Method of controlling an electronic device

1. A method of controlling an electronic device, the electronic device comprising a control unit, a display unit defining a first functional area, and a fingerprint sensor defining a second functional area, wherein the second functional area at least partly overlaps with the first functional area, wherein the method comprises:

detecting, using the fingerprint sensor and the control unit, a user's finger within a portion of the second functional area of the fingerprint sensor, the portion defining a sensing area for the fingerprint sensor, the sensing area arranged at a first position within the second functional area of the fingerprint sensor;

acquiring, at the sensing area arranged at the first position and using the fingerprint sensor, a fingerprint image of a finger of the user;

authenticating, using the control unit, the user based on the acquired fingerprint image;

receiving, at the control unit, a request to redefine the position of the sensing area within the second functional area;

determining, using the control unit, a second position for the sensing area only if the user has been successfully authenticated; and

setting the second position for the sensing area,

wherein, before the user is authenticated, the sensing area is not displayed on the display unit such that the set position of the sensing area is hidden, and

wherein authentication of the user after setting the second position for the sensing area is based on an image of the fingerprint of the user acquired at the second position such that authentication is based on both the fingerprint of the user and the second position.

2. The method according to claim 1 , further comprising:

receiving an instruction for setting the first position for the sensing area.

3. The method according to claim 1 , wherein receiving an instruction to redefine the position of the sensing area comprises at least one of:

determining if a duration for detection of the finger within sensing area exceeds a first threshold; and

determining if a pressure applied by the users finger within the sensing area exceeds a second threshold.

4. The method according to claim 1 , wherein determining the second position for the sensing area comprises:

determining, using the fingerprint sensor and the control unit, a position of the user's finger within the second functional area.

5. The method according to claim 4 , wherein determining the position of the user's finger comprises:

acquiring, using the fingerprint sensor, one or a plurality of fingerprint images at the second functional area at least partly outside of the sensing area.

6. The method according to claim 4 , wherein the display unit is a touch display screen and determining the position of the user's finger comprises:

determining, using the display unit and the control unit, a position of the user's finger within the first functional area of the touch display screen; and

correlating a coordinate system for the first functional area with a coordinate system for the second functional area for determining the position of the user's finger within the second functional area.

7. The method according to claim 4 , further comprising:

identifying, using the control unit a size of the user's finger; and

defining a size of the sensing area based on the size of identified size of the user's finger.

8. The method according to claim 1 , wherein the first position is different from the second position.

9. The method according to claim 1 , wherein the second position is set only if the second position differs from the first position with more than a distance threshold.

10. The method according to claim 1 , wherein the second functional area constitutes at least 70% of the first functional area.

11. The method according to claim 1 , wherein the fingerprint sensor comprises a plurality of ultrasonic transducers in the vicinity of a circumference of the second functional area, and the method further comprises:

operating a selected portion of the plurality of ultrasonic transducers for acquiring the fingerprint image.

12. The method according to claim 11 , wherein the portion of the plurality of ultrasonic transducers are selected based on the first or the second position of the sensing area.

13. The method according to claim 1 , wherein the display unit is adapted to display a graphical user interface (GUI), wherein the method comprises:

providing, using the GUI, an instruction to the user for repositioning of the finger for determining the second position for the sensing area.

14. An electronic device, comprising:

a control unit;

a display unit defining a first functional area; and

a fingerprint sensor defining a second functional area, wherein the second functional area at least partly overlaps with the first functional area,

wherein the electronic device is adapted to:

detect, using the fingerprint sensor and the control unit, a user's finger within a portion of the second functional area of the fingerprint sensor, the portion defining a sensing area for the fingerprint sensor, the sensing area arranged at a first position within the second functional area of the fingerprint sensor;

acquire, at the sensing area arranged at the first position and using the fingerprint sensor, a fingerprint image of a finger of the user;

authenticate, using the control unit, the user based on the acquired fingerprint image;

receive, at the control unit, a request to redefine the position of the sensing area within the second functional area;

determine, using the control unit, a second position for the sensing area only if the user has been successfully authenticated; and

set the second position for the sensing area,

wherein, before the user is authenticated, the sensing area is not displayed on the display unit such that the set position of the sensing area is hidden, and

wherein authentication of the user after setting the second position for the sensing area is based on an image of the fingerprint of the user acquired at the second position such that authentication is based on both the fingerprint of the user and the second position.

15. The electronic device according to claim 14 , wherein the display unit is a touch display screen and determine the position of the user's finger comprises:

determining, using the display unit and the control unit, a position of the user's finger within the first functional area of the touch display screen; and

correlating a coordinate system for the first functional area with a coordinate system for the second functional area for determining the position of the user's finger within the second functional area.

16. The electronic device according to claim 14 , wherein the fingerprint sensor is adapted to employ one of ultrasonic or capacitive sensing technology.

17. The electronic device according to claim 14 , wherein the fingerprint sensor comprises a plurality of ultrasonic transducers in the vicinity of a circumference of the second functional area, and the electronic device is adapted to:

operate a selected portion of the plurality of ultrasonic transducers for acquiring the fingerprint image.

18. The electronic device according to claim 14 , wherein the electronic device is at least one of a tablet and a mobile phone.

19. A computer program product comprising a non-transitory computer readable medium having stored thereon computer program means for a control unit adapted for controlling an electronic device, the electronic device further comprising a display unit defining a first functional area, and a fingerprint sensor defining a second functional area, wherein the second functional area at least partly overlaps with the first functional area,

wherein the computer program product comprises:

code for detecting, using the fingerprint sensor and the control unit, for a user's finger within a portion of the second functional area of the fingerprint sensor, the portion defining a sensing area for the fingerprint sensor, the sensing area arranged at a first position within the second functional area of the fingerprint sensor;

code for acquiring, at the sensing area arranged at the first position and using the fingerprint sensor, a fingerprint image of a finger of the user;

code for authenticating, using the control unit, the user based on the acquired fingerprint image;

code for receiving, at the control unit, a request to redefine the position of the sensing area within the second functional area;

code for determining, using the control unit, a second position for the sensing area only if the user has been successfully authenticated; and

code for setting the second position for the sensing area,

wherein, before the user is authenticated, the sensing area is not displayed on the display unit such that the set position of the sensing area is hidden, and

wherein authentication of the user after setting the second position for the sensing area is based on an image of the fingerprint of the user acquired at the second position such that authentication is based on both the fingerprint of the user and the second position.