Shaving unit and electric shaver comprising the same

Abstract

A shaving unit and / or electric shaver having an illumination module for providing an optical heating function at a skin contacting surface of the shaving unit. At least one aspect of the invention relates to a two-phase control scheme for accelerating the temperature rise of the skin contacting surface by increasing the average optical power density during an initial duration.

Description

Technical Field

[0001] The present invention relates to a shaving unit for an electric shaver, and an electric shaver comprising the shaving unit. Background Art

[0002] The present invention belongs to the field of shavers, in particular electric shavers, which are designed to perform shaving actions, etc., wherein hair is cut at a position close to the skin. Typically, an electric shaver comprises a shaving unit in which one or more hair cutting units are arranged, wherein the shaving unit comprises a base member for supporting the one or more hair cutting units. A particularly common design of a shaving unit is to use three hair cutting units arranged in an equilateral triangle. In addition to the shaving units, the electric shaver also comprises a body. The body is typically shaped to be suitable for being held by a user of the shaver and can accommodate various components of the shaver, such as an electric motor.

[0003] Each hair cutting unit of the shaving unit comprises a combination of an inner cutting member and an outer cutting member, the outer cutting member being arranged to cover the inner cutting member, the outer cutting member being provided with a series of hair entry openings for allowing hair to pass through the outer cutting member to reach and encounter the inner cutting member during the shaving action. In a practical design, the outer cutting member is usually cup-shaped and has a substantially circular periphery, wherein the hair entry openings may be shaped like an elongated slit extending substantially radially relative to the central axis of the outer cutting member in one or more annular regions constituting one or more hair cutting tracks. Such an outer cutting member is particularly suitable for rotary electric shavers, i.e. electric shavers comprising at least one hair cutting unit, wherein the inner cutting member is arranged to rotate during operation.

[0004] The correct use of an electric shaver comprises placing the shaver in an active state, i.e. a state in which the internal cutting member of at least one hair cutting unit rotates, and moving the shaving unit on a part of the skin to be subjected to a shaving action. The external cutting member has a hair cutting track surface for contacting a part of the skin at the position of one or more hair cutting tracks during the hair cutting action. The hair cutting surface is present in the external cutting member at a position defining the hair entry opening. In a common design, the internal cutting member comprises a blade with a hair cutting edge. During the shaving action, the hair entering the hair entry opening is cut between the hair cutting surface and the hair cutting edge, and is therefore cut off at a position close to the skin.

[0005] CN 108714917A discloses an electric shaver comprising a shaving unit and a main body. The shaver is equipped with an infrared heating device, a battery and a switch which are electrically connected to each other. The reason for equipping an electric shaver with an infrared (or near-infrared) heating device such as known from CN 108714917A is the fact that exposure of the hair to infrared light helps to soften the hair. Generally, exposing the hair to infrared light during the shaving action improves the comfort experienced by the user. Moreover, by irritating the skin and causing a radiant appearance of the skin, infrared light can also stimulate blood circulation and have a beneficial effect on the skin.

[0006] Not only infrared light but also other light emissions can be used to generate the heating stimulus, including in the visible spectrum.

[0007] The lighting element requires some time to heat the shaving head to the optimum temperature for skin application. Increasing the power of the lighting element can increase the rate of temperature rise. However, this raises safety and comfort issues as the increased power may result in burns. An improvement to existing devices that could address this shortcoming would be valuable. Summary of the invention

[0008] The invention is defined by the claims.

[0009] According to one aspect of the present invention, there is provided an electric shaver comprising a shaving unit and a controller. The shaving unit comprises one or more hair cutting units. The shaving unit further comprises an illumination module, the illumination module comprising one or more illumination elements and a light output surface facing the skin, during operation of the shaving unit, light generated by the illumination elements is exposed to the skin via the light output surface, the light output surface is made of a light-transmitting material and is arranged to contact the skin during operation of the shaving unit. The illumination element is arranged to be in thermal contact with the light output surface via a thermally conductive path in the illumination module.

[0010] The shaving unit further comprises a support member supporting the one or more hair cutting units and the lighting module.

[0011] a controller of the shaving unit operatively coupled to the lighting module and adapted to control the lighting element in a driving scheme comprising: an initial heating phase, triggered upon activation of the lighting module, in which the lighting element is driven at an initial power setting;

[0012] The operating phase follows the initial heating phase. The maximum power value of the operating power setting is lower than the power value of the initial power setting. Optionally, the initial heating phase may target a predetermined temperature, wherein the lighting element is driven at the initial power setting until a predetermined temperature of the light output surface is reached.

[0013] Preferably, in the operating phase, the lighting element is driven at an operating power setting so that the temperature of the light output surface is controlled to maintain the predetermined temperature reached in the initial heating phase. In other words, the lighting element is controlled to adjust the temperature to maintain it as close to the predetermined temperature as possible.

[0014] The lighting module of the electric shaver according to the invention is capable of providing a heating effect to the skin during shaving. The heating effect is achieved optically and conductively. The optical heating of the skin is achieved by the optical absorption of the light generated by the lighting element and applied to the skin via the light output surface of the lighting module by the skin tissue. The conductive heating of the skin is achieved by the thermal contact of the skin with the light output surface of the lighting module, which is in thermal contact with the lighting element. Therefore, due to the limited electro-optical energy conversion efficiency of the lighting element, the conductive heating of the skin is achieved in particular by the heat dissipated by the lighting element. This combined optical and conductive heating of the skin is very effective.

[0015] The present invention provides an initial heating phase that serves as a temporary "boost" mode for more quickly heating the light output surface of the lighting module using an initial power setting that is higher than the maximum power value of the operating power setting during an operating phase following the initial phase. Although the maximum power value of the operating phase is selected so that it is comfortable and safe to use throughout the long-term use of the shaver during the shaving process, the initial heating phase allows the use of power settings that are higher than the safety limit for long-term use in order to more quickly heat the light output surface of the lighting module. Once the boost mode is completed, the power level is reduced. This can be indicated to the user, for example, by a changing visual indicator light pattern or an audible sound, and the shaver can then be used normally, for example with the light output surface at an optimal temperature. This avoids maintaining a higher power throughout the operation, thereby avoiding safety and comfort issues, such as skin burns.

[0016] The targeted predetermined temperature of the initial heating phase is preferably in the range from 40°C to 50°C.

[0017] Since the light output surface contacts the skin during use, the temperature range targets a temperature within the user's comfort tolerance. For example, normal facial temperature is about 36°C (where this may vary depending on environmental conditions). The average human perception sensitivity is about 2°C. Therefore, a perceptible warming action preferably targets a temperature above this perception threshold, and where, to avoid overheating (and burns), the optimal range may be between 40°C and 50°C.

[0018] In some embodiments, the predetermined temperature may be in the range from 41.8°C to 42.2°C, in the range from 44.8°C to 45.2°C, or in the range from 47.8°C to 48.2°C.

[0019] It may be advantageous to provide an electric shaver with an input member configured to enable a user of the electric shaver to select a predetermined temperature.

[0020] In some embodiments, one or more lighting elements may include one or more LEDs.

[0021] In some embodiments, one or more lighting elements may include infrared (IR) or near infrared (NIR) lighting elements.

[0022] The optical power density of the lighting elements at the light output surface may need to be configured to maximize warming efficiency while mitigating the risk of discomfort or skin damage. In some embodiments, the lighting module may be configured such that the light beam of at least one of the lighting elements has the highest average optical power density at the light output surface during the initial heating phase compared to the other lighting elements, and wherein the power value of the initial power setting is such that the highest average optical power density is between 325 mW / cm 2 and 360mW / cm 2 between.

[0023] This embodiment is based on the recognition that the light beam of at least one of the lighting elements will have the highest average light power density at the light output surface of the lighting module. In this context, the average light power density of the light beam is measured over the cross section of the light beam at the location of the light output surface. The highest average light power density should not exceed 360 mW / cm 2 value, and should preferably be 325mW / cm 2 and 360mW / cm 2 These values ​​are chosen so that, in a worst-case usage scenario where a user holds the electric shaver in a stationary position on the skin for a predefined period of time, the total light energy density applied to the skin by the lighting module at the position of the light beam of said at least one of the lighting elements will not exceed the skin safety limits defined by the IEC / EN 62471 standard "Photobiological safety of lamps and lamp systems". In particular, the predefined period of time is 10 seconds. This is to maximize the warming effect (which depends on the light power density) during the initial power period while not exceeding the safety limits.

[0024] In some embodiments, activation of the lighting module may be triggered by activation of one or more hair cutting units, for example by the controller upon said activation, or automatically due to a wiring arrangement between the cutting units and the lighting module.

[0025] In some embodiments, the electric shaver may comprise a further input member configured to enable a user of the electric shaver to activate the illumination module independently of activation of the one or more hair cutting units.

[0026] In some embodiments, the duration of the heating phase may be set to be no greater than 20 seconds, and preferably no greater than 10 seconds.

[0027] In one advantageous set of embodiments, the electric shaver may further comprise a temperature sensor, and wherein the controller is configured to control the power setting of the operating phase in dependence on the output from the temperature sensor during the operating phase. In other words, the controller actively adjusts the power level of the lighting element in a feedback loop with the temperature sensor so as to target the maintenance of a specific temperature (increasing the power in response to a drop in temperature, decreasing the power in response to a rise in temperature). In other words, the operating phase is controlled as a steady-state phase with respect to temperature, wherein the lighting power is adjusted to maintain a constant temperature range. This is in contrast to a heating phase where the power is set to achieve a rapid increase in temperature.

