CN115781771A - Shaving unit and electric shaver comprising same - Google Patents

Abstract

The present disclosure relates to a shaving unit and an electric shaver including the shaving unit. A shaving unit and/or an electric shaver has an illumination module for providing an optical heating function at a skin contact surface of the shaving unit. At least one aspect of the invention relates to a packaging arrangement for components of a lighting module by means of a potting material which encapsulates, on an upper side and a lower side, a carrier on which a lighting element is mounted.

Description

Shaving unit and electric shaver comprising same

Technical Field

The present invention relates to a shaving unit for an electric shaver, and an electric shaver including the shaving unit.

Background

The present invention is in the field of shavers, in particular electric shavers, which are designed to perform a shaving action or the like, wherein hairs are cut at a position close to the skin. Generally, an electric shaver comprises a shaving unit in which one or more hair cutting units are arranged, wherein the shaving unit comprises a base member for supporting the one or more hair cutting units. A particularly common design of a shaving unit is to use three hair-cutting units in an equilateral triangular configuration. The electric shaver includes a body in addition to the shaving unit. The body is generally shaped to be held by a user of the shaver and may house various components of the shaver, such as an electric motor.

Each hair cutting unit of the shaving unit comprises a combination of an internal cutting member and an external cutting member, the external cutting member being arranged to cover the internal cutting member, the external cutting member being provided with a series of hair entry openings for allowing hairs to pass through the external cutting member to and encounter the internal cutting member during a shaving action. In a practical design, the external cutting member is generally cup-shaped and has a substantially circular circumference, wherein the hair entry openings may be shaped like elongated slits extending substantially radially with respect to the central axis of the external cutting member in one or more annular areas constituting one or more hair cutting trajectories. Such an external cutting member is particularly suitable for a rotary electric shaver, i.e. an electric shaver comprising at least one hair cutting unit, wherein the internal cutting member is arranged to rotate during operation.

Proper use of an electric shaver comprises placing the shaver in an active state, i.e. a state in which the internal cutting member of at least one hair-cutting element is rotated, and moving the shaving unit over a portion of the skin to be subjected to a shaving action. The external cutting member has a hair cutting track surface for contacting a portion of the skin at the location of one or more hair cutting tracks during a hair cutting action. The hair cutting surface is present in the outer cutting member at a position defining a hair entry opening. In a conventional design, the internal cutting member comprises a blade edge with a hair cutting edge. During a shaving action, hairs entering the hair entry openings are cut between the hair cutting surface and the hair cutting edge and are thus severed at a location close to the skin.

CN 108714917a discloses an electric shaver comprising a shaving unit and a main body. The shaver is equipped with an infrared heating device, a battery and a switch electrically connected to each other. The reason for equipping electric shavers with infrared (or near infrared) heating means, such as known from CN 108714917a, is the fact that exposure of the hair to infrared light helps to soften the hair. In general, exposing hair to infrared light during a shaving action improves the comfort of the user experience. Furthermore, by stimulating the skin and causing the radiant appearance of the skin, infrared light can also stimulate blood circulation and have beneficial effects on the skin.

Not only infrared light but also other light emissions may be used to generate the heating stimulus, including in the visible spectrum.

In conventional electric shavers, all electrically active components are contained in a body having a water-tight housing surrounding all internal components. However, including the lighting module in the shaving head means that the electrically active components are arranged outside the housing of the body. This poses problems for long-term reliability of the shaving head. An improvement over existing designs that could solve this problem would be valuable.

Disclosure of Invention

The invention is defined by the claims.

According to one aspect of the present invention, a shaving unit for an electric shaver is provided. The shaving unit includes: one or more hair cutting elements; a lighting module comprising a lighting module housing containing one or more lighting elements; and a support member supporting the one or more hair cutting units and the lighting module. The lighting module housing has a cavity, wherein the lighting element is arranged in the cavity, and wherein the cavity is covered by an upper wall of the lighting module housing at a skin facing side of the lighting module housing. The upper wall of the illumination module housing is preferably made of a light-transmitting material and comprises a skin-facing light output surface via which the light generated by the illumination element is exposed to the skin during operation of the shaving unit. The light output surface is arranged to contact the skin during operation of the shaving unit.

The lighting module comprises a PCB arranged in the cavity, and wherein the lighting element is mounted to a first main surface of the PCB facing the upper wall of the lighting module housing such that the lighting element is in optical communication with the light output surface during operation of the shaving unit.

The cavity includes a light transmissive potting material covering the first major surface of the PCB encapsulating the lighting element and extending between the first major surface of the PCB and the upper wall of the lighting module housing. The potting material also covers a second major surface of the PCB opposite the first major surface. The potting material thus encapsulates the PCB on all major sides.

The shaving unit may for example form a shaving head for a shaving apparatus, for example adapted to be attached to a shaver body having a motor, as will be described in more detail later.

The lighting module of the shaving unit according to the invention is capable of providing a heating effect to the skin during a shaving process. The heating effect is achieved optically and conductively. Optical heating of the skin is achieved by optical absorption of light by the skin tissue generated by the illumination element and applied to the skin via the light output surface of the illumination module. The conductive heating of the skin is achieved by thermal contact of the skin with a light output surface of the lighting module, which is in heat conducting contact with the lighting element via the potting material and the upper wall of the lighting module housing. Thus, due to the limited electro-optical energy conversion efficiency of the lighting element, conductive heating of the skin is in particular achieved by the heat dissipated by the lighting element. This combined optical and conductive heating of the skin is very effective.

This protects the lighting element from moisture ingress by fully encapsulating the lighting element in a potting material. Furthermore, by having the potting material extend from the light emitting element to the light output surface (which also forms the skin contact surface), the potting material provides an auxiliary function of regulating the heat conduction from the light emitting element to the light output surface in contact with the skin, which improves the efficiency of the skin warming. In particular, there is not only radiative heat transfer from the lighting element to the skin contact surface (as in known devices), but also conductive heat transfer to the skin contact surface. Furthermore, by facilitating conductive heat transfer with the same potting material that provides fluid insulation of the lighting elements, there is structural efficiency achieved by the proposed arrangement.

It is advantageous if the potting material is arranged such that it extends uninterrupted from the first main surface of the PCB to the upper wall of the lighting module housing. In this manner, a continuous solid thermal path is defined between the PCB and the upper wall, facilitating conductive heat transfer to the surface.

It may be advantageous if the potting material is provided such that it also at least partially covers an edge surface of the PCB, which edge surface extends between (connects) the first main surface and the second main surface. This ensures that the PCB is completely surrounded by potting material, further reducing the possibility of moisture ingress.

With respect to the lighting module housing, it may comprise a side wall which in combination with an upper wall of the lighting module housing defines a cavity.

With respect to the lighting elements, the lighting elements may each comprise an LED.

In a preferred set of embodiments, the one or more lighting elements may each comprise an Infrared (IR) or Near Infrared (NIR) lighting element. IR and NIR have good tissue penetration depth and efficient heating performance. The one or more lighting elements may each include an LED configured to emit light having a wavelength primarily in a range from 915nm to 965 nm. However, lighting elements in the visible spectrum may also be considered, in particular at the low frequency red end of the visible spectrum.

In some embodiments, a light transmissive material (comprised of the upper wall of the lighting module housing) and/or a potting material having at least one light transmittance peak in the light wavelength range of 800nm-1050nm may be provided. This may be used in combination with providing a lighting element adapted to generate a light output in a corresponding wavelength range (wavelegnth band). In this example case, this would mean that the lighting element is adapted to produce a light output in the infrared range, in particular the high frequency end of the infrared range, adjacent/overlapping the red end of the visible spectrum.

In some embodiments in which the one or more lighting elements of the lighting module each comprise an LED, the one or more LEDs are each configured to emit light having a wavelength primarily in the range of 525nm-575nm, in the range of 675nm-725nm, or in the range of 775nm-825 nm. With respect to each wavelength range described herein, the term "predominantly" means that at least 80%, preferably at least 90%, and more preferably at least 95% of the optical power of each LED is provided by wavelength components within the respective wavelength range. The light-heat simulation is performed in consideration of the wavelength-dependent optical characteristics of the epidermis and dermis of human skin and the wavelength-dependent electric-to-light energy conversion efficiency of the LED. The simulations have shown that in order to achieve a predetermined thermal depth distribution in human skin over a predetermined period of time, the electrical power required when using LEDs emitting predominantly in one of the three wavelength ranges mentioned above is significantly lower than when using LEDs emitting predominantly in the IR or NIR wavelength range.

In some embodiments, the lighting module housing may be made entirely of a light transmissive material. This has the following advantages: the housing wall itself contributes to coupling out light of the lighting element to the light output surface. In some cases, the light transmissive material may be translucent rather than transparent to help keep the interior of the housing hidden from direct view of a user when viewing the light output surface. In some examples, the lighting module further comprises a visible light illuminating element, and wherein the housing facilitates coupling visible light to the light output surface.

In some embodiments, the lighting module housing may be provided as a single piece injection molded polymer structure.

In a preferred arrangement, the lighting module housing comprises a skin contact surface arranged to be in contact with the skin of the user during operation of the shaving unit, and wherein the skin contact surface delimits one or more openings within which a respective one of the one or more hair cutting units (the aforementioned) is arranged such that each of the one or more hair cutting units is completely surrounded by the skin contact surface. In this example, the previously mentioned light output surface is part of a skin contact surface of the lighting module housing. It may actually form the whole of the skin contact surface or may be only a sub-part thereof, e.g. a light output window provided in the skin contact surface.

In some examples, the shaving unit comprises at least two hair cutting units, and wherein the light output surface of the illumination module extends at least in the area of the skin contact surface between the hair cutting units. In this way, the heating effect from the illumination module is conducted and radiated to the area of the skin contact surface which, in normal use, leads or tails (trail) the two hair cutting units, respectively, when the user slides the shaver unit across his skin. Thus, a warming effect is applied to the skin area actively engaged by the shaving unit.

With respect to the potting material, this may include a glue resin, such as silicon or epoxy, in some examples.

