Preventing liquid ingress in a device

In an embodiment, a method of manufacturing (100) is described. The method comprises providing (102) a first layer defining a first inner surface (203a) and a first outer surface (203b), a second layer defining a second inner surface (205a) and a second outer surface (205b), and an electrical component (206) positioned on the first inner surface or the second inner surface. The method further comprises attaching (104) the first and second layers together to create a device (200) comprising the first and second layers, wherein the first outer surface and the second outer surface define an external surface of the device. The device further comprises a sealed portion (208) defined by liquid-tight attachment between the first and second inner surfaces. In use of the device, the sealed portion prevents liquid ingress into the device between the first and second layers towards the electrical component.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2021/058389 filed Mar. 31, 2021, which claims the benefit of European Patent Application Number 20167739.0 filed Apr. 2, 2020. These applications are hereby incorporated by reference herein.

FIELD OF THE INVENTION

The invention relates to a device and a method of manufacturing such a device in such a way to prevent liquid ingress into the device, for example, when the device comes into contact with liquid.

BACKGROUND OF THE INVENTION

Certain electronic devices may be constructed in multiple manufacturing stages. For example, in complex supply chains, various components used to construct such electronic devices may be manufactured at different sites by different processes. At the final stage of manufacture, the various components may be integrated together to form the end device. Since the various components may be manufactured at different sites and/or using different processes, the end device may not meet a certain specification in terms of the properties of the device such as dimensions, flexibility, robustness and liquid-tightness while ensuring quality and/or cost effectiveness of the end device.

Printed electronics may provide certain possibilities in terms of integration, miniaturization and/or quality of an end device such as device incorporating a flexible printed circuit board assembly (PCBA). However, where other components such as certain optoelectronic components, light rings, sensors and actuator setups are combined with such a PCBA, the manufacturing process may yield an end device which does not meet a specification or is somewhat limited in terms of a certain property such as dimensions, flexibility, robustness and liquid-tightness. For example, the end device may be bulky, difficult to form into a specified shape, lack robustness needed for a certain application such as in a consumer device and/or have insufficient liquid-tightness to meet a certain specification.

US 2017/005077 A1 describes an electronic device having control circuitry coupled to input-output devices such as a display. A flexible input-output device may be formed from an elastomeric substrate layer. The substrate layer may have signal paths to which components are mounted. Openings may be formed in the elastomeric substrate layer between the signal paths to create a stretchable mesh-shaped substrate.

US 2019/021168 A1 describes a method for manufacturing a multilayer structure for an electronic device. The method includes obtaining a flexible substrate film; printing a number of conductor traces on the flexible substrate film; and providing a number of electronic components on a first surface area of the flexible substrate film. The flexible substrate film further includes a second surface area adjacent to the first surface area. The method further includes molding first thermoplastic material on the number of electronic components and the related first surface area of the flexible substrate film accommodating the components; and molding second thermoplastic material on the adjacent second surface area and on at least part of the first surface area.

U.S. Ser. No. 10/288,800 B1 describes an integrated multilayer structure including a substrate film having a first side and an opposing second side; electronics including at least one light source, provided upon the first side and a number of electrical conductors, at least electrically coupled to the at least one light source.

US 2015377460 A1 describes modular lighting systems that comprise lighting strips physically and electrically connectable with one another by way of flexible connectors.

EP 2484956 A1 describes a flexible lighting element comprising a lighting strip of light sources, covered by an external covering in extrudable silicone elastomer material crosslinkable without heat where said lighting strip is placed between said external covering and a support in heat-conductive material whereon said strip rests.

SUMMARY OF THE INVENTION

Aspects or embodiments described herein relate to improving the manufacture of a device such as an electronic device. Aspects or embodiments described herein may obviate one or more problems associated with manufacturing a device to meet a certain specification.

According to a first aspect, a method is described. The method comprises providing a first layer defining a first inner surface and a first outer surface. The method further comprises providing a second layer defining a second inner surface and a second outer surface. The method further comprises providing an electrical component positioned on the first inner surface or the second inner surface. The method further comprises providing an electrical connection for the electrical component. The electrical connection is printed on the first layer or the second layer. The method further comprises attaching the first and second layers together to create a device comprising the first and second layers with the electrical component and the electrical connection positioned between the first and second layers, so that the electrical component and electrical connection are in contact with both the first inner surface and the second inner surface. The first outer surface and the second outer surface define an external surface of the device. The device further comprises a sealed portion defined by liquid-tight attachment between the first and second inner surfaces around the electrical connection. In use of the device, the sealed portion prevents liquid ingress into the device along the electrical connection between the first and second layers towards the electrical component. The electrical connection is configured to allow electrical communication with the electrical component via the sealed portion. An edge of the first layer is offset from an edge of and the second layers are configured-such that a portion of the electrical connection printed on the first layer or the second layer is exposed for connecting to an electrical power supply.

