Manipulating center console components utilizing active material actuation

A center console comprising a manipulable structural component, such as a pivotal lid, sliding armrest, tambour door, or pivotal cup holder, and at least one active material actuator including an active material element operable to undergo a reversible change, drivenly coupled to the component, and configured to autonomously cause and/or enable the component to be manipulated as a result of the change.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure generally relates to center consoles having manipulable components, and in particular, to a center console that utilizes active material actuation to manipulate at least one component.

2. Discussion of the Prior Art

Center consoles, such as those used in automotive vehicles, typically comprise a number of manipulable and/or reconfigurable components that provide increased comfort and functionality for an adjacently seated occupant(s). These components exemplarily include lids, storage compartment panels, and cup holders that selectively deploy and stow, and an armrest that slides in the fore-aft direction. Traditionally, these components have been manually manipulated, which presented and continues to present various concerns in the art. For example, it is appreciated that manual drives may present a distraction from operating the vehicle, often require complex physical motion and dexterity that is difficult for some users to perform, and are prone to the application of an improper actuation force and resultant damage. As a result, mechanically driven components that utilize such actuators as motors, solenoids, and the like, have been increasingly introduced to provide autonomous manipulation. These types of actuators, however, also present concerns in the art, including, for example, the addition of bulky mechanical devices that take up packaging space, add an otherwise undesirable amount of mass, and generate acoustic and electromagnetic field noise.

BRIEF SUMMARY OF THE INVENTION

Responsive to these and others concerns, the present invention recites a center console that utilizes active material actuation to manipulate at least one component. As such, the invention is useful for providing autonomous functionality, either on-demand or in response to sensory feedback, while increasing packaging space, reducing added mass, and reducing noise, in comparison to prior art mechanical actuators. The invention is further useful for providing a reconfigurable console that better accommodates users of varying dimensions.

In general, the inventive console is adapted for use with at least one adjacent seat, such as those found in transportation vehicles, and comprises at least one manipulable structural component and at least one active material actuator. The actuator(s) comprises an active material element that is operable to undergo a reversible change in a fundamental property when exposed to or occluded from an activation signal. The actuator is drivenly coupled to the component(s), so as to autonomously manipulate the component, and/or release a locking mechanism, so as to enable manual manipulation, as a result of the change. Exemplary components include a sliding armrest, pivotal cup holder, reconfigurable and translatable storage compartments, and articulating tambour doors.

The disclosure, including various configurations for implementation and features, such as locking mechanism, strain relief mechanism, and the use of stored energy elements, may be understood more readily by reference to the following detailed description of the various features of the disclosure and the examples included therein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIGS. 1-5b, the present invention broadly concerns a center console10comprising at least one manipulable component12that is drivenly coupled to an active material actuator14, i.e., an actuator consisting of and utilizing the force or displacement generated by at least one active material element16, as further described herein. More preferably, the present invention presents a fully adjustable center console10that utilizes active material actuation to silently cause or enable the manipulation of a plurality of components12. The preferred component12and actuator14are cooperatively configured such that the ability to manually manipulate the component12is retained, and as such, presents a manual override, where, for example, an electrical system failure (or otherwise inoperable activation source) is encountered. Exemplary components12include a pivotal console lid18(FIGS. 2-2b), a sliding armrest20(FIGS. 3a-c), a sliding tambour door22(FIG. 4), and a pivotal cup holder24(FIGS. 5a,b); however, it is certainly appreciated that other components, such as a translatable cup holder, a rollable top cover, and a reconfigurable interior compartment panel (not shown) may be employed as well. Furthermore, the console10itself may present a component12, where the actuator14causes the console10in its entirety to be manipulated (e.g., translated).

It is appreciated that the term “center console”, as used herein, shall be afforded its ordinary meaning as understood by those of ordinary skill in the art, and includes those furniture embodiments typically comprising at least a subset of the aforementioned components12and situated intermediate first and second seats25such as those found within transportation vehicles (e.g., automobiles, trucks, airplanes, boats, etc.)100, as exemplarily presented inFIG. 1. The present invention improves upon the functionality and convenience provided by center consoles to seated occupants (not shown).

