Multifunctional face mask

Abstract

A flexible light-emitting face 100 mask comprising, a light emitter circuit comprising, a plurality of light emitters 10 arranged on an inner face 2 of the mask an configured in use to emit light towa

Description

FIELD OF THE INVENTION The present disclosure relates to flexible light-emitting face masks designed for therapeutic, cosmetic, and / or medical applications. BACKGROUND TO THE INVENTION Light-emitting face masks are used to deliver therapeutic light to the skin. Such masks typically use LEDs emitting red, blue, or near-infrared light to promote skin rejuvenation, reduce acne, and provide other cosmetic or therapeutic benefits. Existing masks are generally made from non-rigid materials and are designed to sit in place on a user's face. However, current designs have limited versatility, comfort and efficiency. Accordingly, there is a need to provide improved light-emitting face marks. SUMMARY OF THE INVENTION According to a first aspect, there is provided a flexible light-emitting face mask comprising: a light emitter circuit comprising a plurality of light emitters arranged on an inner face of the mask and configured in use to emit light towards a skin surface of a user when wearing the mask; a pair of openings located laterally either side of a mask nose region; and, a pair of slits dividing the mask into an upper mask region and lower mask region joined through the mask nose region, each slit extending laterally from one of the openings to a peripheral edge of the mask, wherein the upper mask region and lower mask region are foldable relative to each other around a folding axis extending laterally through the nose region. Unless stated otherwise, relative directions referred to herein in relation to exemplary face masks are defined in relation to the mask's orientation in use when worn as a face mask. For example, "mask inner face" or "mask back face" would mean the face which would face towards the user (in use), while the "mask outer face" or mask "front face" would be the opposing face on the outwards-facing exterior of the mask. Similarly, "mask top edge" refers to the edge which would be closest to the top of the user's head (in use), a "front view" is a view looking towards the front face of the mask. It will be understood that regions of their mask may be defined based on their proximity to particular regions of the user's body in use in a particular configuration. For example, the mask nose region is proximal to the user's nose when the mask configured and worn as a face mask, while the upper and lower mask regions sit proximal to the upper and lower parts of the face, respectively. The slits improve the flexibility of the face mask, allowing it to contour or fold around the folding axis. This may enable the mask to be reconfigured for use on other body parts such as the neck, cranium, elbows, and knees, or adjusted for different user face sizes. The arrangement of the slits extending from the eye holes particularly improves the flexibility of the mask. The slits and openings, which may also be referred to as "eye holes", together create a narrow nose region with a low second moment of area and hence low bending stiffness, acting as a bridge between the upper and lower mask regions. This enables the mask nose region to flex more easily, and thereby allows the mask to be reconfigured into different geometries and put to different uses. For example, as will be discussed in further detail below, the upper mask region may be folded relative to the lower mask region such that the mask can be bent around a user's knee or elbow. Examples of such configurations will be discussed in further detail below. Hence, while the mask may be referred to as a "face mask", it is in fact a multipurpose mask suitable for wearing on many parts of the body. The upper and lower mask regions may both be flexible, in the sense that they comprise flexible materials which can be contoured between different geometries along one or more axes. For example, the mask may be configured for wearing around a user's neck, by bending the upper mask region of the mask while the lower mask region remains flat. The upper and lower mask regions each comprise a main body made of silicone or other flexible material. In some examples, the upper and / or lower mask regions may be partially or substantially rigid. In such examples, the mask is configured such that its geometry may still be changed, for example by at least the nose region being flexible. Alternatively, or additionally, the nose region may be substantially rigid and may comprise one or more components configured to allow the mask to be folded, such as one or more hinges. By allowing the nose region to be foldable (with a component such as a hinge and / or by comprising a flexible material) the geometry of the mask may be altered without needing the entire mask to be flexible. The light emitters may comprise LEDs. In some examples, the light emitters may comprise a plurality of LEDs configured to emit light at a first wavelength and a plurality of LEDs configured to emit light at a second wavelength different to the first wavelength. The light emitters may be configured to emit light at wavelengths such as red, blue, near-infra red, or other therapeutic wavelengths. In an embodiment, the light emitter circuit comprises: an upper light emitter circuit in the upper mask region having a first array of light emitters; a lower light emitter circuit in the lower mask region having a second array of light emitters; and, a flexible electrical connector extending through the mask nose region and connecting together the upper circuit and the lower circuit, and optionally the electrical connector extends through a cheek bridge connecting the mask nose region to a cheek region of the lower mask region. This arrangement of the light emitter circuit may allow improved bending through the nose region. The light emitter circuit may comprise a distinct component, such as a PCB. In some examples, each light emitter circuit comprises a separate component, such as a PCB (which may be flexible), which are joined together by the electrical connector. In other examples, the mask may comprise a single component comprising both the upper and lower light emitter circuits. For example, a single flexible PCB may extend through both the upper and lower mask regions, with the flexible electrical connector being integrally formed into the PCB as a flexible bridge. The mask cheek bridge connects the cheek region (i.e. region below the eye holes) of the lower mask region to the mask nose region and is positioned below the eye hole. This mask cheek bridge maximises the gap between the eye holes and any cutouts required around the mask nose region to provide additional space for routing the electrical connections of the emitter circuits. It will be understood in general that the mask may be symmetric, such that it comprises two cheek regions. Other features may also be made symmetric across the mask. In an embodiment, the face mask comprises at least one controller for controlling the light emitters. The controller allows control of the activation of the mask and light emitters by the user or another person or device. In some example, the mask may comprise two or more controllers, with at least one controller configured to control the light emitters in the upper mask region, and at least one controller configured to control the light emitters in the lower mask region. In some examples, the light emitters may be divided into multiple distinct regions, each distinct region having a separate controller configured to control the light emission in that region. In an embodiment, the controller is adapted to receive an emission program for at least some of the light emitters. An emission program governs how the light emitters are activated across the mask. By selecting or modifying an emission program, the mask can be adapted for different use cases, increasing its versatility. The emission program may determine various behaviours, such as • an emission wavelength. For example, a particular emission program may activate only emitters of a particular colour. • an emission sequence. For example, a particular emission program may activate a set of emitters for a period of time, then deactivate the set of emitters and activate another set of emitters. The emitters may also be activated (or not activated) in specific regions of the mask, for example around the eyes or eye brows. • an emission pulse width. In some examples, it may be beneficial to pulse emitters at a particular frequency. The activation time and / or deactivation time may be modulated to create a particular pulse width. Together, the emission and sequence and emission pulse width may cause an emitter to e.g. pulse on and off at 10 second intervals for a 15 minute period. • an emission mask pattern, i.e. the pattern of activated and deactivated emitters across the inner face of the mask. For example, an emission pattern may only activate the emitters in the upper mask region and not the lower mask region. In some examples, all of the emitters of the mask may be controllable by the emission program. In other examples, the emission program may control only some of the emitters, with the remaining emitters simply remaining activated or deactivated, or controlled by a different emission program. In some examples, the controller may comprise a user input device used to select or modify emission programs, or otherwise for controlling an emission program of at least some of the plurality of light emitters. In an embodiment, each slit has opposing sides which define an elongate opening, as defined when mask is in a substantially flat configuration. This provides good coverage over the cheek of the user when the mask worn on the face. In an embodiment, the slits define an elongate opening having a width of between 0.1 mm and 20 mm, and optionally between 0.5 mm and 10 mm. In an embodiment, the face mask further comprises a nose reinforcement member for reinforcing the mask nose region. The reinforcement member inhibits excessive bending, and prevents the thin nose region from tearing. In an embodiment, the nose reinforcement member comprises a reinforcing rib. The reinforcement member may be formed from silicone, plastic, metal, composite, or gel. The reinforcement member may be disposed in any suitable location, including: on the PCB, built into the inner face of the mask, built into the outer face of the mask, a separate material between any of the layers, and / or on an outer surface of the mask. In an embodiment, the face mask further comprises a circuit support substrate for supporting the light emitter circuit, wherein the circuit support substrate comprises the reinforcement member, and optionally the reinforcement member is integrally formed with the circuit support. If the light emitter circuit comprises a PCB, then the circuit support substrate may be the circuit board itself. The reinforcement member may be attached and / or integrally formed into the circuit board, simplifying assembly while protecting the circuit board from damage. In an embodiment the face mask comprises a reinforcement member on the main body of the controller and a reinforcing rib, providing the maximum possible strength and flexibility. ... In an embodiment, the face mask further comprises a retaining system for configuring a geometry of the face mask selected from a set of predetermined geometries. That is, the retaining system allows the mask to be configured and held in a particular geometry and then reconfigured and held in a different geometry. This allows the mask to be reconfigured for different uses and users, as will be described herein. The retaining system may control the geometry of the mask while still allowing some relative movement and / or folding by the upper and lower mask regions. In an embodiment, the face mask further comprises an attachment system for releasably attaching the mask to the user. The attachment system may be distinct from the retaining system, and may comprise a strap or strap mounting system for attaching the mask to the body. In some examples, the attachment system may comprise a plurality of interchangeable straps or other mounts. For example, a first strap may be provided for attaching the mask to the head for use as a face mask, and a knee brace may be provided for attaching the mask around the knee for use as a knee mask. In an embodiment the set of predetermined geometries comprises: a first geometry in which the upper mask region and lower mask region are folded relative to each other to achieve a first predetermined angular separation therebetween at the mask nose region to provide a mask that can be worn on a user's face; and, a second geometry in which the upper mask region and lower mask region are folded relative to each other to achieve a second predetermined angular separation therebetween at the mask nose region to provide a mask that can be worn on one or more different parts of the body of the user, which may be