Capacitive touch screen with noise suppression

• US 9,823,784 B2
• Filed: 04/10/2009
• Issued: 11/21/2017
• Est. Priority Date: 04/10/2008
• Status: Active Grant

• Current Assignee: Neodrón Limited (Atlantic IP Services Limited), QRG Limited (Microchip Technology Incorporated)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Sleeman, Peter, Brunet, Samuel, Trend, Matthew, Philipp, Harald
• Primary Examiner(s): Mengistu, Amare
• Assistant Examiner(s): STEPP JONES, SHAWNA T
• Application Number:
  US12/421,705
• Publication Number:
  US 20100044122A1
• Time in Patent Office: 3,147 Days
• Field of Search: 178 18, 345173
• CPC Class Codes: G01B 2210/58 Wireless transmission of information between a sensor or probe and a control or evaluation unit
• CPC Class Codes: G01B 7/003 for measuring position, not involving coordinate determination coordinate measuring G01B7/004
• CPC Class Codes: G01D 5/2405 by varying dielectric
• CPC Class Codes: G06F 1/16 Constructional details or arrangements
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• 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 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• 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: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H05K 1/0296 Conductive pattern lay-out details not covered by sub groups H05K1/02 - H05K1/0295 H05K1/11 takes precedence; lay-out adapted to mounted component configuration H05K1/18

Abstract

A capacitive touch sensor wherein the touch sensitive panel has drive electrodes arranged on the lower side of a substrate and sense electrodes arranged on the upper side. The drive electrodes are shaped and dimensioned to substantially entirely cover the touch sensitive area with individual drive electrodes being separated from each other by small gaps, the gaps being so small as to be practically invisible. The near blanket coverage by the drive electrodes also serves to screen out interference from noise sources below the drive electrode layer, such as drive signals for an underlying display, thereby suppressing noise pick-up by the sense electrodes that are positioned above the drive electrodes.

Claims

1. A sensor comprising:

a substrate; and

a sensing region configured to sense a position of an object within the sensing region, the sensing region comprising;

a plurality of drive electrodes disposed on a first side of the substrate in a first layer; and

a plurality of sense electrodes disposed on a second side of the substrate in a second layer so that the sense electrodes intersect the drive electrodes at a plurality of intersections offset by a thickness of the substrate, wherein the plurality of drive electrodes are substantially area filling within the sensing region relative to the plurality of sense electrodes;

wherein a gap between adjacent sense electrodes has a width that is at least three-fifths of the pitch of the sense electrodes;

wherein the sensing region further comprises a plurality of isolated conductive elements disposed on the second side of the substrate between the sense electrodes so that, together, the plurality of sense electrodes and the plurality of isolated conductive elements are substantially area filling within the sensing region relative to the plurality of sense electrodes.

2. A computer-readable non-transitory storage media embodying logic that is configured when executed to:

sense a position of an object within a sensing region, the sensing region comprising;

a plurality of drive electrodes disposed on a first side of a substrate in a first layer; and

a plurality of sense electrodes disposed on a second side of the substrate in a second layer so that the sense electrodes intersect the drive electrodes at a plurality of intersections offset by athickness of the substrate, wherein the plurality of drive electrodes are substantially area filling within the sensing region relative to the plurality of sense electrodes;

wherein a gap between adjacent sense electrodes has a width that is at least three-fifths of the pitch of the sense electrodes; and

communicate a capacitance sensed by the drive and sense electrodes and indicative of the position of the object within the sensing region;

wherein the sensing region further comprises a plurality of isolated conductive elements disposed on the second side of the substrate between the sense electrodes so that, together, the plurality of sense electrodes and the plurality of isolated conductive elements are substantially area filling within the sensing region relative to the plurality of sense electrodes.

3. A method comprising:

sensing a position of an object within a sensing region, the sensing region comprising;

a plurality of drive electrodes disposed on a first side of a substrate in a first layer; and

a plurality of sense electrodes disposed on a second side of the substrate in a second layer so that the sense electrodes intersect the drive electrodes at a plurality of intersections offset by a thickness of the substrate, wherein the plurality of drive electrodes are substantially area filling within the sensing region relative to the plurality of sense electrodes;

wherein a gap between adjacent sense electrodes has a width that is at least three-fifths of the pitch of the sense electrodes; and

communicating a plurality of signals resulting from a capacitance sensed by the drive and sense electrodes and indicative of the position of the object within the sensing region;

wherein the sensing region further comprises a plurality of isolated conductive elements disposed on the second side of the substrate between the sense electrodes so that, together, the plurality of sense electrodes and the plurality of isolated conductive elements are substantially area filling within the sensing region relative to the plurality of sense electrodes.