[0028] The temperature sensor is preferably located in the shaving unit.

[0029] In some embodiments, the controller may be configured to control the duration of the initial heating phase and, during the operating phase, to control the temperature of the light output surface based on output from the temperature sensor.

[0030] In some examples, the controller includes a feedback control loop including a temperature sensor and a proportional-integral (PI) control component.

[0031] In some embodiments, the lighting module includes a PCB, and wherein the lighting element is mounted to a first major surface of the PCB facing the light output surface, such that the lighting element is in optical communication with the light output surface during operation of the lighting module. The above-mentioned temperature sensor may also be mounted on the major surface of the PCB, and may be mounted thereon at a position adjacent to one of the lighting elements. In other words, the temperature sensor is positioned next to at least one of the lighting elements to maximize thermal coupling between the two.

[0032] The aforementioned thermally conductive path (from the lighting element to the light output surface) may include (ie, be facilitated by) a light-transmissive potting material covering a major surface of the PCB so as to encapsulate the lighting element and the temperature sensor.

[0033] For example, in some embodiments, the lighting module has a cavity covered by a light-transmitting upper wall of the lighting module including a light output surface. The PCB can be arranged in the cavity, and wherein the potting material extends between the main surface of the PCB and the upper wall of the lighting module.

[0034] The electric shaver may include a shaver body coupled to a shaving unit and include an electric motor for driving one or more hair cutting units of the shaving unit. The one or more hair cutting units of the shaving unit may each include an external cutting member having a plurality of hair entry openings and an internal cutting member having a plurality of cutting elements, the cutting elements being covered by the external cutting member and being movable relative to the external cutting member. The controller may be housed in the shaver body. In some embodiments, the shaving unit is a detachable attachment of the shaver body.

[0035] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] For a better understanding of the invention, and in order to more clearly show how the invention may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

[0037] Figure 1 showing a perspective view of the exterior of an exemplary electric shaver according to one or more embodiments of the present invention;

[0038] Fig. 2 shows a perspective cross-sectional view of a shaving unit according to an aspect of the invention;

[0039] FIG3 shows a cross-sectional view through a lighting module of a shaving unit according to one or more embodiments of the present invention;

[0040] Figure 4 A partial cross-sectional view of the interior of a lighting module housing according to one or more embodiments of the present invention is shown;

[0041] Figure 5 shows another cross-sectional view through a lighting module according to one or more embodiments of the present invention;

[0042] FIG6 illustrates stages in an example method of manufacturing a lighting module according to one or more embodiments of the present invention;

[0043] Figure 7 shows an example of first and second operating stages of a lighting module according to an aspect of the present invention;

[0044] Figure 8 Skin temperature profiles corresponding to discomfort and injury of the subject are shown;

[0045] Fig. 9 illustrates an exemplary optical output profile provided by an exemplary spatial arrangement of lighting elements in a lighting module according to at least one embodiment of the present invention;

[0046] Fig.10An exemplary driver circuit for controlling a lighting module using sensor feedback from a temperature sensor is shown;

[0047] Fig.11 shows undesirable visible light output of an illumination module in an electric shaver provided without an optical device for modifying the visible light profile;

[0048] Fig.12 An example illumination module in an electric shaver without an optical device for modifying the visible light profile is shown;

[0049] Figure 13-Figure 15 An exemplary illumination module in a shaving unit according to the invention is shown in cross section, having optical means for providing light guidance of a visible light output;

[0050] Fig.16 shows a modified visible light profile provided at a light output surface of a lighting module according to one or more embodiments of the present invention;

[0051] Fig.17 A perspective view showing a portion of an optical device in a lighting module according to one or more embodiments of the present invention;

[0052] Fig.18 shows an exploded view of an example shaving unit comprising an optical device according to the invention;

[0053] Fig.19 Another embodiment of a lighting module is shown, the lighting module having an optical device integrally formed with a housing of the lighting module;

[0054] Fig. 20 Shown by Fig.19 Example visible light output provided by the lighting module;

[0055] Fig.21 shows a PCB portion of an example lighting module according to the present invention;

[0056] Fig. 22 Shows Fig.21 positioning of lighting elements of the lighting module relative to a light output surface of the lighting module; and

[0057] Fig.23 Shows Fig.21 An example light guide member of a lighting module. DETAILED DESCRIPTION

[0058] The present invention will be described with reference to the accompanying drawings.

[0059] It should be understood that the detailed description and specific examples, although indicating exemplary embodiments of the device, system and method, 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 device, system and method of the present invention will become better understood from the following description, the appended claims and the accompanying drawings. It should be understood that the drawings are only schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to represent the same or similar components.

[0060] The present disclosure generally relates to a shaving unit and / or electric shaver having an illumination module for providing an optical heating function at a skin contact surface of the shaving unit. At least one aspect of the present invention relates to a two-phase control scheme for accelerating the temperature rise of the skin contact surface by increasing the average optical power density during an initial duration.

[0061] Figure 1 A first perspective view of the visible exterior of an example shaving unit 10 for an electric shaver 100 according to at least one embodiment of the present invention is shown. In the example shown, the electric shaver 100 is of a rotary type (although this is not required) and comprises a main body 110 for being held by a user of the shaver 100 and a shaving unit 10 for contacting a skin portion to be subjected to a shaving action. The main body 110 of the shaver 100 is also commonly referred to as a handle, and the shaving unit 10 of the shaver 100 is also commonly referred to as a shaving head. For various reasons, such as the need to maintain and / or clean the shaving unit 10, the need to replace the shaving unit 10 with another type of functional unit, etc., it is practical if the shaving unit 10 is detachably or hingedly mounted to the main body 110. The shaving unit 10 comprises a number of hair cutting units 12, three in the example shown. In the example shown, the hair cutting units 12 are arranged in a generally triangular form. When the electric shaver 100 is used to subject a portion of the skin to a shaving action, the actual process of severing the hair protruding from the portion of the skin takes place at the location of the hair cutting unit 12. In order to support the hair cutting unit 12, the shaving unit 10 comprises a support member 22, which in this example serves as a base member of the shaving unit 10.

[0062] Hair cutting unit 12 comprises the combination of outer cutting member 120 and inner cutting member (not shown) of cup-shaped design in general, and this inner cutting member is equipped with at least one hair cutting unit and is at least partially contained in the inside of inner cutting member.Outer cutting member 120 has hair entry opening 122 in annular cutting track surface.During shaving action, hair extending through hair entry opening 122 and protruding into outer cutting member 120 inside is just cut off once encountering the hair cutting element of inner cutting member.When inner cutting member is actuated to rotate and a part of skin is actually contacted by outer cutting member 120 at the position of cutting track surface, shaving action as described above can be performed.The activation of inner cutting member can be carried out in a known manner by the drive mechanism of shaver 100 comprising electric motor.Main body 110 can hold drive mechanism, optionally hold local power source (such as battery) together. When the combination of the external cutting member 120 and the internal cutting member moves over the portion of the skin while the internal cutting member is driven to rotate, hair protruding from the portion of the skin is captured in the hair entry opening 122 of the external cutting member 120 and cut off at that location.

[0063] It should be noted that the present invention also covers electric shavers and shaving units having one or more different types of hair cutting units as described above. In particular, the present invention also covers electric shavers and shaving units having the following hair cutting units, which have an internal cutting member arranged to reciprocate linearly relative to the external cutting member.

[0064] The upper surface of the shaving unit 10 comprises a skin contact surface 54, at least a portion of which is formed by or forms a light output surface 36 of a lighting module integrated inside the shaving unit 100, as will be further described below.

[0065] It should be noted that the foregoing general information regarding the electric shaver 100 according to the first embodiment of the present invention (which will be described below) is compatible with all subsequently described embodiments of the present invention (although not necessarily required).

[0066] FIG. 2 shows an exploded view of an example shaving unit 10 according to one or more embodiments. In particular, Figure 2A A close-up, partially cut-away internal view of the shaving unit 10 is shown, and Figure 2B A wide exploded view of the shaving unit is shown. Fig. 3 shows a cross section through the shaving unit 10 along the line A shown in Fig. 3 . Figure 4 An underside interior view of a portion of the shaving unit 10 is shown. Figure 5 Shown along Figure 5Line B is shown through a cross-sectional view of the shaving unit 10 .

[0067] The shaving unit 10 comprises a lighting module 14, which comprises a lighting module housing 18 accommodating one or more lighting elements 20. In this example, the lighting module housing 18 is arranged on a support member 22 of the shaving unit 10 and forms a part of the shaving unit housing. In particular, the lighting module housing 18 forms an upper part of the shaver unit housing, and the support member 22 is used to support the one or more hair cutting units 12 and the lighting module 14. The lighting module housing 18 defines one or more openings 56, in which a corresponding one of the one or more hair cutting units 12 in the shaving unit 10 is arranged. However, such formation is not required. For example, the lighting module can be a completely separate structural unit integrated in a separate housing of the shaving unit; the described design confers additional structural efficiency, but is not necessary for the concept of the present invention.

[0068] The lighting module 14 further comprises electrical connection pins 23 extending downwardly from the lighting module 14 for electrically contacting complementary electrical contacts in the body 110 for providing an electrical connection between the lighting module 14 and the shaver body 110 in an assembled configuration.

[0069] The lighting module housing 18 defines an internal cavity 32, and the lighting element 20 is arranged in the cavity 32. The cavity 32 is covered by an upper wall 34 of the lighting module housing on the skin-facing side of the lighting module housing 18. The upper wall incorporates a light output surface 36 facing the skin, via which light generated by the lighting element 20 is exposed to the skin during operation of the shaving unit. The upper wall 34 is made of a light-transmitting material, wherein the light-transmitting material provides the light output surface. In other examples, the upper wall 34 can incorporate the light output surface as a sub-area within a wider wall area, so that the light output surface forms a light output window through the upper wall.

