Multipoint Touch Surface Controller

• US 20090315851A1
• Filed: 08/27/2009
• Published: 12/24/2009
• Est. Priority Date: 05/02/2006
• Status: Abandoned Application

• Current Assignee: Brian Quentin Huppi, Christoph H. Krah, Steven P. Hotelling
• Original Assignee: Brian Quentin Huppi, Christoph H. Krah, Steven P. Hotelling
• Inventors: Huppi, Brian Quentin, Hotelling, Steven P., Krah, Christoph H.
• Application Number:
  US12/549,269
• Publication Number:
  US 20090315851A1
• 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 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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 multipoint touch surface controller is disclosed herein. The controller includes an integrated circuit including output circuitry for driving a capacitive multi-touch sensor and input circuitry for reading the sensor. Also disclosed herein are various noise rejection and dynamic range enhancement techniques that permit the controller to be used with various sensors in various conditions without reconfiguring hardware.

Claims

1. An offset compensation circuit for use in conjunction with a capacitive touch sensor, wherein the capacitive touch sensor is operated by measuring capacitive coupling of a drive waveform from a drive electrode to a sense electrode, the offset compensation circuit comprising:

a programmable offset digital to analog converter adapted to generate an offset signal corresponding to a static component of the capacitive coupling between the drive electrode and the sense electrode; and

a subtractor circuit configured to subtract the offset signal from a measured signal indicative of the capacitive coupling between the at least one drive electrode and the at least one sense electrode.