Patent Application
20180032181
Force-sensing capacitor elements have been contemplated or applied for many years in touch displays, keyboards, touch pads, and other electronic devices. The recent renaissance of the touch user interface (paradigm shift from resistive to projected capacitive) has catalyzed a renewed interest among electronic device makers to consider force-sensing. The main challenges associated with the integration of force-sensing with the display of an electronic device, for example, include linearity of response, speed of response and speed of recovery, preservation of device mechanical robustness, preservation of device hermiticity where desired, thinness of construction, sensitivity, determination of position or positions of force application, and noise rejection. The capacitors of the present disclosure have advantages in the areas, for example, of response speed and recovery speed, linearity of response, thinness, and determination of touch position.
The present disclosure relates to force-sensing capacitor elements useful, for example, in electronic devices that include, for example touch screen displays or other touch sensors. The present disclosure also relates to deformable membranes useful in the fabrication of the force-sensing capacitor elements. Force-sensing (and also force-measuring) capacitor elements are provided with electrodes and deformable membranes (e.g., insulators) having specific design features. The capacitor elements can be integrated within a display or electronic device, for example, to detect and measure the magnitude and/or direction of force or pressure applied to the display or electronic device. The capacitor elements can be integrated, for example, at the periphery of or beneath a display, to sense or measure force applied to the display. Alternatively, the capacitor elements can be integrated within a touch pad, keyboard, or digitizer (e.g., stylus input device), for example.
In one aspect, the present disclosure provides a force-sensing capacitor element comprising:
In another aspect, the present disclosure provides a force-sensing capacitor element comprising:
In another aspect, the present disclosure provides a force-sensing capacitor element comprising:
In another aspect, the present disclosure provides a force-sensing capacitor element comprising:
In another aspect, the present disclosure provides a force-sensing capacitor element comprising:
In yet another aspect, the present disclosure provides a deformable membrane for a force-sensing capacitor element comprising:
In another aspect, the present disclosure provides a deformable membrane for a force-sensing capacitor element comprising:
In yet another aspect, the present disclosure provides an electronic device comprising a force-sensing capacitor element.
In still another aspect, the present disclosure provides a touch screen display comprising a force-sensing capacitor element.
Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. As used herein, the word “between”, as applied to numerical ranges, includes the endpoints of the ranges, unless otherwise specified. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. The figures may not be drawn to scale.
All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.
Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein.
The recitation of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range.
As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the context clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the context clearly dictates otherwise.
An embodiment of a deformable membrane, according to the present disclosure includes 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 or in contact with the second major surface of the first layer and a second surface facing or in contact with the first major surface of the third layer; and a second arrangement comprising one or more 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 of the one or more second structures has a first surface facing or in contact with the second major surface of the second layer and a second surface facing or in contact with the second major surface of the third layer; and wherein each first surface of the first structures and each first surface of the one or more second structures are offset from one another such that there is no overlap between each first surface of the first structures and each first surface of the one or more second structures, through the thickness of the deformable membrane. Throughout this disclosure, if one surface is in contact with another surface, the two surfaces are, inherently, facing each other. Several specific, but non-limiting, embodiments are shown in
It is within the scope of the present disclosure, within deformable membranes or force-sensing capacitors comprising first structures and second structures wherein each first surface of the first structures and each first surface of the one or more second structures are offset from one another such that there is no overlap between each first surface of the first structures and each first surface of the one or more second structures, for there to be present a small proportion of first structures that are not offset from second structures, for example as might arise from defects in manufacturing.
Referring now to
Deformable membrane 100 may include, optionally, a plurality of third structures 162, having a first surface 162a proximate to or in contact with the second major surface 130b of the third layer 130 and imaginary axes, Z3, running perpendicular to and through the center of the centroid of first surfaces 162a. Throughout this disclosure, if a third structure is said to be proximate to a major surface of a layer, the third structure may be in contact with the major surface of the layer or one or more additional layers may be interposed between the third structure and major surface of the layer, with the third structure in contact with the surface of the adjacent additional layer. Third structures 162 are located in the void regions 154 of the second arrangement 150. In some embodiments, each third structure 162 aligns and overlaps, through the thickness of the deformable membrane 100, with a corresponding first structure 142 of the first arrangement 140.
First layer 110, second layer 120 and third layer 130 may be fabricated from materials having a Young's modulus over a broad range. First layer 110, second layer 120 and third layer 130 may have a Young's modulus between, for example, about 0.1 MPa and about 100 GPa. The selection of the Young's modulus of each layer is based on the end-use application requirements for the deformable membrane 100 which will subsequently dictate the design criteria for the deformable membrane 100. In some embodiments, the Young's modulus of one or more of first layer 110, second layer 120 and third layer 130 may be required to be relatively high, providing a relatively stiff layer (e.g., a glass layer with Young's modulus of between about 50 GPa and about 100 GPa). In these embodiments, the Young's modulus of one or more of first layer 110, second layer 120 and third layer 130 may be greater than about 0.05 GPa, greater than about 0.1 GPa or even greater than about 1 GPa; less than about 100 GPa, less than about 10 GPa or even less than about 5 GPa. The Young's modulus may be between about 0.05 GPa and about 10 GPa, between about 0.1 GPa and about 10 GPa, between about 1 GPa and 10 GPa or even between about 1 GPa and about 5 GPa. In other embodiments, the Young's modulus of one or more of first layer 110, second layer 120 and third layer 130 may be required to be relatively low, providing a relatively flexible layer (e.g., an elastomer, for example a silicone elastomer, with Young's modulus of between 0.5 and 5 MPa). In these embodiments, the Young's modulus of one or more of first layer 110, second layer 120 and third layer 130 may be greater than about 0.1 MPa, greater than about 1.0 MPa, greater than about 2.0 MPa, greater than about 5.0 MPa or even greater than about 10 MPa; less than about 50 MPa, less than about 40 MPa or even less than about 30 MPa. The Young's modulus may be between about 0.1 MPa and about 0.05 GPa, between about 1 MPa and about 40 MPa, between about 2 MPa and about 30 MPa or even between about 3 MPa and about 25 MPa. In some embodiments, the Young's modulus of the third layer is less than at least one of the Young's modulus of the first layer and second layer.
First layer 110, second layer 120 and third layer 130 may be dielectric materials, e.g. may include ceramic and polymeric materials (thermoplastics, thermoplastic elastomers and thermosets, including glassy thermosets and elastomeric thermosets, i.e. rubbers, and foams, including foamed rubbers). Suitable ceramic materials include, but are not limited to, glass, titanium dioxide, barium titanate, tantalum pentoxide, sapphire and the like. Suitable polymeric materials include, but are not limited to, polyesters (e.g. polyethylene terephtahlate and polyethylene naphthalate), polycarbonates, polyimides, polyamides (e.g. Nylon 6,6), polyalkylenes (e.g. polyethylene and polypropylene), polyether sulphones, polyether ether ketones (PEEKs), polyarylene ether nitriles (PENs), polyacrylates (e.g. acrylics), polystyrene, fluoropolymers (e.g. fluoroplastics and fluoroelastomers), and rubbers (e.g. silicone, EPDM, neoprene, isoprene, natural rubber and the like). Two or more of first layer 110, second layer 120 and third layer 130 may include the same material, i.e. may be fabricated from the same material. In some embodiments all three layers include the same material. In other embodiments, each of the first layer, the second layer and the third layer may be different materials. Each of first layer 110, second layer 120 and third layer 130 may include multiple materials in the form of a blend or composite of materials or a laminate. A laminate is defined as two or more sheets of material coupled together to form a single structure. In some embodiments, one or more of first layer 110, second layer 120 and third layer 130 are not laminates.
In some embodiments of the force-sensing capacitors, one or more of the first layer 110, the second layer 120, and the third layer 130 are metals (also referred to herein as being metallic), for example composed of metal (metallic material). For example, in some embodiments the first layer and the second layer are metals. In other embodiments, the second layer and the third layer are metals. In yet other embodiments, the first layer, the second layer, and the third layer are metals. Examples of useful metals include elemental metals, metal alloys, and intermetallics, including but not limited to copper, silver, stainless steel, spring steel, tool steel, brass, nickel, aluminum, titanium, nickel titanium alloy (e.g., Nitinol). In the present disclosure a layer that is described to be a metal may comprise regions (e.g., layers) of different metals (i.e., different metal compositions).
First structures 142 and one or more second structures 152 have heights, h1 and h2, respectively. The deformable membranes of the present disclosure are not particularly limited with respect to heights, h1 and h2, although some heights, h1 and h2, may be particularly advantageous. The heights h1 and h2 may each be greater than about 5 microns, greater than about 10 microns, greater than about 20 microns, greater than about 30 microns, greater than about 40 microns, greater than about 50 microns, greater than about 100 microns, greater than about 250 microns, greater than about 500 microns; less than about 1 millimeter, less than about 500 microns, less than about 250 microns, less than about 175 microns, or even less than 150 microns. Each of the heights h1 and h2 may be between about 5 microns and about 1 mm, between about 10 microns and about 500 microns between about 15 microns and about 250 microns, between about 25 microns and about 150 microns, between about 40 microns and about 125 microns, between about 45 microns and about 110 microns or even between about 50 microns and about 100 microns. The heights h1, of first structures 142 may all be the same, within the normal tolerances of their manufacturing process. In these embodiments, first layer 110 and third layer 130 are substantially parallel to one another. The heights h1, may vary, with the heights h1 of each individual first structure 142 being within about 30%, about 20%, about 10% or even about 5% of the average value of all heights h1. In embodiments where the heights, h1 taper systematically across an area of the deformable membrane, the variation in heights h1 may cause a variation in the distance between first layer 110 and third layer 130 and the two layers may not be substantially parallel to one another, and first layer 110 and second layer 120 may also not be substantially parallel to one another. The heights h2, of one or more second structures 152 may all be the same, within the normal tolerances of their manufacturing process. In these embodiments, second layer 120 and third layer 130 are substantially parallel to one another. The heights h2, may vary, with the heights h2 of each individual second structure 152 being within about 30%, about 20%, about 10% or even about 5% of the average value of all heights h2. In embodiments where the heights, h2 taper systematically across an area of the deformable membrane, the variation in heights h2 may cause a variation in the distance between second layer 120 and third layer 130 and the two layers may not be substantially parallel to one another, and second layer 120 and first layer 110 may also not be substantially parallel to one another. In some embodiments, first layer 110, second layer 120 and third layer 130 may be substantially parallel to one another. First layer 110 may be substantially parallel to second layer 120. First layer 100 may be substantially parallel to third layer 130. Second layer 120 may be substantially parallel to third layer 130.
