Capacitive sensing device for use in a keypad assembly

• US 8,305,359 B2
• Filed: 02/20/2009
• Issued: 11/06/2012
• Est. Priority Date: 08/05/2003
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Bolender, Robert J., Rubenson, Benjamin C.
• Primary Examiner(s): HALEY, JOSEPH R
• Application Number:
  US12/390,374
• Publication Number:
  US 20090160682A1
• Time in Patent Office: 1,355 Days
• Field of Search: None
• US Class Current: 345/174
• 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 3/0202 Constructional details or processes of manufacture of the input device
• 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
• CPC Class Codes: H01H 13/702 with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• CPC Class Codes: H01H 13/807 characterised by the spatial arrangement of the contact sites, e.g. superimposed sites
• CPC Class Codes: H01H 2209/082 transparent
• CPC Class Codes: H01H 2221/07 transparent
• CPC Class Codes: H01H 2225/002 superimposed
• CPC Class Codes: H01H 2227/004 Membrane
• CPC Class Codes: H01H 2239/006 Containing a capacitive switch or usable as such

Abstract

One embodiment in accordance with the present invention includes a capacitive sensing device for use in a keypad assembly of an electronic system. The capacitive sensing device includes a substantially transparent single sheet capacitive sensor. The substantially transparent single sheet capacitive sensor is configured to be disposed within the keypad assembly without requiring the formation of key post holes therethrough. Additionally, the substantially transparent single sheet capacitive sensor has a flexibility which enables desired tactile response during use of keys of the keypad assembly.

Claims

1. A capacitive sensor comprising:

a substantially transparent substrate;

a first substantially transparent capacitive sensor trace and a plurality of isolated shapes disposed above said substantially transparent substrate in a common layer and in a single disposition process, wherein each of said plurality of isolated shapes is substantially transparent;

insulator material disposed between at least two adjacent isolated shapes of said plurality of isolated shapes; and

conductive material disposed above a portion of said plurality of isolated shapes and electrically coupling said at least two adjacent isolated shapes such that said at least two adjacent isolated shapes become configured to comprise a second substantially transparent capacitive sensor trace, said conductive material electrically insulated from said first substantially transparent capacitive sensor trace by said insulator material.

2. The capacitive sensor of claim 1, wherein said substantially transparent substrate is comprised of polyethylene terephthalate (PET).

3. The capacitive sensor of claim 1, wherein said substantially transparent substrate is flexible.

4. The capacitive sensor of claim 1, wherein said insulator material overlaps said first substantially transparent capacitive sensor trace, and wherein said conductive material overlaps both said insulator material and said first substantially transparent capacitive sensor trace.

5. The capacitive sensor of claim 1, wherein said first substantially transparent capacitive sensor trace is arranged in a first direction, and wherein said second substantially transparent capacitive sensor trace is arranged in a second direction different from said first direction, said capacitive sensor further comprising:

a third substantially transparent capacitive sensor trace disposed above said substantially transparent substrate, said third substantially transparent capacitive sensor trace arranged in said first direction;

a second plurality of isolated shapes disposed above said substantially transparent substrate, said second plurality of isolated shapes configured to comprise a fourth substantially transparent capacitive sensor trace arranged in said second direction;

insulator material disposed between at least two adjacent isolated shapes of said second plurality of isolated shapes; and

conductive material electrically coupling said at least two adjacent isolated shapes of said second plurality of isolated shapes, said conductive material electrically insulated from said first and third substantially transparent capacitive sensor traces by said insulator material disposed between said at least two adjacent isolated shapes of said second plurality of isolated shapes.

6. The capacitive sensor of claim 1, wherein at least one of said first substantially transparent capacitive sensor trace and said second substantially transparent capacitive sensor trace is comprised of indium tin oxide (ITO).

7. The capacitive sensor of claim 1, wherein at least one of said first substantially transparent capacitive sensor trace and said second substantially transparent capacitive sensor trace is comprised of diamond shapes.

8. The capacitive sensor of claim 1, wherein said insulator material is substantially opaque.

9. The capacitive sensor of claim 1, wherein said insulator material is substantially transparent.

10. The capacitive sensor of claim 1, wherein said first substantially transparent capacitive sensor trace is formed using a lithographic process.

11. The capacitive sensor of claim 1, wherein said conductive material comprises at least one material selected from the group consisting of:

silver ink, carbon ink, and a mixture of silver ink and carbon ink.

12. The capacitive sensor of claim 1, wherein said capacitive sensor is coupled to sensing circuitry to comprise a capacitive sensing device.

28. The capacitive sensor of claim 1, wherein at least one of said first substantially transparent capacitive sensor trace and said second substantially transparent capacitive sensor trace comprises conductive material disposed around an opening.

29. The capacitive sensor of claim 28, wherein said conductive material disposed around said opening forms part of a lattice shape.

30. The capacitive sensor of claim 1, wherein said single common disposition process is selected from the disposition processes consisting of:

a screen printing process and a lithographic process.

