An optical radiation emitting handpiece

Abstract

The handpiece comprises an array of emitters, oriented to emit optical energy toward a region of epidermis to be treated. The handpiece further comprises a transparent element positioned in front of the array of emitters and through which, during use, optical energy emitted by the array of emitters and optical energy backscattered from the epidermis pass. A cooling device is adapted to remove heat from the region of epidermis during use. The cooling device comprises at least one cooling plate and a thermoelectric device, with a hot side and a cold side, interposed between the cooling plate and the transparent element.

Description

AN OPTICAL RADIATION EMITTING HANDPIECEDESCRIPTIONTECHNICAL FIELD

[0001] The present invention relates to the field of handpieces for the application of energy, in particular optical energy, for cutaneous or transcutaneous therapeutic or aesthetic treatments.BACKGROUND ART

[0002] In the medical and aesthetic field, the use of handpieces that emit optical radiation is known for a variety of applications and many purposes. These handpieces generally use optical sources, i.e., sources that emit an electromagnetic radiation in the visible, in the near-infrared or in the near-ultraviolet range. In some applications optical emission is generated by lamps and LEDs that emit incoherent light. In other applications laser sources, i.e., coherent light sources, are used. In some applications, the efficacy of the treatment with optical radiation is enhanced by combining it with muscle tissue mobilization (e.g. to obtain a lymph drainage or toning effect), obtainable through integration with suitable electrostimulation systems.

[0003] Recently, handpieces that use Vertical-Cavity Surface-Emitting Laser diodes, also known with the acronym VCSEL, which will be used also in this context, have been produced. An example of handpiece that uses VCSEL is disclosed in EP3219360. This handpiece has a complex and bulky structure and is hence difficult to use and costly. In particular, it is not suitable for applications in which the handpiece is fixed to the patient and remains in a stationary position relative to the patient for relatively long treatment times.

[0004] Devices and handpieces that integrate treatments with light radiation and muscle electrostimulation are also available on the market, but the footprint of the electrodes limits the dimensions of the window available for treatment with optical radiation. Moreover, the presence of electrodes means that the opposite poles of the device must not be positioned too close, to limit the risk of possible interferences and short-circuits. This requirement poses limits and constraints to the positioning of aplurality of devices for simultaneous treatment of the whole area of interest.

[0005] EP3219360 discloses a handpiece for laser skin treatment, comprising an array of VCSELs (Vertical Cavity Surface Emitting Lasers). The array of VCSELs is attached on a cooling block, inside which a cooling liquid circulates. A thermoelectric cooling device is arranged around the cooling block, with the cold in contact with a casing that surrounds the thermoelectric cooling device, the array of VCSELs and a space between the array of VCSELs and a front window made of an element transparent to the optical radiation emitted by the VCSELs. The window is in thermal contact with the casing. The thermoelectric cooling device removes heat from the front window, to cool the epidermis during the treatment. Cooling of the skin is not very efficient due to the long path the heat must take to be finally removed from the cooling fluid circulating in the cooling block. Moreover, the handpiece is very bulky.

[0006] Therefore, there is the need to provide a simpler and more compact handpiece, which can overcome or mitigate the problems of existing handpieces.SUMMARY

[0007] An applicator handpiece for dermatological treatments by means of optical radiation according to the present disclosure comprises an array of emitters, oriented to emit optical energy toward a region of epidermis to be treated. Moreover, the handpiece comprises a transparent element positioned in front of the array of emitters. The transparent element forms a window through which, during use, optical energy emitted by the array of emitters and optical energy backscattered from the epidermis pass. In the present context, “transparent” means an element that allows the passage of at least 80% of the power emitted by the emitters at the frequency (i.e., at the wavelength) of interest for the treatment, which can be the whole emission range of the emitters, or a sub-range of the emission spectrum.

[0008] As will be apparent from examples of application referred to below, dermatological treatment is generally meant as a treatment that takes place through the epidermis. Treatments in which the target tissue is subcutaneous, for example subcutaneous adipose layers, also fall within the definition of dermatological treatments, in the sense intended herein.

[0009] The handpiece further comprises a cooling device adapted to remove heat from the region of epidermis during use. Advantageously, the cooling device comprises at least one cooling plate, which can be arranged so that the array of emitters is positioned between the cooling plate and the transparent element. The cooling device further comprises a thermoelectric cooling device (TEC: ThermoElectric Cooler), with a hot side and a cold side, hereinafter for brevity also only “thermoelectric device”. The thermoelectric device, for example one or more Peltier cells in series and / or in parallel, is suitably interposed between the cooling plate and the transparent element. The hot side of the thermoelectric device is in heat exchange relationship with the cooling plate and the cold side is in heat exchange relationship with the transparent element.

[0010] In embodiments disclosed herein, the thermoelectric device forms a frame interposed between the cooling plate and the transparent element, defining between the cooling plate, the transparent element and the frame a space in which the array of emitters is housed. In this way, a particularly compact handpiece is obtained. In particular, the arrangement can be such that in a plan view in a direction orthogonal to the cooling plate and to the transparent element, the cooling plate and the transparent element have the same dimension. The frame formed by the thermoelectric device is advantageously contained within the plan footprint of the cooling plate and of the transparent element.

[0011] Advantageously, the cooling plate can have a thickness, i.e., a dimension in the direction parallel to the direction of propagation of the radiation from the emitters toward the transparent element, which is less than the two dimensions in the direction orthogonal to the direction of propagation. This helps to reduce the overall dimensions of the handpiece.

[0012] The cooling plate can be a component having a thickness less than the other dimensions (width and length, or diameter or axes, in the case of a circular or elliptical handpiece). The plate can be flat, however this is not essential. In some embodiments, the handpiece can be shaped to have an application surface that is not flat. In this case, the plate is also preferably shaped to follow the curvature of the application surface. The application surface is defined by the outer face of the transparent element.

[0013] The transparent element is also a plate element, i.e., having a smaller thickness compared to the other dimensions, i.e., width and length, or diameter or axes, in the case of a circular or elliptical handpiece. As indicated above, although in some applications the outer face of the transparent element is flat, and hence the transparent element is planar, this shape is not the only shape possible. Forms shaped with one or even two curvatures can be convenient in handpieces intended to treat given regions of the body, such as the face, the chin, the underside of the chin, the upper limbs (arms) and lower limbs (legs), the buttocks.

[0014] Hot side and cold side are meant as the sides, or faces, of the thermoelectric device that - in use, i.e., when the thermoelectric device is electrically powered - yield heat (hot side) and absorb heat (cold side).

[0015] For high efficiency, the hot side of the thermoelectric device is preferably in conduction heat exchange relationship with the cooling plate and the cold side of the thermoelectric device is in conduction heat exchange relationship with the transparent element.

[0016] Advantageously, the emitters comprise semiconductor lasers. In advantageous embodiments, the emitters comprise Vertical Cavity Surface Emitting Lasers (VCSELs), the technical characteristics of which have advantages of use in this context, which will be illustrated in more detail below.

[0017] The cooling plate can dissipate heat, for example, through fins and with an optional ventilation system, which can generate a gaseous flow, for example air, that flows over the fins and removes heat, advantageously through forced ventilation.

