Patent Publication Number: US-2022227315-A1

Title: Vehicle appliques

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a divisional of U.S. patent application Ser. No. 16/426,344 filed May 30, 2019, entitled VEHICLE APPLIQUES, the entire disclosure of which is hereby incorporated herein by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure generally relates to vehicle appliques. More specifically, the present disclosure relates to vehicle appliques with diffraction grating and methods of making the same. 
     BACKGROUND OF THE DISCLOSURE 
     Iridescent components may offer a unique and attractive viewing experience. The iridescent components may upgrade the aesthetics of a vehicle. Typically, to upgrade the aesthetics of the vehicle, molded plastic components are formed to resemble jewels, which are then attached to the vehicle. 
     SUMMARY OF THE DISCLOSURE 
     According to at least one aspect of the present disclosure, a vehicle applique includes a base structure and a polymeric coating disposed on the base structure. The polymeric coating at least partially covers an outer surface of the base structure. A diffraction grating is integrally defined by the polymeric coating. The diffraction grating has a thickness in a range of from about 100 nm to about 300 nm. 
     According to another aspect of the present disclosure, a method of manufacturing a vehicle applique includes providing a mold and selectively etching a first pattern on at least one surface of the mold. A second pattern is selectively nano-engraved on the at least one surface of the mold. The second pattern includes a diffraction grating. A base structure is positioned within the mold. A polyurethane coating is injection molded into the mold. 
     According to another aspect of the present disclosure, a method of manufacturing a vehicle applique including providing a mold and nano-engraving a diffraction grating on a surface of the mold. The surface of the mold is heated via induction heating. A base structure is positioned within the mold. A polymeric coating is injection molded over the base structure. 
     These and other aspects, objects, and features of the present disclosure will be understood and appreciated by those skilled in the art upon studying the following specification, claims, and appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following is a description of the figures in the accompanying drawings. The figures are not necessarily to scale, and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness. 
       In the drawings: 
         FIG. 1  is a front perspective view of a vehicle including appliques, according to one example; 
         FIG. 2  is an enlarged view of a window applique of  FIG. 1 , taken at section II; 
         FIG. 3  is an enlarged view of the applique of  FIG. 2 , taken at section III; 
         FIG. 4  is a cross-sectional view of a diffraction grating of  FIG. 3  taken along line IV-IV; 
         FIG. 5  is an enlarged view of a grille applique of  FIG. 1  taken at section V; 
         FIG. 6  is a cross-sectional view of the grille applique of  FIG. 5  taken along line VI-VI; 
         FIG. 7  is a schematic of a nano-engraving process using a femtosecond ultraviolet laser, according to one example; 
         FIG. 8  is a schematic of heating a mold for making a vehicle applique, according to one example; 
         FIG. 9  is a schematic of an insert molding process for making an applique, according to one example; 
         FIG. 10  is a schematic of a two-shot injection molding process for making a vehicle applique, according to one example; and 
         FIG. 11  is a flow diagram of a method of manufacturing a vehicle applique, according to one example. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Additional features and advantages of the invention will be set forth in the detailed description which follows and will be apparent to those skilled in the art from the description, or recognized by practicing the invention as described in the following description, together with the claims and appended drawings. 
     For purposes of description herein, the terms “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” “horizontal,” and derivatives thereof shall relate to the concepts as oriented in  FIG. 1 . However, it is to be understood that the concepts may assume various alternative orientations, except where expressly specified to the contrary. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     As used herein, the term “and/or,” when used in a list of two or more items, means that any one of the listed items can be employed by itself, or any combination of two or more of the listed items, can be employed. For example, if a composition is described as containing components A, B, and/or C, the composition can contain A alone; B alone; C alone; A and B in combination; A and C in combination; B and C in combination; or A, B, and C in combination. 