selected from the cranium, torso, back, neck, shoulder, knee, and elbow. That is, the retaining system allows the mask to be worn as a face mask, while also allowing for the mask to be reconfigured to be worn on a different body part, such as the knee or scalp (i.e., the top of the cranium). The retaining system facilitates multi-functional use of the mask, and may allow the mask to be worn more easily on a wider range of body areas. In an embodiment, the first geometry or second geometry can be variably adjusted to fit different user body sizes. As well as facilitating "large" reconfigurations in which the mask geometry changes significantly (e.g. from a face-mountable configuration to a back-mountable configuration), the retaining system or another system may also support "small" reconfiguration, in order fit different user body sizes. For example, within the first geometry as a face-mountable mask, the mask may be adjusted for a larger or smaller face size. To provide easy reconfiguration, the retaining system may comprise snap buttons, with an engagement member being a stud and a retaining point being corresponding socket arranged to retain the stud. Alternatively or additionally, the retaining system may provide a continuous range or area of retaining points, to allow more precise adjustments. For example, the retaining system may comprise a slider or configuration adjustment strap which can be fixed at a particular retaining point. Other retaining systems will be familiar to the reader, such as Velcro, magnets and / or magnetic fasteners. In an embodiment, the retaining system comprises an engagement member located on one of the lower mask region and the upper mask region and a first retaining point located on the other mask region, the engagement member being releasably engageable at the first retaining point. This arrangement allows the relative geometries of the upper and lower mask region to be controlled, so as to constrain the mask into a particular geometry. In an embodiment the retaining system comprises a second retaining point, the first retaining point being located proximally to the slit and the second retaining point being located distally to the slit. By engaging the engagement member at the first retaining point, the mask is held in a less curved configuration, e.g. suitable for wearing the mask on the face. By engaging the engagement member at the second retaining point, the mask is held in a more curved configuration, allowing e.g. suitable for wearing the mask around the knee. In an embodiment, the face mask further comprises at least one spacer pad on the inner face of the mask. The spacer pads may have several functions, some of which are described below. In some examples, they may be configured to provide an airflow passage between the inner face of the mask and the skin of the user. Light emitters such as high-power LEDs may generate heat. Sufficient cooling of the face is advantageous as the energy from the emitters can raise the skin temperature. The spacer pads may provide an air gap between the user's skin and the mask to allow for convective cooling. Alternatively or additionally, the at least one spacer pad may be configured to block light from reaching one or more regions of the user's body. For example, the at least one spacer pad may be made of a non-transparent material and configured to block light from entering the user's eyes, where it could otherwise dazzle or injure a user. In some examples, the at least one spacer pads are configured to substantially block the light emitted by one or more of the light emitters, thereby protecting the user and allowing the user to more easily see through the mask. In such examples, the at least one spacer pads may advantageously allow for the user to more easily perform additional tasks while waring the mask, for example reading or using a mobile device. The spacer pads may also form part of the retaining system and assist in configuring a geometry of the face mask selected from a set of predetermined geometries. In an embodiment, the spacer pads are removably attachable to the mask. This may facilitate reconfiguration of the mask, because the spacer pads may be more useful in one geometry but less useful in another. For example, when the mask is being worn on the knee rather than the face, there is less need for spacer pads configured to block light from the eye regions of the mask. In an embodiment, the at least one spacer pad comprises a pair of eye pads around at least a portion of the periphery of each of the openings. The spacer pads may be configured to bear against the brow, temple, nose bone and / or cheek bone of the user in use, or other bony part of the user's face, allowing retaining forces to be comfortably transmitted between the user and the mask. In an embodiment the face mask further comprises a lattice, the support comprising a plurality of walls defining a plurality of cells, wherein at least some of the cells each encompass a respective light emitter of the plurality of light emitters. The walls of the lattice extend in the longitudinal direction i.e. between the inner and outer faces of the mask. The lattice may provide additional stiffness to control the geometry of the mask. Alternatively or additionally, the lattice may serve as a light guide, with the walls blocking light from light emitters from reflecting around the interior of the mask and directing it out towards the skin of the user. In an embodiment, the face mask further comprises: a transparent layer covering the light emitters; and, a plurality of lenses, each lens being integrally formed into the transparent layer and aligned with a respective light emitter of at least some of the plurality of light emitters. Light emitters such as LEDs are fragile and can become hot in use. Hence, there is a need to protect users from coming into contact with the light emitters. The current solution for light emitting masks is to either use individual lenses to cover the LEDs or an LED with a rounded lens built into the LED. These solutions add a large cost onto the production of an LED mask. By contrast, the transparent layer can be manufactured and fitted as a single unit, reducing cost and simplifying manufacturing. To further simplify assembly, the transparent layer may cover the entire inner side and plurality of light emitters. The transparent layer may comprise transparent silicone. In an embodiment, each lens comprises a dispersing lens. A dispersing lens disperses the light from the light emitters, spreading it out over the skin of the user. This may be particularly advantageous when the light emitters are point sources, such as small LEDs. In other embodiments, the lenses may alternatively comprise focusing lenses, which focus and direct the light into a particular area of the wearer's skin. In an embodiment, the transparent layer comprises: an emitter-facing side facing the plurality of light emitters; and, an opposing face opposite the emitter-facing side, and wherein each lens comprises a meniscus lens defined by a concave segment on the emitter-facing side and a convex segment on the opposing side, the convex segment having a larger radius than the concave segment. This arrangement creates a dispersing lens for spreading out light. In an embodiment, the face mask further comprises a reflective layer positioned behind the light emitters away from the inner face of the mask, the reflective layer being configured to reflect emitted light towards the skin of the user in use. Existing light emitting mask designs lose a lot of light due to reflection off of the skin back towards the mask and the energy being absorbed as heat. In an embodiment, the reflective layer comprises a specular reflector. Specular reflectors provide more efficient reflection compared to diffuse reflectors, because the light is reflected off the reflector in one direction back towards the user's skin, rather than re-emitted in diffusely in different directions (including directions away from the user's skin). The reflective layer may comprise holes, each hole aligning with a corresponding light emitter. This may facilitate fitting the reflective layer around the light emitters. In an embodiment, the reflector comprises a metallic reflector coating a non-electrically conductive core. A metallic reflector provides efficient specular reflection, but is electrically conductive. This may create a risk of short-circuiting the light emitter circuit. By coating (or otherwise enveloping) the metallic reflector on a non-conductive (that is, negligible conductivity compared to a metal, such as plastic) core, the electrical conductivity of the reflector is reduced and with it the risk of short-circuiting. According to a second aspect, there comprises a kit of parts, comprising: the face mask of any preceding claim; and a power source for the face mask. The power source may be internal within the face mask, or external to the face mask, such as an external battery pack or main supply. The power source may be connected to the face mask in a single location, or may connect to multiple locations. In either case, power from the power source may be transmitted between different portions of the mask via any suitable means, such as via one or more electrical connectors. In some examples, power may be transmitted from the power source to the face mask wirelessly. In an embodiment, the kit further comprises a user input device for controlling an emission program of at least some of the plurality of light emitters. The kit may further comprise a set of spacer pads. The kit may further comprise a set of interchangeable attachment systems. According to a third aspect, there comprises a flexible light-emitting mask, comprising: a light emitter circuit comprising a plurality of light emitters arranged on an inner face of the mask and configured to emit light inwards towards a skin surface of a user when wearing the mask; a transparent layer covering the light emitters; and, a plurality of lenses, each lens being integrally formed into the transparent layer and aligned with a respective light emitter of at least some of the plurality of light emitters. The transparent layer and its lenses protect the light emitters while simplifying manufacturing. Furthermore, the integrated lenses improve the control with which the light may be focused and / or disbursed. According to a fourth aspect, there comprises a flexible light-emitting mask, comprising: a light emitter circuit comprising a plurality of light emitters arranged on an inner face of the mask and configured to emit light towards a skin surface of a user when wearing the mask; and a reflective layer positioned behind the light emitters and in front of an outer face of the mask, the reflective layer being configured to reflect emitted light towards the skin of the user in use. In an embodiment the reflective layer comprises a metallic reflector coating a non-electrically conducting core. BRIEF DESCRIPTION OF THE DRAWINGS Examples of the present invention will now be described in detail with reference to the accompanying drawings, in which: Fig. 1 shows views of an exemplary face mask in a flattened configuration: Fig. 1A shows a front view, Fig. IB shows a top view, Fig. IC shows a side view, Fig. ID shows a first rear view, and Fig. IE shows an alternative rear view in which the back face of the mask has been removed; Fig. 2 shows views of an exemplary face mask in a face-mountable configuration. Fig. 2A shows a front perspective view, while Fig. 2B shows a rear perspective view; Fig. 3 shows a perspective view of an exemplary face mask in a front-torso-mountable configuration; Fig. 4 shows a perspective view of an exemplary face mask in a rear-torso-mountable configuration; Fig. 5 shows a perspective view of an exemplary face mask in a cranium-mountable configuration; Fig. 6 shows a perspective view of an exemplary face mask in a shoulder-mountable configuration; Fig. 7 shows a perspective view of an exemplary face mask in a knee-mountable configuration; Fig. 8 shows views of exemplary eye pads. Fig. 8A is a bottom view, Fig. 8B is a front view, Fig. 8C is a top view, Fig. 8D is a rear view, and Fig. 8E shows side views; Fig. 9 shows a rear view of a light-emitting circuit for an exemplary face mask; Fig. 10 shows a section of a rear view of an exemplary face mask including a reinforcing rib; Fig. 11 shows an exemplary transparent layer including an integral lens. Fig. 11(a) is a cross-section through an exemplary mask including the transparent layer, and Fig. 11(b) shows the cross-section of Fig. 11(a) in the context of a perspective view of the exemplary mask; and Fig. 12 is a diagram showing dispersal of light through an exemplary lens. DETAILED DESCRIPTION Fig. 1 illustrates a mask 100 according to the present disclosure. The mask 100 comprises an outer (i.e. front) face 4 and an inner (i.e. back) face 2, and a peripheral wall 8. The mask 100 is illustrated in a flattened configuration (i.e. with the inner face 2 and outer face 4 both substantially being flat). In this configuration, the