In some examples, the potting material may include a light transmissive base potting material and ceramic particles embedded in the base potting material, the ceramic particles having a size smaller than that of the light emitted by the lighting moduleThe size of the wavelength of light emitted by the one or more lighting elements. The base potting material may include a resin, such as silicon or epoxy, silicone cured gel, or other epoxy mixture. Examples of suitable ceramic particulate materials include TiO ₂ 、Al ₂ O ₃ BeO, alN, and SiC. The ceramic particles embedded in the base potting material improve the heat transfer from the lighting elements via the potting material to the light output surface of the lighting module contacting the skin during operation of the shaving unit. At the same time, the ceramic particles improve the spreading of the light generated by the lighting element over the light output surface of the lighting module by optical scattering. As a result, heat transfer loss is reduced, and hot spots of heat generated at the light output surface due to uneven distribution of light are largely prevented. Since the size of the ceramic particles is smaller than the wavelength of the light emitted by the light emitting element, the light scattering by the ceramic particles is mostly forward.

With regard to the electrical arrangement of the lighting module, the lighting module may comprise one or more electrical connection members electrically connected to the PCB and extending from the second main surface (opposite side) of the PCB through and out of the potting material. Thus, they may extend outwardly (i.e. in a direction away from the light output surface) from the rear side of the lighting module.

As regards the one or more hair cutting elements, they may each comprise: an external cutting member having a plurality of hair entry openings; and an inner cutting member having a plurality of cutting elements, the inner cutting member being covered by the outer cutting member and being movable relative to the outer cutting member.

Another aspect of the invention provides an electric shaver comprising a shaving unit according to any of the embodiments described above (or as further described later in this disclosure). The electric shaver further comprises a shaver body coupled (e.g. releasably) to the shaving unit for driving the one or more hair cutting units.

The shaver body may comprise an electric motor for driving the cutting unit of the shaving unit.

Another aspect of the invention is to provide a method for a shaving unit of an electric shaver. The method comprises a sub-process of providing a lighting module, the sub-process comprising the steps of:

providing a lighting module housing comprising: an upper wall comprising a light output surface; and a sidewall that, in combination with the upper wall, defines a cavity of the lighting module housing, wherein the upper wall has an inner surface facing into the cavity;

providing a lighting unit comprising a PCB and one or more lighting elements mounted to a first major surface of the PCB,

disposing a layer of light-transmissive potting material on an inner surface of the upper wall;

placing the lighting unit on the layer of potting material in the cavity with the first major surface of the PCB facing the upper wall such that the first major surface of the PCB is wetted by the potting material and the lighting elements are each encapsulated by the potting material;

providing a further layer of potting material over the lighting unit to cover a second major surface of the PCB opposite the first major surface, whereby the lighting unit is fully encapsulated by the potting material; and

and arranging an encapsulating material.

The method further comprises the step of including the lighting module as part of a shaving unit such that the light output surface is in contact with the skin of the user when the shaving unit is applied to the skin for shaving during operation of the shaving unit. This may be done at any stage of the manufacturing process. For example, if the lighting module housing is provided integrated in a support structure (e.g. coupled to the previously mentioned support member), this may be inherently achieved at least in part by performing the above-mentioned steps of forming the lighting module, which in combination with the lighting module will form the shaving unit. Alternatively, it may be a separate step performed after building the lighting module, wherein the lighting module is inserted or integrated in the shaving unit structure, e.g. by mechanically coupling the lighting module with other components of the shaver unit.

These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.

Drawings

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

fig. 1 shows a perspective view of the exterior of an exemplary electric shaver according to one or more embodiments of the present invention;

fig. 2 shows a perspective cross-sectional view of a shaving unit according to an aspect of the present invention;

fig. 3 shows a cross-sectional view of an illumination module of a shaving unit according to one or more embodiments of the invention; fig. 4 shows an internal partial cross-sectional view of a lighting module housing according to one or more embodiments of the present invention;

fig. 5 shows another cross-sectional view of a lighting module according to one or more embodiments of the invention;

fig. 6 shows a stage of an example method of manufacturing a lighting module according to one or more embodiments of the invention;

fig. 7 shows an example of a first and a second phase of operation of a lighting module according to an aspect of the present invention;

FIG. 8 shows skin temperature profiles corresponding to discomfort and injury to a subject;

fig. 9 shows an exemplary optical output profile provided by an exemplary spatial arrangement of lighting elements in a lighting module according to at least one embodiment of the present invention;

FIG. 10 illustrates an exemplary drive circuit for controlling a lighting module using sensor feedback from a temperature sensor;

fig. 11 shows an undesired visible light output of a lighting module in an electric shaver provided without an optical arrangement for modifying the visible light profile;

fig. 12 shows an example lighting module in an electric shaver without an optical arrangement for modifying the visible light profile;

fig. 13-15 show in cross-section an exemplary illumination module in a shaving unit according to the invention with an optical arrangement for providing light guidance of a visible light output;

fig. 16 shows a modified visible light profile provided at a light output surface of a lighting module according to one or more embodiments of the invention;

fig. 17 shows a perspective view of a part of an optical arrangement in a lighting module according to one or more embodiments of the invention;

fig. 18 shows an exploded view of an exemplary shaving unit comprising an optical arrangement according to the present invention;

fig. 19 shows another embodiment of a lighting module having an optical arrangement integrally formed by a housing of the lighting module;

fig. 20 shows an example visible light output provided by the lighting module of fig. 19;

fig. 21 shows a PCB portion of an exemplary lighting module according to the present invention;

fig. 22 shows the positioning of the lighting element of the lighting module of fig. 21 relative to the light output surface of the lighting module; and

fig. 23 shows an example light directing member of the lighting module of fig. 21.

Detailed Description

The present invention will be described with reference to the accompanying drawings.

It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the devices, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the present devices, systems, and methods will become better understood with regard to the following description, appended claims, and accompanying drawings. It should be understood that the figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the figures to indicate the same or similar parts.

The present disclosure generally relates to a shaving unit and/or an electric shaver having an illumination module for providing an optical heating function at a skin contact surface of the shaving unit. At least one aspect of the invention relates to an encapsulation device for components of a lighting module by means of a potting material encapsulating a carrier on the upper side and the lower side on which a lighting element is mounted.

Fig. 1 shows a first perspective view of a visible exterior of an exemplary shaving unit 10 for an electric shaver 100 according to at least one embodiment of the present invention. In the illustrated example, the electric shaver 100 is of the rotary type (although this is not essential) and comprises a body 110 and a shaving unit 10, the body 110 being intended to be held by a user of the shaver 100, the shaving unit 10 being intended to contact a portion of skin to be subjected to a shaving action. The body 110 of the shaver 100 is also commonly referred to as a handle, and the shaving unit 10 of the shaver 100 is also commonly referred to as a shaving head. It is practical if the shaving unit 10 is detachably or hingedly mounted to the main body 110 for various reasons, such as a need for maintenance and/or cleaning of the shaving unit 10, a need to replace the shaving unit 10 with another type of functional unit, and the like. The shaving unit 10 comprises a plurality of hair-cutting units 12, in the example shown three in number. In the shown example, the hair cutting elements 12 are arranged in a substantially triangular form. When the electric shaver 100 is used to subject a portion of skin to a shaving action, the actual process of cutting off hairs protruding from the portion of skin takes place at the location of the hair-cutting unit 12. For supporting the hair cutting unit 12, the shaving unit 10 comprises a support member 22, in this example the support member 22 serves as a base member of the shaving unit 10.

Each hair cutting unit 12 comprises a combination of an external cutting member 120, which is generally of cup-shaped design, and an internal cutting member (not shown), which is equipped with at least one hair cutting unit and which is at least partly accommodated inside the internal cutting member. The outer cutting member 120 has hair entry openings 122 in the annular cutting track surface. During a shaving action, hairs extending through the hair entry openings 122 and protruding into the interior of the external cutting member 120 are cut off as soon as they encounter the hair cutting elements of the internal cutting member. When the inner cutting member is actuated to rotate and a portion of the skin is actually contacted by the outer cutting member 120 at the position of the cutting track surface, a shaving action as described above may be performed. The activation of the internal cutting member may be performed in a known manner by a drive mechanism of the shaver 100 comprising an electric motor. The body 110 may optionally house a drive mechanism along with a local power source (e.g., a battery). When the combination of the external cutting member 120 and the internal cutting member is moved over the portion of the skin while the internal cutting member is driven in rotation, it is achieved that hairs protruding from the portion of the skin are caught in the hair entry openings 122 of the external cutting member 120 and are severed at this location.

It is noted that the invention also encompasses electric shavers and shaving units having one or more hair-cutting units of different types as described above. In particular, the invention also covers electric shavers and shaving units having a hair cutting unit with an inner cutting member arranged to reciprocate linearly with respect to an outer cutting member.

The upper surface of the shaving unit 10 comprises a skin contact surface 54, at least a portion of which skin contact surface 54 is formed or formed by the light output surface 36 of the illumination module integrated inside the shaving unit 100, as will be further described below.

It should be noted that the foregoing general information regarding the electric shaver 100 according to the first embodiment of the present invention, the description of which will be below, is compatible with (although not necessarily essential to) all subsequently described embodiments of the present invention.

Fig. 2 illustrates an exploded view of an example shaving unit 10 in accordance with one or more embodiments. In particular, fig. 2A shows a close-up partially cut-away internal view of the shaving unit 10, while fig. 2B shows a wide exploded view of the shaving unit. Fig. 3 shows a cross-section through the shaving unit 10 along the line a shown in fig. 3. Fig. 4 shows a lower inside view of a part of the shaving unit 10. Fig. 5 shows a cross-sectional view through the shaving unit 10 along the line B shown in fig. 5.

The shaving unit 10 includes a lighting module 14, the lighting module 14 including a lighting module housing 18 that houses one or more lighting elements 20. In this example, the lighting module housing 18 is arranged on a support member 22 of the shaving unit 10 and forms part of the shaving unit housing. In particular, the lighting module housing 18 forms an upper part of the shaver unit housing, and the support member 22 serves to support the one or more hair cutting units 12 and the lighting module 14. The lighting module housing 18 defines one or more openings 56, a respective one of the one or more hair cutting units 12 in the shaving unit 10 being disposed within the opening 56. However, such formation is not necessary. For example, the lighting module may be a completely separate structural unit integrated in a separate housing of the shaving unit; the described design imparts additional structural efficiency but is not essential to the inventive concept.