Some embodiments relating to the first or second aspects are described below. In some embodiments, the electrical connection extends along a surface of the first inner surface or second inner surface and is exposed at an edge of one of the first and second layers to allow electrical communication with the electrical component.

In some embodiments, the electrical component comprises an optoelectronic component for generating and/or detecting an optical signal. The method may further comprise providing an optical element for manipulating the optical signal. The optical element may be provided between the first and second layers before attaching the first and second layers together. The sealed portion may be configured to prevent liquid ingress between the first and second layers towards the optical element.

In some embodiments, the method comprises providing adhesive on at least one of the first and second layers for at least one of: attaching the first and second layers together; and/or adhering the electrical component to at least one of the first and second layers.

In some embodiments, at least one of the first and second layers comprise a shape-adaptable portion. The method may comprise applying a force to the device to cause the device to adopt a specified shape.

In some embodiments, the method comprises distributing the electrical component and at least one other component between the first and second layers in such a way that a substantially continuous flexibility is provided along the device created by attaching the first and second layers together.

In some embodiments, at least one of the first and second layers comprises a surface of an appliance. The method may comprise attaching the other of the first and second layers to the surface of the appliance to create the device.

According to a second aspect, a device is provided. The device comprises a first layer defining a first inner surface and a first outer surface. The device further comprises a second layer defining a second inner surface and a second outer surface. The first outer surface and the second outer surface define an external surface of the device. The device further comprises an electrical component positioned between the first and second layers. The device further comprises an electrical connection, for the electrical component, positioned between the first and second layers. The electrical connection is printed on the first layer or the second layer. The electrical component and the electrical connection are in contact with both the first inner surface and the second inner surface. The first and second layers are attached together to form a sealed portion defined by liquid-tight attachment between the first and second inner surfaces around the electrical connection. In use of the device, the sealed portion prevents liquid ingress into the device along the electrical connection between the first and second layers towards the electrical component. The electrical connection is configured to allow electrical communication with the electrical component via the sealed portion. An edge of the first layer is offset from an edge of the second layers such that a portion of the electrical connection printed on the first layer or the second layer is exposed for connecting to an electrical power supply.

Some embodiments relating to the second aspects are described below.

In some embodiments, the electrical component comprises an optoelectronic component for generating and/or detecting an optical signal.

In some embodiments, the device comprises an optical element for manipulating the optical signal.

In some embodiments, at least one of the first and second layers comprises a transparent portion for allowing transmission of the optical signal through at least one of the first and second layers.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG.1shows a method100, which may be a method of manufacturing a device such as described below. The method100comprises, at block102, providing a first layer, a second layer and an (e.g., at least one) electrical component between the first and second layers. The first layer defines a first inner surface and a first outer surface. The second layer defines a second inner surface and a second outer surface. The electrical component is positioned on the first inner surface or the second inner surface.

The manner by which the first layer, second layer and electrical component are provided may depend on the situation or purpose of the device and/or the nature of the first layer, second layer and/or electrical component.

For example, the first layer may be provided (e.g., at a particular location) and then the second layer may be provided (e.g., at or near that particular location) such that the electrical component is located between the first and second layers before proceeding to the next block of the method100.

The electrical component may be provided at an appropriate time between the first and second layers by positioning the electrical component at an appropriate location on, adjacent to or within (e.g., embedded or otherwise incorporated within) the first layer or second layer.

In an example, the electrical component may be provided in situ where the first layer and second layer are provided (e.g., as part of block102) before the method100proceeds to the next block of the method100. For example, the first layer may be provided before providing the electrical component, which may be positioned on the first layer (i.e., the first inner surface) before providing the second layer.

In another example, the first layer or second layer may already include the electrical component. For example, the electrical component may be attached to, integrated within or otherwise provided as part of one of the first and second layers (e.g., if this layer is manufactured at a different site).

The term “layer” is not intended to be limiting to any particular dimension or cross-sectional aspect ratio for that layer. For example, both of the first and second layers may be relatively thin such that their combined thickness is of order a millimeter or below a millimeter. In another example, one of the first and second layers may be relatively thin (e.g., with a thickness of order of a hundred microns, several hundred microns, or below a millimeter) while the other of the first and second layers may be relatively thicker (e.g., with a thickness of greater than a millimeter). In another example, both of the first and second layers may be relatively thick such that their combined thickness is greater than a millimeter such as several millimeters.

Further, the term “layer” is not intended to be limiting to a single entity by itself. For example, a layer may refer to part of (e.g., a surface of) a larger entity such as a consumer appliance (e.g., a shaver unit, toothbrush unit or the like).

The method100further comprises, at block104, attaching the first and second layers together to create a device comprising the first and second layers. The first outer surface and second outer surface define an external surface of the device. The device further comprises a sealed portion defined by liquid-tight attachment between the first and second inner surfaces, to prevent liquid ingress into the device between the first and second layers towards the electrical component.