mask 100 may be easily assembled, stored, or transported. The mask 100 may also be used on a flat part of the body in this flattened configuration, such as on the lower back. A light emitter circuit, comprising a plurality of light emitters 10, is arranged on the inner face 2 of the mask 100. In the illustrated example, the inner face 2 of the mask 100 comprises transparent silicone, as will be discussed in more detail in relation to Fig. 11, and the outer face 4 of the mask 100 comprises a non-transparent silicone. Silicone is strong, tough, flexible and can easily be cleaned and / or sterilised. Furthermore, silicone is non-conductive (thereby preventing any possibility of electrical shorting), can be configured into any required colour and can be easily printed on. In some examples, materials other than silicone may be used for the inner and / or outer faces. As discussed in more detail in relation to Fig. 11, the material selected for the inner face 2 may be at least partially transparent in order to facilitate the transmission of light. Examples of suitable alternative materials include thermoplastic elastomers (TPEs), rubber, urethane, flexible plastics, and also non-plastic materials such as foam or fabric. In some examples, the opacity of the material of the inner face 2 may be selected such that a balance is achieved between light transmission from the light emitters to the user, and aesthetics. For example, an entirely transparent inner face 2 may not be desirable as the underlying electronics may not be aesthetically pleasing. Furthermore, increased opacity may help to conceal other aesthetically unpleasant features, such as scratches or imperfections beneath the surface. However, a fully opaque inner face 2 would inhibit transmission of light from the light emitters to the user. Therefore, an appropriate opacity may be selected in order to balance these considerations. In some examples, the inner face 2 may have an opacity of around 10%. In examples where a flexible plastic type material, such as silicone, is used for the inner mask 2, the surface roughness of the inner surface of the inner face 2 of the mask may be varied. This is beneficial, since a smooth surface can provide optimal light transmission through the inner face 2, however a smooth surface can be uncomfortable to a user, since it can stick to a users skin in use. In some examples, the inner surface may be configured to be smooth and shiny in the regions adjacent to light emitters in order to maximize light transmission from the light emitters, while the roughness of the inner surface is increased in other areas in order to improve user comfort. In some examples, as discussed in more detail below, the mask may be configured such that, in use, the lower portion of the mask does not make contact with the user's skin. In such examples, the increased surface roughness may only be located in areas where, in use, contact with the user's skin is expected, such as the upper portion of the mask. A pair of openings (or "eye holes") 6 are located laterally either side of a mask nose region 30. When in use on the face, these eye holes 6 are configured to be substantially aligned with the eyes of a user, thereby allowing the user to see through the mask 100 when it is placed on the face. In some examples, the eye holes 6 may also prevent excessive light from being directed into the user's eyes during use. In the illustrated flattened configuration, the mask 100 may not comprise spacer pads (discussed in more detail below). The mask comprises a mouth hole 14 allows access to the user's mouth when the mask 100 is worn as a face mask, and helps to ensure that the user is able to breath freely while using the face mask. In the illustrated example, the mouth hole 14 is small. The small mouth hole allows for an increased density of light emitters around the mouth and lips of the user, and minimises the region that is unable to be treated due to the presence of the mouth hole 14 (which does not contain any light emitters). This is advantageous as it allows for light treatment to be specifically directed towards these areas, and also minimises the gap in light treatment that can be delivered when the mask is used on other parts of the body. A pair of slits 20 divide the mask into an upper mask region 11 and lower mask region 12, the upper mask region 11 and lower mask region 12 being joined through the mask nose region 30. Each slit 20 extends laterally (that is, along the left-right lateral axis when the mask 100 is worn on the face), from the edge of one of the eye holes 6 to the adjacent peripheral edge 8 of the mask 100. In the flattened configuration illustrated in Fig. 1, each slit 20 has opposing sides which define an elongate opening, that is, each slit is elongate relative to its length. In some examples, each slit may have a maximum width of between 0.1 mm and 20 mm. In some examples, the width may be between 0.5 mm and 10 mm when the mask is arranged in the flattened configuration. In other examples, the slits may have substantially zero width. This may be achieved by cutting the slits using laser or hot-wire cutting methods, or similar, where the cutting member cuts material but does not remove material. Alternatively, or additionally, the mask may be constructed such that removal of material to form a slit leaves substantially no separation in the flattened state (for example, by forming the mask in a non-planar shape that is released into a flat configuration by cutting the slits). In some examples, the width of the slits may be equal to, or less than, or more than the width of the respective eye hole from which they extend. In the illustrated example, the slits 20 are curved to smoothly join the eye holes 6. A typical eye hole shape has a sharp corner at the laterally outer edge of the eye hole, reflecting the anatomy of a human eye. This sharp corner may act as a stress concentrator, increasing the risk of tearing. To mitigate this problem, each slit 20 joins an eye holes 6 at the laterally outermost edge of the eye hole 6. This removes the sharp corner and reduces the likelihood of the mask 100 tearing. The slits 20 mean that the upper mask region 11 and lower mask region 12 are only joined together through the mask nose region 30. Specifically, the upper mask region 11 is joined to the mask nose region 30 only between the eye holes 6. The thinness of this connection which extends laterally only between the laterally inner sides of the eye holes, enables the upper mask region 11 and lower mask region 12 to be easily foldable relative to each other around a folding axis Fl extending laterally through the nose region 30. To further increase flexibility, the lower mask region is joined only to the mask nose region 30 only through the thin cheek bridges 36 beneath the eye holes 6. The upper mask region 11 and / or lower mask region 12 may also be foldable or otherwise flexible around a secondary folding axis F2, which extends perpendicular to the folding axis Fl within the plane of the mask 100 in the flattened configuration. For example, the upper and lower mask regions 11, 12 may be made of flexible materials which can be curved around the secondary axis F2. A reinforcing wall or other element may be extend fully or partially around the peripheral edge 8, increasing the strength and / or toughness of the mask 100 and providing an accessible region onto which components such as the retaining system 40, attachment rails 52 etc may be attached or formed. The mask nose region further comprises a nose cover 32, and a nose slit 34 separating the nose cover 32 from the lower mask region 12. The nose slit 34 also allows airflow through the mask to the user's nose, in use. The nose slit 34 is shaped to maximise the width of the cheek bridge 36 underneath each eye hole 6. This provides space for the electrical connectors (not shown) to run between the upper mask region 11 and lower mask region 12, without impeding the mouth hole 14 or nose slit 34. In some examples the upper mask region 11 and the lower mask region 12 are connected by one or more electrical connectors that are disposed in the nose region. In some examples, the one or more electrical connectors may comprise one or more wires. In some examples, as described in more detail below, the upper mask region 11 and lower mask region 12 may be formed from a single continuous PCB extending through the nose region. In such examples, the PCB itself comprises the electrical connector. In some examples, one or more of the electrical connectors may be disposed in a location other than the nose region. For example, an electrical connector may comprise a wire connecting the upper mask region 11 and the lower mask region 12, but not extending through the nose region. In such examples, such a wire may be disposed in any other suitable location, such as at a periphery of the mask. In some examples, one or more electrical connectors that do not pass through the nose region may be integrated with another component, such as an adjustable body strap (not shown). A retaining system 40 comprises an engagement member 44 on the lower mask region 12 in the form of a socket, and a plurality of retaining points 42 in the form of studs 42 on the upper mask region 11, each stud being configured to fit into and retain the engagement member 44 while allowing rotation of the stud within the socket. In fact, the upper mask region 11 comprises a plurality of retaining points 42A-C on each lateral side of the mask 100. A first retaining point 42A is located proximal to the slit 20 towards the folding axis Fl, and a second retaining point 42B is located distally to the slit 20, towards the top edge of the mask and away from the folding axis Fl. A third retaining point 42C is located between the first and second retaining points 42A, 42B on each lateral side of the mask 100. In the flattened configuration, the engagement members 44 are not retained at any of the retaining points 42. While a stud-and-socket arrangement is shown, it will be understood that other retaining systems are envisaged. For example, the engagement member and retaining points may comprise buttons, clasps, magnets, or other such devices which may be releasably attached and detached. The retaining system 40 may also comprise systems such as sliders or straps which can be releasably engaged over a continuum of retaining points. An attachment system is provided in the form of rails 52 around the peripheral edge for attaching an adjustable body strap (not shown) thereto. A illustrated in Figs. IB and IC, the mask 100 is thin in the flattened configuration relative to its lateral width and height. This reduces the bending stiffness of the mask 100, allowing it to be more easily folded or otherwise contoured into different geometries. Fig. ID illustrates a first rear view of the mask 100, showing the rear face 2 in position. Fig. IE shows an alternative rear view of the mask 100 in which the rear face 2 has been removed. This allows the lattice 18, which extends between the front face 4 and rear face 2, to be seen. The lattice comprises a plurality of walls 18A defining a plurality of cells 18B, with each cell encompassing a light emitter 10 to prevent light from that emitter from bounding around within the mask 100 between the rear face 2 and front face 4. In this example, each light emitter 10 on the mask 100 is encompassed individually within a cell 18B, but alternate arrangements of multi-emitter cells are also envisioned. Figs. 2-7 illustrate how the mask 100 of Fig. 1 may be configured and retained into alternate geometries. The same reference numerals are used to show the components as are used to label Fig. 1. The mask 100 is freely configurable between each of these geometries, such that the mask 100 may first assume a first geometry in which the upper mask region 11 and lower mask region 12 are folded relative to each other to achieve a first predetermined angular separation therebetween at the mask nose region 30 to provide a mask 100 that can be worn on a user's face. The mask 100 may also assume a second geometry in which the upper mask region 11 and lower mask region 12 are folded relative to each other to achieve a second predetermined angular separation therebetween at the mask nose region 30 to provide a mask 100 that can be worn on one or more different parts of the body of the user, which may (as shown below) be selected from at least the cranium, torso, back, neck, shoulder, knee, and elbow. In Fig. 2, the 100 mask is configured into a face-mountable configuration (i.e. the first geometry). The engagement members 44 on the lower mask region 12 are retained at the corresponding first retaining point 42A on the upper mask region 11. This causes the upper mask region 11 to fold relative to the lower mask region 12 around the folding axis F extending laterally through the nose region 30. Since the first retaining point 42A is proximal to the slit 20, the folding angle al around the folding axis Fl between the upper mask region 11 and lower mask region 12 is