The lighting module 14 further comprises electrical connection pins 23 extending downwardly from the lighting module 14 for electrically contacting complementary electrical contacts in the body 110 for providing an electrical connection between the lighting module 14 and the shaver body 110 in the assembled configuration.

The lighting module housing 18 defines an interior cavity 32, and the lighting element 20 is disposed in the cavity 32. The cavity 32 is covered by an upper wall 34 of the lighting module housing at the skin facing side of the lighting module housing 18. The upper wall comprises a skin-facing light output surface 36, via which light output surface 36 the light generated by the illumination element 20 is exposed to the skin during operation of the shaving unit. The upper wall 34 is made of a light transmissive material, wherein the light transmissive material provides a light output surface. In other examples, the upper wall 34 may contain the light output surface as a sub-region within a wider wall area, such that the light output surface forms a light output window through the upper wall.

In the example shown, the lighting module housing 18 further includes side walls 50a,50b that define the cavity 32 in combination with the upper wall 34 of the lighting module housing 18.

In the illustrated example, the upper wall 34 of the lighting module housing 18 at least partially defines a skin contact surface 54 for the shaving unit 10, and the aforementioned light output surface 36 comprised in the upper wall 34 is arranged to contact the skin during operation of the shaving unit.

The lighting module housing 18 may be a one-piece structure in some examples. It may be an injection molded part. It may be formed of plastic.

The lighting module 14 comprises a carrier, for example a Printed Circuit Board (PCB) 38, arranged in the cavity 32, wherein the lighting element 20 is mounted to a first main surface 42 (best shown in fig. 3) of the PCB facing the upper wall 34 of the lighting module housing 18, such that the lighting element 20 is in optical communication with the light output surface 36 during operation of the shaving unit 10.

The cavity 32 includes a light-transmissive potting material 40 (best shown in fig. 3) covering a first major surface 42 of the PCB, encapsulating the lighting element 20. The potting material 40 extends between the first major surface of the PCB38 and the upper wall 34 of the lighting module housing 18. The potting material 40 also covers a second major surface 44 of the PCB38 (i.e., the opposite or underside of the PCB 38) opposite the first major surface 42. The potting material 40 thus encapsulates the PCB38 on all major sides. The potting material provides a thermal conduction path in the lighting module 14 between the lighting element 20 and the light output surface 36, thereby bringing the lighting element 20 into thermally conductive contact with the light output surface 36. The potting material 40 also provides a water-resistant function, as explained further below.

The lighting element 20 is adapted to provide a skin heating effect at the light output surface 36 of the lighting module housing 18 when in contact with the skin during operation. That is, when the lighting elements 20 of the lighting module 14 are activated during a shaving action, it is achieved that the skin is subjected to a thermal stimulus, which may result in an improvement of the skin condition or appearance and/or an improvement of the shaving comfort. In the example shown, this is achieved by including one or more Infrared (IR) or Near Infrared (NIR) lighting elements 62 in the lighting element 20. This provides a light output having a major frequency component in the IR or NIR range of the Electromagnetic (EM) spectrum. The IR or NIR range has a particularly good penetration depth into the skin. The light transmissive material of the upper wall 34 of the lighting module housing 18 and/or the potting material 40 may have a light transmission distribution with at least one peak in the light transmission distribution in the light wavelength range of 800nm-1050nm to maximize the optical coupling from the IR or NIR lighting element 20, 62 to the light output surface 36.

In addition to the optically induced skin heating effect of the IR or NIR lighting element 20, 62 caused by optical absorption of IR or NIR light emitted by the lighting element 20, 62 by skin tissue, the lighting element 20 also provides a conduction induced skin heating effect caused by the thermal conduction path between the lighting element 20 and the light output surface 36 provided by the potting material 40. As a result of the heat conduction path, the light output surface 36 is heated by thermal energy, which is dissipated by the lighting element 20 due to their limited electro-optic conversion efficiency. Thus, during shaving, the skin is also conductively heated due to its thermally conductive contact with the light output surface 36. The combined optically and conductively induced skin heating effect provides a high skin heating efficiency of the illumination module 14 in the shaving unit 10.

It is not necessary that the illumination element 20 comprises an IR or NIR illumination element, as light induced heating is feasible with other parts of the EM spectrum, for example with visible light illumination elements. In some cases, an optical component, such as a lens, may be used in conjunction with the visible light illuminating element to focus or concentrate the light output, thereby increasing the thermal power of the light at the light output surface.

Furthermore, although at least one function of the lighting module is to provide a heating effect, the light emission may additionally provide other beneficial effects to the skin tissue. For example, blue visible light is known to be beneficial for acne treatment, and red visible light is known to be beneficial for stimulating wound healing and treating skin inflammation.

In the example shown, the set of lighting elements 20 includes, in addition to the IR or NIR lighting element 62, one or more visible light lighting elements 64 for providing a visible light indication of activation of the IR or NIR lighting element. They may be configured to be active when the IR or NIR lighting elements are active (active), or to be electrically supplied by active control of the controller, or by a parallel wiring arrangement with the IR/NIR lighting elements 62 in the circuit arrangement. However, in further examples the visible light illuminating element may be omitted.

Where a visible light illuminating element 64 is provided, the light transmissive material of the upper wall 34 of the lighting module housing 18 and/or the potting material 40 may have at least one additional peak in light transmittance in the light wavelength range of 450nm-700nm to maximize light coupling from the visible light illuminating element 64 to the light output surface 36.

In some examples, each lighting element 20 of the one or more lighting elements may include an LED. In the example of the IR or NIR lighting element 20 as described before, the LEDs may be configured to emit light having a wavelength predominantly in the range of 915-965 nm.

In some examples where the one or more lighting elements 20 each comprise an LED, the one or more LEDs may each be configured to emit light having a wavelength primarily in the range of 525nm-575nm, in the range of 675nm-725nm, or in the range of 775nm-825 nm. The light-heat simulation is performed in consideration of the wavelength-dependent optical characteristics of the epidermis and dermis of human skin and the wavelength-dependent electric-to-light energy conversion efficiency of the LED. The simulations have shown that in order to achieve a predetermined thermal depth distribution in human skin within a predetermined period of time, the electrical power required when using LEDs emitting mainly in one of the three wavelength ranges mentioned above is significantly lower than when using LEDs emitting mainly in the IR or NIR wavelength range. In particular, the predefined thermal depth profile comprises a first predefined average temperature (e.g. 41.7 ℃) over the epidermis thickness (200 μm) and a second predefined average temperature (e.g. 39.0 ℃) over the dermis thickness (1800 μm). For the simulations, the conversion efficiencies of the LEDs emitting in the wavelength ranges of 525nm-575nm,675nm-725nm,775nm-825nm, and 915nm-965nm (IR) were assumed to be about 13%, 38%, 32%, and 30%, respectively. According to the simulation, the electric power required for the LEDs emitting in the wavelength ranges of 525nm-575nm,675nm-725nm, and 775nm-825nm seems to be 2.46W, 2.22W, and 3.03W, respectively, compared with the electric power of 3.9W required for the IR LEDs. Thus, using LEDs emitting in any of these three wavelength ranges significantly reduces the battery power required by the battery in the body 110 powering the lighting module 14 when compared to using IR or NIR LEDs. The lighting module 14 comprises one or more electrical connection members 23 (connection pins), which electrical connection members 23 are electrically connected to the PCB38 and extend from the second main surface 44 of the PCB through the potting material 40 and out of the potting material 40.

With respect to the potting material 40, this serves the dual function of inhibiting moisture or other contaminants (e.g. dirt or dust) from entering the cavity 32, and also serves the function of providing a thermal coupling from the lighting element 20 to the light output surface 36 (and thus to the skin surface during normal use of the electric shaver 100).

Preferably, the potting material 40 extends uninterrupted from the first major surface 42 of the PCB38 to the upper wall 34 of the lighting module housing 18. In other words, it defines at least one continuous solid material path from the first main surface of the PCB to the upper wall 34 of the lighting module housing 18. This ensures a solid heat conduction path from the lighting element 20 on the first main surface 42 of the PCB38 to the light output surface 36 in the upper wall 34 of the lighting module housing 18, thereby optimizing the heat conduction.

Preferably, the manufacturing of the lighting module 14 should be such that air bubbles in the potting material 40 are minimized or even eliminated, as the air bubbles reduce the overall thermal conductivity of the thermally conductive path from the PCB first main surface 42 to the light output surface 36. The bubbles also adversely affect the uniformity of the temperature distribution. A particularly advantageous manufacturing method will be outlined later in this disclosure.

Preferably, the potting material 40 extends between the PCB38 and the light output surface 36 as a continuous, unitary structure, i.e., without interruption. At least it should include at least one continuous solid path from the PCB38 to the light output surface 36.

During assembly of the lighting module 14, the PCB38 should preferably be completely wetted by the potting material 40 on both of its main surfaces 42, 44.

To effectively prevent moisture ingress, there should be a chemical bond or adhesion between the potting material 40 and the first and second major surfaces 42, 44 of the PCB 38. There should also be a chemical bond between the potting material 40 and the inner surfaces of the cavity 32 (i.e., the inner surfaces of the upper wall 34 and the sidewalls 50a,50 b).

In order to be effectively waterproof, there should preferably also be a chemical adhesion or adhesion between the encapsulating material 40 and the electrical contact pins 23. This helps to prevent water from entering via the surface of the electrical contact pin 23.

Preferably, the potting material 40 at least partially covers an edge surface 46 of the PCB38 extending between the first and second major surfaces 42, 44.

Suitable materials for the potting material 40 may include, for example, a glue resin, such as silicon or epoxy. However, generally any encapsulation or filling material may be used. Preferably, the material is a material that exhibits the following properties in the functional temperature range of the lighting module 14: (a) no phase change; (b) Does not (substantially) change its mechanical, thermal or optical properties; (c) shows no discoloration. The functional temperature range may be, for example, between-10 ℃ and 100 ℃, with the actual target operating temperature typically being about 40 ℃ to 60 ℃. The wider temperature range allows for variations in environmental conditions, for example, the shaver is left outside in a cold environment, or the shaver is left in a hot car in the sun.

