MUTUAL CAPACITANCE TOUCH SENSING DEVICE

• US 20090273573A1
• Filed: 07/06/2009
• Published: 11/05/2009
• Est. Priority Date: 07/06/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven Porter
• Granted Patent: US 8,743,060 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• 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 3/0362 with detection of 1D translations or rotations of an operating part of the device, e.g. scroll wheels, sliders, knobs, rollers or belts
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A mutual capacitive touch sensing device is disclosed. The device can include nodes for sensing a touch at the device and for sensing a force applied to the device. Some nodes can perform both touch and force sensing; while other nodes can perform touch sensing. The device can include distinct individual drive lines for driving the nodes and separate distinct individual sense lines for transmitting touch or force signals from the nodes. The nodes can form groups, where the nodes in each group can be coupled to the same drive line and to different sense lines and where each node in a group can be coupled to a node in a different group by the same sense line. Each node can be set up with a different combination of drive and sense lines coupled thereto. An example device can be a click wheel.

Claims

1. A touch sensing device comprising:

multiple drive lines;

multiple sense lines; and

multiple node groups, at least a first of the node groups comprising multiple nodes, each node in the first node group being associated with a first one of the drive lines, each node in the first node group being associated with different ones of the sense lines, and at least one node in each of the node groups being associated with a first one of the sense lines.

2. The device of claim 1, wherein the nodes of the device are disposed in a circular pattern.

3. The device of claim 1, wherein each node of the device includes a touch sensor configured to detect a touch at the position of the node.

4. The device of claim 1, wherein at least one node in the first node group includes a force sensor configured to detect a force applied at the position of the node.

5. The device of claim 1, wherein at least one node in the first node group includes a touch sensor configured to detect a touch at the position of the node and a force sensor configured to detect a force applied at the position of the node.

6. The device of claim 1, wherein each node of the device includes a drive electrode and a sense electrode configured to form a capacitance therebetween, the drive electrode coupled to a drive line to receive a voltage to drive the node and the sense electrode coupled to a sense line to transmit a capacitance signal indicative of a touch at the position of the node.

7. The device of claim 1 comprising a controller configured to drive the nodes of the device via the drive lines and to receive outputs from the nodes of the device via the sense lines.

8. The device of claim 1 comprising a click wheel.

9. The device of claim 1 incorporated into at least one of a mobile telephone, a digital media player, or a personal computer.

10. A touch sensing device comprising:

a node comprising

a touch sensor configured to sense a touch at the device, and

a switch configured to sense a force applied to the device, the switch comprising a force sensor associated with a center of the node and a conductive ring associated with a border of the node, the force sensor configured to receive the applied force and the conductive ring configured to couple to ground to reduce signal error introduced by the switch in association with the sensed touch.

11. The device of claim 10, wherein the switch comprises a dome switch.

12. The device of claim 10, wherein the signal error is introduced by a slight deformation of the switch, the slight deformation decreasing an air gap between a top of the switch and the force sensor so that capacitance increases.

13. The device of claim 12, wherein the slight deformation of the switch is a result of incidental contact from a device component proximate to the switch.

14. The device of claim 10, wherein at least one of the sensed touch or the sensed force triggers performance of a function of the device.

15. The device of claim 14, wherein the function comprises at least one of a play/pause function, a menu function, a forward function, a back function, or a scroll function.

16. A method, comprising:

measuring a capacitance at a node of a touch sensing device;

comparing the measured capacitance with a predetermined capacitance measurement at the node;

determining whether the comparison indicates a capacitance increase of the measured capacitance above the predetermined capacitance measurement; and

if so, identifying the node as having a force applied thereto.

17. The method of claim 16, comprising:

if the comparison indicates a capacitance increase, ignoring the measured capacitance.

18. The method of claim 16, comprising:

if the comparison indicates a capacitance increase, transmitting a signal indicative of the applied force at the node to a processor of the touch sensing device.

19. The method of claim 16, if the comparison indicates a capacitance decrease of the measured capacitance below the predetermined capacitance measurement, transmitting a signal indicative of a touch at the node to a processor of the touch sensing device.

20. A touch sensing device comprising:

a flexible membrane;

a first component of a sensing node disposed on one surface of the flexible membrane; and

a second component of the sensing node disposed on an opposite surface of the flexible membrane opposite the first component,

the first component and the second component having substantially matching conductive patterns so as to capacitively couple to form the sensing node.

21. The device of claim 20, wherein the first component of the sensing node comprises a switch configured to deform in response to a force applied thereto and the second component of the sensing node comprises a touch sensor configured to sense a touch thereat.

22. The device of claim 21, wherein the switch comprises a dome switch having a force sensor and a conductive ring, the touch sensor comprises a drive electrode and a sense electrode, and wherein the force sensor and the sense electrode have substantially matching conductive patterns and the conductive ring and the drive electrode have substantially matching conductive patterns.

23. The device of claim 20, comprising:

a second sensing node,

a first component of the second sensing node disposed on the one surface of the flexible membrane, and

a second component of the second sensing node disposed on the opposite surface of the flexible membrane opposite the first component of the second sensing node,

the first component and the second component of the second sensing node having substantially matching patterns as the first component and the second component of the sensing node so as to form a capacitance similar to a capacitance of the sensing node.

24. The device of claim 23, wherein the second sensing node comprises a touch sensor configured to sense a touch thereat.

25. A method comprising:

driving multiple nodes using a drive line associated with the nodes; and

sensing outputs of the nodes using different sense lines, a different sense line associated with a different node, an output of at least one of the nodes selectably including a signal associated with a force applied to the at least one node and a signal associated with a touch at the at least one node, and outputs of the remaining nodes including a signal associated with touches at the remaining nodes.