First structures 142 have a widths w1. The deformable membranes of the present disclosure are not particularly limited with respect to widths w1, although some widths w1 may be particularly advantageous. The widths w1 may be greater than about 5 microns, greater than about 10 microns, greater than about 20 microns, greater than about 30 microns, greater than about 40 microns or even greater than about 50 microns; less than about 5 mm, less than about 1 mm, less than about 0.5 mm, or even less than about 0.25 mm. The widths w1 may be between about 5 microns and about 5 mm, between about 10 microns and about 1 mm, between about 10 microns and about 1 mm, between about 20 microns and about 0.5 mm, between about 30 microns and about 0.25 mm or even between about 40 microns and about 200 microns. The widths w1 of first structures 142 may all be the same, within the normal tolerances of their manufacturing process, or may vary within the size range described above. One or more second structures 152 have a widths w2. The widths w2 may be greater than about 5 microns, greater than about 10 microns, greater than about 20 microns, greater than about 30 microns, greater than about 40 microns or even greater than about 50 microns; less than about 10 mm, less than about 5 mm, less than about 1 mm, less than about 0.5 mm, or even less than about 0.25 mm. The widths w2 may be between about 5 microns and 10 mm, between about 10 microns and about 1 mm, between about 20 microns and about 0.5 mm, between about 30 microns and about 0.25 mm or even between about 40 microns and about 200 microns. The widths w2 of one or more second structures 152 may all be the same, within the normal tolerances of their manufacturing process, or may vary within the size range described above. Second void regions 154 have widths w4. The widths w4 may be greater than about 20 microns, greater than about 50 microns, greater than about 100 microns, greater than about 200 microns, greater than about 300 microns or even greater than about 400 microns; less than about 20 mm, less than about 15 mm, less than about 10 mm, less than about 5 mm, or even less than about 1 mm. The widths w4 may be between about 20 microns and about 20 mm, between about 10 microns and about 1 mm, between about 20 microns and about 0.5 mm, between about 30 microns and about 0.25 mm or even between about 40 microns and about 200 microns. The widths w4 may all be the same, within the normal tolerances of their manufacturing process, or may vary within the size range described above.
The lengths, L1, of first structures 142 and the lengths, L2, of one or more second structures 152 (neither shown in
At least some of first structures 142 of first arrangement 140 and at least some of one or more second structures 152 of second arrangement 150 may be isolated discrete structures, i.e. no portion of an individual structure is connected to another portion of a different individual structure as shown in
The number of first structures 142 of first arrangement 140 and one or more second structures 152 of second arrangement 150 are not particularly limited and may be selected based on the end use requirements. As the deformable membranes may be used in force-sensing capacitor elements, useful in, for example a touch screen display, the resolution requirements of the touch screen display may dictate the resolution requirements of the force-sensing capacitor element and subsequently the design, e.g. number of first and second structures, the pattern of first and second structures and the size of the first and second structures. The areal density of first structures 142 and one or more second structures 152 may each be greater than about 0.04 structures/cm2, greater than about 1 structures/cm2, greater than about 10 structures/cm2, greater than about 100 structures/cm2 or even greater than about 1,000/cm2 structures; less than about 1,000,000 structures/cm2, less than about 500,000 structures/cm2, less than about 100,000 structures/cm2, less than about 50,000 structures/cm2 or even less than about 10,000 structures/cm2.
Referring back to
The shape of first structures 142 and one or more second structures 152 are not particularly limited. The shape of first structures 142 and second structures 152 include, but are not limited to, cubic, cylindrical, prismatic, rectangular, hexagonal, octagonal, pyramidal, truncated pyramidal, conical, truncated conical, ellipsoidal, spheroidal, hemispherical and combinations thereof. The shape of first structures 142 and one or more second structures 152 may be parallelepiped, e.g. rectangular parallelpiped. First surface 142a and second surface 142b of first structures 142 and first surface 152a and second surface 152b of one or more second structures 152 may have shapes that include, but are not limited to, flat, pointed, faceted and rounded.
First structures 142 and one or more second structures 152 may be dielectric materials, e.g. ceramic and polymeric materials (thermoplastics, thermoplastic elastomers and thermosets, including glassy thermosets and elastomeric thermosets, i.e rubbers). Suitable ceramic materials and polymeric materials include, but are not limited to, those described for first layer 110, second layer 120 and third layer 130.
First structures 142 and second structures 152 may be fabricated from materials having a Young's modulus over a broad range. First structures 142 and second structures 152 may have a Young's modulus between about 0.1 MPa and about 10 GPa. The selection of the Young's modulus of first structures 142 and second structures 152 is based on the end-use application requirements for the deformable membrane 100 which will subsequently dictate the design criteria for the deformable membrane 100. In some embodiments, the Young's modulus of one or more of first structures 142 and second structures 152 may be required to be relatively high, providing a relatively stiff layer. In these embodiments, the Young's modulus of one or more of first structures 142 and second structures 152 may be greater than about 0.05 GPa, greater than about 0.1 GPa or even greater than about 1 GPa; less than about 10 GPa, less than about 7.5 GPa or even less than about 5 GPa. The Young's modulus may be between about 0.05 GPa and about 10 GPa, between about 0.1 GPa and about 10 GPa, between about 1 GPa and 10 GPa or even between about 1 GPa and about 5 GPa. In other embodiments, the Young's modulus of one or more of first structures 142 and second structures 152 may be required to be relatively low, providing a relatively flexible layer. In these embodiments, the Young's modulus of one or more of first structures 142 and second structures 152 may be greater than about 0.1 MPa, greater than about 1.0 MPa, greater than about 2.0 MPa, greater than about 5.0 MPa or even greater than about 10 MPa; less than about 50 MPa, less than about 40 MPa or even less than about 30 MPa. The Young's modulus may be between about 0.1 MPa and about 0.05 GPa, between about 1 MPa and about 40 MPa, between about 2 MPa and about 30 MPa or even between about 5 MPa and about 25 MPa. In some embodiments, the Young's modulus of the first structures 142, the second structures 152 and the third layer 130 are the same and first structures 142, second structures 152 and the third layer 130 are a unitary body, formed by, for example, injection molding of a polymer.
First arrangement 140 and second arrangement 150 may include various patterns of first structures 142 and one or more second structures 152, respectively. The patterns are not particularly limited and may include a random pattern of the structures, a non-random pattern of the structures and combinations thereof. The patterns may be linear, e.g. a line of first structures and a line of one or more second structure, or may be two-dimensional, e.g. a two-dimensional array of first structures and a two-dimensional array of one or more second structures. In some embodiments, at least one of first arrangement 140 and second arrangement 150 include a pattern of first structures 142 and one or more second structures 152, respectively, that include but are not limited to, square grid array pattern, rectangular grid array pattern, hexagonal grid array pattern, a set of parallel lines, a set of curved parallel lines, two sets of parallel lines, wherein one first set of parallel lines cross the second set of parallel lines at an included angle theta, wherein the smallest included angle, theta, between the first set of parallel lines and the second set of parallel lines may be between about 5° and about 90°, between about 30° and about 90° or even between about 50° and about 90°. Combinations of patterns may be used in different areas of each arrangement. First arrangement 140 and second arrangement 150 may include the same pattern or differing patterns. Second arrangement 150 may include only one structure 152 that includes at least two or more second void regions 154. At least some of the second void regions 154 will align, through the thickness of the deformable membrane, to the position of first structures 142. In some embodiments, one or both of first arrangement 140 and second arrangement 150 include void regions 144 and second void region 154, respectively, that enables a fluid, i.e. a gas or liquid, to flow out from any area of respective first arrangement 140 and second arrangement 150.
In some embodiments, the size and shape of first structures 142 and one or more second structures 152, as well as, the patterns of the structures of arrangements 140 and 150 are selected, such that, each first surface 142a of the first structures 142 and each first surface 152a of one or more second structures 152 are offset from one another such that there is no overlap between each first surface 142a of the first structures 142 and each first surface 152a of the one or more second structures 150, through the thickness of the deformable membrane.