small, that is, small compared to other configurations which will be discussed below. In the face-mountable configuration, the lower mask region 12 overlaps with the upper mask region 11, such that the lower edge 22 of each slit 20 (i.e. the upper edge of the lower mask region 12) is visible from the front side of the mask 100, and the upper edge 21 of each slit 20 (i.e. the lower edge of the upper mask region 11) is visible from the rear side of the mask 100. The nose slits 34 and nose cover 32 are formed such that the folding of the upper and lower mask regions 11, 12 about the folding axis Fl causes the size of the nose slits 34 to increase, thereby providing more airflow to the user's nose. Fig. 2A also illustrates further features of the mask 100 not shown in Fig. 1, in particular the body strap 50, eye pads 60, cable 80 and external unit 82. A removably attachable spacer pad 60 in the form of an eye pad is disposed on the inner face 2 of the mask 100 and extends to the outer face 4 of the mask 100 around at least a portion (in this example, the entirety) of the periphery of each eye hole 6. The spacer pads 60 comprise spacers 64, with cushions 62 provided at a distal, inner end of each spacer 64. The cushions 62 bear against the user's cheeks and brows in use, blocking light from the emitters 10 from entering the user's eyes and providing a support for the mask 100 which can comfortably transfer forces between the mask and the user. The spacers 64 space the mask 100 from the user's skin by separating the user's skin from the attachment point between the mask 100 and the spacer pads 60, allowing airflow to circulate between the user's skin and the mask 100. In this example, the spacer pads 60 also form part of the retaining system 40, because they assist in retaining the mask 100 in the desired geometry. Specifically, the eye masks 60 attach to the mask 100 and control the curvature of the upper mask region 11 and lower mask region 12 such that they curve around a secondary folding axis F2 extending perpendicular to the folding axis Fl. The flexibility of the mask 100 is thus constrained along two axes Fl, F2 such that the mask 100 is optimally shaped for the contours of a user's face. The manner in which the eye pads 60 attach to the mask 100 so as to cause the upper mask region 11 and lower mask region 12 to curve will be explained in more detail in relation Fig. 8. An adjustable body strap 54 may be attached to the rails 52 and may be used for releasably attaching the mask to the user. The body strap 50 and rails 52 together form the attachment system 50. In the face-mountable configuration, the body strap 50 may be worn about the user's head, in the manner of a conventional head strap. The body strap 54 may comprise an adjustment system for accommodating different head sizes, and for allowing the body strap 54 to attach around different body parts. In this example, the adjustment system is provided by dividing the body strap 54 into two halves which can be attached at different points along their length, e.g. by using buttons, Velcro, or other attachment means. Hence, the face-mountable configuration (i.e. the first geometry) may be variably adjusted for different user body sizes. The face-mountable configuration may also be adjusted for different user body sizes by retaining the engagement members 44 at the third retaining point 42C rather than the first engagement point 42A. Since the third retaining point 42C is located slightly further away from the slits 20, this would cause the upper mask region 11 to be folded slightly more around the folding axis Fl relative to the lower mask region 12, thereby slightly increasing the folding angle al. The larger folding angle al makes the mask 100 more suitable for smaller head sizes. The cable 80 leads to an external unit 82. The external unit 82 may comprise a power source 84 such as a battery, for powering the light emitters of the mask 100. The external unit 82 may further comprise a user input device 86 for controlling an emission program of at least some of the plurality of light emitters 10 of the mask 100. The user input device 86 may also be connected via a wireless connection and may be integrated into an external computing device, such as a smartphone, using conventional means. In Fig. 3, the mask 100 is configured into a torso-mountable configuration (an exemplary second geometry), specifically a front-torso-mountable configuration. To achieve this configuration, the engagement members 44 are detached from any of the retaining points 42. The upper mask region llcan then be folded away from the lower mask region 12 around the folding axis Fl, such that the folding angle al is now in the opposite direction compared to the face-mountable configuration. The mask 100 is now configured so that the lower mask region 12 sits over the front torso (e.g. chest, breasts) of the user 1, while the upper mask region 11 sits over the front of the user's neck. The flexible nose bridge region 32 allows the upper and lower mask regions 11, 12 to fold relative to each other in use, such as when the user 1 lowers or raises their head by nodding. This provides additional comfort to the user 1 as they are wearing the mask 100. The mask 100 may be attached to the user 1 by attaching the attachment strap 54 around the user's neck. Tightening the attachment strap 54 using the strap length adjustment system may cause the curvature of the upper mask region 11 to increase around the vertical secondary folding axis F2, allowing the upper mask region 11 to curve about the neck of the user 1. The lower mask region 12, however, remains substantially uncurved around the secondary folding axis F2. In this configuration, the spacer pads 60 are not required to protect the user's eyes and have therefore been detached from the mask 100. In Fig. 4, the mask 100 is configured into a rear-torso-mountable configuration. This configuration is substantially the same as the front-torso-mountable configuration, except that the mask 100 is configured such that the lower mask region 12 sits over the upper back of the user 1, while the upper mask region 11 sits over the rear of the user's neck. When the user has a normal upright posture, there is only a small or even zero folding angle al around the folding axis Fl. Of course, this folding angle al can change as the user 1 moves their head. As with the front-torso-mountable configuration, the body strap 54 may be fastened around the neck of the user 1, and may be used to change the curvature of the upper mask region 11 around the secondary folding axis F2. In Fig. 5, the mask 100 is configured into a cranium-mountable configuration. In this configuration, the mask 100 may be worn over the top of the head of the user 1. In the example shown, the mask 100 is positioned primarily over the front of top of the head, allowing the mask 100 to emit light over the forehead and front part of the scalp / hair of the user 1. The mask 100 may also be positioned further towards the rear of the head of the user 1, in the manner of a skullcap, so that light may be emitted over the rear part of the scalp / hair of the user 1. To configure the mask 100 into the cranium-mountable configuration, the retaining system 40 is configured such that the engagement members 44 are retained at the second retaining point 42B. Since the second retaining point is distal from the slits 20 and the folding axis Fl, this causes the upper mask region 11 to fold substantially relative to the lower mask region 12, such that the folding angle al around the folding axis Fl is large (that is, large as compared to in other configurations such as the face-mountable configuration of Fig. 2). The increased folding of the mask 100 allows the mask to follow and be worn over the top of the head of a user 1. The body strap 54 may be used to help attach the mask 100 to the user's head in this configuration, for example by attaching the body strap behind the ears as shown in Fig. 1 or alternatively under the chin in the manner of a helmet. In Fig. 6, the mask 100 is configured in a shoulder-mountable configuration. This configuration is substantially the same as the cranium-mountable configuration, except that that the body strap 54 has been replaced with a different attachment mount (which is hidden behind the mask) for attaching the mask 100 around the shoulder. Such a mount may for example comprise suction mounts, an adhesive, or a different strap arrangement. As with the cranium-mountable configuration, the increased folding of the mask 100 allows the mask to follow and be worn over the curves of the shoulder of a user 1. In some examples, the mask may be configured to be attachable to a user using any suitable means. For example, as described above, the mask may comprise an attachable body strap configured to attach and retain the mask in a position on a user's body. In some examples, such a strap (or other attachment means) may comprise the same material as the mask and may, in some examples, be formed integrally with the mask. In some examples, the mask may alternatively, or additionally, be configured to be attachable with one or more external components such as a band, a strap or even an item of clothing such as a hat. In such examples, the one or more external components may be designed specifically for use with the mask. In further examples, the mask may be configured such that it is compatible with external components that are not specifically designed for use with the mask, such as a generic item of clothing (e.g., a hat to secure the mask on a wearer's head, a sock to retain the mask on a user's ankle, or tuba grip to hold to the users knee). In Fig. 7, the mask 100 is configured in a shoulder-mountable configuration. This configuration is substantially the same as the cranium-mountable configuration, except that that the body strap 54 has been attached around the leg behind the knee to retain the mask 100 over the knee of the user. The retaining system 40 may be configured to allow a degree of folding between the upper and lower mask regions 11, 12 even when the engagement member 44 is retained at a retaining point 42. For example, as previously mentioned the engagement member 44 may comprise a stud which is retained by a retaining point 42 in in the form of a socket which allows a degree of rotation of the stud relative to the socket while retained. This allows the upper mask region 11 to rotate and / or flex relative to the lower mask region 12, accommodating movements of the user 1 (such as movements of the arm in the shoulder-mountable configuration or movements of the leg in the knee-mountable configuration) and increasing the comfort of the mask 100 when worn in configurations such as the shoulder-or knee- mountable configuration. Fig. 8 shows an exemplary pair of spacer pads in the form of eye pads 600, which may be removably attached to an exemplary mask such as the mask 100 as previously described. Different eye pads 600 may be provided with the mask 100, so that the user can select the eye pad which is most comfortable for them based on their head size and / or other preferences. Each eye pad 600 comprises a cushion 602, which may be made of a pliable material, such as foam. The cushion 602 may be shaped for resting against the brow, temple, nose bone and / or cheek bone of the user in use, so that forces may be comfortably transmitted between the mask 100 and the head of a user. The cushion is positioned at the distal end of a spacer 604. At the other end of the spacer 604 are provided an upper attachment point 611 for attaching to the upper mask region 11 and a lower attachment point 612 for attaching to the lower mask region 12. The spacer 604 spaces the user's skin (in contact with the cushion 602) from the mask 100 (in contact with the attachment points). To provide sufficient room for airflow circulation between the mask 100 and the user's skin, the spacer 604 may be between 1 and 40 mm in length. The attachment points 611, 612 may be configured to provide an interference fit with the mask 100, such that the eye pad 600 is positively retained to the mask 100. In addition, the attachment points 611, 612 may each be shaped so as to retain their respective mask region 11, 12 into a particular geometry. In this example, the attachment points 611, 612 are angled and / or curved relative to the plane of the face. When a pair of eye pads 600 are attached to the mask 100, the shape of the upper attachment points 611 cause the upper mask region 11 to curve along the curve 611A, and the shape of the lower attachment points 612 cause the lower mask region 12 to curve along the curve 612A. Additionally in this example, as best shown by Fig. 8E, the lower attachment point 612 is positioned further forwards (i.e. away from the spacer 604 and cushion 602) than the upper attachment point 611. Thus when the eye mask 600 is attached to a mask 100, the lower mask region 12 overlaps the upper mask region 11 when viewed from the front. An eye hole 606 allows the user to see through the eye pad 600. A visual indicator 