WO2010079463A1

WO2010079463A1 - A device for treating human keratinous materials

Info

Publication number: WO2010079463A1
Application number: PCT/IB2010/050101
Authority: WO
Inventors: Roxane Gavillon; Jean-Thierry Simonnet
Original assignee: L'oreal
Priority date: 2009-01-12
Filing date: 2010-01-12
Publication date: 2010-07-15
Also published as: FR2940915A1; FR2940915B1

Abstract

A device (1) for treating human keratinous materials, in particular the skin or the hair, the device comprising: • a support (2) bearing a photocatalytic material and configured to come into contact with the keratinous materials; • a first light source (10) configured to illuminate the photocatalytic material so as to subject impurities present in contact with said material to a photocatalytic reaction; and • a second light source (20) different from the first, and configured to emit light essentially in a range of ±100 nm around at least one dominant wavelength, and having a cosmetic or therapeutic action on the treated keratinous materials.

Description

A DEVICE FOR TREATING HUMAN KERATINOUS MATERIALS

The present invention relates to treating human keratinous materials, in particular the skin and the hair .

Background

Keratinous materials tend to lose some of their qualities under the action of factors such as natural greasing, sebum, sweat, eliminating skin flakes, pollution, using detergents, aging, bacteria, and humidity, amongst others.

The look or the feel of the skin or the hair can thus become degraded. In order to provide a remedy it is possible to remove dirt, to combat stresses, and to seek to improve the state of keratinous materials.

The skin is usually cleaned with the help of cleansing compositions, frequently including surfactants, particles having an abrasive effect (for scrubbing) , and amphiphilic polymers. Nevertheless, situations may exist in which a person desires to clean the skin or the hair without using water or a cleansing composition. Furthermore, frequent use of surfactants can irritate more sensitive skins.

An object of the invention is to prepare the skin for cleansing by a non-detergent method in order to limit significantly the quantity of washing agent that is used subsequently, for the purpose of reducing irritation, in particular for sensitive skins.

Patent application KR 2004/0101585 describes an appliance for cleansing and disinfecting the skin by photocatalysis activated by a source of ultraviolet (UV) or visible light. Such an appliance makes it possible to avoid using a cleansing composition. The action of the appliance is nevertheless limited to cleansing.

Summary

There exists a need to further improve appliances for cleansing the skin or the hair, in particular for treating keratinous materials in addition to or simultaneously with cleansing them.

There also exists a need to combat the discomforts to which keratinous materials are subject.

The invention seeks to satisfy these needs in full or in part, and it provides a device for treating human keratinous materials, in particular the skin or the hair, the device comprising: • a support bearing a photocatalytic material and configured to come into contact with the keratinous materials;

^• a first light source configured to illuminate the photocatalytic material so as to subject impurities present in contact with said material to a photocatalytic reaction; and

^• a second light source different from the first, and configured to emit light essentially in a range of ±100 nanometers (nm) around at least one dominant wavelength, in order to exert a cosmetic or therapeutic action on the treated keratinous materials. The term "essentially" should be understood as meaning that light emitted outside the range is negligible or even not measurable . Surprisingly, it has been found that cleansing keratinous materials by photocatalysis, prior to or simultaneously with exposure of the keratinous materials to the second light source (the source that serves to apply cosmetic or therapeutic treatment to said materials) can be beneficial to the effectiveness of the light emitted by the second light source that is used for treatment, compared with its effectiveness when it is applied on its own or in association with conventional cleansing of the keratinous materials. The invention may be applied to cleansing and treating various regions of the face or the body, such as the forehead, the cheeks, the chin, the hands, the armpits, the groin, the feet, the scalp, or the hair.

The device may be suitable for being carried in one hand only. It may be wireless and rechargeable, where appropriate.

The invention enables a single device to be used both for cleansing keratinous materials and for applying cosmetic or therapeutic treatment thereto by phototherapy. The term "cosmetic treatment" is used to mean improving the state and/or the appearance of keratinous materials, by means of a preventative or curative action that is not therapeutic.

The cosmetic treatment of the invention is not depilatory and is not depigmenting, and it is not intended for painful skin or pathological situations.

The treatment may stimulate or inhibit a property of the keratinous materials, as explained in detail below.

By way of example, the device may be used for eliminating impurities over a duration lying in the range 10 minutes or less to one minute or less, during which time the photocatalytic material is in contact with the keratinous materials and is subjected to illumination by the first source. When the device is used for treating keratinous materials by exposing them to the radiation emitted by the second source, the device may optionally be in contact with the keratinous materials.