Optional third structures 162 have widths w3. The deformable membranes of the present disclosure are not particularly limited with respect to the widths w3, although some widths w3 may be particularly advantageous. The widths w3 may be greater than about 5 microns, greater than about 10 microns, greater than about 20 microns, greater than about 30 microns, greater than about 40 microns or even greater than about 50 microns; less than about 5 mm, less than about 3, less than about 1 mm, less than about 0.5 mm, or even less than 0.25 mm. The widths w3 may be between about 5 microns and about 5 mm, between about 10 microns and about 3 mm, between about 20 microns and 1 mm, between about 30 microns and 0.5 mm or even between about 40 microns and 25 mm. The widths w3 of third structures 162 may all be the same, within the normal tolerances of their manufacturing process, or may vary within the size range described above. Third structures 162 have heights h3. The deformable membranes of the present disclosure are not particularly limited with respect to the heights h3, although some heights h3 may be particularly advantageous. The heights h3 may be greater than about 5 microns, greater than 10 microns, greater than 20 microns, greater than 30 microns, greater than 40 microns or even greater than 50 microns; less than about 240, less than about 225 microns, less than about 200 microns, less than about 175 microns, or even less than 150 microns. The heights h3 may be between about 5 microns and about 240 microns, between about 10 microns and about 200 microns, between about 15 microns and about 175 microns, between about 25 microns and about 150 microns, between about 40 microns and about 125 microns, between about 45 microns and about 110 microns or even between about 50 microns and about 100 microns. Heights h3 of third structures 162 may all be the same, within the normal tolerances of their manufacturing process. Heights h3 may vary, with the heights h3 of each individual first structure 162 being within about 20%, about 10% or even about 5% of the average value of all heights h3. The lengths of third structures 162, L3, (not shown in
The number of third structures 162 of first arrangement 160 in deformable membrane 100 is not particularly limited and may be selected based on the end use requirements. The number of third structures 162 may be the same or less than the number of first structures 142 of first arrangement 140. The areal density of third structures 162 may be greater than about 0.04 structures/cm2, greater than about 1 structures/cm2, greater than about 10 structures/cm2, greater than about 100 structures/cm2 or even greater than about 1,000/cm2 structures; less than about 1,000,000 structures/cm2, less than about 500,000 structures/cm2, less than about 100,000 structures/cm2, less than about 50,000 structures/cm2 or even less than about 10,000 structures/cm2.
In some embodiments, at least one of the dimensions w3, h3 and L3 of at least some of third structures 162 is less than the corresponding dimensions, w1, h1 and L1, of corresponding first structures 142. In other embodiments, all three dimensions w3, h3 and L3 of at least some of third structures 162 are less than the corresponding dimensions w1, h1 and L1 of corresponding first structures 142. In some embodiments, at least some of heights h3 of third structures 162 are less than heights h2 of adjacent second structures 152 and the distal end of third structure 162 does not contact second surface 120b of second layer 120. The shape of third structures 162 and the shape of their surfaces are not particularly limited and include, but are not limited to, the shapes described for first structures 142 and one or more second structures 152. The patterns of third structures 162 are not particularly limited and include, but are not limited to, the patterns described for first structures 142 and one or more second structures 152.
The third structures may be dielectric materials, e.g. ceramic and polymeric materials and may include the same ceramic and polymeric materials described for the first, second and third layers. The third structures may include electrically conductive materials. The third structures may be composites, e.g. a polymer matrix composite including a polymeric matrix and, at least one of, electrically conductive particles, fibers, woven or non-woven mats and the like. The electrically conductive particles, fibers, woven or non-woven mats and the like may include metals, including but are not limited to, aluminum, copper, silver and gold. They also may be non-electrically conductive particles, fibers, woven or non-woven mats that have been coated with a conductive material, e.g. a metal, including but not limited to, aluminum, copper, silver and gold.
During use, in for example, a force-sensing capacitor element, a force F is applied to the first major surface 110a of first layer 110 of deformable membrane 100,
Another embodiment of a deformable membrane, according to the present disclosure, is shown in
Yet another embodiment of a deformable membrane, according to the present disclosure, is shown in
In some embodiments of deformable membranes of the present disclosure, the first structures of the first arrangement have corresponding imaginary axes, Z1, aligned perpendicular to and running through the centroids of their first surfaces, at least one of the imaginary axes Z1, at least about 25% of the imaginary axes Z1, at least about 50% of the imaginary axes Z1, at least about 75% of the imaginary axes Z1, at least about 90% of the imaginary axes Z1 or even all the imaginary axes Z1, of the first structures of the first arrangement is surrounded by the one or more second structures of the second arrangement such that an imaginary circle C1 in a region of the second arrangement, having a radius R drawn around the at least one of the imaginary axes, intersects the at least one or more second structures of the second arrangement along at least about 50% of the circumference length, along at least about 55% of the circumference length, along at least about 60% of the circumference length, along at least about 65% of the circumference length, along at least about 70% of the circumference length, along at least about 75% of the circumference length, along at least about 80% of the circumference length, along at least about 85% of the circumference length, along at least about 90% of the circumference length, along at least about 95% of the circumference length, or even 100% of the circumference length.
Yet another embodiment of a deformable membrane, according to the present disclosure, is shown in
In some embodiments of deformable membranes of the present disclosure, the first structures of the first arrangement have corresponding imaginary axes aligned perpendicular to and running through the centroids of their first surfaces, at least one of the imaginary axes Z1, at least about 25% of the imaginary axes Z1, at least about 50% of the imaginary axes Z1, at least about 75% of the imaginary axes Z1, at least about 90% of the imaginary axes Z1 or even all the imaginary axes Z1, of the first structures of the first arrangement is substantially surrounded by the one or more second structures of the second arrangement such that an imaginary perimeter P1 in a region of the second arrangement intersects the at least one or more second structures of the second arrangement along at least about 50% of the perimeter length, along at least about 55% of the perimeter length, along at least about 60% of the perimeter length, along at least about 65% of the perimeter length, along at least about 70% of the perimeter length, along at least about 75% of the perimeter length, along at least about 80% of the perimeter length, along at least about 80% of the perimeter length, along at least about 85% of the perimeter length, along at least about 90% of the perimeter length, along at least about 95% of the perimeter length, or even 100% of the perimeter length, wherein the imaginary perimeter is drawn perpendicular to and around the imaginary axis of a first structure, has an identical shape as that of the perimeter of the first structure and has a size scaled to be greater than at least one times the perimeter of the first structure.
Yet another embodiment of a deformable membrane, according to the present disclosure, is shown in
In some embodiments of deformable membranes of the present disclosure, the first structures of the first arrangement have corresponding imaginary axes aligned perpendicular to and running through the centroids of their first surfaces, at least one of the imaginary axes Z1, at least 25% of the imaginary axes Z1, at least 50% of the imaginary axes Z1, at least 75% of the imaginary axes Z1, at least about 90% of the imaginary axes Z1 or even all the imaginary axes Z1, of the first structures of the first arrangement is substantially surrounded by the one or more second structures of the second arrangement such that an imaginary perimeter P2 in a region of the second arrangement intersects the at least one or more second structures of the second arrangement along at least about 50% of the perimeter length, along at least about 55% of the perimeter length, along at least about 60% of the perimeter length, along at least about 65% of the perimeter length, along at least about 70% of the perimeter length, along at least about 75% of the perimeter length, along at least about 80% of the perimeter length, along at least about 80% of the perimeter length, along at least about 85% of the perimeter length, along at least about 90% of the perimeter length, along at least about 95% of the perimeter length, or even 100% of the perimeter length, wherein the imaginary perimeter is drawn perpendicular to and around the imaginary axis of a first structure, has been enlarged by an arbitrary distance relative to the perimeter of the first surface of the first structure and the arbitrary distance is no greater than the length of the force sensing capacitor element.
In any of the preceding embodiments of the deformable membrane the first arrangement comprising a plurality of first structures, the second arrangement comprising one or more second structures or both of the first arrangement and second arrangement may be a two-dimensional arrangement of structures, i.e. the patterns of the first structures, the patterns of the one or more second structures or both may be a two-dimensional arrangement of structures, e.g. an array of posts, a rectangular grid array, a hexagonal grid array and the like.
Other layers can be included in the deformable membrane including adhesive layers. Adhesives useful in the deformable membranes and force-sensing capacitor elements of the present disclosure include, but are not limited to, pressure sensitive adhesive and cure in place adhesives. Cure in place adhesives include adhesive-solvent solutions where the final adhesive becomes tacky upon removal of solvent. Cure in place adhesives may be cured by actinic radiation, including UV or visible light. Cure in place adhesives may be cured by application of heat, or stated differently elevated temperature (e.g., thermoset polymer). Cure in place adhesives may also be moisture cure adhesives. The adhesives may be used to laminate various layers/components of the deformable members and force-sensing capacitor elements together. Cure in place adhesives are preferred adhesives in the deformable membranes and force sensing capacitor elements of the present disclosure. The deformable member may be a single unitary structure, fabricated for example, by conventional polymer injection molding techniques. The first, second and/or third layers of the deformable membrane may be laminated to the corresponding first structures of the first arrangement and/or second structures of the second arrangement through the use of appropriate adhesive layers. Some or all of the adhesive layers may be the same, i.e. the same chemical composition. All of the adhesive layers may be different, i.e. all have different chemical compositions.
In a given region of a force-sensing capacitor element, the ratio of the sum of the first surface area of the first structures in the region to the surface area of the region may be defined as a first fill factor. The first surfaces 142a of the first structures 142 of any of the embodiments of the present disclosure may have a first fill factor of at least about 1%, at least about 2%, at least about 5%, at least about 7%, or even at least about 10%; less than 90%, less than about 75%, less than about 50% or even less than about 30%. In some embodiments, the first fill factor may be between about 1% and about 90%, between about 2% and about 75%, between about 5% and about 50%, between about 7% and 45% or even between about 10% and 30%. The region of the force sensing capacitor element used to define the first fill factor may have a surface area greater than about 1%, greater than about 5%, greater than about 10%, greater than about 20%, greater than about 30%, greater than about 40% or even greater than about 50% of the total surface area of the force-sensing capacitor element; less than about 99%, less than about 95%, less than about 90%, less than about 80%, less than about 70% or even less than about 60% of the total surface area of the force-sensing capacitor element.
