PHYSICAL FORCE CAPACITIVE TOUCH SENSORS HAVING CONDUCTIVE PLANE AND BACKLIGHTING

• US 20120217147A1
• Filed: 05/10/2012
• Published: 08/30/2012
• Est. Priority Date: 10/27/2008
• Status: Active Grant

• Current Assignee: Microchip Technology Incorporated
• Original Assignee: Microchip Technology Incorporated
• Inventors: Porter, Stephen B., Curtis, Keith, Duvenhage, Fanie
• Granted Patent: US 8,858,003 B2
• Time in Patent Office: Days
• US Class Current: 200/600
• 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: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches
• CPC Class Codes: H03K 2217/960785 with illumination
• CPC Class Codes: H03K 2217/960795 using organic light emitting devices, e.g. light emitting polymer [OEP] or OLED
• CPC Class Codes: H03K 2217/9655 using a single or more light guides

Abstract

A physical force capacitive touch sensor comprises a capacitive sensor element on a substrate, a physically deformable electrically insulating spacer over the capacitive sensor element and a conductive plane over the physically deformable electrically insulating spacer. A protective fascia may be placed over the conductive plane provides an environmental seal for physical and weather protection, but is not essential to operation of the capacitive touch sensor. Back lighting is accomplished with a light transmissive layer having a suspended metal target proximate to the capacitive touch sensor plate. When the light transmissive layer and metal target are displaced toward the capacitive touch sensor plate the capacitance value of the capacitive touch sensor plate changes and that change is detected.

Claims

1. A physical force capacitive touch sensor, comprising:

a substrate;

a capacitive sensor element on a face of the substrate;

a light source;

a deformable spacer covering the capacitive sensor element, wherein the deformable spacer allows light from the light source to pass therethrough;

a substantially non-deformable spacer surrounding the capacitive sensor element and the deformable spacer; and

a electrically conductive plane covering the deformable spacer and the substantially non-deformable spacer, wherein the electrically conductive plane allows light from the light source to pass therethrough;

wherein when a mechanical force is applied to the electrically conductive plane biased toward the capacitive sensor element, the capacitive sensor element changes capacitance.

2. A user interface having a plurality of physical force capacitive touch sensors, said user interface comprising:

a substrate;

a plurality of capacitive sensor elements on a face of the substrate;

at least one light source;

deformable spacers covering the plurality of capacitive sensor elements, wherein the deformable spacers allow light from the at least one light source to pass therethrough;

a substantially non-deformable spacer surrounding the plurality of capacitive sensor elements and the deformable spacers; and

a electrically conductive plane covering the deformable spacers and the substantially non-deformable spacer, wherein the electrically conductive plane allows light from the at least one light source to pass therethrough;

wherein when a mechanical force is applied to the electrically conductive plane biased toward a one of the plurality of capacitive sensor elements, the one of the plurality of capacitive sensor elements changes capacitance.

3. A backlit capacitive touch sensor key, comprising:

a substrate;

a capacitive sensor plate on the substrate;

a light source;

a spacer layer on the substrate, wherein the spacer layer has an opening that surrounds the capacitive sensor plate and the light source;

a over-layer having at least one opening therein to allow light to pass therethrough from the light source, the over-layer is attached to the spacer layer and forms a light transmission cavity between the substrate and the over-layer;

an over-mold button attached to a side of the over-layer opposite the light transmission cavity, the over-mold button being light transmissive; and

a metal target attached on a face of the over-layer proximate to the capacitive sensor plate, wherein when the over-mold button and the metal target are biased toward the capacitive sensor plate, a capacitance value of the capacitive sensor plate changes.

4. The backlit capacitive touch sensor key according to claim 3, wherein the light source is at least one light emitting diode (LED).

5. The backlit capacitive touch sensor key according to claim 3, wherein the light source is an organic light emitting diode (OLED) layer.

6. The backlit capacitive touch sensor key according to claim 3, wherein the light source is an electroluminescence (EL) layer.

