Device for removing hair or treating skin

Abstract

A device for hair removal or skin treatment generates treatment light and skin pigmentation analysis light, both of which are delivered to the skin via a reflective housing. Skin pigmentation analysis light is detected after reflection by the skin, and the detector is located outside the reflective housing. The reflective housing includes a light escape opening or window, wherein a direct path of analysis light not passing through the light escape opening or window is aligned with the detector. This reduces signal offset caused by non-reflected light from the light source that generates the analysis light.

Description

Technical Field

[0001] The present invention relates to a device for hair removal or skin treatment, particularly by applying treatment light to the skin. Background Technology

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

[0003] One common type of phototherapy hair removal device is based on the filtered output of a flash lamp, called Intense Pulsed Light (IPL). A safety feature known for home-use phototherapy hair removal devices is the inclusion of skin pigmentation sensors that measure a particular user's skin tone, or more specifically, their melanin index. Melanin is the substance that causes skin pigmentation. For example, Philips' IPL-based phototherapy hair removal devices have different treatment heads for treating different areas of the body, and each head is equipped with a skin pigmentation sensor.

[0004] These devices can then provide recommendations indicating that it is safe for a particular user to use the IPL device (and block the flash if it is not safe). Recommendations on safe device settings can then be provided, or the device can automatically adjust to ensure safety.

[0005] Typical pigmentation sensors are based on measuring the ratio of light reflected (or backscattered) from the skin at two different wavelengths (e.g., 660 nm and 880 nm). This method takes advantage of the fact that the absorption coefficient of melanin decreases with wavelength.

[0006] Based on data from several IPL studies, it has been found that the melanin index (MI) is related to luminance (L) in the CIELAB color space defined by the International Commission on Illumination (CIE). There is a good correlation between the two. Therefore, another method for measuring the melanin index is based on measuring the brightness of reflected light.

[0007] Current solutions that embed skin pigmentation sensors into processing head attachments are costly and result in a large processing head area, which can limit the user's field of vision for the area to be treated.

[0008] It would be desirable if the phototherapy hair removal device could provide skin pigmentation sensing within the main body of the device, rather than in the treatment head attachment. However, the challenge in implementing a skin pigmentation sensor in a phototherapy hair removal device lies in the positioning of the sensor's detector and the light source.

[0009] The light signal received at the detector has two contributions. Light reflected or backscattered from the skin forms the useful signal. Additionally, there is light propagating directly from the light source to the detector (either along the direct line of sight or via a reflective surface, such as the glass housing of an IPL flash lamp or a light guide around the lamp). This signal can be detected even without skin and can be considered as offset light. Unless the optics of the colorimetric sensor are completely separated from the path of the processed light (which is disadvantageous in terms of cost and size), the offset light tends to be of a similar magnitude to the useful signal. Noise is typically proportional to the combined signal including both contributions. Therefore, the variance of the MI (Minimum Interference Rate) measurement associated with the useful signal-to-noise ratio exceeds acceptable limits.

[0010] Therefore, it is also of interest to provide a phototherapy hair removal device that provides skin pigmentation sensing while effectively and robustly reducing the contribution of offsets to the detection signal, thereby providing accurate MI measurements with minimal noise. Summary of the Invention

[0011] This invention is defined by the claims.

[0012] According to one aspect of the present invention, an apparatus for hair removal or skin treatment is provided, the apparatus comprising:

[0013] A light source system, comprising a processing section for generating processing light and an analysis section for generating skin pigmentation analysis light;

[0014] Reflective housing, for processing light and analyzing skin pigmentation; light is delivered to the skin within this reflective housing.

[0015] A detector for detecting skin pigmentation analysis light reflected from the skin, wherein the detector is located outside the reflective housing; and

[0016] A controller, used to control the light source system, is configured to determine skin pigmentation based on detected skin pigmentation analysis light.

[0017] The reflective housing includes a light escaping opening or window, wherein there is no direct path from the analysis section of the light source system through the light escaping opening or window to align with the detector.

