WO2005110266A2

WO2005110266A2 - A device for dermatological treatment using light

Info

Publication number: WO2005110266A2
Application number: PCT/IB2005/051520
Authority: WO
Inventors: Michiel E. Roersma; Astrid Van Rij; Antonius M. Nuijs
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2004-05-13
Filing date: 2005-05-10
Publication date: 2005-11-24
Also published as: WO2005110266A3

Abstract

The present invention relates to a device (1) for optical treatment of human skin, comprising a housing (2) with a radiation source (4), an emission window (8) and a treatment fluid container (10, 26) with a release opening (16, 32). The device further comprises a fluid applicator (20, 22), which applies a controlled amount of treatment fluid (12) onto the skin, close to the emission window (8). The amount may be controllable, e.g. through use of a valve (18, 34). The device will reliably apply treatment fluid close to the skin that is (being) treated. This ensures that the skin receives a correct amount of fluid, and may also allow a visual check on whether or not a part of the skin has been treated. This is important for treatments that do not give immediate results, but may damage the skin by an overdose of radiation. Examples are photodepilation and photorejuvenation.

Description

A device for dermatological treatment using light

The invention relates to a device for treatment of human skin using optical radiation, comprising a housing with a source of optical radiation and an emission window defining a treatment area on a skin to be treated, a container for a treatment fluid, and a release opening adjacent to or opening into the emission window for releasing treatment fluid onto the skin.