[0018] However, in preferred embodiments, heat is preferably removed from the cooling plate by means of a cooling circuit, adapted to circulate a cooling fluid in heat exchange with the cooling plate. For increased cooling efficiency, the cooling fluid can be a liquid, for example even simply water. The cooling circuit can comprise cooling fluid conduits inside the cooling plate, in this way obtaining more efficient heat removal. The cooling circuit can be interfaceable with a system for pumping and cooling the cooling fluid, which can be housed in a device with which the handpiece is interfaced.

[0019] For example, the cooling fluid conduits extend parallel to a face of the cooling plate facing the transparent element and on which the array of emitters is attached. The cooling fluid conduits can be joined to one another to form a single conduit or path, for example a serpentine, as described below.

[0020] To obtain more uniform, i.e., more homogeneous, irradiation, of the epidermis, a beam shaper, positioned between the array of emitters and the transparent element, can be provided inside the handpiece. In some embodiments, the beam shaper, for example a plate element, serves to shape the beams generated by the emitters increasing their angle of divergence, to obtain an irradiation of the epidermis with a more uniform power density.

[0021] In other embodiments, a beam shaper can be provided, having a function different than that of making the irradiation uniform or homogeneous. In fact, the beam shaper generally has the function of modifying the shape and the divergence of the beam of each emitter in order to obtain the desired spatial distribution for a specific application.

[0022] In this sense, the desired spatial distribution of the energy of the beam might not be uniform, or homogeneous, but, for example, characterized by areas of greater density and of lesser density, or even with no irradiation. A beam shaper can, for example, be configured to obtain a “fractional” application of the optical energy. In this case, the beam shaper can, for example, comprise microlenses or other features that, starting from the beam of the single emitter, generate small areas in which radiation is focused, surrounded by areas with no or much lower irradiation. In this case, a pattern of focused dots is obtained, surrounded by areas in which the radiation does not have any significant effect. A fractional distribution of this type can also be combined with timed control of the emissions of one or more emitters.

[0023] In yet other embodiments, the beam shaper can be configured so as to focus the beam emitted by the single emitter in a differentiated manner, for example to create regions that are spatially distributed according to a selectable pattern, where different areas are irradiated with different energy densities to achieve different effects on the treated tissue.

[0024] Further advantageous features of the handpiece are described below and defined in the appended claims.

[0025] A handpiece of the type described herein can be used, for example, for the applications indicated below; an advantageous set of emission parameters, particularly the wavelength, is indicated for each application:- hair removal: wavelength 700-1 lOOnm: energy density from 2-20J7cm2in 10- 100ms;- body sculpting: wavelength 800-1 lOOnm; power density 0.1-2W / cm2:- melasma treatment: wavelength 600-800 nm; energy density l-20J7cm2- psoriasis treatment: wavelength 300-400nm; power density: 10-50mW / cm2- musculoskeletal pain therapy: wavelength 800-1 lOOnm; energy density: 100- 800mJ7cm2, pulsed radiation with repetition frequency 10-40Hz and pulse duration 100-400ps- tissue shrinkage: wavelength 750-1 lOOnm; energy density: 5-65J / cm2- biostimulation treatments: wavelength 400-1800nm; power density 0.1 mW / cm2-lW / cm2- photodynamic therapy (PDT): wavelength 400-1800 nm; power density ImW / cm2- IW / cm2.BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The invention will be better understood by reference to the description and the accompanying drawings, which illustrate non-limiting exemplary embodiments of the invention. More in particular, in the drawing:Fig. l shows a sectional view along the line II-II of Fig.2, of a handpiece according to the present description;Fig.2 shows a section along II-II of Fig.l;Fig.3 shows a section along III-III of Fig. l;Fig.3A shows an enlargement of a detail of Fig.3;Fig.4 shows an enlargement of a portion of the transparent element of a beam shaper attached thereon;Fig.5 shows a front view of a handpiece provided with electrodes for electrostimulation,Fig.6 shows a partial section of a handpiece in a further embodiment; Fig.6A shows an enlargement of a portion of Fig.6;Fig.7 shows a partial section of a handpiece in a further embodiment;Fig.7A shows an enlargement of a portion of Fig.7;Fig.8 shows a section of a handpiece in a further embodiment;Fig.9 shows an exploded view of the handpiece of Fig.8;Fig.10 shows a section of a handpiece in a further embodiment; and Fig.10A shows an enlargement of the detail A of Fig.10.DETAILED DESCRIPTION

[0027] An embodiment of a handpiece according to the present disclosure is illustrated in Figs. 1 and 2. The handpiece is indicated as a whole with the reference 1. In the embodiment illustrated, the handpiece 1 has a flat shape. In other embodiments, the handpiece can have a curved shape, for example for treating some specific areas of the human body. A handpiece of the type disclosed herein can advantageously be used for treating subcutaneous adipose layers, by means of apoptosis of the adipose cells caused by the heat generated in the tissue treated as a result of irradiation with optical radiation. In this context, the handpiece may have a curved shape, and specifically with a concave application surface, to follow the profile of the limbs, of the underside of the chin or of other regions of the body.

[0028] Therefore, in the present disclosure the various components represented herein as having a planar extension, must be understood as being capable of being configured differently, and specifically with a simple curvature (to define cylindrical surfaces) or also with a double curvature.

[0029] Returning to the drawing, in the illustrated embodiment, the handpiece 1 has a plan extension of rectangular shape with dimensions LI and L2 (see Fig.2), and a thickness L3. Advantageously, the dimensions LI and L2 can be of the same order of magnitude. The dimension L3 is preferably substantially smaller than the smallest of the dimensions LI and L2. For example, L3 can be equal to 1 / 3, preferably 1 / 4, more preferably 1 / 5 or less, of the smaller of the dimensions LI, L2. The dimensional ratios indicated in the figure are not to scale.

[0030] The handpiece 1 comprises an array 3 of emitters. Reference number 5 indicates an assembly of emitters, each of which can comprise one or more laser diodes. For example, each emitter 5 may have a dimension L4 x L4 (see Fig.3A) and comprise a plurality of laser diodes. The emitters are supported by a support 7.

[0031] In advantageous embodiments, each emitter 5 can be a Vertical-Cavity Surface-Emitting Laser diode (for brevity VCSEL).

[0032] The use of VCSELs is particularly advantageous in this context. In fact, the emission of the VCSEL takes place “vertically”, i.e., in a direction perpendicular to the main surface (in the drawing the main surface is the surface of the support 7 on which the VCSELs are attached) and singularly. Moreover, the divergence of the beam output from the VCSELs is very narrow and easy to manage / modulate.

[0033] The VCSEL emitters are practically planar and of very small dimensions. For example, in the embodiment disclosed herein, each emitter 5 of the array 3 of emitters can comprise a chip of dimension L4 = 0.47 mm and comprise 113 VCSELs. In this way, for example, an array with emitters 5 at a mutual distance of a few millimetres from one another can be produced on a support with dimensions 8.5 x 5.5 x 0.5 cm, forming a module which in total can emit over 63 W. The value indicated are examples and must not be understood to be limiting.