The support may comprise a substrate that is transparent or translucent to the radiation emitted by the first and second sources. The second light source may be substantially monochromatic, with a spectrum width that is less than or equal to 50 nm, better less than or equal to 15 nm, or even 10 nm.

The first light source may comprise one or more light-emitting diodes (LEDs) . The second light source may comprise one or more LEDs or laser diodes. The second light source may emit continuously.

The device may be configured to enable the user to control the operation of the light sources independently of each other.

The power of the incident light on the photocatalytic material may lie in the range 0.01 milliwatts per square centimeter (mW/cm²) to 500 mW/cm², and preferably in the range 1 mW/cm² to 100 mW/cm².

The light emitted by the second source may pass through the support prior to reaching the keratinous materials . The dominant wavelength of the second source may be selected so as to present: action on the production of sebum; action against acne; action against rosacea; action of rejuvenating the skin; action of improving the elasticity of the skin; action on the production of collagen; action on hair growth; action on wrinkles; action on stretch marks; action on cellulite; action on psoriasis; action on burns or wounds; action on reducing scars; action against inflammation of the skin; and/or action on perspiration; amongst others. The dominant wavelength (s) of the second light source may be selected from any one of the following ranges: 390-450 nm; 400-470 nm; 530-600 nm; 600-700 nm; 620-680 nm; 760-880 nm; and 800-1000 nm.

The invention also provides a cosmetic treatment method, e.g. by implementing a device as defined above, the method comprising the steps consisting in: a) bringing a photocatalytic material into contact with the keratinous materials and degrading impurities in contact with the photocatalytic material by a photocatalytic effect by exposure to the light emitted by the first light source; and b) exposing the keratinous materials to the radiation emitted by a second light source that is different from the first and that is configured to emit light essentially in a range of ±100 nm about at least one dominant wavelength, and present cosmetic or therapeutic action on the treated keratinous materials, e.g. in order to obtain a cosmetic effect.

Step b) may take place simultaneously with step a) , or in a variant step b) may take place after step a) . The method may also include the following step: c) cleansing the exposed skin using a gentle skin cleanser .

Eliminating impurities may enhance the action of the light radiation used for exerting the cosmetic or therapeutic action, e.g. by reducing the shine or sheen associated with the presence of sebum, thus enabling reflection losses of the radiation used for the phototherapy to be reduced.

The dominant wavelength (s) of second light source may be selected from:

^• the range 530-600 nm and/or 760-880 nm, or the range 620-680 nm, for skin rejuvenating action and/or for action on collagen;

^• the range 760-880 nm for action stimulating hair growth;

^• either of the ranges 630-660 nm and 790-904 nm for action combating hair loss;

^• either of the ranges 620-680 nm and 760-880 nm for treating wrinkles; • the range 760-880 nm for action against stretch marks ;

^• the range 760-880 nm for action treating cellulite;

^• the range 600-700 nm for action treating psoriasis;

^• the range 760-880 nm for action treating burns;

^• the range 380-1250 nm for action treating wounds; ^• any one of the ranges 380-420 nm, 620-680 nm, and 760-830 nm for action reducing scars;

^• either of the ranges 630-680 nm and 800-1000 nm for action treating inflammation of the skin; • the range 530-600 nm for action treating rosacea or other red patches of the skin; and

^• the range 300-1300 nm for preventative action against acne.

The presence of two light sources within the same device may also enable common components to be used for both sources, e.g. a common power supply and/or a shared electronic circuit, e.g. for controlling light intensity and one and/or the other of the sources and/or the duration of illumination. Where appropriate, optical components may also be common to both light sources, e.g. for diffusing or focusing light on the keratinous materials.

The two light sources may be distinct. In a variant, the two light sources may be formed from a common illuminant used in association with a frequency multiplier for one of the sources.

The support may comprise a substrate, also referred to as a window, that is transparent or translucent and that may be covered on its outside face by the photocatalytic material, which material may for example be in the form of a coating comprising photocatalytic particles. The substrate must be sufficiently transparent at the wavelength used for photocatalysis and also at the wavelength used for the cosmetic or dermatologic treatment when the light used for said treatment passes through the substrate prior to reaching the keratinous materials. A different configuration may be provided, with the light that is used for cosmetic or therapeutic treatment then reaching the keratinous materials without passing through the substrate.

Nevertheless, it is advantageous for the radiation from the second source also to pass through the substrate, since that may enable the device to be made to be relatively compact.