A device for treatment of human skin as mentioned in the opening paragraph is known from US Patent No. 6 497 702. The known device is a probe for skin treatment. The probe comprises cavities with inductor elements for applying an electromagnetic field, as well as a laser source that emits via an opening. A conducting gel may be applied to the skin or into the cavities to establish a conductive interface between the probe and the skin to be treated. A problem associated with this known device is that correct application of the conducting gel, or any other treatment fluid to be applied onto the skin, is not ensured. In many cases it is important to apply a certain material onto the skin, such as conductive gel in the case of the known device. Other examples are a gel to promote optical coupling between the emission window and the skin or to carry off heat from the skin, or to apply a depilation promoting agent, or a skin aftertreatment product, etc. Furthermore, it is important that all of the skin (to be) treated receives a correct amount of material. Often, too little material reduces its effectiveness, while too much material is a simple waist. In the above-mentioned known device, the required material is either applied by hand, which is inconvenient for the user, or is applied in cavities in the probe, which makes application of the substance a chance event. Note that in this device it is not required to actually release the material, as long as a conductive contact is established. In any case, it is not possible to control the release of the material onto the skin. It is an object of the present invention to provide a device of the kind mentioned in the preamble, wherein the application of a treatment fluid or additive onto a skin to be treated is reliably facilitated. In order to achieve this object, a device for treatment of human skin in accordance with the invention is characterized in that the device further comprises a fluid applicator that is constructed to release a predetermined amount of the treatment fluid from the container onto the skin. By providing a fluid applicator of this kind, application of the treatment fluid onto the skin is facilitated, since manual application onto the skin or into cavities before every treatment is no longer required. Furthermore, since the treatment fluid is released through a release opening which is present adjacent to or opens into the emission window, every part of the skin that is or has been irradiated has been treated and marked by the treatment fluid. This offers a reliable feedback for the person operating the device, as to which part of the skin has been treated. For certain types of treatment devices this is very important, as will be shown further below. Moreover, since the fluid applicator will release a predetermined amount of treatment fluid, the person treated with the device will not be exposed to too high or too low a dose of the treatment fluid. The term "predetermined amount" relates to the fluid applicator applying a certain amount of treatment fluid every time it is applied to the skin. This may in turn relate to a certain layer thickness or other aspects, depending on the actual type of application. Preferably, the predetermined amount is controllable, so that it may be adjusted to the actual type of active ingredient(s), to the skin type or other physical properties of the person being treated, etc. For this purpose , the fluid applicator may be provided with any dose control means, such as a controllable valve In the present application, a window encompasses not only an opening, e.g. in the housing, but also a transmissive plate. It is remarked here that, if desired, more than one emission window may be provided. Furthermore, the term "adjacent" has its usual meaning of neighbouring, comprising not only touching (i.e. directly next to) but also sufficiently near to ensure a correct functioning of the device. In particular, this means that the distance between the emission window and the release opening should preferably not exceed about 1 cm, although this distance depends on the kind of treatment. E.g. for depilation, this distance preferably equals an average hair-to-hair distance on the treated skin of, say, about 5 mm. Nevertheless, if desired, this distance may be larger. "Optical radiation" is intended to mean visible radiation and the neighbouring parts of the infrared and ultraviolet spectral regions, roughly between about 300 nm and 2000 nm, preferably between about 400 nm and 1500 nm. In a particular embodiment, the fluid applicator comprises a pump means that is able to eject treatment fluid from the container onto the skin to be treated. A pump means is well suited for reliably applying the treatment fluid, since it is a means that is able to actively eject the treatment fluid, independent of whether or not there is physical contact between the device and the skin. Herein, a pump means comprises all means that are able to eject treatment fluid from its container, through the release opening, such as a conventional pump, an atomizer, a piston, any means for exerting pressure on a collapsable or compressible container, etc. In appropriate cases, the container itself will then be collapsable, compressible etc. It is however alternatively possible to provide a different type of fluid applicator, such as a rotatable element that contacts the treatment fluid in the container and may be brought into contact with the skin to be treated, such as a roller ball or cylinder. The latter type of fluid applicator is especially suited to apply a thin film of treatment fluid. Preferably, the release opening has a width which is substantially equal to a width of the emission window. This allows application of treatment fluid over the full width of the skin area that is treated. Alternatively, or rather, more generally, the fluid applicator is constructed to supply treatment fluid over at least substantially the full width of the emission window, in particular as seen in a direction of movement of the device. This latter embodiment may e.g. relate to an atomizer that applies treatment fluid in a cone the width of which is determined by the distance from the release opening to the skin and by the apex angle. Other ways of delivering treatment fluid to the skin over said width are not excluded. In a particular embodiment, the device according to the invention comprises a plurality of release openings, in particular adjacent the emission window. The presence of more than one release opening offers more flexibility in applying the treatment fluid, especially if they are provided on different sides, in particular opposite sides, and even more preferably around the emission window. For example, use may be made of separate treatment fluids in separate containers, for application of pre-treatment and post-treatment fluids. It is also possible to provide a single container with more than one release opening. This may e.g. be useful in the case of stationary illumination of the skin, to allow release of treatment fluid from all sides of the treated area, or in order to mark and delimit said area. In the case of a device which is moved across the skin during treatment, the presence of more than one release opening ensures that, for more than one direction of movement, the correct application of treatment fluid may be ensured, e.g. before or after illumination. In a particular embodiment, at least one release opening is selectable by a release control unit for releasing treatment fluid. By offering separate control over the release openings, the flexibility of the use of the device is even more improved. E.g., in the case of a device to be moved across the skin, comprising a single container having multiple release openings on different sides, etc., of the emission window, selecting only the one or more release openings on the appropriate side or sides of the emission window enables treatment fluid to be released only through the correct release opening(s), so that no treatment fluid is wasted. Alternatively, or additionally, in the case of a device with more than one container, each having a different treatment fluid, a desired treatment fluid may be selected to be released. Especially, but not exclusively, if the source of the device is furthermore adjustable as to the dose, intensity and or spectrum of the emitted radiation, then a device is provided that can offer more than one kind of treatment, both optically and in terms of the applied treatment fluid. In a special embodiment of the device, the emission window is provided in a recess in the housing and the fluid applicator is constructed to eject treatment fluid into the recess, in particular into the space between the emission window and the part of the skin right below that emission window. This embodiment is suitable e.g. for a point-and-shoot treatment method, in which the device is placed on the skin, a part of the skin is illuminated, after which the device is placed on a next part of the skin to be illuminated. To ensure correct application of treatment fluid, it is desirable to have a space for said fluid, which space is provided in the recess. The treatment fluid may be sprayed into the recess, or pumped such that it will flow into the space etc. Note however that the presence of such a recess is not required, as will be shown further below. Advantageously, the recess extends in at least one direction from the emission window to a perimeter of a surface of the device that is to contact the skin to be treated, such that the recess is in communication with the surrounding environment. In this embodiment, a "tunnel"-like space or groove is provided in the device, at a side that faces the skin to be treated, from the space in front of the emission window to the surrounding environment of the device. This tunnel-like recess need not have a constant diameter, it may e.g. narrow or broaden towards the perimeter, but it is preferred to have a minimum width which is at least as large as the width of the emission window. It is advantageous when the recess extends in a substantially straight line from the emission window to the perimeter. This offers the possibility to apply treatment fluid onto the skin