Shaving unit and electric shaver equipped therewith

Abstract

A shaving unit and / or electric shaver having an illumination module for providing light heating functionality to a skin-contacting surface of the shaving unit. At least one aspect of the invention relates to a sealing arrangement for components of the illumination module by means of a potting material that seals, both above and below, a holder on which the illumination elements are mounted.

Description

[Technical Field]

[0001] The present invention relates to a shaving unit for an electric shaver, and an electric shaver equipped with this shaving unit. [Background technology]

[0002] The present invention belongs to the field of shavers, particularly electric shavers designed to perform shaving operations in which hair is cut close to the skin. Generally, an electric shaver comprises a shaving unit in which one or more hair cutting units are arranged, and the shaving unit comprises a base member for supporting one or more hair cutting units. A particularly common design of the shaving unit uses three hair cutting units arranged in an equilateral triangle. In addition to the shaving unit, the electric shaver comprises a body. The body is usually shaped to be suitable for the user of the shaver to grip and houses various components of the shaver, such as an electric motor.

[0003] Each hair cutting unit of a shaving unit comprises a combination of an internal cutting member and an external cutting member positioned to cover the internal cutting member, the external cutting member having a series of hair entry openings to allow hair to pass through the external cutting member and reach and strike the internal cutting member during the shaving motion. In practical designs, the external cutting member is generally cup-shaped with a substantially circular periphery, and the hair entry openings are elongated slit-like in shape, extending substantially radially with respect to the central axis of the external cutting member within one or more annular regions that constitute one or more hair cutting trajectories. Such external cutting members are particularly suitable for use in rotary electric shavers, i.e., electric shavers that include at least one hair cutting unit in which an internal cutting member inside is configured to rotate during operation.

[0004] Proper use of an electric shaver requires that the shaver be put into operation, i.e., that the internal cutting member of at least one hair cutting unit is rotated, and that the shaving unit be moved over the portion of skin to be shaved. The external cutting member has a hair cutting trajectory surface that contacts a portion of the skin at one or more hair cutting trajectory positions during the hair cutting operation. A hair cutting surface is present within the external cutting member at the position where the hair entry opening is defined. In a typical design, the internal cutting member includes a blade with a hair cutting blade. During the shaving operation, hairs entering the hair entry opening are subjected to shear force between the hair cutting surface and the hair cutting blade, resulting in them being cut close to the skin.

[0005] Chinese Patent Publication No. 108714917A discloses an electric shaver comprising a shaving unit and a main body. This shaver includes an infrared heating device, a battery, and a switch that are electrically connected to each other. The reason for equipping an electric shaver with an infrared (or near-infrared) heating device, as known from Chinese Patent Publication No. 108714917A, is that exposing hair to infrared light helps to soften the hair. In general, when hair is exposed to infrared light during the shaving process, the comfort felt by the user is improved. In addition, infrared light has beneficial effects on the skin by promoting blood circulation and stimulating the skin, resulting in a brighter appearance.

[0006] In addition to infrared light, other light emissions, including those within the visible light spectrum, can also be used to generate heating stimuli. [Overview of the project] [Problems that the invention aims to solve]

[0007] In conventional electric shavers, all electrically operated components are housed within the main body, which has a waterproof casing that encloses all internal components. However, including a lighting module within the shaver head means that the electrically operated components are located outside the main body casing. This raises concerns about the reliability of the shaver head over the long term. It is considered worthwhile to improve existing designs to address this problem. [Means for solving the problem]

[0008] The present invention is defined by the claims.

[0009] According to one aspect of the present invention, a shaving unit for an electric shaver is provided. The shaving unit comprises one or more hair cutting units, a lighting module having a lighting module housing housing one or more lighting elements, and a support member supporting one or more hair cutting units and the lighting module. The lighting module housing has a cavity, the lighting elements are arranged within the cavity, the cavity is on the skin-facing side of the lighting module housing and is covered by the upper wall of the lighting module housing. The upper wall of the lighting module housing is preferably made of an optically transparent material and has a skin-facing light-emitting surface, and during the operation of the shaving unit, light generated by the lighting elements is exposed to the skin through the skin-facing light-emitting surface. The light-emitting surface is positioned to contact the skin during the operation of the shaving unit.

[0010] The lighting module comprises a PCB located within a cavity, and the lighting elements are mounted on a first main surface of the PCB facing the upper wall of the lighting module housing so that the lighting elements are optically connected to the light-emitting surface during the operation of the shaving unit.

[0011] The cavity seals the lighting element by covering the first main surface of the PCB and includes an optically transparent potting material extending between the first main surface of the PCB and the upper wall of the lighting module housing. The potting material further covers the second main surface of the PCB on the opposite side of the first main surface. The potting material thus seals the PCB on all main sides.

[0012] The shaving unit forms a shaving head for a shaver device, which is adapted to be attached to a shaver body having a motor, for example, as will be described in more detail later.

[0013] The lighting module of the shaving unit according to the present invention can provide a heating effect to the skin during the shaving process. The heating effect is achieved by light and conduction. Heating of the skin by light is achieved by the absorption of light by the skin tissue of light generated by the lighting element and applied to the skin through the light-emitting surface of the lighting module. Heating of the skin by conduction is achieved by the thermal contact of the skin with the light-emitting surface of the lighting module, which is in thermally conductive contact with the lighting element via the potting material and the upper wall of the lighting module housing. In this case, heating of the skin by conduction is particularly achieved by heat that will be dissipated from the lighting element due to the limited efficiency of electrical-light energy conversion. This combined heating of the skin by light and conduction is very effective.

[0014] By completely sealing the lighting element with potting material, the potting material protects the lighting element from moisture intrusion. Furthermore, by extending the potting material from the lighting element to the light-emitting surface (which also forms the skin contact surface), the potting material provides a secondary function of mediating heat conduction from the lighting element to the light-emitting surface in contact with the skin, thereby improving the efficiency of skin heating. 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 it. Moreover, by promoting conductive heat transfer using the same potting material that achieves fluid isolation of the lighting element, structural efficiency is achieved by the proposed configuration.

[0015] It is advantageous if the potting material is provided such that it extends continuously from the first main surface of the PCB to the upper wall of the lighting module housing. In this way, a seamless, solid thermal path is defined between the PCB and the upper wall, supporting conductive heat transfer to the surface.

[0016] It is advantageous that the potting material is provided such that it also at least partially covers the edge surface of the PCB, and that this edge surface extends between the first main surface and the second main surface (connecting them). This ensures that the PCB is completely surrounded by the potting material, further reducing the possibility of moisture penetration.

[0017] Referring to the lighting module housing, it includes side walls that, in combination with the upper wall of the lighting module housing, define the cavity.

[0018] Referring to the lighting elements, they all feature LEDs.

[0019] In a set of advantageous embodiments, one or more lighting elements each comprise an infrared (IR) or near-infrared (NIR) lighting element. IR and NIR have a deep tissue penetration depth and effective heating characteristics. One or more lighting elements each comprise an LED configured to emit light having a wavelength mainly within the range of 915 - 965 nm. However, lighting elements within the visible light spectrum are also contemplated, particularly those at the low-frequency red end of the visible light spectrum.

[0020] In some embodiments, the optically transmissive material and / or potting material (included in the upper wall of the lighting module housing) is provided with at least one light transmittance peak within the optical wavelength range of 800 - 1050 nm. This is used in combination with the provision of lighting elements adapted to generate light emission within the corresponding wavelength band. In this exemplary case, this means lighting elements adapted to generate light emission at the high-frequency side end of the infrared range, particularly the infrared range that abuts / overlaps with the red end of the visible light spectrum.

[0021] In some embodiments, one or more lighting elements of the lighting module each comprise an LED, and one or more LEDs are each configured to emit light having a wavelength mainly within the range of 525 - 575 nm, within the range of 675 - 725 nm, or within the range of 775 - 825 nm. In relation to each wavelength range described herein, the term "mainly" means that at least 80%, preferably at least 90%, more preferably at least 95% of the light power of each LED is supplied by wavelength components within the corresponding wavelength range. Optical-thermal simulations were performed taking into account the wavelength-dependent optical properties of the epidermis and dermis of human skin and the wavelength-dependent electro-optical energy conversion efficiency of the LEDs. These simulations showed that the power required when using LEDs that mainly emit light within one of the three wavelength ranges already described herein to achieve a predetermined thermal depth profile in human skin within a predetermined time is significantly lower than when using LEDs that mainly emit light within the IR or NIR wavelength range.

[0022] In some embodiments, the entire lighting module housing is made of an optically transmissive material. This has the advantage that the walls of the housing itself contribute to coupling the light emission of the lighting element to the light emission surface. The optically transmissive material is sometimes translucent rather than transparent so as to help hide the interior of the housing from the direct view of the user when looking at the light emission surface. In some examples, the lighting module further comprises a visible light illumination element, and the housing serves to couple visible light to the light emission surface.

[0023] In some embodiments, the lighting module housing is an integrally molded injection molded polymer structure.

[0024] In one advantageous configuration, the lighting module housing comprises a skin contact surface arranged to contact the user's skin during operation of the shaving unit, the skin contact surface defining one or more openings in which one of each of the one or more hair cutting units (mentioned above) is disposed such that each of the one or more hair cutting units is completely surrounded by the skin contact surface. The light emission surface mentioned above is in this example part of the skin contact surface of the lighting module housing. This may actually form the entire skin contact surface or only a part thereof, such as a light emission window provided within the skin contact surface.

[0025] In some examples, the shaving unit comprises at least two hair cutting units, and the light emission surface of the lighting module extends at least within the region between the hair cutting units of the skin contact surface. In this way, the heating effect from the lighting module is conducted and radiated to regions of the skin contact surface that respectively precede or follow the two hair cutting units when the user slides the shaver unit along their skin during normal use. Thus, a warming effect is provided to the area of the skin that the shaving unit actively engages.

[0026] When referring to potting materials, this includes, in some examples, adhesive resins, such as silicone resins or epoxy resins.