[0034] Each VCSEL emits a laser beam that propagates from a first face 7A of the support 7, on which the emitters 5 are attached. The heat generated by the emitters 5 can be dissipated, i.e., removed, in the manner described below, from the second face 7B of the support 7, i.e., the face opposite the one on which the VCSELs forming the emitters 7 are attached.

[0035] The VCSELs emit at a narrow band wavelength which remains stable over temperature variations (drift in the order of 0.07 nm per °C), a characteristic that makes this type of emitters particularly suitable for medical applications.

[0036] The emission of the VCSELs is stable and efficient even at higher operating temperatures, such as 30-35°C, which do not shorten the useful life of the emitters.

[0037] In the illustrated embodiment, the support 7 is in contact with a rear coolingplate 9. In practical embodiments, the support 7 is in direct, or indirect, contact, i.e., mediated by interposition with a further intermediate element, with the cooling plate 9. Advantageously, regardless of whether the contact is direct or indirect, the contact is such as to ensure efficient heat exchange to dissipate heat from the support 7 to the cooling plate 9.

[0038] The cooling plate 9 forms part of a cooling device and can be provided with one or more heat dissipating elements. In one embodiment, the dissipating elements can comprise a cooling circuit for a cooling fluid, preferably a cooling liquid. In Figs.1 and 2 the cooling circuit comprises a conduit 11 with an inlet connection 11 A and an outlet connection 1 IB, through which the cooling circuit can be connected to a cooling system, not shown.

[0039] In advantageous embodiments, in addition to the cooling plate 9 the cooling device comprises one or more thermoelectric devices 13. In general, as understood herein, a thermoelectric device is a device adapted to perform a cooling function, i.e., of heat removal or transfer, using electrical energy. In some embodiments, the thermoelectric device or devices 13 can comprise one or more Peltier cells. Hereinafter, reference will be made without distinction to a single or to several Peltier cells, and it must be understood that the number of Peltier cells of the handpiece can be chosen according to construction and / or efficiency requirements. When more than one Peltier cell or other thermoelectric devices are provided, they can be arranged in series and / or in parallel with one another.

[0040] In the illustrated embodiment, the Peltier cells form a frame surrounding a space, inside which the array 3 of emitters 5 is arranged. A hot face or hot side 13 A of the Peltier cells is in heat exchange relationship with the cooling plate 9. In particular, the hot face 13 A of the Peltier cells 13 can be in direct contact with a face 9A, facing the inside of the handpiece 1, of the cooling plate 9. The support 7 can be attached directly on the face 9A, thus being in heat exchange relationship with the face 9A of the cooling plate. The reference 9B indicates the opposite face of the cooling plate 9, facing the outside of the handpiece.

[0041] The cold face, or cold side, indicated with 13B, of the Peltier cells is in contactwith a transparent element 15, positioned in front of the array 3 of emitters and of the cooling plate 9. The transparent element 15 may be in the form of a plate and defines the optical window of the handpiece, through which the radiation generated by the emitters exits. The term "transparent" means that the element 15 allows at least part of the radiation emitted by the emitters of the handpiece to pass through..

[0042] The transparent element 15 forms, together with the frame formed by the Peltier cells 13 and the cooling plate 9, an internal volume or inner space of the handpiece 1, in which the array 3 of emitters is housed. The transparent element 15 has a first face 15A facing the cooling plate 9 and toward the Peltier cells 13, and a second face 15B facing the outside. The face 15B is intended, in use, to be in contact with the epidermis of the patient.

[0043] Hot side and cold side, or hot face and cold face, of the Peltier cells are meant respectively as: the face or side that in use (i.e., when the Peltier cell is electrically powered) yields heat; and the face or side that in use absorbs heat.

[0044] As illustrated in the drawing, in a plan view in a direction orthogonal to the faces 9A, 9B of the cooling plate 9 and to the faces 15 A, 15B of the transparent element, the cooling plate 9 and the transparent element 15 have the same footprint, i.e., they have the same dimensions LI x L2. Likewise, the frame formed by the Peltier cells 13 has the same plan footprint LI x L2 and is entirely housed between the cooling plate 9 and the transparent element 15, so as to obtain a handpiece of very compact dimensions.

[0045] The transparent element 15 frontally closes the volume in which the array 3 of emitters is enclosed and is cooled by means of the cooling device comprising the Peltier cell or cells 13 and the cooling plate 9. In fact, the cold face 13B of the Peltier cells 13 cools the transparent element 15 and transfers heat, by means of the hot face 13 A, to the cooling plate 9. From the latter heat is removed by means of the cooling circuit 11.

[0046] As the heat is removed from the transparent element 15 along the perimeter area thereof, where the frame formed by the Peltier cell or cells is located, it is advantageous for the transparent element 15 to have a high thermal conductivitycoefficient. Moreover, to increase the efficiency of the handpiece and optimally exploit the optical emission generated by the emitters 5, it is advantageous for the transparent element 15 to have a high transmissibility in a wavelength range that comprises the whole emission spectrum of the emitters 5. If the emitters 5 emit at several wavelengths and the use of only one or more of these wavelengths, or sub-ranges of the whole emission range is desired, it would also be possible to use the transparent element 15 as filter, selecting the material of which it is composed so that it filters the undesired wavelengths.

[0047] In general, however, the transparent element 15 is preferably made of a material highly transparent to the emission spectrum of the emitters 5, as these preferably comprise sources with emission spectra that are appropriately centered on the wavelength required for the specific treatment for which the handpiece is intended.

[0048] A particularly suitable material for production of the transparent element 15 is synthetic sapphire, which is formed from a single crystal of aluminium trioxide (AI2O3). In fact, this material has a thermal conductivity of 35-40 Wm^K-1and a high transparency (greater than 80%) at the wavelengths of interest (between 300 nm and 4.5 pm).

[0049] In addition to high thermal conductivity and transparency at the wavelengths of interest for the medical application the handpiece is intended for, sapphire has other advantageous characteristics. It is biocompatible and can thus be applied directly on the epidermis, without the need to be provided with a surface coating layer. In the present context, “biocompatible” is meant as a material that complies with the requirements of the standard ISO 10993-1 :2018, in relation to what is applicable for materials classified as “Surface-contacting device in contact with intact skin for limited exposure (less than 24h)”.

[0050] Moreover, sapphire has a high hardness and abrasion resistance. This makes it suitable for this application, as it is not damaged by rubbing with the epidermis. Its high chemical resistance also means that it is not affected by secretions (sweat) of the epidermis, and by gels that are applied on the epidermis prior to treatment.

[0051] It must be understood that the transparent element 15 can also be made ofother materials having similar chemical-physical and optical performance, as such or when provided with a protective layer, for example to make them biocompatible.

[0052] Typically, alternative materials can be quartz, calcium fluoride, borosilicate glass.

[0053] In general, the materials that can be used preferably have a thermal conductivity equal to or greater than 10 Wnf'K’1, preferably equal to or greater than 30 Win 'K’1, even more preferably equal to or greater than 35 Wnt'K’1. Typically, the materials have a conductivity equal to or less than 2600 Wm^K’1.