     As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. When the term “about” is used in describing a value or an end-point of a range, the disclosure should be understood to include the specific value or end-point referred to. Whether or not a numerical value or end-point of a range in the specification recites “about,” the numerical value or end-point of a range is intended to include two embodiments: one modified by “about,” and one not modified by “about.” It will be further understood that the end-points of each of the ranges are significant both in relation to the other end-point, and independently of the other end-point. 
     The terms “substantial,” “substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a “substantially planar” surface is intended to denote a surface that is planar or approximately planar. Moreover, “substantially” is intended to denote that two values are equal or approximately equal. In some embodiments, “substantially” may denote values within about 10% of each other, such as within about 5% of each other, or within about 2% of each other. 
     As used herein the terms “the,” “a,” or “an,” mean “at least one,” and should not be limited to “only one” unless explicitly indicated to the contrary. Thus, for example, reference to “a component” includes embodiments having two or more such components unless the context clearly indicates otherwise. 
     In this document, relational terms, such as first and second, top and bottom, and the like, are used solely to distinguish one entity or action from another entity or action, without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. 
     Referring to  FIGS. 1-11 , reference numeral  10  generally refers to a vehicle having an applique  14 . The applique  14  includes a base structure  18  and a polymeric coating  22  disposed on the base structure  18 . The polymeric coating  22  at least partially covers an outer surface  26  of the base structure  18 . A diffraction grating  30  is integrally defined by the polymeric coating  22 . The diffraction grating  30  has a thickness in a range of from about 100 nm to about 300 nm. 
     Referring to  FIG. 1 , the vehicle  10  having various appliques  14  is illustrated in one example. The vehicle  10  is a wheeled motor vehicle depicted as a sport utility vehicle, but may also be a sedan, a truck, a van, crossover, or other style of vehicle  10 . The vehicle  10  may be a manually operated vehicle  10  (e.g., with a human driver), a fully autonomous vehicle  10  (e.g., no human driver), or a partially autonomous vehicle  10  (e.g., may be operated with or without a human driver). Additionally, the vehicle  10  may be utilized for personal and/or commercial purposes, such as for ride-providing services (e.g., chauffeuring) and/or ride-sharing services. 
     The vehicle  10  may include a variety of appliques  14  for providing a selected aesthetic for the vehicle  10 . The appliques  14 , as illustrated in  FIG. 1 , may be positioned on an exterior  34  of the vehicle  10  and may also be positioned on an interior of the vehicle  10 . For example, the applique  14  may be a grille applique, an emblem, a wheel applique, a door panel, a pillar feature (e.g., A-, B-, and/or C-pillars), or other trim pieces or appliques  14 . Additionally or alternatively, the applique  14  may be disposed on an interior of the vehicle  10 . For example, the applique  14  may be a steering wheel cover, an infotainment system cover, a dash cover of an instrument panel, or an interior door cover. It will be understood that the foregoing description is exemplary and that other appliques (e.g., center console cover, glove box door, cup holder, interior pillar covers, instrument cluster hood) may be equally applicable to the teachings provided herein. 
     Referring to  FIGS. 1 and 2 , the applique  14  may be formed of the base structure  18  defining one or more surfaces, including an outer surface  26  that may not be directly coupled to the vehicle  10 . The base structure  18  may include, acrylic, polycarbonate (PC), polypropylene, nylon, acrylonitrile styrene acrylate (ASA), polycarbonate acrylonitrile styrene acrtlate (PC ASA), acrylonitrile butadiene styrene, polylactic acid, polyethersulfone, polyethylene, polyvinyl chloride, a liquid crystal polymer, cyclo-olefin copolymer, other thermoplastic materials, thermoset materials and/or combinations thereof. The base structure  18  may be molded to the selected shape depending on the selected applique  14 . 