608 may also be provided to assist the user in correctly selecting and orienting an eye pad 600 for attachment to the mask 100. Without the indicator 608, a user may inadvertently attach the eye pads 600 the wrong way round and / or the wrong way up. Fig. 9 shows a light emitter circuit 900 for use within an exemplary mask, such as the mask 100 previously described. In this example, the light emitter circuit comprises a flexible, single-piece PCB, which serves as both the circuit and the circuit support substrate. Other light emitter circuit configurations may also be used, such as simply routing individual wires in a bundle or loom. The light emitter circuit 910 may be divided into an upper light emitter circuit 911 comprising a first array of light emitters 910, and a lower light emitter circuit 912 comprising a second array of light emitters 910. The upper light emitter circuit 911 may be contained within the upper mask region 11 of the mask 100, and the lower light emitter 912 may be contained within the lower mask region 12 of the mask. The upper and lower emitter circuits are separated by a slit 920 and eye holes 906 which correspond to the geometry of the slits 20 and eye holes 6 in the inner face 2 and outer face 4 of the mask 100. The nose region 930 of the light emitter circuit 900 connects to the upper light emitter circuit 911 only in the space between the eye holes 906. This area has a small crosssection and hence low bending stiffness, thereby allowing the nose region 930 to function as a flexible electrical connector between the upper and lower light emitter circuits 611, 612. To further increase flexibility, the nose region 930 is connected to the lower light emitter circuit 912 only through cheek bridges 936 below the eye holes 906, which also have a small area and cross section. To prevent the thin nose region 930 from tearing or over-bending, nose reinforcement members 990, 996 are provided for reinforcing the mask nose region 930. The main nose reinforcement member 990 reinforces the region between the eye holes 906, and the cheek bridge reinforcement members reinforce the cheek bridges 936. In this example, the reinforcement members 990, 996 are attached to the circuit support substrate (i.e. the body of the flexible PCB) by integrally forming the reinforcement members 990, 996 as part of the PCB manufacturing process. Although in the illustrated example the reinforcement members 990, 996, are formed integrally with the PCB, it should be understood that alternative examples are contemplated. For example, a reinforcement member may additionally, or alternatively, be formed integrally with other components of the mask (as discussed below in relation to figure 10) and / or as a non-integral component. Such a reinforcement member may be attached / bonded to the PCB, or may simply be arranged next to the PCB in order to provide additional stiffness to the nose region. In some examples, the reinforcement member may comprise reinforced tape, such as fibre tape, bonded to the PCB. Each of the upper and lower light emitter circuits comprises a plurality of light emitters 910 in the form of LEDs. Each light emitter 910 may comprise one or more subemitters. For example, a light emitter 910 may comprise a red, blue, green and nearinfrared sub-emitter, such that the light emitter 910 can emit light at multiple wavelengths. Fig. 10 shows a rear view of an alternative exemplary mask 1000. The mask 1000 comprises a plurality of light emitters 1010 and is divided into an upper mask region 1011 and a lower mask region 1012 by a pair of eye holes 1006. The rear face 1002 of the mask 1000 is transparent and covers the light emitters 1010, allowing the interior of the mask 1000 to be seen. In this example, a reinforcement member 1090 in the form of a pair of reinforcing ribs, each rib extending between the upper mask region 1011 and lower mask region 1012 through the mask nose region 1030 and a mask cheek bridge 1036. The reinforcement member controls the flexibility of the mask 1000 and prevents tearing or over-bending of the mask nose region 1030. In this example, the nose reinforcement member is integrally formed with the front face of the mask 1000 and is made of silicone. In other examples, the reinforcing rib may additionally or alternatively be made from silicone, plastic, metal, composite, gel, or combinations thereof. Fig. 11(a) and 11(b) show cross-sections through an exemplary mask 1100, which may be the exemplary mask 100 previously described or a different exemplary mask. The mask 1100 comprises a plurality of light emitters 1110, which are arranged on a flexible light emitting circuit 1190 such as a flexible PCB. The light emitting circuit 1190 may be mounted on or integrally formed with the front, outer layer 1104 of the mask 1100, which may be formed of a flexible but non-transparent material. The inner, rear face of the mask comprises a transparent layer 1102 covering the light emitters 1110. The transparent layer 1102 comprises a plurality of lenses 1170, each lens 1170 being integrally formed into the transparent layer 1102 and aligned with a respective light emitter 1110. The transparent layer and in particular the lenses 1170 serve to protect the light emitter 1110 and prevent the light emitter from coming directly into contact with a user's skin. In the vicinity of a lens 1170, the transparent layer 1102 comprises an emitter-facing side facing (i.e. proximal towards) the plurality of light emitters 1110, and an opposing face opposite the emitter-facing side. In this example, the transparent layer 1102 forms the inner surface of the mask 1100, such that the opposing face is the innermost face of the mask 1100. However, it is also envisioned that the transparent layer 1102 is not the inner face of the mask 1100, and may instead form an intermediate layer between the light emitters 1110 and the inner surface of the mask. An internal support wall 1118, which may form part of a larger support lattice, allows the rear face 1102 to bear against the front face 1104 and may redirect internal reflection within the mask 1100 towards the user's skin. In this example, each lens 1170 comprises a dispersing lens in the form of a meniscus lens, configured to disperse light from the light emitters 1110 over a wider area of the user's skin. Each lens 1170 is defined by a concave segment 1174 on the emitterfacing side 1170 and a convex segment 1172 on the opposing side, the convex segment 1172 having a larger radius than the concave segment 1174. As shown by Figure 12, such an arrangement causes light from the emitters 1110 to be dispersed. Some or all lenses 1170 may alternatively comprise focusing lenses. Such lenses may also be configured with a concave segment on the emitter-facing side and a convex segment on the opposing side, but the convex segment instead has a smaller radius than the concave segment. Although not shown in the illustration, in some examples the surface roughness of the inner surface of the mask 1100 may be varied in order to provide improved light transmission and also improved comfort to the user. In some examples, the plurality of lenses 1170 have a low surface roughness in order to maximise light transmission, while other areas of the inner surface of the mask 1100 have an increased surface roughness in order to improve user comfort. As discussed previously, in some examples the mask 1100 is configured such that, in use, the lower portion of the mask does not make contact with a users skin (for example, where spacer pads are used). In such example, the mask 1100 may be configured such that only the upper portion of the inner surface of the mask 1100 (in areas that do not comprise lenses 1170) has increased roughness. The roughness may also be varied in other areas for reasons or comfort or functionality, such as around the lips or eye brows or around the eyes. The face mask 1100 further comprises a reflective layer 1108 positioned behind the light emitters 1100 away from the transparent layer 1102 and inner face of the mask 1100. The reflective layer 1108 is configured to reflect emitted light towards the skin of the user in use, in particular to re-reflect light previously reflected from the user's skin or the interior of the mask 110 back inwards towards the user's skin. This increases the effectiveness of the mask 1100, by improving light coverage and reducing absorption of light by the mask 1100 (which can cause the mask to heat up uncomfortably). The reflective layer 1108 may comprise a specular reflector, such as a metallic reflector. A specular reflector reflects incident light rays LR coherently in a single direction, rather than being dispersed in all directions as a diffuse reflector would. This ensures that incident light rays LR. on the reflective layer (which are primarily reflections from the user's skin) are reflected back inwards towards the user's skin. The metallic reflector may be a thin coating on a non-electrically conductive (e.g. plastic or silicone) core, so that the specular reflector has a high overall electrical resistance and is less likely to cause short circuits. Fig. 12 shows an exemplary dispersing lens 1270 positioned in front of a light emitter 1210. The light emitter 1210 is effectively a point source, emitting light rays LR from a single small point of emission. The lens 1270 is formed in a layer of transparent material 1202. The lens 1270 is defined by a concave segment 1274 on the emitterfacing side 1270 and a convex segment 1272 on the opposing side, the convex segment 1272 having a larger radius than the concave segment 1274. This arrangement causes light rays LR from the emitters 1110 to be dispersed. An alternative arrangement in which the light rays LR are focused rather than dispersed may be provided if the convex segment 1272 has a smaller radius than the concave segment 1274. Further examples It should be understood that the illustrated devices disclosed herein are merely exemplary, and the devices could potentially be provided with additional or fewer features whilst still falling within the scope of the appended claims. Likewise, the shapes and sizes of the components of the devices could differ from those illustrated. In addition, unless specified otherwise, the order in which the method steps are presented is merely exemplary, and one skilled in the art will recognise that the steps of the methods disclosed herein could be performed in a different order (unless technically infeasible) and that additional or fewer steps could also be performed. The following numbered paragraphs represent further examples of a face mask according to the invention: 1. A flexible light-emitting face mask comprising: a light emitter circuit comprising a plurality of light emitters arranged on an inner face of the mask and configured in use to emit light towards a skin surface of a user when wearing the mask; a transparent layer covering the light emitters; and, a plurality of lenses, each lens being integrally formed into the transparent layer and aligned with a respective light emitter of at least some of the plurality of light emitters. 2. The face mask of paragraph 1, wherein at least one of the plurality of lenses comprises a dispersing lens. 3. The face mask of paragraphs 2 or 3, wherein the transparent layer comprises: an emitter-facing side facing the plurality of light emitters; and an opposing face opposite the emitter-facing side; and wherein at least one lens comprises a meniscus lens defined by a concave segment on the emitter-facing side and a convex segment on the opposing side, the convex segment having a larger radius than the concave segment. 4. The face mask of paragraphs 2 or 3, wherein each lens comprises: a meniscus lens defined by a concave segment on the emitter-facing side and a convex segment on the opposing side, the convex segment having a larger radius than the concave segment; and / or a dispersing lens. 5. The face mask according to any preceding paragraph, further comprising a reflective layer positioned behind the light emitters away from the inner face of the mask, the reflective layer being configured to reflect emitted light towards the skin of the user in use. 6. The face mask of paragraph 5, wherein the reflective layer comprises a specular reflector. 7. The face mask of paragraphs 5 or 6, wherein the reflector comprises a metallic reflector coating a non-electrically conductive core. 8. The face mask of any preceding paragraph, wherein the transparent layer comprises: an emitter-facing side facing the plurality of light emitters; and an opposing face opposite the emitter-facing side; and wherein the opposing face has a variable surface roughness. 9. The face mask of paragraph 8, wherein the opposing face comprises one or more areas with a lower surface roughness arranged adjacent to a light emitter. 10. The face mask of paragraph 9, wherein, in use, the areas with lower surface roughness are arranged to transmit light from a light emitter. 