In a given region of a force-sensing capacitor element, the ratio of the sum of the first surface area of the second structures in the region to the surface area of the region may be defined as a second fill factor. The first surfaces 152a of the second structures 152 of any of the embodiments of the present disclosure may have a second fill factor of at least about 1%, at least about 2%, at least about 5%, at least about 7%, or even at least about 10%; less than 90%, less than about 75%, less than about 50% or even less than about 30%. In some embodiments, the second fill factor may be between about 1% and about 90%, between about 2% and about 75%, between about 5% and about 50%, between about 7% and 45%, or even between about 10% and 30%. The region of the force sensing capacitor element used to define the second fill factor may have a surface area greater than about 1%, greater than about 5%, greater than about 10%, greater than about 20%, greater than about 30%, greater than about 40% or even greater than about 50% of the total surface area of the force-sensing capacitor element; less than about 99%, less than about 95%, less than about 90%, less than about 80%, less than about 70% or even less than about 60% of the total surface area of the force-sensing capacitor element.
The total fill factor of first surfaces of the first and second structures, being the sum of the first fill factor and the second fill factor as described above, for any of the embodiments of the present disclosure, may be at least about 2%, at least about 4%, at least about 10%, at least about 14%, or even at least about 20%; less than 90%, less than about 75%, less than about 50% or even less than about 30%. In some embodiments the total fill factor may be between about 2% and about 90%, between about 4% and about 75%, between about 10% and about 50%, between about 14% and 45%, or even between about 20% and 30%. In some embodiments, the total fill factor may be between about 50% and about 99%, between about 60% and about 90%, or even between about 70% and about 80%. The region of the force sensing capacitor element used to define the total fill factor may have a surface area greater than about 1%, greater than about 5%, greater than about 10%, greater than about 20%, greater than about 30%, greater than about 40% or even greater than about 50% of the total surface area of the force-sensing capacitor element; less than about 99%, less than about 95%, less than about 90%, less than about 80%, less than about 70% or even less than about 60% of the total surface area of the force-sensing capacitor element.
In some Examples, the force-sensing capacitor elements comprised a total fill factor of less than 65%, more preferably less than 60%, even more preferably even less than 50%, even more preferably less than 45%, even more preferably less than 40%. In some embodiments, the total fill factor may be between 10% and 65%, in some embodiments between 10% and 60%, in some embodiments between 10% and 50%, in some embodiments between 10% and 40%. In some preferred embodiments, each of the aforementioned total fill factor ranges may exist in combination with greater than 50% of circumference length intersecting second structures, for a circumference of a circle C1 (e.g., imaginary circle C1) having an arbitrary radius R drawn around an axis (e.g., imaginary axis) aligned perpendicular to and running through the centroid of the first surface of a first structure, in some cases greater than 75%, in some cases greater than 80%, in some cases greater than 85%, in some cases greater than 90%, and in some cases greater than 92.5%. For example, in some embodiments, the force-sensing capacitor elements comprise a total fill factor of less than 65% (for example between 10% and 65%), and greater than 50% (for example greater than 75%) of circumference length intersecting second structures, for a circumference of a circle C1 (e.g., imaginary circle C1) having an arbitrary radius R drawn around an axis (e.g., imaginary axis) aligned perpendicular to and running through the centroid of the first surface of a first structure. As another example, in some embodiments, the force-sensing capacitor elements comprise a total fill factor of less than 50% (for example between 10% and 50%), and greater than 80% of circumference length intersecting second structures, for a circumference of a circle C1 (e.g., imaginary circle C1) having an arbitrary radius R drawn around an axis (e.g., imaginary axis) aligned perpendicular to and running through the centroid of the first surface of a first structure. As yet another example, in some embodiments, the force-sensing capacitor elements comprise a total fill factor of less than 40% (for example between 10% and 40%), and greater than 90% of circumference length intersecting second structures, for a circumference of a circle C1 (e.g., imaginary circle C1) having an arbitrary radius R drawn around an axis (e.g., imaginary axis) aligned perpendicular to and running through the centroid of the first surface of a first structure. For the aforementioned levels of total fill factor and amount by which second structures surround first structures, the first surfaces of the first structures are offset from the first surfaces of the second structures; also the first structures are offset from the second structures.
At least one of the first, second and third layers and at least one of the plurality of first structures of the first arrangement, the one or more second structures of the second arrangement and the third structures may include filler particles. Fillers include but are not limited to organic or inorganic particles or fibers, plasticizers, processing aides, thermal or UV/Vis light inhibitors, flame retardants.
Particularly useful materials for any of the first layer, second layer, third layer, first structures, and one or more second structures are silicone elastomers. Silicone materials can be fabricated to include structures according to, for example, U. S. Publ. Patent Application No. 2013/040073 (Pett, et.al.).
The fabrication of first structures and second structures, in registration, according to any of the deformable membranes, individual capacitors or force-sensing capacitor elements set forth herein, can be achieved by methods known in the art, for example through precision molding and casting. Such methods of processing are disclosed in, for example, U.S. Pat. No. 7,767,273 (Huizinga, et. al.).
The deformable membranes of the present disclosure are particularly suited for use in force-sensing capacitor elements and any of the previously described deformable membrane embodiments may be used in any of the force-sensing capacitor element embodiments described herein. In order to fabricate a force-sensing capacitor element with the deformable membranes of the present disclosure, electrodes, e.g. electrode pairs, need to be incorporated with the deformable membranes. The deformable membranes or parts thereof may function as the dielectric of the force-sensing capacitor elements. The positions of the electrodes with respect to the deformable membrane structure, generally, coincide with the deformable regions of the deformable membrane, e.g. the region of the deformable membrane proximate or in contact with the first structures and the second void regions. By positioning the electrodes in such a manner, one can to take advantage of a change in thickness of the deformable membrane and change in height, e.g. height h2, between the second major surface of the second layer and the second major surface of the third layer in the second void regions, in response to an applied force, which will result in a change in capacitance in the deformed region, i.e. a region proximate to the applied force on the surface of the force-sensing capacitor element. Capacitance of one or more of the individual capacitors will change as the deformable membrane compresses in response to an applied force on the first surface of the first layer. As the magnitude of this applied force will correlate with the magnitude of the dimensional changes of the deformable membrane and the magnitude of the dimensional changes of the deformable membrane will cause corresponding changes in the capacitance, a force-force sensing capacitor element may be obtained. A force-sensing capacitor element according to the present disclosure may include more than one capacitor, for example an arrangement or an array of capacitors, thus allowing for measuring the force (or stated differently, pressure) distribution across the force-sensing capacitor element (i.e., positional measurement of force or pressure).
The capacitance of the capacitor, and the change in capacitance with compression, can be measured using any of a variety of known drive electronics. As used herein, the term measure, as related to the capacitance or change in capacitance of a capacitor, may include estimation of the capacitance, as may be expressed in farads. Alternatively, as used herein, the term measure, as related to the capacitance or change in capacitance of a capacitor, may include indirect determination of the magnitude of capacitance of the capacitor through the behavior of that capacitor in a circuit (or, alternatively, the behavior of a circuit that includes the capacitor). The attachment of a capacitor of the present disclosure to a circuit that measures the capacitance is also described herein as attachment of the capacitor to drive electronics that measure the capacitance. Examples of known capacitance measurement circuits are reported in, for example, U.S. Publ. Patent Application Nos. 2010/073323 (Geaghan), 2008/142281 (Geaghan), 2009/167325 (Geaghan), and 2011/115717 (Hable, et. al.), all incorporated herein in their entirety, by reference. The capacitance and the change in capacitance with compression are indirect measures of the force (or stated alternatively, as elaborated upon above, the pressure) applied to the capacitor. In general, the applied force or applied pressure changes the shape of the capacitor due to strain of a material or materials of construction of the capacitor. The change in shape of the capacitor results in a change in capacitance. A capacitive sensing element, i.e. a force-sensing capacitor element, according to the present disclosure may include more than one capacitor, for example an array of capacitors, thus allowing for measuring the force (or stated differently, pressure) distribution across the sensing element (i.e., positional measurement of force or pressure). A capacitive sensing element according to the present disclosure may include spaced apart row and column electrodes (as shown in, for example,
In some embodiments, a force-sensing capacitor element according to the present disclosure may include a deformable membrane according to any one of the previous described deformable membranes, a first electrode embedded within the first layer or proximate to or in contact with the first major surface of the first layer; and a second electrode embedded within the second layer or proximate to or in contact with one of the first major surface of the second layer and the second major surface of the second layer. An electrical charge, positive or negative, may be applied to the first and second electrodes. The electrical charge on the first electrode may be opposite that of the electrical charge on the second electrode. The dimensions of the first and second electrodes are not particularly limited. Their lengths and widths may be of similar dimensions as the dimensions of at least one of that of the first major surfaces of the first and second layer of the deformable membrane. At least one of the first and second electrodes may be planar electrodes. The first and second electrodes may have one or more electrical leads, providing a means of electrical connection to other electrical components and/or devices. Throughout this disclosure, if an electrode is said to be “embedded” in a layer, it can be fully embedded, i.e. fully enclosed by the layer or it can be partially embedded, i.e. part of the electrode may be protruding above a major surface of the layer. Throughout this disclosure, if an electrode is said to be proximate to a major surface of a layer, the electrode may be in contact with the major surface of the layer or one or more additional layers may be interposed between the electrode and the major surface of the layer, with the electrode in contact with the surface of the adjacent additional layer. Several specific, but non-limiting, embodiments are shown in
Referring now to
In other embodiments, a force-sensing capacitor element according to the present disclosure may include a deformable membrane according to anyone of the previous described deformable membranes, at least one electrode pair embedded within the second layer or proximate to or in contact with at least one of the first and second major surfaces of the second layer, wherein each of the at least one electrode pair comprises a first electrode and a second electrode separated by a gap and each of the at least one electrode pair is aligned with a second void region of the second arrangement, through the thickness of the deformable membrane. The force-sensing capacitor element may include a single capacitor or a plurality of capacitors. An electrical charge, positive or negative, may be applied to the first and second electrodes. The electrical charge on the first electrode may be opposite that of the electrical charge on the second electrode. The number of electrode pairs may be the same as the number of the first structures and the correlation between the electrode pairs and the first structures may be a one to one correlation. The number of the at least one electrode pair may be greater than the number of the first structures or the number of the at least one electrode pairs may be less than the number of first structures. The size and shape of the first and second electrodes and the gap are only limited in that they are selected based on the size and shape of the second void regions, in order that the at least one electrode pairs align with the second void regions of the second arrangement, though the thickness of the deformable membrane. The electrode pairs may be contained within or may be aligned, through the thickness of the deformable membrane, within the boundaries of the second void regions of the second arrangement. The at least one electrode pair may be aligned, through the thickness of the deformable membrane, with the first structures of the first arrangement. The dimensions of the first and second electrodes, although being at least somewhat smaller in width (w4 of
Referring now to
In some embodiments, the electrical properties of the material comprising third structures 162 are tailored to enhance the magnitude of capacitance change between electrodes of electrode pairs 510, when third structures 162 are urged into the gap between electrodes of electrode pairs 510. Examples of tailored electrical properties for the third structures include high real part of the relative dielectric constant (also referred to herein as relative permittivity), for example greater than about 3, greater than about 5, greater than about 7, greater than about 10, greater than about 20, greater than about 30, greater than about 40, or even greater than about 50. Other examples of tailored electrical properties for the third structures include high dielectric loss tangent (also referred to herein as loss factor), for example greater than about 0.02, greater than about 0.05, greater than about 0.1, greater than about 0.15, greater than about 0.2, greater than about 0.25, or even greater than about 0.3. Other examples of tailored electrical properties for the third structures include high electrical bulk conductivity, for example, an electrical bulk conductivity greater than about 10−4 siemens/centimeter, greater than about 10−2 siemens/centimeter, greater than about 1 siemen/centimeter, or even greater than about 102 siemens/centimeter.