in a layer with a desired thickness, which remains present after illumination, in case the device is moved across the skin in an appropriate direction, such as parallel to the tunnel-like space. This may be useful e.g. in cases where the treatment fluid performs a function not only before or during illumination, but also after illumination, such as cooling and soothing of the skin, but also marking of already treated areas. A further advantage of a recess which is in communication with the surrounding environment, notably the atmosphere, is that the treatment fluid being ejected into the recess or space may readily escape. However, one or more separate venting channels may alternatively, or additionally, be provided. In a special embodiment, the device according to the invention further comprises a control unit, that is constructed to control release of the treatment fluid, in particular when the device contacts the skin to be treated. Providing such a control unit for controlling release of the treatment fluid ensures an even more reliable application of the treatment fluid, since the control unit may allow release, e.g. ejection or pumping, of the treatment fluid only when the device contacts the skin. For example, an applicator that releases treatment fluid may be stopped by the control unit if it is determined that the device no longer contacts skin, to prevent unwanted egress of treatment fluid. For this reason, it is conceiveable that the control unit or the device as a whole comprises a sensor, that is able to sense the presence of skin, or some other surface. Examples are sensors that measure conductivity, or sensors that are sensitive to light or body temperature, all of which are well . known in the art per se. Other sensors may take the form of a movable part that may be pushed e.g. into a recess by applying the device to the skin, such as a knob or a comparable switch button. Alternatively, or additionally, such a movable knob may be positioned such that by applying the device to the skin, the container is compressible by the knob, thus enabling treatment fluid to be expelled from the container. Advantageously, the device comprises a control unit that controls the fluid applicator in dependence on at least one of a motion of the device across the skin to be treated and an emission of optical radiation. To this end, a type of sensor may be provided that measures motion, e.g. speed, in the form of a wheel etc., and/or a sensor or other devices that give a signal relating to the emission of radiation from the source. The latter may be a simple on/off switch, a dosimeter, etc. This may be combined with the control unit that controls in dependence on contact between device and skin, mentioned above, or with e.g. a source control, if desired, e.g. in the form of a microcomputer or similar circuitry. In a preferred embodiment, the container contains a treatment fluid, comprising a component that is able to form a visible residu on the skin. This makes it easier to visually check which areas of the skin have already been treated. This is especially important for cases in which the result of the treatment is not immediately visible or noticeable. In such cases it would be possible to "forget" areas of the skin, e.g. leave unwanted hairs on the skin, while other areas might receive more than one treatment, which may damage the skin, either directly or in the long term, through too high doses of radiation or otherwise. As a matter of fact, the more reliable application of treatment fluid, made possible by means of the present invention as described in this document, offers such an improved visual check. The visibility may be provided by various means. For example, the mere presence of the substance on the skin itself is sufficient in some cases. In other words, it is possible that the residu is the treatment fluid itself. However, it is possible that the treatment fluid is easily absorbed by the skin, or evaporates rapidly, at least with respect to the treatment time necessary to cover the desired total skin area. In such cases, it is difficult to determine with limited effort which skin parts have been treated, and which have not. Therefore, preferably, the residu is visible for at least 5 minutes, more preferably at least 10 minutes, and most preferably for an indefinite duration, which is substantially only influenced by active removal through washing off etc. Visibility of such duration may be obtained in many ways, e.g. using a waxy treatment fluid. In a preferred embodiment, the treatment fluid comprises a coloured material or a reflective material. This clearly marks the treated areas, thereby reducing the risk of errors due to the presence of e.g. sweat or sebaceous matter, especially in the case of conspicuous colours. An other way of providing the treatment fluid with good and durable visibility properties is however also conceiveable. Note that preferably the fluid remains sufficiently transparent to the radiation for illuminating the skin. This may be achieved by selecting an appropriate colorant, e.g. in the case of photodepilation a red or orange colorant or any other material that will attenuate long wave radiation, having a wavelength of, say, 500 nm or longer, to a smaller degree than short wave radiation, having a wavelength shorter than, say, 500 nm. The treatment fluid in the container may be any suitable fluid that supports, or is useful in, the treatment. Often, they are water-based or oil-based. The viscosity may have any value suitable for the treatment fluid to be released from the container by the action of the fluid applicator. Too low a value is less preferable, as control may become difficult, either before or after application onto the skin. The treatment fluid may comprise e.g. a depilation promoting agent, more preferably an optical coupling gel and/or skin care gel. The optical coupling gel may have sufficient transparency to the radiation used, and have a refractive index between those of the (average) skin and the material of the emission window (if such a window is used). Skin care gel may comprise substances that help carry off heat that developed in the skin due to the illumination, or provide care to prevent unwanted damage by the radiation, etc. In a preferred embodiment of the device according to the invention, the container comprises a removable fluid cartridge. In this way it is easy to maintain the device, since an empty cartridge may be exchanged for a filled cartridge, or for a cartridge containing a different treatment fluid. However, it is also possible to use a container that is fillable through a filler opening or the like. The type of optical treatment of the skin is not particularly limited. Preferred treatments are the so-called photoepilation, sometimes called photodepilation, and photorejuvenation of the skin. In particular, the source is constructed to emit optical radiation which is effective to cause photodepilation. To be effective to cause photodepilation, said optical radiation should be emitted in a sufficient dose and/or intensity and/or spectral distribution to cause sufficient damage to reduce hair growth and/or to cause shedding of the ^• hair. Various mechanisms are known, such as providing sufficient radiation that is absorbable by e.g. melanin in a hair, to cut the hair. This mechanism gives a relatively quick, though not necessarily immediate result. Another method is to supply sufficient radiation to irritate and damage the hair follicle, such that the hair is released and/or the hair growth cycle is slowed or stopped, depending on inter alia, intensity and duration of the illumination. This gives a time-delayed result, though in principle also a long-lasting or even permanent result. Other methods are possible, as well as other obtainable effects, such as reducing wrinkles in the skin, which is also a long-term effect. It is particularly with such long-term effects, that cannot be seen immediately after the treatment, and thus with the devices for carrying out the appropriate methods, that the device according to the invention offers important advantages, in that it is more reliable to limit the number of treatments of every part of the skin to exactly 1, instead of missing spots or overilluminating them. For more details about photodepilation and photorejuvenation, reference is made to the following handbooks: Laser Hair removal, D.J. Goldberg, 2000, 1st ed., and Ablative and Non- Ablative Facial Skin Rejuvenation, D.J. Goldberg, 2003, lst ed. Relevant quantities for the two mentioned photodepilation methods relate to the intensity and dose of the radiation, the latter method generally requiring a lower dose and intensity. Devices for carrying out photodepilation methods thus have radiation sources that are correspondingly controllable. In a particular embodiment of the device according to the invention, the source is controllable to emit optical radiation with a dose energy density of between 0.5 and 100 J/cm2 in a wavelength region between 550 and 1500 nm. Such ranges have proved to be useful in photodepilation; lower doses of between 0.5 and about 10 J/cm2 being preferred for more skin- friendly, long-term effects. Appropriate light sources will be discussed in the description of preferred embodiments, further below. In another advantageous embodiment of the device according to the invention, a source control unit with a residu sensor is provided, wherein the source is controllable by the source control unit. Herein, "residu" relates to the residu of the treatment fluid on the skin, being either the treatment fluid itself or only a part thereof. The residu sensor is able to provide a signal in dependence on the presence of said residu. The source control unit may respond to said signal by switching off the source, as the presence of the residu indicates an already performed treatment on that part of the skin. It is thus even better ensured, by automation of the operation, that no part of the skin is illuminated more than once. To enable the sensor to determine the presence of residu, any substance may be provided in the treatment fluid that is detectable on the skin by a sensor, such as various chemicals, or conductive particles etc.

