Device for hair removal or skin treatment

Abstract

The utility model relates to hair or skin treatment based on light. A device for hair removal or skin treatment is provided in which treatment light is passed through an output window and at least a portion of the output window has an electrically controllable light transmittance for the treatment light such that the effective size of the treatment head can be adjusted to fit different treatment areas.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a light-based device for hair removal or skin treatment. BACKGROUND

[0002] For hair removal, light-based epilators are well known. People use epilators or epilators to remove unwanted hair. Typical target areas for women are the face, armpits, arms, legs, bikini line and body. Men also use light-based epilators on the chest and back.

[0003] These different target areas have different surface profiles and thus typically require different treatment heads. For example, the Philips Lumeas epilator has four different attachments, called Body, Facial, Armpit and Bikini.

[0004] Managing multiple treatment heads is a burden for the customer. It would be more convenient to have a single configurable treatment head that can be used for all target locations.

[0005] A solution is disclosed in WO2020 / 035405, which discloses an LED-based light epilator with a reconfigurable treatment head. The treatment head has three LED-bearing surfaces. One selected surface of these surfaces is opened to remove hair. This solution is only suitable for LED epilators. However, the mainstream of epilators is still based on filtered output of a flash lamp, also known as Intense Pulsed Light or IPL.

[0006] IPL devices also have the advantage of potentially enabling a skin rejuvenation mode to be combined with a hair removal mode, or as a mode in a standalone device.

[0007] Therefore, there is still no solution for a low-cost and easily reconfigurable epilator, or indeed more generally, a reconfigurable skin treatment device. It is of particular interest to provide a solution that is suitable for implementation in a light-based epilator or skin treatment device. SUMMARY

[0008] According to an example in accordance with an aspect of the present disclosure, there is provided a device for hair removal or skin treatment, comprising:

[0009] a light source for generating treatment light;

[0010] a controller for controlling the light source; and

[0011] an output window through which, in use, the treatment light is delivered to the skin of a user,

[0012] wherein at least a portion of the output window has an electrically controllable optical transmittance for the treatment light between a first state and a second state, wherein the optical transmittance of the portion of the output window is higher in the first state than in the second state.

[0013] The controllable output window enables the device to be configured for different skin areas without the need to change the attachment or to provide mechanically moving internal components. A portion of the output window can be changed from a first state (e.g. transparent) to a second state (e.g. substantially non-transparent (reflective or opaque)). Preferably, the transparent area of the output window can be controlled to multiple sizes.

[0014] The second state (hereinafter also referred to as non-transmissive state) can be a fully non-transmissive state or can only be less transmissive than in the first state (hereinafter also referred to as transmissive state) such that the reduced light output results in a selected portion of the light output window. Preferably, the second state allows for a transmission of at most 10% of the energy density (at the skin surface) compared to the first state.

[0015] In one set of examples, the non-transmissive state is a light blocking state. In this case, the portion of the output window can be implemented as a switchable glass.

[0016] In case of a switchable glass, the front of the treatment head (facing the user's skin) is a switchable glass which can be electrically controlled to make parts of it non-transparent. This way, the effective area of the treatment head can be adjusted under electrical control.

[0017] In another set of examples, the non-transmissive state is a light reflecting state. In this case, the portion of the output window can be implemented as a switchable mirror. In case of a switchable mirror, the front of the treatment head is a switchable mirror which has a mirror surface facing the inside of the device. The switchable mirror can be electrically controlled such that the portion of the window reflects the light back into the device, where it is reflected again by the optical chamber of the light source and exits through the output window. Some controllable mirrors can also tune the spectrum.

[0018] The device for example comprises an optical chamber with a curved back reflector, wherein the switchable mirror is configured to reflect the treatment light to the curved back reflector. The curved back reflector ensures that the reflected light reaches the output window along a path (with one or more reflections first).

[0019] The output window for example comprises an inner transparent support layer and an outer switchable layer with electrically controllable transmittance. This protects the switchable layer from the internally generated heat.