In yet other embodiments, a force-sensing capacitor element according to the present disclosure may include a deformable membrane according to any one of the previous described deformable membranes, a plurality of first electrodes embedded within the third layer or proximate to or in contact with one of the first and second major surfaces of the third layer wherein each first electrode is aligned with a discrete second void region of the second arrangement comprising one or more structures; and at least one of (i) a plurality of second electrodes embedded within the second layer or proximate to or in contact with one of the first and second major surfaces of the second layer, wherein each second electrode is aligned, through the thickness of the deformable membrane, with a discrete second void region corresponding to a first electrode and, optionally, is aligned with a first electrode, through the thickness of the deformable membrane; and (ii) a third electrode embedded within the second layer or proximate to or in contact with one of the first and second major surfaces of the second layer, wherein the third electrode is aligned, through the thickness of the deformable membrane, with at least two discrete second void regions and, optionally, is aligned with at least two first electrodes, through the thickness of the deformable membrane. When each second electrode is said to be aligned with a discrete second void region corresponding to a first electrode, through the thickness of the deformable membrane, it is meant that a second electrode is aligned with or contained within the same second void region of a first electrode, through the thickness of the deformable membrane. When a second electrode is said to be aligned with a first electrode, it is meant that a projection of the first electrode, through the thickness of the deformable membrane, intersects, at least a portion, of a corresponding projection of the second electrode. The force-sensing capacitor element may include a single capacitor or a plurality of capacitors.
In some embodiments, an electrical charge, positive or negative, is applied to the first, second and third electrodes. In some embodiments, the electrical charge on the first electrode is opposite that of the electrical charge on the second or third electrode. The electrical charge on the first electrodes may be the same and the electrical charge on the second electrodes may be the same, but opposite that of the first electrodes. The electrical charge on the first electrodes may be the same and the electrical charge on the third electrode may be opposite that of the first electrodes. The number of first electrodes and second electrodes may be the same as the number of the first structures and the correlation between the first and second electrodes and the first structures may be a one to one to one correlation. At least one of the number of first electrodes and the number of second electrodes may be greater than the number of the first structures, and at least one of the number of first electrodes and the number of second electrodes may be less than the number of the first structures. The size and shape of first and second electrodes is only limited in that they are selected based on the size and shape of second void regions, in order that first electrodes align with a single second void region of the second arrangement and second electrodes align with the second void regions of the second arrangement, though the thickness of the deformable membrane. At least some of the plurality of first electrodes may be contained within or may be aligned through the thickness of the deformable membrane within the boundaries of the second void regions of the second arrangement. At least some of the plurality of second electrodes may be contained within or may be aligned through the thickness of the deformable membrane within the boundaries of the second void regions of the second arrangement. The dimensions of the first and second electrodes, although being at least somewhat smaller in width (w4 of
Several specific, but non-limiting, embodiments are shown in
In other embodiments, a force-sensing capacitor according to the present disclosure may include a deformable membrane according to anyone of the previous described deformable membranes, a plurality of first electrodes embedded within the second layer or proximate to or in contact with one of the first and second major surfaces of the second layer wherein each first electrode is aligned with a discrete second void region of the second arrangement comprising one or more structures; and a second electrode embedded within the third layer or proximate to or in contact with one of the first and second major surfaces of the third layer, wherein the second electrode is aligned, through the thickness of the deformable membrane, with at least two discrete second void regions corresponding to at least two first electrode and, optionally, is aligned with at least one first electrode, through the thickness of the deformable membrane. When each second electrode is said to be aligned with at least two discrete second void region corresponding to at least two first electrodes, through the thickness of the deformable membrane, it is meant that a second electrode is aligned with or contained within the same two second void region of the first two electrode, through the thickness of the deformable membrane. When a second electrode is said to be aligned with at least one first electrode, it is meant that a projection of the first electrode, through the thickness of the deformable membrane, intersects, at least a portion, of a corresponding projection of the second electrode. The force-sensing capacitor element may include a single capacitor or a plurality of capacitors. In some embodiments, an electrical charge, positive or negative, is applied to the plurality of first electrodes and the second electrode. The electrical charge on the first electrodes may be opposite that of the electrical charge on the second electrode. The electrical charge on the first electrodes may be all the same, but opposite that of the second electrode. The number of first electrodes may be the same as the number of the first structures and the correlation between the first and electrodes and the first structures may be a one to one correlation. The number of first electrodes may be greater than the number of the first structures or the number of first electrodes may be less than the number of the first structures. The size and shape of the first electrodes is only limited in that they are selected based on the size and shape of second void regions, in order that the first electrodes align with a single second void region of the second arrangement, through the thickness of the deformable membrane. At least some of the plurality of first electrodes may be contained within or may be aligned through the thickness of the deformable membrane within the boundaries of the second void regions of the second arrangement. The dimensions of the first electrodes, although being at least somewhat smaller in width (w4 of
Referring now to
In yet other embodiments, a force-sensing capacitor element according to the present disclosure may include a deformable membrane according to anyone of the previous described deformable membranes, a first electrode embedded within the second layer or proximate to or in contact with one of the first and second major surfaces of the second layer, wherein the first electrode is aligned, through the thickness of the deformable membrane, with two or more discrete second void regions of the second arrangement; and a second electrode embedded within the third layer or proximate to or in contact with one of the first and second major surfaces of the third layer, wherein the second electrode is aligned, through the thickness of the deformable membrane, with at least one discrete second void region corresponding to the first electrode and, optionally, is aligned with the first electrode, through the thickness of the deformable membrane. When a second electrode is said to be aligned with a discrete second void region corresponding to a first electrode, through the thickness of the deformable membrane, it is meant that the second electrode is aligned with or contained within the same second void region of the first electrode, through the thickness of the deformable membrane. When a second electrode is said to be aligned with a first electrode, it is meant that a projection of the first electrode, through the thickness of the deformable membrane, intersects, at least a portion, of a corresponding projection of the second electrode. The force-sensing capacitor element may include a single capacitor or a plurality of capacitors. In some embodiments, an electrical charge, positive or negative, is applied to the first and second electrodes. The electrical charge on the first electrode may be opposite that of the electrical charge on the second electrode. The size and shape of first electrode is only limited in that they are selected based on the size and shape of second void regions, in order that the first electrodes align with at least two second void region of the second arrangement, though the thickness of the deformable membrane. The size of the second electrode is not particularly limited. At least one of the first and second electrodes may be substantially planar electrodes. The first and second electrodes may have one or more electrical leads, providing a means of electrical connection to other electrical components and/or devices. Several specific, but non-limiting, embodiments are shown in
In other embodiments, a force-sensing capacitor element includes a deformable membrane having first and second major surfaces, a first electrode and a second electrode, defining a capacitor, wherein the deformable membrane is engineered for its change in effective dielectric constant under compressive stress to combine with its change in thickness under compressive stress to yield an approximately linear dependence between the capacitance per unit area of the capacitor and the compressive stress, e.g the force applied to a major surface of the deformable membrane. The deformation of the deformable membrane at least approximately follows the relationship given in Equation [1], for example, with K being constant to within about 25%, about 10%, about 5%, or even about 2%, over a range of thickness compression, i.e. |□To/To| equal to about 2%, about 5%, about 10%, about 25%, about 50%, or even about 75%.
where:
For force-sensing capacitors of the present disclosure, the coefficient of determination for capacitance versus force is preferably between 0.8000 and 1.000 (e.g., from 0.8001 and 0.9999), more preferably between 0.9000 and 1.0000 (e.g., from 0.9001 and 0.9999), more preferably between 0.9500 and 1.0000 (e.g., from 0.9501 and 0.9999), more preferably between 0.9800 and 1.0000 (e.g., from 0.9801 and 0.9999), or most preferably between 0.9900 and 1.0000 (e.g., from 0.9901 and 0.9999). Relevant ranges of applied force for the aforementioned ranges of RSQ include ranges describable by the factor over which the force is varied. Preferably, the ranges of RSQ described above are associated with force that is varied over a factor of at least 1.5, more preferably at least 2, more preferably at least 3, more preferably at least 4, more preferably at least 5, and most preferably at least 10. In some embodiments, the ranges of RSQ described above are associated with force that is varied over a factor of from 1.5 to 10, and in some embodiments from 2 to 5.