Potting material 40 may include a light transmissive base potting material and ceramic particles embedded in the base potting material. In this embodiment, the ceramic particles preferably have a size smaller than the wavelength of the light emitted by the light emitting element 20. The base potting material may include a resin, such as silicon or epoxy, silicone cured gel, or other epoxy mixture. Examples of suitable ceramic particulate materials include TiO ₂ 、Al ₂ O ₃ BeO, alN and SiC. The ceramic particles embedded in the base potting material improve heat transfer from the lighting element 20 to the light output surface 36 of the lighting module 14 via the potting material 40. At the same time, the ceramic particles improve the spreading of the light generated by the lighting element 20 over the light output surface 36 of the lighting module 14 by optical scattering. As a result, heat transfer loss is reduced, and hot spots of heat generated at the light output surface 36 due to uneven distribution of light are largely prevented.

When the size of the ceramic particles is smaller than the wavelength of light emitted by the light emitting element 20, light scattering by the ceramic particles is mostly forward. The density of the ceramic particles may be selected to maximize light scattering and minimize light loss. The optimum particle density depends on the distance between the PCB38 and the light output surface 36 of the lighting module 14.

The size and density of the ceramic particles embedded in the base potting material may vary depending on the location within the cavity 32. The size and density of the ceramic particles may be selected to optimize thermal conduction near the sidewalls 50a,50b of the cavity 32, i.e., at locations outside the primary path of light. In particular, at said locations the size of the ceramic particles may be relatively large and the density of the ceramic particles may be set to a maximum value which the base potting material may comprise. Potting materials having different ceramic particle properties may be separated from each other by transparent partition walls in the cavity 32.

With respect to the optical function of the lighting module 14, optionally, and as shown in fig. 2-4, the lighting module may further include an optical arrangement for producing the visible light output provided by the optional visible light illuminating element 64 at the light output surface 36. In this example, this includes a light directing device 412 configured to direct visible light generated by the visible light illuminating element 64 to at least a region of the light output surface 36 of the illumination module 14. The light directing means 412 may comprise a light directing sheet or film disposed on or over the first major surface 42 (upper surface) of the PCB 38. It may be adhered to PCB38 with an adhesive layer. It may be a light guide sticker (packer). In some examples, this may direct light in a direction having a major directional component parallel to the light output surface 36. Optionally, a light attenuating element may also be provided for suppressing or attenuating the direct light path from each visible light illuminating element 64 to the light output surface 36. Each light attenuating element may be facilitated by a light attenuating layer, for example comprising a light attenuating mask layer deposited on an optically transparent carrier layer disposed on top of the light guiding device. These features will be described in more detail later in this disclosure.

With respect to the optical function of the lighting module 14, in some examples, the lighting module housing 18 may be made entirely of the previously mentioned light transmissive material (the material forming the light output surface 36). It may be optically translucent, e.g. scattering, to prevent direct viewing of the interior of the cavity 32 of the illumination module 14 from the visible surface of the shaving unit 10. This allows the entire body of the lighting module housing 18 to provide the light coupling function from the lighting element 20 to the light output surface 36 and the skin contact surface 54 of the shaving unit 10. The lighting module housing 18 may alternatively be a one-piece injection molded polymer structure.

As mentioned before, the lighting module housing 18 in this example comprises a skin contact surface 54, which skin contact surface 54 is arranged to be in contact with the skin during operation of the shaving unit 10. The light output surface 36 forms at least a part of the skin contact surface 54. The skin contacting surface 54 defines one or more openings 56, a respective one of the one or more hair-cutting elements 12 of the shaving unit 10 (when assembled) being disposed within the opening 56. In the shown example, each of the one or more hair cutting elements 12 is completely surrounded by the skin contact surface 54, although this is not essential (e.g. in a foil-shaver configuration, the skin contact surface may extend around only a subset of the sides of each elongated hair cutting element).

As shown in fig. 2, the light output surface 36 of the illumination module 14 extends at least in the area of the skin contact surface 54 between each of the plurality of hair cutting elements 12.

In the example of fig. 2-5, all lighting elements 20 are mounted to a first major surface 42 of the PCB, which first major surface 42 faces the light output surface 36. However, this is not essential. In some embodiments, one or more lighting elements 20, particularly one or more visible light lighting elements, may be mounted to the second major surface 44 (i.e., the surface of the underside) of the PCB.

Fig. 4 shows an underside view of the PCB38 of the lighting module according to this example. Fig. 4 shows a partial cross-sectional view showing components on the second major surface 44 (i.e., the underside surface) of the PCB 38. In this example, a plurality of visible light illuminating elements 64 are disposed on the second major surface of the PCB. The lighting elements may be provided in addition to, or instead of, visible light illuminating elements on the above-mentioned first major surface 42 of the PCB 38.

In some embodiments, at least one temperature sensor 350, such as a thermistor (see FIG. 5), may also be disposed on the PCB 38. This is preferably located adjacent at least one of the IR or NIR lighting elements 62. This may be used by a controller for adjusting the power level of the IR or NIR lighting element 62 for adjusting the temperature at the light output surface 36. However, this feature is optional and may be omitted.

The lighting module may include one or more additional electrical components, such as one or more resistors 66, mounted to the PCB38, as shown in fig. 5.

Fig. 6A-6D schematically illustrate steps of a suitable manufacturing method of forming at least a portion of the lighting module 14 for the shaving unit 10 shown in fig. 2-5. The steps shown in fig. 6A-6D are for assembling at least a portion of the lighting module 14.

The method includes (fig. 6A) providing 210 a lighting module housing 18 including an upper wall 34 and sidewalls 50a,50b, the upper wall 34 including a light output surface 36, the sidewalls 50a,50b in combination with the upper wall 34 defining a cavity 32 of the lighting module housing 18. The upper wall 34 has an inner surface 72 facing the cavity 32.

The method further comprises (steps not explicitly shown in fig. 6A-6D) providing a lighting unit comprising a PCB38 and one or more lighting elements 20 mounted to the first major surface 42 of the PCB 38. The lighting elements 20 may include IR or NIR lighting elements 62 and/or visible light lighting elements 64. The lighting unit may further comprise an optical arrangement, for example comprising a light guiding means 412 provided on the first main surface 42 of the PCB 38.

The method further includes (fig. 6B) disposing 230 a layer 41a of light-transmissive potting material 40 on the inner surface 72 of the upper wall 34. The inner surface 72 is preferably completely wetted by the layer of potting material.

The method further comprises placing 240 the aforementioned lighting unit comprising the PCB38 and the lighting elements 62, 64 onto the layer 41a of potting material 40 in the cavity 32, with the first major surface 42 of the PCB38 facing the upper wall 34, such that the first major surface 42 of the PCB is wetted by the potting material 40 and the lighting elements 62, 64 are each encapsulated by the potting material.

The method further comprises providing 250 a further layer 41b of potting material 40 on the lighting unit to cover a second major surface 44 of the PCB38 opposite the first major surface 42, whereby the lighting unit is completely encapsulated by the potting material on the first and second major surfaces 42, 44 of the PCB 38. The potting material also preferably covers the side edges 46a, 46b of the PCB 38.

The method also includes disposing a potting material.

The result of this method is: a PCB38 on which the lighting elements 62, 64 integrated in the lighting module housing 18 are carried, the lighting module housing 18 being sealed and wetted on all sides by the potting material 40. The potting material has a chemical bond to all portions in contact therewith.

The method further comprises the step of including the lighting module 14 as part of the shaving unit 10 such that the light output surface 36 is in contact with the skin of the user when the shaving unit is applied to the skin for shaving during operation of the shaving unit. This step may be achieved by assembling the illumination module 14 on the support member 22 of the shaving unit 10 during subsequent manufacturing processes of the shaving unit 10.

The setting step may be performed as a single step after both layers 41a, 41b of potting material have been deposited, or a first setting step may be performed after depositing the first layer 41a and positioning the lighting unit, followed by a second setting step after depositing the second layer 41b on the lighting unit.

The above method provides a particularly efficient encapsulation and also minimizes bubble formation in the layer of potting material to achieve optimal thermal conductivity and temperature uniformity of the potting material.

Instead of depositing the potting material 40 in a two layer deposition process, a single deeper layer of potting material may be deposited in the cavity 32, and then the lighting unit immersed in the potting material. However, this may be less practical, especially when performed in mass production.

Preferably, the potting material 40 is a material that provides at least 90% light transmittance of light from the IR or NIR lighting element 62 to the exterior of the lighting module 14 (via the light output surface 36).

Alternatively, the lighting module housing 18 may be formed of a light transmissive material, wherein preferably the material provides at least 70% light transmittance of light from the IR or NIR lighting element 62 to the exterior of the lighting module 14.

Preferably, the potting material 40 and the lighting module housing 18 have a thermal conductivity of at least 0.2W/mK.

Preferably, the specific heat capacity of the potting material 40 is at least 800J/KgK.

Preferably, the lighting module housing 18 has a specific heat capacity of at least 1250J/KgK.

Alternatively, the operating temperature range of the IR or NIR LED may be between-10 ℃ and 100 ℃.

Alternatively, the operating temperature range of the potting material 40 may be between-10 ℃ and 100 ℃.

Alternatively, the operating temperature range of the lighting module housing 18 may be between-10 ℃ and 80 ℃.

Preferably, the potting material 40 should be chemically resistive and should be robust to frequent temperature cycling in terms of its material properties.

The electric shaver 100 may further comprise a controller (not shown) for controlling the lighting elements 20. The controller may be accommodated in the shaver body 110. The controller may include at least one processor. The controller may be arranged to receive signals or receive data from one or more sensors (e.g. temperature sensors) included on the PCB.

In accordance with at least one set of embodiments of the present invention, a novel control scheme may be provided for the lighting element 20 to optimize the temperature regulation of the light output surface 36. The shaving unit 10 in this example may be the same as or similar to the shaving units described above. In particular, all features of the electric shaver 100 and the shaving unit 10 described above are compatible with this set of embodiments of the invention, but some features may be omitted. For example, the potting material described above is not necessary for this set of embodiments of the invention.