[0027] In some examples, the potting material comprises an optically transparent base potting material and ceramic particles embedded in the base potting material, wherein the ceramic particles are smaller in size than the wavelength of light emitted by one or more illuminating elements of the lighting module. The base potting material comprises a resin, such as a silicone resin or epoxy resin, a silicone curing gel, or another epoxy mixture. Examples of suitable ceramic particle materials include TiO2, Al2O3, BeO, AlN, and SiC. The ceramic particles embedded in the base potting material improve heat transfer from the illuminating elements through the potting material to the light-emitting surface of the lighting module that comes into contact with the skin during the operation of the shaving unit. At the same time, the ceramic particles improve the dispersion of light generated by the illuminating elements across the light-emitting surface of the lighting module via light scattering. As a result, heat transfer losses are reduced, and thermal hot spots on the light-emitting surface caused by uneven dispersion of light are largely prevented. Because the size of the ceramic particles is smaller than the wavelength of light emitted by the illuminating elements, most of the light scattering caused by the ceramic particles is forward scattering.

[0028] Regarding the electrical configuration of the lighting module, the lighting module comprises one or more electrical connection members that are electrically connected to the PCB and extend outward from the second main surface (opposite side) of the PCB through the potting material. These electrical connections thus extend outward from the back of the lighting module (i.e., away from the direction of the light-emitting surface).

[0029] Referring to one or more hair cutting units, each comprises an external cutting member having a plurality of hair entry openings, and an internal cutting member covered by the external cutting member and having a plurality of cutting elements movable relative to the external cutting member.

[0030] Another aspect of the present invention provides an electric shaver comprising a shaving unit relating to any of the embodiments described above (or further described later in this disclosure). The electric shaver further comprises a shaver body for driving one or more hair cutting units, which are coupled (e.g., detachably) to the shaving unit.

[0031] The shaver body includes an electric motor for driving the cutting unit of the shaving unit.

[0032] Another aspect of the present invention is a method for providing a shaving unit for an electric shaver. The method comprises a sub-step of providing a lighting module, which sub-step is A step of providing a lighting module housing comprising an upper wall having a light-emitting surface, and side walls that, in combination with the upper wall, define a cavity of the lighting module housing, wherein the upper wall has an inner surface facing into the cavity, A step of providing a lighting unit comprising one or more lighting elements mounted on a PCB and a first main surface of a PCB, The steps include: placing a layer of optically transparent potting material on the inner surface of the upper wall; The first main surface of the PCB is coated with potting material, and the lighting unit is placed on the layer of potting material in the cavity, with the first main surface of the PCB facing the upper wall, such that all lighting elements are sealed by the potting material. The steps include providing an additional layer of potting material on the lighting unit so as to cover the second main surface of the PCB opposite the first main surface, and the lighting unit being completely sealed by the potting material, and The process includes a step of hardening the potting material.

[0033] The method further includes the step of including an illumination module as part of the shaving unit such that, during the operation of the shaving unit, the light-emitting surface comes into contact with the skin when the shaving unit is placed against the user's skin to perform shaving. This step may be performed at any stage of the manufacturing method. This step can be achieved essentially, at least in part, through the execution of the above step of forming the illumination module, for example, if the illumination module housing is provided integrated with a support structure (e.g., coupled to the support member mentioned above) that will combine with the illumination module to form the shaving unit. Alternatively, this step may be a separate step performed after the construction of the illumination module, in which case the illumination module is inserted into or integrated with the shaving unit structure, for example, by mechanically coupling it with other components of the shaver unit.

[0034] These and other aspects of the present invention will become apparent from and be described with reference to the embodiments described below.

[0035] To better understand the present invention and to more clearly illustrate how it can be realized, the following attached drawings are referenced hereby merely as examples. [Brief explanation of the drawing]

[0036] [Figure 1] This is a perspective view of the external appearance of an exemplary electric shaver according to one or more embodiments of the present invention. [Figure 2] This is a cutaway perspective view of a shaving unit according to one aspect of the present invention. [Figure 3] This is a cross-sectional view through the lighting module of a shaving unit according to one or more embodiments of the present invention. [Figure 4] This is a partially cutaway view of the interior of a lighting module housing according to one or more embodiments of the present invention. [Figure 5]This is a further cross-sectional view through a lighting module according to one or more embodiments of the present invention. [Figure 6] This figure shows the steps of an example of an exemplary method for manufacturing a lighting module according to one or more embodiments of the present invention. [Figure 7] This figure shows the first and second operational stages of an illustrative lighting module according to one aspect of the present invention. [Figure 8] This figure shows the skin temperature profiles corresponding to the subjects' discomfort and injury. [Figure 9] This figure shows an exemplary light emission profile resulting from an exemplary spatial arrangement of lighting elements within a lighting module, according to at least one embodiment of the present invention. [Figure 10] This figure shows an example drive circuit for controlling a lighting module using sensor feedback from a temperature sensor. [Figure 11] This figure shows undesirable visible light emission from a lighting module in an electric shaver, provided when there is no optical device to correct the visible light profile. [Figure 12] This figure shows an example illumination module in an electric shaver when there is no optical device to correct the visible light profile. [Figure 13] This is a cross-sectional view of an exemplary lighting module within a shaving unit according to the present invention, which has an optical device for realizing visible light emission. [Figure 14] This is a cross-sectional view of an exemplary lighting module within a shaving unit according to the present invention, which has an optical device for realizing visible light emission guidance. [Figure 15] This is a cross-sectional view of an exemplary lighting module within a shaving unit according to the present invention, which has an optical device for realizing visible light emission guidance. [Figure 16] This figure shows a modified visible light profile provided on the light-emitting surface of a lighting module according to one or more embodiments of the present invention. [Figure 17]This is a perspective view of a part of the optical device in a lighting module according to one or more embodiments of the present invention. [Figure 18] This is an exploded view of an example of a shaving unit equipped with an optical device according to the present invention. [Figure 19] This figure shows a further embodiment of a lighting module having an optical device integrally formed by a housing of the lighting module. [Figure 20] This figure shows an example of visible light emission provided by the lighting module in Figure 19. [Figure 21] This figure shows the PCB portion of an exemplary lighting module according to the present invention. [Figure 22] Figure 21 shows the positional relationship between the lighting elements of the lighting module and the light-emitting surface of the lighting module. [Figure 23] This figure shows an example of a light guide member in a lighting module (Figure 21). [Modes for carrying out the invention]

[0037] The present invention will be described with reference to these figures.

[0038] The detailed descriptions and specific examples illustrate exemplary embodiments of the apparatus, system, and method, but it should be understood that they are for illustrative purposes only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, system, and method of the present invention will be better understood from the following description, the accompanying claims, and the accompanying drawings. It should be understood that these figures are schematic and not drawn to exact scale. It should also be understood that the same reference numerals are used throughout these figures to indicate the same or similar parts.

[0039] This disclosure generally relates to a shaving unit and / or electric shaver having a lighting module for providing a photoheating function to the skin contact surface of the shaving unit. At least one aspect of the present invention relates to a sealing component for a lighting module component, comprising a potting material that seals both the upper and lower sides of a holder on which a lighting element is mounted.

[0040] Figure 1 shows a first perspective view of the visible appearance 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 rotary (though not required) and comprises a body 110 intended to be held by the user of the shaver 100 and a shaving unit 10 intended to come into contact with the portion of skin to be shaved. The body 110 of the shaver 100 is also commonly called the handle, and the shaving unit 10 of the shaver 100 is also commonly called the shaving head. For various reasons, such as the need for maintenance and / or cleaning of the shaving unit 10, or the need to replace the shaving unit 10 with another type of functional unit, it is practical for the shaving unit 10 to be detachably or hinged to the body 110. The shaving unit 10 includes several hair cutting units 12, the number of which is three in the illustrated example. In the illustrated example, the hair cutting units 12 are arranged to form a roughly triangular shape. When the electric shaver 100 is applied for the purpose of performing a shaving action on a portion of the skin, the actual process of cutting the hairs protruding from that portion of the skin is performed at the location of the hair cutting unit 12. For the purpose of supporting the hair cutting unit 12, the shaving unit 10 includes a support member 22, which in this example functions as a base member for the shaving unit 10.

[0041] Each of the hair cutting units 12 comprises a combination of an external cutting member 120, which has a generally cup-shaped design, and an internal cutting member (not shown) having at least one hair cutting element and at least a portion of which is housed inside the internal cutting member. The external cutting member 120 has a hair entry opening 122 on its annular cutting trajectory surface. During the shaving operation, hairs extending through the hair entry opening 122 and protruding into the interior of the external cutting member 120 are cut when they come into contact with the hair cutting element of the internal cutting member. The shaving operation described can be performed when the internal cutting member is operated to rotate and the external cutting member 120 actually comes into contact with a portion of the skin at the position of the cutting trajectory surface. The internal cutting member is activated in a manner known by the drive mechanism of the shaver 100, which has an electric motor. The body 110 optionally houses the drive mechanism together with an internal power source (e.g., a battery). When the combination of the external cutting member 120 and the internal cutting member is moved over a part of the skin while the internal cutting member is rotated, the hairs protruding from that part of the skin are captured within the hair entry opening 122 of the external cutting member 120 and cut at that location.

[0042] It should be noted that the present invention also covers electric shavers and shaving units having one or more hair cutting units of different types than those already described herein. In particular, the present invention also covers electric shavers and shaving units having a hair cutting unit having an internal cutting member configured to reciprocate linearly with respect to an external cutting member.

[0043] The upper surface of the shaving unit 10 is provided with a skin contact surface 54, at least a portion of which is formed by, or forms a light-emitting surface 36 for an integrated lighting module inside the shaving unit 100, as will be further described below.

[0044] It should be noted that the above general information relating to the electric shaver 100 according to the first embodiment of the present invention (which will be described later) is applicable to (but not necessarily essential to) all embodiments of the present invention described later.

[0045] Figure 2 shows an exploded view of an exemplary shaving unit 10 according to one or more embodiments. In particular, Figure 2A shows a partial cutaway view of the interior of the shaving unit 10, and Figure 2B shows a wide-ranging exploded view of the shaving unit. Figure 3 shows a cross-section of the shaving unit 10 along line A shown in Figure 3. Figure 4 shows a bottom view of a portion of the interior of the shaving unit 10. Figure 5 shows a cross-sectional view of the shaving unit 10 along line B shown in Figure 5.

[0046] The shaving unit 10 comprises a lighting module 14 which includes a lighting module housing 18 that accommodates one or more lighting elements 20. In this example, the lighting module housing 18 is positioned 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 the upper portion of the shaver unit housing, and the support member 22 serves to support one or more hair cutting units 12 and the lighting module 14. The lighting module housing 18 defines one or more openings 56 into which one of each of the one or more hair cutting units 12 in the shaving unit 10 is disposed. However, this formation is not essential. For example, the lighting module may be a completely separate structural unit integrated within a separate housing of the shaving unit. The depicted design provides additional structural efficiency but is not essential to the concept of the present invention.