Embodiments of a device for treatment of human skin in accordance with the invention will be described in the following description with reference to the drawings, in which: Fig. 1 diagrammatically shows a first embodiment of a device according to the invention; Fig. 2 diagrammatically shows a partial cross-sectional view of a second embodiment of a device according to the invention; Fig. 3 shows a diagrammatic top view of the second embodiment of Fig. 2; and Fig. 4 diagrammatically shows a third embodiment of a device according to the invention. Fig. 1 diagrammatically shows a first embodiment of a device 1 according to the invention. Herein, a housing is denoted 2, 4 is a source of radiation in a radiation housing 6 having an emission window 8. Reference numeral 10 is a first container with treatment fluid 12, that is ejectable via duct 14 and through a first release opening 16. Duct 14 is selectably closable via a first valve 18. A piston 20 is driven by a motor 22, controllable by control unit 24. A second container 26 holds a cartridge 28 with treatment fluid, which is ejectable via second duct 30 which opens into a second release opening 32, and is selectably closable by a second valve 34. A motion sensor is denoted by 36, and a radiation sensor by 38. The housing may have any shape that is appropriate for the selected treatment and the skin part to be treated, such as a rectangular, oval, round or rounded-off shape. A handleable size is preferred. The emission window 8 as shown here comprises a plate of a material which should be sufficiently transparent or translucent to the radiation to be used. Preferably, other properties are advantageously selected, such as good thermal conductivity and abrasive resistance, low toxicity, etc. An exemplary, though non-limiting, material may be sapphire, although many types of glass and plastics etc. are also conceiveable. Note that the presence of such a plate is optional, and the window could comprise a simple opening in the housing 2. The radiation housing 6 is also optional, but has advantages in guiding radiation through the emission window 8. Examples are paraboloids etc., often made of aluminum, silvered plastics or any other material with sufficient reflectivity. The source 4 of radiation is selected according to the desired radiation properties, and may e.g. comprise a flash lamp, a halogen incandescent lamp, a laser source, LEDs and so on. It may be a cw source or an intermittent or pulsed source. For photodepilation, a source that emits at least in a part of the wavelength region 500-1500 nm has proved useful, although other wavelengths are not excluded, neither for photodepilation, nor for other treatments, such as tanning, photorejuvenation etc. Note that many treatments, such as all of the above, often, if not always, provide results only after a certain time-delay of e.g. an hour, a day or more. For such treatments, a device of the types according to the invention, that provide accurate application of treatment fluid, and also a visual check as to which parts of the skin have been treated, show advantages over known devices. The first container 10 contains a (first) treatment fluid 12, which is not particularly limited, but may contain widely varying products such as skin lotions or moisturizers, depilation supporting products, tanning lotions, and so on. It preferably comprises at least one component that ensures sufficient visibility for a time period that is sufficient to complete the treatment. Such component may be the treatment fluid itself, e.g. if this has a colour of its own, and is not readily absorbed by the skin, or evaporates sufficiently slowly, such as less than 50% in, say, 10 minutes, depending on the speed of the treatment. It is also possible to provide an additive, such as a colorant, or any other visible material. The treatment fluid 12 may be kept in a state ready to be expelled from the container 10 by a piston 20, which is actuatable by a motor 22, which is controllable by a control unit 24. The piston may thus exert pressure on the treatment fluid 12, and drive it through (first) duct 14 towards a first release opening 16. Any other type of pump means, such as a membrane pump etc. is also conceiveable. The release opening 16 is located at a distance d from the emission window 8. In order for the device to be able to reliably prepare skin to be treated, as well as mark skin that is (to be) treated, this distance should not exceed a predetermined value, which somewhat depends on the type of treatment applied. For example, if the treatment acts very locally, such as tanning or depilation, a small distance d should be selected, for example less than 1 cm, and preferably 0 cm. The first duct 14, and thus release of the treatment fluid 12 from the first container 10, is controllable by means of a valve 18, which could alternatively be any other device that may prevent unwanted release of treatment fluid. The valve 18 is controllable by control unit 24, which may comprise electronic circuitry, a microcomputer, a link to an external computer, etc. The valve 18 may also be used to control the amount of released first treatment fluid, in order to be able to apply a layer with a predetermined and preferably controllable thickness. Alternatively, or additionally, this layer thickness may be influenced or controlled by means of the pressure exerted by the piston 20, or any comparable means, such as gas pressure in the container 10 etc. It is noted here that the first container 10 may be connected to more than one release opening 16, e.g. openings regularly distributed around the emission window 8. Alternatively, the release opening may itself extend partly or completely around the emission window 8. A second container 26 comprises a cartridge 28 with second treatment fluid.