According to one or more embodiments, an electric shaver 100 is provided, the electric shaver 100 comprising a shaver unit 10 (e.g. as described above), and comprising a controller operatively coupled with the lighting module 14 and adapted to control the lighting elements 20 in a driving scheme comprising at least a first phase and a second phase. The controller may be accommodated in the shaver body 110. The driving scheme comprises an initial heating phase triggered upon activation of the lighting module, wherein the lighting elements 20 are driven at an initial power setting. The driving scheme further comprises an operating phase after the initial heating phase, wherein the lighting element 20 is driven at an operating power setting. The maximum power value of the working power setting is lower than the power value of the initial power setting. The initial heating phase may be directed to a predetermined target temperature of the light output surface 36. This may be done implicitly (blindly) by executing a predetermined power profile having a determined duration that is known or predicted to result in the target temperature. Alternatively, it may be done actively by using input from a temperature sensor as feedback to direct one or both of the power setting and the duration of the initial heating phase.

In some examples, during the operational phase, the temperature of the light output surface may be controlled to be maintained at a predetermined temperature by active control of the operational power setting. This may be done, for example, using a temperature sensor to provide active feedback.

The initial heating phase has a higher (initial) power setting to quickly heat the light output surface 36 to the target temperature required for operation. This improves the convenience for the user who has to wait for a short duration before using the shaver. However, this initial power setting may provide a light output at the light output surface 36 that exceeds what may be comfortable or safe for the user if the light output is maintained throughout the shaving process. Thus, the second (operational) phase reduces the (time-averaged) power setting, so that the temperature can be maintained, but the light output is comfortable and safe for the user.

By way of further illustration, and not intended to limit the scope of the invention, examples of the first and second stages are schematically illustrated in the graph of fig. 7. This shows an initial heating phase (1) and a subsequent operating phase (3), and a brief intermediate transition phase (2) separates them in time, during which the power setting is reduced from the initial power setting to a lower operating power setting. FIG. 7 shows the optical power density (line A; unit: mW/cm) at the light output surface during each mode ² ) And at the light output surface 36 during each modeTemperature (line B; unit:. Degree. C.), both as a function of time (unit: seconds).

With respect to the temperature that should be targeted in the initial heating phase 310 and the operating phase 320, the temperature may vary as needed and is typically based on comfort and safety thresholds desired by the user. Fig. 8 provides an exemplary summary of different application skin temperature profiles (i.e., the allowed maximum skin temperature as a function of contact time with the heat source) that cause discomfort and injury. Line C corresponds to an intact skin thickness burn. Line D corresponds to a local skin thickness burn. Line E corresponds to discomfort.

In at least one set of preferred embodiments, the predetermined temperature for the initial heating phase and the operating phase may be in the range of 40 ℃ to 50 ℃. More specifically, the predetermined temperature may be in the range of 41.8 ℃ to 42.2 ℃, in the range of 44.8 ℃ to 45.2 ℃, or in the range of 47.8 ℃ to 48.2 ℃. This temperature range is based on the following considerations.

Since the light output surface 36 contacts the skin during use, this temperature range is targeted to temperatures within the comfort tolerance desired by the user. For example, the normal face temperature is about 36 ℃ (where this may vary depending on environmental conditions). The average human perception sensitivity is about 2 ℃. The addition of this 2 ℃ results in 38 ℃ so that the heating effect is perceptible. Furthermore, a suitable minimum boundary range may be between 42 ℃ and 43 ℃ in view of the maximum sensory benefit to the user that the temperature should be the maximum possible temperature within the safe and comfortable limits. This temperature has been found to be at a level that is still comfortable for the user and is effective in providing skin benefits.

The upper boundary temperature may be selected based on perception and preference and compliance with safety criteria. This indicates that the skin must not have a maximum above 48 ℃. For example, referring to fig. 8, it can be seen from line E that for extended contact times of 10 seconds or more, the temperature of 48 ℃ is just below the lowest temperature that would cause discomfort to the user. Assuming that the system has a temperature accuracy of 0.05 deg.C, the upper temperature limit may be set to 47.95 deg.C.

Since the user's preferences for the target temperature may differ, the electric shaver in some embodiments may comprise an input member configured to enable a user of the electric shaver to select the predetermined temperature. The upper cover may be set at a temperature that can be selected, for example 48 ℃ in some examples, so that the user cannot exceed safety limits. The input component is operatively coupled with the aforementioned controller. There may be a plurality of predetermined temperature settings from which the user may select. Alternatively, the controller and input means may allow the user to freely select any target temperature within certain temperature boundaries.

As one illustrative example, a set of example predetermined temperature settings for a target (predetermined) temperature selectable using an input member may be as follows:

TABLE 1

The initial heating phase 310 may be triggered automatically when the device is switched on. During the initial heating phase, the optical power remains fixed at a relatively high setting and the temperature of the light output surface 36 rapidly increases. When the predetermined target temperature is reached, the controller moves to the operational stage 320. Temperature feedback may be used to vary the light output in the operational phase 320 in order to maintain a predetermined target temperature steady (steady state phase).

In order to accelerate the heating of the light output surface 36, the initial power setting during the initial heating phase 310 is set higher than the maximum power value used during the subsequent operating phase 320. By increasing the power, the optical power density at the light output surface 36 is increased, thereby increasing the rate of heat transfer to the light output surface 36. Accelerated heating must be balanced with the comfort and safety described above. Further to manage the maximum temperature of the target, the maximum optical power density provided by the lighting element 20 at the light output surface 36 is preferably managed.

The purpose in this regard may be to seek to limit the total light energy density (in J/cm) delivered to any point of the user's skin over successive periods of time during use of the device ² In units) ofNot exceeding a predetermined safety threshold. The continuous application of optical energy to any one point on the skin means a cumulative thermal exposure at that point, which can cause discomfort or burns if the total optical energy density delivered over a continuous period of exposure is too high. The total optical energy density delivered to a user tissue region within any continuous time window is the time-averaged optical power density (W/cm) delivered over the region (via the light output surface in contact with the region) ² ) And the length of time of the time window. Since the length of time that the user applies the light output surface to a single tissue spot cannot be directly controlled, it is advantageous to control the maximum optical power density provided at the light output surface during the initial heating phase according to an assumed worst case user scenario related to the period of time that the user applies the light output surface to a single tissue region.

The optical power density at the light output surface may generally vary as a function of position at the light output surface. According to one or more embodiments, the heating phase may be configured such that, at a point or region of the light output surface at which the optical power density has a maximum during the initial heating phase, said maximum in optical power density is at 325mW/cm ² And 360mW/cm ² In the meantime.

This is a safety constraint based on the assumption of a worst case user scenario in which the user applies the light output surface to a single fixed point on his tissue for 10 seconds. Studies have shown that in normal use of any razor, 10 seconds is a conventional upper limit for the user to hold the razor at any point before proceeding. Therefore, it is reasonable to assume a maximum exposure time of 10 seconds. Furthermore, this time limitation can be implemented by making the duration of the initial heating phase 10 seconds (after which the operation phase is triggered, reducing the light power at the light output surface), so that it is not possible for the user to exceed an exposure time of 10 seconds at the initial power setting. If the maximum optical power density at any spatial point/area on the light output surface is at the upper end of the above range, i.e. 360mW/cm ² And the user applies the light output surface to the same static point for a maximum of 10 seconds, this will correspond toTotal delivered optical energy density of 3.6J/cm exposed to tissue at the quiescent point ² . This ensures compliance with the standard safety regulation of IEC/EN 62471 "photobiological safety of lamps and lamp systems", which requires 3.6J/cm ² Maximum light energy exposure.

It should be noted, of course, that the above-described range of maximum optical power densities is merely one exemplary implementation and is not intended to limit the inventive concept. For example, the range may be changed if different assumptions are made about the user application time, and/or if the specification constraints are different. For example, the user may be given instructions on the maximum length of time (e.g. 5 seconds or 2.5 seconds) that they should apply the shaver to any one point, and be assumed to follow the instructions. An automatically generated feedback cue (e.g., audible or tactile) may be issued after any static hold of the device at a point for a predetermined length of time.

If this assumption is made, the maximum optical power density at the light output surface may increase beyond the above-mentioned 360mW/cm ² . For example, if the continuous application time to the tissue is not longer than 5 seconds, the maximum time-averaged optical power density at the light output surface during the initial repair phase may be set to be up to 600mW/cm2. If the assumed maximum exposure time is even shorter, the maximum optical power density can be increased even further to 1W/cm at 2.5 seconds ² . The initial heating period may be set to have a length equal to the maximum time period, although the time period may not be long enough to achieve the desired target surface temperature.

It is a design choice where the user is somewhat trusted not to exceed the expected maximum exposure time at a point. For balancing in terms of safety, an assumed exposure time of 10 seconds (according to the user's natural behavior pattern) may be preferred. Thus, according to IEC/EN 62471 standard safety regulations, the temperature of the skin can be controlled to remain below a predetermined maximum temperature (e.g., 48℃.), and the light energy exposure can be maintained at 3.6J/cm ² The following.

The lighting module may generally comprise a spatial arrangement of IR or NIR lighting elements 62, wherein the irradiance (optical power per unit area) provided at the light output surface is different for different lighting elements 62. Irradiance may be different in this regard due to different optical path lengths between different respective IR or NIR lighting elements 62 and the light output surface.

In view of the above, according to one or more embodiments, the lighting module may be configured such that the light beam of at least one of said IR or NIR lighting elements 62 has the highest average optical power density at the light output surface during the initial heating phase compared to the other IR or NIR lighting elements, wherein the initial power is set at a power value such that said highest average optical power density is 325mW/cm ² And 360mW/cm ² In between. The average optical power density provided by the light beam of a given lighting element at the light output surface refers to the average of the optical power densities measured in the cross-section of the light beam at the light output surface during the initial heating phase. It is assumed here that the light beams of the different IR or NIR illumination elements do not overlap at the light output surface. Thus, depending on their location in the lighting module 14, one or more of the IR or NIR lighting elements will provide the highest average optical power density at the light output surface. The initial power setting is such that the maximum average optical power density is 325mW/cm ² And 360mW/cm ² In between. In embodiments where the lighting elements provide overlapping beams at the light output surface, the initial power setting during the initial heating phase should for example be such that the highest optical power density at any position on the light output window is within the above-mentioned range of optical power densities.