[0070] In the illustrated example, the lighting module housing 18 also includes side walls 50 a , 50 b that define the cavity 32 in conjunction with the upper wall 34 of the lighting module housing 18 .

[0071] In the example shown, the upper wall 34 of the lighting module housing 18 at least partially defines a skin contact surface 54 for the shaving unit 10, and the aforementioned light output surface 36 incorporated in the upper wall 34 is arranged for contacting the skin during operation of the shaving unit.

[0072] The lighting module housing 18 can be a one-piece structure in some examples. It can be an injection molded part. It can be formed from plastic.

[0073] The lighting module 14 includes a carrier, such as a printed circuit board (PCB) 38, arranged in the cavity 32, wherein the lighting element 20 is mounted to a first main surface 42 of the PCB facing the upper wall 34 of the lighting module housing 18 (best shown in Figure 3), so that the lighting element 20 is optically connected to the light output surface 36 during operation of the shaving unit 10.

[0074] The cavity 32 contains a light-transmissive potting material 40 (best shown in FIG. 3 ) covering a first major surface 42 of the PCB, thereby encapsulating the lighting element 20. The potting material 40 extends between the first major surface 42 of the PCB 38 and the upper wall 34 of the lighting module housing 18. The potting material 40 also covers a second major surface 44 of the PCB 38 opposite the first major surface 42 (i.e., the reverse side or underside of the PCB 38). The potting material 40 thus encapsulates the PCB 38 on all major sides. The potting material provides a thermally conductive path in the lighting module 14 between the lighting element 20 and the light output surface 36, thereby placing the lighting element 20 in thermally conductive contact with the light output surface 36. The potting material 40 also provides a waterproofing function, as further explained below.

[0075] The lighting element 20 is adapted to provide a skin heating effect at the light output surface 36 of the lighting module housing 18 when in contact with the skin during operation. That is, when the lighting element 20 of the lighting module 14 is activated during the shaving action, a thermal stimulation of the skin is achieved, which can lead to an improvement in skin condition or appearance and / or an improvement in shaving comfort. In the example shown, this is achieved by including one or more infrared (IR) or near infrared (NIR) lighting elements 62 in the lighting element 20. These provide a light output having a main frequency component in the IR or NIR band of the electromagnetic (EM) spectrum. The IR or NIR band has a particularly good penetration depth into the skin. The light-transmitting material and / or the potting material 40 of the upper wall 34 of the lighting module housing 18 can have an optical transmittance distribution, wherein at least one peak in the optical transmittance distribution is in the light wavelength range of 800nm-1050nm to maximize the light coupling from the IR or NIR lighting element 20, 62 to the light output surface 36.

[0076] In addition to the optically induced skin heating effect of the IR or NIR lighting element 20, 62 caused by the optical absorption of the IR or NIR light emitted by the lighting element 20, 62 by the skin tissue, the lighting element 20 also provides a conductively induced skin heating effect caused by the thermally conductive path between the lighting element 20 and the light output surface 36 provided by the potting material 40. As a result of the thermally conductive path, the light output surface 36 is heated by thermal energy, which is dissipated by the lighting element 20 due to the limited electrical-to-optical conversion efficiency of the lighting element 20. Therefore, during shaving, the skin is also conductively heated due to the thermally conductive contact of the skin with the light output surface 36. The combined optically induced and conductively induced skin heating effects provide a high skin heating efficiency of the lighting module 14 in the shaving unit 10.

[0077] It is not necessary that the lighting element 20 include an IR or NIR lighting element, as light-induced heating is feasible using other parts of the EM spectrum, such as using a visible light lighting element. In some cases, an optical component such as a lens can be used in conjunction with a visible light lighting element to focus or concentrate the light output, thereby increasing the thermal power of the light at the light output surface.

[0078] Furthermore, while at least one function of the lighting module is to provide a heating effect, the light emission may additionally provide other beneficial effects to the skin tissue. For example, blue visible light is known to be beneficial for acne treatment, and red visible light is known to be beneficial for stimulating wound healing and treating skin inflammation.

[0079] In the example shown, the set of lighting elements 20 includes one or more visible light lighting elements 64 in addition to the IR or NIR lighting elements 62 for providing a visible light indication of the activation of the IR or NIR lighting elements. They can be configured to be active when the IR or NIR lighting elements are active, either by active control of the controller, or by electrically supplying them by a parallel wiring arrangement with the IR / NIR lighting elements 62 in the circuit arrangement. However, the visible light lighting elements may be omitted in other examples.

[0080] When a visible light lighting element 64 is provided, the light-transmitting material of the upper wall 34 of the lighting module housing 18 and / or the potting material 40 may have at least one additional peak in light transmittance within the light wavelength range of 450nm-700nm to maximize the light coupling from the visible light lighting element 64 to the light output surface 36.

[0081] In some examples, each lighting element 20 of the one or more lighting elements may include an LED.

[0082] The lighting module 14 includes one or more electrical connection members 23 (connection pins) that are electrically connected to the PCB 38 and extend from the second major surface 44 of the PCB, through the potting material 40 and out from the potting material 40 .

[0083] With respect to the potting material 40, this serves the dual function of inhibiting the ingress of moisture or other contaminants into the cavity 32 (e.g. dirt or dust), and also serves the function of providing thermal coupling from the lighting element 20 to the light output surface 36 (and therefore to the skin surface during normal use of the electric shaver 100).

[0084] Preferably, the potting material 40 extends uninterruptedly from the first major surface 42 of the PCB 38 to the upper wall 34 of the lighting module housing 18. In other words, it defines at least one continuous solid material path from the first major 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 elements 20 on the first major surface 42 of the PCB 38 to the light output surface 36 in the upper wall 34 of the lighting module housing 18, thereby optimizing heat conduction.

[0085] Preferably, the lighting module 14 should be manufactured so that air bubbles in the potting material 40 are minimized or even eliminated, because air bubbles reduce the overall thermal conductivity of the thermal path from the PCB first major surface 42 to the light output surface 36. Air bubbles also adversely affect the uniformity of temperature distribution. A particularly advantageous manufacturing method will be outlined later in this disclosure.

[0086] Preferably, the potting material 40 extends between the PCB 38 and the light output surface 36 as a continuous, monolithic structure, ie without interruptions. At a minimum, it should include at least one continuous solid path from the PCB 38 to the light output surface 36.

[0087] During assembly of the lighting module 14 , the PCB 38 should preferably be completely wetted by the potting material 40 on both major surfaces 42 , 44 thereof.

[0088] To effectively prevent moisture ingress, there should be a chemical bond or adhesion between the potting material 40 and the first and second major surfaces 42, 44 of the PCB 38. There should also be a chemical bond between the potting material 40 and the inner surface of the cavity 32 (i.e., the inner surface of the upper wall 34 and the side walls 50a, 50b).

[0089] In order to effectively prevent water, preferably, there should also be a chemical bond or adhesion between the potting material 40 and the electrical contact pins 23. This helps prevent water from entering through the surface of the electrical contact pins 23.

[0090] Preferably, the potting material 40 at least partially covers an edge surface 46 of the PCB 38 extending between the first and second major surfaces 42 , 44 .

[0091] Suitable materials for the potting material 40 may include, for example, glue resins such as silicone or epoxy resins. However, any encapsulation or filling material may generally be used. Preferably, the material is a material that exhibits the following properties within the functional temperature range of the lighting module 14: (a) does not change phase; (b) does not (substantially) change its mechanical, thermal or optical properties; (c) does not show discoloration. The functional temperature range may be, for example, between -10°C and 100°C, with the actual target operating temperature typically being about 40°C-60°C. The wider temperature range allows for variations in environmental conditions, for example, the shaver being left outside in a cold environment, or the shaver being left in a hot car in the sun.

[0092] Regarding the optical function of the lighting module 14, optionally, and as shown in FIG. 2- Figure 4 As shown, the lighting module may also include an optical device for generating a visible light output provided by the optional visible light lighting element 64 at the light output surface 36. In this example, this includes a light guide device 412, which is configured to guide the visible light generated by the visible light lighting element 64 to at least one area of ​​the light output surface 36 of the lighting module 14. The light guide device 412 may include a light guide sheet or film disposed on or above the first main surface 42 (upper surface) of the PCB 38. It may be adhered to the PCB 38 with an adhesive layer. It may be a light guide sticker. In some examples, this may guide light in a direction having a main direction component parallel to the light output surface 36. Optionally, a light attenuation element may also be provided for suppressing or attenuating a direct light path from each visible light lighting element 64 to the light output surface 36. Each light attenuation element may be facilitated by a light attenuation layer, which, for example, includes a light attenuation mask layer deposited on an optically transparent carrier layer, which is disposed on top of the light guide device. These features will be described in more detail later in this disclosure.

[0093] With respect to the optical functionality of the lighting module 14, in some examples, the lighting module housing 18 may be made entirely of the previously mentioned optically transmissive material (the material forming the light output surface 36). It may be optically translucent, e.g., diffusive, to prevent the interior of the cavity 32 of the lighting module 14 from being directly visible from the visible surface of the shaving unit 10. This allows the entire body of the lighting module housing 18 to provide the functionality of coupling light from the lighting elements 20 to the light output surface 36 and the skin contact surface 54 of the shaving unit 10. The lighting module housing 18 may optionally be a one-piece, injection molded polymer structure.