[0018] This device provides processing light and analytical light (for determining skin pigmentation). A detector is used to analyze skin pigmentation. To reduce signal offset that degrades the signal-to-noise ratio, the device prevents the pigmentation analysis light from reaching the detector before being reflected by the skin. This is achieved by having the analytical light pass through an exit opening or window. An exit opening or window creates a direct optical path between the skin and the detector, but in the light source system, particularly the part generating the skin pigmentation analysis light, there is no such direct path between the light source and the detector. It should be noted that the direct path can be a straight path through the opening, but the exit window can deflect or refract the light (received directly from the analytical part of the light source system).

[0019] The direct path from the light source system to the detector is blocked (i.e., the light source system does not overlap with the path between the skin and the detector). This is achieved by selecting the position and size of the light escaping opening and the position and size of the detector such that (i) the angle between the line of sight from the analytical portion of the light source to the escaping opening or window and (ii) the line of sight from the detector to the escaping opening or window is greater than half of the analytical light source receiving angle defined by the escaping opening.

[0020] It should be noted that skin reflection can include specular and diffuse reflection from the air-skin interface, as well as backscattering from deeper layers of the skin.

[0021] The reflective housing includes, for example, a curved rear reflector and a reflective sidewall, the curved rear reflector surrounding the processing portion of the light source system on the side opposite the skin contact area of ​​the device, and the reflective sidewall between the curved rear reflector and the skin contact area.

[0022] This is a known reflector system for IPL devices. The curved reflector is, for example, a parabolic or partially parabolic reflector, and the sidewalls are tubular reflectors. The tubular reflector can have a circular, rectangular, or other cross-sectional shape.

[0023] Light escapes from openings or windows, for example, positioned at:

[0024] At the reflective sidewall; or

[0025] At the edge of the curved rear reflector adjacent to the reflective sidewall.

[0026] The processing and analysis sections of the light source system, for example, share the same light source. In such a device, there is only one light source, and it is controlled in both analysis and processing modes.

[0027] In this configuration, the controller can be configured to control the (shared) light source to provide a pre-flash, which is used as pigmentation analysis light before the processing light is provided.

[0028] The shared light source of the light source system includes, for example, a flash unit, and the device includes a main capacitor unit and a boost capacitor unit for storing charge to deliver energy to the flash unit, wherein a controller is configured to discharge the boost capacitor unit to provide a pre-flash. The capacitor charge provides a current source through the lamp, where electrical energy is converted into light energy. This provides a simple method for implementing a pre-flash function.

[0029] The detector may include a first detector region and a second detector region, each having an associated narrowband filter. This allows a single-wavelength or broadband light source to be used to provide measurements at both wavelengths.

[0030] The processing section of the light source system includes, for example, a first light source, and the analysis section of the light source system includes a second light source, wherein the second light source is positioned outside the reflective housing, and the reflective housing includes a light incident opening for receiving pigmentation analysis light from the second light source.

[0031] In this set of examples, independent light sources are used, allowing them to be optimized for their respective functions. Then, a second light source can be positioned outside the reflective housing, eliminating the need to increase the size of the reflective housing.

[0032] The second light source can include two light source elements with different wavelengths, enabling measurements at different wavelengths again.

[0033] The light escaping opening or window is, for example, sized and positioned such that light reflected from substantially the entire skin area to be processed by the device is projected directly onto the detector through the light escaping opening or window. For example, at least 80% or at least 90% or all of the skin area may have a direct optical path through the light escaping opening to the detector.

[0034] In this way, the light escaping opening or window comprises the envelope shape of a set of optical paths between the skin region to be treated and the detector. In one design, the size and shape of the light escaping opening or window correspond to the shape of the envelope of this set of optical paths. This means that only light from the skin has a direct path to the detector, which provides optimal photon collection efficiency.

[0035] The device may also include a lens at the light escape opening or window. This allows for the use of a smaller opening or window while maintaining photon collection efficiency.