The optical power density provided by a given illumination element 62 will depend on the power of the source powering the illumination element, and also on the optical path length from the illumination element to the light output surface.

For example, referring to fig. 9, an example positioning of the IR/NIR lighting element 62 of the (left) example shaving unit 10 relative to the light output surface 36 is shown. The lighting elements 62 are arranged in a plurality (in this case four) of spatial groups or clusters. Each group may include a minimum of one IR/NIR illuminating element 62, but may include more than one IR/NIR illuminating element. The set of illumination elements includes a central group 510, and first, second and third peripheral groups 520a, 520b, 520c. The radiation pattern of a typical IR/NIR LED lighting element 62 is shown in FIG. 9 (right). This indicates that the typical maximum angular range of radiation on each side of the LED perpendicular to the optical axis is 60 degrees.

In view of this, it may be determined that the central group 510 of one or more IR/NIR lighting elements 62 has a greater area of irradiance at the light output surface, has optimal contact with the skin, but has less than 300mW/cm due to the greater distance between the IR/NIR lighting elements as compared to the peripheral group of IR/NIR lighting elements ² Lower average irradiance levels. The greater distance between the central group 510 and the light output surface is due to the slight convex curvature of the lighting module housing 18, the apex of which coincides with the position of the central group of lighting elements.

In this example, in the area between the four sets of IR/NIR illuminating elements 62 (the area between the blue circles), the skin contacting surface is substantially free of radiation from the IR/NIR illuminating elements, so that this area will be exposed to conduction heating only.

The control options for the lighting elements 20 for achieving the initial heating phase 310 and the operation phase 320 will now be discussed in more detail.

With regard to the control of the lighting module 14, the activation of the lighting module 14 may be triggered by activating one or more hair cutting units 12. For example, the activation of the initial heating phase may be triggered by the activation of one or more hair cutting elements (i.e. the switching on of the electric shaver). This simultaneous activation may be achieved by a simultaneous control of the aforementioned controllers of the electric shaver 100, or it may be triggered automatically due to a parallel wiring arrangement between the cutting units 12 and the lighting modules 14.

In addition to or instead of this control configuration, the electric shaver 100 may comprise a further input member (e.g. a switch or other input means) configured to enable a user of the electric shaver to activate and/or deactivate the lighting module 14 independently of the activation of the one or more hair cutting elements 12. This allows the user to select the hair cutting function of the shaver with or without heating function. The electric shaver controller may have a default setting, i.e. to trigger the lighting module by activating the hair-cutting element, but wherein the user may deactivate the lighting module using a further input member.

With respect to the aforementioned predetermined temperature target, temperature sensor 350 may be used to provide temperature feedback to the controller during one or both of the initial heating phase and the operating phase. The temperature sensor may be carried on the same PCB38 that carries the lighting elements 20. For example, the temperature sensor 350 may be mounted to the previously discussed first major surface 42 of the PCB in close proximity to one of the lighting elements (e.g., one of the IR or NIR lighting elements). The temperature sensor 350 can be seen, for example, in the cross-sectional view of fig. 5. Providing a temperature sensor directly adjacent to the lighting element provides the best thermal coupling between the two.

A thermally conductive path between said first main surface 42 of the PCB facing the light output surface 36 and the light output surface 36 is provided by a light transmissive potting material 40 as previously described, the potting material 40 being provided to cover the first main surface 42 of the PCB38, thereby encapsulating the lighting element 20 and the temperature sensor 350. The potting material also provides thermal coupling of the temperature sensor 350 and the light output surface 34 as described above, thereby increasing the accuracy with which the temperature sensor measures the surface temperature.

A portion of one example control circuit is schematically illustrated in fig. 10. The circuit comprises circuit components in the lighting module 14 (in the shaving unit 10) and also in the body 110 of the shaver. In this example, the lighting module comprises the lighting element 20 and further comprises a temperature sensor 350 (e.g. a thermistor). The body 110 includes a controller 86. The controller 86 is configured to control the duration of the initial heating phase. The controller is further adapted to control the power level of the lighting element 20 in dependence on the sensed output from the temperature sensor 350 during the operational phase. For example, the controller is configured in this way to adjust the temperature of the light output surface 36 by controlling the lighting element 20 according to the output from the temperature sensor.

The subject circuit in the illustrated example also includes a battery ("BAT") for powering the lighting module 14, electrical connections to the lighting module for powering the lighting module, and signal connections to the lighting module for receiving a sensed signal from the temperature sensor 350.

Controlling the power level of the lighting element may include varying a duty cycle frequency of a Pulse Wave Modulation (PWM) drive scheme.

To control the lighting module to maintain a desired set point temperature, the lighting module includes a temperature sensor 350, such as a thermistor, for example a Negative Temperature Coefficient (NTC) thermistor.

The controller 86 can sample the temperature sensor 350 signal and this can be processed by the controller 86 to convert the sensor signal to a temperature. The sampling frequency of the temperature sensor is not critical since temperature changes tend to be slow.

The obtained temperature value may be used in a closed loop system to adjust a desired set point temperature.

Safety measures may be added to avoid overheating. For example, if the measured signal is outside a certain operating bandwidth (indicating overheating), the lighting module may be automatically deactivated.

Various temperature control module options are possible. According to one particular example, the controller 86 may include a feedback control loop including a temperature sensor 350 and a proportional-integral (PI) control component.

The temperature adjustment of the shaving unit may be accomplished directly based on the temperature reading of the temperature sensor 350. Alternatively, the controller may be adapted to determine a corrected temperature of the light output surface using the output from the temperature sensor and a temperature correction function applied to the output from the temperature sensor, and to control the power level of the lighting element in dependence on the corrected temperature of the light output surface. Here, the corrected temperature may be, for example, an estimated temperature at the skin contact surface, which may be different from the direct temperature measured by the temperature sensor. For example, the correction temperature may be calculated using a temperature calculation function applied to the temperature output from the temperature sensor.

According to a set of further embodiments, a novel optical arrangement may be provided in the shaving unit 10 for modulating the visible light profile provided at the light output surface 36 by means of one or more visible light illuminating elements 64. The shaving unit 10 in this example may be the same as or similar to the shaving units described above in relation to the earlier embodiments. In particular, all features of any of the electric shaver 100 and the shaving unit 10 described above are compatible with this set of other embodiments of the invention, but some features may be omitted. As an example, a control scheme with an initial heating phase and an operating phase is not necessary.

By way of introduction to this set of further embodiments, it is noted that it is advantageous to include a visible light illuminating element 64 in the plurality of lighting elements 20, the main function of which is to provide a visible light source for providing a visual indicator to a user of activation of the heating function of the lighting module 14. The lighting element for heating produces a light output in the non-visible spectrum, meaning that no visual feedback is provided to the user. By integrating optical feedback in the visible domain at the location of the light output surface 36, the user is able to identify the operating state.

It is an object of at least one set of embodiments of the present invention to integrate light management elements into the shaving unit 10 to modify what would otherwise appear as separate point source light points at the light output surface 36. This is schematically illustrated by fig. 11, which fig. 11 shows an example visible light profile 65 generated by the visible light illuminating elements at the light output surface 36 without providing an optical arrangement in the lighting module. Fig. 12 shows a cross section through such a lighting module 14, in which there is no optical arrangement for guiding visible light. Forward visible light illuminating elements 64 are shown mounted on first (upper) major surface 42 of PCB 38. The light output surface 36 may be understood to include an adjacent area 420 that corresponds to an area of an imaginary projection 422 of the visible light illuminating element 64 onto the light output surface, as shown in fig. 12. This adjacent area 420 is relatively small for each individual illumination element, meaning that the visible light generated by each visible light illumination element 64 appears to the viewer 419 to be a point source on the light output surface 36. However, this does not represent the fact that the actual thermal treatment spreads across a wider surface area of the light output surface 36.

Thus, in accordance with one or more embodiments, the lighting module 14 is further provided with an optical arrangement for producing a visible light output at the light output surface 36 provided by the visible light illuminating element 64.

An example is schematically shown in fig. 13 to 15, which will now be described.

A shaving unit 10 is provided that includes an illumination module 14 having one or more Infrared (IR) or Near Infrared (NIR) illumination elements 62 and one or more visible light illumination elements 64 for producing visible light. Only one visible light illuminating element 64 is shown in fig. 13-15, but in further examples a plurality of such elements may be provided. Both the IR or NIR lighting element 62 and the visible lighting element 64 are arranged in optical communication with the light output surface 36. The visible light illuminating element 64 is configured and arranged to be activated in conjunction with activation of the IR or NIR illuminating element 62 for providing a visible indication of activation of the IR or NIR illuminating element 62. Activation of the IR or NIR lighting element 62 and the visible light lighting element 64 may be controlled, for example, by a controller.

As previously described, the light output surface 36 may be understood to include one or more adjacent regions 420, each adjacent region 420 including an area of an imaginary projection 422 of a respective one of the visible light illuminating elements 64 onto the light output surface 36. The optical arrangement comprises a light directing device 412 configured to direct visible light generated by the visible light illuminating element 64 at least to a primary area 424 of the light output surface, wherein the primary area does not comprise one or more adjacent areas 420 of the light output surface 36.

The optical arrangement further comprises one or more light attenuating elements 416, each disposed between a respective one of the visible light illuminating elements 64 and an adjacent region 420 of the light output surface 36 associated with the respective one of the visible light illuminating elements 64, and each having a transmittance for visible light that is less than the transmittance for visible light of the light directing device 412. In the examples shown in fig. 13-15, the one or more light attenuating elements 416 each include a layer of light attenuating material 450, which may be partially light attenuating (i.e., translucent) or fully light attenuating (i.e., opaque). In the example shown, the light attenuating material layer 450 is deposited on a portion of an otherwise light transmissive (e.g., optically transparent) carrier sheet 472, the carrier sheet 472 extending atop the light directing member 440 and the visible light illuminating element 64. In other examples, each light attenuating element 416 may be formed from an integral part of the carrier sheet 472, for example as a light attenuating (e.g., colored) portion of an additional optically transparent sheet.

