PHOTONIC STRUCTURE FOR THE DYNAMIC EXPRESSION OF COLORS AND EFFECTS

Abstract

PHOTONIC STRUCTURE FOR THE DYNAMIC EXPRESSION OF COLOURS AND EFFECTS A photochromic formulation comprises a core material and a photochromic layer covering the core material and forming a particle.The photochromic layer may comprise a plurality of photochromic materials, including a first photoreactive pigment characterized by a reversible diffuse reflectance at a first central wavelength in response to irradiation by photons of a first characteristic wavelength, a second photoreactive pigment characterized by a reversible diffuse reflectance at a second central wavelength in response to irradiation by photons of a second characteristic wavelength, and a third photoreactive pigment characterized by a reversible diffuse reflectance at a third central wavelength and a fourth central wavelength in response to irradiation by photons of a third characteristic wavelength. Figure for the abstract: 1.

Description

Title of the invention: PHOTONIC STRUCTURE FOR THE DYNAMIC EXPRESSION OF COLORS AND EFFECTS SUMMARY

[0001] Methods, systems, and materials for an integrated photochromic cosmetic application are described. A photochromic formulation may be or comprise a core material and a photochromic layer covering the core material and forming a particle centered around the core material.

[0002] In certain embodiments, the photochromic layer may be or comprise a plurality of photochromic materials, comprising a first photoreactive pigment characterized by a reversible diffuse reflectance at a first central wavelength of 490 nm to 520 nm in response to irradiation by photons of a first characteristic wavelength. The photochromic layer may comprise a second photoreactive pigment characterized by a reversible diffuse reflectance at a second central wavelength of 570 nm to 590 nm in response to irradiation by photons of a second characteristic wavelength.The photochromic layer may also include a third photoreactive pigment characterized by a reversible diffuse reflectance at a third central wavelength of 450 nm to 495 nm and a fourth central wavelength of 625 nm to 740 nm in response to irradiation by photons of a third characteristic wavelength. The first characteristic wavelength, the second characteristic wavelength, and the third characteristic wavelength may be the same or different.

[0003] In certain embodiments, the first photoreactive pigment may be or comprise 1,2-bis(2-methyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluorocyclopentene. The second photoreactive pigment may be or comprise 1,2-bis(2-methyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluorocyclopentene. The third photoreactive pigment may be or comprise 1,2-bis(3-methylbenzo(b)thiophen-2-yl)perfluorocyclopentene. The photochromic layer may be or comprise spiropyranes, spirooxazines, diarylethenes, azobenzenes, quinones, silver halides, or zinc halides. The photochromic layer may be or include DAE-0001, DAE-0012 and DAE-0068.

[0004] In certain embodiments, the central material may be or comprise a reflective mineral. The reflective mineral may be or comprise mica, titanium oxide, or silicon oxide. The photochromic formulation may further comprise a shimmer-regulating layer interposed between the The core material and the photochromic layer comprise a photoreactive material characterized by a transition from visible transparency to visible opacity when exposed to irradiation of a characteristic wavelength, the visible opacity corresponding to a broad reflectance in the visible spectrum. The transition from visible transparency to visible opacity may be gradual, proportional to the intensity of the irradiation. The particle may have a diameter of 20 micrometers or less.

[0005] A photochromic formulation may be or comprise a core material and a structural color material covering the core material forming a particle centered around the core material.

[0006] In certain embodiments, the structural color material may be or comprise a photonic crystal material. The photonic crystal material may be or comprise a first photonic crystal material characterized by a first structural color in the bluish range. The photonic crystal material may be or comprise a second photonic crystal material characterized by a second structural color in the greenish range. The photonic crystal material may be or comprise a third photonic crystal material characterized by a third structural color in the reddish range. The photochromic formulation may further comprise a plurality of particles including the particle. The plurality of particles may include a first proportion of particles comprising the first nanostructured material.The plurality of particles may include a second proportion of particles comprising the second nanostructured material. The plurality of particles may also include a third proportion of particles comprising the third nanostructured material. The first proportion, the second proportion, and the third proportion may be substantially equal or disparate.

[0007] In certain embodiments, the structural color material may further comprise a photoreactive matrix characterized by a transition from visible transparency to visible opacity when exposed to irradiation at a characteristic wavelength associated with the respective structural color. The nanostructured material may be or comprise a plurality of porous clusters suspended in the photoreactive matrix. The porous clusters may be or comprise an inverse opal formed from silicon oxide or titanium oxide. The photochromic formulation may also comprise a luminosity layer covering the photochromic layer. The luminosity layer comprises a photoreactive material characterized by a transition from visible transparency to visible opacity when exposed to irradiation at a characteristic wavelength, the visible opacity corresponding to a broad absorbance in the visible spectrum.The transition from visible transparency to visible opacity can be progressive and proportional. The irradiation level is important. The brightness layer may be or contain spiropyran or naphthopyran. The core material and the structural color material may be the same or different materials.

[0008] This summary is provided to present a selection of concepts in a simplified form, which are described in more detail below in the detailed description. This summary is not intended to identify key features of the claimed subject matter, nor to be used as an aid in determining the scope of the claimed subject matter. BRIEF DESCRIPTION OF THE FIGURES

[0009] [Fig.1] Fig.1 is a schematic illustration of an embodiment of a system incorporating sensors and an illumination source for the application of cosmetic designs, in accordance with various embodiments.

[0010] [Fig.2A] The [Fig.2A] is a schematic illustration of a digital representation of a cosmetic design in the form of a polygonal grid comprising a design data tensor in a front direction and a small angle direction, in accordance with various embodiments.

[0011] [Fig.2B] The [Fig.2B] is a schematic illustration of a three-dimensional model projection of the cosmetic design onto a face map collected using the system of the [Fig.1], in accordance with various embodiments.

[0012] [Fig.3] The [Fig.3] is a schematic illustration of a photochromic formulation comprising a core-envelope structure, in accordance with various embodiments.

[0013] [Fig.4A] The [Fig.4A] is a schematic illustration of photo-modulation of the photochromic formulation of the [Fig.3], in accordance with various embodiments.

[0014] [Fig.4B] The [Fig.4B] describes spectroscopic aspects of the system of the [Fig.1], in particular intensity spectra and absorbance spectra for three illumination sources and three photochromic materials, in accordance with various embodiments.

[0015] [Fig.5] The [Fig.5] is a schematic illustration of a cosmetic formulation under front illumination and under small angle illumination to produce polychrome designs, in accordance with various embodiments.

[0016] [Fig.6] The [Fig.6] is a flowchart which illustrates an example of a process for applying a cosmetic design using the photochromic material of the [Fig.3], in accordance with various embodiments.

[0017] [Fig.7] Fig.7 is a functional diagram that illustrates aspects of a device appropriate illustrative computer model to be used as a computer device for this disclosure.

[0018] The foregoing aspects and many related benefits of this disclosure will be more readily appreciated as they are better understood with reference to the following detailed description, taken together with the accompanying drawings.

