Force Imaging Input Device and System

• US 20090231305A1
• Filed: 05/22/2009
• Published: 09/17/2009
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: Brian Huppi, Steven P. Hotelling
• Original Assignee: Brian Huppi, Steven P. Hotelling
• Inventors: Hotelling, Steven P., Huppi, Brian Q.
• Granted Patent: US 9,069,404 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• 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 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• 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 3/0445 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
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A force imaging touch pad includes first and second sets of conductive traces separated by a spring membrane. When a force is applied, the spring membrane deforms moving the two sets of traces closer together. The resulting change in mutual capacitance is used to generate an image indicative of the amount or intensity of the applied force. A combined location and force imaging touch pad includes two sets of drive traces, one set of sense traces and a spring membrane. In operation, one of the drive traces is used in combination with the set of sense traces to generate an image of where one or more objects touch the touch pad. The second set of drive traces is used in combination with the sense traces and spring membrane to generate an image of the applied force'"'"'s strength or intensity.

Claims

1. A force imaging system comprising:

a substantially rigid member that receives a force input on a first surface and that includes a first conductive element disposed at a second surface;

a rigid member including a second conductive element spatially separated from the first conductive element through a mechanism by which the first and second conductive elements are brought into closer proximity when the force input is received by the first surface, such that the first and second conductive elements form first and second plates, respectively, of a plurality of capacitors with capacitances indicative of an intensity of the force input; and

a controller operatively coupled to the first and second conductive elements, wherein the controller measures the capacitances to obtain an image of the intensity of the force input.

2. The system of claim 1, wherein the first conductive element includes a first plurality of conductive traces oriented in a first direction.

3. The system of claim 2, wherein the second conductive element includes a second plurality of conductive traces oriented in a second direction, and intersections of the first and second conductive traces form the plurality of capacitors.

4. The system of claim 1 further comprising a deformable member disposed between the substantially rigid member and the rigid member, wherein the deformable member provides the mechanism by which the first and second conductive elements are brought into closer proximity when the force input is received by the first surface.

5. The system of claim 4 wherein the deformable member includes a dielectric membrane.

6. The system of claim 1, wherein the first conductive element is disposed on the second surface.

7. The system of claim 6, wherein the rigid member further includes a base layer having a third surface that faces the second surface of the substantially rigid layer, the second conductive element being disposed on the third surface.

8. The system of claim 7, further comprising a deformable dielectric membrane disposed between and contacting at least a portion of the first and second conductive elements.

9. The system of claim 1, wherein the controller includes a transmitter that transmits signals representing the image of the intensity of the force input.

10. The system of claim 9 further comprising a host processor that receives the signals and performs command and control actions based on the image of the intensity of the force input.

11. The system of claim 10, wherein the command and control actions include selecting an object displayed on a display unit.