[0054] In embodiments described herein, the transparent element 15, which forms the window through which the optical radiation generated by the emitters 5 is irradiated toward the epidermis of the patient, preferably has the following characteristics: thermal conductivity between 30 Wnt'K'1and 50 Wnt'K'1at the temperatures of use (typically 5-35°C, preferably 5-28°C); biocompatibility, i.e., the material complies with the requirements of the standard ISO 10993-1 :2018, in relation to what is applicable for materials classified as “Surfacecontacting device in contact with intact skin for limited exposure (less than 24h)”; optical transmissibility equal to or greater than 80% at the wavelength of interest emitted by the emitters 5; hardness equal to or greater than 4 GPa, for example between 4 GPa and 150 GPa; high chemical resistance to acids and bases (sweat or other bodily secretions, gels) and water solubility below 0.001 g / lOOg.

[0055] In the applications of greatest interest, the window is cooled to between 5 °C and 28 °C. However, the material used preferably has a high operating temperature threshold (>1000°C). This is due to the fact that in the presence of dirt particles or residues on the surface, the optical radiation could cause localized overheating or carbonization, with a localized temperature increase. In this case, with high resistanceto high temperatures it is possible to avoid breaking or shattering.

[0056] As mentioned, one or more of these characteristics can be given to a base material by applying a suitable surface coating on the outer face 15B thereof.

[0057] The emitters 5 can have a rather narrow emission angle. In particular, if the emitters 5 comprise VCSELs, these generally emit a beam with an opening of around 10°. By arranging the VCSELs according to an array 3 with a pitch of a few millimetres, for example 2-3 mm, the optical radiation incident on the epidermis, at the outer face 15B of the transparent element 15, may not be uniform and be concentrated in areas centred on the axes of the emitters 5. In some cases, this can be undesirable, for example when the handpiece 1 is used holding it stationary relative to the epidermis of the patient, instead of moving it more or less continuously.

[0058] To make the energy density incident on the epidermis uniform, in some embodiments one of the faces of the transparent element 15, and preferably the inner face 15 A, can be provided with a satin finish, i.e., machined to obtain a surface roughness adapted to obtain a suitable uniformity of the incident energy density. The roughness can be easily chosen based on the desired degree of uniformity to be reached.

[0059] However, treating the surface of the material of which the transparent element 15 is formed, to give it a satin finish, can be complicated and costly, in particular due to the high hardness and abrasion resistance of the transparent element 15, characteristics that are desirable for the reasons specified above. Moreover, satin finished surfaces limit the transmission of light.

[0060] Therefore, instead of or in combination with a satin-finished surface of the transparent element, the handpiece 1 can preferably comprise a beam shaper 17 positioned within the volume enclosed between the cooling plate 9, the Peltier cells 13 and the transparent element 15.. In practical embodiments, the beam shaper 17 can be placed in contact with the surface 15A of the transparent element 15, facing the array 3 of emitters. The beam shaper 17 can be any element that is adapted to expand the beam emitted by each emitter 5 so as to obtain a wider beam with a suitably uniform power density of the optical radiation. In advantageous embodiments, the beam shaper17 can shape the beam emitted by each emitter 5 so that the divergent beams that propagate from the beam shaper 17 toward the outer surface 15B of the transparent element 15 are superimposed on one another when they reach the epidermis in contact with the outer surface 15B.

[0061] In some embodiments, the beam shaper 17 is a plate element.

[0062] In particularly advantageous embodiments, the plate shaped beam shaper 17 can comprise a glass plate 19 (see enlargement of Fig.4) with a first face 19A facing the array 3 of emitters and a second face 19B facing the transparent element 15 and preferably in contact with the inner face 15A thereof.

[0063] A polymeric layer 21 can be attached on one of the two faces of the glass plate 19. Preferably, the polymeric layer 21 is attached on the first face 19A of the glass plate 19.

[0064] In some embodiments, microlenses are attached on one of the two faces of the glass plate 19, having the function of beam shaper in the same way as the polymeric layer 21. The microlenses can be produced on the surface of the glass plate 19, for example by means of etching, or can be obtained by applying a film.

[0065] The glass plate 19 and polymeric layer 21 together form a beam shaper of known type, such as polymer-on-glass.

[0066] As mentioned, in some embodiments the beam shaper performs the function of making the radiation that reaches the epidermis uniform, i.e., more homogenous. For this purpose, the beam shaper may primarily perform the function of expanding the beam.

[0067] However, it would also be possible for the beam shaper to perform a different function on the beam emitted by each emitter. For example, the beam shaper can focus the beam of each emitter in small points or spots with a high concentration of radiation, and consequently a high density, surrounded by areas with a low concentration, and consequently with a low (or zero) density. For this purpose, the beam shaper can, for example, comprise a micro- structure (with microlenses or similar) that focuses the radiation of a single beam in discrete points. Beam shapers of this type can be used fora fractional treatment, i.e., in which the energy is focused on single points or dots, arranged according to a predetermined pattern. It would also be possible to implement distributions of areas with a different density of radiation, to obtain variable effects on different areas of the surface targeted by the radiation coming from a single emitter.

[0068] In Fig. l, reference Fl shows a slightly divergent beam, for example with an opening angle of 10°, emitted by the emitters 5. Each beam Fl is shaped by the beam shaper 17 which increases the opening angle thereof. The reference F2 indicates each beam emerging from the beam shaper 17 and propagating through the transparent element 15. Each beam F2 can have a much larger opening than the opening of the beam Fl. For example, each beam F2 can have an opening between 20° and 120°, preferably between 60° and 100°, even more preferably between 80° and 95°. In this way, adjacent beams F2, emitted by adjacent emitters 5 of the array 3 of emitters overlap on the face 15B of the transparent element 15 and consequently on the epidermis, on which the handpiece 1 is positioned by means of the face 15B of the transparent element 15.

[0069] In some embodiments, a spacer 23 can be interposed between the array 3 of emitters and the beam shaper 17.

[0070] The spacer 23 can comprise a plurality of through holes or openings 25, aligned with the emitters 5, for passage of the light beams Fl emitted by the emitters 5. In advantageous embodiments, the transverse dimension of each opening 25 of the spacer 23, the thickness of the spacer, i.e., the dimension thereof in the direction of propagation of the radiation emitted by the emitters 5 of the array 3 of emitters, and the opening angle of each beam Fl emitted by the emitters 5 are preferably selected so that each beam Fl of optical radiation emitted by each emitter 5 propagates along the opening from the emitter toward the transparent element, without interfering with an inner surface of the respective opening in the spacer 23.

[0071] The spacer 23 prevents the beam shaper 17 from being too close to the emitters 5 and consequently prevents the risk of damaging the beam shaper 17 due to overheating. This is particularly useful when the beam shaper 17 comprises a polymeric layer 21.

[0072] In some embodiments, the spacer 23 can be made of a diffusing material. For example, the spacer 23 can be made of ceramic material or of a material having a polymer matrix containing ceramic material. For example, the ceramic material can comprise aluminium oxide, silicon oxide, zirconium oxide, silicon nitrite, titanium oxide, magnesium silicate hydrate, or combinations thereof.