Since the electrical component is between the first and second layers, by attaching the first and second layers together, the electrical component (and any other components) may be at least partially or fully sealed within the device. The sealed portion of the device may be such that liquid such as water is prevented from penetrating between the first and second layers if the device contacts or is immersed in the liquid. The electrical component (and any other components) between the first and second layers may be protected from the liquid so that the electrical component (and any other components) may continue to function as intended even if the device has come into contact with or is in contact with liquid. The method100may be used to create a device which is relatively compact, for example, due to the relatively straightforward and/or efficient manufacturing process for creating the device (i.e., a single step of attaching the first and second layers together to form the sealed portion). The device created by the method100may be intrinsically fluid-tight, robust and/or relatively compact due to the relatively straightforward and/or efficient manufacturing process. For example, as compared to an example manufacturing process which initially creates a device and then attempts to seal the device by some separate process, the present method100simultaneously creates (e.g., assembles) the device and seals the electrical component within the device at the same time.

Attaching can be achieved by, for example: providing adhesive on one or both of the first and second layers and then placing the layers together to allow the layers to become attached; bonding the layers together by applying heat to one or both of the layers; causing diffusion of material in one of the layers to another of the layers to thereby attach the first and second layers together; or otherwise causing attachment of the first and second layers together.

Accordingly, the method100may be used to manufacture the device in a single-process set up (e.g., with multiple sheet-to-sheet or roll-to-roll production steps at one single production line) to create an intrinsic liquid-tight device such as may be applied in water-robust handheld appliances. In some cases, the device may be formed as a thin film mechatronic laminate. Water-robust handheld appliances such as shaver units may have limited electrical power, occupy a small volume and/or have strong curvatures in certain components used in the assembly of the appliance (which may mean that the device needs to be bent to fit within the assembly). Since such handheld appliances may, in use, be exposed to water, the components used in the device may need to be intrinsically water-tight to meet specification. As mentioned above, the method100may facilitate the manufacture of a device that meets a certain specification, for example, as specified for water-robust handheld appliances.

As will be discussed in more detail below, other components in addition to the electrical component may be included in the device. For example, optoelectronic/optical components and/or mechanical components may be provided between the first and second layers and sealed therebetween. Accordingly, the end device may meet a certain specification in terms of flexibility, robustness, thickness, liquid-tightness and the like while the end device contains the electrical component(s), mechanical component(s) and/or optical component(s) for the specified application. Further, the end device may be provided in a specified shape, for example, to be applied in e.g. a shaver unit.

FIG.2shows a device200manufactured in accordance with the method100ofFIG.1. The device200comprises a first layer202comprising a first inner surface203aand a first outer surface203b, a second layer204defining a second inner surface205aand a second outer surface205band an electrical component206between the first and second layers202,204.FIG.2includes an expanded view of part of the device200where the separation between the first and second layers202,204is exaggerated to more clearly show the respective surfaces. In this embodiment, the first and second layers202,204are in contact with each other, or at least in close proximity to each other. The first outer surface203band the second outer surface205bdefine an external surface of the device200. The first and second layers202,204are attached together (i.e., as part of a method of manufacture such as described by method100). Prior to attachment, the electrical component206is positioned on, or otherwise embedded in or attached to, the first inner surface203aor the second inner surface205a(i.e., either positioned on the first inner surface203aor the second inner surface205abefore the first and second layers202,204are attached together). The first and second layers202,204are attached together to form a sealed portion208defined by liquid-tight attachment between the first and second inner surfaces203a,205a. In use of the device200, the sealed portion208prevents liquid ingress into the device200between the first and second layers202,204towards the electrical component206. In this embodiment, the first and second layers202,204completely surround the electrical component206such that the sealed portion208extends all the way around the electrical component206. Liquid ingress between the first and second layers202,204towards the electrical component206may thus be prevented. Further details of embodiments of the device200are described in more detail below.

FIGS.3ato3dshow various views of a device300being manufactured in accordance with certain methods described herein (such as method100or method600described below). The device300is similar to device200ofFIG.2but shows additional details of the device200. Reference signs for features of the device300which correspond to similar features of the device200are incremented by 100 as compared toFIG.2.

InFIGS.3ato3b, the device300is depicted in its pre-manufactured form (i.e., at block102of the method100) where the first layer302, second layer304and the electrical component306have been provided. InFIGS.3cto3d, the device is depicted in its manufactured form (i.e., at block104of the method100) where the first and second layers302,304have been attached together.FIGS.3band3dare side views of the device300as indicated by the direction A-A inFIGS.3aand3c.

Additionally, an electrical connection310is provided between the first and second layers302,304. The electrical connection310is configured to allow electrical communication with the electrical component306via the sealed portion308as shown inFIG.3c. In this embodiment, the electrical connection310comprises two electrical connections310, as depicted by the side view ofFIGS.3band3d, which are provided on the inner surface303aof the first layer302. Although two electrical connections310are shown, a different number of electrical connections310may be provided, depending on the circuitry needed for allowing electrical communication with the specified type of electrical component306.