I. Active Material Discussion and Function

As used herein the term “active material” shall be afforded its ordinary meaning as understood by those of ordinary skill in the art, and includes any material or composite that exhibits a reversible change in a fundamental (e.g., chemical or intrinsic physical) property, when exposed to an external signal source. Thus, active materials shall include those compositions that can exhibit a change in stiffness properties, shape and/or dimensions in response to the activation signal, which can take the type for different active materials, of electrical, magnetic, thermal and like fields.

Suitable active materials for use with the present invention include but are not limited to shape memory materials such as shape memory alloys. Shape memory materials generally refer to materials or compositions that have the ability to remember their original at least one attribute such as shape, which can subsequently be recalled by applying an external stimulus. As such, deformation from the original shape is a temporary condition. In this manner, shape memory materials can change to the trained shape in response to an activation signal. Exemplary active materials include the afore-mentioned shape memory alloys (SMA), electroactive polymers (EAP), ferromagnetic SMA's, piezoelectric polymers, piezoelectric ceramics, electrostrictives, and magnetostrictives, various combinations of the foregoing materials, and the like.

More particularly, shape memory alloys (SMA's) generally refer to a group of metallic materials that demonstrate the ability to return to some previously defined shape or size when subjected to an appropriate thermal stimulus. Shape memory alloys are capable of undergoing phase transitions in which their yield strength, stiffness, dimension and/or shape are altered as a function of temperature. The term “yield strength” refers to the stress at which a material exhibits a specified deviation from proportionality of stress and strain. Generally, in the low temperature, or martensite phase, shape memory alloys can be plastically deformed and upon exposure to some higher temperature will transform to an austenite phase, or parent phase, returning to their shape prior to the deformation. Materials that exhibit this shape memory effect only upon heating are referred to as having one-way shape memory. Those materials that also exhibit shape memory upon re-cooling are referred to as having two-way shape memory behavior.

Shape memory alloys exist in several different temperature-dependent phases. The most commonly utilized of these phases are the so-called Martensite and Austenite phases discussed above. In the following discussion, the martensite phase generally refers to the more deformable, lower temperature phase whereas the austenite phase generally refers to the more rigid, higher temperature phase. When the shape memory alloy is in the martensite phase and is heated, it begins to change into the austenite phase. The temperature at which this phenomenon starts is often referred to as austenite start temperature (As). The temperature at which this phenomenon is complete is called the austenite finish temperature (Af).

When the shape memory alloy is in the austenite phase and is cooled, it begins to change into the martensite phase, and the temperature at which this phenomenon starts is referred to as the martensite start temperature (Ms). The temperature at which austenite finishes transforming to martensite is called the martensite finish temperature (Mf). Generally, the shape memory alloys are softer and more easily deformable in their martensitic phase and are harder, stiffer, and/or more rigid in the austenitic phase. In view of the foregoing, a suitable activation signal for use with shape memory alloys is a thermal activation signal having a magnitude to cause transformations between the martensite and austenite phases.

Shape memory alloys can exhibit a one-way shape memory effect, an intrinsic two-way effect, or an extrinsic two-way shape memory effect depending on the alloy composition and processing history. Annealed shape memory alloys typically only exhibit the one-way shape memory effect. Sufficient heating subsequent to low-temperature deformation of the shape memory material will induce the martensite to austenite type transition, and the material will recover the original, annealed shape. Hence, one-way shape memory effects are only observed upon heating. Active materials comprising shape memory alloy compositions that exhibit one-way memory effects do not automatically reform, and will likely require an external mechanical force to reform the shape.

Intrinsic and extrinsic two-way shape memory materials are characterized by a shape transition both upon heating from the martensite phase to the austenite phase, as well as an additional shape transition upon cooling from the austenite phase back to the martensite phase. Active materials that exhibit an intrinsic shape memory effect are fabricated from a shape memory alloy composition that will cause the active materials to automatically reform themselves as a result of the above noted phase transformations. Intrinsic two-way shape memory behavior must be induced in the shape memory material through processing. Such procedures include extreme deformation of the material while in the martensite phase, heating-cooling under constraint or load, or surface modification such as laser annealing, polishing, or shot-peening. Once the material has been trained to exhibit the two-way shape memory effect, the shape change between the low and high temperature states is generally reversible and persists through a high number of thermal cycles. In contrast, active materials that exhibit the extrinsic two-way shape memory effects are composite or multi-component materials that combine a shape memory alloy composition that exhibits a one-way effect with another element that provides a restoring force to reform the original shape.