In any of the preceding embodiments of the force-sensing capacitor element, the deformable membrane's first arrangement comprising a plurality of first structures, second arrangement comprising one or more second structures or both the first arrangement and second arrangement may be a two-dimensional arrangement of structures, i.e. the patterns of the first structures, the patterns of the one or more second structures or both may be a two-dimensional arrangement of structures, e.g. a rectangular grid array, a hexagonal grid array and the like.
The electrodes used in the force-sensing capacitor elements of the present disclosure may be metals or metal alloys, including but not limited to, indium-tin-oxide, aluminum, copper, silver and gold. The electrodes used in the force-sensing capacitor elements of the present disclosure may be electrically conductive composites containing one or more conductive particles, fibers, woven or non-woven mats and the like. The conductive particles, fibers, woven or non-woven mats may include the above metal. They also may be non-conductive particles, fibers, woven or non-woven mats that have been coated with a conductive material, e.g. a metal, including but not limited to, aluminum, copper, silver and gold. The electrodes used in the force-sensing capacitor elements may be in the form of thin films, e.g. a thin metal film or thin electrically conductive composite film. The thickness of the electrodes may be between about 0.1 microns and about 200 microns. The thickness may be greater than about 0.5 microns, greater than about 1 microns, greater than about 2 microns, greater than about 3 microns, greater than about 4 microns or even greater than about 5 microns; less than about 50, less than about 40 microns, less than about 30 microns, less than about 20 microns, or even less than 10 microns. The electrodes may be fabricated by know techniques in the art including, but not limited to, techniques commonly used to form indium-tin-oxide traces in present touch screen displays and techniques commonly used to form metal lines and vias in semiconductor manufacturing. Other useful techniques for fabricating the electrodes include screen printing, flexographic printing, inkjet printing, photolithography, etching, and lift-off processing. In embodiments where at least one electrode is embedded within at least one of the first, second and third layers, one or more vias and corresponding metal interconnects, e.g. conductive lines on the surface of a layer, may be used to facilitate electrical contact to the electrode(s).
The force-sensing capacitor elements of the present disclosure may be useful in various electronic devices. Electronic devices include (1) personal computers, (2) displays and monitors, (3) tablets or slate type computing devices, (4) personal electronic and or communication devices, such as for example, smart phones, digital music players and (5) any personal device whose function includes creating, storing or consuming digital media. In another embodiment, an electronic device comprises a force-sensing capacitor element of any of the proceeding embodiments. In yet another embodiment, a touch screen display comprises a force-sensing capacitor element of any of the proceeding embodiments.
Select embodiments of the present disclosure include, but are not limited to, the following:
In a first embodiment, the present disclosure provides a force-sensing capacitor element comprising:
a deformable membrane comprising
a first electrode embedded within the first layer or proximate to or in contact with the first major surface of the first layer; and
a second electrode embedded within the second layer or proximate to or in contact with one of the first major surface of the second layer and the second major surface of the second layer.
In a second embodiment, the present disclosure provides a force-sensing capacitor element comprising:
a deformable membrane comprising
at least one electrode pair embedded within the second layer or proximate to or in contact with at least one of the first and second major surfaces of the second layer, wherein each of the at least one electrode pair comprises a first electrode and a second electrode separated by a gap and each of the at least one electrode pair is aligned with a second void region of the second arrangement, through the thickness of the deformable.
In a third embodiment, the present disclosure provides a force-sensing capacitor element comprising:
a deformable membrane comprising
a plurality of first electrodes embedded within the third layer or proximate to one of the first and second major surfaces of the third layer wherein each first electrode is aligned with a discrete second void region of the second arrangement comprising one or more structures; and
at least one of (i) a plurality of second electrodes embedded within the second layer or proximate to one of the first and second major surfaces of the second layer, wherein each second electrode is aligned, through the thickness of the deformable membrane, with a discrete second void region corresponding to a first electrode and, optionally, is aligned with a first electrode through the thickness of the deformable membrane; and (ii) a third electrode embedded within the second layer or proximate to one of the first and second major surfaces of the second layer, wherein the third electrode is aligned, through the thickness of the deformable membrane, with at least two discrete second void regions, and optionally, is aligned with at least two first electrodes, through the thickness of the deformable membrane.
In a forth embodiment, the present disclosure provides a force-sensing capacitor element comprising:
a deformable membrane comprising
a plurality of first electrodes embedded within the second layer or proximate to one of the first and second major surfaces of the second layer wherein each first electrode is aligned with a discrete second void region of the second arrangement comprising one or more structures; and
a second electrode embedded within the third layer or proximate to one of the first and second major surfaces of the third layer, wherein the second electrode is aligned, through the thickness of the deformable membrane, with at least two discrete second void regions corresponding to at least two first electrodes and, optionally, is aligned with at least one first electrode, through the thickness of the deformable membrane.
In a fifth embodiment, the present disclosure provides a force-sensing capacitor element comprising:
a deformable membrane comprising
a first electrode embedded within the second layer or proximate to one of the first and second major surfaces of the second layer wherein the first electrode is aligned, through the thickness of the deformable membrane, with two or more discrete second void regions of the second arrangement; and
a second electrode embedded within the third layer or proximate to one of the first and second major surfaces of the third layer, wherein the second electrode is aligned, through the thickness of the deformable membrane, with at least one discrete second void region corresponding to the first electrode and, optionally, is aligned with the first electrode, through the thickness of the deformable membrane.
In a sixth embodiment, the present disclosure provides a force-sensing capacitor element according to the first to fifth embodiments, wherein the deformable membrane further comprises a plurality of third structures proximate to or in contact with the second major surface of the third layer wherein each third structure coincides and overlaps, through the thickness of the deformable membrane, with a corresponding first structure of the first arrangement, and the third structures are located in the void regions of the second arrangement.
In a seventh embodiment, the present disclosure provides a force-sensing capacitor element according to the sixth embodiment, wherein the third structures are not in contact with the second major surface of the second layer.
In an eighth embodiment, the present disclosure provides a force-sensing capacitor element according to the first to seventh embodiments, wherein the first structures of the first arrangement have corresponding imaginary axes aligned perpendicular to and running through the centroids of their first surfaces, and wherein at least one of the imaginary axes of the first structures of the first arrangement is substantially surrounded by the one or more structures of the second arrangement such that an imaginary circle in a region of the second arrangement comprising one or more structures, having a radius r drawn around the at least one of the imaginary axes, intersects the at least one or more second structures of the second arrangement along at least 50% of the circle's circumference length.
In a ninth embodiment, the present disclosure provides a force-sensing capacitor element according to the first to eighth embodiments, wherein the first and second layers of the deformable membrane are substantially parallel.
In a tenth embodiment, the present disclosure provides a force-sensing capacitor element according to the first to ninth embodiments, wherein the second and third layers of the deformable membrane are substantially parallel.
In an eleventh embodiment, the present disclosure provides a deformable membrane for a force-sensing capacitor element comprising:
a first layer having first and second major surfaces;
a second layer having first and major second 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 or in contact with the second major surface of the first layer and a second surface facing or in contact with the first major surface of the third layer;
a second arrangement comprising one or more 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 of the one or more second structures has a first surface facing or in contact with the second major surface of the second layer and a second surface facing or in contact with the second major surface of the third layer; and wherein each first surface of the first structures and each first surface of the one or more second structures are offset from one another such that there is no overlap between each first surface of the first structures and each first surface of the one or more second structures, through the thickness of the deformable membrane; and
a plurality of third structures proximate to or in contact with the second major surface of the third layer wherein each third structure coincides and overlaps, through the thickness of the deformable membrane, with a corresponding first structure of the first arrangement, and the third structures are located in the void regions of the second arrangement.
In an twelfth embodiment, the present disclosure provides a deformable membrane for a force-sensing capacitor element comprising according to the eleventh, wherein the third structures are not in contact with the second major surface of the second layer.
In a thirteenth embodiment, the present disclosure provides a deformable membrane for a force-sensing capacitor element comprising:
a first layer having first and second major surfaces;
a second layer having first and major second 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 or in contact with the second major surface of the first layer and a second surface facing or in contact with the first major surface of the third layer, and wherein the first structures of the first arrangement have corresponding imaginary axes aligned perpendicular to and running through the centroids of their first surfaces;
a second arrangement comprising one or more 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 of the one or more second structures has a first surface facing or in contact with the second major surface of the second layer and a second surface facing or in contact with the second major surface of the third layer; and wherein each first surface of the first structures and each first surface of the one or more second structures are offset from one another such that there is no overlap between each first surface of the first structures and each first surface of the one or more second structures, through the thickness of the deformable membrane, and wherein at least one of the imaginary axes of the first structures of the first arrangement is surrounded by the one or more second structures of the second arrangement such that an imaginary circle in a region of the second arrangement, having a radius r drawn around the at least one of the imaginary axes, intersects the at least one or more second structures of the second arrangement along at least 50% of the circle's circumference length.
