuit.

9. A handheld communications device, comprising:

a touch screen comprising an upper surface for sliding a finger thereacross and an apposed bottom surface;

a substrate;

a sensor attached to the substrate and disposed adjacent to a perimeter edge of the touch screen to capture portions of a fingerprint image as the finger is slid over the touch screen;

a light source for illuminating an area of the finger,

a motion detector comprised of a capacitive sensing element disposed within the touch screen wherein the motion detector is attached to the substrate and is configured to detect finger movement as the finger is slid over the touch screen; and

an image processor coupled to the sensor and the motion detector for processing at least two captured portions of the fingerprint image and further generating a processed fingerprint image in accordance with the finger movement determined by the motion detector;

an optical lens system for directing light to the finger and for directing reflected light towards the sensor, wherein the optical element comprises a lens and a light guide that each has an upper surface that is co-planar with the upper surface of the touch screen.

10. The handheld communications device of claim 9, wherein the touch screen is part of a housing of a portable electronic device comprising at least one of glass and plastic.

11. The handheld communications device of claim 9, wherein the sensor comprises at least one linear sensor array to capture portions of a fingerprint image as a finger is slid over the sensor.

12. The handheld communications device of claim 9, wherein the optical lens system is a low profile optical element having a z-height less than 2 mm.

13. The handheld communications device of claim 9, wherein the handheld communications device is configured to display a visual cue that assists a user where to place one'"'"'s finger and how to slide one'"'"'s finger across the optical lens.

14. The handheld communications device of claim 9, wherein the motion detector further comprises a motion computing circuit coupled to the capacitive sensing element, wherein the motion computing circuit determines a rate of the finger movement as the finger is slid over the touch screen.

15. A fingerprint sensing method for a touch screen device, comprising:

emitting illumination light onto a finger as the finger is slid over a touch screen of the touch screen device, wherein the illumination is emitted from a light source that is dedicated to fingerprint sensing;

capturing portions of a fingerprint image as the finger is slid over a sensor, said sensor being disposed adjacent to a perimeter edge of the touch screen;

detecting a rate of movement of the finger as the finger is in contact with and moving over a capacitive sensing element of the touch screen device; and

generating a finger print image by processing at least two portions of the fingerprint image captured by the sensor in accordance to a rate of the finger'"'"'s movement over the touch screen device.

16. A fingerprint sensing method of claim 15, further comprising determining the rate of finger'"'"'s movement by a motion computing circuit as the finger is in contact with the capacitive sensing element of the touch screen device.

17. A fingerprint sensing method of claim 15, further comprising processing at least two portions of the fingerprint image and subsequently combining portions of the fingerprint image into a complete fingerprint in accordance with the rate of the finger'"'"'s movement.