[0047] The lighting module 14 further comprises electrical connection pins 23 extending downward from the lighting module 14, which electrically contact complementary electrical contacts within the body 110, to provide an electrical connection between the lighting module 14 and the shaver body 110 in the assembled configuration.

[0048] The lighting module housing 18 defines an internal cavity 32, and the lighting element 20 is positioned within the cavity 32. The cavity 32 is on the skin-facing side of the lighting module housing 18 and is covered by the upper wall 34 of the lighting module housing. The upper wall incorporates a skin-facing light-emitting surface 36, and during the operation of the shaving unit, the light generated by the lighting element 20 is exposed to the skin through the skin-facing light-emitting surface 36. The upper wall 34 is made of an optically transparent material, which provides the light-emitting surface. In other examples, the upper wall 34 may incorporate a light-emitting surface as a partial region within a wider wall region such that the light-emitting surface forms a light-emitting window through the upper wall.

[0049] In the illustrated example, the lighting module housing 18 further comprises side walls 50a and 50b that define the cavity 32 in combination with the upper wall 34 of the lighting module housing 18.

[0050] In the illustrated example, the upper wall 34 of the lighting module housing 18 defines at least partially the skin contact surface 54 for the shaving unit 10, and the aforementioned light-emitting surface 36 incorporated into the upper wall 34 is positioned to contact the skin during the operation of the shaving unit.

[0051] The lighting module housing 18 may be a one-piece molded structure in some examples. It may also be an injection-molded component. It may be made of plastic.

[0052] The lighting module 14 includes a holder such as a printed circuit board (PCB) 38 located within the cavity 32, and the lighting element 20 is mounted on the first main surface 42 of the PCB (best visible in Figure 3) facing the upper wall 34 of the lighting module housing 18, so that the lighting element 20 is optically connected to the light-emitting surface 36 during the operation of the shaving unit 10.

[0053] The cavity 32 contains an optically transparent potting material 40 (best visible in Figure 3) that seals the lighting element 20 by covering the first main surface 42 of the PCB. The potting material 40 extends between the first main surface of the PCB 38 and the upper wall 34 of the lighting module housing 18. The potting material 40 also covers the second main surface 44 of the PCB 38 (i.e., the opposite or bottom surface of the PCB 38) opposite to the first main surface 42. The potting material 40 thereby seals the PCB 38 on all major sides. The potting material provides a heat conduction path between the lighting element 20 and the light-emitting surface 36 within the lighting module 14, thus creating thermally conductive contact between the lighting element 20 and the light-emitting surface 36. The potting material 40 also provides a waterproof function, as will be further described below.

[0054] The illumination element 20 is adapted to produce a skin heating effect on the light-emitting surface 36 of the illumination module housing 18 when it comes into contact with the skin during operation. In other words, when the illumination element 20 of the illumination module 14 is activated during a shaving operation, exposure to thermal stimulation is achieved, which results in an improvement in skin condition or appearance and / or an improvement in shaving comfort. In the illustrated example, this is achieved by including one or more infrared (IR) or near-infrared (NIR) illumination elements 62 within the illumination element 20. These provide light emission with a dominant frequency component in the IR or NIR band of the electromagnetic (EM) spectrum. The IR or NIR band has a particularly deep penetration depth into the skin. The optically transparent material of the upper wall 34 and / or potting material 40 of the illumination module housing 18 may have a light transmittance profile in which at least one peak of the light transmittance profile is in the optical wavelength range of 800 to 1050 nm, so as to maximize the photo-coupling from the IR or NIR illumination elements 20, 62 to the light-emitting surface 36.

[0055] In addition to the photo-induced skin heating effect of the IR or NIR lighting elements 20 and 62, which results from the absorption of IR or NIR light emitted by the lighting elements 20 and 62 by skin tissue, the lighting element 20 also provides a conduction-induced skin heating effect as a result of the heat conduction path between the lighting element 20 and the light-emitting surface 36 provided by the potting material 40. As a result of the above heat conduction path, the light-emitting surface 36 is heated by the thermal energy that would otherwise be dissipated from the lighting element 20 due to the limited electrical-to-optical conversion efficiency. Consequently, during the shaving process, the skin also heats up by conduction as it comes into thermally conductive contact with the light-emitting surface 36. By combining the photo-induced and conduction-induced skin heating effects, the skin heating efficiency of the lighting module 14 in the shaving unit 10 is increased.

[0056] It is not essential that the illumination element 20 includes an IR or NIR illumination element, because photo-induced heating can be achieved, for example, using a visible light illumination element and other parts of the EM spectrum. In some cases, optical components such as lenses can be used in combination with the visible light illumination element to focus or concentrate the light emission, thereby increasing the thermal output of the light at the light emission surface.

[0057] Furthermore, while at least one function of a lighting module is to produce a heating effect, light emission can also produce other beneficial effects on skin tissue. For example, blue visible light is known to be beneficial in treating acne, and red visible light is known to be beneficial in promoting wound healing and treating skin inflammation.

[0058] In the illustrated example, in addition to the IR or NIR illumination element 62, the set of illumination elements 20 further includes one or more visible light illumination elements 64 for indicating the activation of the IR or NIR illumination element in visible light. These are configured to operate when the IR or NIR illumination element is activated, either by active control by a control device or via a parallel wiring configuration with the IR / NIR illumination element 62 in a circuit configuration that supplies power to the IR / NIR illumination element 62. However, in further examples, the visible light illumination elements may be omitted.

[0059] If a visible light illumination element 64 is provided, the optically transparent material of the upper wall 34 and / or potting material 40 of the illumination module housing 18 may have at least one additional peak in light transmittance within the optical wavelength range of 450 to 700 nm so as to maximize the optical coupling from the visible light illumination element 64 to the light-emitting surface 36.

[0060] Each of the one or more illuminating elements 20 may, in some examples, be an LED. In the examples of IR or NIR illuminating elements 20 already described herein, the LED is configured to emit light having wavelengths mainly in the range of 915 to 965 nm.

[0061] In some examples, one or more lighting elements 20 are each equipped with LEDs, and each of the one or more LEDs is configured to emit light having wavelengths primarily in the range of 525–575 nm, 675–725 nm, or 775–825 nm. Optical-thermal simulations were performed considering the wavelength-dependent optical properties of the epidermis and dermis of human skin and the wavelength-dependent electrical-to-optical energy conversion efficiency of the LEDs. These simulations showed that the power required to achieve a predetermined thermal depth profile in human skin within a predetermined time is significantly lower when using LEDs that primarily emit within one of the three wavelength ranges described herein than when using LEDs that primarily emit within the IR or NIR wavelength range. In particular, the above predetermined thermal depth profile includes a first predetermined average temperature (e.g., 41.7°C) over the thickness of the epidermis (200 μm) and a second predetermined average temperature (e.g., 39.0°C) over the thickness of the dermis (1800 μm). These simulations assumed that the conversion efficiencies of LEDs emitting light within the wavelength ranges of 525-575nm, 675-725nm, 775-825nm, and 915-965nm were approximately 13%, 38%, 32%, and 30%, respectively. According to these simulations, while the power requirement for an IR LED was 3.9W, the power requirements for LEDs emitting light within the wavelength ranges of 525-575nm, 675-725nm, and 775-825nm were 2.46W, 2.22W, and 3.03W, respectively. Therefore, using an LED emitting light within any of these three wavelength ranges significantly reduces the battery power required by the battery in the main unit 110 supplying power to the lighting module 14 compared to using an IR LED or NIR LED. The lighting module 14 is electrically connected to the PCB 38 and includes one or more electrical connection members 23 (connection pins) that extend from the second main surface 44 of the PCB through the potting material 40 to the outside.

[0062] With respect to the potting material 40, it is intended to provide a dual function: to suppress the intrusion of moisture or other contaminants (such as dust or dirt) into the cavity 32, and further, to provide a thermal bonding function from the lighting element 20 to the light-emitting surface 36 (and thus to the skin surface during normal use of the electric shaver 100).

[0063] Preferably, the potting material 40 extends seamlessly from the first main surface 42 of the PCB 38 to the upper wall 34 of the lighting module housing 18. In other words, this defines at least one seamless 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 PCB 38 to the light-emitting surface 36 in the upper wall 34 of the lighting module housing 18, thereby optimizing heat conduction.

[0064] Preferably, the manufacturing of the lighting module 14 should be such that bubbles in the potting material 40 are minimized or, in particular, eliminated, because bubbles reduce the overall thermal conductivity of the heat conduction path from the first main surface 42 of the PCB to the light-emitting surface 36. Bubbles also negatively affect the uniformity of the temperature distribution. One particularly advantageous manufacturing method will be outlined later in this disclosure.

[0065] Preferably, the potting material 40 extends seamlessly as a continuous monolithic structure between the PCB 38 and the light-emitting surface 36. This should include at least one seamless solid path from the PCB 38 to the light-emitting surface 36.

[0066] During the assembly of the lighting module 14, it is preferable that the potting material 40 is applied to the entire surface of both the main surfaces 42 and 44 of the PCB 38.

[0067] To effectively prevent moisture intrusion, there should be a chemical bond or adhesion between the potting material 40 and the first main surface 42 and the second main surface 44 of the PCB 38. A chemical bond should also exist between the potting material 40 and the inner surfaces of the cavity 32, i.e., the inner surface of the top wall 34 and the inner surfaces of the side walls 50a and 50b.

[0068] For effective waterproofing, preferably, a chemical bond or adhesion should exist between the potting material 40 and the electrical contact pin 23. This helps prevent water from entering through the surface of the electrical contact pin 23.

[0069] Preferably, the potting material 40 at least partially covers the edge surface 46 of the PCB 38 that extends between the first main surface 42 and the second main surface 44.

[0070] Suitable materials for the potting material 40 include, for example, adhesive resins, such as silicone resins or epoxy resins. However, generally any sealing or filler material may be used. Preferably, the material exhibits the following properties within the functional temperature range of the lighting module 14: (a) no phase change, (b) its mechanical, thermal, or optical properties remain (substantially) unchanged, and (c) no discoloration. The functional temperature range is, for example, -10°C to 100°C, and the actual target operating temperature is typically about 40 to 60°C. A wider temperature range allows for changes in environmental conditions, such as shavers left in cold outdoor environments or shavers left in hot cars under sunlight.