[0019] In the aforementioned drawings, identical numerals refer to identical parts in the different views, unless otherwise indicated. Not all instances of an element are necessarily marked in order to simplify the drawings, where appropriate. The drawings are not necessarily to scale, the emphasis being rather on illustrating the principles described. DETAILED DESCRIPTION

[0020] Applying cosmetics and makeup in patterns and shapes can be difficult by hand. For example, complex designs and theatrical makeup are typically applied by certified professional makeup artists. Furthermore, self-application can be challenging for people with reduced mobility. Currently, solutions are being explored through the development of handheld tools, such as cartridge and dispenser solutions, which implement light-activated, hand-guided cosmetics. While these represent a technological alternative to brushes, these tools are limited by cartridge size, cleaning processes, the inability to mix or blend colors, short battery life, and the lack of tracking. Moreover, by relying on a handheld device, these tools do not address accessibility issues.

[0021] Photochromic formulations are described for applying a cosmetic design to a body surface, such as a subject's face or another area of ​​interest, using one or more light sources. The described embodiments use photoreactive materials in combination with reflective and / or structural color materials to define one or more mapped exposure patterns on the body surface using a projection of the cosmetic design onto a 3D map of the body surface. The described embodiments are useful in many contexts, including cosmetic or body art applications, mapping or monitoring skin features, dermatological diagnosis or treatment, or remote health applications.In the context of such applications, the described embodiments offer greater accuracy and ease of use than complex manual routines.

[0022] In the described embodiments, a photochromic formulation may comprise a micrometer-scale particulate material consisting of several layers. Each layer can individually modulate a color or effect Cosmetics, including but not limited to shimmer, gloss, brightness, angular color, luminescence, iridescence, or fluorescence. Each layer can be activated / modulated / addressed by one or more wavelengths, within the scope of cosmetic design applications, both in terms of color fidelity and cosmetic effects. As an illustrative example, a micrometer-scale particle of the photochromic formulation might include a reflective core containing mica or titanium oxide, a brightness-regulating layer containing a photoreactive material that transitions from transparency to opacity under a specific wavelength, and a color layer comprising four photochromic materials. The photochromic materials can be individually addressed by four different and distinct wavelengths.In this way, a region of the body surface can be exposed to a combination of the four wavelengths to express a single color, for example, as is used in CMYK pigment systems. By applying the photochromic formulation to the body surface, for example in the form of a powder or face cream, exposing the body surface (and therefore the photochromic formulation) to a light source according to an exposure pattern can transfer the design without contact.

[0023] Without being limited to a specific system or method, systems and methods for applying such cosmetic designs are also described in the context of a sensor-carrying system. Sensors suitable for use in the described embodiments include two-dimensional (2D) or three-dimensional (3D) cameras, proximity sensors, or other integrated or peripheral cameras or sensors. Depth sensors are used in some embodiments to obtain 3D information about surfaces and include a range of possible hardware suitable for this purpose, including RGB or infrared stereoscopic cameras, infrared laser or LiDAR sensors, and dot projectors.3D scanning devices enable improved measurement of the true dimensions of a body surface and depth detection, which can help determine, for example, the distance between the body surface and the camera, or detailed information about skin features, such as fine lines. Reference points obtained by high-quality 3D scanning according to the described embodiments offer greater accuracy for determining location than traditional reference points obtained by 2D imaging, such as the eyes, lips, nose, or other prominent facial features, and are particularly useful when the region of interest is obscured.

[0024] The systems described expose the surface to multiple actuation wavelengths in accordance with the cosmetic design as mapped based on 3D information collected by sensors. In this way, the photochromic formulation, applied to a region of the body surface, can be made to accurately and precisely reproduce the cosmetic design through illumination with actuation wavelengths rather than through manual application of cosmetics. Advantageously, the materials, systems, and processes described also offer improved accessibility for users with limited mobility or dexterity, for whom the application of cosmetics, such as makeup, may require assistance. Another advantage is that the materials, systems, and processes described also allow a user to develop, try, or experiment with multiple cosmetic designs without removing or altering the photochromic formulation.For example, in some embodiments, the photochromic formulation can be reset using the same actuation wavelengths as those used to apply the design, allowing for the application of a different cosmetic design. Such versatility reduces the number of materials and layers applied for each design, and further simplifies the cosmetic application.

[0025] Figure 1 is a schematic illustration of an example of a system 100 incorporating sensors and an illumination source for applying cosmetic designs, according to various embodiments. While the embodiments of the photochromic material described with reference to the following figures are illustrated in the context of the example system 100, other approaches are also considered. System 100 is not intended to be the only system for use with the photochromic materials described below.

[0026] In the example system 100, one or more cameras 150 of a client computing device 104 include one or more cameras and capture images of a subject's face 102. In the example shown, the client computing device 104 is a specially designed mobile computing device comprising a mirror for visible light 106, one or more illumination sources 108, and one or more user interface elements 110 for prompting the subject with visual and / or auditory cues. For example, the interface elements 110 may be or include a display electronically coupled to the computer system to generate a visual prompt (e.g., "please turn your face forward") or a device physically coupled to the mirror 106. Alternatively, the client computing device 104 may be electronically coupled to a loudspeaker to generate an auditory prompt.

[0027] The mirror 106 may comprise one or more portions 112 characterized by unidirectional transparency, for example, in the ultraviolet, visible and / or infrared spectral ranges. The camera(s) 150 may be coupled Optically coupled to the visible light mirror 106 is used to receive visible light via a first portion 112-1, and the illumination source(s) 108 can be optically coupled to the visible light mirror 106 and configured to emit a plurality of distinct wavelength channels via a second portion 112-2 of the mirror 106. In this way, the mirror 106 can appear uniform, and the system 100 can aesthetically resemble an ordinary cosmetic mirror with no external indication that the system 100 incorporates electronics, cameras 150, or illumination sources 108. For example, the components of the customer computing device 104 can be integrated into a housing 114 that resembles a consumer cosmetic mirror rather than an electronic system. In this example, the housing 114 can conceal power supplies, heat management systems, and other components.

[0028] While the client computing device 104 is illustrated in a particular configuration (for example, as a countertop mirror or vanity mirror), additional and / or alternative form factors are envisaged. For example, the system 100 may include a smartphone or tablet computer communicating with the client computing device 104, such that one or more computer-executable operations are performed by the smartphone or tablet computer rather than by the client computing device 104. In this way, the client computing device 104 may be or include smaller enclosures 114, including, but not limited to, a cosmetic compact or an electronic device configured to pair electronically with a smartphone or tablet computer that includes the camera 150, the illumination source 108, or both.Similarly, the mirror 106 may be or include a full-length wall mirror, so that the client computer device 104, the camera(s) 150 and the light source(s) 108 can be positioned behind the mirror 106 and one or more portions 112 can be located relative to the camera(s) 150 and the light source(s) 108. In such a configuration, the system 100 can be installed as a fixed device, rather than as a portable system, and a single mirror 106 can be configured to conceal multiple client computer devices 104, multiple cameras 150 and multiple light sources 108, corresponding to a number of 'makeup stations', as in a makeup salon or caravan.

[0029] The illumination source 108 may include one or more optics configured to form a beam and to scan the beam. The optics may include lenses or mirrors internal to the housing 114 that may be actuated or otherwise controlled to direct a beam from the illumination source(s) 108 towards the subject's face 102 and / or the region of interest 120. By For example, the illumination source 108 may be or include one or more laser sources corresponding to the plurality of distinct wavelength channels, as described in more detail with reference to [Fig. 4B], below. In some embodiments, the illumination source 108 includes multiple light-emitting diodes corresponding to the plurality of distinct wavelength channels. Similarly, the illumination source may be or include a continuous source (for example, a tungsten halide or broad-spectrum source) and a plurality of bandpass filters to generate the distinct wavelength channels used by the system 100 to apply a cosmetic design.