[0094] As previously mentioned, the lighting module housing 18 in this example includes a skin contact surface 54, which is arranged to contact the skin during operation of the shaving unit 10. The light output surface 36 forms at least a part of the skin contact surface 54. The skin contact surface 54 defines one or more openings 56, and a corresponding one of the one or more hair cutting units 12 of the shaving unit 10 (when assembled) is arranged in the opening 56. In the example shown, each of the one or more hair cutting units 12 is completely surrounded by the skin contact surface 54, although this is not required (for example, in a foil-razor structure, the skin contact surface may extend around only a subset of the sides of each elongated hair cutting unit).

[0095] As shown in FIG. 2 , the light output surface 36 of the lighting module 14 extends at least in the region of the skin contact surface 54 between each of the plurality of hair cutting units 12 .

[0096] In Figure 2- Figure 5 In the example of FIG. 4 , all lighting elements 20 are mounted to the first major surface 42 of the PCB, which faces the light output surface 36. However, this is not required. In some embodiments, one or more lighting elements 20, in particular one or more visible light lighting elements, can be mounted to the second major surface 44 (i.e., the surface on the lower side) of the PCB.

[0097] Figure 4 A bottom side view of a PCB 38 of a lighting module according to this example is shown. Figure 4 A partial cross-sectional view is shown showing components on second major surface 44 (i.e., underside surface) of PCB 38. In this example, a plurality of visible light lighting elements 64 are disposed on the second major surface of the PCB. These lighting elements may be provided in addition to the visible light lighting elements on first major surface 42 of PCB 38 described above, or in lieu of the visible light lighting elements on first major surface 42 of the PCB.

[0098] In some embodiments, at least one temperature sensor 350, such as a thermistor (see Figure 5 ). This is preferably located adjacent to at least one of the IR or NIR lighting elements 62. The temperature sensor 350 may be used by the controller to adjust the power level of the IR or NIR lighting element 62 for adjusting the temperature at the light output surface 36. However, the temperature sensor 350 is optional and may be omitted.

[0099] The lighting module may include one or more additional electrical components mounted to the PCB 38, such as one or more resistors 66, such as Figure 5 shown.

[0100] Figure 6A-6D Schematically shows the formation for FIG2- Figure 5 The steps of at least part of a suitable method for manufacturing the illumination module 14 of the shaving unit 10 are shown. Figure 6A-6D The steps shown are for assembling at least a portion of the lighting module 14 .

[0101] The method includes: Fig. 6A ) provides 210 a lighting module housing 18 including an upper wall 34 and side walls 50a, 50b, the upper wall 34 including a light output surface 36, and the side walls 50a, 50b and the upper wall 34 combine to define a cavity 32 of the lighting module housing 18. The upper wall 34 has an inner surface 72 facing the cavity 32.

[0102] The method also includes ( Figure 6A-6D In a step not explicitly shown in the figure, a lighting unit is provided that includes a PCB 38 and one or more lighting elements 20 mounted to the first major surface 42 of the PCB 38. The lighting elements 20 may include IR or NIR lighting elements 62 and / or visible light lighting elements 64. The lighting unit may also include an optical device, such as a light guide 412 disposed on the first major surface 42 of the PCB 38.

[0103] The method also includes ( Figure 6B ) A layer 41a of a light-transmissive potting material 40 is disposed 230 on the inner surface 72 of the upper wall 34. The inner surface 72 is preferably completely wetted by the potting material layer.

[0104] The method also includes placing 240 the aforementioned lighting unit including the PCB 38 and the lighting elements 62, 64 onto the layer 41a of the potting material 40 in the cavity 32, wherein the first main surface 42 of the PCB 38 faces the upper wall 34, so that the first main surface 42 of the PCB is wetted by the potting material 40 and the lighting elements 62, 64 are each encapsulated by the potting material.

[0105] The method further comprises providing 250 a further layer 41 b of the potting material 40 on the lighting unit to cover a second major surface 44 of the PCB 38 opposite to the first major surface 42, whereby the lighting unit is completely encapsulated by the potting material on the first and second major surfaces 42, 44 of the PCB 38. The potting material also preferably covers the side edges 46 a, 46 b of the PCB 38.

[0106] The method also includes providing a potting material.

[0107] The result of this method is a PCB 38 carrying thereon lighting elements 62, 64 integrated in a lighting module housing 18 which is sealed and wetted on all sides by a potting material 40. The potting material has a chemical bond to all parts with which it comes in contact.

[0108] The method further comprises the step of including the lighting module 14 as part of the shaving unit 10, so that during operation of the shaving unit, when the shaving unit is applied to the skin for shaving, the light output surface 36 is in contact with the skin of the user. This step can be achieved by assembling the lighting module 14 on the support member 22 of the shaving unit 10 during a subsequent manufacturing process of the shaving unit 10.

[0109] The setting step may be performed as a single step after both layers 41a, 41b of potting material have been deposited, or a first setting step may be performed after depositing the first layer 41a and positioning the lighting unit, and then a second setting step may be performed after depositing the second layer 41b on the lighting unit.

[0110] The above-described method provides particularly effective encapsulation and also minimizes bubble formation in the potting material layer to achieve optimal thermal conductivity and temperature uniformity of the potting material.

[0111] Instead of depositing the potting material 40 in a two-layer deposition process, a single deeper potting material layer may be deposited in the cavity 32 and then the lighting unit immersed in the potting material. However, this may not be very practical, especially when performed in mass production.

[0112] Preferably, the potting material 40 is a material that provides an optical transmittance of at least 90% of light from the IR or NIR lighting element 62 to the exterior of the lighting module 14 (via the light output surface 36 ).

[0113] Optionally, the lighting module housing 18 may be formed from an optically transmissive material, wherein preferably the material provides an optical transmittance of at least 70% of light from the IR or NIR lighting element 62 to the exterior of the lighting module 14 .

[0114] Preferably, the potting material 40 and the lighting module housing 18 have a thermal conductivity of at least 0.2 W / mK.

[0115] Preferably, the specific heat capacity of the potting material 40 is at least 800 J / KgK.

[0116] Preferably, the specific heat capacity of the lighting module housing 18 is at least 1250 J / KgK.

[0117] Optionally, the operating temperature range of the IR or NIR LED may be between -10°C and 100°C.

[0118] Optionally, the operating temperature range of the potting material 40 may be between -10°C and 100°C.

[0119] Optionally, the operating temperature range of the lighting module housing 18 may be between -10°C and 80°C.

[0120] Preferably, the potting material 40 should be chemically resistive and should be robust to frequent temperature cycles in its material properties.

[0121] The electric shaver 100 also includes a controller (not shown) for controlling the lighting element 20. The controller may be housed in the shaver body 110. The controller may include at least one processor. The controller may be arranged to receive signals or receive data from one or more sensors (e.g., a temperature sensor) included on the PCB.

[0122] One aspect of the present invention is to provide a novel control scheme for the lighting element 20 to optimize the temperature regulation of the light output surface 36. The shaving unit 10 in the example described below can be the same as or similar to the shaving unit described above. In particular, all features of the above-described electric shaver 100 and shaving unit 10 are compatible with the embodiment group of the present invention described below, but some features can be omitted. For example, the above-mentioned potting material is not necessary.

[0123] According to one or more embodiments, an electric shaver 100 is provided, which includes a shaving unit 10 (e.g., as described above), and includes a controller that is operably coupled to the lighting module 14 and is suitable for controlling the lighting element 20 in a drive scheme that includes at least a first and a second phase. The controller can be housed in the shaver body 110. The drive scheme includes an initial heating phase triggered when the lighting module is activated, in which the lighting element 20 is driven at an initial power setting. The drive scheme also includes an operating phase after the initial heating phase, in which the lighting element 20 is driven at an operating power setting. The maximum power value of the operating power setting is lower than the power value of the initial power setting. The initial heating phase can target a predetermined target temperature of the light output surface 36. This can be done implicitly (blindly) by executing a predetermined power profile with a defined duration that is known or predicted to result in a target temperature. Alternatively, it can be done actively by using input from a temperature sensor as feedback to guide one or both of the power setting and the duration of the initial heating phase.

[0124] In some examples, during the operation phase, the temperature of the light output surface may be controlled to be maintained at a predetermined temperature by active control of the operating power setting. For example, this may utilize a temperature sensor to provide active feedback.

[0125] The initial heating phase has a higher (initial) power setting to quickly heat the light output surface 36 to the target temperature required for operation. This improves the convenience of the user who must wait for a short duration before using the shaver. However, this initial power setting may provide a light output at the light output surface 36 that, if maintained throughout the shaving session, exceeds the light output that may be comfortable or safe for the user. Therefore, the second (operation) phase reduces the (time-averaged) power setting so that the temperature can be maintained, but the light output is comfortable and safe for the user.

[0126] As a further illustration, and not intended to limit the scope of the present invention, Figure 7 An example of a first and second phase is schematically shown in the graph of This shows an initial heating phase (1) and a subsequent operating phase (3), separated in time by a brief intermediate transition phase (2) during which the power setting is reduced from the initial power setting to a lower operating power setting. Figure 7 The optical power density at the light output surface (line A; unit: mW / cm 2 ), and the temperature at the light output surface 36 during each mode (line B; unit: ° C.), both the optical power density and the temperature at the light output surface are functions of time (unit: seconds).