[0071] The potting material 40 comprises an optically transparent 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 light emitted by the illumination element 20. The base potting material comprises a resin, such as a silicone resin or epoxy resin, a silicone curing gel, or another epoxy mixture. Examples of suitable ceramic particle materials include TiO2, Al2O3, BeO, AlN, and SiC. The ceramic particles embedded in the base potting material improve heat transfer from the illumination element 20 through the potting material 40 to the light-emitting surface 36 of the illumination module 14. At the same time, the ceramic particles improve the dispersion of the light generated by the illumination element 20 across the light-emitting surface 36 of the illumination module 14 via light scattering. As a result, heat transfer loss is reduced, and thermal hot spots on the light-emitting surface 36 caused by uneven dispersion of light are largely prevented.

[0072] If the size of the ceramic particles is smaller than the wavelength of light emitted by the lighting element 20, most of the light scattering caused by the ceramic particles is forward scattering. The density of the ceramic particles can be selected to maximize light scattering and minimize light loss. The optimal particle density depends on the distance between the PCB 38 and the light-emitting surface 36 of the lighting module 14.

[0073] The size and density of the ceramic particles embedded in the base potting material vary depending on their location within the cavity 32. Near the side walls 50a and 50b of the cavity 32, i.e., in locations away from the main optical path, the size and density of the ceramic particles may be selected to optimize heat conduction. In particular, in these locations, the size of the ceramic particles may be relatively large, and the density of the ceramic particles may be set to the maximum value that the base potting material can contain. Potting materials with different ceramic particle properties may be separated from each other within the cavity 32 by transparent separation walls.

[0074] Regarding the optical functionality of the illumination module 14, optionally, as shown in Figures 2 to 4, the illumination module may further comprise an optical device for generating visible light emission provided on the light-emitting surface 36 by an optional visible light illumination element 64. In this example, this comprises a light guide component 412 configured to guide the visible light generated by the visible light illumination element 64 to at least one area of ​​the light-emitting surface 36 of the illumination module 14. The light guide component 412 comprises a light guide sheet or film disposed in contact with or on the first main surface 42 (upper surface) of the PCB 38. This is bonded to the PCB 38 with an adhesive layer. This may also be a light guide sticker. In some examples, this can guide light in a direction having a main directional component parallel to the light-emitting surface 36. Optionally, light attenuation elements may further be provided to suppress or attenuate the direct optical path from each visible light illumination element 64 to the light-emitting surface 36. Each light attenuation element may be supported by a light attenuation layer, which comprises, for example, a light attenuation mask layer deposited on an optically transparent retaining layer disposed on a light guide component. These features will be described in more detail later in this disclosure.

[0075] Regarding the optical functionality of the lighting module 14, in some examples, the entire lighting module housing 18 may be made from the aforementioned optically transparent material (on which the light-emitting surface 36 is formed). This material may be optically semi-transparent, for example, scattering, so that the inside of the cavity 32 of the lighting module 14 is not directly visible from the visible surface of the shaving unit 10. This allows the entire body of the lighting module housing 18 to provide a photo-coupling function from the lighting element 20 to the light-emitting surface 36 and skin contact surface 54 of the shaving unit 10. The lighting module housing 18 may optionally be a one-piece injection-molded polymer structure.

[0076] As previously mentioned, the lighting module housing 18 in this example includes a skin contact surface 54 positioned to come into contact with the skin during the operation of the shaving unit 10. The light-emitting surface 36 forms at least a portion of this skin contact surface 54. The skin contact surface 54 defines one or more openings 56 into which one or more hair-cutting units 12 of the (assembled) shaving unit 10 are disposed. In the illustrated example, each of the one or more hair-cutting units 12 is completely surrounded by the skin contact surface 54, but this is not mandatory (for example, in a foil shaver configuration, the skin contact surface may extend only around some of the sides of each of the elongated hair-cutting units).

[0077] As can be seen in Figure 2, the light-emitting surface 36 of the illumination module 14 extends at least within the area of ​​the skin contact surface 54 between each of the multiple hair cutting units 12.

[0078] In the examples shown in Figures 2 to 5, all illumination elements 20 are mounted on the first main surface 42 of the PCB facing the light-emitting surface 36. However, this is not mandatory. In some embodiments, one or more of the illumination elements 20, in particular one or more visible light illumination elements, may be mounted on the second main surface 44 (i.e., the lower surface) of the PCB.

[0079] Figure 4 is a lower view of the PCB 38 of a lighting module in such an example. Figure 4 is a partially cutaway view showing the components on the second main surface 44 (i.e., the lower surface) of the PCB 38. In this example, a plurality of visible light illumination elements 64 are provided on the second main surface of the PCB. These may be provided in addition to, or instead of, the visible light illumination elements on the first main surface 42 of the PCB 38 described above.

[0080] In some embodiments, at least one temperature sensor 350, such as a thermistor, may be further provided on the PCB 38 (see Figure 5). This is preferably positioned adjacent to at least one of the IR or NIR illumination elements 62. This is used by the control unit to adjust the output level of the IR or NIR illumination element 62 to regulate the temperature of the light-emitting surface 36. However, these functions are optional and may be omitted.

[0081] The lighting module may include one or more additional electrical components mounted on the PCB 38, such as one or more resistors 66, as shown in Figure 5.

[0082] Figures 6A to 6D schematically show steps that form at least part of a manufacturing method suitable for the lighting module 14 of the shaving unit 10 shown in Figures 2 to 5. The steps shown in Figures 6A to 6D are for assembling at least one section of the lighting module 14.

[0083] The method includes the step (210) of providing a lighting module housing 18 comprising an upper wall 34 having a light-emitting surface 36 and side walls 50a, 50b that combine with the upper wall 34 to define the cavity 32 of the lighting module housing 18 (Figure 6A). The upper wall 34 has an inner surface 72 facing into the cavity 32.

[0084] The method further includes the step of providing an illumination unit comprising a PCB 38 and one or more illumination elements 20 mounted on a first main surface 42 of the PCB 38 (steps not explicitly shown in Figures 6A to 6D). The illumination elements 20 may include IR or NIR illumination elements 62 and / or visible light illumination elements 64. The illumination unit may further include an optical device, for example, a light guide component 412 disposed on the first main surface 42 of the PCB 38.

[0085] The method further includes step 230 of placing a layer 41a of optically transparent potting material 40 on the inner surface 72 of the upper wall 34 (Figure 6B). Preferably, the inner surface 72 is coated with a layer of potting material over its entire surface.

[0086] The method further includes step 240 of installing the above-described lighting unit, which comprises a PCB 38 and lighting elements 62 and 64, on a layer 41a of potting material 40 in a cavity, with the first main surface 42 of the PCB 38 facing the upper wall 34, such that potting material 40 is applied to the first main surface 42 of the PCB and both lighting elements 62 and 64 are sealed by the potting material.

[0087] The method further comprises step 250 of providing an additional layer 41b of potting material 40 on the lighting unit so as to cover the second main surface 44 of the PCB 38 opposite the first main surface 42, and the lighting unit is completely sealed by the potting material on the first main surface 42 and the second main surface 44 of the PCB 38. The potting material also preferably covers the side edges 46a, 46b of the PCB 38.

[0088] The method further includes a step of hardening the potting material.

[0089] The result of this method is a PCB 38 comprising lighting elements 62, 64 integrated and supported within a lighting module housing 18, which is coated and sealed on all sides with potting material 40. The potting material has a chemical bond to all parts it is in contact with.

[0090] The method further includes the step of including an illumination module 14 as part of the shaving unit 10 such that, during the operation of the shaving unit, the light-emitting surface 36 comes into contact with the skin when the shaving unit is placed against the user's skin to perform shaving. This step is achieved by assembling the illumination module 14 onto the support member 22 of the shaving unit 10 during a subsequent manufacturing process of the shaving unit 10.

[0091] The curing step may be performed as a single step after both layers 41a and 41b of the potting material have been deposited, or the first curing step may be performed after the first layer 41a has been deposited and the lighting unit has been positioned, and then the second curing step may be performed after the second layer 41b has been deposited on the lighting unit.

[0092] The above method achieves particularly effective sealing and further minimizes the formation of air bubbles in the potting material layer, resulting in optimal thermal conductivity and temperature uniformity of the potting material.

[0093] Instead of depositing the potting material 40 in a two-layer deposition process, a single, deeper layer of the potting material may be deposited in the cavity 32, and then the lighting unit may be immersed in the potting material. However, this is not very practical, especially when implemented in mass production.

[0094] Preferably, the potting material 40 is a material whose light transmittance (through the light-emitting surface 36) from the IR or NIR illumination element 62 to the outside of the illumination module 14 is at least 90%.

[0095] Optionally, the lighting module housing 18 may be formed of an optically transparent material, in which case preferably the light transmittance of light from the IR or NIR lighting element 62 to the outside of the lighting module 14 by this material is at least 70%.

[0096] Preferably, the potting material 40 and the lighting module housing 18 have a thermal conductivity of at least 0.2 W / mK.

[0097] Preferably, the specific heat capacity of the potting material 40 is at least 800 J / KgK.

[0098] Preferably, the specific heat capacity of the lighting module housing 18 is at least 1250 J / KgK.

[0099] The operating temperature range for the IR LED or NIR LED is optionally -10°C to 100°C.

[0100] Optionally, the operating temperature range of the potting material 40 is -10°C to 100°C.

[0101] Optionally, the operating temperature range of the lighting module housing 18 is -10°C to 80°C.

[0102] Preferably, the potting material 40 should have chemical resistance and its material properties should be robust to frequent temperature cycles.

[0103] The electric shaver 100 further includes a control device (not shown) for controlling the lighting element 20. The control device is housed within the shaver body 110. The control device includes at least one processor. The control device is configured to receive signals or data from one or more sensors included on the PCB, such as a temperature sensor.

[0104] According to at least one set of embodiments of the present invention, a novel control scheme for the illumination element 20 for optimizing the temperature control of the light-emitting surface 36 can be provided. The shaving unit 10 in this example may be the same as or similar to that described above. In particular, all the features of the electric shaver 100 and shaving unit 10 described above are compatible with this set of embodiments of the present invention, although some may be omitted. For example, the potting material described above is not essential in this set of embodiments of the present invention.