The carrier sheet 472 may be optically transparent. However, in other examples, the carrier sheet may be light transmissive and at the same time optically diffusive or scattering in order to promote a more uniform distribution of light across the primary region 424 of the light output surface.

Fig. 14 schematically shows a modified visible light profile provided to the light output surface as a result of the light directing arrangement 412. The light-attenuating elements 416 inhibit a direct light path from each visible light illuminating element 64 to the light output surface 36, i.e., to a proximal region 420 of the light output surface 36 associated with the visible light illuminating element 64.

In the example of fig. 13 to 15, the light guiding means 412 comprises a light guiding member 440, which light guiding member 440 is arranged to guide the visible light generated by the visible light illuminating element 64 in a guiding direction having a main directional component parallel to the light output surface 36. The one or more visible light illuminating elements 64 may each comprise, for example, a side-looking LED arranged to introduce visible light into the light guiding member 440 via the edge surface 442 of the light guiding member 440.

The light guiding member 440 may comprise a light out-coupling element configured for coupling visible light out of the light guiding member 440 in a direction towards the light output surface 36. For example, the light directing member may include an array of inclined light directing surfaces for reflecting or scattering light (not shown in fig. 13-16, but visible in fig. 17, for example) outwardly from the light directing member.

Fig. 15 shows a closer cross-sectional view of the PCB38 arrangement of the embodiment of fig. 14.

Fig. 16 shows a view of the skin contact surface 54 of the shaving unit 10, in this case the skin contact surface 54 being formed by the upper wall 34 of the housing 18 of the lighting module 14. Fig. 16 shows a light output surface 36 which may form at least part of the skin contact surface 54. Fig. 16 shows the spatially extended visible light output achieved by the optical arrangements discussed above and shown in fig. 13-15. As shown, this corresponds to the primary region 424 of the light output surface shown in fig. 14, to which region 424 the visible light of the visible light illuminating element 64 is directed by the light directing means 412 of the lighting module 14.

The spatial position of the particular visible light illuminating element 64 shown in fig. 13-15 is shown in fig. 16.

Fig. 17 shows a perspective view of the PCB38, the lighting elements and the optical arrangement of the lighting module of fig. 13-15. The visible light illuminating element 64 is mounted on the first major surface 42 of the PCB, which when assembled faces the light output surface 36 (not shown in fig. 17). The visible light illuminating elements 64 are not directly visible in fig. 17 because they are mounted underneath the corresponding layers of opaque material 450, hiding them from view.

In the example shown, each visible light illuminating element 64 is a side-emitting visible light illuminating element. The light directing means 412 is shown in figure 17. The light guiding means comprises a light guiding member in the form of a light guiding sheet 460, the light guiding sheet 460 being arranged on the first main surface 42 of the PCB. Each light attenuating material layer 450 forms a light attenuating element. The layer of light attenuating material is provided by disposing an optically transparent carrier sheet 472 over the light guiding sheet 460, wherein each light attenuating element is provided as an opaque ink layer on a respective area of the optically transparent carrier sheet 472 that is located in a direct light path between a respective one of the visible light illuminating elements 64 and the light output surface, e.g., on an area directly above each respective visible light illuminating element 64.

Although in this example, the light attenuating material layer 450 is provided in the form of an opaque ink layer, other options are possible. Instead of an opaque ink layer, a mask layer may be provided which partially attenuates light. These may be facilitated by partial light attenuation of the ink or by different materials. They may be facilitated by an adhesive layer (e.g., sticker) that adheres to the relevant portion of the carrier sheet 472, which in some examples may have a color such as red.

Further, as described above, while in the illustrated example the carrier sheet 472 is optically transparent, in other examples the carrier sheet may be a light-transmissive light diffusing sheet to improve the uniformity of the visible light profile provided at the light output surface.

In the example of fig. 13-17, the light guiding member is a light guiding sheet 460 that is optically configured to provide a light scattering or diffusing effect in order to spread the visible light output from the visible light illuminating elements 64 across a wider visible area of the light output surface 36 of the lighting module 14. The visible light illuminating element 64 may be a side visible light illuminating element, wherein the light guiding sheet 460 receives and guides the visible light generated by the visible light illuminating element 64 in a guiding direction having a main directional component parallel to the light output surface 36 of the lighting module 14. The visible light illuminating element 64 may, for example, be received within a cavity or opening or recess formed in a side wall 444 of the light guiding member, and wherein light from the visible light illuminating element 64 is introduced into the light guiding member 440 via an edge surface 442 within the cavity within the light guiding member 440.

The light guiding sheet 460 comprises a light out-coupling element 462, the light out-coupling element 462 being configured for coupling visible light out of the light guiding member in a direction towards the light output surface. In the example of fig. 17, the light guiding sheet 460 is configured to comprise in particular a linear array of slanted planar faces (planar faces) 462 for scattering and outcoupling light from the light guiding sheet 460 in the direction of the light output surface 36 above the PCB 38.

The visible light illuminating element 64 is disposed on the same PCB38 as the IR or NIR illuminating element 62.

Fig. 18 shows an exploded view of the example lighting module 14 of fig. 13-17. The light output surface 36 of the illumination module housing 18 forms a skin contact surface of the shaving unit. Within the lighting module housing 18 is received a layered stack comprising: a PCB38 carrying IR/NIR lighting elements 62 and visible light lighting elements 64 mounted to its first major surface 42, a light guiding sheet 460 mounted on the first major surface 42 of the PCB38 (e.g., by an adhesive), and an optically transparent carrier sheet 472 having opaque ink layers 470 deposited thereon, each of which forms a light attenuating element 416. As previously mentioned, the layered stack is encapsulated within the lighting module housing 18 by the potting material 40. Fig. 18 also shows electrical connection pins 23 provided on the second major surface 44 of the PCB38 for connecting the lighting elements 62, 64 to a power supply in the shaver body. Fig. 18 does not show the layer of potting material disposed at the second major surface 44 of the PCB 38.

In the example of fig. 17, both the visible light illuminating element 64 and the IR or NIR illuminating element 62 are mounted on the first major surface 42 of the PCB38 facing the light output surface 36. However, in an alternative set of embodiments, the IR or NIR lighting element 62 may be mounted on the first major surface 42, and the visible light lighting element 64 may be mounted on the second major surface 44 of the PCB opposite the first major surface 42, or on both the first and second major surfaces 42, 44 of the PCB 38. In this example, portions of the PCB38 itself serve as the light attenuating element 416 of the visible light illuminating element 64 mounted on the second major surface 44 of the PCB38, thereby suppressing a direct light path between the visible light illuminating element 64 on the second major surface 44 and the light output surface 36.

An example is schematically shown in fig. 19. Visible light illuminating element 64 is mounted on second major surface 44 of PCB 38. The aforementioned one or more light attenuating elements may be understood as each being formed by a respective portion of the PCB38 on which a respective one of the visible light illuminating elements 64 is disposed.

In this case, the light guiding means 412 comprises a light guiding and/or light reflecting portion 480 of the housing 18 of the lighting module 14. In this case, the lighting module housing 18 itself thus forms at least part of the light guiding means. As shown in fig. 19, an inner surface 480 of the lighting module housing 18 may be arranged to direct and/or reflect visible light generated by the visible light illuminating elements 64 on the second major surface 44 of the PCB38 towards the light output surface 36. Furthermore, the housing 18 of the lighting module 14 may be integrally made of the same light transmissive material forming the light output surface 36, and the upper wall 34 of the housing 18 and the side walls 50 of the housing 18 may comprise light guiding and/or reflecting portions of the housing 18 of the lighting module 14. In other words, the body of the lighting module housing 18 may be adapted to receive visible light emitted by the visible light illuminating elements 64 on the second major surface 44 of the PCB38 and to couple the visible light to the light output surface 36. In some examples, the body of the lighting module housing 18 is adapted to impart a scattering effect to the visible light, thereby diffusing the visible light through the body of the lighting module housing 18. This is known as volume scattering and has the effect of providing diffuse visible light illumination of the entire upper wall 34 of the lighting module housing 18, as shown, for example, in fig. 20.

In some examples, the light guiding and/or light reflecting portion 480 of the housing 18 of the lighting module 14 is arranged to cooperate with further light guiding and/or light reflecting portions of the hair cutting unit 12 and/or the support member 22 (see fig. 1-3) for guiding and/or reflecting visible light generated by the visible light illuminating element 64 on the second main surface 44 of the PCB38 towards the light output surface 36.

For example, the visible light reflecting element or reflecting surface/interface may be formed in the body of the lighting module housing 18 and/or the body of the support member 22. The reflective surface may be configured to provide a Total Internal Reflection (TIR) effect. A reflecting and/or scattering element may be provided in or around the one or more hair cutting units 12, which reflecting and/or scattering element is arranged to receive at least a part of the visible light output of the visible light illuminating element 64.

Although in the example of fig. 19, the visible light illuminating elements 64 are mounted on the second major surface 44 of the PCB38, the lighting module housing 18 formed of a light transmissive material using volumetric scattering for visible light is also compatible with the visible light illuminating elements mounted on the first major surface 42 of the PCB.

Fig. 21 shows another perspective view of the first (upper) and second (lower) major surfaces 42, 44 of the PCB38 of the example shown in fig. 13-18.

The PCB38 includes a central region 502 with a plurality (in this case three) elongate arms 504a,504b,504c extending outwardly from the central region 502, each arm of the PCB38 having a smaller width stem portion connected to the central region and a wider width end portion. Each wider width end carries one or more IR or NIR lighting elements and at least one visible lighting element. These may be referred to as a first peripheral group 520a, a second peripheral group 520b and a third peripheral group 520c of lighting elements. The central region also carries one or more IR or NIR lighting elements and at least one visible lighting element, and these lighting elements may be collectively referred to as a central group of lighting elements 510. At least one temperature sensor may be disposed on the PCB. The stem portion of the arm of the PCB may be free of electrical components. When assembled, they may carry a light guiding member 440, such as a light guiding sheet 460.

