CAPACITIVE TOUCHPAD

• US 20120256876A1
• Filed: 04/06/2012
• Published: 10/11/2012
• Est. Priority Date: 04/11/2011
• Status: Abandoned Application

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Elan Microelectronics Corporation
• Inventors: YEH, I-HAU, HSU, TA-FAN, HUANG, SHU-WEI
• Application Number:
  US13/441,075
• Publication Number:
  US 20120256876A1
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 capacitive touchpad has insulating blocks provided above and below a resilient layer. The insulating blocks above the resilient layer are offset in position with respect to the insulating blocks below the resilient layer. Due to the insulating blocks, a plurality of gaps are formed in the capacitive touchpad. The gaps are filled with a fluid medium. When a conductive or non-conductive object touches the capacitive touchpad, the resilient layer is deformed at the touched position and thereby displaces the fluid medium completely from the affected gaps. As a result, the distance and the dielectric coefficient between the resilient layer or an electrode plate and a sensor layer are changed, causing variation in capacitance.

Claims

1. A capacitive touchpad, comprising:

a protective layer;

a resilient conductive layer provided below the protective layer;

a sensor layer provided below the resilient conductive layer, the sensor layer having an upper surface provided with an insulating layer;

a plurality of first insulating blocks provided between the protective layer and the resilient conductive layer; and

a plurality of second insulating blocks provided between the resilient conductive layer and the sensor layer and offset in position with respect to the first insulating blocks;

wherein the sensor layer and the resilient conductive layer form a capacitor.

2. The capacitive touchpad of claim 1, wherein the resilient conductive layer comprises a conductive poly styrene film or a conductive indium tin oxide (ITO) film.

3. The capacitive touchpad of claim 1, wherein the first and the second insulating blocks are formed by ink printing in multiple layers, applying a double-sided adhesive tape, etching, or non-conductive vacuum metallization.

4. The capacitive touchpad of claim 1, wherein the sensor layer is a printed circuit board.

5. The capacitive touchpad of claim 1, wherein a first driving signal is applied to the sensor layer during detection of the capacitor.

6. The capacitive touchpad of claim 5, wherein a second driving signal in anti-phase with the first driving signal or a ground potential is applied to the resilient conductive layer during detection of the capacitor.

7. A capacitive touchpad, comprising:

a protective layer having a lower surface formed as a conductive electrode plate;

a resilient insulating layer provided below the protective layer;

a sensor layer provided below the resilient insulating layer ;

a plurality of first insulating blocks provided between the protective layer and the resilient insulating layer; and

a plurality of second insulating blocks provided between the resilient insulating layer and the sensor layer and offset in position with respect to the first insulating blocks;

wherein the sensor layer and the conductive electrode plate form a capacitor.

8. The capacitive touchpad of claim 7, wherein the resilient insulating layer comprises poly ethylene terephthalate, FR4, polyimide, Mylar, poly carbonate, or ethylene-vinyl acetate copolymer.

9. The capacitive touchpad of claim 7, wherein the first and the second insulating blocks are formed by ink printing in multiple layers, applying a double-sided adhesive tape, etching, or non-conductive vacuum metallization.

10. The capacitive touchpad of claim 7, wherein the sensor layer is a printed circuit board.

11. The capacitive touchpad of claim 7, wherein a first driving signal is applied to the sensor layer during detection of the capacitor.

12. The capacitive touchpad of claim 11, wherein a second driving signal in anti-phase with the first driving signal or a ground potential is applied to the conductive electrode plate during detection of the capacitor.

13. A capacitive touchpad, comprising:

a flexible sensor layer having an upper surface provided with a protective film and a lower surface provided with an insulating film;

a resilient conductive layer provided below the flexible sensor layer;

a bottom plate provided below the resilient conductive layer;

a plurality of first insulating blocks provided between the flexible sensor layer and the resilient conducive layer; and

a plurality of second insulating blocks provided between the resilient conductive layer and the bottom plate and offset in position with respect to the first insulating blocks;

wherein the flexible sensor layer and the resilient conductive layer form a capacitor.

14. The capacitive touchpad of claim 13, wherein the resilient conductive layer comprises a conductive poly styrene film or a conductive indium tin oxide (ITO) film.

15. The capacitive touchpad of claim 13, wherein the first and the second insulating blocks are formed by ink printing in multiple layers, applying a double-sided adhesive tape, etching, or non-conductive vacuum metallization.

16. The capacitive touchpad of claim 13, wherein a first driving signal is applied to the flexible sensor layer during detection of the capacitor.

17. The capacitive touchpad of claim 16, wherein a second driving signal in anti-phase with the first driving signal or a ground potential is applied to the resilient conductive layer during detection of the capacitor.

18. A capacitive touchpad, comprising:

a flexible sensor layer having an upper surface provided with a protective film;

a resilient insulating layer provided below the flexible sensor layer;

a conductive layer provided below the resilient insulating layer;

a plurality of first insulating blocks provided between the flexible sensor layer and the resilient insulating layer; and

a plurality of second insulating blocks provided between the resilient insulating layer and the conductive layer and offset in position with respect to the first insulating blocks;

wherein the flexible sensor layer and the conductive layer form a capacitor.

19. The capacitive touchpad of claim 18, wherein the resilient insulating layer comprises poly ethylene terephthalate, FR4, polyimide, Mylar, poly carbonate, or ethylene-vinyl acetate copolymer.

20. The capacitive touchpad of claim 18, wherein the first and the second insulating blocks are formed by ink printing in multiple layers, applying a double-sided adhesive tape, etching, or non-conductive vacuum metallization.

21. The capacitive touchpad of claim 18, wherein a first driving signal is applied to the flexible sensor layer during detection of the capacitor.

22. The capacitive touchpad of claim 21, wherein a second driving signal in anti-phase with the first driving signal or a ground potential is applied to the conductive layer during detection of the capacitor.