In an embodiment, the electrical connections310comprise printed circuitry (e.g., a metal such as silver printed on the surface of the first layer302). In an example, as part of certain methods described herein, the first layer302may be provided in situ and then the electrical connections310may be printed on the first layer302before attaching the second layer304to the first layer302. In another example, as part of certain methods described herein, the electrical connections310may be printed on the first layer302in another manufacturing site and then the first layer302(including the printed electrical connections310) and the second layer304may be provided and then attached together.

As can be seen fromFIGS.3aand3c, the first and second layers302,304are configured such that at least a portion of the electrical connection310is exposed between the first and second layers to allow electrical communication with the electrical component306. In this embodiment, the first and second layers302,304are offset such that when the first and second layers302,304are attached together, a portion of the electrical connections310is exposed while still ensuring that the sealed portion308(e.g., defined by contact between the first and second layers302,304around the electrical connections310) prevents liquid ingress between the first and second layers302,304and/or along the electrical connections310between the first and second layers302,304. In this embodiment, the electrical connections310extend along the first inner surface303a(i.e., where these layers302,304are facing each other) and the electrical connections310are exposed at an edge of the second layer304to allow electrical communication with the electrical component306.

As can be seen fromFIGS.3band3d, the first and second layers302,304completely surround the electrical component306between the first and second layers302,304. Further, the first and second layers302,304surround the electrical connections310between the first and second layers302,304while the offset between the edges of the first and second layers302,304ensures that at least a portion of the electrical connections310is exposed to allow electrical communication with the electrical component306via the sealed portion308.

The exposed electrical connection310may need to be sealed in a liquid-tight body (e.g., by an over-molding process or a heat lamination process) via a separate process to make the electrical connection to a controller (not shown, which may be the part of the appliance for supplying electrical power to the electrical component306) external to the device300. Nonetheless, even if this separate process does not adequately seal the exposed electrical connection310, the attachment of the first and second layers302,304may be sufficient to prevent ingress of liquid towards the electrical component306between the first and second layers302,304.

The method illustrated byFIGS.3a-3dand other methods described herein may be used to create a device with a relatively compact volume and/or thickness as compared to devices created by certain other manufacturing processes. Such a device may be relatively compact for use in assembling an appliance. For example, the device may be configured as a light ring or functional device or laminate in such an appliance. A light ring may produce light to provide information such as battery charge level, power on/off status and/or to provide illumination for a user of the appliance. In some examples, a functional device or laminate may perform some function such as detecting a user input (e.g., if the electrical component comprises a sensor such as a touch sensor), which may be used to control the appliance and/or sense some other input from the environment such as temperature, humidity, or the like. In some examples, the functional device or laminate may comprise a communication device (e.g., configured for Bluetooth, WiFi, Near Field Communication (NFC), optical, cellular (4G, 5G, etc) communication, or the like).

FIG.4shows another device400manufactured in accordance with certain methods described herein (such as method100or method700described below). The device400is similar to device300ofFIG.3but shows certain other features. Reference signs for features of the device400which correspond to similar features of the device300are incremented by 100 as compared toFIG.3.

In this embodiment, the device400is manufactured in a similar way to that depicted byFIGS.3ato3dwhereby the first and second layers402,404are initially provided in a planar form and then attached together to form the device400. At least one of the first and second layers402,404comprise a shape-adaptable portion. The shape-adaptable portion may be: flexible, stretchable, compressible and/or elastic. In other similar words, the shape-adaptable portion may have any appropriate mechanical property for allowing the portion (and/or the layer) to change its shape or form. For example, the shape-adaptable portion of the first and/or second layers402,404may comprise a material such as a flexible polymer and/or be otherwise constructed such that the shape-adaptable portion is less stiff (or, in other words, more flexible or stretchable) than another portion of the device400. In this embodiment, both of the first and second layers402,404are made of polymer and are flexible throughout. The polymer may be resistant to liquid (e.g., water-tight) such that liquid may be prevented from penetrating through the layer402,404.

A force may be applied to the device400to cause the device400to adopt a specified shape, for example, an arcuate shape as shown byFIG.4or a ring-like shape (not shown). The device400may retain its intrinsically fluid-tight and robust structure even though the device400has been flexed as shown. The ability for the device400to adopt a specified shape may allow the device400to be readily incorporated with an appliance in a specified manner. For example, an appliance such as a shaver unit (not shown) may have various contours and the device400may be flexed to adopt a specified shape which matches the contours of the appliance when incorporated (e.g., embedded into a slot in) the appliance.

The device400comprises an electrical component406and at least one other component406. The other components may or may not be electrical components and there may be different numbers of components (e.g., two or more). In an example, at least one other component406may comprise an optical element such as a waveguide, lens, prism, reflector, diffuser, optically transparent portion, optically opaque portion, or the like. In another example, at least one other component406may comprise a structural component for providing certain mechanical properties such as stiffness, flexibility, or the like at the location where the component is provided between the first and second layers402,404.