[0127] With respect to the temperatures that should be targeted during the initial heating phase 310 and the operating phase 320, these temperatures may vary as desired and are typically based on user desired comfort and safety thresholds. Figure 8 An exemplary summary of different applied skin temperature profiles (i.e., maximum skin temperature allowed as a function of contact time with the heat source) that cause discomfort and burns is provided. Line C corresponds to a full skin thickness burn. Line D corresponds to a partial skin thickness burn. Line E corresponds to discomfort.

[0128] In at least one set of preferred embodiments, the predetermined temperature targeted in the initial heating phase and the operation phase may be in the range from 40° C. to 50° C. More specifically, the predetermined temperature may be in the range from 41.8° C. to 42.2° C., in the range from 44.8° C. to 45.2° C., or in the range from 47.8° C. to 48.2° C. These temperature ranges are based on the following considerations.

[0129] Since the light output surface 36 contacts the skin during use, the temperature range targets a temperature within the comfort tolerance desired by the user. For example, normal facial temperature is about 36°C (where this may vary depending on environmental conditions). The average human perceptual sensitivity is about 2°C. Adding this 2°C yields 38°C so that the heating effect is perceptible. Furthermore, considering the maximum sensory benefit for the user, the temperature should be the maximum possible temperature within safety and comfort limits, and a suitable minimum boundary range may be between 42°C-43°C. This temperature has been found to be at a level that is still comfortable for the user and is effective in providing skin benefits.

[0130] The upper boundary temperature can be chosen based on perception and preference as well as compliance with safety standards. This suggests that the maximum value of the skin must not be higher than 48°C. See, for example, Figure 8 , it can be seen from line E that for extended contact times of 10 seconds or more, a temperature of 48°C is just below the minimum temperature that will cause user discomfort. Assuming the system has a temperature accuracy of 0.05°C, the upper temperature limit can be set to 47.95°C.

[0131] Since user preferences for target temperatures may vary, the electric shaver in some embodiments may include an input member configured to enable a user of the electric shaver to select a predetermined temperature. An upper limit may be set on a selectable temperature, such as 48°C in some examples, so that the user cannot exceed a safety limit. The input member is operably coupled to the aforementioned controller. There may be a plurality of predetermined temperature settings from which the user can select. Alternatively, the controller and input member may allow the user to freely select any target temperature within certain temperature boundaries.

[0132] As an illustrative example, a set of example predetermined temperature settings for a target (predetermined) temperature selectable using an input means may be as follows:

[0133]

[0134] Table 1

[0135] The initial heating phase 310 can be automatically triggered when the device is turned on. During the initial heating phase, the optical power remains fixed at a relatively high setting, and the temperature of the light output surface 36 rises rapidly. When the predetermined target temperature is reached, the controller moves to the operating phase 320. Temperature feedback can be used to change the light output in the operating phase 320 so as to maintain the predetermined target temperature stable (steady-state phase).

[0136] In order to accelerate the heating of the light output surface 36, the initial power setting during the initial heating phase 310 is set to a higher value than the maximum power used during the subsequent operation phase 320. By increasing the power, the optical power density at the light output surface 36 is increased, thereby increasing the rate of heat transfer to the light output surface 36. Accelerating heating must be balanced with the comfort and safety described above. Further in order to manage the maximum temperature determined as a target, it is preferred to manage the maximum optical power density provided by the lighting element 20 at the light output surface 36.

[0137] The objective in this regard may be to seek to limit the total light energy density (in J / cm2) delivered to any point on the user's skin over a continuous period of time during use of the device. 2 The total light energy density delivered to a user's tissue area in any continuous time window is the time-averaged light power density (W / cm2) delivered over the area (through the light output surface in contact with the area) 2 ) and the time length of the time window. Since the length of time that a user applies the light output surface to a single tissue point cannot be directly controlled, it is advantageous to control the maximum optical power density provided at the light output surface during the initial heating phase based on an assumed worst-case user scenario related to the time period that the user applies the light output surface to a single tissue area.

[0138] The optical power density on the light output surface may generally vary as a function of the position on the light output surface. According to one or more embodiments, the heating phase may be configured such that at a point or region of the light output surface where the optical power density has a maximum value during the initial heating phase, the maximum value of the optical power density is between 325 mW / cm 2 and 360mW / cm 2 between.

[0139] This is an assumed safety constraint based on a worst case user scenario in which the user applies the light output surface to a single fixed point on the user's tissue for 10 seconds. Studies have shown that in normal use of any shaver, 10 seconds is a typical upper limit for the amount of time a user will hold the shaver on any one point before moving on. It is therefore reasonable to assume a maximum exposure time of 10 seconds. Furthermore, this time limit can be implemented by making the duration of the initial heating phase 10 seconds (after which the operating phase triggers, reducing the optical power at the light output surface) such that it is impossible for the user to exceed an exposure time of 10 seconds at the initial power setting. If the maximum optical power density at any spatial point / area on the light output surface is at the upper end of the above range, i.e. 360mW / cm 2 and the user applies the light output surface to the same static point for a maximum of 10 seconds, this would correspond to 3.6 J / cm 2 The total delivered light energy density exposed to the tissue at the static point is 3.6 J / cm2. This ensures compliance with the standard safety regulations of IEC / EN 62471 "Photobiological safety of lamps and lamp systems", which require 3.6 J / cm2. 2 Maximum light exposure.

[0140] Of course, it should be noted that the above range of maximum optical power densities is merely an exemplary implementation and is not intended to limit the concepts of the present invention. For example, if different assumptions are made about the user's application time, and / or if the specification constraints are different, the range can be changed. For example, the user can be given instructions about the maximum length of time they should apply the shaver to any one point (e.g., 5 seconds or 2.5 seconds), and it is assumed that the user follows these instructions. An automatically generated feedback prompt (e.g., auditory or tactile) can be issued after any static hold of the device at a point for a predetermined length of time.

[0141] If this assumption is made, the maximum optical power density at the light output surface may increase to more than the above 360 ​​mW / cm 2 For example, if the continuous application time to the tissue is no longer than 5 seconds, the maximum time-averaged optical power density at the light output surface during the initial heating phase can be set as high as 600 mW / cm 2 If the assumed maximum exposure time is even shorter, at 2.5 seconds, the maximum optical power density can even further increase to 1 W / cm 2 The initial heating period may be set to have a length equal to these maximum time periods, although these time periods may not be long enough to achieve the desired target surface temperature.

[0142] It is a design choice, to the extent that the user is trusted not to exceed the expected maximum exposure time at one point. To balance this with safety, an assumed exposure time of 10 seconds (based on the user's natural behavior pattern) may be preferred. In this way, the temperature of the skin can be controlled to remain below a predefined maximum temperature (e.g. 48°C) and the light energy exposure can be kept at 3.6 J / cm 2 the following.

[0143] The lighting module may generally include a spatial arrangement of IR or NIR lighting elements 62, wherein the irradiance (optical power per unit area) provided at the light output surface is different for different lighting elements 62. The irradiance may differ in this regard due to different optical path lengths between different respective IR or NIR lighting elements 62 and the light output surface.

[0144] In view of the above, according to one or more embodiments, the lighting module can be configured so that the light beam of at least one of the IR or NIR lighting elements 62 has the highest average light power density at the light output surface during the initial heating stage compared with other IR or NIR lighting elements, wherein the power value of the initial power setting is such that the highest average light power density is between 325 mW / cm 2 and 360mW / cm 2 The average optical power density provided by the light beam of a given lighting element at the light output surface refers to the average value of the optical power density measured in the cross section of the light beam at the light output surface during the initial heating phase. It is assumed here that the light beams of different IR or NIR lighting elements do not overlap at the light output surface. Therefore, depending on their position in the lighting module 14, one or more of the IR or NIR lighting elements will provide the highest average optical power density at the light output surface. The initial power setting needs to be such that this highest average optical power density is between 325 mW / cm 2 and 360mW / cm 2 In embodiments where the lighting elements provide overlapping light beams at the light output surface, the initial power setting during the initial heating phase should, for example, be such that the highest light power density at any position on the light output window is within the above range of light power densities.

[0145] The optical power density provided by a given lighting element 62 will depend on the power of the source powering the lighting element, and also on the optical path length from the lighting element to the light output surface.

[0146] For example, refer to Fig. 9, which shows (left) an example positioning of the IR / NIR lighting elements 62 of an example shaving unit 10 relative to the light output surface 36. The lighting elements 62 are arranged in a plurality (in this case four) of spatial groups or clusters. Each group may contain at least one IR / NIR lighting element 62, but may contain more than one IR / NIR lighting element. The lighting 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. The radiation pattern of a typical IR / NIR LED lighting element 62 is shown in FIG. Fig. 9 (right) This shows that the typical maximum angular range of radiation is 60 degrees on each side of the vertical optical axis of the LED.

[0147] In view of this, it can be determined that the central group 510 of one or more IR / NIR lighting elements 62 has a larger irradiance area at the light output surface, has optimal contact with the skin, but has less than 300 mW / cm due to the greater distance between the IR / NIR lighting elements compared to the peripheral groups of IR / NIR lighting elements. 2 The larger distance between the central group 510 and the light output surface is due to the slight convex curvature of the lighting module housing 18, the apex of which coincides with the location of the central group of lighting elements.

[0148] In this example, in the area between the four groups of IR / NIR lighting elements 62 (the area between the blue circles), the skin contacting surface will receive substantially no irradiation from the IR / NIR lighting elements, and thus this area will only be exposed to conductive heating.

[0149] Control options for the lighting element 20 for implementing the initial heating phase 310 and the operating phase 320 will now be discussed in more detail.