[0073] The function of the diffusing material that the spacer 23 can be composed of is described below.

[0074] The operation of the above-described handpiece 1 is as follows. The handpiece is connectable to a base (not shown) that supplies power to the emitters 5 and to the thermoelectric devices 13, and cooling fluid to the cooling plate 9. In use, the handpiece 1 is positioned with the outer face 15B of the transparent element 15 in contact with the epidermis of the patient in the area to be treated. Optical coupling between the handpiece 1 and the epidermis of the patient can be obtained or improved with a suitable gel, commonly used for these purposes, applied on the area to be treated.

[0075] By activating the emitters 5 of the array 3 of emitters, the handpiece generates optical beams Fl directed toward the patient. The beams Fl are shaped by means of the beam shaper 17, so that an optical radiation with approximately uniform power density is applied on the portion of epidermis in contact with the outer face 15B of the transparent element 15.

[0076] The photons of radiation emitted toward the patient penetrate the epidermis and can reach the underlying tissues, for example the adipose layer below the epidermis. During treatment, overheating of the epidermis is avoided thanks to cooling obtained by the cooling device comprising the Peltier cells 13 and the cooling plate 9, wherefrom heat removed from the epidermis and from the array 3 of emitters is extracted from the handpiece by circulating cooling fluid in the conduit 11 of the cooling circuit.

[0077] A part of the optical radiation is back-scattered from the epidermis toward the handpiece. If the handpiece 1 contains a spacer 23 made of diffusing material, the back- scattered photons that reach the diffusing material of the diffusing componentformed by the spacer 23 are back-scattered again in the opposite direction toward the epidermis.

[0078] It has been found, and forms one of the novel aspects of the handpiece described herein, that the use of a diffusing material to recover the back-scattered radiation coming from the epidermis is surprisingly more advantageous than the use of a reflecting material, as used in prior art handpieces. In fact, according to a first aspect, the use of a diffusing material avoids the need to produce reflecting surfaces, which are very costly to obtain. Moreover, the reflecting surfaces recover and reflect toward the epidermis only incident photons according to small angles relative to the direction orthogonal to the reflecting surface.

[0079] Vice versa, the diffusing material, above all if of suitable thickness, for example between 1 mm and 15 mm, preferably between 1.2 and 9 mm, for example between 1.5 and 5 mm, collects and returns by back-scattering toward the epidermis a much greater quantity of photons, without the need for particular surface finishes. Thicknesses of the above-indicated order of magnitude are chosen so that the photons back- scattered from the epidermis follow sufficiently long paths in the diffusing material to increase the probability of being back-scattered toward the epidermis rather than passing through the diffusing material on the side opposite to the window formed by the transparent element 15.

[0080] As a result, higher efficiency is achieved compared to handpieces with reflective surfaces, at lower manufacturing cost. However, it is also possible to produce diffusing layers with materials normally used for reflecting coatings or treatments. In some embodiments, for example, the diffusing material is produced by means of deposition of a thin metal layer, with an opaque finish, on the surface of the array of emitters, with a thickness between lOOnm and 10pm. An embodiment of this type will be described below.

[0081] The use of emitters in the form of VCSELs (which have a small numerical opening) allows the thickness of the spacer and hence back-scattering, to be increased, as the active volume increases.

[0082] In some embodiments, electrodes can be produced on the outer face or surface15B of the transparent element 15. The combination of muscle contraction electrostimulation with optical radiation is interesting for a series of clinical reasons. Moreover, this combination increases the efficacy of the treatments, above all in applications for reducing body fat and for body sculpting. Typically, two electrodes can be provided, formed by vacuum deposition of an electrically conductive layer, preferably at least partially transparent to the radiation emitted by the emitters used in the handpiece. The electrodes can be positioned in front of the frame formed by the Peltier cells 13, as indicated schematically with the reference 31 in Fig.5, which shows an exemplary embodiment of electrodes 31 in a front view of the handpiece. The production of transparent electrodes, deposited directly on the contact surface, allows optimization of the shape, dimension and position of the electrodes on the interface between device and tissue, without interfering with the optical radiation emission window. The production of transparent electrodes of this type also facilitates the positioning of several handpieces close to one another, minimizing the risk of electrical interference between them. The electrodes 31 can be used to apply an electromagnetic field, for example in radiofrequency, during the treatment with optical beams generated by the emitters 5, to obtain a different or greater treatment efficacy.

[0083] The electrodes can be made of indium tin oxide or polyaniline, for example.

[0084] In the embodiments described above, to optimize the heat exchange between the thermoelectric device 13 and the cooling plate 9, and between the thermoelectric device 13 and the transparent element 15, forming the optical window of the handpiece, brazed joints can be provided. For example, the thermoelectric device 13 can be brazed to the cooling plate 9 and the optical window formed by the transparent element 15 can be brazed on the thermoelectric device. To braze the transparent element 15 forming the optical window, a metal coating (for example made of aluminium and silver, or aluminium and gold) can be deposited on its frame, i.e., on the perimeter area of its surface facing the thermoelectric device 13, which is then brazed on the thermoelectric device 13. A layer of aluminium is present on the ceramic layer of the thermoelectric device 13. In this way, the thermal resistance between the window and the cold side of the thermoelectric device is minimized. Moreover, the handpiece is much more compact, in particular thinner, as it has no fastening screws.

[0085] The embodiment shown in Fig.l comprises a spacer 23 having holes or openings 25 for the passage of the beam emitted by each emitter 5 of the array 3. The spacer is made of ceramic material to provide a diffusing function of the radiation back- scattered from the skin during treatment.

[0086] In other embodiments, a thinner spacer, having a function of reflecting rather than diffusing the back-scattered radiation, can be provided. An embodiment of such a handpiece is illustrated in Fig.6, which shows only a portion of an array 3 of emitters 5 and a spacer positioned in front of the array of emitters. The spacer is again indicated with the reference 23. The spacer 23 has a surface 23 A facing the emitters 5 and a surface 24B facing the optical window formed by the transparent element 15 (not shown in Fig.6). The spacer 23 can be formed in this case by a glass plate or other material transparent to the radiation emitted by the emitters 5 (beams Fl).

[0087] The surface 23A facing the emitters 5 is preferably provided with an anti- reflective coating layer, shown schematically in the enlargement of Fig.6A and indicated with SI. Similarly, the surface 23B facing the optical window formed by the transparent element 15 is coated with a layer of anti -reflective material S2. The anti- reflective layers SI and S2 are transparent to the radiation emitted by the emitters 5. A layer S3 of reflecting material is deposited on the anti -reflective layer S2. This layer S3 of reflecting material has the function of reflecting the radiation (beam F2) back- scattered from the epidermis. At the emitters 5 the reflecting layer S3 has interruptions I to allow the beams of electromagnetic radiation Fl generated by the emitters 5 to pass through.

[0088] The glass plate forming the spacer 23 can be thin, for example with a thickness of less than 1 mm, typically 0.1-0.5 mm and act mainly as a support for the reflecting layer S3.

