Mutual capacitance touch sensing device

• US 8,743,060 B2
• Filed: 07/06/2009
• Issued: 06/03/2014
• Est. Priority Date: 07/06/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven Porter
• Primary Examiner(s): PHAM, VIET DAVID
• Application Number:
  US12/498,119
• Publication Number:
  US 20090273573A1
• Time in Patent Office: 1,793 Days
• Field of Search: 345156-173
• 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:

a flexible membrane;

a resistive switch disposed on one surface of the flexible membrane; and

a capacitive sensor disposed on an opposite surface of the flexible membrane opposite the switch,

the switch and the sensor having substantially matching conductive patterns so as to capacitively couple to form a sensing node.

2. The device of claim 1 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.

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

4. The device of claim 2, wherein each node of the device includes a touch sensor configured to detect a touch at the position of the node.

5. The device of claim 2, 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.

6. The device of claim 2, 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.

7. The device of claim 2, 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.

8. The device of claim 2 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.

9. The device of claim 2 comprising a click wheel.

10. The device of claim 2 incorporated into at least one of a mobile telephone, a digital media player, or a personal computer.

11. The device of claim 1 wherein

the switch comprises 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.

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

13. The device of claim 11, 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.

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

15. The device of claim 11, wherein at least one of the sensed touch or the sensed force triggers performance of a function of the device.

16. The device of claim 15, 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.

17. The device of claim 1, wherein the switch is configured to deform in response to a force applied thereto and the sensor is configured to sense touch.

18. The device of claim 17, wherein the switch comprises a dome switch having a force sensor and a conductive ring, the sensor comprises a touch sensor comprising 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.

19. The device of claim 1, 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.

20. The device of claim 19, wherein the second sensing node comprises a touch sensor configured to sense touch.

21. An input device, comprising:

a flexible membrane,

flexible circuitry associated with the flexible membrane, the flexible circuitry comprising;

multiple mutual capacitive sensors responsive to touch input, the multiple mutual capacitive sensors being mounted on the flexible membrane,

multiple resistive switches responsive to force input, the multiple resistive switches being mounted on the flexible membrane,

the flexible circuitry enabling sensing of force input signals associated with the multiple resistive switches and touch input signals associated with the multiple mutual capacitive sensors.

22. The input device of claim 21 wherein the flexible membrane comprises a first surface and a second surface, wherein at least some of the multiple mutual capacitive sensors are disposed on the first surface of the flexible membrane and wherein at least some of the multiple resistive switches are disposed on the second surface of the flexible membrane.

23. The input device of claim 21 wherein at least one of the mutual capacitive sensors and at least one of the resistive switches are coupled.