In this embodiment, the electrical component406and the other components406are distributed between the first and second layers in such a way that a substantially continuous flexibility (or in other words, a substantially continuous stiffness) is provided along (e.g., along a length or width of) the device400created by attaching the first and second layers402,404together. As can be seen fromFIG.4, the components406are evenly spaced apart between the first and second layers402,404and are of a similar size such that the device400can adopt a shape with a constant bending radius as depicted byFIG.4. This even spacing of the components406and/or ensuring a continuous flexibility is provided along the device400may reduce stress peaks at certain locations of the device400when the device is flexed to form a specified shape (which may otherwise cause delamination of the layers402,404at those locations) and may also minimize the volume needed for assembling the device400.

Any components which are rigid may cause local stiffness within a device400which otherwise comprises a stretchable and/or flexible layer. Such local stiffness may cause difficulties in allowing the device400to adopt certain shapes. By appropriately distributing the components406within the device400, the flexibility along the device400(e.g., between the components) may be substantially the same along the device400. In other words, the flexibility may be substantially continuous along the length or width of the device400apart from where any rigid components interfere with this flexibility and introduce local stiffness. Further, the distribution of the components may be such as to minimize areas of high stress concentrations between the layers when bending the device400. For example, distributing the components406apart from each other may minimize stress at the location of the components406(in contrast to a scenario where the components are adjacent to each other). Such even distribution of the components406may reduce the likelihood of delamination (e.g., instantly upon bending or over time) which may affect the quality of the seal provided by the two layers402,404.

As depicted byFIG.4, the device400may comprise evenly distributed components406throughout the device400. The device400may be evenly filled with components406to reduce the possibility of gaps or air pockets between the components causing certain problems with the device400. For example, delamination of the layers402,404may be caused by expanding air pockets in the device400(e.g., under a varying (thermal) load case). Reducing the number and/or size of such spaces or air pockets by evenly distributing the components406within the device400may reduce the risk of the integrity of the device400being compromised. Where an over-molding process such as injection molding is applied to the device400(e.g., to integrate the device400with an appliance), the molding process may apply pressure and/or heat which may compress the device400in regions where such spaces or air pockets exist in the device400. Again, minimizing the number and/or size of such spaces or air pockets may avoid local compression of the device400, which may otherwise adversely affect the expected functionality of the device400. In some examples, gaps or air pockets may be minimized or eliminated by using a vacuum-based lamination technique. In this case, at least one of the first and second layers402,404may conform to the shape of the other layer and/or any components406between the layers402,404.

Different components406may be of certain sizes and/or have certain mechanical properties which may affect how the device400responds when flexed in certain ways. Accordingly, additional components (not shown) may be provided between the first and second layers402,404to provide certain mechanical properties at certain locations between the first and second layers402,404in order to provide a specified flexibility, stretchiness or stiffness along the device400. In some cases, a non-continuous flexibility or stiffness may be provided along the device400due to the mechanical properties of the components406between the first and second layers402,404and/or due to the mechanical properties of the at least one of the first and second layers402,404.

As can be seen inFIG.4, certain methods described herein may be used to create a device400with relatively increased geometrical flexibility as compared to devices created by certain other manufacturing processes (e.g., involving multiple production steps at different sites). For example, the flexibility of the device400ofFIG.4may allow a three-dimensional light ring or other functional device to be created by initially manufacturing the device400in a substantially two-dimensional geometry and then shaping the device400to form a three-dimensional geometry. This device400may then be applied to or otherwise combined with an appliance (not shown) such as a handheld appliance where a specified three-dimensional shape is specified in order to appropriately apply or otherwise combine the device400with the appliance.

Further, certain methods described herein may provide for efficient production of a three-dimensional (3D) device. As highlighted byFIGS.3to4, the device may be manufactured with a two-dimensional (2D) geometry and then shaped to form a specified 3D geometry. For example, a 2D manufacturing process such as sheet-to-sheet or roll-to-roll assembly line may be used to create the 2D device and then the 2D device may be adapted into a 3D assembly part-by-part directly in an appliance, which may avoid needing to use more complex three-dimensional production processes such as complex 3D lamination or 3D sealing by assembly.

AlthoughFIG.4depicts the device400as being constructed of two flexible layers402,404, there may be other device configurations where at least one of the layers is not flexible and/or the device400is constructed in a different manner with certain features providing flexibility where the layers402,404do not provide such flexibility.