[0089] A further embodiment is illustrated in Fig.7, which, similarly to Fig.6, only shows a portion of the array 3 of reflecting elements 5 and a portion of a spacer 23. The same reference numbers indicate parts identical or corresponding to those described with reference to Fig.6. In this exemplary embodiment, the spacer 23 is made of ceramic material which can be easily perforated to produce through openings infront of the emitters 5. Similarly to Fig.1, in Fig.7 the through openings are indicated with the reference 25. The surface 23 A of the spacer 23 facing the emitters 5 has no layer deposited thereon, while a layer S3 of reflecting material is provided on the surface 23B facing the optical window formed by the transparent element 15, to reflect the radiation back-scattered from the skin during the treatment, similarly to the reflecting layer S3 of Fig.6.

[0090] The embodiments described above are characterized by a particularly compact structure, which allows the production of handpieces of particularly low thickness L3, typically equal to or less than 3 cm, preferably equal to or less than 2 cm. This characteristic, combined with plan dimensions LI, L2 equal to multiples of L3, allows the production of handpieces of flat shape which can be applied, also more than one and combined with one another, in static positions relative to the body of the patient to be treated. This allows prolonged treatments to be performed without the need to move the handpieces and hence without requiring the permanent presence of personnel.

[0091] Figs.8 and 9 show a further embodiment in which the handpiece has a greater thickness and which can be advantageously used, for example, in dynamic applications, i.e., in which the handpiece requires to be moved during treatment. Fig. 8 is a longitudinal section and Fig.9 is an exploded view of the handpiece.

[0092] The handpiece of Figs.8 and 9 is indicated as a whole with the reference 101 and comprises an emitter module 103 containing an array of emitters 105, for example in the form of semiconductor lasers or of LEDs, shown only schematically in Fig.9. The array of emitters is positioned in front of a transparent element 115, for example formed by a sapphire plate, or of similar material, as described with reference to Figs. 1 to 4. In this embodiment, the plate of transparent material 115, which forms the optical window of the handpiece 101, is contained in a frame made of thermally conductive material, for example a metal. The frame is indicated with 117 and has a front surface 117A that surrounds the transparent plate or element 115, and a preferably flat back surface 117B. The back surface 117B is in thermal contact with a cold side of a thermoelectric device 119, for example a Peltier cell. The hot side of the thermoelectric device 119 is in thermal contact with a cooling plate 121. In contrast tothe previously described embodiments, in Figs. 8 and 9 the cooling plate 121 is centrally open and also forms a frame, indicated with 121C, in the thickness of which a cooling conduit 123 extends, adapted to remove heat transferred from the thermoelectric device 119 to the cooling plate 121.

[0093] The cooling plate 121 has an appendage 121 A on which the emitter module 103, which contains the array of emitters 105, is mounted. The emitter module 103 is in thermal contact with the cooling plate 121 and more particularly with the appendage 121A of the cooling plate.

[0094] In mounted arrangement (Fig.8) and during use, a cooling fluid circulating in the cooling conduit 123 removes heat generated by the emitter module 103 and by the hot side of the thermoelectric device 119. The latter cools the epidermis and the transparent element 115 by heat exchange through conduction with the frame 117,

[0095] The handpiece 101 further comprises a spacer 131, which can have an approximately hollow parallelepiped shape and which can be housed in the frame 117, between the transparent plate or element 115 and the emitter module 103, passing through the thermoelectric device 119 and the frame portion 121C formed at the cooling plate 121.

[0096] In practice, the spacer 131 forms a cavity through which the beams of electromagnetic radiation generated by the emitters 105 travel, which from the emitter module 103 reach the epidermis passing through the plate formed by the transparent element 115.

[0097] Advantageously, the spacer 131 is formed of a diffusing material, for example a ceramic material, or a resin loaded with powders of ceramic material. The function of the spacer 131 and of the cavity formed therein is to collect the radiation back- scattered from the epidermis and to convey it, by diffusion, back toward the epidermis. In this way, the back-scattered radiation is recovered and redirected toward the epidermis through the optical window formed by the transparent element 115. In some cases, the back-scattered radiation conveyed by diffusion from the diffusing material toward the epidermis can provide a very high contribution compared to the radiation which from the emitters 105 reaches the epidermis directly.

[0098] To obtain suitable control of the conditions of irradiation of the epidermis, in advantageous embodiments a photodetector, indicated schematically in Fig. 8 with reference 133, is associated with the volume between the emitters and the transparent element 115. Preferably, the photodetector is facing into a chamber between the array of emitters, the transparent element and the spacer 131. In this way, the photodetector is oriented so that it does not directly receive radiation back-scattered from the skin coming through the transparent element and does not directly receive radiation emitted by the emitters 105. The intensity of the optical radiation detected by the photodetector 133 is proportional, based on an experimentally determined constant of proportionality and a function both of the phototype of the skin and of the geometry of the chamber into which it faces, to the total optical energy delivered to the skin, both through direct radiation, and through radiation back-scattered from the diffusing material of which the spacer 131 is formed.

[0099] A photodetector of the type described and positioned as indicated above can also be used in the other embodiments described herein.

[0100] A further embodiment of a handpiece according to the present invention is shown in Fig.10. The same numbers indicate the same or corresponding parts to those already described with reference to the preceding figures. The handpiece is indicated as a whole with the reference 1. In the embodiment shown in Fig.10, the handpiece 1 has flat shape. In other embodiments, the handpiece can have a curved shape, for example to treat some specific areas of the human body. A handpiece of the type described here can be advantageously used for the treatments already mentioned above.

[0101] The handpiece 1 comprises an array 3 of emitters. Reference 5 indicates the emitters, each of which can comprise one or several laser diodes.

[0102] In advantageous embodiments, each emitter 5 can be a Vertical-Cavity Surface-Emitting Laser diode (for brevity VCSEL).

[0103] The use of VCSELs is particularly advantageous in this context for the reasons already specified above.

[0104] The VCSEL emitters are practically planar and have very small dimensions. For example, in the embodiment described here, each emitter 5 of the array 3 of emitters can comprise a chip measuring 0.5 x 0.5 mm and comprise 100 VCSELs. In this way, for example, an array with emitters 5 spaced a few millimetres apart, forming a module that as a whole can deliver more than 60 W, can be manufactured on a support measuring 8.5 x 5.5 x 0.5 cm.

[0105] The array 3 of emitters 5 can be formed on a metallization layer 201, attached on a substrate made of a thermally conductive and electrically insulating material. The metallization layer 201 is divided into conductive strips by means of gaps, one of which is shown in Fig.10A and indicated with the reference 202, in order to correctly supply the single emitters 5 of the array 3, according to a known technique.

[0106] The metallization layer 201 can be formed by a layer of gold or other metal material suitable for the purpose. The outer surface, i.e., the surface opposite the substrate 203, of the metallization layer 201, is diffusing and can have a thickness between lOOnm and 10pm, but it must be understood that these values are by way of example and not limiting.

[0107] The substrate 203, on which the metallization layer 201 is deposited (for example by vacuum metallization), has good electrical insulation properties, to insulate the array 3 from a cooling plate behind it, described below, but is thermally conductive, to dissipate the heat generated by the emitters 5 toward the cooling plate behind it. The substrate 203 can be made, for example, of silicon nitride or of another thermally conductive and electrically insulating material, such as ceramic.