[0036] The light escape opening or window may alternatively include an opening comprising a structured reflector for reflecting light directly received from the analysis section of the light source. In this way, a straight path between the analysis section of the light source system and the detector can be allowed, but the structured opening or window deflects the light to prevent the direct path from reaching the detector.

[0037] In all designs, the positioning angle between (i) the normal to the skin surface and (ii) the path from the center of the skin treatment area to the detector is greater than half the angle subtended by the treatment beam incident on the skin in the same plane as the positioning angle. This minimizes specular reflections from the skin incident on the detector. Specular reflections do not contain information about the level of pigmentation.

[0038] The controller can be configured to determine skin pigmentation based on: analysis of two wavelengths of skin pigmentation analysis light; or analysis of the brightness of skin pigmentation analysis light.

[0039] These and other aspects of the invention will become apparent and be elucidated with reference to one or more embodiments described below. Attached Figure Description

[0040] To better understand the invention and to more clearly illustrate how to practice it, reference will now be made to the accompanying drawings by way of example only, in which:

[0041] Figure 1 An IPL device is shown;

[0042] Figure 2 A first example of a phototherapy hair removal device 50, comprising a light source system and a detector, is shown;

[0043] Figure 3 A partial cross-section of the reflective housing surrounding the flash lamp is shown;

[0044] Figure 4 It shows Figure 2 The first alternative device;

[0045] Figure 5 It shows Figure 2 The second alternative device; and

[0046] Figure 6 It shows Figure 2 The second alternative device; and

[0047] Figure 7 The angular distribution is shown as the processed light leaves the device and enters the skin. Detailed Implementation

[0048] The invention will be described with reference to the accompanying drawings.

[0049] It should be understood that while the detailed description and specific examples indicate exemplary embodiments of the apparatus, system, and method, they are for illustrative purposes only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, system, and method of the present invention will become better understood from the following description, the appended claims, and the accompanying drawings. It should be understood that the drawings are merely schematic and not drawn to scale. It should also be understood that in all the drawings, the same reference numerals are used to indicate the same or similar parts.

[0050] This invention provides an apparatus for hair removal or skin treatment that generates treatment light and skin pigmentation analysis light. The light is delivered to the skin via a reflective housing. The skin pigmentation analysis light is detected after reflection from the skin, and the detector is located outside the reflective housing. The reflective housing includes a light escape opening or window, wherein there is no direct path of the analysis light passing through the light escape opening or window aligned with the detector. This reduces signal offset caused by non-reflected light from the light source generating the analysis light.

[0051] Figure 1 An IPL device 10 is shown, which is in the form of a handheld device having a handle 12 with a trigger 14 and an IPL light source 16 that provides light through a light delivery window 18. A controller 20 controls the light source 16 to deliver light flashes to the light delivery window 18.

[0052] Figure 1 The device also has an output interface 24, such as a screen and / or indicator lights and / or a speaker. The output interface to the user may be provided alternatively or additionally by a remote device with which the handheld device communicates. A skin detection sensor 26 is used to detect skin contact. The skin detection sensor may include a single sensor, or two or more sensors, to detect whether the light output window is flush against the skin.

[0053] When using the device, the user places the light output window onto the skin and presses trigger 14 to deliver a light pulse. The user then slides the device onto the skin to the next processing position (or lifts the device and repositions it) and applies the trigger to deliver the next flash. In some devices, it may also be possible to keep the trigger pressed during line processing. A flash occurs automatically whenever the capacitor in the device is sufficiently charged, typically depending on the setting of 1 to 2 seconds. The user can then move the device to the next point, wait for the next flash, and then move again.

[0054] It is known that a skin pigmentation sensor 30 is provided as part of a processing device to provide personalized recommendations and safety features to individual users.

[0055] This invention relates to an improved integration of skin pigmentation analysis into this type of device.

[0056] The device of the present invention has a photo-hair removal processing unit, such as an intense pulsed light (IPL) light source, and a reflector having a reflective inner surface for providing shielding against leakage of the intense pulsed light during use to avoid eye damage, and for providing effective guidance of the intense pulsed light to direct it onto the target skin area.

