Capacitive sensing and data input device power management

• US 6,850,229 B2
• Filed: 11/26/2001
• Issued: 02/01/2005
• Est. Priority Date: 09/07/2001
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Casebolt, Mark W., Garcia, Gino S.
• Primary Examiner(s): Tran, Henry N.
• Application Number:
  US09/991,667
• Publication Number:
  US 20030074587A1
• Time in Patent Office: 1,163 Days
• Field of Search: 345/156, 345/157, 345/163, 345/168, 345/173, 345/171, 345/161, 178/18.01, 178/18.03, 178/18.06, 178/18.1, 341/33, 341/34, 200/8.R, 200/211, 200/215, 200/600, 361/730, 361/734, 463/37, 463/46, 463/47
• US Class Current: 345/173
• 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 1/3259 Power saving in cursor control device, e.g. mouse, joystick, trackball
• CPC Class Codes: G06F 1/3271 Power saving in keyboard
• CPC Class Codes: G06F 3/0317 in co-operation with a patterned surface, e.g. absolute position or relative movement detection for an optical mouse or pen positioned with respect to a coded surface
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Capacitive proximity sensing is carried out by detecting a relative change in the capacitance of a “scoop” capacitor formed by a conductor and a surrounding ground plane. The conductor may be a plate provided in the form of an adhesive label printed with conductive ink. Charge is transferred between the “scoop” capacitor and a relatively large “bucket” capacitor, and a voltage of the bucket capacitor is applied to an input threshold switch. A state transition (e.g., from low to high, or high to low) of the input threshold switch is detected and a value (TouchVal) indicative of a number of cycles of charge transfer required to reach the state transition is determined. The presence or absence of an object or body portion in close proximity to or contact with a device can be determined by comparing TouchVal with a predetermined threshold value (TouchOff). TouchOff can be adjusted to take into account environmentally induced (non-touch related) changes in the capacitance of the scoop capacitor. Power management is provided in a user operated data input device utilizing proximity sensing and switching between three or more power states. Switching between the power states occurs based upon the presence or absence of input activity, and an operation instrumentality (e.g., a hand) in close proximity to or contact with the device. In an optical surface tracking cursor control device embodiment, switching to and from a BEACON state, which provides a reduced flash rate of a surface illuminating light source, is carried out based upon a detected presence or absence of a trackable surface.

Claims

1. An electronic device comprising a housing and a capacitive sensing system contained within said housing for sensing the presence of an operation instrumentality in contact with or close proximity to said electronic device and generating a signal indicative of an ON state wherein an operation instrumentality is in contact with or close proximity to said electronic device, and an OFF state wherein said operation instrumentality is not in contact with or close proximity to said electronic device, said capacitive sensing system comprising a conductive sensor plate in the form of a flexible label adhesively applied to an inside surface of said housing, said flexible label comprising a flexible substrate printed with patterns of plural lines of conductive material in plural discrete regions of the substrate, and with lines of conductive material electrically interconnecting said patterns to form a unified multi-region capacitive coupling structure of a single sensor, for extending the coverage area of the single sensor.

2. An electronic device according to claim 1, wherein said housing comprises a three-dimensional surface portion having a curvature that varies along orthogonal axes, said label being adhesively secured to said three-dimensional surface portion.

3. An electronic device according to claim 2, wherein said housing has plural interconnected parts to which said label is adhesively secured, a seam is formed between said interconnected parts and said label extends across said seam.

4. An electronic device according to claim 1, wherein said device is a hand-held data input device.

5. An electronic device according to claim 4, wherein said hand-held data input device is a cursor control device.