The photocatalytic material is sensitive to the action of the light radiation used for photocatalysis . Photocatalysis may rely on exciting a photocatalyst with light radiation presenting energy that is not less than that of its forbidden band. These catalytic materials used may be semiconductors having a wide forbidden band, e.g. oxides or sulfides such as TiO₂, ZnO, ZnO₂, CeO₂, Cu₂O, SiO, SiO₂, MoS₂, InPb, RuO₂, ZrO₂, SnO₂, CdS, ZnS, SrTiO₃, GaP, InP, GaAs, BaTiO₃, KNbO₃, Fe₂O₃, Ta₂O₅, WO₃, NiO, and compounds thereof, this list not being limiting.

The photocatalytic material may comprise titanium oxide, which is advantageous because of its chemical stability and its low cost.

Under the effect of light, the photocatalytic material degrades organic dirt present at the surface of the material. The speed of the photocatalytic reaction depends on the intensity of the flux of incident photons. Photon intensity is governed mainly by the power of the light radiation and by the distance between the light emission source and the photocatalyst.

By way of example, when a photocatalyst such as TiO₂ is subjected to radiation by photons presenting energy that is not less than its energy gap of 3.2 electron volts (eV) , an electron may go from the valance band to a vacant orbital of the conduction band. That creates an oxidation site or a positive hole in the valence band and a reduction site with the release of an electron in the conduction band. Redox reactions are then possible. The absorbed impurities are degraded by the radical ions formed at the surface of the TiO₂, leading to CO₂ and H₂O mineralization .

As examples of photocatalytic titanium dioxides, mention may be made of those sold by the supplier Kronos under the references vlp 7000, which is active in visible light, and uvlp 7500, which is active in ultraviolet radiation .

The photocatalytic material may be deposited on the substrate in a continuous form so as to occupy the entire area of the outside surface of the substrate. In a variant, the photocatalytic material may be deposited on the substrate without occupying the entire area of the outside surface of the substrate, e.g. by being deposited in the form of islands or of a silk screen. The coating of photocatalytic material may be obtained by various deposition methods, e.g. a chemical vapor deposition (CVD) method, a cathode sputtering method, or a sol-gel type method. The photocatalytic material may be in particulate form. The substrate bearing the photocatalytic material may be made of glass, quartz, polycarbonate, polymethyl methacrylate, polypropylene, polyurethane, polyvinylbutyral, poly (ethylene terephthalate) , poly (butylene terephthalate), an ionomer resin such as an ethylene and acrylic acid copolymer or an ethylene and methacrylic acid copolymer neutralized by a polyamine, a cyclo-olefin copolymer such as ethylene/norbornene copolymer or ethylene/cylopentadiene copolymer, polycarbonate/polyester copolymer, ethylene/vinyl acetate copolymer or the like, alone or in mixtures.

The first light source may emit UV radiation. Under such circumstances, preference should be given to making the substrate out of materials that are sufficiently transparent to light in the range 208 nm to 400 nm. The support may have various shapes, for example it may be circular, square, or rectangular, with an outside face that is plane or outwardly convex, and it may have a section taken perpendicularly to the path of the light that occupies an area lying in the range 0.5 square centimeters (cm²) to 50 cm², for example.

On its face that is to come into contact with keratinous materials, the support and in particular the substrate may include means that enable impurities to be absorbed, e.g. particles that absorb oils and more specifically sebum, it being possible for said particles to be secured to the support in various ways, e.g. by being grafted or adhesively bonded thereto.

The support may comprise fibers, more particularly mineral fibers . The mineral fibers may be covered in photocatalytic particles. The fibers may absorb the above-mentioned impurities. By way of example, mention may be made of Quartzel PCO fibers from the supplier

Saint Gobain, which are silica fibers covered in a layer based on titanium oxide. These fibers are described in international application WO 2003/010106.

The support may also be constituted by a block of interlaced fibers forming a porous block, that is capable of absorbing the above-mentioned impurities, and that is removable, repositionable, and suitable for cleaning in water .

Where appropriate, the support may receive surface treatment for conferring a certain amount of roughness thereto, where such roughness may improve capture of impurities by the device.

The first light source and the second light source may be selected from incandescent, halogen, UV, fluorescent, and flash lamps, lasers, and light-emitting diodes (LEDs, organic LEDs (OLEDs), ...) . It is preferable to use LEDs.

The light emitted by the first light source or by the second light source may be pulsed or it may be non- pulsed. The light emitted by the first light source may be non-pulsed. The light emitted by the second light source may be pulsed or non-pulsed depending on the application .