In a fourteenth embodiment, the present disclosure provides a deformable membrane according to the thirteenth embodiment, wherein at least 50% of the corresponding imaginary axes of the first structures of the first arrangement are surrounded by the one or more second structures of the second arrangement such that an imaginary circle in the region of the second arrangement, having a radius r drawn around the imaginary axes, intersects the at least one or more second structures of the second arrangement along at least 50% of the circle's circumference length.
In a fifteenth embodiment, the present disclosure provides a deformable membrane according to the fourteenth embodiment, wherein all of the corresponding imaginary axes of the first structures of the first arrangement are surrounded by the one or more second structures of the second arrangement such that an imaginary circle in the region of the second arrangement, having a radius r drawn around the imaginary axes, intersects the at least one or more second structures of the second arrangement along at least 50% of the circle's circumference length.
In a sixteenth embodiment, the present disclosure provides a deformable membrane according to the thirteenth to fifteenth embodiments, wherein the at least one of the corresponding imaginary axes of the first structures of the first arrangement is surrounded by the one or more second structures of the second arrangement such that an imaginary circle in the region of the second arrangement, having a radius r drawn around an axis, intersects the at least one or more structures of the second arrangement along at least 70% of the circle's circumference length.
In a seventeenth embodiment, the present disclosure provides a deformable membrane according to the thirteenth to fifteenth embodiments, wherein the at least one of the corresponding imaginary axes of the first structures of the first arrangement is substantially surrounded by the one or more second structures of the second arrangement such that an imaginary circle in the region of the second arrangement, having a radius r drawn around an axis, intersects the at least one or more second structures of the second arrangement along at least 90% of the circle's circumference length.
In an eighteenth embodiment, the present disclosure provides a deformable membrane according to the thirteenth to seventeenth embodiments, wherein the deformable membrane further comprises a plurality of third structures proximate to or in contact with the second major surface of the third layer wherein each third structure coincides and overlaps, through the thickness of the deformable membrane, with a corresponding first structure of the first arrangement comprising a plurality of first structures, and the third structures are located in the void regions of the second arrangement comprising one or more second structures.
In a nineteenth embodiment, the present disclosure provides a deformable membrane according to the eighteenth embodiments, wherein the third structures are not in contact with the second major surface of the second layer.
In a twentieth embodiment, the present disclosure provides a force-sensing capacitor element comprising:
a deformable membrane according to any one of the eleventh to nineteenth embodiments
a first electrode embedded within the first layer or proximate to or in contact with one of the first and second major surfaces of the first layer; and
a second electrode embedded within the second layer or proximate to or in contact with one of the first and second major surfaces of the second layer.
In a twenty-first embodiment, the present disclosure provides a force-sensing capacitor element according to the first to tenth and twentieth embodiments, wherein the first arrangement comprising a plurality of first structures, the second arrangement comprising one or more second structures or both of the first arrangement and second arrangement is a two-dimensional arrangement of structures.
In a twenty-second embodiment, the present disclosure provides a deformable membrane according to any one of the eleventh to nineteenth embodiments, wherein the first arrangement comprising a plurality of first structures, the second arrangement comprising one or more second structures or both of the first arrangement and second arrangement is a two-dimensional arrangement of structures.
In a twenty-third embodiment, the present disclosure provides an electronic device comprising a force-sensing capacitor element according to any one the first to tenth, twentieth and twenty-first embodiments.
In a twenty-fourth embodiment, the present disclosure provides a touch screen display comprising a force-sensing capacitor element according to any one the first to tenth, twentieth and twenty-first embodiments.
In a twenty-fifth embodiment, the present disclosure provides a force-sensing capacitor element according to the first to seventh embodiments, wherein the first structures of the first arrangement have corresponding imaginary axes aligned perpendicular to and running through the centroids of their first surfaces, and wherein at least one of the imaginary axes of the first structures of the first arrangement is substantially surrounded by the one or more second structures of the second arrangement such that an imaginary perimeter in a region of the second arrangement intersects the at least one or more second structures of the second arrangement along at least 50% of the perimeter length, wherein the imaginary perimeter is drawn perpendicular to and around the imaginary axis of a first structure, has an identical shape as that of the perimeter of the first structure and has a size scaled to be greater than at least one times the perimeter of the first structure.
In a twenty-sixth embodiment, the present disclosure provides a force-sensing capacitor element according to the first to seventh embodiments, wherein the first structures of the first arrangement have corresponding imaginary axes aligned perpendicular to and running through the centroids of their first surfaces, and wherein at least one of the imaginary axes of the first structures of the first arrangement is substantially surrounded by the one or more second structures of the second arrangement such that an imaginary perimeter in a region of the second arrangement intersects the at least one or more second structures of the second arrangement along at least 50% of the perimeter length, wherein the imaginary perimeter is drawn perpendicular to and around the imaginary axis of a first structure and has been enlarged by an arbitrary distance relative to the perimeter of the first surface of the first structure and wherein the arbitrary distance is no greater than the length of the force sensing capacitor element.
In a twenty-seventh embodiment, the present disclosure provides a deformable membrane for a force-sensing capacitor element comprising:
a first layer having first and second major surfaces;
a second layer having first and major second 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 or in contact with the second major surface of the first layer and a second surface facing or in contact with the first major surface of the third layer, and wherein the first structures of the first arrangement have corresponding imaginary axes aligned perpendicular to and running through the centroids of their first surfaces;
a second arrangement comprising one or more 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 of the one or more second structures has a first surface facing or in contact with the second major surface of the second layer and a second surface facing or in contact with the second major surface of the third layer; and wherein each first surface of the first structures and each first surface of the one or more second structures are offset from one another such that there is no overlap between each first surface of the first structures and each first surface of the one or more second structures, through the thickness of the deformable membrane, and wherein at least one of the imaginary axes of the first structures of the first arrangement is substantially surrounded by the one or more second structures of the second arrangement such that an imaginary perimeter in a region of the second arrangement intersects the at least one or more second structures of the second arrangement along at least about 50% of the perimeter length, wherein the imaginary perimeter is drawn perpendicular to and around the imaginary axis of a first structure, has an identical shape as that of the perimeter of the first structure and has a size scaled to be greater than at least one times the perimeter of the first structure.
In a twenty-eighth embodiment, the present disclosure provides a deformable membrane for a force-sensing capacitor element comprising:
a first layer having first and second major surfaces;
a second layer having first and major second 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 or in contact with the second major surface of the first layer and a second surface facing or in contact with the first major surface of the third layer, and wherein the first structures of the first arrangement have corresponding imaginary axes aligned perpendicular to and running through the centroids of their first surfaces;
a second arrangement comprising one or more 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 of the one or more second structures has a first surface facing or in contact with the second major surface of the second layer and a second surface facing or in contact with the second major surface of the third layer; and wherein each first surface of the first structures and each first surface of the one or more second structures are offset from one another such that there is no overlap between each first surface of the first structures and each first surface of the one or more second structures, through the thickness of the deformable membrane, and wherein at least one of the imaginary axes of the first structures of the first arrangement is substantially surrounded by the one or more second structures of the second arrangement such that an imaginary perimeter in a region of the second arrangement intersects the at least one or more second structures of the second arrangement along at least about 50% of the perimeter length, wherein the imaginary perimeter is drawn perpendicular to and around the imaginary axis of a first structure, has been enlarged by an arbitrary distance relative to the perimeter of the first surface of the first structure and the arbitrary distance is no greater than the length of the force sensing capacitor element.
In a twenty-ninth embodiment, the present disclosure provides a force-sensing capacitor element 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 or in contact with the second major surface of the first layer and a second surface facing or in contact with the first major surface of the third layer, and
a second arrangement comprising one or more 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 of the one or more second structures has a first surface facing or in contact with the second major surface of the second layer and a second surface facing or in contact with the second major surface of the third layer; and wherein each first surface of the first structures and each first surface of the one or more second structures are offset from one another such that there is no overlap between each first surface of the first structures and each first surface of the one or more second structures, through the thickness of the force-sensing capacitor; wherein
at least one of the first layer, the second layer, and the third layer is a metal.
In a thirtieth embodiment, the present disclosure provides a force-sensing capacitor element according to the twenty-ninth embodiment, wherein the first layer is a metal.
In a thirty-first embodiment, the present disclosure provides a force-sensing capacitor element according to the twenty-ninth to thirtieth embodiments, wherein the second layer is a metal.
In a thirty-second embodiment, the present disclosure provides a force-sensing capacitor element according to the twenty-ninth to thirty-first embodiments, wherein the third layer is a metal.
In a thirty-third embodiment, the present disclosure provides a force-sensing capacitor element according to the twenty-ninth embodiment, wherein the second layer is a metal and the third layer is a metal.
In an thirty-fourth embodiment, the present disclosure provides a force-sensing capacitor element according to the twenty-ninth to thirty-third, wherein the first structures of the first arrangement have corresponding imaginary axes aligned perpendicular to and running through the centroids of their first surfaces, and wherein at least one of the imaginary axes of the first structures of the first arrangement is substantially surrounded by the one or more structures of the second arrangement such that an imaginary circle in a region of the second arrangement comprising one or more structures, having a radius r drawn around the at least one of the imaginary axes, intersects the at least one or more second structures of the second arrangement along at least 50% of the circle's circumference length.
In a thirty-fifth embodiment, the present disclosure provides a force-sensing capacitor according to the thirty-fourth embodiment, wherein at least 50% of the corresponding imaginary axes of the first structures of the first arrangement are surrounded by the one or more second structures of the second arrangement such that an imaginary circle in the region of the second arrangement, having a radius r drawn around the imaginary axes, intersects the at least one or more second structures of the second arrangement along at least 50% of the circle's circumference length.