[0020] The output window for example comprises a pixelated device with pixel-wise control of the optical transmittance. This enables a fine control of the shape and size of the output window which is presented as optically transmissive.

[0021] The controller is for example configured to adjust the light source power in dependence of the optically transmissive area of the output window. When the window size is reduced, the power can be proportionally reduced (or compensated with slightly higher power to compensate for reflection losses) to give the same output energy density (J / cm 2 ). The controller is for example configured to maintain a constant output energy density for a given treatment area when adjusting the optical transmissivity.

[0022] The controller is for example configured to adjust the light source power in dependence of the skin area to be treated. Different illumination powers are suitable for different skin areas.

[0023] The device can further comprise a detection system for detecting which skin areas have already been treated, and the controller is configured to control the optical transmissivity in dependence of which skin areas within the current treatment area covered by the device have already been treated.

[0024] When using (known) sensors to detect the device position on the skin and to track the areas that have already been treated, the output window can be reduced when the device is moved to an area that has already been partly treated, to only cover the missed part.

[0025] The device can be used for the purpose of light-based hair removal or skin treatment. Suitable light sources are for example lasers, flashlamps or LED arrays. In case a flashlamp is used, the light has to pass a filter; the filtered output is called IPL or Intense Pulsed Light.

[0026] The disclosure also provides a control method for a device for hair removal or skin treatment, the device comprising a treatment light source for generating treatment light; and an output window, through which, in use, the treatment light is delivered to the skin of a user; the method comprising:

[0027] electrically controlling at least a portion of the output window for an optical transmissivity of the treatment light between a first state and a second state, wherein the optical transmissivity of the portion of the output window in the first state is higher than in the second state.

[0028] These and other aspects of the disclosure will become apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0029] For a better understanding of the present disclosure, and to show how it can be implemented, reference will now be made, purely by way of example, to the accompanying drawings in which:

[0030] Figure 1 a device for hair removal or skin treatment is shown;

[0031] Figure 2 A typical IPL treatment head is shown; and

[0032] Figure 3 shows three possible ways of varying the area of the output window. DETAILED DESCRIPTION

[0033] The present disclosure will be described with reference to the accompanying drawings.

[0034] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of apparatuses, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. These and other features, aspects, and advantages of the apparatuses, systems and methods of the present disclosure can be better understood from the following description, appended claims, and accompanying drawings. It should be understood that the drawings are diagrammatic and schematic only, and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings for like or similar items.

[0035] The present disclosure provides an apparatus for hair removal or skin treatment, wherein treatment light is delivered through an output window, and at least a portion of the output window has an electrically controllable transmissivity for the treatment light, such that the effective size of the treatment head can be adjusted to suit different treatment areas.

[0036] Figure 1 An apparatus 10 for hair removal or skin treatment is shown, in particular an IPL apparatus as an example. The apparatus comprises a housing 12 which houses a flash lamp 14 for generating treatment light in the present example. A controller 16 is provided for controlling the light source. The light source delivers treatment light through an output window 18 to the skin of a user (and in turn to user hair on the skin surface).

[0037] According to the present disclosure, at least a portion of the output window 18 has an electrically controllable optical transmissivity for the treatment light, i.e. for light having a frequency corresponding to the frequency of the treatment light. The optical transmissivity is controllable between a first state and a second state. The first state has a higher optical transmissivity, e.g. is transparent, compared to the second state, e.g. light blocking. The output window has a controllable area in the first state (i.e. optically transmissive), and this enables the apparatus to be configured for different skin areas without the need to change the attachment or provide internal components for mechanical movement. The second state, compared to the first state, for example allows a transmission of at most 10% of the energy density (at the skin surface).

[0038] In Figure 2A typical IPL treatment head is shown in Figure 1. The light source 14 comprises for example a xenon flash lamp. The flash lamp is surrounded by reflective surfaces, including a curved back reflector surface 20 which reflects light to an output window 18. The curved reflector shapes the light from the flash lamp into a more or less parallel beam. All light from the xenon flash lamp reaches a front plate 22 including the output window 18 either directly or after one or more reflections.