[0108] The substrate 203 can in turn be attached on a supporting plate 205, for example made of copper or another good heat conducting metal. The supporting plate 205 can be interposed between the substrate 203 and the aforesaid cooling plate, indicated with 9 as in Fig.l. In other embodiments, the substrate 203 can be attached directly on the cooling plate 9.

[0109] Each emitter 5 emits a laser beam Fl that propagates toward an output side of the optical radiation, as specified below. The heat generated by the emitters 5 can be dissipated, by means of the cooling plate 9, due to the good thermal conductivityproperties of the metallization layer 201, of the substrate 203, of the supporting plate 205 (if present), and of the cooling plate 9.

[0110] The cooling plate 9 forms part of a cooling device and can be equipped with one or more heat dissipating elements. In an embodiment, the dissipating elements can comprise a cooling circuit for a cooling fluid, preferably a cooling liquid. In Fig.10, similarly to Fig.1, the cooling circuit comprises a conduit 11 with an inlet connection 11A and an outlet connection 11B (see Fig.2), through which the cooling circuit can be connected to a cooling system, not shown.[oni] In advantageous embodiments, in addition to the cooling plate 9 the cooling device comprises one or more thermoelectric devices 13. In general, in the sense used herein, a thermoelectric device is a device adapted to perform a cooling function, i.e., of heat removal or transfer, using electrical energy. In some embodiments, the thermoelectric device or devices 13 can comprise one or more Peltier cells. Hereinafter, reference will be made without distinction to a single or to several Peltier cells, and it must be understood that the number of Peltier cells of the handpiece can be chosen according to construction and / or efficiency requirements. When more than one Peltier cells or other thermoelectric devices are provided, they can be arranged in series and / or in parallel with one another.

[0112] In the illustrated embodiment, the Peltier cells form a frame that surrounds a space inside which the array 3 of emitters 5 is arranged. A hot face or hot side 13 A of the Peltier cells is in heat exchange relationship with the cooling plate 9. In particular, the hot face 13 A of the Peltier cells 13 can be in direct contact with a face 9A, facing the interior of the handpiece 1, of the cooling plate 9. The reference 9B indicates the opposite face of the cooling plate 9, which is oriented toward the outside of the handpiece.

[0113] The cold face, or cold side, indicated with 13B, of the Peltier cells is in contact with a transparent element 15, positioned in front of the array 3 of emitters and of the cooling plate 9. The transparent element 15 can be in the form of a plate and defines the optical window of the handpiece, through which the radiation generated by the emitters exits. The term “transparent” means that the element 15 allows the passage ofat least a part of the radiation emitted by the emitters of the handpiece.

[0114] The transparent element 15, together with the frame formed by the Peltier cells 13 and the cooling plate 9, forms an internal volume or internal space of the handpiece 1, in which the array 3 of emitters is housed. The transparent element 15 has a first face 15A facing the cooling plate 9 and the Peltier cells 13, and a second face 15B facing the outside. The face 15B is intended, in use, to be in contact with the epidermis of the patient.

[0115] As shown in the drawing, in a plan view in a direction orthogonal to the faces 9 A, 9B of the cooling plate 9 and to the faces 15 A, 15B of the transparent element, the cooling plate 9 and the transparent element 15 have the same footprint, i.e., they have the same dimensions LI x L2. Similarly, the frame formed by the Peltier cells 13 has the same plan footprint LI x L2 and is completely housed between the cooling plate 9 and the transparent element 15, so as to obtain a handpiece of very compact dimensions.

[0116] The transparent element 15 frontally closes the volume in which the array 3 of emitters is enclosed and is cooled by means of the cooling device comprising the Peltier cell or cells 13 and the cooling plate 9. In fact, the cold face 13B of the Peltier cells 13 cools the transparent element 15 and transfers heat, by means of the hot face 13 A, to the cooling plate 9. Therefrom the heat is removed by means of the cooling circuit 11.

[0117] As the heat is removed from the transparent element 15 along the perimeter area thereof, where the frame formed by the Peltier cell or cells is located, it is advantageous for the transparent element 15 to have a high thermal conductivity coefficient. Moreover, to increase the efficiency of the handpiece and optimally exploit the optical emission generated by the emitters 5, it is advantageous for the transparent element 15 to have a high transmissibility in a wavelength range that comprises the whole emission spectrum of the emitters 5. Suitable materials for producing the transparent element 15 have been described above with reference to Fig.1, together with other chemi cal -physical properties that it is advantageous for the transparent element 15 to have, such as biocompatibility, hardness and chemical resistance.

[0118] In order to make the energy density incident on the epidermis uniform, in some embodiments, one of the faces of the transparent element 15, and preferably the inner face 15 A, can have a satin finish. However, as mentioned with reference to Fig. 1, treating the surface of the material of which the transparent element 15 is composed in order to give it a satin finish can be complicate and costly, in particular due to the high hardness and abrasion resistance of the transparent element, 15, characteristics that are desirable for the reasons specified above. Moreover, satin finished surfaces limit the transmission of light.

[0119] Preferably, therefore, instead of a satin finished surface of the transparent element, or in combination therewith, the handpiece 1 can comprise a beam shaper 17 positioned inside the enclosed volume between the cooling plate 9, the Peltier cells 13 and the transparent element 15. In practical embodiments, the beam shaper 17 can be placed in contact with the surface 15A of the transparent element 15, facing the array 3 of emitters. The beam shaper 17 can be any element that is adapted to expand the beam emitted by each emitter 5 to obtain a wider beam with a suitably uniform power density of the optical radiation. In advantageous embodiments, the beam shaper 17 can shape the beam emitted by each emitter 5 so that the divergent beams that propagate from the beam shaper 17 toward the outer surface 15B of the transparent element 15 are superimposed on one another when they reach the epidermis in contact on the outer surface 15B.

[0120] In some embodiments, the beam shaper 17 is a plate element. For example, the flat shaped beam shaper 17 can comprise a glass plate 19 (similarly to what is shown in the enlargement of Fig.4) with a first face 19A facing an array 3 of emitters and a second face 19B oriented toward the transparent element 15 and preferably in contact with the inner face 15A thereof. A polymeric layer 21 can be attached on one of the two faces of the glass plate 19. Preferably, the polymeric layer 21 is attached on the first face 19A of the glass plate 19. The assembly of glass plate 19 and polymeric layer 21, forms a beam shaper of the type known as polymer-on-glass. As mentioned for other embodiments described herein, the beam shaper can alternatively comprise a layer of microlenses. These can be produced by materials applied to the glass plate 19, or by etching of the plate.

[0121] The beam shaper can have the function of making the radiation incident on the epidermis uniform. However, as mentioned above in the previous exemplary embodiments, the beam shaper could also have different functions, for example of implementing a fractional treatment, with the energy focused in points or dots.