     The applique  14  may have the polymeric coating  22  disposed on at least one of the surfaces of the base structure  18 . In a specific example, the polymeric coating  22  may partially or entirely cover the outer surface  26  of the base structure  18 . The polymeric coating  22  includes polyurethane, polyuria, or another optically clear polymeric material  22 A. As used herein, the term “optically clear” refers to a material that has a high light transmittance over at least a portion of the visible light spectrum (about 400 nm to about 700 nm) and that exhibits low haze. Both the luminous transmission and the haze can be determined using, for example, the method  200  of ASTM-D 1003-95. In various examples, the polymeric coating  22  has about 10% haze or less, about 5% haze or less, and/or about 2% haze or less. The polymeric coating  22  may be advantageous for providing an optically clear, scratch-resistant coating to protect the base structure  18 . Further, the polymeric coating  22  may be self-healing. As used herein, “self-healing” refers to a material that can automatically and/or intrinsically correct damage without human intervention. The self-healing aspect may be intrinsic and autonomous or may activate in response to an external stimulus (e.g., light  42 , temperature, etc.). The ability to correct damage caused by normal usage may decrease costs and increase the life of the material. 
     Referring to  FIGS. 3 and 4 , the polymeric coating  22  may define the diffraction grating  30 . The diffraction grating  30  extends across the entire polymeric coating  22 , or across discrete portions of the polymeric coating  22 . As illustrated in  FIG. 3 , the diffraction grating  30  may form a pattern  50  in the polymeric coating  22 . However, it is also contemplated that the diffraction grating  30  may not form a pattern  50 , and may instead be random. The diffraction grating  30  may define a variety of patterns  50 . For example, the diffraction grating  30  may include a ruled grating pattern having ridges and grooves. Additionally or alternatively, the diffraction grating  30  may include a holographic grating pattern having a sinusoidal shape. Additionally or alternatively still, the diffraction grating  30  may include a spaced-holographic pattern having alternating plateaus and rounded grooves. The applique  14  may include a single diffraction grating  30 , or more than one diffraction grating. In examples with more than one diffraction grating  30 , the different diffraction gratings  30  may have different properties (e.g., spacing, period  54 , or blaze angle θ B ) which may cause each diffraction grating  30  to diffract light differently (i.e., be noticeably different from one another). 
     The diffraction grating  30  may be distinguished from traditional texturing or ridging of appliques  14  in that traditional texturing or ridging is configured to decrease shine, glare, reflectance and/or optical effects from the appliques  14 , while the diffraction gratings  30  is configured to diffract and scatter light  42  impinging on the applique  14 . The diffraction grating  30  is an optical component with a periodic structure, which splits and diffracts incident light  42  into several beams traveling in different directions. The directions of these beams depend on the spacing of the diffraction grating  30  and the wavelength of the light  42 , so that the diffraction grating  30  acts as the dispersive element. With reference to  FIG. 4 , the diffraction grating  30  is configured to produce an iridescent pattern to light  42  impinging upon it. The diffraction grating  30  may be present on a flat surface, a curved surface, or any other shaped surface. For example, the diffraction grating  30  may be configured to reflect light  42  of different wavelengths in different directions. The diffraction grating  30  may have a thickness  58  of less than or equal to about 700 nm. According to a specific example, the diffraction grating  30  may have a thickness  58  in a range of from about 100 nm to about 300 nm. In another specific example, the diffraction grating  30  may have a thickness  58  of less than or equal to about 200 nm. The thickness  58  of the diffraction grating  30  may affect the optical properties of the applique  14 . As depicted in  FIG. 4 , in an exemplary form, the diffraction grating  30  may define a plurality of ridges  62  having a sawtooth or triangular shape. In three dimensions, the ridges  62  of the diffraction grating  30  can appear with a stepped or sawtooth shape without angular features, pyramidal in shape, or some combination of stepped and pyramidal shapes. In other words, the diffraction grating  30  may include the ruled diffraction grating pattern. Other shapes of the ridges  62  of the diffraction grating  30  include hill-shaped features (e.g., sinusoidal- or curved-shaped features). Stated differently, the diffraction grating  30  may include the holographic and/or spaced-holographic diffraction grating pattern. The diffraction grating  30  can also include portions with a combination of triangular- and hill-shaped ridges. More generally, the shapes of the diffraction grating  30  should be such that an effective blazing angle θ B  of at least 15 degrees is present for one or more portions of each ridge, grating, tooth, or groove of the diffraction grating  30 . The blaze angle θ B  is the angle between step normal (i.e., the direction normal to each step or tooth of the diffraction grating  30 ) and a direction normal  68  to a coating surface  70  having the diffraction grating  30 . 