[0039] The present disclosure provides for a variable area of the optically transmissive part of the output window 18. In the case that the output window is fully open (i.e. fully optically transmissive), the device is for example in a mode of applying treatment to a maximum target area (e.g. on an arm).

[0040] For treating smaller areas, for example in a mode of applying treatment to a face, a smaller optically transmissive output window is required. This is achieved by electrically controlling the output window 18 to allow light to exit the device only from a part of the total window area.

[0041] A first option is to make a part of the window non-transparent to block light. In this case the blocked part will absorb light and heat up, so the design needs to take this heating into account.

[0042] An alternative method is to electrically switch a part of the output window into a mirror which reflects light back into the device, where it is reflected again (from the back of the flash lamp, from the reflective surface 20) back to the output window.

[0043] Figure 3 shows three possible ways of varying the area of the optically transmissive part of the output window. In a first example of Figure 3a, there is a central window area 30 which is always optically transmissive, and a peripheral area 32 which can be controlled between a transmissive and a reflective or blocking state. Figure 3A In a second example of Figure 3b, there is a lower window area 34 which is always optically transmissive, and an upper area 36 which can be controlled between a transmissive and a reflective or blocking state.

[0044] Figure 3B In a third example of Figure 3c, there is a central band area 38 which is always optically transmissive, and upper and lower bands 40 which can be controlled between a transmissive and a reflective or blocking state.

[0045] In a fourth example of Figure 3d, there is a central band area 38 which is always optically transmissive, and a central band 42 which can be controlled between a transmissive and a reflective or blocking state. Figure 3C

[0046] ​​There can be only two states, such as a fully transmissive window and a window configured as shown in the three examples of Figure 3. However, instead, the output window can be pixelated, so that it can be driven into any desired pattern of transmissive and non-transmissive states. Thus, instead of having only two different states, there can be any number of states, such as four states corresponding to the four known sizes of individual treatment heads known in the prior art as described above (i.e. different sizes of transmissive areas). Even full flexible control of the pixelated output window can be provided to enable additional functionality as described below.

[0047] In one preferred example, there is a rectangular optical transmission opening as shown in Figure 3A and the size of the rectangular opening of the output window is controllable.

[0048] When the optical properties can be controlled at the pixel level, it is also possible to control the light treatment to provide light blocking for local spots, such as moles, freckles and pigmented spots. In addition, adaptive treatment can also be implemented, where the treatment light intensity can be adjusted based on the controllable window transparency or opacity.

[0049] For each configuration of reduced area of transmissive portion of the output window, the system can control the light source power, such as to deliver the desired energy density (in J / cm 2 as a part of a calibration process during device development.

[0050] Sensors are known to be incorporated to track movement of light-based devices for hair removal or skin treatment. For example, the device can have a mode where the user moves the device over the skin while the sensor tracks the position and displacement.

[0051] The sensor is for example an optical sensor to track movement based on observed changes in captured images. The working mechanism of such optical sensors is similar to the optical mouse of a computer (a mouse embedded with an optical sensor) used to track mouse movement. Position tracking can also be implemented using a camera embedded in the device.

[0052] Typically, the user will move the device over the treatment area several times to ensure full coverage. When the user moves the device over an area that includes previously treated portions and previously untreated portions, the system can adjust the size and shape of the optically transmissive portion of the output window to avoid re-treating already treated portions. The light source power can be adjusted again to ensure that the required energy density is delivered through the area-reduced output window. This way, over-treatment or under-treatment of different skin areas can be prevented.

[0053] Figure 2The curved reflector shown avoids the possibility of light being trapped between the two parallel mirrors and reflected multiple times when a reflective output window is used. Instead, after one or several reflections, the light will escape towards the transmissive portion of the output window.

[0054] Electrochromic glass or mirror components typically have an operating temperature range; for example, Kent Optronics' "e-Transflector" electrically switchable semi-transparent mirror operates from -10°C to 60°C. Therefore, the electrochromic layer is preferably applied to the outside of the output window and has an additional transparent material (such as a glass substrate) to insulate it from the heat of the light source.