The temperature at which the shape memory alloy remembers its high temperature form when heated can be adjusted by slight changes in the composition of the alloy and through heat treatment. In nickel-titanium shape memory alloys, for instance, it can be changed from above about 100° C. to below about −100° C. The shape recovery process occurs over a range of just a few degrees and the start or finish of the transformation can be controlled to within a degree or two depending on the desired application and alloy composition. The mechanical properties of the shape memory alloy vary greatly over the temperature range spanning their transformation, typically providing the system with shape memory effects, superelastic effects, and high damping capacity.

Suitable shape memory alloy materials include, without limitation, nickel-titanium based alloys, indium-titanium based alloys, nickel-aluminum based alloys, nickel-gallium based alloys, copper based alloys (e.g., copper-zinc alloys, copper-aluminum alloys, copper-gold, and copper-tin alloys), gold-cadmium based alloys, silver-cadmium based alloys, indium-cadmium based alloys, manganese-copper based alloys, iron-platinum based alloys, iron-platinum based alloys, iron-palladium based alloys, and the like. The alloys can be binary, ternary, or any higher order so long as the alloy composition exhibits a shape memory effect, e.g., change in shape orientation, damping capacity, and the like.

Thus, for the purposes of this invention, it is appreciated that SMA's exhibit a modulus increase of 2.5 times and a dimensional change of up to 8% (depending on the amount of pre-strain) when heated above their Martensite to Austenite phase transition temperature. It is appreciated that thermally induced SMA phase changes are one-way so that a biasing force return mechanism (such as a spring) would be required to return the SMA to its starting configuration once the applied field is removed. Joule heating can be used to make the entire system electronically controllable. Stress induced phase changes in SMA are, however, two way by nature. Application of sufficient stress when an SMA is in its Austenitic phase will cause it to change to its lower modulus Martensitic phase in which it can exhibit up to 8% of “superelastic” deformation. Removal of the applied stress will cause the SMA to switch back to its Austenitic phase in so doing recovering its starting shape and higher modulus.

Ferromagnetic SMA's (FSMA's), which are a sub-class of SMAs, may also be used in the present invention. These materials behave like conventional SMA materials that have a stress or thermally induced phase transformation between martensite and austenite. Additionally FSMA's are ferromagnetic and have strong magnetocrystalline anisotropy, which permit an external magnetic field to influence the orientation/fraction of field aligned martensitic variants. When the magnetic field is removed, the material may exhibit complete two-way, partial two-way or one-way shape memory. For partial or one-way shape memory, an external stimulus, temperature, magnetic field or stress may permit the material to return to its starting state. Perfect two-way shape memory may be used for proportional control with continuous power supplied. External magnetic fields are generally produced via soft-magnetic core electromagnets in automotive applications, though a pair of Helmholtz coils may also be used for fast response.

Suitable piezoelectric materials include, but are not intended to be limited to, inorganic compounds, organic compounds, and metals. With regard to organic materials, all of the polymeric materials with non-centrosymmetric structure and large dipole moment group(s) on the main chain or on the side-chain, or on both chains within the molecules, can be used as suitable candidates for the piezoelectric film. Exemplary polymers include, for example, but are not limited to, poly(sodium 4-styrenesulfonate), poly (poly(vinylamine)backbone azo chromophore), and their derivatives; polyfluorocarbons, including polyvinylidenefluoride, its co-polymer vinylidene fluoride (“VDF”), co-trifluoroethylene, and their derivatives; polychlorocarbons, including poly(vinyl chloride), polyvinylidene chloride, and their derivatives; polyacrylonitriles, and their derivatives; polycarboxylic acids, including poly(methacrylic acid), and their derivatives; polyureas, and their derivatives; polyurethanes, and their derivatives; bio-molecules such as poly-L-lactic acids and their derivatives, and cell membrane proteins, as well as phosphate bio-molecules such as phosphodilipids; polyanilines and their derivatives, and all of the derivatives of tetramines; polyamides including aromatic polyamides and polyimides, including Kapton and polyetherimide, and their derivatives; all of the membrane polymers; poly(N-vinyl pyrrolidone) (PVP) homopolymer, and its derivatives, and random PVP-co-vinyl acetate copolymers; and all of the aromatic polymers with dipole moment groups in the main-chain or side-chains, or in both the main-chain and the side-chains, and mixtures thereof.