     Generally, the blaze angle θ B  is optimized to maximize the efficiency of the wavelength(s) of the incident light  42 , which may be typical ambient sunlight or light from a light source, to ensure that maximum optical power is concentrated in one or more diffraction orders while minimizing residual power in other orders (e.g., the zeroth order indicative of the ambient light itself). An advantage of situating the diffraction grating  30  on planar portions or aspects of the surface is that a constant blaze angle θ B  and a period  54  will result in consistent reflected and diffracted light  42   n ,  42   n+1  produced from the diffraction grating  30 . 
     The diffraction grating  30  of the applique  14  may be characterized by one or more periods  54  (also known as d in the standard nomenclature of diffraction grating  30 ). In various aspects of the applique  14 , the period  54  of the diffraction grating  30  is maintained between about 50 nm and about 5 microns. In general, the maximum wavelength that a given diffraction grating  30  can diffract is equal to about twice the period  54 . Hence, a diffraction grating  30  with a period  54  that is maintained between about 50 nm and about 5 microns can diffract light  42   n ,  42   n+1  in an optical range of 100 nm to about 10 microns. According to a specific example, the period  54  of a diffraction grating  30  is maintained from about 150 nm to about 400 nm, ensuring that the diffraction grating  30  can efficiently diffract light  42   n ,  42   n+1  in an optical range of about 300 nm to about 800 nm, roughly covering the visible spectrum. 
     The light  42  at an incident angle α is directed against a sawtooth-shaped diffraction grating  30  having a thickness  58 , a period  54 , and a blaze angle θ B . More particularly, a portion of the light  42  striking the diffraction grating  30  at an incident angle α is reflected as reflected light  42   r  at the same angle α, and the remaining portion of the incident light  42  is diffracted at particular wavelengths corresponding to diffracted light  42   n ,  42   n+1 , etc., at corresponding diffraction angles β n , β n+1 , etc. The reflected light  42   r  is indicative of the zeroth order (i.e., n=0) and the diffracted light  42   n ,  42   n+1  are indicative of the nth order diffraction according to standard diffraction grating terminology, where n is an integer corresponding to particular wavelengths of the reflected or diffracted light  42   r ,  42   n . Additionally or alternatively, diffraction grating  30  may employ varying periods  54  (e.g., as including a set of periods  54 ) that can be employed in iridescent applique  14 . Consequently, the diffraction grating  30  advantageously can produce jewel-like effects of widely varying wavelengths within various regions of the pattern  50 . 
     In some aspects, the diffraction grating  30  includes a varying period  54  that varies between two and ten discrete values or, in specific examples, between two and five discrete values across the diffraction grating  30 . According to another aspect, the diffraction grating  30  with varying periods  54  can be employed in one or more portions of the coating surface  70  of the polymeric coating  22 , and one or more diffraction grating  30  having a constant period  54  are employed in other portions of the polymeric coating  22  to create interesting, jewel-like appearance effects produced by the applique  14  employing the diffraction grating  30 . In another example, the diffraction grating  30  includes a varying period  54  that changes between any number of values, only limited by the overall length of the diffraction grating  30  and/or the processing capabilities to develop such variability through precise control of mold dimensions. In another embodiment, there may be a plurality of diffraction grating  30  in a spaced-apart configuration across the applique  14 . In such an embodiment, the plurality of diffraction grating  30  may have the same or different period  54 . 
