PIEZO-BASED ACOUSTIC AND CAPACITIVE DETECTION

• US 20110175813A1
• Filed: 01/20/2010
• Published: 07/21/2011
• Est. Priority Date: 01/20/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Richardson, Andew Ross, Sarwar, Mushtaq A., Leung, Omar Sze, Pance, Aleksandar, Bilbrey, Brett
• Granted Patent: US 8,624,878 B2
• Time in Patent Office: Days
• US Class Current: 345/168
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/043 using propagating acoustic waves
• CPC Class Codes: G06F 3/0433 in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: H04R 2410/00 Microphones
• CPC Class Codes: H04R 2410/05 Noise reduction with a separate noise microphone

Abstract

One particular implementation conforming to aspects of the present disclosure takes the form of an input device for a computing system. The input device includes a input surface on which one or more input characters are shown and one or more sensors to detect which input character is pressed or selected by the user. In one example, the input device may include one or more piezo-electric sensors that detect an acoustic pulse created when the user taps on the input surface to indicate a selected input. Each character of the input surface of the input device creates a different acoustic pulse signature when tapped such that, upon detection and receiving of the acoustic pulse at the piezo-electric sensors, the input device or computer system may compare the received pulse to a database of stored pulse signatures to determine which character on the surface of the input device was tapped by the user.

Claims

1. An input device for a computing system comprising:

an input surface;

a capacitive sensor associated with the input surface configured to detect a location of an input on the input surface; and

a piezoelectric sensor configured to detect an acoustic signature created from the input, wherein the acoustic signature is compared to a database of reference acoustic signatures that indicate the location of the input to the input device.

2. The input device of claim 1 further comprising:

a second piezoelectric sensor for detecting a second acoustic signature created from the input; and

a second database of reference acoustic signatures, wherein the second acoustic signature is compared to the second database to determine the location of the input on the input surface.

3. The input device of claim 1 further comprising:

one or more tuning features configured to alter the acoustic signature created from the input.

4. The input device of claim 3 wherein the one or more tuning features comprise one or more openings in the input device.

5. The input device of claim 1 further comprising:

one or more pressure sensors configured to detect a dampening force applied to the input surface of the input device.

6. The input device of claim 5 wherein the acoustic signature is compared to a database of dampened reference acoustic signatures that indicate the location of the input to the input device when a dampening force is applied to the input surface.

7. The input device of claim 1 further comprising:

at least one microphone configured to detect ambient noise, wherein the detected ambient noise is subtracted from the acoustic signature prior to comparison to the database of reference acoustic signatures.

8. The input device of claim 1 further comprising:

one or more proximity sensors configured to detect the presence of an input on the input surface of the input device.

9. A method for detecting an input applied to a surface of an input device of a computing system comprising:

receiving a first acoustic pulse at a first piezoelectric sensor;

comparing the first acoustic pulse to a first database comprising a plurality of first reference acoustic signatures;

receiving a second acoustic pulse at a second piezoelectric sensor; and

comparing the second acoustic pulse to a second database comprising a plurality of second reference acoustic signatures, wherein the plurality of first reference acoustic signatures and the plurality of second reference acoustic signatures provide an indication of the location of the input on the surface of the input device.

10. The method of claim 9 further comprising:

detecting a change in a capacitive field on the surface of the input device in response to the input; and

determining the location on the surface of the input by locating the change in the capacitive field.

11. The method of claim 9 further comprising:

detecting a damping force applied to the surface of the input device; and

comparing the first acoustic pulse and the second acoustic pulse to a third database comprising a plurality of damped acoustic signatures.

12. The method of claim 9 further comprising:

detecting ambient noise present near the input device; and

subtracting the detected ambient noise from the first acoustic pulse and the second acoustic pulse.

13. The method of claim 9 further comprising:

utilizing a proximity sensor to detect the presence of an object near the surface of the input device.

14. The method of claim 13 further comprising:

activating at least the first piezoelectric sensor in response to detecting the presence of the object near the surface of the input device; and

deactivating at least the first piezoelectric sensor when the presence of the object near the surface of the input device is no longer detected.

15. The method of claim 9 further comprising:

tapping on the surface of the input device at discrete spatial intervals; and

storing at least the acoustic pulse resulting from the tapping operation received at the first piezoelectric sensor in the first database; and

associating the stored acoustic pulse with a segment of the surface of the input device corresponding to the input applied to the surface.

16. A computing system comprising:

an input device comprising an input surface and configured to receive an input to the computing system from a user;

a computer-readable storage device configured to store a database of reference acoustic signatures;

a capacitive sensor configured to detect a location of the input on the input surface; and

a piezoelectric sensor configured to detect the at least one acoustic signature representing the input, wherein the detected at least one acoustic signature is compared to the database to determine the location of the input.

17. The system of claim 16 further comprising:

a pressure sensor configured to detect a dampening force applied to the input surface of the input device.

18. The system of claim 16 further comprising:

a proximity sensor configured to detect the presence of an input on the input surface of the input device.

19. The system of claim 16 further comprising:

a microphone configured to detect ambient noise near the input device.

20. The system of claim 16 wherein the input surface comprises one or more input characters associated with one or more segments of the input surface, such that the user presses at least one of the one or more input characters to provide the input.