[0057] Skin pigmentation sensing utilizes a light source (which can be an IPL light source or a separate light source dedicated to analysis) and a detector. An escape window or opening is arranged in the wall of the reflector to provide an escape path for backscattered light to the detector, thus exposing the detector to backscattered light while minimizing offset.

[0058] Figure 2 A first example of a phototherapy hair removal device 50 is shown, which has a light source system and a detector.

[0059] In this example, the light source systems S and T comprise a single light source that combines a processing section T for generating processing light and an analysis section S for generating skin pigmentation analysis light. Although they can be a single shared light source, they will be referred to below as the processing light source and the analysis light source, respectively.

[0060] The light guiding system includes a reflective housing 60, within which processing light and skin pigmentation analysis light are delivered to the skin. A detector D is used to detect the skin pigmentation analysis light reflected and / or backscattered by the skin. The detector D is located outside the reflective housing.

[0061] A controller 70 is provided for controlling the light source systems S and T and for determining skin pigmentation in a known manner based on the detected skin pigmentation analysis light.

[0062] The reflective housing 60 includes a light escaping opening or window 62 (hereinafter simply referred to as the "window"). There is no direct path from the light source system (more specifically from the analytical light source S) through the window to align with the detector D.

[0063] In this context, a "direct path" refers to the optical path from the analysis light source S to window 62, which then passes through the window. Such a direct optical path therefore does not interact with the skin. Thus, a straight line can exist from the analysis light source S to the detector D through the window, but if the window provides a deflection (refraction or reflection) of the incident light so that it cannot reach the detector, then such a direct path also does not exist.

[0064] The device provides processing light and analysis light (for determining skin pigmentation). By avoiding the direct path described above, signal offset issues are reduced. The pigmentation analysis light is prevented from reaching the detector before being reflected or backscattered by the skin.

[0065] Figure 2 The optical path angles are shown. The optical path from the analysis light source S to window 62 extends along general direction 52, with a (total) angular extension β reaching the boundary of the window. The optical path from the skin to the detector D through window 62 extends around the central path 54 at an angle γ relative to the normal to the skin surface. The angle between the two central paths 52, 54 is α.

[0066] The direct path from the analytical light source S to the detector is blocked.

[0067] exist Figure 2 In the example, the window is open, so it does not deflect or reflect the light path. In this case, obstruction is achieved by selecting the window position and size, as well as the position and size of the detector D, such that the angle α between (i) the line of sight 52 from the analysis light source to the window and (ii) the line of sight 54 from the detector to the window is greater than half of the analysis light source receiving angle β / 2.

[0068] In other examples, the window has light processing capabilities, which means that the direct path does not have to be a straight line, so the above relationship does not apply.

[0069] Therefore, more generally, the position, size, and structure of the window, as well as the position of the detector D, are configured such that light emitted from the analysis light source S onto the window is substantially blocked from reaching the detector D.

[0070] As mentioned above, an IPL flash lamp can be used as an analytical light source for colorimetric analysis. Pigmentation sensing should be able to be performed with the aid of a pre-flash before processing the flash.

[0071] For pre-flash, the lamp can operate at low flash energy (e.g., <5% of the processing flash energy). The pre-pulse must be able to sense pigmentation, while the pulse intensity is insufficient for phototherapy hair removal and potentially causes skin damage if the skin is (too) dark.

[0072] Some known phototherapy hair removal devices (such as the Philips Lumea device) have a so-called boost capacitor in addition to the main capacitor. The boost capacitor supports the ignition of the plasma in the lamp at the start of the flash. A pre-flash can be generated by discharging only the boost capacitor without using the main capacitor. Alternatively, the main capacitor is used, but the discharge is cut off after a portion of the typical pulse length.