The cartridge may be of any known type, such as collapsable or compressible cartridges. Rigid cartridges are however also possible. By any known means (not shown here) the contents of the cartridge, i.e. a second treatment fluid, which is similar to or different from the first treatment fluid 12, is ejectable through duct 30 which opens into a second release opening 32 and is selectably closable by a second valve 34, which is controllable by control unit 24. An optional motion sensor is shown by 36, while an optional radiation sensor is denoted by 38. The motion sensor 36 may comprise any means for providing a signal that depends on e.g. speed of the device when moving across the skin, or on the distance travelled. The motion sensor may thus comprise e.g. a speedometer or a hodometer, which may be based on a rotatable wheel that contacts the skin etc. A signal derivable from the motion sensor 36 may be processed by control unit 24, or, directly, by any separate control means, by valve 34 etc., in order to decide whether or not to open or close second duct 30 via second valve 34. This may depend on whether the second treatment fluid should be released before or after illumination by the source 4. Furthermore, the rate of release of second treatment fluid may depend on the speed of the device, etc. This allows reliable control of the layer thickness of the released treatment fluid. The radiation sensor 38 may measure the intensity and/or dose of the emitted radiation. The signal from sensor 38 may be used to give feedback to the control unit 24, or a separate source control unit (not shown here), to control the source 4 of radiation, but possibly also to control the amount of released treatment fluid 12. For example, depending on a set intensity or dose of radiation, the quantity of treatment fluid 12 may be adapted. This may be performed automatically, be a set program or the like. This enables the user to always apply the correct amount of treatment fluid. Fig. 2 diagrammatically shows a partially cross-sectional view of a second embodiment of the device according to the invention. This device is generally denoted 1'. Note that throughout the drawings, similar parts are denoted by the same reference numerals and are only repeated and discussed where useful for the further understanding of the invention. The housing 2 holds the emission window 8 in a recess 40, which extends via tunnel-like region 42 to the surrounding environment. The first container 10 is connected to the recess 40 via a first release opening 16'. First treatment fluid may be ejected into recess 40 as a spray, a layer between skin and emission window 8 and so on. For this purpose, the recess 40 may have dimensions that substantially correspond to those of the emission window 8. Optionally, and as shown in the Fig. 2, the recess 40 may be connected to, or may continue as, a tunnel- like region 42 towards a perimeter of the housing 2. This offers the advantage that applied treatment fluid is no longer influenced by a moving housing, e.g. by scraping treatment fluid off the skin, which might otherwise collect in the recess. Any treated part may thus be marked very reliably. It also offers the advantage that any air trapped under the emission window, i.e. in the recess 40, may readily escape to the surrounding environment. Fig. 3 shows a diagrammatic top view of the second embodiment of Fig. 2. Herein, the device 1' is placed onto a skin 50, and has left a residu 52. Release opening 16' has about the same width as emission window 8 and recess 40 (not shown) and tunnel-like region 42. This allows treatment fluid to be released over the entire skin area being treated . As can be seen, the shape of the emission window 8, and of the recess, which is not shown separately, but coincides with the emission window in this view, and of the tunnel- like region 42 are such that released treatment fluid is substantially not influenced by moving the device across the skin 50. The treatment fluid is able to leave a residu 52 on the skin, clearly indicating the treated skin area. The user is now able to locate the device 1' on a skin part that has not been treated. Fig. 4 diagrammatically shows a third embodiment of the device according to the invention. The first container 10 is in connection with a rotatable ball 54 via a gap 56, and is fillable via filler opening 58. A third container 60 opens into radiation housing 6 via a third release opening 62, that is capable of ejecting a spray 64. A residu sensor is denoted by 66. Second container 70 is operable by push button 72, and opens into second release opening 74. In this device, the window is simply a hole in the housing 2, without a cover plate. The first container 10 is fillable through filler opening 58. Note that in many