     Referring to  FIG. 5 , the diffraction grating  30  may form the pattern  50  across the surface of the applique  14 . The pattern  50  may be symmetrical, repeated, and/or continuous. Alternatively, the pattern  50  may be random. The applique  14  may also include several different patterns. The pattern  50  may be defined by the diffraction grating  30  being selectively applied to the polymeric coating  22 . Accordingly, some portions of the applique  14  may include the diffraction grating  30  and other portions may not include the diffraction grating  30 . Stated differently, the pattern  50  may result in an outline portion  50 A of the pattern  50  including diffraction grating  30 , and a body portion  50 B of the pattern  50  being substantially free of the diffraction grating  30 , 
     With reference to  FIG. 6 , the applique  14  may include the base structure  18  with the polymeric coating  22  disposed thereon. As illustrated, the polymeric coating  22  includes the diffraction grating  30 . Alternatively, the base structure  18  may include the diffraction grating  30  defined by the outer surface  26 . In various aspects, the base structure  18  and the polymeric coating  22  may include the diffraction grating  30 . The diffraction grating(s) on the base structure  18  and the polymeric coating  22  may be the same or different. Having additional patterns of diffraction grating  30  may provide a three-dimensional visual effect to the applique  14 . 
     Referring again to  FIGS. 2-6 , the diffraction grating  30  may define indicia  78 . In various examples, when minimal or no light  42  is directed at the diffraction grating  30 , the indicia  78  may be substantially hidden. In this way, the indicia  78  on the applique  14  may not be visible or may be partially visible. When the light  42  is directed on the applique  14 , the diffraction grating  30  may scatter the light  42  to reveal the indicia  78  on the applique  14 . The indicia  78  may be a pattern  50 , design, logo, lettering, picture, or any other indicia  78 . In various aspects, the diffraction grating  30  in the polymeric coating  22  and/or the base structure  18  may produce a holographic image or other optical effect. 
     Referring now to  FIG. 7 , and with further reference to  FIG. 1-6 , the diffraction grating  30  of the polymeric coating  22  may be formed by nano-engraving a mold pattern  84  onto a cavity surface  86  of a mold  88 . The mold pattern  84  may be selectively nano-engraved onto one or more cavity surfaces  86  of the mold  88 . The mold pattern  84  may be a diffraction grating  30 . The nano-engraving of the mold pattern  84  may be accomplished via a femtosecond ultraviolet laser (a “femto-laser”)  90 . Femto-lasers  90  often include a titanium-sapphire (Ti:sapphire) laser, which may be tunable to emit red and near-infrared light having a wavelength in a range of from about 650 nm to about 1100 nm. The femto-laser  90  generates ultrashort pulses having a duration in a range of from a few picoseconds to about 10 femtoseconds. In a specific example, the femto-laser  90  nano-engraves the cavity surface  86  in pulses having a duration between about 10 femtoseconds and about 15 femtoseconds. The ultrashort duration of the pulses operates to obliterate and/or remove a few molecules of the cavity surface  86  during each pulse. Accordingly, the femto-laser  90  may not produce a heat-affected zone of the cavity surface  86 . The short interaction between the femto-laser  90  and the mold  88  may allow the electrons within affected molecules to be heated without heating other molecules. Further, the femto-laser  90  may nano-engrave ultra-fine details in the cavity surface  86  of the mold  88 . Accordingly, the femto-laser  90  can provide nano-engravings  82  that are as thin as about 100 nm in thickness  58 . Moreover, the femto-laser  90  may operate at a peak power of about 15 GW, which can cause multi-photon ionization (MPI). The intensity of the femto-laser  90  pulsing initiating the mulita-photon effect may allow for the engraving of solid materials used in tooling (e.g., the mold  88 ). Additionally or alternatively, the femto-laser  90  may nano-engrave complex surfaces. In a specific aspect, the use of the femto-laser  90  may be advantageous for providing a pattern  50  on a grille applique  14  that includes complex surfaces ( FIGS. 5 and 6 ). 