When assembled, and as schematically shown in fig. 22, a central group 510 of lighting elements may be arranged in a central area of the shaving unit 10, between the first, second and third hair cutting units 12a, 12b, 12c, and may comprise a central IR or NIR lighting element 512 and at least three central visible light lighting elements 516. And each includes a peripheral IR or NIR lighting element 522 and at least one peripheral visible lighting element 524.

Fig. 23 shows a view of a light guiding member 440 in the form of a light guiding sheet 460 previously shown in fig. 13-18, for mounting on the PCB38 of fig. 21. The light directing member 440 has a multi-arm geometry that corresponds to the geometry of the PCB 38. It comprises in particular a first portion 530, a second portion 532 and a third portion 534. When assembled, the first portion extends between a first one of the central visible light illuminating elements 516 and at least one peripheral visible light illuminating element 524 of the first peripheral set 520a of light illuminating elements. Second portion 532 extends between a second one of central visible light illuminating elements 516 and at least one peripheral visible light illuminating element 524 of second peripheral group 520b of light illuminating elements. Third portion 534 extends between a third visible light illuminating element of central visible light illuminating element 516 and at least one peripheral visible light illuminating element 524 of a third peripheral set 520c of light illuminating elements. The lighting module further comprises light attenuating elements for the central visible light illuminating element 516 and for the peripheral visible light illuminating elements 524 (not shown in fig. 21-23) which are provided in a similar manner as previously explained in connection with the embodiments of fig. 12-18.

As described above, embodiments utilize a controller. The controller may be implemented in software and/or hardware in a variety of ways to perform the various functions required. A processor is one example of a controller that employs one or more microprocessors that are programmable using software (e.g., microcode) to perform the required functions. However, the controller may be implemented with or without a processor, and may also be implemented as a combination of dedicated hardware to perform certain functions and a processor (e.g., one or more programmed microprocessors and associated circuitry) to perform other functions.

Examples of controller components that may be employed in various embodiments of the present invention include, but are not limited to, conventional microprocessors, application Specific Integrated Circuits (ASICs), and Field Programmable Gate Arrays (FPGAs).

In various implementations, a processor or controller may be associated with one or more storage media such as volatile and non-volatile computer memory (such as RAM, PROM, EPROM, and EEPROM). The storage medium may be encoded with one or more programs that, when executed on one or more processors and/or controllers, perform the desired functions. Various storage media may be fixed within a processor or controller or may be transportable such that the program or programs stored thereon can be loaded into a processor or controller.

Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing 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.

A single processor or other unit may fulfill the functions of several items recited in the claims.

The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the internet or other wired or wireless telecommunication systems.

If the term "adapted" is used in the claims or the description, it is to be noted that the term "adapted" is intended to be equivalent to the term "configured to".

Any reference signs in the claims shall not be construed as limiting the scope.

Reference numerals

Shaving unit (10)

Electric razor (100)

Hair cutting unit (12)

Lighting module (14)

Lighting module casing (18)

Lighting element (20)

Strutting piece (22)

Contact pin (23)

Cavity (32)

Lighting module upper wall (34)

Light output surface (36)

PCB(38)

Encapsulating material (40)

Encapsulating material layer (41 a)

The other layer of encapsulating material (41 b)

PCB first main surface (42)

PCB second main surface (44)

PCB edge surface (46)

Casing side wall (50)

Skin contact surface (54)

Opening (56)

IR or NIR lighting element (62)

Visible light lighting element (64)

The inner surface of the upper wall (72)

Shaver main body (110)

External cutting component (120)

Hair entrance opening (122)

Controller (86)

Initial heating stage (310)

Operating phase (320)

PI controlling parts (334)

Temperature sensor (350)

Light guide device (412)

Light attenuating element (416)

Output surface vicinity (420)

Imaginary projection (422)

Output surface main area (424)

Light guide member (440)

Layer of light attenuating material (450)

Light guide sheet (460)

Opaque ink layer (ink layer) (470)

Optically transparent carrier sheet (472)

Light guiding/reflecting part (480)

Central lighting element group (510)

Central IR or NIR lighting element (512)

Central visible light illuminating element (516)

First peripheral group (520 a)

Second peripheral group (520 b)

Third peripheral group (520 c)

Peripheral IR/NIR lighting elements (522)

Visible light illuminating component of periphery (524)

Light directing member first portion (530)

Light directing member second part (532)

Light guide member third part (534)

Claims (17)

1. A shaving unit (10) for an electric shaver (100), comprising:

one or more hair cutting units (12);

a lighting module (14) comprising a lighting module housing (18) accommodating one or more lighting elements (20); and

a support member (22) supporting the one or more hair cutting units and the lighting module;

wherein the lighting module housing has a cavity (32), wherein the lighting element is arranged in the cavity, and wherein the cavity is covered by an upper wall (34) of the lighting module housing on a skin-facing side of the lighting module housing;

wherein the upper wall of the lighting module housing is made of a light-transmissive material and comprises a skin-facing light output surface (36) via which light generated by the lighting element is exposed to the skin during operation of the shaving unit, the light output surface being arranged for contacting the skin during operation of the shaving unit;

wherein the lighting module comprises a PCB (38) arranged in the cavity, and wherein the lighting element is mounted to a first major surface (42) of the PCB facing the upper wall of the lighting module housing such that the lighting element is in optical communication with the light output surface during operation of the shaving unit;

wherein the cavity (32) comprises a light transmissive potting material (40) covering the first major surface (42) of the PCB encapsulating the lighting element and extending between the first major surface of the PCB and the upper wall (34) of the lighting module housing (18), and wherein the potting material (40) also covers a second major surface (44) of the PCB opposite the first major surface, such that the potting material encapsulates the PCB on all major sides.

2. The shaving unit (10) of claim 1 wherein the potting material (40) extends uninterrupted from the first major surface (42) of the PCB (38) to the upper wall (34) of the lighting module housing (18).

3. The shaving unit (10) according to claim 1 or 2, wherein the potting material (40) at least partially covers an edge surface (46) of the PCB (38), the edge surface (46) extending between the first main surface (42) and the second main surface (44).

4. The shaving unit (10) according to any one of the preceding claims wherein the lighting module housing (18) comprises a side wall (50), the side wall (50) defining the cavity (32) in combination with the upper wall (34) of the lighting module housing.

5. The shaving unit (10) according to any one of the preceding claims, wherein the one or more lighting elements (20) each comprise an LED.

6. The shaving unit (10) according to any one of the preceding claims, wherein the one or more lighting elements (20) comprise Infrared (IR) or Near Infrared (NIR) lighting elements (62).

7. The shaving unit (10) according to claim 6, wherein the light transmissive material and/or the potting material (40) has a light transmittance peak with a light wavelength in the range of 800-1050 nm.

8. The shaving unit (10) of claim 5, wherein the one or more LEDs are each configured to emit light having a wavelength primarily in the range of 525nm-575nm,675nm-725nm, or 775nm-825 nm.

9. The shaving unit (10) according to any one of the preceding claims, wherein the lighting module housing (18) is made entirely of the light-transmissive material.

10. The shaving unit (10) according to claim 9, wherein the lighting module housing (18) is a one-piece injection molded polymer structure.

11. The shaving unit (10) according to any one of the preceding claims, wherein the lighting module housing (18) comprises a skin contact surface (54), the skin contact surface (54) being arranged to be in contact with the skin during operation of the shaving unit, wherein the skin contact surface defines one or more openings (56), a respective one of the one or more hair cutting units (12) being provided within the one or more openings (56) such that the one or more hair cutting units are each completely surrounded by the skin contact surface, and wherein the light output surface (36) is part of the skin contact surface.

12. The shaving unit (10) according to claim 11, wherein the shaving unit comprises at least two hair cutting units (12), and wherein the light output surface (36) of the illumination module (14) extends at least in the area of the skin contact surface (54) between the hair cutting units (12).

13. The shaving unit (10) according to any one of the preceding claims, wherein the potting material (40) comprises a glue resin, such as silicon or an epoxy resin.

14. The shaving unit (10) according to any one of the preceding claims, wherein the potting material (40) comprises a light transmissive base potting material and ceramic particles embedded in the base potting material, the ceramic particles having a size smaller than a wavelength of light emitted by the one or more lighting elements of the lighting module.

15. The shaving unit (10) according to any one of the preceding claims, wherein the lighting module (14) comprises one or more electrical connection members electrically connected to the PCB (38) and extending from the second major surface (44) of the PCB through the potting material (40) and out of the potting material (40).

16. An electric shaver (100), comprising:

the shaving unit (10) according to any one of the preceding claims; and

a body (110) coupled to the shaving unit for driving the one or more hair cutting units;

wherein the one or more hair cutting units of the shaving unit each comprise:

an external cutting member (120) having a plurality of hair entry openings (122); and

an internal cutting member having a plurality of cutting elements, the internal cutting member being covered by the external cutting member and being movable relative to the external cutting member.

17. A method (200) of providing a shaving unit for an electric shaver, the method comprising the step of providing a lighting module (14), the step comprising:

providing (210) a lighting module housing (18), the lighting module housing (18) comprising an upper wall (34) and a side wall (50), the upper wall (34) comprising a light output surface (36), the side wall (50) in combination with the upper wall defining a cavity (32) of the lighting module housing, wherein the upper wall has an inner surface (72) facing the cavity;

providing a lighting unit comprising a PCB (38) and one or more lighting elements (20) mounted to a first major surface (42) of the PCB,

-providing (230) a layer (41 a) of light-transmissive potting material (40) on the inner surface (72) of the upper wall (34);

placing (240) the lighting unit onto the layer of potting material in the cavity with the first major surface (42) of the PCB facing the upper wall such that the first major surface of the PCB is wetted by the potting material and the lighting elements are each encapsulated by the potting material;

providing (250) a further layer (41 b) of the potting material (40) over the lighting unit to cover a second major surface (44) of the PCB (38) opposite the first major surface (42), whereby the lighting unit is fully encapsulated by the potting material;

disposing the potting material;

wherein the method further comprises the step of including the lighting module (14) as part of the shaving unit such that the light output surface (36) is in contact with the skin of a user when the shaving unit is applied to the skin for shaving during operation of the shaving unit.

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