11. The face mask of paragraphs 9 or 10, wherein the opposing face comprises a higher surface roughness in one or more areas that, in use, are not configured to transmit light from a light emitter. 12. The face mask of any of paragraphs 8 to 11, wherein the face mask has a higher surface roughness in areas that, in use, are in contact with the skin surface of a user. 13. The mask of any preceding paragraph, further comprising: a pair of openings located laterally either side of a mask nose region; and, a pair of slits dividing the mask into an upper mask region and lower mask region joined through the mask nose region, each slit extending laterally from one of the openings to a peripheral edge of the mask, wherein the upper mask region and lower mask region are foldable relative to each other around a folding axis extending laterally through the nose region. 14. The face mask of paragraph 13, wherein the light emitter circuit comprises: an upper light emitter circuit in the upper mask region having a first array of light emitters; a lower light emitter circuit in the lower mask region having a second array of light emitters; and, an electrical connector connecting together the upper circuit and the lower circuit, and optionally the electrical connector extends through a cheek bridge connecting the mask nose region to a cheek region of the lower mask region. 15. The face mask of paragraph 14, wherein the electrical connector extends through the mask nose region. 16. The face mask of any preceding paragraph, further comprising at least one controller for controlling the light emitters. 17. The face mask of paragraph 16, wherein the controller is adapted to receive an emission program for at least some of the light emitters and, optionally, wherein the controller is adapted to control at least one of: an emission wavelength; an emission duration; an emission pulse width; or an emission mask pattern in response to the emission program. 18. The face mask of any preceding paragraph, wherein each slit has opposing sides which define an elongate opening. 19. The face mask of any preceding paragraph, wherein the slits define an elongate opening having a width of between 0.1 mm and 20 mm and, optionally, between 0.5 mm and 10 mm. 20. The face mask of any preceding paragraph, further comprising a nose reinforcement member for reinforcing the mask nose region. 21. The face mask of any preceding paragraph, further comprising at least one spacer pad on the inner face of the mask. 22. The face mask of paragraph 21, wherein the spacer pads are removably attachable to the mask. 23. The face mask of paragraph 21 or 22, wherein the at least one spacer pad comprises a pair of pads around at least a portion of the periphery of each opening. 24. A kit of parts, comprising: the face mask of any preceding paragraph; and, a power source for the face mask. 25. The kit of paragraph 24, further comprising a user input device for controlling an emission program of at least some of the plurality of light emitters. According to an aspect, there is provided a flexible light-emitting face mask comprising: a light emitter circuit comprising a plurality of light emitters arranged on an inner face of the mask and configured in use to emit light towards a skin surface of a user when wearing the mask; a transparent layer covering the light emitters; and, a plurality of lenses, each lens being integrally formed into the transparent layer and aligned with a respective light emitter of at least some of the plurality of light emitters. Lenses allow for light emitted by the light emitters to be more accurately directed. For example, when the mask is in use on a user's face, the lenses may allow for light to be more evenly distributed across the user's skin. Also, lenses may allow for light to be focussed more accurately. By integrating the lenses directly into the transparent layer, the mask can precisely focus light from each emitter onto the skin. This ensures that the therapeutic light is delivered exactly where it is needed, improving the effectiveness of the treatment. Integrating the lenses into the transparent layer reduces the need for additional components or attachments. This results in a more compact and streamlined design, making the mask lighter and more comfortable for the user. The integrated design also minimises the risk of lenses becoming dislodged or misaligned during use. This enhances the durability and reliability of the mask, ensuring consistent performance over time. The integration allows for a more uniform distribution of light across the skin surface. This can lead to more consistent therapeutic outcomes, as the light is evenly dispersed and / or focused as needed. In an embodiment, at least one of the plurality of lenses comprises a dispersing lens. The inclusion of dispersing lenses allows for a more uniform distribution of light, improving the overall effectiveness of the therapy. In an embodiment, the transparent layer comprises: an emitter-facing side facing the plurality of light emitters; and an opposing face opposite the emitter-facing side; and wherein at least one lens comprises a meniscus lens defined by a concave segment on the emitter-facing side and a convex segment on the opposing side, the convex segment having a larger radius than the concave segment. The meniscus lens design optimizes light focus and dispersion, enhancing the precision and effectiveness of the light therapy. In an embodiment, each lens comprises: a meniscus lens defined by a concave segment on the emitter-facing side and a convex segment on the opposing side, the convex segment having a larger radius than the concave segment; and / or a dispersing lens. Meniscus and dispersing lenses each provide advantages and ensuring that each lens is at least one of these two options allows for optimal light delivery. In an embodiment, the face mask further comprises a reflective layer positioned behind the light emitters away from the inner face of the mask, the reflective layer being configured to reflect emitted light towards the skin of the user in use. The reflective layer maximizes light utilization by redirecting emitted light towards the skin, increasing treatment efficiency. Furthermore, the reflective layer may allow for lower energy usage, thereby improving the power efficiency and potentially reducing excess heat production. In an embodiment, the reflective layer comprises a specular reflector. A specular reflector ensures high reflectivity and precise light direction, enhancing the mask's therapeutic performance. In an embodiment, the reflector comprises a metallic reflector coating a non-electrically conductive core. The metallic reflector with a non-conductive core provides durability and safety, ensuring consistent light reflection without electrical interference. In an embodiment, the transparent layer comprises: an emitter-facing side facing the plurality of light emitters; and an opposing face opposite the emitter-facing side; and wherein the opposing face has a variable surface roughness. An increased surface roughness can improve the comfort of the mask to the user, by preventing the mask from becoming tacky and / or sticking to the user's skin in use. Reduced surface roughness allows for more efficient and precise light transmission through the transparent layer. By varying the surface roughness, both benefits can be realised in different areas of the mask. In an embodiment, the opposing face comprises one or more areas with a lower surface roughness arranged adjacent to a light emitter. Lower surface roughness areas adjacent to light emitters ensure maximum light transmission, improving the effectiveness of the therapy. In an embodiment, in use, the areas with lower surface roughness are arranged to transmit light from a light emitter. Lower surface roughness areas adjacent to light emitters ensure maximum light transmission, improving the effectiveness of the therapy. In an embodiment, the opposing face comprises a higher surface roughness in one or more areas that, in use, are not configured to transmit light from a light emitter. Higher surface roughness can improve the comfort of the mask to the user, by preventing the mask from becoming tacky and / or sticking to the user's skin in use. By increasing the surface roughness in areas that are not configured to transmit light, user comfort can be improved without reducing light transmission. In an embodiment, the face mask has a higher surface roughness in areas that, in use, are in contact with the skin surface of a user. Higher surface roughness can improve the comfort of the mask to the user, by preventing the mask from becoming tacky and / or sticking to the user's skin in use. By increasing the surface roughness in areas that are, in use, in contact with the user's skin, user comfort can be improved. In an embodiment, the face mask further comprises: a pair of openings located laterally either side of a mask nose region; and, a pair of slits dividing the mask into an upper mask region and lower mask region joined through the mask nose region, each slit extending laterally from one of the openings to a peripheral edge of the mask, wherein the upper mask region and lower mask region are foldable relative to each other around a folding axis extending laterally through the nose region. This foldable design allows for a better fit and improved flexibility, enhancing user comfort and light coverage. Furthermore, the foldable design and the pair of slits may allow for the mask to be adapted for use on body parts other than the face. In an embodiment, the light emitter circuit comprises: an upper light emitter circuit in the upper mask region having a first array of light emitters; a lower light emitter circuit in the lower mask region having a second array of light emitters; and, an electrical connector connecting together the upper circuit and the lower circuit, and optionally the electrical connector extends through a cheek bridge connecting the mask nose region to a cheek region of the lower mask region. Separate light emitter circuits for upper and lower mask regions enable targeted therapy, improving treatment customisation. The electrical connector allows for power and control to be shared between the upper and lower sections, thereby reducing the complexity of the device. In an embodiment, the electrical connector extends through the mask nose region. By extending through the nose region, the electrical connector can be secured and protected from potential damage. In an embodiment, the face mask comprises at least one controller for controlling the light emitters. The inclusion of a controller allows for precise control of light emission, enhancing the customization and effectiveness of the therapy. In an embodiment, the controller is adapted to receive an emission program for at least some of the light emitters and, optionally, wherein the controller is adapted to control at least one of: an emission wavelength; an emission duration; an emission pulse width; or an emission mask pattern in response to the emission program. The ability to receive and execute emission programs allows for tailored treatments, improving therapeutic outcomes. In an embodiment, each slit has opposing sides which define an elongate opening. The slit's elongate openings provide flexibility and adjustability, enhancing the mask's fit, comfort, and adaptability. In an embodiment, the slits define an elongate opening having a width of between 0.1 mm and 20 mm and, optionally, between 0.5 mm and 10 mm. These slit dimensions provide a good balance between providing flexibility and adjustability, while maximising the area in which light emitters can be placed. In an embodiment, the face mask further comprises a nose reinforcement member for reinforcing the mask nose region. A nose reinforcement member provides structural support, improving the stability and durability of the mask. In an embodiment, there is provided at least one spacer pad on the inner face of the mask. Spacer pads on the inner face enhance comfort and ensure proper light emitter positioning, improving treatment effectiveness. Furthermore, the spacer pads may reduce the area of the mask in direct contact with the user's face, thereby improving airflow under the mask and thus user comfort. In an embodiment, the spacer pads are removably attachable to the mask. Removably attachable spacer pads offer customization and ease of cleaning, enhancing user convenience. In an embodiment, the at least one spacer pad comprises a pair of pads around at least a portion of the periphery of each opening. Spacer pads around openings ensure a secure fit and prevent light leakage, improving the mask's therapeutic performance. According to another aspect, there is provided a kit of parts, comprising: the face mask of any preceding claim; and a power source for the face mask. In an embodiment, the kit of parts further comprises a user input device for controlling an emission program of at least some of the plurality of light emitters. A user input device for controlling emission programs allows for personalized treatments, improving user satisfaction and therapeutic outcomes.