[0150] Regarding the control of the lighting module 14, the activation of the lighting module 14 can be triggered by activating one or more hair cutting units 12. For example, the activation of the initial heating phase can be triggered by the activation of one or more hair cutting units (i.e., the electric shaver is turned on). This simultaneous activation can be achieved by the simultaneous control of the aforementioned controller of the electric shaver 100, or it can be automatically triggered due to the parallel wiring arrangement between the cutting unit 12 and the lighting module 14.

[0151] In addition to or in lieu of this control arrangement, the electric shaver 100 may include a further input member (e.g., a switch or other input device) configured to enable a user of the electric shaver to activate and / or deactivate the lighting module 14 independently of activation of one or more hair cutting units 12. This allows the user to choose to use the hair cutting function of the shaver with or without a heating function. The electric shaver controller may have a default setting, i.e., the lighting module is triggered by activating the hair cutting unit, but wherein the user may deactivate the lighting module using the further input member.

[0152] With respect to the aforementioned predetermined temperature target, a temperature sensor 350 may be used to provide temperature feedback to the controller during one or both of the initial heating phase and the operating phase. The temperature sensor may be carried on the same PCB 38 that carries the lighting elements 20. For example, the temperature sensor 350 may be mounted to the previously discussed first major surface 42 of the PCB in close proximity to one of the lighting elements (e.g., one of the IR or NIR lighting elements). For example, Figure 5 The temperature sensor 350 can be seen in the cross-sectional view of FIG. Providing the temperature sensor directly adjacent to the lighting element provides optimal thermal coupling between the two.

[0153] A thermally conductive path between the first major surface 42 of the PCB facing the light output surface 36 and the light output surface 36 may optionally be provided by the previously described optional light-transmissive potting material 40, which is provided to cover the first major surface 42 of the PCB 38, thereby encapsulating the lighting element 20 and the temperature sensor 350. The potting material also provides thermal coupling between the temperature sensor 350 and the light output surface 34 described above, thereby increasing the accuracy of the temperature sensor in measuring the surface temperature.

[0154] Fig.10 Schematically shown in FIG. 1 is a portion of an example control circuit. The circuit includes circuit components in the lighting module 14 (in the shaving unit 10) and in the body 110 of the shaver. In this example, the lighting module includes the lighting element 20 and also includes a temperature sensor 350 (e.g., a thermistor). The body 110 includes a controller 86. The controller 86 is configured to control the duration of the initial heating phase. The controller is also adapted to control the power level of the lighting element 20 according to the sensed output from the temperature sensor 350 during the operation phase. For example, the controller is configured in this way to adjust the temperature of the light output surface 36 by controlling the lighting element 20 according to the output from the temperature sensor.

[0155] The main circuit in the illustrated example also includes a battery (“BAT”) for powering the lighting module 14 , an electrical connection to the lighting module for powering the lighting module, and a signal connection to the lighting module for receiving a sensing signal from the temperature sensor 350 .

[0156] Controlling the power level of the lighting element may include varying the duty cycle frequency of a pulse wave modulation (PWM) drive scheme.

[0157] In order to control the lighting module to maintain a desired set point temperature, the lighting module includes a temperature sensor 350, such as a thermistor, such as a negative temperature coefficient (NTC) thermistor.

[0158] The controller 86 is capable of sampling the temperature sensor 350 signal and this can be processed by the controller 86 to convert the sensor signal into a temperature. Since temperature changes tend to be slow, the sampling frequency of the temperature sensor is not critical.

[0159] The temperature value obtained can be used in a closed loop system to adjust the desired set point temperature.

[0160] Safeguards may be incorporated to avoid overheating. For example, if the measured signal is outside a certain operating bandwidth (indicating overheating), the lighting module may be automatically disabled.

[0161] Various temperature control module selections are possible. According to one specific example, the controller 86 may include a feedback control loop including the temperature sensor 350 and a proportional-integral (PI) control component.

[0162] Temperature regulation of the shaving unit may be implemented directly based on the temperature reading of the temperature sensor 350. Alternatively, the controller may be adapted to determine a corrected temperature of the light output surface using the output from the temperature sensor and a temperature correction function applied to the output from the temperature sensor, and to control the power level of the lighting element according to the corrected temperature of the light output surface. Here, the corrected temperature may be, for example, an estimated temperature at the skin contact surface, which may be different from the direct temperature measured by the temperature sensor. For example, the corrected temperature may be calculated using a temperature calculation function applied to the temperature output from the temperature sensor.

[0163] According to a further set of embodiments, novel optical means may be provided in the shaving unit 10 for modulating the visible light profile provided at the light output surface 36 by means of one or more visible light illumination elements 64. The shaving unit 10 in this example may be the same or similar to the shaving unit described above with respect to the earlier embodiments. In particular, all features of any of the above-described electric shavers 100 and shaving units 10 are compatible with this further set of embodiments of the present invention, but some features may be omitted. For example, the potting material described above is not necessary.

[0164] By way of introduction to this group of further embodiments, it is noted that it is advantageous to include a visible light lighting element 64 in the plurality of lighting elements 20, the primary function of which is to provide a visible light source for providing a visible light indicator to the user of the activation of the heating function of the lighting module 14. The lighting element for heating produces a light output in a non-visible spectrum, meaning that no visual feedback is provided to the user. By integrating optical feedback in the visible domain at the location of the light output surface 36, the user is able to recognize the operating state.

[0165] It is an object of at least one set of embodiments of the present invention to integrate light processing elements into the shaving unit 10 to modify the content of what would otherwise appear as discrete point source light spots at the light output surface 36. Fig.11 Schematically shown, Fig.11 An example visible light profile 65 produced by a visible light lighting element at light output surface 36 is shown without optics provided in the lighting module. Fig.12 A cross section through such a lighting module 14 is shown without optical means for directing visible light. The forward-pointing visible light illumination element 64 is shown mounted on the first (upper) major surface 42 of the PCB 38. The light output surface 36 can be understood to include a proximate area 420 corresponding to the area of ​​an imaginary projection 422 of the visible light illumination element 64 onto the light output surface, as shown in FIG. Fig.12 For each individual lighting element, this adjacent area 420 is relatively small, which means that the visible light generated by each visible light lighting element 64 appears to the observer 419 as a point source of light on the light output surface 36. However, this does not represent the fact that the actual heat treatment is spread over a wider surface area of ​​the light output surface 36.

[0166] Therefore, according to one or more embodiments, the lighting module 14 is also provided with optics for generating a visible light output at the light output surface 36 provided by the visible light lighting element 64 .

[0167] exist Figures 13 to 15 An example is schematically shown in FIG. 1 and will now be described.

[0168] A shaving unit 10 is provided which comprises an illumination module 14 having one or more infrared (IR) or near infrared (NIR) illumination elements 62 and one or more visible light illumination elements 64 for generating visible light. Figure 13-Figure 15Only one visible light lighting element 64 is shown in the figure, but in other examples, multiple such elements may be provided. Both the IR or NIR lighting element 62 and the visible light lighting element 64 are arranged in optical communication with the light output surface 36. The visible light lighting element 64 is configured and arranged to be activated together with the activation of the IR or NIR lighting element 62 to provide a visible indication of the activation of the IR or NIR lighting element 62. The activation of the IR or NIR lighting element 62 and the visible light lighting element 64 may be controlled, for example, by a controller.

[0169] As previously described, the light output surface 36 can be understood to include one or more adjacent regions 420, each adjacent region 420 including the area of ​​an imaginary projection 422 of a corresponding one of the visible light lighting elements 64 on the light output surface 36. The optical device includes a light guide 412, which is configured to guide the visible light generated by the visible light lighting element 64 to at least a main region 424 of the light output surface, wherein the main region does not include the one or more adjacent regions 420 of the light output surface 36.

[0170] The optical device also includes one or more light attenuating elements 416, each light attenuating element being arranged between a corresponding one of the visible light illumination elements 64 and a neighboring region 420 of the light output surface 36 associated with the corresponding one of the visible light illumination elements 64, and each light attenuating element having a transmittance for visible light that is less than a transmittance of the light guide 412 for visible light. Figures 13 to 15 In the example shown, one or more light attenuating elements 416 each include a layer of light attenuating material 450, which may be partially light attenuating (i.e., translucent) or fully light attenuating, i.e., opaque. In the example shown, the layer of light attenuating material 450 is deposited on a portion of an otherwise light transmissive (e.g., optically transparent) carrier sheet 472 that extends atop light guide member 440 and visible light illumination element 64. In other examples, each light attenuating element 416 may be formed from an integral portion of carrier sheet 472, such as as a light attenuating (e.g., tinted) portion of an otherwise optically transparent sheet.

[0171] The carrier sheet 472 may be optically transparent. However, in other examples, the carrier sheet may be optically transmissive and at the same time optically diffuse or scattering to promote a more uniform distribution of light over the main area 424 of the light output surface.

[0172] Fig.14The modified visible light profile provided to the light output surface due to light guide 412 is schematically shown. Light attenuating element 416 inhibits the direct light path from each visible light illumination element 64 to light output surface 36 , ie to a proximal region 420 of light output surface 36 associated with visible light illumination element 64 .

[0173] exist Figures 13 to 15 In the example of , the light guide arrangement 412 comprises a light guide member 440 arranged to guide the visible light generated by the visible light illumination element 64 in a guiding direction having a main direction component parallel to the light output surface 36. The one or more visible light illumination elements 64 may each comprise, for example, a side-view LED arranged to introduce visible light into the light guide member 440 via an edge surface 442 of the light guide member 440.