[0122] In Fig.10 the reference Fl shows a slightly divergent beam, for example with an opening angle of 10°, emitted by the emitters 5. Each beam Fl is shaped by the beam shaper 17, which increases the opening angle thereof. Reference F2 indicates each beam emerging from the beam shaper 17 and propagating through the transparent element 15. Each beam F2 can have a much greater opening than the opening of the beam Fl. For example, each beam F2 can have an opening between 20° and 120°, preferably between 60° and 100°, even more preferably between 80° and 95°. In this way, adjacent beams F2, emitted by adjacent emitters 5 of the array 3 of emitters overlap on the face 15B of the transparent element 15 and consequently on the epidermis, on which the handpiece 1 is positioned by means of the face 15B of the transparent element 15.

[0123] In the embodiment of Fig.10 transparent electrodes 31, as described previously, are again provided.

[0124] Therefore, the embodiment of Fig.10 differs from the embodiment of Fig.1, mainly due to the absence of the spacer 23 and hence the absence of the diffusing effect of the ceramic material of which the spacer 23 is formed. However, the diffusing property of the exposed surface of the metallization layer 201 makes it possible to obtain a good back-scattering effect of the radiation, which being incident on the epidermis, is back- scattered therefrom toward the inside of the handpiece.

[0125] Although not indicated, also in the embodiment of Fig.10 a photodetector similar to the photodetector 133 can be provided, positioned as described previously to detect the optical radiation inside the volume between the emitters and the transparent element.

Claims

Claims1. An applicator handpiece for dermatological treatments by means of optical radiation, wherein the handpiece comprises: an array of emitters, oriented to emit optical energy toward a region of epidermis to be treated; a transparent element positioned in front of the array of emitters and through which, during use, optical energy emitted by the array of emitters and optical energy backscattered from the epidermis pass; a cooling device adapted to remove heat from the region of epidermis during use; wherein the cooling device comprises: at least one cooling plate; and a thermoelectric device, with a hot side and a cold side, interposed between the cooling plate and the transparent element, the hot side being in heat exchange relationship with the cooling plate and the cold side being in heat exchange relationship with the transparent element, wherein the thermoelectric device forms a frame interposed between the cooling plate and the transparent element defining, between the cooling plate, the transparent element and the frame, a space in which the array of emitters is housed.

2. The handpiece of claim 1, wherein the frame formed by the thermoelectric device is in direct contact with at least one of: said transparent element, and said cooling plate.

3. The handpiece of claim 1 or 2, wherein in a plan view in a direction orthogonal to the cooling plate and to the transparent element, the cooling plate and the transparent element have the same size; and wherein the frame formed by the thermoelectric device is contained within the plan footprint of the cooling plate and of the transparent element4. The handpiece of one or more of the preceding claims, wherein the array of emitters is arranged between the cooling plate and the transparent element, or in a seat formed in the cooling plate, in conduction heat exchange contact with thecooling plate.

5. The handpiece of any one of the preceding claims, wherein the frame formed by the thermoelectric device surrounds a support on which the array of emitters is mounted.

6. The handpiece of any one of the preceding claims, comprising at least one of the following features: the hot side of the thermoelectric device in direct contact and in conduction heat exchange relationship with the cooling plate; the cold side of the thermoelectric device is in direct contact and in conduction heat exchange relationship with the transparent element.

7. The handpiece of any one of the preceding claims, wherein the emitters are selected from the group comprising: semiconductor lasers, laser diodes, vertical cavity surface-emitting lasers (VCSEL).

8. The handpiece of any one of the preceding claims, comprising a cooling circuit adapted to circulate a cooling fluid in heat exchange with the cooling plate.

9. The handpiece of claim 8, wherein the cooling circuit comprises cooling fluid conduits inside the cooling plate.

10. The handpiece of claim 9, wherein the cooling fluid conduits extend parallel to a face of the cooling plate facing the transparent element and on which the array of emitters is attached.

11. The handpiece of any one of the preceding claims, further comprising a beam shaper positioned between the array of emitters and the transparent element.

12. The handpiece of claim 11, wherein the beam shaper is a plate element or a layer of microlenses.

13. The handpiece of claim 12, wherein the beam shaper comprises a glass plate with a first face and a second face, and a layer of polymeric material, or a layer of microlenses, attached on the first face.

14. The handpiece of any one of claims 11 to 14, wherein the first face of the glass plate is oriented toward the array of emitters and the second face of the glass plate is oriented toward the transparent element.

15. The handpiece of one or more of claims 11 to 14, wherein the beam shaper is in contact with a face of the transparent element facing the array of emitters.

16. The handpiece of claim 11, wherein the beam shaper comprises a satin finish surface of the transparent element.

17. The handpiece of one or more of claims 11 to 16, comprising a spacer between the array of emitters and the beam shaper.

18. The handpiece of claim 17, wherein the beam shaper is in contact with a face of the spacer facing the transparent element.

19. The handpiece of any one of the preceding claims, further comprising a component made of diffusing material positioned between the array of emitters and the transparent element; wherein the component made of diffusing material has a plurality of openings for the passage of light beams emitted by the emitters; and wherein the component made of diffusing material is adapted to collect optical radiation backscattered from the epidermis during the treatment and to diffuse the backscattered radiation collected toward the transparent element.

20. The handpiece of claim 19, wherein the transverse size of each opening of the component made of diffusing material, the thickness of the diffusing material in the direction of propagation of the radiation emitted by the emitters of the array of emitters, and an opening angle of each beam emitted by the emitters are selected so that each optical radiation beam emitted by each emitter propagates alongthe opening from the emitter toward the transparent element without interfering with an inner surface in the respective opening of the component made of diffusing material.

21. The handpiece of one or more of claims 19 or 20, wherein the component made of diffusing material has a thickness of at least 1 mm, preferably between 1 mm and 15 mm, more preferably between 1.2 and 9 mm.

22. The handpiece of any one of claims 19 to 21, wherein the component made of diffusing material consists of a ceramic material or a polymeric resin containing at least one ceramic material.

23. The handpiece of claim 22, wherein the ceramic material is selected from the group comprising: aluminium oxide, silicon oxide, zirconium oxide, silicon nitrite, titanium oxide, magnesium silicate hydrate, or combinations thereof.

24. The handpiece of any one of the preceding claims, wherein the array of emitters is associated with a layer of diffusing material configured to diffuse optical radiation backscattered from the epidermis toward the transparent element.

25. The handpiece of claim 24, wherein the layer of diffusing material comprises a metallization layer, applied on a thermally conductive and electrically insulating substrate; wherein the emitters are attached on a free diffusing surface, of the metallization layer, opposite the thermally conductive and electrically insulating substrate; and wherein the thermally conductive and electrically insulating substrate is in heat exchange relationship with the cooling plate.

26. The handpiece of claim 25, wherein the diffusing material has a thickness between lOOnm and 10pm.

27. The handpiece of any one of the preceding claims, comprising stimulation electrodes, deposited on an outer surface of the transparent element.

28. The handpiece of claim 27, wherein the stimulation electrodes are made of a material at least partly transparent to an emission wavelength of the emitters.

29. The handpiece of any one of the preceding claims, comprising a photo-detector that faces into a chamber comprised between the array of emitters and the transparent element; wherein the photo-detector is oriented so that it does not directly receive radiation backscattered from the skin passing through the transparent element and does not directly receive radiation emitted by the emitters.

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