Piezoelectric materials can also comprise metals selected from the group consisting of lead, antimony, manganese, tantalum, zirconium, niobium, lanthanum, platinum, palladium, nickel, tungsten, aluminum, strontium, titanium, barium, calcium, chromium, silver, iron, silicon, copper, alloys comprising at least one of the foregoing metals, and oxides comprising at least one of the foregoing metals. Suitable metal oxides include SiO2, Al2O3, ZrO2, TiO2, SrTiO3, PbTiO3, BaTiO3, FeO3, Fe3O4, ZnO, and mixtures thereof and Group VIA and JIB compounds, such as CdSe, CdS, GaAs, AgCaSe2, ZnSe, GaP, InP, ZnS, and mixtures thereof. Preferably, the piezoelectric material is selected from the group consisting of polyvinylidene fluoride, lead zirconate titanate, and barium titanate, and mixtures thereof.

Electroactive polymers include those polymeric materials that exhibit piezoelectric, pyroelectric, or electrostrictive properties in response to electrical or mechanical fields. An example of an electrostrictive-grafted elastomer with a piezoelectric poly(vinylidene fluoride-trifluoro-ethylene) copolymer. Materials suitable for use as an electroactive polymer may include any substantially insulating polymer or rubber (or combination thereof) that deforms in response to an electrostatic force or whose deformation results in a change in electric field. Exemplary materials suitable for use as a pre-strained polymer include silicone elastomers, acrylic elastomers, polyurethanes, thermoplastic elastomers, copolymers comprising PVDF, pressure-sensitive adhesives, fluoroelastomers, polymers comprising silicone and acrylic moieties, and the like. Polymers comprising silicone and acrylic moieties may include copolymers comprising silicone and acrylic moieties, polymer blends comprising a silicone elastomer and an acrylic elastomer, for example.

Materials used as an electroactive polymer may be selected based on one or more material properties such as a high electrical breakdown strength, a low modulus of elasticity—(for large or small deformations), a high dielectric constant, and the like. In one embodiment, the polymer is selected such that it has an elastic modulus at most about 100 MPa. In another embodiment, the polymer is selected such that it has a maximum actuation pressure between about 0.05 MPa and about 10 MPa, and preferably between about 0.3 MPa and about 3 MPa. In another embodiment, the polymer is selected such that is has a dielectric constant between about 2 and about 20, and preferably between about 2.5 and about 12. The present disclosure is not intended to be limited to these ranges. Ideally, materials with a higher dielectric constant than the ranges given above would be desirable if the materials had both a high dielectric constant and a high dielectric strength. In many cases, electroactive polymers may be fabricated and implemented as thin films. Thickness suitable for these thin films may be below 50 micrometers.

As electroactive polymers may deflect at high strains, electrodes attached to the polymers should also deflect without compromising mechanical or electrical performance. Generally, electrodes suitable for use may be of any shape and material provided that they are able to supply a suitable voltage to, or receive a suitable voltage from, an electroactive polymer. The voltage may be either constant or varying over time. In one embodiment, the electrodes adhere to a surface of the polymer. Electrodes adhering to the polymer are preferably compliant and conform to the changing shape of the polymer. Correspondingly, the present disclosure may include compliant electrodes that conform to the shape of an electroactive polymer to which they are attached. The electrodes may be only applied to a portion of an electroactive polymer and define an active area according to their geometry. Various types of electrodes suitable for use with the present disclosure include structured electrodes comprising metal traces and charge distribution layers, textured electrodes comprising varying out of plane dimensions, conductive greases such as carbon greases or silver greases, colloidal suspensions, high aspect ratio conductive materials such as carbon fibrils and carbon nanotubes, and mixtures of ionically conductive materials.

II. Exemplary Configurations and Applications

Both the lid18and armrest20are caused or enabled to pivot, so as to selectively allow access to or cover a storage space defined by the compartment26by an active material actuator14. For example, the lid18may be lockingly engaged with the compartment26, through at least one spring-biased pawl (or pin)30configured to engage a corresponding number of catches32(FIGS. 2-2b), and released by an SMA wire16. More preferably, the wire16is drivenly coupled to a linkage system (not shown) configured to ensure uniformity of disengagement by the pawls30. The pawls30may be caused to pivot about an axis or translatably retract. Alternatively, the pawls30may be situated within the compartment26and the catches32defined by the lid18based on packing and aesthetic concerns. As shown inFIG. 2, for example, first and second pawls30are disposed near the front edge and along the lateral sides of the lid18; and the catches32are defined near the front edge and within the lateral sides of the compartment26.