[0174] The light guide member 440 may include a light outcoupling element configured to couple visible light out of the light guide member 440 in a direction toward the light output surface 36. For example, the light guide member may include an array of angled light guide facets for reflecting or scattering light outwardly from the light guide member ( Figure 13-Figure 16 Not shown, but for example in Fig.17 (see ).

[0175] Fig.15 Shows Fig.14 0 is a closer cross-sectional view of the PCB 38 arrangement of an embodiment of FIG.

[0176] Fig.16 A view of a skin contact surface 54 of the shaving unit 10 is shown, which in this case is formed by the upper wall 34 of the housing 18 of the lighting module 14 . Fig.16 A light output surface 36 is shown which may form at least a portion of the skin contacting surface 54 . Fig.16 As shown in the above discussion and Figure 13-Figure 15 The optical device shown in FIG. 1 achieves a spatially extended visible light output. As shown in the figure, this corresponds to Fig.14 A main area 424 of the light output surface is shown, to which the visible light of the visible light lighting element 64 is guided by the light guide 412 of the lighting module 14 .

[0177] Figures 13 to 15 The spatial location of the specific visible light illumination element 64 is shown at Fig.16 Shown in.

[0178] Fig.17 Shows Figure 13-Figure 1538, lighting elements and optical arrangement of a lighting module. Visible light lighting element 64 is mounted on first major surface 42 of the PCB, which faces light output surface 36 ( Fig.17 The visible light illumination element 64 is Fig.17 are not directly visible in the image because they are mounted beneath corresponding layers of opaque material 450, thereby hiding them from view.

[0179] In the example shown, each visible light illumination element 64 is a side-emitting visible light illumination element. Fig.17 As shown. The light guide device includes a light guide member in the form of a light guide sheet 460, which is arranged on the first main surface 42 of the PCB. Each light attenuating material layer 450 forms a light attenuating element. The light attenuating element is provided by arranging an optically transparent carrier sheet 472 on the light guide sheet 460, wherein each light attenuating element is provided as an opaque ink layer on a corresponding area of ​​the optically transparent carrier sheet 472, which is located in a direct light path between a corresponding one of the visible light illumination elements 64 and the light output surface, for example, on an area directly above each corresponding visible light illumination element 64.

[0180] Although in this example the light attenuating material layer 450 is provided in the form of an opaque ink layer, other options are possible. Instead of an opaque ink layer, a masking layer that partially attenuates the light may be provided. These may be facilitated by partially light attenuating ink or by a different material. They may be facilitated by an adhesive layer (e.g., a sticker) adhered to the relevant portion of the carrier sheet 472, which in some examples may have a color such as red.

[0181] Furthermore, as described above, although in the example described, the carrier sheet 472 is optically transparent, in other examples the carrier sheet may be an optically transmissive light diffuser to improve the uniformity of the visible light profile provided at the light output surface.

[0182] exist Figure 13-Figure 17In the example of , the light guide member is a light guide sheet 460 that is optically configured to provide a light scattering or diffusing effect so as to spread the visible light output from the visible light lighting element(s) 64 over a wider visible area of ​​the light output surface 36 of the lighting module 14. The visible light lighting element 64 may be a side-directing visible light lighting element, wherein the light guide sheet 460 receives and guides the visible light generated by the visible light lighting element 64 in a guiding direction having a main direction component parallel to the light output surface 36 of the lighting module 14. The visible light lighting element 64 may, for example, be received within a cavity or an opening or a recess formed in a side wall 444 of the light guide member, and wherein light from the visible light lighting element 64 is introduced into the light guide member 440 via an edge surface 442 within the cavity within the light guide member 440.

[0183] The light guide sheet 460 includes a light out-coupling element 462 configured to couple visible light out of the light guide member in a direction toward the light output surface. Fig.17 In the example of , the light guide sheet 460 is constructed to specifically include a linear array of inclined planar facets 462 that are used to scatter light and couple light outwardly from the light guide sheet 460 in the direction of the light output surface 36 above the PCB 38.

[0184] The visible light lighting element 64 is disposed on the same PCB 38 as the IR or NIR lighting element 62 .

[0185] Fig.18 Shows Figure 13-Figure 17 1 is an exploded view of an example lighting module 14. The light output surface 36 of the lighting module housing 18 forms the skin contact surface of the shaving unit. A layered stack is received within the lighting module housing 18, the layered stack comprising: a PCB 38 carrying an IR / NIR lighting element 62 and a visible light lighting element 64 mounted to its first major surface 42, a light guide sheet 460 mounted on the first major surface 42 of the PCB 38 (e.g., by an adhesive), and an optically transparent carrier sheet 472 having opaque ink layers 470 deposited thereon, each ink layer forming a light attenuating element 416. As previously described, the layered stack is encapsulated within the lighting module housing 18 by a potting material 40. Fig.18 Also shown are electrical connection pins 23 provided on the second major surface 44 of the PCB 38 for connecting the lighting elements 62, 64 to a power source in the shaver body. Fig.18 The layer of potting material disposed at the second major surface 44 of the PCB 38 is not shown.

[0186] exist Fig.17In the example of PCB 38, both visible light lighting element 64 and IR or NIR lighting element 62 are mounted on first major surface 42 of PCB 38 facing light output surface 36. However, in an alternative set of embodiments, IR or NIR lighting element 62 may be mounted on first major surface 42, and visible light lighting element 64 may be mounted on second major surface 44 of the PCB opposite first major surface 42, or on first and second major surfaces 42, 44 of PCB 38. In this example, a portion of PCB 38 itself serves as a light attenuating element 416 for visible light lighting element 64 mounted on second major surface 44 of PCB 38, thereby suppressing a direct light path between visible light lighting element 64 on second major surface 44 and light output surface 36.

[0187] Fig.19 An example is schematically shown in FIG. 4. Visible light illumination element 64 is mounted on second major surface 44 of PCB 38. The one or more light attenuation elements mentioned above may be understood to be each formed by a corresponding portion of PCB 38 on which a corresponding one of visible light illumination elements 64 is arranged.

[0188] In this case, the light guide 412 comprises a light guiding and / or light reflecting portion 480 of the housing 18 of the lighting module 14. Thus, in this case, the lighting module housing 18 itself forms at least a part of the light guide. Fig.19 As shown, the inner surface 480 of the lighting module housing 18 can be arranged to direct and / or reflect visible light generated by the visible light lighting element 64 on the second major surface 44 of the PCB 38 toward the light output surface 36. In addition, the housing 18 of the lighting module 14 can be integrally made of the same light-transmissive material that forms the light output surface 36, and the upper wall 34 of the housing 18 and the side walls 50 of the housing 18 can include light directing and / or reflecting portions of the housing 18 of the lighting module 14. In other words, the body of the lighting module housing 18 can be adapted to receive visible light emitted by the visible light lighting element 64 on the second major surface 44 of the PCB 38, and to couple the visible light to the light output surface 36. In some examples, the body of the lighting module housing 18 is adapted to apply a scattering effect to the visible light, thereby causing the visible light to diffuse through the body of the lighting module housing 18. This is referred to as volumetric scattering, and has the effect of providing diffuse visible light illumination of the entire upper wall 34 of the lighting module housing 18, such as Fig. 20 shown.

[0189] In some examples, the light directing and / or light reflecting portion 480 of the housing 18 of the lighting module 14 is arranged to be aligned with the hair cutting unit 12 and / or the support member 22 (see Figure 1- Additional light guiding and / or light reflecting portions of - FIG. 3 ) cooperate to guide and / or reflect visible light generated by visible light illumination element 64 on second major surface 44 of PCB 38 toward light output surface 36 .

[0190] For example, visible light reflecting elements or reflecting surfaces / interfaces can be formed in the body of the lighting module housing 18 and / or the body of the support member 22. The reflecting surface can be configured to provide a total internal reflection (TIR) ​​effect. Reflective and / or scattering elements can be disposed in or around one or more hair cutting units 12, which are arranged to receive at least a portion of the visible light output of the visible light lighting element 64.

[0191] Despite Fig.19 In the example shown, visible light lighting elements 64 are mounted on second major surface 44 of PCB 38, but the use of lighting module housing 18 formed of a light transmissive material for volume scattering of visible light is also compatible with visible light lighting elements mounted on first major surface 42 of the PCB.

[0192] Fig.21 Shows Figure 13-Figure 18 Another perspective view of the first major surface 42 (upper side) and the second major surface 44 (lower side) of the PCB 38 of the illustrated example.

[0193] PCB 38 comprises a central region 502, from which a plurality of (in this case three) elongated arms 504a, 504b, 504c extend outwardly, each arm of PCB 38 having a rod section of smaller width connected to the central region and an end section of wider width. Each end section of wider width carries one or more IR or NIR lighting elements and at least one visible light lighting element. These may be referred to as a first peripheral group 520a, a second peripheral group 520b, and a third peripheral group 520c of lighting elements. The central region also carries one or more IR or NIR lighting elements and at least one visible light lighting element, and these lighting elements may be collectively referred to as a central group 510 of lighting elements. At least one temperature sensor may be disposed on the PCB. The rod sections of the arms of the PCB may be free of electrical components. When assembled, they may carry a light guide member 440, such as a light guide sheet 460.

[0194] When assembled, and as Fig. 22 As schematically shown, the central group 510 of lighting elements can be arranged in a central area 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 can include a central IR or NIR lighting element 512 and at least three central visible light lighting elements 516.

[0195] The lighting module also includes a first peripheral group 520a, a second peripheral group 520b and a third peripheral group 520c of lighting elements, which are arranged respectively between the first hair cutting unit 12a and the second hair cutting unit 12b, the first hair cutting unit 12a and the third hair cutting unit 12c, and the second hair cutting unit 12b and the third hair cutting unit 12c, and each peripheral group includes a peripheral IR or NIR lighting element 522 and at least one peripheral visible light lighting element 524.