[0030] The client computing device 104 can communicate electronically with additional systems via a network or near-field communication protocols (e.g., Wi-Fi, Bluetooth, etc.). For example, the client computing device 104 can pair with a personal electronic device, such as a smartphone or tablet, from which the client computing device 104 can receive an identifier for a drawing, selected, for example, through a browser environment displayed on a smartphone. Similarly, the client computing device 104 can communicate with a server storing digital representations of drawings and can access the drawing from the server.The server can be a remote server or a local server, the terms "remote" and "local" being used both to refer to physical proximity to the system 100 and to indicate whether the client computing device 104 and the server are configured to communicate over a public network, such as the Internet or a distributed network system (e.g., a cloud system). In some cases, the client computing device 104 can store drawing data locally for a number of cosmetic drawings, for example, using non-transient, machine-readable storage media (e.g., SSD flash memory, hard drives, etc.).For example, the client computing device 104 can receive newly published cosmetic design data and associated metadata from the server, such as identifier information and interface data (e.g., images representing the cosmetic design on a model), which can be provided via interface elements 110 or via the mobile electronic device. In such cases, the system can be configured to operate with intermittent or no network connectivity.

[0031] In certain embodiments, the camera 150 acts as a far-field camera positioned and configured to capture video or still images of the subject's face 102, as well as the region of interest 120 of the subject's face 102, such that the region of interest 120 lies within the field of view 152 of the camera unit 150. In the example shown, the region of interest 120 is shown as a portion of the left cheek of the subject's face 102, but the region of interest 120 can cover a larger portion of the subject's face 102, or even the entire face 102. In some embodiments, the camera unit 150 includes more than one camera, for example, for capturing stereoscopic images or videos and / or for depth sensing. In some embodiments, the camera unit 150 also includes one or more sensors other than cameras (for example, a LiDAR sensor or an infrared dot projector for depth sensing, a proximity sensor for proximity sensing, etc.). In some embodiments, an infrared dot projector projects infrared dots onto a surface, and the reflections from the surface are measured by an infrared camera to determine the distance between each dot and the projection system.When combined with a 3D camera, these depth measurements can be represented on a captured 3D image. This approach is used in some embodiments to generate a 3D model of a body surface, and for the real-time tracking of additional features to be used for mapping a cosmetic design onto the subject's face or other body parts.

[0032] Figure [2A] is a schematic illustration of a digital representation of an example cosmetic design 200 in the form of a polygonal grid comprising a design data tensor in a front direction and a small-angle direction, according to various aspects of this disclosure. The design 200 represents an example of visualization of a cosmetic design, comprising multiple polygons 202, where each polygon 202 represents a unit of the digital representation, similar to a pixel in a digital image. When the system implementing the processes described herein (for example, system 100 of [Fig. 1]) can project the design 200 onto a map of the surface of a user's face (for example, the face 102 of the subject of [Fig. 1]), the system can project the design 200 onto a map of the surface of a user's face (for example, the face 102 of the subject of [Fig. 1]).l]), the 202 polygons can be or include triangles or other shapes which offer greater flexibility for surface projection and mapping compared to square or rectangular pixels.

[0033] As shown, a first polygon 202-1 of drawing 200, referenced Celljj in the ij plane of the digital representation, can include multiple types of drawing data corresponding to different layers of drawing 200. For example, the drawing data for the first polygon 202-1 can include, but is not limited to, a front color tuple and a small-angle color tuple, indicating two different colors to be generated by the system 100 at different angles. Each tuple can include color level information corresponding to the photoreactive materials incorporated in a photochromatic formulation. For example, the A photochromatic formulation can include one, two, three, four, or five different photoreactive materials.

[0034] By selectively modulating the photosensitive materials according to the color levels for each polygon, the cosmetic design 200 can be applied to the user. As described in more detail with reference to [Fig. 5], angle-dependent color can be provided using angular illumination, so that a cosmetic design can include iridescence or other angular color effects. While each polygon 202 is shown with a uniform characteristic size, it is understood that the polygons represent a color data tensor that is referenced by cell inputs in ij space, rather than in Cartesian coordinates.In this way, the first polygon 202-1 can be larger or smaller than neighboring polygons 202 when projected into a physical dimension, for example when applied to a user's facial map for the application of cosmetic drawing 200 (e.g., the region of interest 120 of the subject's face 102 in [Fig. 1]).

[0035] Figure 2B is a schematic illustration of an example of a three-dimensional projection 210 of the cosmetic design 200 onto a face map collected using the system of Figure 1, according to various embodiments. As described in more detail with reference to Figure 1, the system 100 is configured to receive the cosmetic design 200 and to generate an exposure pattern. As part of the operations of the system 100, the cosmetic design 200 can be projected onto a 3D map of the user's body portion (for example, the subject's face 102 or the region of interest 120 of Figure 1). The 3D model has several reference points 212 in the form of corresponding triangles (although other polygon shapes are also envisaged) of a grid structure.

[0036] The generation of the 3D projection 210 may involve multiple computer calculation operations to generate a digital representation of a portion of the user's face using the camera (e.g., a facial map). The camera may be or include several image sensors configured to capture stereoscopic images. In this way, the digital representation of the facial portion may be or include a position information tensor defining a surface of the face (e.g., in the region of interest 120 of [Fig. 1]). Examples of computer calculation techniques include edge detection, feature or point detection and tracking, and / or point cloud processes.For example, the 100 system can be configured with a time-of-flight camera, with LiDAR systems, or with stereoscopic cameras, so that facial mapping can represent a surface generated by contours connecting edges, points, and / or features. In some embodiments, . System 100 may include a machine learning implementation, such as a face detection / mapping module that can be trained to predict facial mapping based on a subset of features and / or points measured by the camera. In this way, System 100 can be configured to reduce the number of measurements used to generate the map, which can improve system performance, for example, by reducing the time required to capture images of the user's face.

[0037] Other adaptations can be made for variations in lighting conditions, viewing angles, or other factors. For example, a light sensor mounted on the client computer device 104 can be used to measure current lighting conditions relative to a baseline lighting condition. If the environment is too bright or too dark, the client computer device 104 can generate a prompt to increase the illumination and / or can activate an illumination source (for example, the illumination source 108 in [Fig. 1]) which may or may not be visible to the subject (for example, an infrared source to provide invisible illumination). In one embodiment, the client computer device 104 can provide feedback to a user (for example, via synthesized voice cues or visual cues) to adjust the lighting conditions to obtain better results.In some embodiments, the system can generate feedback to prompt the user to reposition themselves relative to the camera(s) (for example, by generating a prompt to reposition the user's face from a front-facing to a profile position). It should be understood that the described embodiments can be implemented in many possible ways to determine matches between captured image data and texture data in a 3D model, including the matching of detected edges or contours, color / pixel values, depth information, or similar data in different combinations, and at specific confidence threshold levels, each of which can be adjusted based on lighting conditions, user preferences, system design constraints, or other factors.