For example, at least one of the layers402,404may be stretchable or compressible (e.g., at least in a direction along a length or width of the layer). At least one of layers may comprise a foil which may include ink (e.g., for providing patterning in or on the layer). Such a layer may be stretchable so that the ink does not crack or otherwise deform when stretched or compressed. In an example, if polyethylene terephthalate (PET) and/or polyethylene naphthalate (PEN) is used for one or both of the layers402,404, the combination may be relatively rigid. However, a core (e.g., comprising the components406) between the two layers402,404may be flexible such that the overall device400may be relatively flexible. There may be scenarios where bending of such a device400may cause delamination and/or breakage of certain parts. A layer of the device400may be relatively non-stretchable or incompressible along its length or width (yet is still flexible) such that, during bending, the layer has the smallest bending radius (and no stretching) of the various layers of the device. In some cases, a layer that is relatively non-stretchable or incompressible may be used for supporting any rigid components (e.g., surface-mount devices (SMD) such as certain electronic components) to reduce the risk of damaging or dislodging the component due to minimized stretching or compressing of that layer during bending of the device400.

FIG.5shows an exploded view of another device500manufactured in accordance with certain methods described herein (such as method100or method600described below). The device500is similar to device400ofFIG.4but shows certain other features. Reference signs for features of the device500which correspond to similar features of the device400are incremented by 100 as compared toFIG.4.

As before, the device500comprises a first layer502and a second layer504. The structure of the first and second layers502,504is described in more detail below. Various components are provided between the first and second layers502,504. In this embodiment, these components are provided on the first layer502and then the second layer504is attached to the first layer502. The point of attachment of the first and second layers502,504is not shown for brevity inFIG.5since this is already shown in the previous figures. Instead,FIG.5is an expanded view of the structure of the components and the first and second layers502,504. The first and second layers502,504may be constructed in situ where the device500is manufactured or at least one of the first and second layers502,504may be manufactured elsewhere and then provided in situ where the device500is manufactured. The process for manufacturing the device500from bottom layer to the top layer (i.e., the first layer502to the second layer504) is now described.

The first layer502comprises a polymer layer which, in this embodiment, comprises thermoplastic polyurethane (TPU). TPU may be optically transparent to certain wavelengths or may opaque to certain wavelengths (e.g., TPU white or black). In this case, the first layer502comprises TPU white but in other cases could comprise a different color such as black (e.g., to avoid light penetration or leakage). In some other embodiments, the first layer502may comprise a relatively non-stretching material such as PEN, PET, polyimide (PI), or the like. Certain SMD components may be better supported on the first layer502if the first layer502is relatively non-stretching since, in some scenarios, TPU may be too stretchable for some SMD-type components. The first layer502of this embodiment may be used to support components and electrical conductors such as tracks and may, depending on its color, be used for blocking light from penetrating therethrough.

Circuitry512(e.g., silver and/or another appropriate conductive material) is then printed on the first layer502. The circuitry comprises the electrical connection referred to inFIGS.2to3and provides electrical communication for any electrical components in the device500. In some cases, electrical components (e.g., resistors, inductors, capacitors, microprocessors, or the like) other than electrical connections may be provided and/or printed as part of the circuitry512.

A conductive adhesive such as isotropic conductive adhesive (ICA)514is deposited at certain locations on the circuitry512. This provides part of the electrical connection to certain electrical components of the device500. In this embodiment, a polymer portion516(e.g., TPU white) is provided (e.g., by printing, molding or otherwise depositing the polymer portion516) on the circuitry516. The polymer portion516may provide certain functionality such as providing certain mechanical properties (e.g., support for other components and/or certain stiffness or flexibility) at that location of the device500. In this embodiment, the polymer portion516is optically opaque (e.g., to prevent light from escaping an adjacent component of the device500described below).

In this embodiment, the first layer502(including the various components described above) is approximately 0.3 mm thick although other thicknesses are possible (such as less than or more than 0.3 mm). For ease of reference, the combination of the first layer502, the circuitry512, ICAs514and polymer portion516shall simply be referred to as the first layer502below.

Various components are provided on the first layer502. First and second electrical components506a,bare positioned on the ICAs514. In this embodiment, the electrical components506a,beach comprise an optoelectronic component in the form of a light emitting diode (LED). The LEDs produce an optical signal which is emitted from the device500as will be described in more detail below.

The first electrical component506a(LED) emits an optical signal518ain a vertical direction (i.e., towards the second layer504).

The second electrical component506b(LED) emits an optical signal518bin a horizontal direction (i.e., in a plane parallel to the first and second layers502,504). An optical element520is provided for manipulating the optical signal518b. The optical element520is located adjacent to the second electrical component506band is optically coupled to the second electrical component506b. In this embodiment, the optical element520comprises an optical waveguide that directs the optical signal emitted by the second electrical component506along the optical waveguide. In use of the device500, the optical signal518bpropagates along the optical waveguide. The optical element520may be configured such that the optical signal518bchanges direction and propagates towards the second layer504. For example, the optical element520may comprise at least one reflective structure such as for changing the direction of the optical signal518b.