[0105] According to one or more embodiments, an electric shaver 100 is provided, comprising a shaver unit 10 (for example, as described above), and a control device operably coupled to a lighting module 14 and adapted to control a lighting element 20 in a drive scheme comprising at least first and second stages. The control device may be housed within the shaver body 110. The drive scheme comprises an initial heating stage triggered when the lighting module is started, in which the lighting element 20 is driven at an initial output setting. The drive scheme further comprises an operating stage following the initial heating stage, in which the lighting element 20 is driven at an operating output setting. The maximum output value of the operating output setting is lower than the output value of the initial output setting. The initial heating stage targets a predetermined target temperature with respect to the light-emitting surface 36. This stage may be performed implicitly (blindly) by executing a predetermined power profile for a predetermined duration known or expected to bring about the target temperature. Alternatively, this stage may be performed actively by using input from a temperature sensor as feedback to manipulate either or both the output setting and / or duration of the initial heating phase.

[0106] In some examples, during the operating phase, the temperature of the light-emitting surface is controlled to be maintained at a predetermined temperature by active control of the operating output settings. This may be achieved, for example, by utilizing a temperature sensor to provide active feedback.

[0107] The initial heating phase has a higher (initial) power setting to rapidly warm the light-emitting surface 36 to the target temperature desired for operation. This reduces the waiting time before using the shaver and improves user convenience. However, if this initial power setting is maintained throughout the shaving session, it may result in light emission on the light-emitting surface 36 exceeding what is considered comfortable or safe for the user. Therefore, in the second (operational) phase, the (time-averaged) power setting is reduced so that the temperature is maintained but the light emission is comfortable and safe for the user.

[0108] For further explanation, and without the intention of limiting the scope of the present invention, examples of the first and second stages are schematically shown in the graph of Figure 7. This shows the initial heating stage (1) and the subsequent operating stage (3), separated in time by a short intermediate transition stage (2), during which the output setting is reduced from the initial output setting to a lower operating output setting. Figure 7 shows the optical power density at the light-emitting surface during each operating mode (line A, unit: mW / cm²). 2 The temperature at the light-emitting surface 36 in each mode (line B, unit: °C) is shown as a function of time (unit: seconds).

[0109] The target temperatures for the initial heating phase 310 and the operating phase 320 can be modified as desired, typically based on the user's expected comfort and safety thresholds. Figure 8 provides an exemplary overview of various applicable skin temperature profiles that cause discomfort and burns (i.e., the maximum permissible skin temperature as a function of contact time with the heat source). Line C corresponds to full-thickness skin burns. Line D corresponds to mid-thickness skin burns. Line E corresponds to discomfort.

[0110] In at least one preferred embodiment, the predetermined target temperature for the initial heating stage and the operating stage may be in the range of 40°C to 50°C. More specifically, the predetermined temperature may be in the range of 41.8°C to 42.2°C, 44.8°C to 45.2°C, or 47.8°C to 48.2°C. These temperature ranges are based on the following considerations.

[0111] Since the light-emitting surface 36 comes into contact with the skin during use, this temperature range aims to be within the acceptable range of comfort expected by the user. For example, the normal temperature of the face is around 36°C (this may vary depending on environmental conditions). The average person's sensory sensitivity is about 2°C. Adding this 2°C gives 38°C, which is the temperature at which the heating effect can be perceived. Furthermore, considering that the temperature should be the highest possible value within the limits of safety and comfort in order to maximize the sensory benefit to the user, an appropriate lower limit range is considered to be 42-43°C. This temperature has been found to be comfortable for the user and effective in terms of providing skin benefits.

[0112] The upper temperature limit is selected based on both perception and preference, and further, on compliance with safety standards. These indicate that the maximum skin temperature must be 48°C or lower. For example, referring to Figure 8, line E shows that for longer contact times of 10 seconds or more, a temperature of 48°C is just below the minimum temperature at which the user will experience discomfort. Assuming a system temperature accuracy of 0.05°C, the upper temperature limit is set to 47.95°C.

[0113] Since user preferences regarding target temperatures may vary, electric shavers in some embodiments include an input component configured to allow the user of the electric shaver to select a predetermined temperature. An upper limit may be set on the selectable temperature, such as 48°C in some examples, to prevent the user from exceeding safety limits. The input component is operably coupled to the control device described above. Multiple predetermined temperature settings may exist that the user can select. Alternatively, the control device and input component may allow the user to freely select any target temperature within a certain temperature boundary.

[0114] As one example, the following are example of predetermined temperature settings for a (predetermined) target temperature that can be selected using the input component:

[0115] [Table 1]

[0116] The initial heating phase 310 can be automatically triggered when the device is switched on. During the initial heating phase, the optical power is kept fixed at a relatively high setting, and the temperature of the optical emission surface 36 rises rapidly. Once a predetermined target temperature is reached, the control device moves to the operation phase 320. Temperature feedback is used to change the optical emission in the operation phase 320 to stably maintain the predetermined target temperature (steady state phase).

[0117] To promote the heating of the light-emitting surface 36, the initial output setting during the initial heating phase 310 is set to be higher than the maximum output value used during the subsequent operating phase 320. Increasing the output increases the optical power density at the light-emitting surface 36, and thus increases the heat transfer coefficient to the light-emitting surface 36. When promoting heating, it is necessary to balance comfort and safety, as noted above. In addition to managing the target maximum temperature, it is preferable to manage the maximum optical power density provided at the light-emitting surface 36 by the lighting element 20.

[0118] The objective in this regard is to measure the total light energy density (in J / cm²) supplied to any spot on the user's skin over a continuous period of time while the device is in use. 2 The goal is to limit the amount of light supplied to a given spot on the skin so that it does not exceed a predetermined safety threshold. Continuously applying light energy to any one spot on the skin means accumulating thermal exposure at that spot, which can lead to discomfort or burns if the total light energy density supplied over a continuous exposure period is too high. The total light energy density supplied to a region of the user's tissue over any continuous time window is equal to the time-averaged light power density supplied over that region (by the light-emitting surface in contact with that region) (unit: W / cm²). 2) is a function of the time window length. Since the user cannot directly control the length of time the light-emitting surface is exposed to a single tissue spot, it is advantageous to control the maximum optical power density provided on the light-emitting surface over the initial heating phase, depending on the worst-case user scenario regarding the duration the user is exposed to a single tissue region.

[0119] The optical power density across the light-emitting surface generally varies as a function of position on the light-emitting surface. According to one or more embodiments, the heating step is performed at a point or region of the light-emitting surface where the optical power density has its maximum value during the initial heating step, with the maximum optical power density being 325 mW / cm². 2 From 360 mW / cm² 2 It was configured to be so.

[0120] This is a safety constraint based on the assumption of a worst-case user scenario in which the user exposes the light-emitting surface to a single, fixed spot on the user's tissue for 10 seconds. Studies have shown that, in the normal use of any shaver, 10 seconds is a typical upper limit for the time a user holds the shaver stationary over any single point before moving it again. Therefore, it is reasonable to assume a maximum exposure time of 10 seconds. Furthermore, this time limit may also be implemented by setting the duration of the initial heating phase to 10 seconds (after which the operation phase is triggered and the optical power on the light-emitting surface decreases), in which case it is impossible for the user to exceed a 10-second exposure time at the initial power setting. The maximum optical power density at any spatial point / region across the light-emitting surface is 360 mW / cm², which is the upper end of the above range. 2 Therefore, if the user exposes the light-emitting surface to the same stationary spot for a maximum of 10 seconds, this results in a total supplied light energy density exposure of the tissue at the aforementioned stationary spot of 3.6 J / cm². 2 This corresponds to a maximum light energy exposure of 3.6 J / cm². 2 Compliance with the safety regulations of the IEC / EN62471 standard concerning the "photobiological safety of lamps and lamp systems" is guaranteed.

[0121] Of course, it should be noted that the above range of the maximum optical power density is only an example and is not intended to limit the concept of the present invention. For example, the range may be changed if different assumptions are made regarding the application time of the user and / or if different regulatory constraints exist. For example, assume that the user receives instructions regarding the maximum time (e.g., 5 seconds or 2.5 seconds) that the shaver should be applied to any one spot, and that the user follows those instructions. After any stationary hold at one spot of the device for a predetermined length of time, an automatically generated (e.g., auditory or tactile) feedback prompt may be issued.

[0122] Assuming this, the maximum optical power density at the light emitting surface may be greater than 360 mW / cm described above. 2 For example, if the continuous application time to the tissue is 5 seconds or less, the maximum time-averaged optical power density of the light emitting surface during the initial healing stage can be set to a maximum of 600 mW / cm. 2 If the assumed maximum exposure time is even shorter at 2.5 seconds, the maximum optical power density will be even greater at 1 W / cm. 2 The initial warming period can also be set to have the same length as these maximum time periods, but these may not be long enough to achieve the desired target surface temperature.

[0123] How much to trust that the user will not exceed the expected maximum exposure time at one spot is a design choice. To balance safety aspects, an assumed exposure time of 10 seconds (which is in line with the natural behavior pattern of the user) is preferred. In this way, the skin temperature can be controlled to be kept below a predetermined maximum temperature (e.g., 48 °C), and the light energy exposure can be kept below 3.6 J / cm in accordance with the safety regulations of the IEC / EN62471 standard. 2

[0124] ​The lighting module typically comprises spatially arranged IR or NIR illuminating elements 62, and the irradiance (light power per unit area) provided at the light-emitting surface varies depending on the illuminating elements 62. In this respect, the irradiance can vary due to differences in the optical path length between each IR or NIR illuminating element 62 and the light-emitting surface.

[0125] From the above perspective, according to one or more embodiments, the lighting module is configured such that at least one light beam among the IR or NIR lighting elements 62 has the highest average light power density at the light-emitting surface during the initial heating stage, compared to the other IR or NIR lighting elements, in which case the output value of the initial output setting is such that the highest average light power density is 325 mW / cm². 2 From 360 mW / cm² 2 It is necessary to ensure that the following occurs. The average optical power density at the light-emitting surface provided by the light beam of a given illumination element refers to the average value of the optical power density measured in the cross-section of the light beam at the light-emitting surface during the initial heating phase. Here, it is assumed that the light beams of different IR or NIR illumination elements do not overlap at the light-emitting surface. Therefore, depending on their positions within the illumination module 14, one or more of the IR or NIR illumination elements will provide the highest average optical power density at the light-emitting surface. The initial output setting is such that this highest average optical power density is 325 mW / cm². 2 From 360 mW / cm² 2 It is necessary to ensure that this is the case. In embodiments in which the illumination element provides overlapping light beams on the light-emitting surface, the initial output setting during the initial heating stage should be such that, for example, the maximum light emission density at any position on the light-emitting window is within the above-described range of light emission densities.