In a thirty-sixth embodiment, the present disclosure provides a force-sensing capacitor according to the thirty-fifth embodiment, wherein all of the corresponding imaginary axes of the first structures of the first arrangement are surrounded by the one or more second structures of the second arrangement such that an imaginary circle in the region of the second arrangement, having a radius r drawn around the imaginary axes, intersects the at least one or more second structures of the second arrangement along at least 50% of the circle's circumference length.
In a thirty-seventh embodiment, the present disclosure provides a force-sensing capacitor according to the thirty-fourth to thirty-sixth embodiments, wherein the at least one of the corresponding imaginary axes of the first structures of the first arrangement is surrounded by the one or more second structures of the second arrangement such that an imaginary circle in the region of the second arrangement, having a radius r drawn around an axis, intersects the at least one or more structures of the second arrangement along at least 70% of the circle's circumference length.
In a thirty-eighth embodiment, the present disclosure provides a force-sensing capacitor according to the thirty-fourth to thirty-sixth embodiments, wherein the at least one of the corresponding imaginary axes of the first structures of the first arrangement is substantially surrounded by the one or more second structures of the second arrangement such that an imaginary circle in the region of the second arrangement, having a radius r drawn around an axis, intersects the at least one or more second structures of the second arrangement along at least 90% of the circle's circumference length.
In a thirty-ninth embodiment, the present disclosure provides a force-sensing capacitor according to the twenty-ninth to thirty-eighth embodiments, wherein the force-sensing capacitor further comprises a plurality of third structures proximate to or in contact with the second major surface of the third layer wherein each third structure coincides and overlaps, through the thickness of the force-sensing capacitor, with a corresponding first structure of the first arrangement comprising a plurality of first structures, and the third structures are located in the void regions of the second arrangement comprising one or more second structures.
In a fortieth embodiment, the present disclosure provides a force-sensing capacitor according to the thirty-ninth embodiment, wherein the third structures are not in contact with the second major surface of the second layer.
Acrylic Resin 1 was a solution of 59.70 wt-% R1, 19.90 wt-% R2, 19.90 wt-% R3, and 0.5 wt-% PI1.
Acrylic Resin 2 was a 10 wt-% solution of Acrylic Resin 1 dissolved in isopropyl alcohol (90% isopropyl alcohol).
Force-sensing capacitor elements comprising deformable membranes were tested for uniaxial compressibility and for their capacitance change versus uniaxial applied force applied normal to their major surfaces (same as capacitance per unit area change versus uniaxial pressure). The apparatus for testing comprised a TA Instruments ARES Rheometer (TA Instruments, New Castle Del.) and an Agilent 4284 Precision LCR Meter (Agilent Technologies, Santa Clara, Calif.). The rheometer was used for application of a controlled uniaxial load and measurement of displacement (for determination of reported sample thickness) under the load. The LCR meter was used for measurement of capacitance and dissipation factor at 200 kHz, simultaneously with the application of the normal load and measurement of sample thickness. Measurements of capacitance and dissipation factor were made as load was increased and then decreased, with the load being held at set levels between and including 0 and 1 kilogram for approximately 15 seconds for each measurement. The top shaft of the rheometer were terminated with a rectangular conductive platen made of brass, with lateral dimensions of approximately 1.03 centimeter by approximately 1.13 centimeter, giving an area of approximately 1.16 square centimeters. The bottom shaft of the rheometer was terminated with a circular conductive platen made of stainless steel, with diameter of 2.5 centimeters. The deformable membrane components of Examples 1-4, Comparative Example 5, and Examples 6-8 were all cut to approximately the same lateral dimensions of the top platen and aligned within the platens. Thus, 1.16 square centimeters is the area of each of the parallel plate capacitors and is the area over which the reported loads (also referred to herein as forces) were distributed. The pressure applied to the force-sensing capacitor elements and the deformable membranes was equal to the reported loads divided by 1.16 centimeters squared (i.e., square centimeters, also denoted cm̂2). The capacitance per unit area of the force-sensing capacitor elements was equal to the reported capacitance values divided by 1.16 centimeters squared. When connected to a force-sensing capacitor element of any of Examples 1-8, the LCR meter constituted drive electronics used to measure the capacitance of the capacitor element and the change in capacitance of the capacitor element with compression.
Force-sensing capacitor elements according to
Tools were fabricated for molding structures onto the major surfaces of the third layer. Each tool comprised a pattern of polyimide film (0.002 inch thick) applied to a sheet of precision rolled aluminum sheet stock (Lorin Industries Inc., Alloy 1085, 0.025 inch thick). The tool was patterned by excimer laser ablation as described in U.S. Pat. No. 6,285,001. The resulting relief height of the tooling was approximately 50 micrometers, the thickness of the polyimide film. For each structured core of Examples 1-4, a first tool was so prepared for molding first structures and a second tool was so prepared for molding second structures.
A plurality of first structures were formed onto the first surface of the third layer by molding Acrylic Resin 1 between the first surface of the third layer and a first tool. Acrylic Resin 1 was applied to the first tool which had been heated in an air-circulation batch oven set at 75 deg. C. Once the resin was allowed to wet-out the surface of the tool (about 2 minutes), the tool with liquid resin layer was introduced into a batch vacuum oven set at 50 deg, C. and vacuum was applied. Vacuum was allowed to reach ˜25 in. Hg then vacuum was turned off and sample was allowed to slowly return to atmospheric pressure. Next, the sheet of the PET Film 1 was laid over tool/resin stack and laminated using a flat-bed laminator equipped with a 4″ silicone rubber roll of approximately 50 Durameter. The resulting multilayer stack (first tool, resin layer, and PET layer) was then cured in a broad spectrum carbon lamp UV curing chamber with a belt speed of 50 FPM. The stack was processed through the UV system three times then allowed to return to room temperature. At this point, a sharp tool is inserted between first tool surface and microreplicated film surface to initiate separation of the two layers (first tool and film), and continuous upward force was applied to the film to facilitate separation from the tool.
A plurality of second structures were formed onto the second surface of the third layer by molding Acrylic Resin 1 between the second surface of the third layer and the second tool. The second structures were molded according to a similar procedure as used for the first structures, with two modifications. The first modification was the temporary addition of a 0.003 inch thick film of polyethyeleneterepthalate (PET) was placed between the first structures of the third layer and the silicone rubber roller of the flat-bed laminator. This 0.003 inch thick film of PET was removed after the lamination step and was not a component in the final articles. The second modification to the procedure was the manual offset-placement of the first structures with respect to the second tool, to yield structured cores with first structures offset from second structures.
The first structures were connected by a land region having a height that was estimated to be less than 25 micrometers (i.e., less than 50% of the height of the first structures). The second structures were connected by a land region having a height that was estimated to be less than 25 micrometers (i.e., less than 50% of the height of the second structures). A third layer for each of Examples 1-4, with its first structures and its second structures, is referred to herein as a structure core.
The structured cores of Examples 1-4 were fabricated with designs according to
For each capacitor element, a value of capacitance change per unit force (dC/dF, in units of femtofarads per gram force) was calculated using the slope of a regression fit of capacitance vs. force, from 200 grams force (1.96 newtons) to 1000 grams force (9.8 newtons). Values of dC/dF are also reported in Table 1. Values of the coefficient of determination (denoted RSQ) for capacitance per unit area versus force per unit area (same as coefficient of determination for capacitance versus force) in the regime of 200 grams force to 1000 grams force over the sample area of 1.16 square centimeters, a measure of the linearity of the capacitance versus force response, are also given in Table 1. Regarding the RSQ values in Table 1, force was varied over a factor of 5 (1000 grams force divided by 200 grams force).
The structured cores 900 of Examples 1-4 were used to prepare deformable membranes of Comparative Example 5 and Examples 6-8, respectively. Each of the deformable membranes of Comparative Example 5 through Example 8 included a first layer 110 and a second layer 120, each comprising a polymer film, bonded to structures 142 and structures 152, respectively. Furthermore, gold electrodes were applied to the first major surface 110a of the first layer 110 and the first major surface 120a of the second layer 120 (with reference to
Each deformable membrane of Comparative Examples 5 through Example 8 was assembled as follows. A first piece of PET Film 2 of approximately A4 size (approximately 20 centimeters by 30 centimeters) was provided as a first layer with a first major surface and a second major surface (primed side). A second piece of PET Film 2 of approximately A4 size (approximately 20 centimeters by 30 centimeters) was provided as a second layer with a first major surface and a second major surface (primed side). The second major surfaces of the first and second layers were resin bonded to the first and second structures, respectively, according to the following procedure. The respective piece of PET Film 2 was applied to a flat sheet of glass with the primed side facing up. A layer of Acrylic Resin 2 was applied to the primed face of the piece of PET Film 2 using a self- contained sprayer system (Chicago Aerosol, Bridgeview, Ill.). Application of this layer can be facilitated by any atomization system such as an automotive spray gun or an air brush system. Optionally, for the preparation of Acrylic Resin 2, the concentration of Acrylic Resin 1 in isopropanol can be increased, for example to 20 wt-%. The glass plate, PET Film 2 and Acrylic Resin 2 stack was then placed in a forced air circulation batch furnace set at 50 Deg. C. and Isopropyl Alcohol was allowed to evaporate off over 5 minutes. One at a time, each respective first and second structures that had been molded onto the third layer were laid down into the layer of Acrylic Resin 2, laminated with flat-bed laminator using a clean piece of PET between sample and roll, then cured in the aforementioned UV curing system. The first structures were bonded to the second major surface of the first layer. The second structures were bonded to the second major surface of the second layer.
Table 3 reports measured thickness and capacitance versus applied load for the force-sensing capacitor elements of Comparative Example 5 through Example 8.
| Number | Date | Country | |
|---|---|---|---|
| 62034206 | Aug 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15325637 | Jan 2017 | US |
| Child | 15727922 | US |