[0073] Figure 3A partial cross-section of the reflective housing 60 surrounding the IPL flash lamp, which again serves as both the processing light source T and the analysis light source S, is shown. Behind the lamp, the light guide is closed by a curved (e.g., parabolic or partially parabolic) rear reflector 60a. The reflector reflects rearward-emitted light and creates a degree of collimation in the forward beam. The rear reflector is spaced from the skin by a tubular reflector 60b, which, for example, has a rectangular or circular cross-sectional shape.

[0074] Flash units S and T, for example, have an inner diameter (d_inner) of 2 mm and an outer diameter (d_outer) of 4 mm. They are positioned close to the rear reflector 60a.

[0075] In this example, window 62 is positioned within rear reflector 60a, just before the transition to the straight tubular portion 60b of reflector 60. Light originating from flash lamps S and T and passing through the window will be retained within the tapered section 64 (i.e., a two-dimensional shape in a single plane). Detector D is arranged outside this section.

[0076] The tapered section 64 of the optical path from the flash lamp S and T across the entire outer diameter D_outer is shown. This further reduces the offset than the minimum requirement mentioned above.

[0077] To enable MI measurement based on two wavelengths, detector D can be configured with two sensitive regions, each equipped with a different narrowband filter. Suitable center wavelengths for these filters are 660 nm and 880 nm. For brightness-based detection, no filters are required.

[0078] The standard deviation σ_MI of the melanin index has been simulated by placing the detector directly behind (inward) the opening of the primary reflector as the standard approach, and by the detector positioning according to the invention. In the case of pre-flash from the IPL flash lamp, the source of noise is the spectral variability of the lamp, which has been assumed to be 5% for this modeling.

[0079] The standard solution yielded a σ_MI of 156, while the solution of this invention reduces σ_MI to 56, indicating improved accuracy in MI measurement.

[0080] Figure 4 An alternative solution is shown in which the analysis light source is not an IPL flash lamp, and therefore there are separate analysis light source S and processing light source T.

[0081] exist Figure 4In the example, window 62 is located at the reflective sidewall 60b. Furthermore, the analysis light source S is positioned outside the light-guiding cavity defined by the reflector. Light from the analysis light source S enters the reflector through another window 66. However, the same angular conditions described above also apply.

[0082] For a dual-wavelength method for measuring pigmentation, the analytical light source S can include two LEDs with different peak wavelengths (e.g., 660 nm and 880 nm). The detector D only needs to have a single sensitive region. Alternatively, a broadband (white, blue + phosphor) LED can be used in combination with a detector having two sensitive regions equipped with different narrowband filters.

[0083] A (solid) light guide, such as an optical fiber, can be used between the analytical light source S and the opening 66 in the light guiding system. This allows the analytical light source S to be positioned at a distance with minimal optical loss. A sufficiently large air gap between the analytical light source S and the rear reflector 60a isolates the analytical light source from the high voltage applied to the reflector for igniting the flash.

[0084] Another method of electrical isolation is to set an isolation window (plus a conductive layer to resist capacitive coupling) between the light source S and the opening 66 in the rear reflector.

[0085] The analysis light source S can alternatively be located on the same side of the light guiding system as window 62. In another variation, the analysis light source S and the detector D emit and receive light from the same window 62, respectively. The analysis light source can be positioned to guide light directly to the skin or to the skin via reflection from reflector 60.

[0086] As mentioned above, a high ignition voltage is typically applied to the rear reflector, such as approximately 15 kV. This can also damage detector D, which is connected to PCB components near ground potential, due to electrical breakdown and / or capacitive current induction. Furthermore, the temperature of the air layer surrounding the rear reflector and lamp housing exceeds 200°C.

[0087] In light of the main positioning requirements of the detector as described above, the distance from detector D to the rear reflector 60a can be increased to reduce the risk.

[0088] Optionally, the position and size of window 62 and the position of detector D are configured such that the detection collection angle φ yields the optimal photon collection efficiency.

[0089] exist Figure 5 In the diagram, the receiving angle φ of detector D is illustrated and shown to cover the entire processing area. An added advantage of this full receiving angle is that pigmentation is measured as an average value over the entire processing window, rather than representing the value of just a small spot.

