Proximity sensor

• US 9,081,572 B2
• Filed: 06/09/2014
• Issued: 07/14/2015
• Est. Priority Date: 07/26/2007
• Status: Active Grant

• Current Assignee: Neodrón Limited (Atlantic IP Services Limited)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Philipp, Harald, Snoad, Kevin
• Primary Examiner(s): NGUYEN, HOAI AN D
• Application Number:
  US14/299,032
• Publication Number:
  US 20140292716A1
• Time in Patent Office: 400 Days
• Field of Search: 324/663, 324/658, 324/649, 324/600, 324/688, 324/686, 324/679, 324/671, 324/669, 324/662, 324/661, 324/660, 702/57, 340/545.4, 340/545.2, 340/545.1, 340/541, 340/540, 381/74, 345/174, 345/173
• US Class Current: 1/1
• CPC Class Codes: G01R 27/26 Measuring inductance or capacitance; Measuring quality factor, e.g. by using the resonance method; Measuring loss factor; Measuring dielectric constants ; Measuring impedance or related variables
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/3231 Monitoring the presence, absence or movement of users
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G08B 13/08 by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2217/960705 Safety of capacitive touch and proximity switches, e.g. increasing reliability, fail-safe
• CPC Class Codes: H03K 2217/960725 Charge-transfer

Abstract

In one embodiment, a method includes monitoring detection by a sensing element of a key touch on a touch screen; determining an amount of time that has elapsed since the sensing element last detected a change of capacitance indicative of a key touch on the touch screen; and, if the amount of time that has elapsed exceeds a predetermined time duration, then initiating a particular function of an apparatus.

Claims

1. An apparatus comprising:

a sensing element; and

one or more computer-readable non-transitory storage media embodying logic that is operable when executed to;

determine an amount of time that has elapsed since the sensing element last detected a change of capacitance indicative of an object being in proximity to the sensing element; and

if the amount of time that has elapsed exceeds a predetermined time duration, then initiate a particular function of the apparatus.

2. The apparatus of claim 1, wherein the particular function comprises deactivation of measurement of changes in capacitance by the sensing element.

3. The apparatus of claim 1, wherein the particular function comprises recalibration of measurement of changes in capacitance by the sensing element.

4. The apparatus of claim 1, wherein the logic is further operable to calculate the predetermined time duration based on one of a plurality of power supply voltages or an output voltage of the sensing element.

5. The apparatus of claim 1, wherein the logic is further operable to calculate the predetermined time duration based on one of a plurality of delay multipliers determined by a polarity of a voltage pulse.

6. The apparatus of claim 1, wherein the particular function comprises turning off the apparatus.

7. The apparatus of claim 1, further comprising a control circuit.

8. The apparatus of claim 7, wherein the sensing element comprises a pattern of electrodes within a touch screen, the electrodes being coupled to the control circuit.

9. The apparatus of claim 8, wherein the electrodes comprise indium tin oxide (ITO).

10. A method comprising:

monitoring, by a control circuit, capacitance measurements of a sensing element of an apparatus;

determining an amount of time that has elapsed since the sensing element last detected a change of capacitance indicative of an object being in proximity to the sensing element; and

if the amount of time that has elapsed exceeds a predetermined time duration, then initiating a particular function of the apparatus.

11. The method of claim 10, wherein the particular function comprises deactivating measurement of changes in capacitance by the sensing element.

12. The method of claim 10, wherein the particular function comprises recalibrating measurement of changes in capacitance by the sensing element.

13. The method of claim 10, further comprising calculating the predetermined time duration based on one of a plurality of power supply voltages or an output voltage of the sensing element.

14. The method of claim 10, further comprising calculating the predetermined time duration based on one of a plurality of delay multipliers determined by a polarity of a voltage pulse.

15. The method of claim 10, wherein the particular function comprises turning off power to the apparatus.

16. A computer-readable non-transitory storage media embodying logic that is operable when executed to:

monitor capacitance measurements of a sensing element of an apparatus;

determine an amount of time that has elapsed since the sensing element last detected a change of capacitance indicative of an object being in proximity to the sensing element; and

if the amount of time that has elapsed exceeds a predetermined time duration, then initiate a particular function of the apparatus.

17. The media of claim 16, wherein the particular function comprises deactivation of measurement of changes in capacitance by the sensing element.

18. The media of claim 16, wherein the particular function comprises recalibration of measurement of changes in capacitance by the sensing element.

19. The media of claim 16, wherein the logic is further operable to calculate the predetermined time duration based on one of a plurality of power supply voltages or an output voltage of the sensing element.

20. The media of claim 16, wherein the logic is further operable to calculate the predetermined time duration based on one of a plurality of delay multipliers determined by a polarity of a voltage pulse.