[0126] The optical power density provided by a given illuminating element 62 depends on the power supply of the illuminating element, and further on the optical path length from the illuminating element to the light-emitting surface.

[0127] For example, see Figure 9 (left), which shows an example of the positional relationship between the light-emitting surface 36 and the IR / NIR illumination element 62 for the exemplary shaving unit 10. The illumination elements 62 are arranged in space to form multiple (in this case, four) groups or clusters. Each group may contain at least one IR / NIR illumination element 62, but may also contain two or more IR / NIR illumination elements. The illumination element groups include a central group 510, as well as a first peripheral group 520a, a second peripheral group 520b, and a third peripheral group 520c. Figure 9 (right) shows the radiation pattern of a typical IR / NIR LED illumination element 62. This shows that the maximum angular range of typical radiation is 60 degrees on both sides of the vertical optical axis of the LED.

[0128] From this perspective, the central group 510 of one or more IR / NIR illumination elements 62 has a larger illumination area on the light-emitting surface and the best contact with the skin, but the distance between the IR / NIR illumination elements is greater compared to the peripheral group of IR / NIR illumination elements, resulting in <300 mW / cm². 2 It can be determined that the average illumination level is lower. The greater distance between the central group 510 and the light-emitting surface is due to the slight convex curvature of the illumination module housing 18, and the apex of the convex curvature coincides with the position of the central group of illumination elements.

[0129] In this example, within the region between the four groups of IR / NIR illumination elements 62 (the region between the blue circles), the skin contact surface is substantially unaffected by irradiation from the IR / NIR illumination elements, and therefore this region is heated only by conduction.

[0130] The options for controlling the lighting element 20 to carry out the initial heating stage 310 and the operation stage 320 will be examined in more detail below.

[0131] With regard to the control of the lighting module 14, the activation of the lighting module 14 is triggered by the activation of one or more hair cutting units 12. For example, the activation of the initial heating phase is triggered by the activation of one or more hair cutting units (i.e., the switch-on of the electric shaver). This simultaneous activation may be achieved by simultaneous control of the electric shaver 100 by the aforementioned control device, or it may be automatically triggered by the parallel wiring configuration between the cutting units 12 and the lighting module 14.

[0132] In addition to, or instead of, this control configuration, the electric shaver 100 may include further input members (e.g., switches or other input devices) configured to allow the user of the electric shaver to start and / or stop the lighting module 14 independently of the activation of one or more hair cutting units 12. This allows the user to choose whether to use the shaver's hair cutting function with or without the heating function. The electric shaver control unit may have an initial setting in which the lighting module is triggered when the hair cutting units are activated, but the user can stop the lighting module using further input members.

[0133] With respect to the predetermined temperature target setting mentioned above, temperature feedback is provided to the control device using the temperature sensor 350 during either the initial heating phase or the operating phase, or both. The temperature sensor can be mounted on the same PCB 38 that holds the illumination elements 20. For example, the temperature sensor 350 is mounted on the previously discussed first main surface 42 of the PCB in a position adjacent to one of the illumination elements, for example, one of the IR or NIR illumination elements. The temperature sensor 350 can be seen, for example, in the cross-sectional view of Figure 5. By placing the temperature sensor directly adjacent to the illumination elements, the thermal coupling between the two is optimized.

[0134] The heat conduction path between the first main surface 42 of the PCB facing the light-emitting surface 36 and the light-emitting surface 36 is provided by the optically transparent potting material 40, which has already been described, and is provided so as to cover the first main surface 42 of the PCB 38, thereby sealing the illumination element 20 and the temperature sensor 350. The potting material also provides thermal coupling between the temperature sensor 350 and the light-emitting surface 34, thereby increasing the accuracy of the temperature sensor when measuring the surface temperature.

[0135] A schematic representation of a portion of an exemplary control circuit is shown in Figure 10. This circuit includes circuit components within the illumination module 14 (in the shaving unit 10) and further within the shaver body 110. In this example, the illumination module comprises an illumination element 20 and further comprises a temperature sensor 350 (e.g., a thermistor). The body 110 comprises a control device 86. The control device 86 is configured to control the duration of the initial heating phase. The control device is further adapted to control the output level of the illumination element 20 in response to the detected emission from the temperature sensor 350 during the operating phase. For example, the control device is thus configured to adjust the temperature of the light-emitting surface 36 in response to the output from the temperature sensor via control of the illumination element 20.

[0136] The main circuit in the illustrated example further includes a battery ("BAT") for supplying power to the lighting module 14, an electrical connection to the lighting module for supplying power to the lighting module, and a signal connection to the lighting module for receiving detection signals from the temperature sensor 350.

[0137] Controlling the output level of a lighting element involves changing the duty cycle frequency of a pulse-wave modulation (PWM) drive scheme.

[0138] To control the lighting module to maintain a desired setpoint temperature, the lighting module is equipped with a temperature sensor 350, such as a thermistor, such as a negative temperature coefficient (NTC) thermistor.

[0139] The control device 86 can sample the signal from the temperature sensor 350 and process it to convert the sensor signal into temperature. Since temperature changes tend to take time, the sampling frequency of the temperature sensor is not important.

[0140] The obtained temperature values ​​are used in a closed-loop system to adjust the desired setpoint temperature.

[0141] Safeguards are incorporated to prevent overheating. For example, if the measured signal falls outside a certain operating bandwidth (indicating overheating), the lighting module will automatically shut down.

[0142] A variety of temperature control modules are available. In one particular example, the control device 86 includes a feedback control loop comprising a temperature sensor 350 and a proportional-integral (PI) control member.

[0143] The temperature of the shaving unit is controlled directly based on the temperature reading of the temperature sensor 350. Alternatively, the control device is adapted to determine a corrected temperature of the light-emitting 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 output level of the illumination element according to the corrected temperature of the light-emitting surface. Here, the corrected temperature is an estimated temperature at the skin-contact surface, which may differ from the direct temperature measured by the temperature sensor, for example. For example, the corrected temperature is calculated using a temperature calculation function applied to the temperature output from the temperature sensor.

[0144] According to one set of further embodiments, a novel optical device is provided within the shaving unit 10 for adjusting the visible light profile brought to the light-emitting surface 36 by one or more visible light illumination elements 64. The shaving unit 10 in this example may be the same as or similar to those described in relation to earlier embodiments. In particular, any of the features of the electric shaver 100 and shaving unit 10 described above are compatible with this set of further embodiments of the present invention, although some may be omitted. For example, a control scheme having an initial heating stage and an operating stage is not essential.

[0145] As an introduction to further embodiments of this set, it should be noted that it is advantageous to include a visible light illuminating element 64 among the multiple illuminating elements 20, whose primary function is to provide a visible light source to visually indicate to the user the activation of the heating function of the lighting module 14. The heating illuminating element generates light emission in the non-visible spectrum, which means that no visual feedback is provided to the user. By integrating light feedback in the visible region at the location of the light emission surface 36, the user can identify the operating status.

[0146] The objective of at least one set of embodiments of the present invention is to integrate a photoprocessing element with the shaving unit 10 to correct what would otherwise appear on the light-emitting surface 36 as an isolated point light source spot. This is schematically illustrated by Figure 11, which shows an exemplary visible light profile 65 generated on the light-emitting surface 36 by a visible light illumination element when no optical device is provided within the illumination module. Figure 12 shows a cross-section through an illumination module 14 without an optical device for guiding visible light. A forward-directing visible light illumination element 64 is shown mounted on the first (upper) main surface 42 of the PCB 38. The light-emitting surface 36 can be understood as having a proximity region 420 corresponding to the area of ​​the virtual projection 422 of the visible light illumination element 64 onto the light-emitting surface, as shown in Figure 12. For each individual illumination element, this proximity region 420 is relatively small, which means that the visible light generated by each visible light illumination element 64 appears to the observer 419 as a point light source on the light-emitting surface 36. However, this does not mean that the actual heat treatment is dispersed over a wider surface area of ​​the light-emitting surface 36.

[0147] Accordingly, according to one or more embodiments, the illumination module 14 further comprises an optical device for generating visible light emission provided by the visible light illumination element 64 on the light emission surface 36.

[0148] An example is schematically shown in Figures 13 to 15, and will be explained below.

[0149] A shaving unit 10 is provided, comprising a lighting module 14 having one or more infrared (IR) or near-infrared (NIR) lighting elements 62 and one or more visible light lighting elements 64 for generating visible light. Although only one visible light lighting element 64 is shown in Figures 13 to 15, more such elements may be provided in further examples. Both the IR or NIR lighting elements 62 and the visible light lighting elements 64 are arranged to be optically connected to the light-emitting surface 36. The visible light lighting elements 64 are configured and arranged to be activated together with the activation of the IR or NIR lighting elements 62 in order to visually indicate the activation of the IR or NIR lighting elements 62. The activation of the IR or NIR lighting elements 62 and the visible light lighting elements 64 is controlled, for example, by a control device.

[0150] As described above, the light-emitting surface 36 is understood to have one or more adjacent regions 420, each comprising a region of one virtual projection 422 of the visible light illumination element 64 onto the light-emitting surface 36. The optical device includes a light guide component 412 configured to guide the visible light generated by the visible light illumination element 6 to at least a main region 424 of the light-emitting surface, in which case the main region does not include one or more adjacent regions 420 of the light-emitting surface 36.

[0151] The optical device further comprises one or more light-attenuating elements 416, each positioned between one of the visible light illumination elements 64 and a proximity region 420 of the light-emitting surface 36 associated with each of the visible light illumination elements 64, each having a transmittance to visible light less than the transmittance to visible light of the light guide component 412. In the illustrated examples of Figures 13 to 15, each of the one or more light-attenuating elements 416 comprises a layer 450 of light-attenuating material, which may be partially light-attenuating (i.e., semi-transparent) or completely light-attenuating (i.e., opaque). In the illustrated examples, the layer 450 of light-attenuating material is deposited on a portion of a retaining sheet 472 that is otherwise light-transmitting (e.g., optically transparent) and extends over the light guide member 440 and the visible light illumination elements 64. In other examples, each of the light-attenuating elements 416 may be formed by an integral portion of the retaining sheet 472, for example, as a light-attenuating (e.g., colored) section of a sheet that is otherwise optically transparent.