[0038] The 210 projection can reduce artifacts from applying the design to the face. For example, the polygons into which the 200 design is divided can be scaled heterogeneously, skewed, or otherwise modified during the generation of the 210 projection, as illustrated. For example, while the cosmetic design can be described with each polygon having a uniform size, the 210 projection can have many different sizes for the 212 polygons. In some embodiments, the resizing can match the contours of the face map, where the regions have a high dynamic range. These correspond to smaller 212 polygons, and regions with low dynamic range correspond to larger 212 polygons. Furthermore, and / or alternatively, the 210 projection can be resized according to the information density. For example, when the number of 202 polygons composing the 200 drawing corresponds to the drawing's resolution, analogous to the pixel resolution of a digital image, information-rich regions of the 200 drawing can contain a relatively high number of 202 polygons compared to regions with negligible drawing information. As an illustrative example, more polygons can be used to describe regions around facial features, such as the eyes, nose, mouth, or eyebrows, as opposed to regions of the cheeks, jaw, forehead, etc.In this way, the 210 projection can include exposure data both for a frontal direction (e.g., substantially normal to the surface) and for a small-angle direction, as defined for one or more angles of the user's face relative to the light source. In this context, "substantially" refers to a range of ±20% of the stated value.

[0039] The exposure data illustrated in [Fig. 2B] can be generated by taking into account the intensity values ​​of each color channel included in drawing 200, as well as the exposure data for the photoreactive materials. For example, the color mixing for a first polygon 212-1, as indicated by the intensity data of drawing 200, can be carried out by exposing the first polygon to multiple channels of distinct wavelengths (e.g., for different durations). The physical mechanisms of photochromatic materials are dynamic and can sometimes involve reversible activation / deactivation, so that several drawings 200 can be applied using a single application of photoreactive material. In some embodiments, a "wiping" operation can be implemented by exposing the matrix to a neutralizing wavelength.

[0040] The 210 projection can reduce artifacts from applying the design to the face. For example, the polygons into which the 200 design is divided can be scaled heterogeneously, skewed, or otherwise modified during the generation of the 210 projection, as illustrated. For example, while the cosmetic design can be described with each polygon having a uniform size, the 210 projection can have many different sizes for the 212 polygons. In some embodiments, the resizing can match the contours of the face map, where regions with a high dynamic range correspond to smaller 212 polygons and regions with a low dynamic range correspond to larger 212 polygons. Furthermore and / or alternatively, the The 210 projection can be resized according to the information density. For example, when the number of polygons (202) composing the drawing (200) corresponds to the drawing's resolution, analogous to the pixel resolution of a digital image, information-rich regions of the drawing (200) can contain a relatively high number of polygons (202) compared to regions with negligible drawing information. As an illustrative example, more polygons can be used to describe regions around facial features, such as the eyes, nose, mouth, or eyebrows, as opposed to regions of the cheeks, jaw, forehead, etc.In this way, the 210 projection can include exposure data both for a front direction (e.g., substantially normal to the surface) and for a small-angle direction, as defined for one or more angles of the user's face relative to the illumination source, using a dynamic grid that takes into account surface features.

[0041] Figure 3 is a schematic illustration of an example of a photochromic formulation 300 comprising a core-shell structure, in accordance with various embodiments. The example of the photochromic formulation 300 comprises multiple layers to facilitate the individual modulation / actuation of different elements of a cosmetic design (for example, the cosmetic design 200 of Figure 2A). A core material 310 can form the center of a particle, around which a number of layers can be arranged. The example of the photochromic formulation 300 is illustrated as a number of concentric layers for the sake of simplicity, although it is understood that the layers may have a surface structure resulting from the morphology of the layers and / or the processes applied to synthesize the materials.Around the core material 310, the example photochromic formulation 300 may include a photochromic layer 330. In some embodiments, a shimmer control layer 320 may be interposed between the core material 310 and the photochromic layer 330. Similarly, an encapsulation layer 340 may be disposed over the photochromic layer 330. In some embodiments, the particle may be characterized by a characteristic dimension, such as a diameter 350.

[0042] The core material 310 may be or comprise a reflective mineral. In some embodiments, the reflective mineral may be or comprise mica, titanium dioxide, or silicon dioxide. In this way, the core material 310 can impart a shimmer, amplify the color effect of the photochromic formulation 300, and give the photochromic formulation 300 a specular color. In some embodiments, the core material 310 The core material 310 may be or include a material that fluoresces under ambient conditions (e.g., sunlight, UV, etc.), for example, titanium oxide nanoparticles. In this way, the core material 310 can provide a white base to enhance the color fidelity of the photochromic layer 330. Similarly, the core material 310 may be or include a polymer material characterized by a diffuse color, which can be selected from a range of shades or tones. In an illustrative example, the core material 310 comprises a mixture of titanium oxide nanoparticles suspended in a white polymer microbead with a diameter of 0.1 to 5 µm, or larger. In this example, the core material 310 can provide a diffuse white base for the photochromic layer 330 under indoor conditions, and a bright white base under sunlight conditions, which will amplify the perceived intensity of the photochromic layer.Advantageously, such an approach allows the photochromic formulation 300 to respond to changing ambient conditions by amplifying or attenuating the brightness of the color.

[0043] The shimmer control layer 320, interposed between the core material 310 and the photochromic layer 330, may be or comprise a photoreactive material characterized by a transition from visible transparency to visible opacity when exposed to irradiation of a characteristic wavelength. The visible opacity may correspond to a broad reflectance in the visible spectrum. Alternatively, the visible opacity may correspond to a solid diffuse color. In this way, the shimmer control layer 320 can modulate any optical property of the core material 310 independently of the photochromic layer 330. In some embodiments, the transition from visible transparency to visible opacity is gradual and proportional to the intensity of the irradiation.For example, the shimmering regulating layer may be or include a photoreactive polymer, such as but not limited to spiropyran, spirooxazines, diarylethenes, or naphtopyran, which undergoes a physical confirmation or electronic state transition in response to irradiation at the characteristic wavelength. As an illustrative example, spiropyran undergoes a transition under UV irradiation to absorb photons of visible light, thus appearing colored. When the UV source is removed, the molecules gradually release back to their ground state.Without being limited to a particular range, the characteristic wavelength may be in the UV range, such as approximately 400 nm or less, approximately 380 nm or less, approximately 360 nm or less, approximately 340 nm or less, approximately 320 nm or less, within the energy ranges that human skin is adapted to absorb at least intermittently (e.g., UV-A and / or UVB). In some embodiments, the characteristic wavelength may be in the visible range, approximately 380 nm. nm to 750 nm, so that the iridescence regulating layer can be modulated between a UV absorber and a visible light absorber under irradiation with visible light, which may be preferred to UV light for some users. For example, some diarylethene coordination complexes, such as polyoxometalate diarylethene coordination complexes, transition from UV absorbers to broad-spectrum absorbers from approximately 425 nm to approximately 800 nm, centered around a wavelength of approximately 620 nm after irradiation at a characteristic wavelength of 400 nm. In this context, the term "approximately" is used to indicate a margin of ±5% on either side of the stated value.

[0044] The photochromic layer 330 may be or comprise multiple photochromic materials. The photochromic materials may be or comprise materials selected to provide a color rendering dyad, triad, tetrad, or a greater number of materials, with which a range of colors represented in the cosmetic design (for example, the cosmetic design 200 of Figure 2) can be rendered with acceptable fidelity to satisfy the user's aesthetic sense. In some embodiments, the photochromic layer comprises three photochromic materials to render a cyan-magenta-yellow (CMY) triad.In some embodiments, each of the three photochromic materials is individually modulated by a respective characteristic wavelength, where a first characteristic wavelength, a second characteristic wavelength, and a third characteristic wavelength are different wavelengths. To reduce crosstalk between the color channels in the photochromic layer, the three characteristic wavelengths can be provided by an illumination source (e.g., the illumination source(s) 108 of [Fig. 1]) with three distinct wavelength channels, such as linear sources or filtered light sources (e.g., an RGB projector).