The power of the first light source may lie in the range 0.01 mW/cm² to 500 mW/cm² and preferably lies in the range 1 mW/cm² to 100 mW/cm². The power of the second light source depends on the treatment undertaken. The illumination need not be distributed uniformly over the treated surface and it need not be continuous in time. As a result, certain zones may receive, either locally or at certain moments, powers that are higher, while other zones may receive powers that are lower or even zero.

The light may be concentrated on a few zones within the region being treated.

An optical system may be used for focusing or defocusing the light, e.g. a system comprising at least one lens or microlenses.

The second light source may be substantially monochromatic, presenting a spectrum width that is less than or equal to 50 nm, or even 10 nm, or 2 nm, or 1 nm. The spectrum width is the difference between the wavelengths situated on either side of the dominant wavelength and for which intensity is equal to Imax/10. Imax designates the maximum light intensity at the dominant wavelength. The device according to exemplary embodiments of the invention may implement a plurality of light beams that are parallel, converging, or diverging.

A plurality of beams may be caused to converge on a common point in order to perform the cosmetic or therapeutic treatment. This may enable zones to be treated that are situated beneath the surface of the skin, in particular when the second source emits in the infrared.

In order to adjust the spectral characteristics of the light received by the keratinous materials, use may be made of one or more filters, optical gratings, or prisms .

The treatment may comprise exposing the keratinous materials to radiation at a plurality of different dominant wavelengths, presenting effects that combine, e.g. radiation in the visible and radiation in the infrared. Under such circumstances, the device may include additional light sources, other than the first and second sources.

The use of LEDs makes it easy to provide a plurality of substantially monochromatic sources that emit at different dominant wavelengths. Some LEDs may also be used that emit at at least two dominant wavelengths, e.g. one in the visible and another in the infrared. Multicolor LEDs may be used.

The treatment may also include emitting radiation at different dominant wavelengths in succession, with radiation at one of the wavelengths enhancing the action of the radiation at the other wavelength, for example.

The region for treatment may extend over several tens of square centimeters, and the light beam from the second source may be swept over this zone.

The sweeping may be done by hand. In particular, the device used may emit light as a beam and the zone may be swept by moving the appliance more or less perpendicularly to said beam. It is possible to cover the surface for treatment continuously, i.e. it is possible for all of the points of the skin or other keratinous materials for treatment to be subjected to the illumination at least once, or else it is possible to cover part of the surface, i.e. to ensure that certain points but not others are subjected at least once to illumination.

The treatment method may include applying a composition before or after the treatment by exposure to the radiation emitted by the second source.

Stimulating hair growth

The dominant wavelength of the second light source may be selected to lie in the range 620-680 nm or 760- 880 nm to provide action that stimulates hair growth, e.g. using power lying in the range 1 mW/cm² to 250 mW/cm², and better in the range 10 mW/cm² to 100 mW/cm², as described in application CA 2 500 961. The treatment may comprise applying energy lying in the range 1 joule per square centimeters (J/cm²) to 100 J/cm².

Combating hair loss

The dominant wavelength of the second light source may be selected to lie in the range 630-660 nm or 790- 904 nm in order to combat hair loss, as described in application US 2006/0247742. A He-Ne or Ga-As laser may be used. LEDs having a dominant wavelength in the range 630-660 nm and luminous intensity lying in the range 2000 millicandelas (mcd) to 4000 mcd may be used.

Rejuvenating the skin/action on collagen The dominant wavelength of the second light source may be selected to lie in either of the ranges 530-600 nm and 760-880 nm.

Application US 2005/0283211 describes the use of a wavelength of 590 nm emitted by LEDs.

Treating wrinkles

The dominant wavelength of the second light source may be selected to lie in one of the ranges 620-680 nm and 760-880 nm at a power that is adapted to treating wrinkles, as described in application CA 2 500 961, or in one of the ranges 400-470 nm, 530-600 nm, and 630-680 nm, as described in application WO 2008/057640.

Treating stretch marks The dominant wavelength of the second light source may be selected to lie in the range 760-880 nm at power adapted to treating stretch marks (striae) , as described in application CA 2 500 961.

Treating cellulite

The dominant wavelength of the second light source may be selected to lie in the range 760-880 nm at a power adapted to treating cellulite, as described in application CA 2 500 961.

Treating psoriasis The dominant wavelength of the second light source may be selected to lie in the range 600-700 nm at a power adapted to treating psoriasis, as described in application CA 2 500 961.