13. A method for providing a capacitive sensor, said method comprising:

disposing a first substantially transparent capacitive sensor trace and a plurality of isolated shapes above a substantially transparent substrate in a common layer and in a single disposition process, wherein said first substantially transparent capacitive sensor trace is arranged in a first direction, and wherein each of said plurality of isolated shapes is substantially transparent;

disposing an insulator between at least two adjacent isolated shapes of said plurality of isolated shapes; and

electrically coupling said at least two adjacent isolated shapes with conductive material, such that said plurality of isolated shapes becomes configured to comprise a second substantially transparent capacitive sensor trace, wherein said second substantially transparent capacitive sensor trace is arranged in a second direction different from said first direction, said conductive material electrically insulated from said first substantially transparent capacitive sensor trace by said insulator.

14. The method for forming a capacitive sensor as recited in claim 13, wherein said substantially transparent substrate comprises a flexible substrate.

15. The method for forming a capacitive sensor as recited in claim 13, wherein said disposing said insulator comprises printing a dielectric to form said insulator.

16. The method for forming a capacitive sensor as recited in claim 13, wherein said disposing said first substantially transparent capacitive sensor trace above said substantially transparent substrate comprises:

disposing said first substantially transparent capacitive sensor trace using at least one process selected from the group consisting of;

printing and lithography processes.

31. The method as recited in claim 13, wherein said disposing a first substantially transparent capacitive sensor trace and a plurality of isolated shapes above a substantially transparent substrate in a common layer in a single common disposition process comprises:

disposing said first substantially transparent capacitive sensor and said plurality of isolated shapes above said substantially transparent substrate in a common layer utilizing a disposition process selected from the disposition processes consisting of;

a screen printing process and a lithographic process.

17. A capacitive sensor comprising:

a substantially transparent substrate;

a first pattern of conductive shapes adapted for forming a first set of capacitive sensor traces arranged along a first direction, said first pattern of conductive shapes disposed above said substantially transparent substrate and comprised of a substantially transparent material;

a second pattern of conductive shapes comprising a plurality of isolated shapes, said second pattern of conductive shapes comprised of said substantially transparent material, wherein said plurality of isolated shapes and said first pattern of conductive shapes are in a common layer that is disposed above said substantially transparent substrate in a single common disposition process;

a conductive material electrically coupling isolated shapes of said plurality of isolated shapes to form a second set of capacitive sensor traces arranged along a second direction different from said first direction; and

an insulator material disposed between said first pattern of conductive shapes and said conductive material, said insulator material configured to electrically insulate said first pattern of conductive shapes from said conductive material.

18. The capacitive sensor of claim 17, wherein said substantially transparent substrate is flexible.

19. The capacitive sensor of claim 17, wherein at least one of said first pattern of conductive shapes and said second pattern of conductive shapes is comprised of diamond-shapes.

20. The capacitive sensor of claim 17, wherein said first set of capacitive sensor traces and said second set of capacitive sensor traces are orthogonal to each other.

21. The capacitive sensor of claim 17, wherein said insulator material is substantially opaque.

32. The capacitive sensor of claim 17, wherein said single common disposition process is selected from the disposition processes consisting of:

a screen printing process and a lithographic process.

22. A method for providing a capacitive sensor, said method comprising:

disposing a first pattern of capacitive sensor traces and a second pattern of capacitive sensor traces above a substantially transparent substrate in a common layer and in a single common disposition process, said first pattern of capacitive sensor traces and said second pattern of capacitive sensor traces comprised of a substantially transparent material, disposing an insulator material over said substantially transparent substrate, wherein said insulator material overlaps said first pattern of capacitive sensor traces in said capacitive sensor; and

disposing a conductive material for electrically coupling portions of said second pattern of capacitive sensor traces over said substantially transparent substrate, wherein said conductive material overlaps both said insulator material and said first pattern of capacitive sensor traces in said capacitive sensor.

23. The method for providing said capacitive sensor as recited in claim 22, wherein said disposing said insulator material comprises:

disposing said insulator material over said first pattern of capacitive sensor traces.

24. The method for providing said capacitive sensor as recited in claim 22, wherein said disposing said insulator material comprises:

disposing a substantially opaque insulator, said substantially opaque insulator configured to electrically insulate said first pattern of capacitive sensor traces and said conductive material.

25. The method for providing said capacitive sensor as recited in claim 22, wherein said disposing said insulator comprises:

disposing a substantially transparent insulator, said substantially transparent insulator configured to electrically insulate said first pattern of capacitive sensor traces and said conductive material.

26. The method as recited in claim 22, wherein at least one of said first pattern of capacitive sensor traces and said second pattern of capacitive sensor traces comprises conductive material disposed around an opening.

27. The method as recited in claim 26, wherein said conductive material disposed around said opening forms part of a lattice shape.

33. The method as recited in claim 22, wherein said disposing a first pattern of capacitive sensor traces and a second pattern of capacitive sensor traces above a substantially transparent substrate in a common layer and in a single common disposition process comprises:

disposing said first pattern of capacitive sensor traces and said second pattern of capacitive sensor traces above said substantially transparent substrate in said common layer utilizing a disposition process selected from the disposition processes consisting of;

a screen printing process, and a lithographic process.