7. The backlit capacitive touch sensor key according to claim 3, wherein the over-layer is nonmetallic.

8. The backlit capacitive touch sensor key according to claim 3, wherein the substrate is a printed circuit board.

9. A backlit capacitive touch sensor key, comprising:

a substrate;

a capacitive sensor plate on the substrate;

a light source;

a spacer layer on the substrate, wherein the spacer layer has an opening that surrounds the capacitive sensor plate and the light source;

a flexible light translucent layer;

a metal target attached to a face of the flexible light translucent layer proximate to the capacitive sensor plate, wherein the metal target has opening therein to allow light to pass therethrough;

the flexible light translucent layer is attached to the spacer layer over the capacitive sensor plate and light source, wherein a light transmission cavity is formed between the substrate and the flexible light translucent layer and metal target;

whereby when the flexible light translucent layer and metal target are biased toward the capacitive sensor plate, a capacitance value of the capacitive sensor plate changes.

10. The backlit capacitive touch sensor key according to claim 9, wherein the light source is at least one light emitting diode (LED).

11. The backlit capacitive touch sensor key according to claim 9, wherein the light source is an organic light emitting diode (OLED) layer.

12. The backlit capacitive touch sensor key according to claim 9, wherein the light source is an electroluminescence (EL) layer.

13. The backlit capacitive touch sensor key according to claim 9, wherein the metal target is light opaque and has at least one opening therein for light from the light source to pass therethrough.

14. The backlit capacitive touch sensor key according to claim 9, further comprising a flexible over-layer over the flexible light translucent layer.

15. The backlit capacitive touch sensor key according to claim 14, wherein the flexible over-layer is made of light transmissive material.

16. The backlit capacitive touch sensor key according to claim 14, wherein the flexible over-layer is made of light opaque material and has opening therein for light from the light source to pass therethrough.

17. The backlit capacitive touch sensor key according to claim 16, wherein the flexible over-layer is metal.

18. The backlit capacitive touch sensor key according to claim 16, wherein the flexible over-layer is nonmetallic.

19. The backlit capacitive touch sensor key according to claim 9, wherein the substrate is a printed circuit board.

20. A backlit capacitive touch sensor key, comprising:

a substrate;

a capacitive sensor plate on the substrate;

a light source arranged to shine through the capacitive sensor plate;

an opaque layer on the substrate, wherein the opaque layer has an opening that surrounds the capacitive sensor plate;

a flexible light translucent layer attached to the opaque layer, the flexible light translucent layer is over the capacitive sensor plate, wherein a light transmission cavity is formed between the substrate and the flexible light translucent layer; and

an electrically conductive and light translucent coating on a face of the flexible light translucent layer proximate to the capacitive sensor plate, wherein when the flexible light translucent layer is biased toward the capacitive sensor plate, a capacitance value of the capacitive sensor plate changes.

21. The backlit capacitive touch sensor key according to claim 20, wherein the light source is at least one light emitting diode (LED).

22. The backlit capacitive touch sensor key according to claim 20, wherein the light source is an organic light emitting diode (OLED) layer.

23. The backlit capacitive touch sensor key according to claim 20, wherein the light source is an electroluminescence (EL) layer.

24. The backlit capacitive touch sensor key according to claim 20, wherein the electrically conductive and light translucent coating is indium tin oxide (ITO).

25. The backlit capacitive touch sensor key according to claim 20, wherein the electrically conductive and light translucent coating is antimony tin oxide (ATO).

26. The backlit capacitive touch sensor key according to claim 20, wherein the electrically conductive and light translucent coating is graphene.

27. The backlit capacitive touch sensor key according to claim 20, wherein the substrate is a printed circuit board.

28. The backlit capacitive touch sensor key according to claim 20, wherein the substrate is light translucent.

29. The backlit capacitive touch sensor key according to claim 28, wherein the light translucent substrate comprises glass.

30. The backlit capacitive touch sensor key according to claim 28, wherein the light translucent substrate comprises plastic.

31. The backlit capacitive touch sensor key according to claim 28, wherein the capacitive sensor plate comprises an electrically conductive and light translucent coating on a face of the light translucent substrate.

32. The backlit capacitive touch sensor key according to claim 31, wherein the electrically conductive and light translucent coating on the face of the light translucent substrate is selected from the group consisting of indium tin oxide (ITO), antimony tin oxide (ATO) and graphene.