(other) cases it is also possible to fill the container via its associated release opening. The container 10 is closed on one side by a rotatable ball 54. When the ball 54 rotates, e.g. due to movement of the device in contact with and across the skin to be treated, the ball 54 will transport treatment fluid from the container 10 to the skin, thereby forming a layer of controlled thickness. Such mechanism is widely known, e.g. for ballpoints, certain types of deodorant etc. A second container 70 is operable by a push button 72. This push button may be operated by the user. E.g., the second container 70 may emit treatment fluid for as long as the push button is pushed by the user. Preferably, in that case the source is coupled to the push button, such that the source will be "off when the push button is not being pushed.

Even more preferably, the push button is constructed and/or located such that in an operative position of the device on a skin to be treated, the push button 72 is automatically actuatable to operate the second container 70. Note that the associated release opening 74 is located adjacent or very close to the emission window. This allows precise indication of the treated skin area. A third container 60 is provided, which opens into its associated release opening 62, which is designed such that it will emit a spray 64. This spray 64 is able to cover the skin area under the emission window of the device, i.e. under the radiation housing 6. This is rather effective in a point-and-illuminate device, where the device is placed on the skin, and illumination is effected by providing one or more radiation pulses or flashes. A residu sensor 66 is provided, which may be connected to control unit 24. The contact sensor should be interpreted to include sensors that determine the presence of contact with the skin to be treated, or a surface in general, but also the presence of treatment fluid, or a residu thereof. This offers the possibility that, when the residu sensor 66 determines the presence of such fluid or residu, the source 4 and/or one or more fluid applicators or release openings may be switched off, either completely, or partly. This latter measure may be achieved e.g. by providing a number of sensors, that cover a certain width. Any contact sensor that senses treatment fluid or residu may then switch off corresponding source(s) or adapt illumination, and/or close an appropriate part of the release opening(s). In this way, very efficient treatment is possible without the risk of more than one treatment for skin parts, which may cause damage through an overdose of radiation. Note that in the above a number of alternative or supplementary containers and fluid applicators are given. They need not all be present in the same device. Nor is their number in such a device limited to 1. Instead, two or more such fluid applicators and/or containers in one device give more flexibility. The above description, both of the general invention and of preferred embodiments, is not intended to be limiting, but rather to provide a better understanding of the invention, the scope being determined by the appended claims. Important aspects of the invention are the provision of a reliable and controllable application of treatment fluid on a skin, as well as the reliable marking of treated areas during treatment. Especially in the case of treatments that show results after lapse of some time, this reliable application and marking is important.