     An etching may also be selectively applied to the cavity surface  86  of the mold  88  by the femto-laser  90  or a separate laser. In various examples, a picosecond or nanosecond YAG laser may be used in conjunction with the Ti:sapphire laser. The YAG laser can remove more material from the mold  88  to produce a rough finishing of the cavity surface  86 , while the Ti:sapphire laser may provide the more minute diffraction gratings  30 . Alternatively, the femto-laser  90  (e.g., the Ti:sapphire laser) may provide the entire pattern  50  on the cavity surface  86 . 
     With reference to  FIG. 8 , the mold  88  may be heated via induction heating. Heating elements  92  may be disposed behind the cavity surface  86  of the mold  88  for heating the cavity surface  86 . In various examples, the cavity surface  86  of the mold  88  may be heated to the melting point of the polymeric material  22 A included in the polymeric coating  22 . Heating the cavity surface  86  having the etchings and/or nano-engravings  82  may retain the polymeric material  22 A in liquid form and/or with a low viscosity to fill the details of the etchings and/or nano-engravings  82 . It is also contemplated that the mold  88  may be heated by steam or hot oil. 
     Referring to  FIG. 9 , molding of the base structure  18  and the addition of the polymeric coating  22  may be accomplished in a single mold  88  (e.g., a single tool). The mold  88  may be heated and the base material  18 A may be injected into a first cavity  98  of the mold  88 . The base structure  18  may then be molded into the selected shape for the applique  14 . Once the base structure  18  is molded and cooled, the mold  88  is opened and the polymeric material  22 A of the polymeric coating  22  can be injected over the base structure  18  within the first cavity  98 . Once the polymeric coating  22  has cured, the mold  88  is opened and the applique  14  may be removed. 
     Alternatively, referring to  FIG. 10 , the applique  14  may be formed through a two-shot injection molding process  114 . The two-shot injection molding process  114  may be advantageous for a higher volume of production. In a step  114 A of the two-shot injection molding process  114 , the base material  18 A for the base structure  18  may be injected into a first cavity  98  of the mold  88 . In a step  114 B, the mold  88  may maintain pressure, allowing the base structure  18  to cool into the selected shape for the applique  14 . In a step  114 C, the mold  88  may be opened and a swivel plate  94  may be rotated about 180°, such that the base structure  18  is disposed within a second cavity  102  of the mold  88 . Once rotated, in a step  114 D, the mold  88  may close again and the polymeric material  22 A polymeric coating  22  may be injected into the second cavity  102  over the base structure  18 . Simultaneously, or about simultaneously, the base material  18 A for the base structure  18  for the next applique  14  produced is injected into the first cavity  98  of the mold  88 . In a step  114 E, the mold  88  may hold pressure, allowing for the polymeric coating  22  to cure and the base structure  18  to cool. In a step  114 F, the mold  88  may then be reopened and the applique  14  (the combined base structure  18  and polymeric coating  22 ) may be removed, and the swivel plate  94  may rotate about 180° for the cycle to repeat (e.g., begin again at step  114 A). 
     Referring to  FIG. 11 , and with further reference to  FIGS. 1-10 , a method  200  of manufacturing the applique  14  includes a step  204  of providing a mold  88 . The mold  88  may be utilized in overmolding the polymeric coating  22  onto the base structure  18  or, alternatively, for two-shot injection molding process  114 . 
     The method  200  includes a next step  208  of molding the base structure  18 . The base structure  18  may be molded into the grille applique, the pillar feature, the emblem, or any of the other style appliques  14 , as discussed previously herein. The base structure  18  may be molded in a same cavity of the mold  88  or a separate cavity relative to the polymeric coating  22 . Accordingly, the base structure  18  may define a diffraction grating  30 . Alternatively, the base structure  18  may not define the diffraction grating  30 . 