[0090] To ensure that the entire skin area is detected by the detector, the window 62 is sized and positioned such that light reflected from substantially the entire skin area to be processed by the device is projected directly onto the detector through the window. This window can be larger than the envelope formed by the direct optical paths to the detector.

[0091] However, to provide optimal photonic efficiency while minimizing the contribution of stray light to signal offset, the window can have a size and shape that matches the envelope formed by the direct optical path from the entire skin region to the detector. The smaller the window size, the less chance some light (e.g., light reflected by a filter without an anti-reflective coating) has of reaching the detector without being reflected by the skin. The aforementioned envelope is the minimum size that still provides optimal photonic efficiency. This means that only light from the skin has a direct path to the detector.

[0092] In the example above, the window simply includes an opening. However, a lens can be used at window 62 to reduce the size of the window while maintaining surface coverage.

[0093] exist Figure 6 In another example shown, window 62 is a transparent window positioned within the rear reflector, but configured such that the angle of incidence corresponding to the direct light from the analysis light source S is not transmitted. Light scattered from the skin is incident at different angles and transmitted to detector D.

[0094] This angle-dependent transmission through the window can be created by a (triangular) groove or diffraction structure on one surface of the window. Thus, light from the analysis source is reflected by total internal reflection, preventing a direct path to the detector. Alternatively, a grating can be used to prevent direct light from the analysis source from escaping from window 62. The grating can be, for example, based on a triangular groove.

[0095] Photonic hair removal devices typically include a processing spectral filter between the flash and the skin for optimal and safe photonic hair removal. Due to Fresnel reflection, the surface of this filter reflects a small portion of the incident light backwards. These reflections form a virtual light source, which contributes to the offset recorded by the detector.

[0096] Preferably, both sides of the spectral filter are coated with an appropriate anti-reflective coating to minimize this offset contribution. The detector configuration explained above reduces the standard deviation of the melanin index, σ_MI, from 156 to 56. Further modeling shows that using an anti-reflective coating on both sides of the filter can further reduce it to 41.

[0097] The position and size of window 62 and the position of detector D can be configured such that the angle γ between the line of sight 54 from detector D to the center of window 62 and the normal to the skin surface (see [reference]). Figure 2This results in minimal specular reflection incident on detector D.

[0098] Specifically, the position and size of window 62 and the position of detector D are configured such that the angle γ between the line of sight 54 from detector D to the center of window 62 and the normal to the skin surface is greater than half of the angle τ of the central collimated portion of the beam incident on the skin.

[0099] Figure 7 This shows the angular distribution (θ) as the processed light leaves the device and enters the skin. x and θ y It is the angle in the zx and zy planes, where the z-axis is perpendicular to the x-axis. Figure 1 (The optical axis of the device is aligned as shown in the image).

[0100] In this example, the axis of the rear reflector extends in a direction perpendicular to the zy plane. As a result, the beam is collimated in this plane until the beam angle τ (e.g., defined as half-width at half-maximum).

[0101] A portion of the light incident on the skin undergoes specular reflection, where the angle of departure equals the angle of incidence. Specular reflection does not contain information about pigmentation levels. In particular, specular reflection at the air-skin interface is the same for both light and dark skin. Differences in skin pigmentation levels are only reflected in light that has penetrated the skin, reached the location of melanin, and is then backscattered.

[0102] A detector positioned at an angle γ > τ (an angle taken within the zy plane) will not see specular reflection. In this way, specular reflection from the skin into detector D is avoided.

[0103] It should be noted that the detector's receiving angle is determined by reflection from the reflector's sidewalls rather than direct observation of the skin. Only light scattered by the skin and thus containing relevant skin information reaches detector D. This improves the accuracy of pigmentation measurements, especially for dark skin.

[0104] Alternative sites, for Figure 4 In this configuration, light can be cross-polarized to avoid specular reflection. This is achieved by using a polarized light source and detector, or by placing a polarizer in front of the light source and detector.

[0105] Based on a study of the accompanying 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 articles "a" or "an" do not exclude a plurality.

