FINGERPRINT SENSING DEVICE

• US 20100220900A1
• Filed: 03/02/2009
• Published: 09/02/2010
• Est. Priority Date: 03/02/2009
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Orsley, Timothy James
• Granted Patent: US 8,605,960 B2
• Time in Patent Office: Days
• 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;

a light source for illuminating an area of the finger;

a motion detector for detecting finger movement as the finger is slid over the touch screen device; 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.

2. The fingerprint sensing module of claim 1, further comprising an optical element for directing the fingerprint image towards the sensor, wherein the optical element comprises a lens and a light guide.

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

4. The fingerprint sensing module of claim 2, wherein the optical element is a low profile optical element having a z-height less than 2 mm.

5. The fingerprint sensing module of claim 2, wherein the optical element is a low profile optical element that is fabricated by an etching process.

6. The fingerprint sensing module of claim 2, wherein the optical element is a low profile optical element device comprised of a fiber lens.

7. The fingerprint sensing module of claim 1, wherein the motion detector further comprises:

a capacitive sensing element; and

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 capacitive sensing element.

8. The finger sensing module of claim 7, wherein the capacitive sensing element is disposed within the touch screen device.

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

10. A fingerprint sensing 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 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 attached to the substrate for detecting 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.

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

12. The fingerprint sensing device of claim 10, 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.

13. The fingerprint sensing device of claim 10 further comprising an optical element for directing the fingerprint image towards the sensor, wherein the optical element comprises a lens and at least a light guide.

14. The fingerprint sensing device of claim 10, wherein the optical element is a low profile optical element having a z-height less than 2 mm

15. The fingerprint sensing device of claim 10, further comprising an indicator having a visual display to inform the user of the accuracy of the fingerprint sliding movement.

16. The fingerprint sensing device of claim 10, wherein the motion detector further comprises:

a capacitive sensing element; and

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 capacitive sensing element.

17. The finger sensing device of claim 16, wherein the capacitive sensing element is disposed at the bottom surface of the touch screen.

18. 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 a finger print sensing device;

capturing portions of a fingerprint image as the finger is slid over a sensor;

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.

19. A fingerprint sensing method of claim 18, further comprising determining the rate of finger'"'"'s movement by a motion computing circuit as the finger is ill contact with the capacitive sensing element of the touch screen device.

20. A fingerprint sensing method of claim 18, 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.