[0045] For example, a first tint or a first photoreactive pigment may be included, characterized by a reversible diffuse reflectance at a first central wavelength of 490 nm to 520 nm in response to irradiation by photons of a first characteristic wavelength. In this way, the first central wavelength may correspond to the cyan portion of the CMY triad. In some embodiments, the first characteristic wavelength may be an activation wavelength or a deactivation wavelength, so that the first tint or the first photoreactive pigment may exhibit a stable transparency that is modulated into a stable diffuse color in response to irradiation at the first characteristic wavelength. Alternatively, the first tint or the first photoreactive pigment may exhibit a stable diffuse color that is modulated in a stable transparency in response to irradiation at the first characteristic wavelength. For example, for deactivation mechanisms, the first characteristic wavelength can be from approximately 625 nm to approximately 740 nm, which corresponds to red light. For activation mechanisms, the first characteristic wavelength can generally be in the ultraviolet range, as described above. In this context, the term "approximately" is used to indicate a margin of ±5% on either side of the stated value.

[0046] Similarly, a second tint or photoreactive pigment can be characterized by a reversible diffuse reflectance at a second central wavelength of 570 nm to 590 nm in response to irradiation by photons of a second characteristic wavelength. In this way, the second central wavelength can correspond to the yellow portion of the CMY triad. As described with reference to the first tint or photoreactive pigment, the second tint or photoreactive pigment can be modulated by an activation or deactivation mechanism. For deactivation mechanisms, the second characteristic wavelength is approximately 450 nm to approximately 495 nm, which corresponds to blue light. For activation mechanisms, the second characteristic wavelength can generally be in the ultraviolet range, as described above.In this context, the term "approximately" is used to indicate a margin of ±5% on either side of the stated value.

[0047] Similarly, a third color or third photoreactive pigment can be characterized by a reversible diffuse reflectance at a third central wavelength of 450 nm to 495 nm and at a fourth central wavelength of 625 nm to 740 nm in response to irradiation by photons of a third characteristic wavelength. In this way, the third color or third photoreactive pigment can correspond to the magenta portion of the CMY triad. As described with reference to the first color or first photoreactive pigment, the third color or third photoreactive pigment can be modulated by an activation or deactivation mechanism. For deactivation mechanisms, the second characteristic wavelength can be from approximately 495 nm to approximately 570 nm, which corresponds to green light.For activation mechanisms, the second characteristic wavelength can generally be in the ultraviolet range, as described above. In this context, the term "approximately" is used to indicate a margin of ±5% on either side of the stated value. In some embodiments, the third tint or third photoreactive pigment may be or comprise more than one type of photoreactive molecule to confer the third central wavelength and the fourth central wavelength, rather than a single molecular structure conferring both.

[0048] In certain embodiments, the photochromic layer 330 may be or comprise, but not limited to, photochromic materials such as spiropyrans, spirooxazines, diarylethenes, azobenzenes, quinones, silver halides, or zinc halides. For example, the first photoreactive pigment may be or comprise 1,2-bis(2-methyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluorocyclopentene. The second photoreactive pigment may be or comprise 1,2-bis(2-methyl-5-phenyl-3-thienyl)-3,3,4,4,5,5-hexafluorocyclopentene. The third photoreactive pigment may be or comprise 1,2-bis(3-methylbenzo(b)thiophen-2-yl)perfluorocyclopentene. In some embodiments, the photochromic layer may be or comprise a mixture of materials described by their trade name. For example, with reference to the DAE naming system developed by Yamada Chemical Company, LTD.From Japan, the photochromic layer may be or include the photochromic tints DAE-0001, DAE-0012 and DAE-0068. Other DAE tints or pigments may be available, including but not limited to DAE-0002, DAE-0003, DAE-0004, DAE-0005, DAE-0015, DAE-0016, DAE-0017, DAE-0018, DAE-0019, DAE-0020, or other functional photochromic tints or pigments classified as 'p-type' that isomerize in response to irradiation.

[0049] In some embodiments, the photochromic layer 330 may also include a fourth photochromic material to provide a black channel that is part of a CMYK tetrad (also called a "key" channel). Like the photochromic materials described above, the fourth photochromic material can be characterized by a transition from visible transparency to visible opacity when exposed to irradiation of a characteristic wavelength (e.g., UV photons). Unlike the materials of the CMY triad, the K material can be isomerized between a broad absorber (e.g., a diffuse black color) in the visible spectrum and a broad emitter (e.g., transparent). The inclusion of the fourth photochromic material to provide the K channel in the photochromic layer 330 improves the color rendering fidelity of the photochromic formulation, as observed in CMYK printing systems.

[0050] In addition or alternatively, the photochromic layer 330 may be or comprise a material that exhibits structural color. Unlike pigments and tints, structural color is generated by interference effects caused by the structure of the material, rather than by the absorption of photons by electrons in atomic or molecular orbitals. In multilayer thin-film materials, for example, structural color may result from a wavelength-dependent phase shift that produces interference in a characteristic pattern in the visible spectrum, observed as a color. However, unlike the photochromic materials described above, the structural color can be fixed, rather than undergoing a transition between two color states.

[0051] In this way, the photochromic layer 330 can be a structural color layer, comprising one of three or more structural color materials. Unlike the photochromic pigments or tints described above, which render colors by subtractive color mixing, structural color is typically not sensitive to modulation by an on / off wavelength. Instead, materials exhibiting structural color are typically characterized by a static, wavelength-dependent color, which manifests itself in response to exposure to photons of a specific wavelength, polarity, or other characteristic property. In this way, structural color materials can be selected to reproduce an additive color triad. Examples of additive color triads include, but are not limited to, an "RGB" triad, as in addressable pixel displays.In this way, the 300 photochromic formulation can comprise a mixture of particles with different structural color materials, the proportions of which can be chosen to produce different color rendering capabilities. In an illustrated example, the photochromic formulation might comprise a mixture of red structural color particles, green structural color particles, and blue structural color particles in substantially equal proportions (e.g., 1:1:1 -R:G:B). In this context, "substantially" is used to indicate a distribution of values ​​within ±10% of the stated value.

[0052] In some embodiments, the structural color is imparted to the photochromic layer 330 by a nanostructured or microstructured material. For example, the structural color layer may be or comprise porous clusters suspended in a photoreactive matrix. The porous clusters may be or comprise inverse opals, which can be formed from silicon dioxide or titanium dioxide. Inverse opals are macroporous photonic crystal particles ordered in three dimensions, characterized by a structural color that can be tuned by synthesis parameters. For example, by the synthesis of silicon dioxide crystals in a colloidal matrix model that forms the photonic crystal structure after pyrolysis. As a photonic crystal material, a powder of the material can retain the structural color properties of the bulk crystal.In this way, a suspension of porous clusters that act as photonic crystals can be incorporated into a photochromic material that acts as the photoreactive matrix. Thus, the structural color layer can be provided by the material. of core 310, where the core material comprises a photonic crystal characterized by a structural color.

