Electrode configurations for projected capacitive touch screen

• US 8,279,194 B2
• Filed: 05/22/2009
• Issued: 10/02/2012
• Est. Priority Date: 05/22/2009
• Status: Active Grant

• Current Assignee: Elo Touch Solutions, Inc.
• Original Assignee: Elo Touch Solutions, Inc.
• Inventors: Kent, Joel C., Aroyan, James L.
• Primary Examiner(s): Mengistu, Amare
• Assistant Examiner(s): PATEL, PREMAL R
• Application Number:
  US12/471,194
• Publication Number:
  US 20100295814A1
• Time in Patent Office: 1,229 Days
• Field of Search: 345168-174, 178/18.06
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

A projected capacitive touch screen is provided that comprises a substrate and electrodes. The substrate defines an active touch zone surrounded by edges. The active touch zone includes a central active zone and an acceleration zone that is located proximate to, and extends along, at least one of the edges. The electrodes are provided on the substrate and are organized into first and second sets of electrodes that are contained within a common plane on the substrate. The first set of electrodes is interlaced with the second set of electrodes in a non-overlapping pattern on the substrate. At least a subset of the electrodes each has an apex and a base and a non-uniform triangular shape that extends along a longitudinal axis between the apex and the base.

Claims

1. A projected capacitive touch screen, comprising:

a substrate that defines an active touch zone surrounded by edges, the active touch zone including a central active zone and an acceleration zone that is located proximate to, and extends along, at least one of the edges; and

electrodes provided on the substrate, the electrodes being organized into first and second sets of electrodes that are contained within a common plane on the substrate, the first set of electrodes being interlaced with the second set of electrodes in a non-overlapping pattern on the substrate, wherein at least a subset of the electrodes each has an apex and a base and a non-uniform triangular shape that extends along a longitudinal axis between the apex and the base, the subset of the electrodes being located such that at least a portion of the non-uniform triangular shape is located within the acceleration zone; and

wherein the non-uniform triangular shape and non-overlapping pattern provide edge acceleration to compensate for signal loss when a portion of a finger contact area moves beyond one of the edges outside the active touch zone.

2. The touch screen of claim 1, wherein the non-uniform triangular shape of at least one of the electrodes includes an electrode width that varies more rapidly near a perimeter of the active touch zone than a variation of the electrode width near a center of the active touch zone.

3. The touch screen of claim 1, wherein the electrodes within the subset of electrodes include an intermediate body segment located between the apex and base, and wherein the non-uniform triangular shape includes a first pitch proximate to the base and a different second pitch along the intermediate body segment, the pitch representing a rate of change in a width of the electrode per unit of distance along the longitudinal axis of the electrode.

4. The touch screen of claim 1 wherein the acceleration zone extends up to 20 mm from the corresponding edge.

5. The touch screen of claim 1, wherein the non-uniform triangular shape has at least one of i) an intra-electrode pitch change, and ii) a difference in widths between the electrodes that are interiorly located within the active touch zone and the electrodes that are laterally located relative to the active touch zone.

6. The touch screen of claim 1, wherein the apex includes at least one of a triangular contour, a multi-segment contour, a rounded contour with a concave end, and a rounded contour with a pointed end.

7. The touch screen of claim 1, wherein the non-uniform triangular shape includes a step change to a smaller area in a segment of the corresponding electrode proximate to the edge.

8. The touch screen of claim 1, the electrodes including a first subset of at least two of the electrodes extending along the acceleration zone proximate one of the edges, and a second subset of at least two of the electrodes extending through the central active zone, the electrodes in the first subset having a smaller electrode area than an electrode area of the electrodes in the second subset.

9. The touch screen of claim 1, wherein the active touch screen includes opposed acceleration zones located on opposite top and bottom sides of the central active area, the first and second sets of electrodes including electrodes that extend through the central active area such that the apexes and bases are located in the opposed acceleration zones.

10. The touch screen of claim 1, wherein the longitudinal axes of the electrodes are oriented to extend in a common direction as opposed lateral edges of the touch screen, each of the electrodes having an electrode area which is a function of a spacing of the electrode from the lateral edges.

11. The touch screen of claim 1, wherein the longitudinal axes of the electrodes are oriented to extend in a common direction as opposed lateral edges of the touch screen, each of the electrodes having an electrode area which is a function of a position of the electrode from the lateral edges.

12. A projected capacitive touch screen, comprising:

a substrate that defines an active touch zone surrounded by edges, the active touch zone including a central active zone and an acceleration zone that is located proximate to, and extends along, at least one of the edges; and

electrodes provided on the substrate, the electrodes being organized into first and second sets of electrodes that are contained within a common plane on the substrate, the first set of electrodes being interlaced with the second set of electrodes in a non-overlapping pattern on the substrate, wherein at least a subset of the electrodes each has opposed non-parallel first and second sides, the subset of the electrodes each having an apex segment, a base segment and an intermediate body segment therebetween, wherein the first side has a first pitch in the intermediate segment and a second pitch in at least one of the apex and base segments, the subset of the electrodes being located such that at least one of the apex and base segments is located within the acceleration zone;

wherein a non-uniform triangular shape of the electrodes and the non-overlapping pattern provide edge acceleration to compensate for signal loss when a portion of a finger contact area moves beyond one of the edges outside the active touch zone.

13. The touch screen of claim 12, wherein at least one of the electrodes includes an electrode width that varies more rapidly near a perimeter of the active touch zone than a variation of the electrode width near a center of the active touch zone.

14. The touch screen of claim 12, wherein the pitch represents a rate of change in a width of the electrode per unit of distance along a longitudinal axis of the electrode.

15. The touch screen of claim 12, wherein the acceleration zone extends up to 20 mm from the corresponding edge.

16. The touch screen of claim 12, wherein the electrodes that are interiorly located within the active touch zone have a different width than electrodes that are laterally located relative to the active touch zone.

17. The touch screen of claim 12, wherein the apex segment includes at least one of a triangular contour, a multi-segment contour, a rounded contour with a concave end, and a rounded contour with a pointed end.

18. The touch screen of claim 12, the electrodes including a first subset of at least two of the electrodes extending along the acceleration zone proximate one of the edges, and a second subset of at least two of the electrodes extending through the central active zone, the electrodes in the first subset having a smaller electrode area than an electrode area of the electrodes in the second subset.

19. An electronic device, comprising:

a processor, memory storing instructions to control operation of the processor, and a display for presenting information to a user, the display including a projected capacitive touch screen that comprises;

a substrate that defines an active touch zone surrounded by edges, the active touch zone including a central active zone and an acceleration zone that is located proximate to, and extends along, at least one of the edges;

electrodes provided on the substrate, the electrodes being organized into first and second sets of electrodes that are contained within a common plane on the substrate, the first set of electrodes being interlaced with the second set of electrodes in a non-overlapping pattern on the substrate, wherein at least a subset of the electrodes each has an apex and a base and a non-uniform triangular shape that extends along a longitudinal axis between the apex and the base, the subset of the electrodes being located such that at least a portion of the non-uniform triangular shape is located within the acceleration zone;

wherein the non-uniform triangular shape and non-overlapping pattern provide edge acceleration to compensate for signal loss when a portion of a finger contact area moves beyond one of the edges outside the active touch zone.

20. The touch screen of claim 19, wherein the apex includes at least one of a triangular contour, a multi-segment contour, a rounded contour with a concave end, and a rounded contour with a pointed end.