An additional polymer portion522(e.g., the portion522may comprise a single TPU white or TPU dense white portion, or may comprise multiple layers such as a white layer combined with a (e.g., printed) black layer for blocking light from neighboring optical elements520) is provided between the first electrical component506aand the optical element520. As with the polymer portion516, the additional polymer portion522may provide certain functionality such as providing certain mechanical properties (e.g., support for other components and/or certain stiffness or flexibility) at that location of the device500. In this embodiment, the additional polymer portion522is optically opaque (e.g., to prevent light from escaping from the optical element520and/or reflecting the optical signal518bwithin the optical element520). The additional polymer portion522may be provided by, for example, being formed (e.g., solidified) and positioned at its location, layered, or by being molded in situ, or the like. As mentioned above, a black layer may be provided as part of the additional polymer portion522(e.g., extending all the way across the top of the core/layer shown inFIG.5comprising the electrical components506). This black layer may comprise openings such that light from the first and second electrical components506a,506bcan exit this core/layer and then escape from the second layer504, as described in more detail below.

In some embodiments, the various components described above including the electrical components506a,b, optical element520and the additional polymer portion522may be provided as a layer in itself (e.g., with these various components integrated within the layer). In this embodiment, the thickness of these various components is approximately 0.7 mm although other thicknesses are possible (such as less than or more than 0.7 mm).

After the various components described above have been provided, additional components may be provided. In this embodiment, an additional optical element in the form of a diffuser layer524(e.g., an optical diffuser) is provided on top of the components described above. The diffuser layer524may diffuse the optical signals518a,bto provide a more uniform distribution of the illumination compared with the direct illumination provided by an LED by itself. First and second additional polymer layers526,528(e.g., comprising TPU white, TPU black, optically transparent TPU and/or ink) are provided on the diffuser layer526. In this embodiment, the first additional polymer layer526comprises TPU white portions526aand transparent portions526b. The second additional polymer layer528comprises TPU black portions528aand transparent portions528b. The transparent portions526b,528bare aligned relative to the first electrical component506aand optical element520such that the optical signals518a,bmay pass through the transparent portions526b,528band out of the device500. Although certain components are described as having a certain color (e.g., black or white), other colors may be used where appropriate (e.g. for aesthetic considerations and/or for functional considerations such as absorbing or reflecting light).

In this embodiment, the diffuser layer526and first and second additional polymer layers526,528may be regarded as the ‘second layer504’. However, in some embodiments, the second additional polymer layer528may be regarded as the ‘second layer504’ and in other embodiments, the combination of the first and second additional polymer layers526,528may be regarded as the ‘second layer504’. In this embodiment, the second layer504is approximately 0.1 mm thick although other thicknesses are possible (such as less than or more than 0.1 mm).

Accordingly, any of the layers502,504may comprise at least one layer. Thus, the device500may be regarded as comprising at least two layers. The overall thickness of the device500may be of order 1 mm although other thickness are possible (such as less than or more than 1 mm).

It is mentioned above that certain layers comprise polymer and certain components (or layers comprising such components) may comprise various materials such as metal, plastic, etc. In some cases, a functional printed layer of the device500may be dominantly metal, polymer or ceramic in a dry state.

In some embodiments, the device500may be intrinsically liquid-tight (e.g., water-tight) due to the first and second layers502,504being attached together (not shown inFIG.5but shown inFIGS.2to3) such that the device500can potentially be submerged in water (or any other electrically conducting liquid) without causing malfunctioning of the device500(e.g., due to an electrical short circuit or optical performance loss). Providing the circuitry512of the device500is sealed by attaching the first and second layers502,504together (e.g., seeFIGS.3to4), water ingress may be prevented. Such intrinsic liquid-tightness may useful for an appliance such as a shaver unit which, in use, may be rinsed under running water.

Various components may be sealed within the device500during the manufacturing process in accordance with certain methods described herein. For example, a light guide, a sensor and/or (e.g., solid-state) actuator (e.g., touch sensor) may be provided to perform certain functions in an appliance such as a shaver unit like touch controls and user feedback control (e.g., by resonance at remote positions from the surface/main board of the appliance).

The relatively straightforward manufacturing process may facilitate accurate alignment of components such as LEDs and optical elements in the device500by placing them in the device500in one production setup, which may ensure appropriate alignment of such components and therefore may reduce or avoid losses in terms of electrical-to-optical signal conversion efficiency within the device500.

As noted above, various types of optical element520may be integrated within device500during manufacture thereof. Certain optical elements520such as prisms (which may be used to homogenize the optical signal518boutput by the device500) may be relatively bulky and/or difficult to integrate using certain manufacturing processes. The same may apply to any of the other types of optical elements described herein such as a waveguides, lenses, and reflectors. However, certain methods described herein may facilitate the integration of such optical elements520and other components in the device500.

Although not shown inFIG.5, a refractive index matching adhesive may be provided in any spaces between the components through which the optical signal518a,bpropagates. Such index-matching adhesive may avoid or reduce optical losses and/or improve homogeneity of the optical signal output by the device500.

