Apparatus and Associated Methods

• US 20130106774A1
• Filed: 08/16/2012
• Published: 05/02/2013
• Est. Priority Date: 10/26/2011
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Corporation
• Inventors: RADIVOJEVIC, Zoran, BEECHER, Paul, BOWER, Chris, ANDREW, Piers, HAQUE, Samiul, COTTON, Darryl
• Granted Patent: US 9,495,010 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2017/9606 using one electrode only per touch switch
• CPC Class Codes: H03K 2017/9613 using two electrodes per touch switch
• CPC Class Codes: H03K 2217/960765 Details of shielding arrangements
• CPC Class Codes: H03K 2217/96077 comprising an electrode which is floating
• CPC Class Codes: H03K 2217/960775 Emitter-receiver or "fringe" type detection, i.e. one or more field emitting electrodes and corresponding one or more receiving electrodes

Abstract

An apparatus including a processor and a memory including computer program code. The memory and the computer program code are configured to cause the apparatus to, for an array of capacitive touch sensors with a proximally positioned electrotactile layer, compare the capacitance associated with a capacitive touch sensor of the array against a respective detection threshold to determine whether or not a touch input has occurred at the capacitive touch sensor by a stylus in capacitive coupling proximity to the capacitive touch sensor. The detection threshold of one or more capacitive touch sensors of the array is set to be sufficient to inhibit the erroneous generation of a touch input signal at the one or more respective capacitive touch sensors caused by capacitive cross-coupling, via the electrotactile layer, to the capacitive touch sensor which is in capacitive coupling proximity to the stylus.

Claims

1. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to, for an array of capacitive touch sensors with a proximally positioned electrotactile layer,

compare the capacitance associated with a capacitive touch sensor of the array against a respective detection threshold to determine whether or not a touch input has occurred at the capacitive touch sensor by a stylus in capacitive coupling proximity to the capacitive touch sensor,

wherein the detection threshold of one or more capacitive touch sensors of the array is set to be sufficient to inhibit the erroneous generation of a touch input signal at the one or more respective capacitive touch sensors caused by capacitive cross-coupling, via the electrotactile layer, to the capacitive touch sensor which is in capacitive coupling proximity to the stylus.

2. The apparatus of claim 1, wherein the detection threshold of each capacitive touch sensor of the array is set to be sufficient to inhibit the erroneous generation of a touch input signal at the respective capacitive touch sensor.

3. The apparatus of claim 2, wherein the same detection threshold is set for each capacitive touch sensor of the array.

4. The apparatus of claim 2, wherein the detection threshold set for one capacitive touch sensor is different from the detection threshold set for another capacitive touch sensor.

5. The apparatus of claim 1, wherein the detection threshold is determined based on a peak capacitance associated with one or more sensors and filtering out lower capacitances associated with adjacent touch sensors.

6. The apparatus of claim 1, wherein the detection threshold is determined using a calibration application configured to provide targets associated with touch input.

7. The apparatus of claim 1, wherein the electrotactile layer comprises one or more apertures configured to reduce the capacitive cross-coupling.

8. The apparatus of claim 7, wherein the dimensions, positioning and/or shape of the one or more apertures reduce the capacitive cross-coupling.

9. The apparatus of claim 7, wherein the dimensions, positioning and/or shape of the one or more apertures are such that the material used to form the electrotactile layer does not completely overlap with any of the capacitive touch sensors.

10. The apparatus of claim 7, wherein the dimensions, positioning and/or shape of the one or more apertures are such that the electrotactile layer is able to couple capacitively to the stylus when the stylus is positioned to provide a touch input to a capacitive touch sensor.

11. The apparatus of claim 7, wherein the dimensions, positioning and/or shape of the one or more apertures are such that none of the material used to form the electrotactile layer is located directly above or below the capacitive touch sensors.

12. The apparatus of claim 7, wherein the dimensions, positioning and/or shape of the one or more apertures are such that the capacitive cross-coupling is insufficient to prevent detection of a touch input when the stylus is in proximity to a capacitive touch sensor.

13. The apparatus of claim 7, wherein the dimensions, positioning and/or shape of the one or more apertures are such that the capacitive cross-coupling causes a negligible variation in the capacitance of the capacitive touch sensors.