Treating burns

The dominant wavelength of the second light source may be selected to lie in the range 760-880 nm at a power adapted to treating burns, as described in application CA 2 500 961.

Treating wounds

The second light source may present a dominant wavelength selected to lie in the range 380-1250 nm at a power adapted to treating wounds, as described in application CA 2 500 961.

Reducing scars

The second light source may present a dominant wavelength selected to lie in any one of the ranges 380- 420 nm, 620-680 nm, and 760-830 nm at a power adapted to reducing scars, as described in application CA 2 500 961.

Treating inflammation of the skin

The second light source may present a dominant wavelength selected to lie in either of the ranges 630- 680 nm and 800-1000 nm, for action to treat inflammation of the skin, as described in application WO 2008/057640.

Treating rosacea The second light source may present a dominant wavelength selected to lie in the range 530-600 nm, for action for treating rosacea or other red patches of the skin, as described in application WO 2008/057640.

Treating acne The radiation of the second light source may be continuous, with a dominant wavelength possibly lying in the range 410 nm to 420 nm, e.g. being centered around 415 nm, as described in US patent No. 6 887 260.

A device including both an LED emitting pulsed light at a dominant wavelength of 590 nm and a continuous lamp radiating at a dominant wavelength of 415 nm may be used, as described in US patent No. 6 887 260.

The light emitted by the second light source may be pulsed. The pulses may have a pulse width of 800 milliseconds (ms) and they may be at a frequency of 1 hertz (Hz) . The dominant wavelength may be about 400 nm and the power may be 2500 mW/cm² as described in applications WO 2007/092349 and US 2006/0200213.

Application CA 2 500 961 describes using a dominant wavelength selected to lie in the range 390-450 nm or 600-700 nm for treating acne.

Preventative action for acne

The dominant wavelength of the second light source may be selected to lie in the range 300-1300 nm, at emitted power of less than 4 J/cm² for preventative action against acne, as described in application

US 2007/0191822.

The light emitted by the second light source may be continuous and may have a dominant wavelength selected to lie in any one of the ranges 400-490 nm, 560-600 nm, 600-

650 nm, and 790-850 nm, as described in application

US 2007/0191822.

The light emitted by the second light source may be pulsed and may be a dominant wavelength selected to lie in the range 400-490 nm, 560-600 nm, 600-650 nm, or 790-

850 nm. A dermatological composition may be applied in addition to the light treatment.

The above list is illustrative and non-limiting. The person skilled in the art may also refer to application WO 2003/001984, which describes the use of light radiation for treating living cells, e.g. for the purpose of treating warts, or for regulating perspiration .

Brief description of the drawings

The invention can be better understood on reading the following detailed description of non-limiting embodiments thereof, and on examining the accompanying drawings, in which: • Figure 1 is an exploded perspective view showing an embodiment of a device in accordance with the invention;

• Figure 2 is a fragmentary section view of the

Figure 1 device; and • Figures 3 and 4 show another embodiment of a device in accorance with the invention.

More detailed description

The treatment device 1 shown in Figure 1 comprises a housing 4 that houses a first light source 10 and a second light source 20, together with an electrical power supply and a circuit for controlling the sources. A support 2, constituted by a transparent or translucent substrate in the example shown, is removably fastened to the housing 4 and has an outside face that is designed to come into contact with the skin, which face is covered in a layer or in particles of a photocatalytic material 3. In a variant, the support 2 is fastened in non-removable manner to the housing 4. The first and second sources may comprise LEDs, distributed in such a manner as to illuminate the support 2 more or less uniformly. In the example under consideration, the support is in the shape of a disk, but it could have some other shape.

By way of example, the first source comprises LEDs that emit in the UV and the second source comprises LEDs that emit in the visible and/or the infrared, as a function of the treatment to be performed. All of the LEDs that emit at the same wavelength are considered as making up a single source.

The housing 4 includes switches (not shown) enabling the various sources to be switched on or off.

The device 1 is used by switching on the first source 10 and bringing the photocatalytic material into contact with the skin or the hair. The device 1 may optionally be moved in contact with the keratinous material being treated. During this stage of use, impurities that are present in contact with the photocatalytic material are degraded photocatalytically .

