Force-sensing capacitor elements, deformable membranes and electronic devices fabricated therefrom

• US 9,946,424 B2
• Filed: 10/14/2015
• Issued: 04/17/2018
• Est. Priority Date: 11/05/2014
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Frey, Matthew H.
• Primary Examiner(s): McLoone, Peter D
• Application Number:
  US15/518,301
• Publication Number:
  US 20170308204A1
• Time in Patent Office: 916 Days
• CPC Class Codes: G01L 1/142 using capacitors
• 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
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

The present disclosure relates to deformable membranes and force-sensing capacitor elements useful, for example, in electronic devices that include, for example touch screen displays or other touch sensors. The deformable membranes, generally, include a first, second and third layers, with a first arrangement of a plurality of first structures interposed between the first and third layers and a second arrangement of a plurality of second structures interposed between the second and third layers. At least a portion, but not all, of the plurality of first structures have first and/or second surfaces that each overlap through the thickness of the deformable membrane with one or more of the first surfaces or with one or more of the second surfaces of the plurality of second structures. Electrodes or one or more electrode pairs are incorporated into the deformable membrane layer(s) to form force-sensing capacitors. The present disclosure also relates to methods of making deformable membranes and force-sensing capacitor elements, and electronic devices, e.g. touch screen displays that include the deformable membranes and force-sensing capacitor elements.

Claims

1. A deformable membrane comprising:

a first layer having first and second major surfaces;

a second layer having first and second major surfaces;

a third layer having first and second major surfaces interposed between the second major surface of the first layer and the second major surface of the second layer;

a first arrangement comprising a plurality of first structures, with corresponding first void regions, interposed between the second major surface of the first layer and the first major surface of the third layer, wherein each first structure has a first surface facing the second major surface of the first layer and a second surface facing the first major surface of the third layer; and

a second arrangement comprising a plurality of second structures, with corresponding second void regions, interposed between the second major surface of the second layer and the second major surface of the third layer, wherein each second structure has a first surface facing the second major surface of the second layer and a second surface facing the second major surface of the third layer; and

wherein

i) from about 1% to about 99% of the plurality of first structures have first surfaces that each overlap through the thickness of the deformable membrane with one or more of the first surfaces or with one or more of the second surfaces of the plurality of second structures, or

ii) from about 1% to about 99% of the plurality of first structures have second surfaces that each overlap through the thickness of the deformable membrane with one or more of the first surfaces or with one or more of the second surfaces of the plurality of second structures,

wherein the first structures of the first arrangement are arranged according to a first array comprising a series of repeating lattice of positions,

wherein the second structures of the second arrangement are arranged according to a second array comprising a series of repeating lattice of positions, and

wherein the first repeating lattice of positions and the second repeating lattice of positions differ by a non-zero bias angle.

2. A deformable membrane according to claim 1, wherein at least one of the first and second fill factors of the first structures is between about 1 percent and about 60 percent and at least one of the first and second fill factors of the second structures is between about 1 percent and about 60 percent.

3. A deformable membrane according to claim 1, wherein the third layer comprises a material selected from the group of poly(ethyleneterephthalate), poly(ethylenenaphthalate), aramid polymer, polyether ether ketone, polyether sulfone, fluoropolymer, acrylic polymer, polyimide, glass, silicone, neoprene rubber, isoprene rubber, (ethylene propylene diene monomer) rubber, polyurethane, or epoxy.

4. A deformable membrane according to claim 1, wherein the first structures or the second structures comprise acrylic polymer, silicone, neoprene rubber, isoprene rubber, (ethylene propylene diene monomer) rubber, polyurethane, fluoropolymer, or epoxy.

5. A deformable membrane according to claim 1, wherein the third layer has a thickness of between about 5 micrometers and about 250 micrometers.

6. A deformable membrane according to claim 1, wherein the height of the first structures and the height of the second structures are between about 5 micrometers and about 1 millimeter.

7. A deformable membrane according to claim 1, wherein the average width of the plurality of first structures and the average width of the plurality of second structures are between about 5 micrometers and about 5 millimeters.

8. A deformable membrane according to claim 1, wherein the average width of the plurality of first structures is approximately equal to the average width of the plurality of second structures.

9. A deformable membrane according to claim 1, wherein the average width of the plurality of first structures is at least 25 percent larger than the average width of the plurality of second structures.

10. A deformable membrane according to claim 1, wherein average distance between nearest neighboring first structures and the average distance between nearest neighboring second structures are between approximately 20 micrometers and 20 millimeters.

11. A deformable membrane according to claim 1, wherein the bias angle is between about 10 degrees and 80 degrees.

12. A deformable membrane according to claim 1, wherein the volumetric shape of the first structures and the volumetric shape of the second structures are selected from at least one of cylinders, elliptical pillars, pyramids, truncated pyramids, parallelepipeds, domes, truncated domes, spheres, truncated spheres, ellipsoids, truncated ellipsoids, prisms, and wedges.

13. A force-sensing capacitor element comprising:

a deformable membrane according to claim 1;

at least one first electrode embedded within the first layer or proximate to or in contact with one of the first major surface and the second major surface of the first layer; and

at least one second electrode embedded within the second layer or proximate to or in contact with one of the first major surface and the second major surface of the second layer.

14. A force-sensing capacitor according to claim 13, wherein the at least one first electrode includes a plurality of first electrodes.

15. A force-sensing capacitor according to claim 13, wherein the at least one second electrode includes a plurality of second electrodes.

16. A force-sensing capacitor element comprising:

a deformable membrane according to claim 1; and

at least one first electrode and at least one second electrode forming at least one electrode pair embedded within the first layer or proximate to or in contact with at least one of the first and the second major surfaces of the first layer, wherein each of the at least one first electrode and the at least one second electrode are separated by a gap.

17. A deformable membrane comprising:

a first layer having first and second major surfaces;

a second layer having first and second major surfaces;

a third layer having first and second major surfaces interposed between the second major surface of the first layer and the second major surface of the second layer;

a first arrangement comprising a plurality of first structures, with corresponding first void regions, interposed between the second major surface of the first layer and the first major surface of the third layer, wherein each first structure has a first surface facing the second major surface of the first layer and a second surface facing the first major surface of the third layer; and

a second arrangement comprising a plurality of second structures, with corresponding second void regions, interposed between the second major surface of the second layer and the second major surface of the third layer, wherein each second structure has a first surface facing the second major surface of the second layer and a second surface facing the second major surface of the third layer; and

wherein

i) from about 1% to about 99% of the plurality of first structures have first surfaces that each overlap through the thickness of the deformable membrane with one or more of the first surfaces or with one or more of the second surfaces of the plurality of second structures, or

ii) from about 1% to about 99% of the plurality of first structures have second surfaces that each overlap through the thickness of the deformable membrane with one or more of the first surfaces or with one or more of the second surfaces of the plurality of second structures,

wherein at least one of the first structures of the first arrangement and the second structures of the second arrangement are arranged according to at least a partially random positional arrangement of structures.