[0152] The retaining sheet 472 may be optically transparent. However, in other examples, the retaining sheet may be optically transparent and at the same time optically diffusive or scattering in order to facilitate a more homogeneous distribution of light over the main region 424 of the light-emitting surface.

[0153] Figure 14 schematically shows the modified visible light profile provided to the light-emitting surface as a result of the light guide component 412. The light attenuation element 416 suppresses the direct optical path from each visible light illumination element 64 to the light-emitting surface 36, i.e., to the proximal region 420 of the light-emitting surface 36 associated with the visible light illumination element 64.

[0154] In the examples shown in Figures 13 to 15, the light guide component 412 includes a light guide member 440 configured to guide the visible light generated by the visible light illumination element 64 in an induction direction having a principal directional component parallel to the light emission surface 36. Each of the one or more visible light illumination elements 64 includes a side-view LED configured to introduce visible light into the light guide member 440, for example, via the edge surface 442 of the light guide member 440.

[0155] The light guide member 440 includes a light emission coupling element configured to couple visible light emitted from the light guide member 440 toward the light emission surface 36. For example, the light guide member may include an array of inclined light guide facets for reflecting or scattering light outward from the light guide member (not shown in Figures 13 to 16, but can be seen in Figure 17, for example).

[0156] Figure 15 shows an enlarged cross-sectional view of the PCB38 configuration in the embodiment shown in Figure 14.

[0157] Figure 16 shows a diagram of the skin contact surface 54 of the shaving unit 10, which in this case is formed by the upper wall 34 of the housing 18 of the lighting module 14. Figure 16 shows the light-emitting surface 36 which forms at least a portion of the skin contact surface 54. Figure 16 shows the spatially extended visible light emission realized by the optical device described above and shown in Figures 13 to 15. As shown, this corresponds to the main region 424 of the light-emitting surface shown in Figure 14, and the visible light of the visible light illumination element 64 is guided by the light guide component 412 of the lighting module 14.

[0158] The spatial locations of specific visible light illumination elements 64, as illustrated in Figures 13 to 15, are shown in Figure 16.

[0159] Figure 17 shows a perspective view of the PCB 38, lighting elements, and optical device of the lighting module shown in Figures 13 to 15. The visible light lighting elements 64 are mounted on the first main surface 42 of the PCB, which, when assembled, is positioned opposite the light-emitting surface 36 (not shown in Figure 17). The visible light lighting elements 64 are not directly visible in Figure 17 because they are mounted beneath a corresponding layer 450 of an opaque material and are hidden from view.

[0160] In the illustrated example, each visible light illumination element 64 is a side-emitting visible light illumination element. The light guide component 412 is shown in Figure 17. The light guide component comprises a light guide member in the form of a light guide sheet 460, which is placed on the first main surface 42 of the PCB. Layers 450 of light attenuation material, each forming a light attenuation element, are provided by placing an optically transparent retaining sheet 472 on the light guide sheet 460, and each light attenuation element is provided as an opaque masking ink layer 470 on the respective region of the optically transparent retaining sheet 472 in the direct optical path between each of the visible light illumination elements 64 and the light-emitting surface, for example, on the region directly above each corresponding visible light illumination element 64.

[0161] In this example, the light-attenuating material layer 450 is provided in the form of an opaque ink layer, but other options are possible. Instead of an opaque ink layer, a partially light-attenuating masking layer may be provided. Partially light-attenuating ink or another material can be used for these masking layers. An adhesive layer (e.g., a sticker) bonded to the relevant section of the retaining sheet 472 can be used for these masking layers. In some examples, these masking layers may have a hue, such as red.

[0162] Furthermore, as described above, while the retaining sheet 472 is optically transparent in the example described, the retaining sheet in other examples may be an optically transparent light-diffusing sheet in order to improve the homogeneity of the visible light profile brought to the light-emitting surface.

[0163] In the examples shown in Figures 13 to 17, the light guide member is a light guide sheet 460, which has an optical configuration that produces a light scattering or diffusion effect, dispersing the visible light emitted from the visible light illumination element 64 over a wider visible region of the light emission surface 36 of the illumination module 14. The visible light illumination element 64 may be a laterally directional visible light illumination element, in which case the light guide sheet 460 receives the visible light generated by the visible light illumination element 64 and guides it in an induction direction having a principal directional component parallel to the light emission surface 36 of the illumination module 14. The visible light illumination element 64 is received, for example, in a cavity, opening, or notch formed in the side wall 444 of the light guide member, in which case the light from the visible light illumination element 64 is introduced into the light guide member 440 via the edge surface 442 in this cavity within the light guide member 440.

[0164] The light guide member 460 includes a light emission coupling element 462 configured to couple visible light emitted from the light guide member toward the light emission surface. In the example shown in Figure 17, the light guide sheet 460 is structured to include a linear array of inclined planar facets 462 that function to scatter light and externally couple it toward the light emission surface 36 above the PCB 38.

[0165] The visible light illumination element 64 is located on the same PCB 38 as the IR or NIR illumination element 62.

[0166] Figure 18 shows a sectioned view of the illuminating module 14 illustrated in Figures 13 to 17. The light-emitting surface 36 of the illuminating module housing 18 forms the skin contact surface for the shaving unit. Inside the illuminating module housing 18 is a layered stack comprising a PCB 38 which holds IR / NIR illuminating elements 62 and visible light illuminating elements 64 mounted on its first main surface 42, a light guide sheet 460 mounted on the first main surface 42 of the PCB 38 (e.g., via adhesive), and optically transparent retaining sheets 472 on which an opaque ink layer 470 is deposited, each forming a light-attenuating element 416. This layered stack is sealed inside the illuminating module housing 18 by a potting material 40, as previously described. Figure 18 also shows electrical connection pins 23 provided on the second main surface 44 of the PCB 38 for connecting the illuminating elements 62, 64 to a power supply in the body of the shaver. Figure 18 does not show the potting material layer provided on the second main surface 44 of PCB 38.

[0167] In the example shown in Figure 17, both the visible light illumination element 64 and the IR or NIR illumination element 62 are mounted on the first main surface 42 of the PCB 38 facing the light-emitting surface 36. However, in an alternative set of embodiments, the IR or NIR illumination element 62 is mounted on the first main surface 42, and the visible light illumination element 64 is mounted on the second main surface 44 of the PCB opposite the first main surface 42, or on both the first main surface 42 and the second main surface 44 of the PCB 38. In this example, a portion of the PCB 38 itself acts as an optical attenuation element 416 for the visible light illumination element 64 mounted on the second main surface 44 of the PCB 38, suppressing the direct optical path between the visible light illumination element 64 on the second main surface 44 and the light-emitting surface 36.

[0168] An example is schematically shown in Figure 19. The visible light illumination element 64 is mounted on the second main surface 44 of the PCB 38. The one or more light attenuation elements described above are understood to be each formed by a corresponding portion of the PCB 38 on which one of the visible light illumination elements 64 is located.

[0169] In this case, the light guide component 412 includes a light guide and / or light reflecting portion 480 of the housing 18 of the lighting module 14. Therefore, in this case, the lighting module housing 18 itself forms at least a part of the light guide component. As shown in Figure 19, the inner surface 480 of the lighting module housing 18 is positioned to guide and / or reflect the visible light generated by the visible light illumination element 64 on the second main surface 44 of the PCB 38 toward the light-emitting surface 36. Furthermore, the housing 18 of the lighting module 14 may be integrally made from the same optically transparent material that forms the light-emitting surface 36, and the upper wall 34 and the side walls 50 of the housing 18 may constitute the light guide and / or light reflecting portion 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 the visible light emitted by the visible light illumination element 64 on the second main surface 44 of the PCB 38 and to couple the visible light to the light-emitting surface 36. In some examples, the body of the lighting module housing 18 is adapted to provide a scattering effect on visible light, thereby dispersing 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 to the entire upper wall 34 of the lighting module housing 18, as shown in Figure 20, for example.

[0170] In some examples, the light guide and / or light reflector 480 of the housing 18 of the lighting module 14 is arranged to cooperate with further light guide and / or light reflector portions of the hair cutting unit 12 and / or support member 22 (see Figures 1 to 3) to guide and / or reflect visible light generated by the visible light illuminating element 64 on the second main surface 44 of the PCB 38 toward the light-emitting surface 36.

[0171] For example, visible light reflective elements or reflective surfaces / interfaces may be formed on the body of the lighting module housing 18 and / or the body of the support member 22. The reflective surfaces are configured to produce a total internal reflection (TIR) ​​effect. Reflective and / or scattering elements are provided in or around one or more hair cutting units 12, and they are arranged to receive at least a portion of the visible light emission from the visible light illumination element 64.

[0172] In the example shown in Figure 19, the visible light illumination element 64 is mounted on the second main surface 44 of the PCB 38, but the use of an illumination module housing 18 made of a light-transmitting material for volume scattering of visible light can also be adapted for a visible light illumination element mounted on the first main surface 42 of the PCB.

[0173] Figure 21 shows further perspective views of the first main surface 42 (upper) and the second main surface 44 (lower) of the PCB 38 example shown in Figures 13 to 18.

[0174] The PCB 38 comprises a central region 502 from which several (in this case, three) elongated arms 504a, 504b, and 504c extend outward. Each arm of the PCB 38 has a narrower body section connected to the central region and a wider end section. Each of the wider end sections holds one or more IR or NIR illumination elements and at least one visible light illumination element. These may be referred to as the first peripheral group 520a, the second peripheral group 520b, and the third peripheral group 520c of illumination elements. The central region also holds one or more IR or NIR illumination elements and at least one visible light illumination element, and these may be collectively referred to as the central group 510 of illumination elements. At least one temperature sensor is provided on the PCB. The body sections of the arms of the PCB may not contain electrical components. When assembled, they hold light guide members 440, such as light guide sheets 460.