The device 1 may also be used to perform phototherapeutic treatment by switching on the second source. The radiation passes through the support 2 and reaches the keratinous materials. Depending on the characteristics on the delivered radiation, various cosmetic actions may be exercised, as described in detail above . When it is desired to treat the hair, the device 1 may comprise two mutually movable portions Ia and Ib, e.g. portions that are hinged together, that are configured to close at least in part on hair as shown in Figure 3. Each of the faces of the device 1 that face the hair may include a photocatalytic material, and each of the two movable portions Ia and Ib of the device may include first and second sources serving respectively to emit radiation for activating photocatalysis and radiation for performing phototherapy. When the second radiation is to be emitted towards the scalp, e.g. in order to stimulate regrowth of hair, the device may be open as shown in Figure 4 so that the radiation having a cosmetic purpose can reach the scalp.

After the device has been used, the organic degradation products may be removed from the support, e.g. with a tissue or a wipe, or by washing if the device is waterproof.

The degradation products present on the keratinous materials may be removed with a conventional cleansing material, e.g. a lotion for the skin or a shampoo for the hair.

The device may be used together with application of a pharmaceutic or cosmetic composition on the zone for treatment. The composition may be applied before, after, or during utilization of the device i the invention. The invention is not limited to the examples described. In particular, the cosmetic or therapeutic treatment may be performed with more than two sources emitting at different wavelengths.

The term "comprising a" should be understood as being synonymous with "comprising at least one".

Claims

1. A device (1) for treating human keratinous materials, in particular the skin or the hair, the device comprising: • a support (2) bearing a photocatalytic material and configured to come into contact with the keratinous materials;

^• a first light source (10) configured to illuminate the photocatalytic material so as to subject impurities present in contact with said material to a photocatalytic reaction; and

^• a second light source (20) different from the first, and configured to emit light essentially in a range of ±100 nm around at least one dominant wavelength, and having a cosmetic or therapeutic action on the treated keratinous materials.

2. A device according to the preceding claim, wherein the support (2) comprises a substrate that is transparent or translucent to the radiation emitted by the first and second sources.

3. A device according to either preceding claim, wherein the second light source is substantially monochromatic, having a spectrum width that is less than or equal to 50 nm, better less than or equal to 15 nm.

4. A device according to any preceding claim, wherein the first light source (10) comprises one or more LEDs.

5. A device according to any preceding claim, wherein the second light source comprises one or more LEDs or laser diodes.

6. A device according to any preceding claim, configured to enable the user to control the operation of the light sources independently from each other.

7. A device according to the preceding claim, wherein the power of the first light source lies in the range 0.01 mW/cm² to 500 mW/cm², preferably in the range 1 mW/cm² to 100 mW/cm².

8. A device according to any one of claims 1 to 7, wherein the light emitted by the second source passes through the support prior to reaching the keratinous material .

9. A device according to any preceding claim, configured in such a manner that the cosmetic or therapeutic action on the keratinous materials treated by the second source is selected from: action on the production of sebum; action against acne; action against rosacea; action of rejuvenating the skin; action of improving the elasticity of the skin; action on the production of collagen; action on hair growth; action on wrinkles; action on stretch marks; action on cellulite; action on psoriasis; action on burns or wounds; action on reducing scars; action against inflammation of the skin; and action on perspiration.

10. A device according to any preceding claim, the dominant wavelength (s) of the second light source being selected from any one of the following ranges: 390-450 nm; 400-470 nm; 530-600 nm; 600-700 nm; 620- 680 nm; 760-880 nm; and 800-1000 nm.

11. A device according to any preceding claim, the second source emitting continuously.

12. A method of cosmetically treating human keratinous materials, the method comprising the steps consisting in : a) bringing a photocatalytic material into contact with the keratinous materials and exposing it to light emitted by a first light source; and b) exposing said keratinous materials to radiation emitted by a second light source (20) different from the first and configured to emit light essentially in a range of ±100 nm about at least one dominant wavelength, and having a cosmetic action on the treated keratinous materials.

13. A method according to the preceding claim, characterized in that it is implemented by means of at least one device according to any one of claims 1 to 11.

14. A method according to the preceding claim, the dominant wavelength (s) of the second light source being selected from:

^• the range 530-600 nm and/or 760-880 nm, or the range 620-680 nm, for skin rejuvenating action and/or for action on collagen; • the range 760-880 nm for an action of stimulating hair growth;

^• either of the ranges 620-680 nm and 760-880 nm for treating wrinkles;

^• the range 760-880 nm for action against stretch marks;

^• the range 760-880 nm for action against cellulite; and • the range 300-1300 nm for preventative action against acne.

15. A method according to claim 12 or claim 13, step b) taking place simultaneously with step a) .

16. A method according to claim 12 or claim 13, step b) taking place after step a) .