CAPACITIVE SENSING DEVICE FOR USE IN A KEYPAD ASSEMBLY

• US 20090160682A1
• Filed: 02/20/2009
• Published: 06/25/2009
• Est. Priority Date: 08/05/2003
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Rubenson, Benjamin C., BOLENDER, Robert J.
• Granted Patent: US 8,305,359 B2
• Time in Patent Office: Days
• US Class Current: 341/33
• 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 disposed above said substantially transparent substrate;

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

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

conductive material electrically coupling said at least two adjacent isolated shapes, 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 is disposed above said first substantially transparent capacitive sensor trace, and wherein said conductive material is disposed above said insulator material.

5. The capacitive sensor of claim 1, wherein said first substantially transparent capacitive sensor trace is disposed 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, wherein said first, second, third, and fourth substantially transparent capacitive sensor traces enable sensing circuitry to utilize two dimensional capacitive sensing.

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.

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

providing a substantially transparent substrate;

disposing a first substantially transparent capacitive sensor trace above said substantially transparent substrate, wherein said first substantially transparent capacitive sensor trace is arranged in a first direction;

disposing a plurality of isolated shapes above said substantially transparent substrate, said plurality of isolated shapes 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;

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, 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 providing a substantially transparent substrate comprises providing a flexible substrate.

15. The method for forming a capacitive sensor as recited in claim 13, wherein said disposing an 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 a first substantially transparent capacitive sensor trace above said substantially transparent substrate and said disposing a plurality of isolated shapes above said substantially transparent substrate comprises:

disposing said first substantially transparent capacitive sensor trace above said substantially transparent substrate and said plurality of isolated shapes above said substantially transparent substrate using at least one process selected from the group consisting of;

printing and lithography processes.

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 adapted for forming a second set of capacitive sensor traces arranged along a second direction different from said first direction, 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;

a conductive material disposed to electrically couple isolated shapes of said plurality of isolated shapes to form said second set of capacitive sensor traces arranged along said second 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 are 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.

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

disposing a first pattern of capacitive sensor traces above a substantially transparent substrate, said first pattern of capacitive sensor traces comprised of a substantially transparent material;

disposing a second pattern of capacitive sensor traces above said substantially transparent substrate, said second pattern of capacitive sensor traces comprised of;

a conductive material for electrically coupling portions of said second pattern of capacitive sensor traces; and

said substantially transparent material, said substantially transparent material of said first pattern of capacitive sensor traces and said substantially transparent material of said second pattern of capacitive sensor traces disposed in a common layer above said substantially transparent substrate.

23. The method for providing said capacitive sensor as recited in claim 22, further comprising:

disposing an insulator to electrically insulate said first pattern of capacitive sensor traces and said conductive material.

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

disposing a substantially opaque insulator 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 23, wherein said disposing said insulator comprises:

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