     A next step  212  of the method  200  may include etching the cavity surface  86  of the mold  88 . The etching may be accomplished with a YAG laser or within a Ti:sapphire laser (e.g., the femto-laser  90 ). The etching may provide a first pattern  106  on the cavity surface  86 . The first pattern  106  may or may not include diffraction grating  30 . The etching may be selectively applied to the cavity surface  86 , such that the first pattern  106  is provided on a first portion  108  of the cavity surface  86  and leaves a second portion  112  of the cavity surface  86  substantially free of the diffraction grating  30 . The etching may be provided on one or more surfaces of the mold  88 . 
     Next, a step  216  includes nano-engraving  82  a second pattern  110  on the cavity surface  86  of the mold  88 . The nano-engraving  82  may produce the second pattern  110  including the diffraction grating  30  on the cavity surface  86 . The nano-engraving  82  may be accomplished with the femto-laser  90 , which may be advantageous for providing minute details for the diffraction grating  30 . In a specific example, the nano-engravings  82  may have a depth in the cavity surface  86  in a range of about 100 nm to 300 nm. In another specific example, the nano-engravings  82  may have a depth about or less than 200 nm. Accordingly, the nano-engravings  82  may produce a diffraction grating  30  having a thickness  58  in a range of from about 100 nm to about 300 nm, or about or less than 200 nm, accordingly. The nano-engravings  82  may be applied to the first portion  108  of the cavity surface  86 , the second portion  112  of the cavity surface  86 , and/or a combination thereof. 
     A step  220  includes heating the mold  88 . As previously explained with reference to  FIG. 8 , the cavity surface  86  may be heated via induction heating by the heating elements  92 . The heating of the cavity surface  86  having the etchings and/or nano-engravings  82  allows for the material of the polymeric coating  22  to remain highly viscous and fill the minute details of the first and second patterns  106 ,  110  (e.g., the diffraction grating  30 ) in the cavity surface  86 . 
     In a step  224 , the base structure  18  is positioned within the mold  88 . The base structure  18  may be disposed within the mold  88  from when the base structure  18  was molded, as in the step  224 , or may be formed separately and later disposed within the mold  88 . The step  224  may also include cooling the base structure  18 , such that the base structure  18  may retain its shape when the mold  88  is opened. 
     Next, in a step  228 , the polymeric coating  22  is injected over the base structure  18 . As previously explained with respect to  FIG. 9 , the polymeric coating  22  may be molded over the base structure  18  after the base structure  18  is molded. Alternatively, as previously discussed with respect to  FIG. 10 , the polymeric coating  22  may be injected over the base structure  18  in the two-shot injection molding  114  process. The polymeric coating  22  may remain viscous, at least in part due to the heated mold  88  and/or cavity surface  86  of the mold  88 . In various examples, the material of the polymeric coating  22  may be in liquid form under normal conditions (e.g., pressure, temperature, etc.). As such, the liquid material may be viscous with or without the heated mold  88 . The polymeric coating  22  may flow over the base structure  18  and fill the etchings and/or nano-engravings  82  of the cavity surface  86 . Accordingly, the mold pattern  84  and/or the etchings and/or nano-engravings  82  in the cavity surface  86  may be a mirror image of the selected diffraction grating  30  or pattern  50  to be integrally defined by the polymeric coating  22 . The polymeric coating  22  including polyurethane and/or polyuria may be advantageous for defining the diffraction grating  30  nano-engraved by the femto-laser  90 . The step  228  may also include the polymeric coating  22  curing, and the applique  14  being removed from the mold  88 . 