[0053] In turn, the photoreactive matrix modulates the exposure of the porous clusters to incident photons by transitioning from transparency to opacity under irradiation by a characteristic actuation / modulation wavelength. Like the photochromic materials described above, the photoreactive matrix can be characterized by a transition from visible transparency to visible opacity, or vice versa, when exposed to irradiation of a characteristic wavelength (e.g., UV photons, visible photons, or infrared photons). As with the K-channel material or the shimmer regulating layer 320, the photoreactive matrix material can be isomerized between a broad absorber (e.g., a diffuse black color), a broad reflector (e.g., a diffuse white color), or a narrow reflector (e.g., a specific diffuse color) into a broad emitter (e.g., transparent).Specific diffuse color can be used, for example, to provide a neutral tone that can be matched to skin tone, while black or white matrix materials can be used to provide bases to promote color rendering fidelity. In some embodiments, specific diffuse color can be provided by mixing several photochromic materials in the photoreactive matrix, so that the characteristic wavelength can include several wavelengths that modulate the mixture together.

[0054] Regarding the structures illustrated in [Fig. 3], the photochromic layer 330, as a structural color layer, may comprise a first photonic crystal material characterized by a first structural color in the blue range. The structural color layer may comprise a second photonic crystal material characterized by a second structural color in the green range. The structural color layer may comprise a third photonic crystal material characterized by a third structural color in the red range. Unlike the photochromic materials, the structural color layer may be limited to a single structural color rather than a mixture of the three.In this way, three color channels can be independently modulated by supplying three different photoreactive matrix materials to three photonic crystal materials, each chosen to isomerize in response to irradiation by a different respective wavelength. As described in more detail with reference to [Fig. 4B], a mixture of three different structural color materials, incorporating three different photoreactive matrix materials, can allow the application of a cosmetic design using a network of color tuples, applied by modulation. photoreactive matrix materials, to provide differential color by subtractive mixing.

[0055] Above the photochromic layer 330, the photochromic formulation 300 may include an encapsulation layer 340. The encapsulation layer 340 may be or include an inert polymer material providing a chemical and / or diffusion barrier to protect the underlying materials from chemical oxidation or other degradation reactions. Similarly, the encapsulation layer may isolate the materials constituting the photochromic layer 330, the shimmer-regulating layer 320, and the core material 310 from body surfaces (e.g., the face of subject 102 in [Fig. 1]). The encapsulation layer 340 may be or include a material that is transparent to photons in the UV and visible wavelengths. For example, the encapsulation layer may be or include a silicone material, such as polydimethylsiloxane (PDMS).

[0056] Figure 4A is a schematic illustration of photomodulation of an example of a photochromic formulation 400, in accordance with various embodiments. The photochromic formulation 400 may be an example of the photochromic formulation 300 of Figure 3, incorporating a photoreactive pigment or tint and / or a structural color material. From an external perspective, a photochromic formulation 400 may be stable in a first state 410. The first state 410 may describe a first diffuse color, such as white, black, or a color chosen from a palette of skin tones (for example, a sum color produced by additive mixing of several photochromic materials). Alternatively, the first state 410 may be at least partially transparent, in order to reduce the visual profile of the first state 410 and to blend the photochromic formulation 400 into the body surface on the back.

[0057] Under irradiation by photons of one or more characteristic wavelengths 415, the photochromic formulation can transition from the first state 410 to a second state 420. The second state 420 can be characterized by a diffuse color, as when the photochromic formulation 400 comprises a photonic crystal or a mixture of photochromic materials. As described above, the diffuse color can result from a mixture of structural colors or subtractive mixing, and can be characterized by a wavelength-dependent reflectance of photons of one or more wavelengths 425. For photochromic materials, the color rendering results from the subtractive mixing of two or more photoreactive pigments, whereas for structural colors, each particle can be characterized by a single diffuse color. Thus, the number of wavelengths 425 corresponds to the type of material composing the photochromic formulation 400.In an illustrative example, for a structural color particle, the characteristic wavelength. 415 can be found in the visible spectrum and can be used to effect a transition of a photoreactive material, such as spiropyran or naphthopyran, from a diffuse black color to a transparent color, thus revealing a photonic crystal layer (e.g., layer 330 or core material 310 in [Fig. 3]), which reflects the 425 wavelength. Similarly, for a photochromic tint or pigment particle, the characteristic 415 wavelength can include multiple wavelengths to modulate a triad or tetrad of photoreactive materials, resulting in subtractive color mixing. As described above, in such cases, the 425 wavelength can include multiple wavelengths, received and interpreted by the human eye as a single diffuse color.

[0058] In some embodiments, the photochromic formulation 400 can be "locked" in the second state 420. In this context, "locking" refers to a process by which the photochromic formulation 400 comprises a photoreactive material that isomerizes, polymerizes, or undergoes another chemical change in response to irradiation by a "locking" wavelength, different from the characteristic wavelength 415. The photoreactive material can be an example of the encapsulation layer (for example, the encapsulation layer 340 of [Fig. 3]), and the change can result in the absorption by the encapsulation layer of the characteristic wavelength 415 and the prevention of any further modulation of the photochromic material.In an illustrated example, when the second state 420 is stable after irradiation under the characteristic wavelength 415 in the UV range, the encapsulation layer of the photochromic formulation 400 can be photopolymerized to become a UV-absorbing polymer, after which the photochromic formulation 400 is "locked" in the second state 420. Locking, as such, can also be applied to matrix materials.

[0059] Figure 4B describes spectroscopic aspects of the photochromic system, comprising an intensity spectrum of 450 and an absorbance spectrum of 460 for three illumination sources and three photochromic materials, respectively, in accordance with various embodiments. The photochromic formulation with which the cosmetic design (for example, the cosmetic design example 200 in Figure 2) is implemented may be or comprise a mixture of several photoreactive and / or photochromic materials, as described with reference to Figure 3 and Figure 4B. In the illustrated spectral examples, the intensity spectrum of 450 represents excitation or deactivation spectra of three different photochromic or photoreactive materials. For example, the three materials may correspond to a CMY triad where each color channel is modulated independently by a wavelength wavelength included in the intensity spectrum 450. Alternatively, the three materials can correspond to three different photoreactive materials which each undergo a transition from transparency to opacity under the effect of irradiation by a respective wavelength of the intensity spectrum 450.

[0060] Each constituent peak of the spectrum 450 can be generated by the illumination source of the system 100 described with reference to [Fig. 1]. For example, a first emission peak 451, corresponding to a bluish color in the visual spectrum, can be chosen to correspond to a first absorbance band 461 of one of the materials. Similarly, a second emission peak 453 can be chosen to correspond to a second absorbance band 463 of a second material. Likewise, a third emission peak 455 can be selected to correspond to a third absorption band 465 of a third material. In this way, the illumination source (for example, the illumination source(s) 108 of [Fig. 1]) can be configured to expose the photochromic formulation at or near the maximum absorbance values ​​of the materials, as illustrated in the absorbance spectra 460.For example, the three linear sources 451, 453, and 455 of the emission spectrum 450 are aligned with three central wavelengths Xi_3 to independently modulate three color channels (CMY, RGB, or other) as an approach to rendering a full color spectrum as described in the cosmetic drawing in Figure 2 (e.g., cosmetic drawing 200 in Figure 2). In some embodiments, the three central wavelengths may be in the ranges of 410–475 nm, 490–540 nm, and 600–670 nm, respectively, corresponding to bluish, greenish, and reddish lights. In this context, the term "central wavelength" describes a peak in emission intensity around which the intensity follows an emission intensity distribution, as determined by the optical properties of the illumination source, which may differ for different emission modalities.For example, a linear coherent source (e.g., a laser) can emit at a characteristic central wavelength with a relatively narrow distribution on either side. In contrast, a broad-spectrum illumination source, such as a blackbody source, can be characterized by a wavelength distribution determined by the bandwidth of a filter used to select a given central wavelength. In this way, an illumination source can emit photons at a central wavelength within one of the ranges described above, characterized by a higher- and lower-energy emission intensity distribution determined by the source and optics. In some embodiments, the central wavelengths can be in the ultraviolet spectral range below 400 nm or in the NIR or IR ranges above 750 nm.

