Flexible transparent touch sensing system for electronic devices

• US 7,030,860 B1
• Filed: 10/08/1999
• Issued: 04/18/2006
• Est. Priority Date: 10/08/1999
• Status: Expired due to Term

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Day, Shawn P., Hsu, Andrew C., Gillespie, David, Schediwy, Richard
• Primary Examiner(s): Awad, Amr A.
• Assistant Examiner(s): ABDULSELAM, ABBAS I
• Application Number:
  US09/415,481
• Time in Patent Office: 2,384 Days
• Field of Search: 345/173, 345/172, 345/156, 345/179, 345/174, 345/18.05, 345/18.06, 345/176, 178/18.01, 178/18.09, 178/19.01, 178/20.01, 178/18.04, 178/18.05, 178/18.06, 341/33, 341/34, 200/211, 463/37, 173/18.01
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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

Abstract

A transparent, capacitive sensing system particularly well suited for input to electronic devices is described. The sensing system can be used to emulate physical buttons or slider switches that are either displayed on an active display device or printed on an underlying surface. The capacitive sensor can further be used as an input device for a graphical user interface, especially if overlaid on top of an active display device like an LCD screen to sense finger position (X/Y position) and contact area (Z) over the display. In addition, the sensor can be made with flexible material for touch sensing on a three-dimensional surface. Because the sensor is substantially transparent, the underlying surface can be viewed through the sensor. This allows the underlying area to be used for alternative applications that may not necessarily be related to the sensing system. Examples include advertising, an additional user interface display, or apparatus such as a camera or a biometric security device.

Claims

1. A transparent capacitive touch sensing system comprising:

a substrate;

a sensory array disposed on the substrate and comprising a plurality of substantially transparent conductive traces disposed along a first axis, the sensory array covering a portion of the substrate, wherein the sensory array is configured to sense capacitively the input object along a second axis;

a substantially transparent and electrically conductive ground plane configured to shield electrically a bottom of said sensory array opposite the input object; and

a sensing device for detecting capacitance changes on said sensory array.

2. The system of claim 1, further including a position detector for determining a position of said input object near said sensory array.

3. The system of claim 1, further including a system that recognizes tap gestures.

4. The system of claim 1, wherein said substrate is a flexible, transparent substrate.

5. The system of claim 1, wherein said substrate is a rigid, transparent substrate.

6. The system of claim 1, wherein said sensory array is atop a display device.

7. The system of claim 6, wherein said display device is a liquid crystal display.

8. The system of claim 1, wherein said sensory array is atop a fingerprint sensor.

9. The system of claim 1, wherein said sensory array is atop a passive graphic underlay.

10. A transparent capacitive touch sensing system comprising:

a substantially transparent two-dimensional sensory array consisting of a plurality of substantially transparent conductive traces in an X axis and a plurality of substantially transparent conductive traces in a Y axis for sensing capacitive coupling between an input object and said sensory array along two axes, wherein a bottom of said sensory array opposite the input object is electrically shielded using a substantially transparent and electrically conductive ground plane;

a substantially transparent electrically insulating material separating said plurality of X traces from said plurality of Y traces; and

a sensing device for detecting capacitance changes on said sensory array.

11. A transparent capacitive touch sensing system comprising:

a substantially transparent two-dimensional sensory array consisting of a plurality of substantially transparent conductive traces in an X axis and a plurality of substantially transparent conductive traces in a Y axis for sensing capacitive coupling between an input object and said sensory array along two axes, wherein said conductive traces in the X axis and the Y axis are spaced such that conductive traces in the X axis substantially fill spaces between conductive traces in the Y axis to thereby form a substantially space-filling pattern across said sensory array;

a substantially transparent electrically insulating material separating said plurality of X traces from said plurality of Y traces; and

a sensing device for detecting capacitance changes on said sensory array.

12. The system of claim 11, wherein said sensory array comprises a plurality of layers having approximately the same index of refraction.

13. The system of claim 11, wherein said sensory array is atop a display device.

14. The system of claim 13, wherein said sensory array is directly disposed on the display device.

15. The system of claim 13, wherein said display device is a liquid crystal display.

16. The system of claim 11, wherein said sensory array is beneath a clear protective covering for a display device.

17. The system of claim 11 further comprising a substantially transparent adhesive disposed to fill gaps between the substantially transparent conductive traces.

18. The system of claim 11, wherein said sensory array is atop a fingerprint sensor.

19. The system of claim 11, wherein said sensory array is atop a passive graphic underlay.

20. A substantially transparent capacitive sensor comprising:

an active area configured to accept input from a conducive object, said active area including a plurality of substantially transparent conductive traces disposed in an X axis and a plurality of substantially transparent conductive traces disposed in a Y axis; and

a substantially transparent adhesive interposed between said conductive traces;

wherein said capacitive sensor has substantially uniform transmissivity within said active area.

21. The substantially transparent capacitive sensor of claim 20, wherein said plurality of substantially transparent conductive traces disposed in said X axis and said plurality of substantially transparent conductive traces disposed in said Y axis together substantially occupy said active area.

22. The substantially transparent capacitive sensor of claim 20, wherein said plurality of substantially transparent conductive traces disposed in said X axis and said plurality of substantially transparent conductive traces disposed in said Y axis are aligned to maximize transparency.

23. The substantially transparent capacitive sensor of claim 20 wherein the substantially transparent adhesive has an index of refraction similar to an index of refraction of said conductive traces.

24. The substantially transparent capacitive sensor of claim 20 wherein said conductive traces in the X axis and in the Y axis are spaced such that conductive traces in the X axis substantially fill spaces between conductive traces in the Y axis and vice versa to thereby form a substantially space-filling pattern across said sensory array.

25. The substantially transparent capacitive sensor of claim 20 wherein the substantially transparent adhesive has an index of refraction similar to an index of refraction of the conductive traces.

26. The capacitive sensor of claim 20, wherein the active area is atop a display device.

27. The system of claim 26, wherein said active area is directly disposed on the display device.

28. The system of claim 26, wherein said display device is a liquid crystal display.

29. A transparent capacitive touch sensor formed on a substrate for accepting an input from a conductive object, the system comprising:

a sensory array of substantially transparent conductive traces formed from a material having an index of refraction, the array comprising a first plurality of conductive traces disposed on said substrate in an first direction and a second plurality of conductive traces disposed on said substrate in a second direction different from said first direction, wherein the first and second pluralities of conductive traces are formed such that conductive traces in the first direction substantially fill spaces between conductive traces in the second direction and vice versa to thereby form a substantially space-filling pattern across said sensory array;

a substantially transparent adhesive interposed between said conductive traces and having an index of refraction similar to the index of refraction of the conductive traces to thereby provide a substantially uniform transmissivity across said sensory array; and

a sensing device electrically coupled to each of the conductive traces to thereby detect capacitance changes on said sensory array.

30. A substantially transparent capacitive sensor comprising:

an active area configured to accept input from a conductive object, said active area including a plurality of substantially transparent conductive traces disposed in an X axis and a plurality of substantially transparent conductive traces disposed in a Y axis, wherein said conductive traces in the X axis and in the Y axis are spaced such that conductive traces in the X axis substantially fill spaces between conductive traces in the Y axis and vice versa to thereby form a substantially space-filling pattern across said sensory array; and

wherein said capacitive sensor has substantially uniform transmissivity within said active area.