     Use of the present disclosure may provide for a variety of advantages. For example, the use of the femto-laser  90  may provide for minute nano-engravings  82  that may not be attainable with a conventional laser. Further, the femto-laser  90  may provide nano-engravings  82  with minute details to provide for a variety of patterns  50 . Moreover, the femto-laser  90  may operate in ultra-short pulses with higher power, which may allow a variety of surfaces, including the cavity surface  86  of a mold  88  or other tooling, to be nano-engraved. The diffraction grating  30  formed by the femto-laser  90  may be substantially hidden when minimal or no light  42  is directed at the applique  14 . When light  42  is directed at the applique  14 , the diffraction grating  30  may diffract the light  42  to reveal the pattern  50  on the applique  14 . Moreover, the diffraction grating  30  may be applied to base structures  18  that have complex surfaces, which may not be accomplished with a conventional laser. The polymeric coating  22  may provide durability for the applique  14 . The polymeric coating  22  may be scratch-resistant and ultraviolet (UV) resistant and may prevent weathering of the applique  14 , thereby increasing the lifetime of the applique  14 . Additionally, the polymeric coating  22  may have a more aesthetically appealing design than conventional painted appliques, as conventional painted appliques may have an orange peel that may prevent the selected appearance. 
     According to various examples, a vehicle applique includes a base structure and a polymeric coating disposed on the base structure. The polymeric coating at least partially covers an outer surface of the base structure. A diffraction grating is integrally defined by the polymeric coating. The diffraction grating has a thickness in a range of from about 100 nm to about 300 nm. Embodiments of the present disclosure may include one and/or a combination of the following features:
         a polymeric coating includes at least one of polyurethane and polyuria;   a diffraction grating has a period in a range of from about 50 nm to about 5 microns;   a diffraction grating has a period in a range of from about 150 nm to about 400 nm;   a diffraction grating defines indicia;   a diffraction grating includes a ruled grating pattern; and   a diffraction grating includes a holographic grating pattern.   According to various examples, a method of manufacturing a vehicle applique includes providing a mold and selectively etching a first pattern on at least one surface of the mold. A second pattern is selectively nano-engraved on the at least one surface of the mold. The second pattern includes a diffraction grating. A base structure is positioned within the mold. A polyurethane coating is injection molded into the mold. Embodiments of the present disclosure may include one or a combination of the following features:   heating a mold to a melting point of a polyurethane coating;   a femtosecond ultraviolet laser forms a nano-engraved second pattern;   selective nano-engraving occurs in pulses having a duration between about 10 femtoseconds and about 15 femtoseconds;   selective nano-engraving produces the diffraction grating having a thickness of less than about 700 nm;   selective nano-engraving produces the diffraction grating has a thickness of less than about 200 nm;   molding a base structure into a pillar feature for a vehicle; and   molding a base structure into a vehicle grille.       

     According to various examples, a method of manufacturing a vehicle applique including providing a mold and nano-engraving a diffraction grating on a surface of the mold. The surface of the mold is heated via induction heating. A base structure is positioned within the mold. A polymeric coating is injection molded over the base structure. Embodiments of the present disclosure may include one or a combination of the following features:
         selective nano-engraving provides a diffraction grating on a first portion of a mold and leaves a second portion of a mold substantially free of the diffraction grating;   a surface of a mold is heated to a melting point of a polymeric coating;   a femtosecond ultraviolet laser forms a nano-engraved diffraction grating; and   nano-engraving produces a diffraction grating having a thickness of less than about 700 nm.       

     Modifications of the disclosure will occur to those skilled in the art and to those who make or use the disclosure. Therefore, it is understood that the embodiments shown in the drawings and described above are merely for illustrative purposes and not intended to limit the scope of the disclosure, which is defined by the following claims, as interpreted according to the principles of patent law, including the doctrine of equivalents. 
     It is to be understood that variations and modifications can be made on the aforementioned structure without departing from the concepts of the present disclosure, and further it is to be understood that such concepts are intended to be covered by the following claims unless these claims by their language expressly state otherwise.