In the illustrated embodiment, the hinge28is coaxially aligned with and biased towards the open condition (FIG. 2b) by at least one actuating spring34, such that upon disengagement of the pawls30and catches32, the console lid18is forced to pivot about an axis, p, defined thereby due to the force of the spring34. More preferably, a helical torsion spring34is employed to minimize packing requirements. The rotation of the lid18is preferably halted by a stop36coupled to either the lid18or compartment26, so as to prevent over-extension to the lid18(FIG. 2b). It is appreciated that the stop36may be integrally formed with the lid18. The lid18may be manually closed by overpowering the spring34, so that the pawls30re-engage the catches32(with the actuator14in the deactivated and cooled condition). Alternatively, an active material actuator14may be employed to produce a moment about the hinge axis, or a torsional actuator such as an SMA torque drive (not shown) may be employed.

As shown inFIGS. 3a-c, another embodiment of the console10concerns the aforementioned armrest20slidably coupled to the lid18and/or compartment26. The armrest20is preferably coupled to an active material actuator14operable, upon activation, to drive the armrest20towards one or more adjusted positions. Where the actuator14presents a contracting tensile element, such as the illustrated SMA wire16, it is appreciated that the inability of the element16to carry a compressive load enables the armrest20(and other components12) to be manually manipulated, by causing slack in the element16in lieu of contraction. A return spring38coupled to the armrest20preferably returns the armrest20to the original position upon cessation of the activation signal.

More preferably, to drive the armrest20, the actuator14(e.g., SMA wire16) is coupled to a gear transmission40configured to magnify displacement. For example, upon activation, a one-way driving gear42may be driven by a rack44through a one-way intermediary46; the intermediary46being biased towards engagement with the rack44and the driving gear42(FIG. 3c). The rack44is drivenly coupled to the actuator14(e.g., SMA wire16) and a return spring38, which together work antagonistically to produce a ratcheting action. That is to say, the rack44defines a plurality of sloped teeth44a(FIG. 3c) that, when translated in a first direction, causes the engaged intermediary to rotate, and, when translated in the opposite direction, pushes the intermediary46outwardly, so as to be disengaged. The intermediary46presents sufficient depth, such that it concurrently engages and disengages the rack44and driving gear42. Causing the engaged intermediary46to rotate drives the driving gear42, which in turn drives a driven gear48. Finally, the driven gear48drives a horizontal rack50fixedly attached to the armrest20.

The gears42,46,48are preferably configured such that the displacement caused by the element16is amplified to achieve a desired, predetermined distance or “stroke.” InFIG. 3b, the return spring38opposes the displacement of the armrest20and stores energy when the armrest20translates to an adjusted position. The inability for the driving and intermediary gears42,46to rotate in the opposite direction locks the armrest20in the adjusted position. To enable the armrest20to return, the driving gear42preferably includes a sector52absent teeth (or “bald spot”). After a predetermined number of activations, the driven gear48encounters the sector52and becomes free to rotate in the non-driven direction at the urging of the return spring38. The armrest20is caused to return to the home position (e.g., one of fore and aft positions shown inFIG. 3a). The sector52presents an angular displacement based upon the gear ratio and desired stroke length per activation cycle, so as to be encountered periodically, wherein the period is equivalent to the number of positions to be achieved.

More preferably, the console10includes a plurality of driving gears42, which along with the driven gear48, presents differing gear ratios. A second actuator (not shown) or a manual mechanism causes a gear shift to a second driving gear42, so that the displacement caused by element16is modified to achieve another predetermined stroke. Multiple stroke lengths can be achieved by selecting one of a plurality of actuators14(e.g., SMA wires of differing lengths) instead of alternate gears42. Finally, it is also appreciated that exposing the element16to differing activation signals and/or over differing activation periods may also cause the stroke length to be modified.