Certain components of the device500may create certain illuminated compartments within the device500which are surrounded by components for preventing any unintended escape of the optical signal518a,b(e.g., due to use of opaque components within the device500). Such opaque components (e.g., the additional polymer portion522) may be used avoid cross talk between the different optical signals518a,b. These opaque components may be relatively straightforward to install in the device500while also being relatively effective in terms of avoiding optical losses.

Devices described herein may be integrated in an appliance as a 2D-shaped device or as a 3D-shaped device. In some cases, it may be possible to thermoform, back mold and/or over mold such devices with a polymer (e.g., adhesive and/or sealant) to create a solid integrated structure (e.g., within an enclosure of the appliance) comprising the appliance and the device integrated with the appliance. In an example, a plate (e.g., ‘layer’) of polycarbonate or polymethyl methacrylate (PMMA) may be thermoformed in the presence of the device500. In a further example, the thermoformed device combination may be molded to create the solid integrated structure mentioned above.

FIG.6depicts another device600with a similar form to the device300as shown byFIG.3c. Similar to the device300, the device600comprises first and second layers602,604, an electrical component606, a sealed portion608and electrical connection610. Additionally, the device600comprises an isolating portion630provided on part of the electrical connection610and extending partway into the sealed portion608of the device600between the first and second layers602,604. The isolating portion630also extends partway along the electrical connection610(where the second layer604is not provided) such that part of the electrical connection610is exposed as described above. In other similar words, the first and second layers602,604are still configured such that at least a portion of the electrical connection610is exposed between the first and second layers602,604to allow electrical communication with the electrical component606. However, the isolating portion630may provide additional protection from liquid ingress between the first and second layers602,604since the electrical connection610itself is protected (e.g., isolated) at the edge of the second layer604offset from the first layer602.

The isolating portion630may comprise a polymer (e.g., bulk or printed) and/or another material to isolate the electrical connection610underneath from liquid contact. The isolating portion630may be relatively thin compared with the second layer604such that the combination of the first layer602, electrical connection610and the isolating portion630may be relatively thinner than the combined thickness of the first and second layers602,604(as shown byFIG.6). This relatively thinner part of the device600may be referred to as a connecting ‘tail’ since this part may be installed at, for example, a power supply of an appliance.

FIG.7refers to a method700of manufacturing a device in accordance with certain embodiments described above. The method700may comprise at least one of the blocks102,104of the method100ofFIG.1and reference is also made to these blocks of the method100for ease. Certain blocks may be omitted from the method700, where appropriate. Further, the sequence of the blocks may be changed in some cases.

In some embodiments, the method700comprises, at block702, providing an electrical connection on one of the first and second layers before attaching the first and second layers together. The electrical connection may be configured to allow electrical communication with the electrical component via the sealed portion.

In some embodiments, the method700comprises, at block704, positioning the electrical component on one of the first and second layers before attaching the first and second layers together (e.g., at block104).

In some embodiments, the electrical component comprises an optoelectronic component for generating and/or detecting an optical signal. In this regard, the method700further comprises, at block706, providing an optical element for manipulating the optical signal. The optical element may be provided between the first and second layers before attaching the first and second layers together. The sealed portion may be configured to prevent liquid ingress between the first and second layers towards the optical element.

In some embodiments, the method700comprises, at block708, providing adhesive on at least one of the first and second layers for at least one of: attaching the first and second layers together; and adhering the electrical component to at least one of the first and second layers.

In some embodiments, at least one of the first and second layers comprises a flexible portion. In this regard, the method700may comprise, at block710, applying a force to the device to cause the device to adopt a specified shape.

In some embodiments, the method700may comprise, as part of block102, distributing the electrical component and at least one other component between the first and second layers in such a way that a substantially continuous stiffness is provided along the device created, at block104, by attaching the first and second layers together.

In some embodiments, at least one of the first and second layers comprises a surface of an appliance. In this regard, the method700may comprise, at block712, attaching the other of the first and second layers to the surface of the appliance to create the device. The device may therefore be simultaneously created and sealed to the surface of the appliance.

One or more features described in one embodiment may be combined with or replace features described in another embodiment. For example, the method100or700ofFIG.1or7may be modified based on features described in relation to the device200,300,400,500,600ofFIGS.2,3,4,5and6, and vice versa. Further, certain features of one of the device200,300,400,500,600may be combined with, replace or otherwise modify certain features of another of the devices200,300,400,500,600.

The present disclosure is described with reference to flow charts and block diagrams of the method, devices and systems according to embodiments of the present disclosure. Although the flow charts described above show a specific order of execution, the order of execution may differ from that which is depicted. Blocks described in relation to one flow chart may be combined with those of another flow chart.

Elements or steps described in relation to one embodiment may be combined with or replaced by elements or steps described in relation to another embodiment. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practising the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. Any reference signs in the claims should not be construed as limiting the scope.