[0106] The fact that certain measures are stated in mutually different dependent claims does not indicate that a combination of these measures cannot be used advantageously.

[0107] If the term "suitable" is used in the claims or description, it should be noted that the term "suitable" is intended to be equivalent to the term "configured as". If the term "apparatus" is used in the claims or description, it should be noted that the term "apparatus" is intended to be equivalent to the term "system", and vice versa.

[0108] No reference numerals in the claims should be construed as limiting the scope.

Claims

1. An apparatus for hair removal or skin treatment, comprising: A light source system (S, T) includes a processing section (T) for generating processing light and an analysis section (S) for generating skin pigmentation analysis light. A reflective housing (60) is provided within which the processing light and the skin pigmentation analysis light are delivered to the skin; A detector (D) for detecting skin pigmentation analysis light reflected by the skin (56), wherein the detector (D) is located outside the reflective housing (60); as well as Controller (70), the controller being configured to control the light source system, wherein the controller is configured to determine skin pigmentation based on the detected skin pigmentation analysis light, The reflective housing (60) includes a light escaping opening or window (62) in which there is no direct path from the analysis section (S) of the light source system (S, T) through the light escaping opening or window (62) to align with the detector (D).

2. The device of claim 1, wherein the reflective housing comprises a curved rear reflector (60a) and a reflective sidewall (60b), the curved rear reflector surrounding the processing portion of the light source system on a side opposite to the skin contact area of ​​the device, and the reflective sidewall being between the curved rear reflector and the skin contact area.

3. The device according to claim 2, wherein the curved rear reflector (60a) is a parabolic or partially parabolic reflector, and the sidewall is a tubular reflector.

4. The device according to any one of claims 2 to 3, wherein the light escaping opening or window (62) is positioned as follows: At the reflective sidewall; or At the edge of the curved rear reflector adjacent to the reflective sidewall.

5. The device according to any one of claims 1 to 4, wherein the processing section (T) and the analysis section (S) of the light source system share a common light source.

6. The device of claim 5, wherein the controller (70) is configured to control the common light source to provide a pre-flash, the pre-flash being used as the pigmentation analysis light prior to providing the processing light.

7. The device of claim 6, wherein the light source system includes a flash lamp, and the device includes a main capacitor device and a boost capacitor device for storing charge for delivering energy to the flash lamp, wherein the controller is configured to discharge the boost capacitor device to provide the pre-flash.

8. The device according to any one of claims 5 to 7, wherein the detector (D) includes a first detector region and a second detector region, each of the first detector region and the second detector region having an associated narrowband filter.

9. The device according to any one of claims 1 to 4, wherein the processing portion (T) of the light source system includes a first light source, and the analysis portion of the light source system includes a second light source (S), wherein the second light source (S) is positioned outside the reflective housing, and the reflective housing includes a light incident opening (66) for receiving the pigmentation analysis light from the second light source (S).

10. The device according to claim 9, wherein the second light source (S) comprises two light source elements of different wavelengths.

11. The device according to any one of claims 1 to 10, wherein the size and position of the light escaping opening or window (62) are such that light reflected from substantially the entire skin area to be processed by the device is directly projected onto the detector (D) through the light escaping opening or window (62).

12. The device according to any one of claims 1 to 11, further comprising a lens located at the light escaping opening or window.

13. The device according to any one of claims 1 to 12, wherein the light escaping opening or window (62) comprises an opening including a structured reflector for reflecting light directly received from the analysis portion of the light source system.

14. The device according to any one of claims 1 to 13, wherein (i) the positioning angle (γ) between the normal to the skin surface and (ii) the path from the center of the skin treatment area to the detector is greater than half the angle (τ) of the treatment beam incident on the skin in the same plane as the positioning angle (γ).

15. The device according to any one of claims 1 to 14, wherein the controller is configured to determine skin pigmentation according to: Analysis of two wavelengths of light used for skin pigmentation analysis; or Analysis of the light intensity of the skin pigmentation.

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