Claims

CLAIMS :

1. A device (1) for treatment of human skin using optical radiation, comprising: a housing (2) with a source (4) of optical radiation and an emission window

(8) defining a treatment area on a skin to be treated; a container (10, 26; 60, 70) for a treatment fluid (12); and a release opening (16, 32; 16'; 62, 74) adjacent to or opening into the emission window (8) for releasing treatment fluid onto the skin; characterized in that the device further comprises a fluid applicator (20, 22; 54,

72) that is constructed to release a predetermined amount of the treatment fluid (12) from the container (10, 26; 60, 70) onto the skin.

2. A device according to claim 1, characterized in that the fluid applicator comprises a pump means (20, 22) that is able to eject treatment fluid (12) from the container (10) onto the skin to be treated.

3. A device according to claim 1, characterized in that the release opening (16,

32; 16'; 62, 74) has a width which is substantially equal to a width of the emission window (8).

4. A device according to claim 1, characterized in that the device comprises a plurality of release openings (16, 32) adjacent the emission window (8).

5. A device according to claim 4, characterized in that at least one release opening (16, 32; 16', 62, 74) is selectable by a release control unit (24) for releasing treatment fluid (12).

6. A device according to claim 1, characterized in that the emission window (8) is provided in a recess (40) in the housing (2) and the fluid applicator is constructed to eject treatment fluid into the recess (40).

7. A device according to claim 6, characterized in that the recess (40, 42) extends in at least one direction from the emission window (8) to a perimeter of a surface of the device (1') that is to contact the skin to be treated, such that the recess (40, 42) is in communication with the surrounding environment.

8. A device according to claim 1, characterized in that the device further comprises a confrol unit (24) that is constructed to control release of the freatment fluid (12) when the device contacts the skin to be freated.

9. A device according to claim 8, characterized in that the control unit (24) controls the fluid applicator (20, 22; 54, 72) in dependence on at least one of a motion of the device across the skin to be treated and an emission of optical radiation.

10. A device according to claim 1, characterized in that the container (10, 26; 60, 70) contains a freatment fluid (12) comprising a component that is able to form a visible residu (52) on the skin.

11. A device according to claim 1, characterized in that the treatment fluid (12) comprises a coloured material or a reflective material.

12. A device according to claim 1, characterized in that the container (26) comprises a removable fluid cartridge (28).

13. A device according to claim 1, characterized in that the source (4) is constructed to emit optical radiation which is effective to cause photodepilation.

14. A device according to claim 1, characterized in that a source control unit (24) with a residu sensor is provided, wherein the source (4) is controllable by the source control unit (24).