[0175] When assembled, as schematically shown in Figure 22, the central group of illumination elements 510 is located within the central region of the shaving unit 10 between the first hair cutting unit 12a, the second hair cutting unit 12b, and the third hair cutting unit 12c, and comprises a central IR or NIR illumination element 512 and at least three central visible light illumination elements 516.

[0176] The lighting module further comprises a first peripheral group 520a, a second peripheral group 520b, and a third peripheral group 520c of lighting elements, which are located within the first peripheral region, the second peripheral region, and the third peripheral region of the shaving unit 10, respectively, between the first hair cutting unit 12a and the second hair cutting unit 12b, between the first hair cutting unit 12a and the third hair cutting unit 12c, and between the second hair cutting unit 12b and the third hair cutting unit 12c, respectively, and each of these groups comprises a peripheral IR or NIR lighting element 522 and at least one peripheral visible light lighting element 524.

[0177] Figure 23 is a perspective view of a light guide member 440, which is mounted on the PCB 38 of Figure 21, in the form of the light guide sheet 460 already shown in Figures 13 to 18. The light guide member 440 has a plurality of arm geometry corresponding to the geometry of the PCB 38. In particular, it comprises a first portion 530, a second portion 532, and a third portion 534. When assembled, the first portion extends between a first of the central visible light illumination elements 516 and at least one peripheral visible light illumination element 524 of the first peripheral group 520a of the illumination elements. The second portion 532 extends between a second of the central visible light illumination elements 516 and at least one peripheral visible light illumination element 524 of the second peripheral group 520b of the illumination elements. The third portion 534 extends between a third of the central visible light illumination elements 516 and at least one peripheral visible light illumination element 524 of the third peripheral group 520c of the illumination elements. The illumination module further comprises light attenuation elements for the central visible light illumination element 516 and for the peripheral visible light illumination elements 524 (not shown in Figures 21 to 23), provided in the same manner as already described herein in relation to the embodiments of Figures 12 to 18.

[0178] As discussed above, a control device is used in the embodiment. The control device can be implemented in numerous forms using software and / or hardware to perform various necessary functions. A processor is an example of a control device that utilizes one or more microprocessors that are programmable using software (e.g., microcode) to perform the necessary functions. However, the control device may be implemented with or without a processor, and may be implemented as a combination of dedicated hardware for performing some functions and a processor (e.g., one or more programmed microprocessors and associated circuit configurations) for performing other functions.

[0179] Examples of control device components that may be used in various embodiments of this disclosure include, but are not limited to, conventional microprocessors, application-specific integrated circuits (ASICs), and field-programmable gate arrays (FPGAs).

[0180] In various implementations, a processor or control unit can be associated with one or more storage media, such as volatile and non-volatile computer memories including RAM, PROM, EPROM, and EEPROM. The storage media may be encoded with one or more programs that perform functions required when executed on one or more processors and / or control units. The various storage media may be fixed within the processor or control unit, or they may be transportable so that one or more programs stored therein can be loaded into the processor or control unit.

[0181] In carrying out the claimed invention, a person skilled in the art can understand and implement variations of the disclosed embodiments by examining the drawings, this disclosure, and the appended claims. In the claims, the word “equipment” does not exclude other elements or steps, and singular elements do not exclude plural elements.

[0182] A single processor or other unit may satisfy the functions of some of the matters described in the claims.

[0183] The mere fact that certain techniques are described in different dependent claims does not indicate that combinations of these techniques cannot be used advantageously.

[0184] Computer programs may be stored / distributed on suitable media such as optical storage media or solid-state media supplied together with or as part of other hardware, or they may be distributed in other forms, for example, via the Internet or other wired or wireless telecommunications systems.

[0185] It should be noted that when the term "adapted to" is used in the claims or description, it is intended to be equivalent to the term "configured to".

[0186] No reference numeral in a claim should be construed as limiting its scope. [Explanation of symbols]

[0187] 10 Shaving Units 100 Electric Shavers 12 hair cutting units 14 Lighting Modules 18 Lighting module housing 20 Lighting Elements 22 Support member 23 Contact pins 32 Cavity 34 Lighting module upper wall 36 Light-emitting surface 38 PCB 40 potting material 41a Potting layer 41b Further potting layer 42 First main surface of PCB 44 Second main surface of the PCB 46 Edge surface of PCB 50 Housing side wall 54 Skin contact surfaces 56 Opening 62 IR or NIR illumination elements 64 Visible Light Lighting Elements 72 Inner surface of the upper wall 110 Shaver body 120 External cutting member 122 Hair entry opening 86 Control device 310 Initial heating stage 320 Operation Stages 334 PI control member 350 Temperature Sensor 412 Light guiding component 416 Light attenuation element 420 Regions close to the exit surface 422 Virtual projection 424 Major regions of the exit surface 440 Light guide member 450 Layer of light-attenuating material 460 Light Guide Sheets 470 Opaque ink layer 472 Optically transparent retaining sheet 480 Light guide / light reflector 510 Central group of lighting elements 512 Central IR or NIR illumination element 516 Central Visible Lighting Element 520a First peripheral group 520b Second peripheral group 520c Third peripheral group 522 Peripheral IR / NIR illumination elements 524 Peripheral visible light illumination element 530 First part of the light guide member 532 Second part of the light guide member 534 Third part of the light guide member

Claims

1. One or more hair cutting units, A lighting module comprising a lighting module housing that accommodates one or more lighting elements, A shaving unit for an electric shaver, comprising one or more hair cutting units and a support member for supporting the lighting module, The lighting module housing has a cavity, the lighting element is disposed within the cavity, and the cavity is covered by the upper wall of the lighting module housing on the skin-facing side of the lighting module housing. The upper wall of the lighting module housing is made of an optically transparent material and has a skin-facing light-emitting surface, and during the operation of the shaving unit, the light generated by the lighting element is exposed to the skin through the skin-facing light-emitting surface, and the skin-facing light-emitting surface is positioned to be in contact with the skin during the operation of the shaving unit. The lighting module comprises a PCB located within the cavity, and the lighting element is mounted on a first main surface of the PCB facing the upper wall of the lighting module housing such that the lighting element is optically connected to the skin-facing light-emitting surface during the operation of the shaving unit. The cavity includes an optically transparent potting material that seals the lighting element by covering the first main surface of the PCB, the cavity extending between the first main surface of the PCB and the upper wall of the lighting module housing, the optically transparent potting material further covers the second main surface of the PCB on the opposite side of the first main surface, so that the optically transparent potting material completely seals the PCB. Shaving unit.

2. The shaving unit according to claim 1, wherein the potting material extends seamlessly from the first main surface of the PCB to the upper wall of the lighting module housing.

3. The shaving unit according to claim 1, wherein the potting material at least partially covers the edge surface of the PCB extending between the first main surface and the second main surface.

4. The shaving unit according to any one of claims 1 to 3, wherein the lighting module housing comprises a side wall that is combined with the upper wall of the lighting module housing to define the cavity.

5. The shaving unit according to any one of claims 1 to 3, wherein each of the one or more lighting elements is an LED.

6. The shaving unit according to any one of claims 1 to 3, wherein each of the one or more illumination elements comprises an infrared or near-infrared illumination element.

7. The shaving unit according to claim 6, wherein the optically transparent material and / or the optically transparent potting material has a peak light transmittance in the range of 800 to 1050 nm.

8. The shaving unit according to claim 5, wherein each of the one or more LEDs is configured to emit light having wavelengths mainly in the range of 525 to 575 nm, 675 to 725 nm, or 775 to 825 nm.

9. The shaving unit according to any one of claims 1 to 3, wherein the lighting module housing is entirely made of the optically transparent material.

10. The shaving unit according to claim 9, wherein the lighting module housing is an integrally molded injection-molded polymer structure.

11. The shaving unit according to any one of claims 1 to 3, wherein the lighting module housing comprises a skin contact surface positioned to contact the skin during the operation of the shaving unit, the skin contact surface defining one or more openings in which one of the one or more hair cutting units is disposed, such that each of the one or more hair cutting units is completely surrounded by the skin contact surface, and the skin-facing light-emitting surface is part of the skin contact surface.

12. The shaving unit according to claim 11, wherein the shaving unit comprises at least two hair cutting units, and the skin-facing light-emitting surface of the illumination module extends at least within the region between the hair cutting units on the skin-contact surface.

13. The shaving unit according to any one of claims 1 to 3, wherein the potting material comprises an adhesive resin, such as a silicone resin or an epoxy resin.

14. The shaving unit according to any one of claims 1 to 3, wherein the potting material comprises an optically transparent base potting material and ceramic particles embedded in the base potting material, the ceramic particles having a size smaller than the wavelength of light emitted by the one or more lighting elements of the lighting module.

15. The shaving unit according to any one of claims 1 to 3, wherein the lighting module comprises one or more electrical connection members that are electrically connected to the PCB and extend from the second main surface of the PCB through the potting material to the outside.

16. A shaving unit according to any one of claims 1 to 3, An electric shaver comprising a main body connected to the shaving unit for driving the one or more hair cutting units, Each of the one or more hair cutting units of the shaving unit is An external cutting member having multiple hair entry openings, The system comprises an internal cutting member covered by the external cutting member and having a plurality of cutting elements that are movable relative to the external cutting member, Electric shaver.

17. A method for providing a shaving unit for an electric shaver, wherein the method is: A step of providing a lighting module housing, wherein the lighting module housing comprises an upper wall having a skin-facing light-emitting surface and a side wall that, in combination with the upper wall, defines a cavity of the lighting module housing, the upper wall having an inner surface facing into the cavity, and the step of providing, The steps of providing a lighting unit comprising a PCB and one or more lighting elements mounted on a first main surface of the PCB, The steps include: arranging a layer of optically transparent potting material on the inner surface of the upper wall; The steps include: installing the lighting unit on the layer of potting material in the cavity, with the first main surface of the PCB facing the upper wall, such that the potting material is applied to the first main surface of the PCB and all the lighting elements are sealed by the potting material; A step of providing a further layer of the potting material on the lighting unit so as to cover the second main surface of the PCB opposite to the first main surface, wherein the lighting unit is completely sealed by the potting material, The step of providing a lighting module includes the step of curing the potting material, The method further comprises the step of including the illumination module as part of the shaving unit such that, during the operation of the shaving unit, the skin-facing light-emitting surface comes into contact with the skin when the shaving unit is applied to the user's skin for shaving.

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