Alternatively, the actuator14may be used to release the armrest20, so as to enable manual manipulation. In this configuration, for example, the console10may further comprise a locking mechanism (e.g., latch, detent, etc.)54that holds the armrest20in discreet predetermined stroke positions, as shown inFIG. 3b. Here, at least one ball bearing56is situated in a longitudinal hole58defined by the armrest20(or compartment26). A detent spring60forces the bearing56into one of several shallow depressions62formed in the other of said armrest20or compartment26. This holds the armrest20in a fixed position relative to the compartment26, even when the element16has been cooled and the return spring38caused to store energy.

Translation of the armrest20caused by the actuator14is preferably sufficient to overcome the detent spring60and dislodge the ball bearing56from the depression62. In that sense, it is appreciated that a single actuator14may be used to first release the locking mechanism54and then manipulate the component12. Alternatively, a separate actuator14, such as a bow-string SMA wire entrained within holes defined by the bearings56(FIG. 3b) may be activated so as to release the detent. Here, the wire16and signal are cooperatively configured to present a brief (e.g., 1-2 sec) period, so that after adjustment, each ball bearing(s)56is forced into another depression62by the associated spring58.

Another embodiment is shown inFIG. 4, wherein the component12includes a tambour style door22operable to selectively enclose a storage compartment26. In the illustrated example, the door22is entrained within a plurality of lateral tracks64defined by the compartment12and wound about a lower spool (not shown) to achieve open and closed conditions. An actuator14(e.g., a shape memory alloy wire16) nests inside at least one track64and is drivenly coupled to the door22. When the wire16is activated, the door22is caused to unwind so as to cover the storage space of the compartment26. Thus, here, as throughout the disclosure, it is appreciated that the wire16is of sufficient length, constitution, and diameter, to effect the intended displacement. The door22may be caused to open (or downwardly scroll) by gravitational forces, a torsional spring (also not shown) engaging the spool, or a spring66coaxially aligned with the wire16in the track64(FIG. 4). A retractable door stop68is optionally positioned along the track64to limit access to the storage compartment26, and more preferably, the stop68is slidable between fully opened, and closed positions, wherein with respect to the latter, the stop68acts as a locking mechanism that retains the door22in the closed condition, after the wire16cools.

FIGS. 5a,bshow yet another exemplary embodiment, wherein the component12is a selectively deployed cup holder24. In the illustrated embodiment, the cup holder24is pivotally coupled to the console compartment/housing26so as to define an axis, p. An active material actuator14is coupled to the console10and preferably includes a plurality of active material elements16. As shown inFIG. 5b, at least one element16amay be operable to cause a clockwise rotation about the axis p, and at least one element16bmay be drivenly coupled to the cup holder24, so as to create a counterclockwise rotation about the axis p, corresponding to opening and closing. Alternatively, it is appreciated that manual manipulation may supplant either actuator. Here, also, a locking mechanism (e.g., latch, detents, snaps, etc.) may be provided to retain the cup holder in the closed condition, and overcome by the opening actuation force.

In this and throughout the embodiments, a strain relief mechanism70(FIG. 5b) is preferably coupled between the wire14and compartment26(or fixed structure) and presents a secondary work output path when the actuator14is activated and the component12(e.g., cup holder24) is unable to move. For example, an extension spring and mechanically advantageous lever (not shown) may be utilized, as applied in other SMA applications. More preferably, the relief mechanism70also activates a cutoff switch72(FIG. 5b) that interrupts the signal from the power supply and ceases activation of the wire16. Finally, it is appreciated that an input device (e.g., a push button, sliding gauge, wheel, touch screen, microphone, etc.) or sensor74(FIG. 1) may be communicatively coupled to the actuator14, such that when information is received or detected, the actuator14is caused to manipulate the component12.

Ranges disclosed herein are inclusive and combinable (e.g., ranges of “up to about 25 wt %, or, more specifically, about 5 wt % to about 20 wt %”, is inclusive of the endpoints and all intermediate values of the ranges of “about 5 wt % to about 25 wt %,” etc.). “Combination” is inclusive of blends, mixtures, alloys, reaction products, and the like. Furthermore, the terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The modifier “about” used in connection with a quantity is inclusive of the state value and has the meaning dictated by context, (e.g., includes the degree of error associated with measurement of the particular quantity). The suffix “(s)” as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term (e.g., the colorant(s) includes one or more colorants). Reference throughout the specification to “one embodiment”, “another embodiment”, “an embodiment”, and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.