[0055] In current IPL devices, the outer side of the output window will never reach 60°C, as this is above the maximum external skin contact operating temperature to avoid causing pain to the user. If no additional substrate is required, the temperature inside the cavity can alternatively be designed to be kept below the operating temperature of the electrochromic material.

[0056] Different power levels and different output window areas can be adapted to different skin regions.

[0057] As an example:

[0058] 4cm can be provided 2 5.5 J / cm 2 The output is used for body processing;

[0059] 3cm can be provided 2 6.5 J / cm 2 The output is used for armpit or bikini treatment;

[0060] 2cm can be provided 2 Up to 6J / cm 2 The output is used for the face. The cutoff wavelength can also be different.

[0061] Electro-optical efficiency is crucial because heat generation is a primary cause of low flash rate. However, with a reduced transmission area of ​​the output window and consequently lower power, the total heat generated per flash will be lower than with a full output window. For example, based on a 2cm... 2 Up to 6J / cm 2 The above numbers are equivalent to 12J, and 4cm 2 5.5 J / cm 2 This is equivalent to 22J. Therefore, the smaller the output window, the lower the total power used, and consequently, the less heat is generated.

[0062] The present disclosure can be applied to IPL epilators and skin treatment devices. However, it can also be applied to other (optical) epilator designs, for example designs using LEDs or lasers. It can also be applied to other skin treatment devices using light.

[0063] In the implementation of the claimed disclosure, variations of the disclosed embodiments will occur to those skilled in the art in light of the disclosure and the accompanying drawings. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality.

[0064] The functions implemented by the processors can be implemented by a single processor or by a plurality of separate processing units, which can be seen as collectively forming a "processor". In some cases, these processing units can be located far away from each other and communicate with each other in a wired or wireless manner.

[0065] The fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to obtain an advantage.

[0066] If the term "adapted" is used in a claim or the specification it should be noted that the term "adapted" is intended to be equivalent to the term "configured to". If the term "means" is used in a claim or the specification it should be noted that the term "means" is intended to be equivalent to the term "system", and vice versa.

[0067] Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A device (10) for hair removal or skin treatment, characterized in that, comprising: a light source (14) for generating treatment light; a controller (16) for controlling the light source; and an output window (18) through which, in use, the treatment light is delivered to the user's skin, wherein at least a portion (30, 36, 40) of the output window (18) has an electrically controllable optical transmittance for the treatment light between a first state and a second state, wherein the optical transmittance of the portion of the output window is higher in the first state than in the second state.

2. The apparatus of claim 1, wherein, The second state is a light blocking state.

3. The apparatus of claim 2, wherein, The portion of the output window comprises a switchable glass.

4. The apparatus of claim 1, wherein, The second state is a light reflecting state.

5. The apparatus of claim 4, wherein, The portion of the output window comprises a switchable mirror.

6. The apparatus of claim 5, wherein, comprising an optical chamber with a curved back reflector (20), wherein the switchable mirror is configured to reflect the treatment light to the curved back reflector.

7. The apparatus of any one of claims 1 to 6, wherein, The output window comprises an inner transparent support layer and an outer switchable layer with an electrically controllable transmittance.

8. The apparatus of any one of claims 1 to 6, wherein, The output window comprises a pixelated device with pixel-wise control of the optical transmittance.

9. The apparatus of any one of claims 1 to 6, wherein, The controller (16) is configured to adjust the light source power depending on the area of optical transmittance of the output window.

10. The apparatus of claim 9, wherein, The controller is configured to maintain a constant output energy density for a given treatment area while adjusting the optical transmittance.

11. The apparatus of any one of claims 1 to 6, wherein, The controller is configured to adjust the light source power depending on the skin area to be treated.

12. The apparatus of any one of claims 1 to 6, wherein, Further comprising a detection system for detecting which skin areas have already been treated, wherein the controller is configured to control the optical transmittance depending on which skin areas within the current treatment area covered by the device have already been treated.

13. The apparatus of any one of claims 1 to 6, wherein, The light source comprises a flash lamp.

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