[0061] In some embodiments, the central wavelengths of the illumination source(s) are different. Even in this case, channel crosstalk may be observed in some instances when the emission intensity distributions for one or more wavelengths are sufficiently broad to overlap with the nearest neighboring central wavelength. Although crosstalk can impair the individual addressability of the respective photoreactive materials, limited crosstalk may have a limited or negligible impact on color rendering fidelity when the photochromatic dynamic range is relatively slow or when the colors are typically blended. For example, a first photoreactive pigment or tint may respond to bluish light relatively quickly, while a second photoreactive pigment or tint may respond to greenish light relatively slowly.Thus, when the emission intensity of a bluish central wavelength can extend into the greenish range, the exposure time of the green-sensitive material to greenish illumination can be such that little or no transition is observed in the green-sensitive material. Similarly, relatively few colors completely exclude one or more channels from the triad or tetrad. In this way, the relative impact of low-level channel overlap can be limited to a marginal change, rather than an abrupt change in color rendering intensity.

[0062] Figure 5 is a schematic illustration of a photochromic formulation 500 under front illumination 501 and under small-angle illumination 503 using the system of Figure 1 for producing polychromatic designs, in accordance with various embodiments. As illustrated, the photochromic formulation 500 comprises a plurality of particulate photochromic materials 510 in various color states as modulated by the illumination source (for example, the illumination source 108 of Figure 1). As shown, a first subset of photochromic materials 510, exposed to front illumination 501, express a first color state 511, while a second subset of photochromic materials 510, exposed to small-angle illumination 503, express a second color state 513.

[0063] As illustrated, the photochromic formulation 500 may be or comprise a photoreactive powder comprising a mixture of photochromic materials, as described with reference to [Fig. 3]. In addition, or alternatively, the photochromic formulation 500 may comprise a matrix material 515, such as a neutral cream or ointment that is transparent to the excitation wavelengths used to modulate the photochromic materials 510. The matrix material 515 may serve to make the photochromic materials 510 adhere to the skin surface 517 (for example, in the region of interest 120 of [Fig. 1]), so that the design is preserved or It does not run, for example, in response to perspiration or other physiological processes. In some embodiments, the matrix material 515 may include a dispersive material, such as a metallic ceramic (e.g., titanium dioxide), to absorb ultraviolet energy, so that the skin surface 517 can benefit from additional protection. As described in more detail with reference to [Fig. 6], front illumination 401 and small-angle illumination 503 can be provided by the same illumination source by reorienting the skin surface 517 relative to the illumination source. In some embodiments, the system controlling the illumination source can incorporate multiple illumination sources in multiple orientations, so that front illumination 501 and small-angle illumination 503 can be provided in a single position.

[0064] Figure 6 is a flowchart illustrating an example of a method for applying a cosmetic design using the photochromic material of Figure 3, in accordance with various embodiments. The example method 600 is carried out by a computer system comprising one or more computing devices, such as the client computing device 104 of Figure 1 or the client computing device 501 of Figure 1. The example method 600 can be stored as computer-executable instructions on a computer-readable memory device. In this way, the computer system can implement the operations of the example method 600 as part of the execution of the instructions.

[0065] In operation 602, the computer system receives a digital representation of a cosmetic design. The digital representation of the cosmetic design includes a color intensity information tensor for a plurality of colors. The plurality of colors corresponds to a cosmetic composition (for example, the photochromatic formulation 500 of [Fig. 5]) comprising a mixture of photochromic materials. The computer system can receive the digital representation of the cosmetic design (for example, the cosmetic design 200 of Figure 2) from a user via a user interface of the computer system or via a personal electronic device.The digital representation of the cosmetic design can be associated with a unique design identifier and can be retrieved from a data store, so that the color intensity information tensor can be requested and / or retrieved by the computer system in response to receiving the unique design identifier.

[0066] In operation 604, the computer system detects, using a camera in electronic communication with the computer system, a system user facing a mirror for visible light (for example, mirror 106 of [Fig. 1]). In some embodiments, the camera is in optical communication with the mirror for visible light via a partially transparent portion of the mirror for visible light (e.g., the first portion 112-1 of [Fig. 1]). In this context, user detection may involve multiple operations included within face detection and recognition routines. For example, the computer system may store feature data for a number of faces, so that the computer system is able to detect and identify the face present in the camera's field of view (e.g., field of view 152 of [Fig. 1]). Such identification can be advantageous for the system by reducing the resource demand associated with generating face maps and projections. For example, by storing depth and image data (e.g., in the user profile data store 585 of [Fig. 1]).5]), the computer system can rely on periodic resetting for 3D mapping operations, rather than continuous mapping, which can be more computationally intensive.

[0067] The process 600 may optionally include the generation, by the computer system, of a prompt for the user to apply the mixture of photochromic materials to operation 606. As described with reference to [Fig. 1], prompting the user to apply the photochromic formulation (for example, the photochromic formulation 500 of [Fig. 5]) may be one of several visual / auditory guides or prompts provided to the user. These prompts may facilitate the application of cosmetic designs, for example, when the client computer device is not equipped with a sensor to detect the presence of the photochromic formulation. In some embodiments, the photochromic formulation includes a constituent compound or a material that is optically detectable. For example, a matrix (for example, the matrix material 515 of [Fig. 1]).5]) may include a material that absorbs a characteristic wavelength for which the computer system has a source that is typically reflected by human skin. In addition and / or alternatively, the matrix may include a material that reflects or fluoresces under a characteristic wavelength of illumination. In this way, the optional operation 606 can be triggered in response to the computer system's determination that the user has not applied the photochromatic formulation.

[0068] In operation 608, the computer system generates, using the camera, a digital representation of a portion of the user's face (for example, the region of interest 120 of face 102 of the subject in [Fig. 1]). The digital representation of the face includes a position information tensor defining a surface of the face. The position information tensor is described in other terms as a face map or a 3D map of the user's face. The system A computer can implement various techniques to collect and generate depth data describing the surface onto which the cosmetic design will be applied. For example, the computer system may include, or be electronically coupled to, sensors including, but not limited to, time-of-flight cameras, stereoscopic cameras, LiDAR sensors, or point-tracking systems, to generate the digital representation of the face. As described in more detail with reference to [Fig. 1], the digital representation of the face can be stored in the computer system's memory and / or in a separate data store for use in generating projections of the cosmetic design onto the face map.