[0196] Fig.23 It shows that previously Figure 13-Figure 18 A view of a light guide member 440 in the form of a light guide sheet 460 is shown for installation in Fig.21 PCB 38 of the embodiment of the present invention. Light guide member 440 has a multi-arm geometry corresponding to the geometry of PCB 38. It particularly includes a first portion 530, a second portion 532 and a third portion 534. When assembled, the first portion extends between a first central visible light lighting element in the central visible light lighting element 516 and at least one peripheral visible light lighting element 524 of the first peripheral group 520a of lighting elements. The second portion 532 extends between a second central visible light lighting element in the central visible light lighting element 516 and at least one peripheral visible light lighting element 524 of the second peripheral group 520b of lighting elements. The third portion 534 extends between a third central visible light lighting element in the central visible light lighting element 516 and at least one peripheral visible light lighting element 524 of the third peripheral group 520c of lighting elements. The lighting module also includes a central visible light lighting element 516 and a peripheral visible light lighting element 524 ( Figure 21-23 The optical attenuation element is not shown in the figure, and the optical attenuation element is combined with the previous Figure 12-Figure 18 The embodiments are provided in a similar manner as explained in the examples.

[0197] As described above, the present invention utilizes a controller. The controller can be implemented in a variety of ways using software and / or hardware to perform the various functions required. A processor is an example of a controller that employs one or more microprocessors that can be programmed using software (e.g., microcode) to perform the required functions. However, a controller can be implemented with or without a processor, and can also be implemented as a combination of dedicated hardware that performs certain functions and a processor (e.g., one or more programmed microprocessors and associated circuits) that performs other functions.

[0198] Examples of controller components that may be employed in various embodiments of the present disclosure include, but are not limited to, conventional microprocessors, application specific integrated circuits (ASICs), and field programmable gate arrays (FPGAs).

[0199] In various implementations, a processor or controller may be associated with one or more storage media such as volatile and non-volatile computer memory (such as RAM, PROM, EPROM, and EEPROM). The storage media may be encoded with one or more programs that, when executed on one or more processors and / or controllers, perform the desired functions. The various storage media may be fixed within the processor or controller, or may be transportable so that one or more programs stored thereon may be loaded into the processor or controller.

[0200] By studying the drawings, the disclosure and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments when practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0201] A single processor or other unit may fulfill the functions of several items recited in the claims.

[0202] The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0203] The computer program may be stored / distributed on appropriate media, such as optical storage media or solid-state media provided together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

[0204] If the term "suitable for" is used in the claims or the specification, it should be noted that the term "suitable for" is intended to be equivalent to the term "configured to".

[0205] Any reference signs in the claims should not be construed as limiting the scope.

[0206] Reference numerals

[0207] Shaving unit (10)

[0208] Electric Shavers(100)

[0209] Hair cutting unit(12)

[0210] Lighting Modules(14)

[0211] Lighting Module Housing(18)

[0212] Lighting components(20)

[0213] Supporting member (22)

[0214] Contact pins(23)

[0215] Cavity(32)

[0216] Lighting module upper wall (34)

[0217] Light output surface (36)

[0218] PCB(38)

[0219] Potting Materials(40)

[0220] Potting material layer (41a)

[0221] Additional layer of potting material (41b)

[0222] PCB first main surface (42)

[0223] PCB second main surface (44)

[0224] PCB edge surface(46)

[0225] Housing side wall (50)

[0226] Skin contact surfaces(54)

[0227] Opening(56)

[0228] IR or NIR lighting elements(62)

[0229] Visible light lighting components(64)

[0230] Inner surface of upper wall (72)

[0231] Shaver body (110)

[0232] External cutting member (120)

[0233] Hair entry opening (122)

[0234] Controllers(86)

[0235] Initial heating phase (310)

[0236] Operation phase (320)

[0237] PI control component (334).

[0238] Temperature Sensors(350)

[0239] Light guide device(412)

[0240] Optical Attenuation Components(416)

[0241] The near side area (420) of the output surface Virtual projection(422)

[0242] Output Surface Main Area(424)

[0243] Light guide member (440)

[0244] Light attenuation material layer (450)

[0245] Light guide sheet(460)

[0246] Opaque ink layer (470)

[0247] Optically Clear Carrier Sheet(472)

[0248] Light guiding / reflecting parts(480)

[0249] Lighting Components Central Group (510)

[0250] Central IR or NIR lighting element(512) Central visible light illumination element(516)

[0251] First peripheral group (520a)

[0252] Second peripheral group (520b)

[0253] The third peripheral group (520c)

[0254] Peripheral IR / NIR Lighting Components(522) Peripheral visible light lighting elements(524) Light guide member first portion (530) Light guide member second portion (532) Light guide member third part (534)

Claims

1. An electric shaver (100), comprising a shaving unit (10) and a controller (86), wherein the shaving unit comprises: an upper surface, the upper surface comprising a skin contact surface (54) arranged to contact the skin during operation of the shaving unit; one or more hair cutting units (12); a lighting module (14), the lighting module comprising one or more lighting elements (20) and a light output surface (36) facing the skin, during the operation of the shaving unit, light generated by the lighting elements is exposed to the skin via the light output surface facing the skin, the light output surface is made of a light-transmissive material and forms at least a part of the skin contact surface (54), and the lighting elements are arranged in thermal contact with the light output surface via a thermally conductive path in the lighting module; as well as a support member (22) supporting the one or more hair cutting units (12) and the lighting module (14); and wherein the controller (86) is operably coupled to the lighting module (14) and the controller is adapted to control the lighting element (20) with a driving scheme, the driving scheme comprising: an initial heating phase (310) triggered upon activation of the lighting module, in which the lighting element is driven at an initial power setting until a predetermined temperature of the light output surface (36) is reached; and an operating phase (320) following the initial heating phase, in which the lighting element is driven at an operating power setting such that the temperature of the light output surface is controlled to remain at the predetermined temperature; The maximum power value of the operating power setting is lower than the power value of the initial power setting.

2. The electric shaver (100) according to claim 1, wherein the predetermined temperature is in the range from 40°C to 50°C.

3. The electric shaver (100) according to claim 2, wherein the predetermined temperature is in the range from 41.8°C to 42.2°C, in the range from 44.8°C to 45.2°C, or in the range from 47.8°C to 48.2°C.

4. The electric shaver (100) according to any one of claims 1-3, wherein the electric shaver comprises an input member configured to enable a user of the electric shaver to select the predetermined temperature.

5. The electric shaver (100) according to any one of claims 1 to 3, wherein the one or more lighting elements (20) comprise one or more LEDs.

6. The electric shaver (100) according to any one of claims 1-3, wherein the one or more lighting elements (20) comprise infrared (IR) or near infrared (NIR) lighting elements.

7. The electric shaver (100) according to any one of claims 1 to 3, wherein during the initial heating phase (310), the light beam of at least one of the lighting elements has a highest average light power density at the light output surface (36) compared with the other lighting elements, and wherein the power value of the initial power setting is such that the highest average light power density is between 325 mW / cm 2 and 360mW / cm 2 between.

8. The electric shaver (100) according to any one of claims 1 to 3, wherein activation of the lighting module (14) is triggered by activation of the one or more hair cutting units (12).

9. An electric shaver (100) according to any one of claims 1-3, wherein the electric shaver comprises an additional input component, which is configured to enable a user of the electric shaver to activate and / or deactivate the lighting module (14) independently of the activation of the one or more hair cutting units (12).

10. An electric shaver (100) according to any one of claims 1 to 3, wherein the electric shaver further comprises a temperature sensor (350), and wherein the controller (86) is configured to control the duration of the initial heating phase (310) and the temperature of the light output surface (36) in the operating phase (320) based on an output from the temperature sensor.

11. The electric shaver (100) according to claim 10, wherein the controller (86) comprises a feedback control loop including the temperature sensor (350) and a proportional integral (PI) control member (334).

12. An electric shaver (100) according to claim 10, wherein the lighting module (14) includes a PCB (38), wherein the lighting element (20) is mounted to a first major surface (42) of the PCB facing the light output surface (36), so that the lighting element is optically connected to the light output surface during operation of the lighting module, and wherein the temperature sensor (350) is mounted to the first major surface (42) of the PCB at a position adjacent to one of the lighting elements.

13. The electric shaver (100) according to claim 12, wherein the thermally conductive path comprises a light-transmissive potting material (40), the potting material covering the first major surface (42) of the PCB (38) to encapsulate the lighting element (20) and the temperature sensor (350).

14. An electric shaver (100) according to claim 13, wherein the lighting module (14) has a cavity (32), which is covered by a light-transmissive upper wall (34) of the lighting module including the light output surface (36), wherein the PCB is arranged in the cavity, and wherein the potting material (40) extends between the first main surface (42) of the PCB (38) and the upper wall (34) of the lighting module (14).

15. The electric shaver (100) according to any one of claims 1 to 3, wherein the electric shaver comprises a shaver body (110) coupled to the shaving unit and comprising an electric motor for driving the one or more hair cutting units (12) of the shaving unit; wherein the one or more hair cutting units (12) of the shaving unit each comprise an outer cutting member (120) having a plurality of hair entry openings (122) and an inner cutting member having a plurality of cutting elements, the cutting elements being covered by the outer cutting member and being movable relative to the outer cutting member, and The controller (86) is housed in the shaver body (110).

Images