Claims

1. A flexible light-emitting face mask comprising:a light emitter circuit comprising a plurality of light emitters arranged on an inner face of the mask and configured in use to emit light towards a skin surface of a user when wearing the mask;a pair of openings located laterally either side of a mask nose region; and,a pair of slits dividing the mask into an upper mask region and lower mask region joined through the mask nose region, each slit extending laterally from one of the openings to a peripheral edge of the mask,wherein the upper mask region and lower mask region are foldable relative to each other around a folding axis extending laterally through the nose region.

2. The face mask of claim 1, wherein the light emitter circuit comprises:an upper light emitter circuit in the upper mask region having a first array of light emitters;a lower light emitter circuit in the lower mask region having a second array of light emitters; and,an electrical connector connecting together the upper circuit and the lower circuit, and optionally the electrical connector extends through a cheek bridge connecting the mask nose region to a cheek region of the lower mask region.

3. The face mask of claim 2, wherein the electrical connector extends through the mask nose region.

4. The face mask of any preceding claim, further comprising at least one controller for controlling the light emitters.

5. The face mask of claim 4, wherein the controller is adapted to receive an emission program for at least some of the light emitters and, optionally, wherein the controller is adapted to control at least one of:an emission wavelength;an emission duration;an emission pulse width; oran emission mask patternin response to the emission program.

6. The face mask of any preceding claim, wherein each slit has opposing sides which define an elongate opening.

7. The face mask of any preceding claim, wherein the slits define an elongate opening having a width of between 0.1 mm and 20 mm and, optionally, between 0.5 mm and 10 mm.