14. The apparatus of claim 1, wherein the capacitive touch sensors are self-capacitive touch sensors each comprising a single electrode, the stylus forming a capacitor with the single electrode when the stylus is in proximity to the capacitive touch sensor, and wherein capacitive coupling between the capacitive touch sensor and the stylus causes a variation in the capacitance of the single electrode.

15. The apparatus of claim 1, wherein the capacitive touch sensors are mutually-capacitive touch sensors each comprising transmitter and receiver electrodes configured to generate an electric field therebetween, the stylus interfering with the electric field when the stylus is in proximity to the capacitive touch sensor, and wherein capacitive coupling between the capacitive touch sensor and the stylus causes a variation in the capacitance of the receiver electrode.

16. The apparatus of claim 7, wherein the electrotactile layer comprises a plurality of apertures, each aperture configured to reduce the capacitive cross-coupling between one capacitive touch sensor and the electrotactile layer.

17. The apparatus of claim 7, wherein each aperture is configured to reduce the capacitive cross-coupling between multiple capacitive touch sensors and the electrotactile layer.

18. The apparatus of claim 1, wherein the apparatus comprises the array of capacitive touch sensors and the electrotactile layer.

19. The apparatus of claim 1, wherein the apparatus is one or more of the following:

an electronic device, a portable electronic device, a portable telecommunications device, a touchscreen display for any of the aforementioned devices, and a module for any of the aforementioned devices.

20. A method comprising, for an array of capacitive touch sensors with a proximally positioned electrotactile layer,

comparing the capacitance associated with a capacitive touch sensor of the array against a respective detection threshold to determine whether or not a touch input has occurred at the capacitive touch sensor by a stylus in capacitive coupling proximity to the capacitive touch sensor,

wherein the detection threshold of one or more capacitive touch sensors of the array is set to be sufficient to inhibit the erroneous generation of a touch input signal at the one or more respective capacitive touch sensors caused by capacitive cross-coupling, via the electrotactile layer, to the capacitive touch sensor which is in capacitive coupling proximity to the stylus.

21. A computer program, recorded on a carrier, the computer program comprising computer code configured to perform the method of claim 20.

22. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

place a capacitive touch sensor in an on state or an off state by controlling a potential applied to the capacitive touch sensor such that, in the on state, a first potential is applied to the capacitive touch sensor, and in the off state, a second potential is applied to the capacitive touch sensor, the capacitive touch sensor configured to enable the detection of a touch input when it is in the on state but not when it is in the off state; and

place an electrotactile layer, proximal to the touch sensor, in an on state or an off state by controlling a potential applied to the electrotactile layer such that, in the on state, a third potential is applied to the electrotactile layer, and in the off state, a fourth potential is applied to the electrotactile layer, the electrotactile layer configured to enable the provision of haptic feedback when it is in the on state but not when it is in the off state, wherein the first potential and fourth potential are periodic potentials, and wherein the first potential and fourth potential have substantially the same frequency, amplitude and phase when the capacitive touch sensor is in the on state whilst the electrotactile layer is in the off state to reduce capacitive cross-coupling caused by the proximity of the electrotactile layer to the capacitive touch sensor.

23. An apparatus comprising at least one processor and at least one memory including computer program code, the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus at least to:

place a capacitive touch sensor in an on state or an off state by controlling a potential applied to the capacitive touch sensor such that, in the on state, a first potential is applied to the capacitive touch sensor, and in the off state, a second potential is applied to the capacitive touch sensor, the capacitive touch sensor configured to enable the detection of a touch input when it is in the on state but not when it is in the off state; and

place an electrotactile layer, proximal to the capacitive touch sensor, in an on state or an off state by controlling a potential applied to the electrotactile layer such that, in the on state, a third potential is applied to the electrotactile layer, and in the off state, a fourth potential is applied to the electrotactile layer, the electrotactile layer configured to enable the provision of haptic feedback when it is in the on state but not when it is in the off state,

wherein the first potential and third potential are periodic potentials, and wherein the first potential is higher than the third potential when the capacitive touch sensor and electrotactile layer are in their respective on states at the same time to reduce charge transfer from the electrotactile layer to the capacitive touch sensor caused by the proximity of the electrotactile layer to the capacitive touch sensor.