[0069] In operation 610, the computer system defines one or more exposure patterns for the face surface, at least in part by projecting the color intensity information tensor onto the position information tensor. As described in more detail with reference to Figures 2 to 4, the exposure patterns may include data for a set of characteristic wavelengths generated by sources incorporated into the computer system or in electronic communication with it. For example, an exposure pattern may include levels and durations of localized emission in space for each polygon in a polygon map (for example, the 212 polygons in [Fig. 2B]) corresponding to a position on the face. In this way, the computer system can generate an exposure sequence, in terms of training instructions for the sources, to apply the cosmetic design to the user's specific face.

[0070] In operation 612, using an illumination source (for example, the illumination source 108 of [Fig. 1]) in electronic communication with the computer system, the computer system exposes a portion of the user's skin (for example, the region of interest 120 of [Fig. 1]) to a plurality of distinct wavelength channels. The exposure is carried out in accordance with the exposure pattern. In some embodiments, the illumination source is physically coupled to the mirror for visible light and configured to emit the plurality of distinct wavelength channels. In some embodiments, the illumination source is optically coupled to the mirror via a unidirectional transparent portion (for example, the second portion 112-2 of [Fig. 1]).l]), so that the illumination source emits the plurality of distinct wavelength channels through the mirror via the unidirectional transparent portion. The sources can be oriented by the computer system as part of processing the exposure pattern into drive instructions for the sources. For example, the sources may include beam-guiding optics that rely on electronic actuation or dynamic lenses / optics to direct the . beam from the source to a specific position on the face. In some embodiments, the sources are configured to emit a light field covering the entire surface, but with a variable wavelength content at each of a number of pixels, reproducing the projected design, as described in more detail with reference to [Fig. 2B]. In this case, the sources may include dynamic filters, such as programmable diffraction gratings or programmable filter arrays. Operation 612 may optionally include locking the design by an additional exposure with a locking wavelength, as described with reference to [Fig. 4A].

[0071] The method 600 may optionally include step 614, whereby the computer system generates a second prompt for the user to reposition themselves relative to the cameras (for example, from a frontal to a semi-profile posture), so that the illumination sources can be aligned with a different portion of the face. As described in more detail with reference to [Fig. 5], multiple exposure angles can impart an angular color effect, such as iridescence, to the photochromatic formulation, which is not typically available with pigment-based cosmetics. Following step 614, the method 600 may optionally include step 616, whereby the computer system exposes the user's face according to a second exposure pattern.The second exposure pattern may include small-angle illumination, as part of the application of angular or layered color to the first portion of the user's face exposed in operation 612. Similarly, operation 616 may include frontal illumination of a second portion of the user's face, so that a different region may express a color pattern according to the cosmetic design received in operation 602.

[0072] Figure 7 is a functional diagram that illustrates aspects of an example computing device 700, according to various embodiments. Although many different types of computing devices have been discussed above, the example computing device 700 describes various features that are common to many different types of computing devices. While Figure 7 is described with reference to a computing device that is implemented as a device on a network, the description below is applicable to servers, personal computers, mobile phones, smartphones, tablets, embedded computing devices, and other devices that can be used to implement portions of embodiments of this disclosure.Furthermore, the person in the trade and others will recognize that the 700 computer device can be any one of any number of devices currently available or yet to be developed.

[0073] In its most basic configuration, the computing device 700 comprises at least one processor 702 and a system memory 704 connected by a communication bus 706. Depending on the exact configuration and type of device, the system memory 704 may be volatile or non-volatile memory, such as read-only memory (“ROM”), random-access memory (“RAM”), EEPROM, flash memory, or similar memory technology. Those skilled in the art and others will recognize that the system memory 704 typically stores data and / or program modules that are immediately accessible to the processor 702 and / or on which it is currently operating. In this respect, the processor 702 can serve as the computing center of the computing device 700 by handling the execution of instructions.

[0074] As further illustrated in [Fig. 7], the computer device 700 may include a network interface 710 comprising one or more components for communicating with other devices on a network. Embodiments of this disclosure may access basic services that use the network interface 710 to perform communications using common network protocols. The network interface 710 may also include a wireless network interface configured to communicate via one or more wireless communication protocols, such as Wi-Fi, 2G, 3G, LTE, WiMAX, Bluetooth, Bluetooth Low Energy, and / or similar protocols. As a person skilled in the art will understand, the network interface 710 illustrated in [Fig. 7] may represent one or more of the wireless or physical communication interfaces described and illustrated above with respect to particular components of the system 100.

[0075] In the example embodiment shown in [Fig. 7], the computer device 700 also includes a storage medium 708. However, the services can be accessed using a computer device that does not include means for storing data on a local storage medium. Therefore, the storage medium 708 shown in [Fig. 7] is represented by a dashed line to indicate that the storage medium 708 is optional. In all cases, the storage medium 708 may be volatile or non-volatile, removable or non-removable, implemented using any technology capable of storing information, including, but not limited to, a hard disk drive, a solid-state drive, a CD-ROM, a DVD or other disk storage, magnetic cassettes, magnetic tape, magnetic disk storage, and / or the like.

[0076] As used herein, the term "computer-readable medium" includes volatile and non-volatile and removable and non-removable media implemented in any process or technology capable of storing information, such as instructions Computer-readable data structures, program modules, or other data. In this regard, system memory 704 and storage medium 708 shown in [Fig. 7] are only examples of computer-readable media.

[0077] Suitable implementations of computing devices comprising a processor 702, system memory 704, a communication bus 706, a storage medium 708, and a network interface 710 are known and commercially available. For ease of illustration and because it is not important for understanding the claimed subject matter, [Fig. 7] does not show some of the typical components of many computing devices. In this regard, the computing device 700 may include input devices, such as a keyboard, numeric keypad, mouse, microphone, touch input device, touchscreen, and / or the like. These input devices may be coupled to the computing device 700 by wired or wireless connections including RF, infrared, serial, parallel, Bluetooth, Bluetooth Low Energy, USB, or other suitable connection protocols using wireless or physical connections.Similarly, the 700 computer device may also include output devices such as a display, speakers, a printer, etc. These devices being well known in the art, they are not illustrated or described further in this document.

[0078] While illustrative embodiments have been illustrated and described, it will be appreciated that various modifications can be made to them without departing from the spirit and scope of the devices, processes and systems described.

Claims

Demands

1. Photochromic formulation, comprising: a core material; and a photochromic layer covering the core material and forming a particle centered around the core material, the photochromic layer comprising a plurality of photochromic materials, including: a first photoreactive pigment characterized by a reversible diffuse reflectance at a first central wavelength of 490 nm to 520 nm in response to irradiation by photons of a first characteristic wavelength; a second photoreactive pigment characterized by a reversible diffuse reflectance at a second central wavelength of 570 nm to 590 nm in response to irradiation by photons of a second characteristic wavelength;and a third photoreactive pigment characterized by a reversible diffuse reflectance at a third central wavelength of 450 nm to 495 nm and a fourth central wavelength of 625 nm to 740 nm in response to irradiation by photons of a third characteristic wavelength; wherein the first characteristic wavelength, the second characteristic wavelength, and the third characteristic wavelength are different.

2. Photochromic formulation according to claim 1, wherein the photochromic layer comprises spiropyrans, spirooxazines, diarylethenes, azobenzenes, quinones, silver halides or zinc halides.

3. Photochromic formulation according to claim 1, wherein the core material comprises a reflective mineral.

4. Photochromic formulation according to claim 3, wherein the reflective mineral comprises mica, titanium oxide or silicon oxide.

5. Photochromic formulation according to claim 1, wherein the particle is characterized by a diameter less than or equal to 20 micrometers.

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