8. The face mask of any preceding claim, further comprising a nose reinforcement member for reinforcing the mask nose region.

9. The face mask of claim 8, wherein the nose reinforcement member comprises a reinforcing rib and, optionally, wherein the nose reinforcement member comprises silicone, plastic, metal, composite, and / or gel.

10. The face mask of claims 8 or 9, further comprising a circuit support substrate for supporting the light emitter circuit,wherein the circuit support substrate comprises the reinforcement member, and optionally the reinforcement member is integrally formed with the circuit support.

11. The face mask of any preceding claim, further comprising a retaining system for configuring a geometry of the face mask selected from a set of predetermined geometries and, optionally, further comprising an attachment system for attaching the mask to the user.

12. The face mask of claim 11, wherein the set of predetermined geometries comprises:a first geometry in which the upper mask region and lower mask region are folded relative to each other to achieve a first predetermined angular separation therebetween at the mask nose region to provide a mask that can be worn on a user's face; and,a second geometry in which the upper mask region and lower mask region are folded relative to each other to achieve a second predetermined angular separation therebetween at the mask nose region to provide a mask that can be worn on one or more different parts of the body of the user and, optionally, wherein the one or more different parts of the body are selected from: the cranium, torso, back, neck, shoulder, knee, and elbow.

13. The face mask of claim 12, wherein the first geometry or second geometry can be variably adjusted to fit different user body sizes.

14. The face mask of any of claims 11 to 13, wherein the retaining system comprises an engagement member located on one of the lower mask region and the upper mask region and a first retaining point located on the other mask region, the engagement member being releasably engageable at the first retaining point.

15. The face mask of claim 14, further comprising a second retaining point, the first retaining point being located proximally to the slit and the second retaining point being located distally to the slit.

16. The face mask of any preceding claim, further comprising at least one spacer pad on the inner face of the mask.

17. The face mask of claim 16, wherein the spacer pads are removably attachable to the mask.

18. The face mask of claim 16 or 17, wherein the at least one spacer pad comprises a pair of pads around at least a portion of the periphery of each opening.

19. The face mask of any preceding claim, wherein the mask further comprises a lattice, the lattice comprising a plurality of walls defining a plurality of cells, wherein at least some of the cells each encompass a respective light emitter of the plurality of light emitters.

20. The face mask of any preceding claim, further comprising: a transparent layer covering the light emitters; and, a plurality of lenses, each lens being integrally formed into the transparent layer and aligned with a respective light emitter of at least some of the plurality of light emitters.

21. The face mask of claim 20, wherein each lens comprises a dispersing lens.

22. The face mask of claim 21, wherein the transparent layer comprises:an emitter-facing side facing the plurality of light emitters; and, an opposing face opposite the emitter-facing side, andwherein each lens comprises a meniscus lens defined by a concave segment on the emitter-facing side and a convex segment on the opposing side, the convex segment having a larger radius than the concave segment.

23. The face mask of any preceding claim, further comprising a reflective layer positioned behind the light emitters away from the inner face of the mask, the reflective layer being configured to reflect emitted light towards the skin of the user in use.

24. The face mask of claim 23, wherein the reflective layer comprises a specular reflector and, optionally, wherein the reflector comprises a metallic reflector coating a non-electrically conductive core.

25. A kit of parts, comprising:the face mask of any preceding claim; and,a power source for the face mask.

26. The kit of claim 25, further comprising a user input device for controlling an emission program of at least some of the plurality of light emitters.

27. A flexible light-emitting face mask comprising:a light emitter circuit comprising a plurality of light emitters arranged on an inner face of the mask and configured in use to emit light towards a skin surface of a user when wearing the mask; anda reflective layer positioned behind the light emitters away from the inner face of the mask, the reflective layer being configured to reflect emitted light towards the skin of the user, in use.

28. A flexible light-emitting face mask comprising:a light emitter circuit comprising a plurality of light emitters arranged on an inner face of the mask and configured in use to emit light towards a skin surface of a user when wearing the mask;a transparent layer covering the light emitters; and,a plurality of lenses, each lens being integrally formed into the transparent layer and aligned with a respective light emitter of at least some of the plurality of light emitters.15 1225CLAIMS1. A flexible light-emitting face mask comprising:a light emitter circuit comprising a plurality of light emitters arranged on an inner face of the mask and configured in use to emit light towards a skin surface of a user when wearing the mask;a pair of openings located laterally either side of a mask nose region;a pair of slits dividing the mask into an upper mask region and lower mask region joined through the mask nose region, each slit extending laterally from one of the openings to a peripheral edge of the mask,wherein the upper mask region and lower mask region are foldable relative to each other around a folding axis extending laterally through the nose region; anda retaining system comprising an engagement member located on one of the lower mask region and the upper mask region and a first retaining point located on the other mask region, the engagement member being releasably engageable at the first retaining point, the retaining system configured to:configure and hold the face mask in first geometry to provide a mask that can be worn on a user's face; andconfigure and hold the face mask in a second geometry to provide a mask that can be worn on one or more different parts of the body of the user other than the face.

2. The face mask of claim 1, wherein the light emitter circuit comprises:an upper light emitter circuit in the upper mask region having a first array of light emitters;a lower light emitter circuit in the lower mask region having a second array of light emitters; and,an electrical connector connecting together the upper circuit and the lower circuit, and optionally the electrical connector extends through a cheek bridge connecting the mask nose region to a cheek region of the lower mask region.

3. The face mask of claim 2, wherein the electrical connector extends through the mask nose region.

4. The face mask of any preceding claim, further comprising at least one controller for controlling the light emitters.15 12255. The face mask of claim 4, wherein the controller is adapted to receive an emission program for at least some of the light emitters and, optionally, wherein the controller is adapted to control at least one of:an emission wavelength;an emission duration;an emission pulse width; oran emission mask patternin response to the emission program.

6. The face mask of any preceding claim, wherein each slit has opposing sides which define an elongate opening.

7. The face mask of any preceding claim, wherein the slits define an elongate opening having a width of between 0.1 mm and 20 mm and, optionally, between 0.5 mm and 10 mm.

8. The face mask of any preceding claim, further comprising a nose reinforcement member for reinforcing the mask nose region.

9. The face mask of claim 8, wherein the nose reinforcement member comprises a reinforcing rib and, optionally, wherein the nose reinforcement member comprises silicone, plastic, metal, composite, and / or gel.

10. The face mask of claims 8 or 9, further comprising a circuit support substrate for supporting the light emitter circuit,wherein the circuit support substrate comprises the reinforcement member, and optionally the reinforcement member is integrally formed with the circuit support.

11. The face mask of any preceding claim, wherein:in the first geometry the upper mask region and lower mask region are folded relative to each other to achieve a first predetermined angular separation therebetween at the mask nose region; and,in the second geometry the upper mask region and lower mask region are folded relative to each other to achieve a second predetermined angular separation therebetween at the mask nose and, optionally, wherein the one or more different parts of the body are selected from: the cranium, torso, back, neck, shoulder, knee, and elbow.15 122512. The face mask of claim 11, wherein the first geometry or second geometry can be variably adjusted to fit different user body sizes.

13. The face mask of any preceding claim, further comprising a second retaining point, the first retaining point being located proximally to the slit and the second retaining point being located distally to the slit.

14. The face mask of any preceding claim, further comprising at least one spacer pad on the inner face of the mask.

15. The face mask of claim 14, wherein the spacer pads are removably attachable to the mask.

16. The face mask of claim 14 or 15, wherein the at least one spacer pad comprises a pair of pads around at least a portion of the periphery of each opening.

17. The face mask of any preceding claim, wherein the mask further comprises a lattice, the lattice comprising a plurality of walls defining a plurality of cells, wherein at least some of the cells each encompass a respective light emitter of the plurality of light emitters.

18. The face mask of any preceding claim, further comprising: a transparent layer covering the light emitters; and, a plurality of lenses, each lens being integrally formed into the transparent layer and aligned with a respective light emitter of at least some of the plurality of light emitters.

19. The face mask of claim 18, wherein each lens comprises a dispersing lens.

20. The face mask of claim 21, wherein the transparent layer comprises:an emitter-facing side facing the plurality of light emitters; and, an opposing face opposite the emitter-facing side, and wherein each lens comprises a meniscus lens defined by a concave segment on the emitter-facing side and a convex segment on the opposing side, the convex segment having a larger radius than the concave segment.

21. The face mask of any preceding claim, further comprising a reflective layer positioned behind the light emitters away from the inner face of the mask, the reflective layer being configured to reflect emitted light towards the skin of the user in use.

22. The face mask of claim 21, wherein the reflective layer comprises a specular reflector and, optionally, wherein the reflector comprises a metallic reflector coating a non-electrically conductive core.

23. A kit of parts, comprising:the face mask of any preceding claim; and, a power source for the face mask.

25. The kit of claim 23, further comprising a user input device for controlling an emission program of at least some of the plurality of light emitters.15 1225

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