WO2024223614A1

WO2024223614A1 - Kit for keratinic fibers strand and related treatment process

Info

Publication number: WO2024223614A1
Application number: PCT/EP2024/061174
Authority: WO
Inventors: Gabin Vic; Jonathan Thery; Sophie FRECHIN; Floriane SLEZARSKI; Valentin LUX; Fabrice OSOLIN
Original assignee: LOreal SA
Current assignee: LOreal SA
Priority date: 2023-04-24
Filing date: 2024-04-24
Publication date: 2024-10-31
Anticipated expiration: 2025-10-24
Also published as: FR3147938B1; FR3147938A1

Abstract

The invention relates to a kit (10) for strand (12) of keratin fibers comprising an illumination device (14) comprising: - a first arm (30) and a second arm (32) that are movable between a position for inserting the strand (12) and a containment position wherein the arms define a cavity (34) for illuminating the strand (12) between them, - a system (38) for illuminating the strand (12) in the illumination cavity (34). The kit (10) comprises a device (18) for controlling the illumination received by a treated area (19), comprising a measuring device (60) configured to measure the total light energy received by the treated area (19) and a safety device (62) configured to emit a warning signal and/or stop the illumination of the treated area (19) when the light energy measured exceeds a threshold value.

Description

TITLE: Kit for keratinic fibers strand and related treatment process

The present invention relates to a kit for strand of keratin fibers comprising at least one device for illuminating at least one strand of keratin fibers, the illumination device comprising:

- a first arm and a second arm that are movable in relation to each other between an open position for insertion of the strand and a closed position for containment of the strand wherein the arms define between them a cavity for illuminating the strand,

- a system for illuminating the strand in the illumination cavity, capable of illuminating the strand.

The kit is in particular intended to be used for hair treatment. The aim of the treatment is in particular that of producing under illumination a decolorizing of the hair, or of fixing a wash-resistant coating on the hair in order to give the hair a volume effect.

WO 2017/108767, WO 2004/054527 and WO 2007/048472 describe the cosmetic coating compositions that can be applied on hair, which include photocrosslinkable compounds. The document WO 2007/048472 describes for its part cosmetic compositions for treating hair comprising photopolymerizable compounds

After application of a cosmetic composition on the hair, a illumination device which may consist in the first and last document of light-emitting diodes (referred to using the acronym "LED"), is passed over the strands of hair to crosslink or polymerize the photosensitive compounds and thus obtain the sought effect.

As a general rule, the light emitted is in the UV-visible range, at energy doses of the order of one Joule/cm².

In other cases, when a photo-oxidation must be performed to decolorize the hair, as in WO 2015/165949, hair treated with a composition comprising a chemical oxidant undergoes a light application with a device which may consist of light-emitting diodes. The illumination device is generally used at higher powers, of the order for example of around one hundred Joules/cm².

Prior to the illumination step, the hair strands on which the cosmetic composition has been applied are generally separated from the rest of the hair and enclosed inside a foil. The foil holds the coating or decolorizing composition on the hair strands and also prevents direct contact between the hair and the illumination device.

The illumination devices cited above are very effective for providing effective irradiation of the hair strand. However, their use is complex and generally requires the presence of a professional trained in handling such devices. Poor handling is liable to cause light scattering outside the desired treatment area which results in a degraded treatment, and/or in an alteration of the untreated hair and in a risk for the user. There may also be a risk of overexposure of the hair causing an alteration of its integrity.

WO2020/23431 1 describes an illumination device comprising an optical system capable of measuring the movement speed of the device with respect to a foil having an optical scale. The illumination power is then modified to maintain a regular illumination level while the illumination device passes over the foil, preventing overexposure of the strand disposed in the foil.

The illumination device cited above is effective for providing regular irradiation of the hair strand.

However, there is still a need for improvement, in particular in respect of user protection against light, to limit or even prevent overexposure risks and to enhance the reproducibility of the illumination conditions from one treated area to another.

One aim of the invention is therefore that of providing a kit for keratin fiber strands which makes it possible to carry out treatments requiring an illumination of the strand, by substantially limiting, or preventing risks of exposure to light, and by enhancing the reproducibility of the treatment carried out.

To this end, the invention relates to a kit of the type cited above, characterized in that the kit further comprises a device for controlling the illumination received by a treated area, the treated area being a strand or a portion of strand, the control device comprising a measuring device configured to measure the total light energy associated with the radiation from the illumination system received by the treated area and a safety device configured to emit a warning signal and/or stop the illumination of the treated area when the light energy measured exceeds a threshold value.

The illumination control device makes it possible to control the total light energy received by a treated area and, by warning the user and/or switching off the illumination, prevent overexposure of the keratin fibers.

When the total light energy measured reaches the threshold value, the user is thus informed, for example via a luminous or audible signal, and/or the illumination is stopped.

For example, the threshold value is integrated beforehand at the illumination device. Advantageously, the threshold value is entered beforehand by the user, for example according to the hair type.

The reproducibility of the illumination conditions from one treated area to another is also enhanced, by making it possible to control the light energy received by each area. The kit according to the invention can comprise one or more of the following features, taken alone or in any technically possible combination.

According to a variant, the measuring device comprises a sensor capable of quantifying the energy received associated with the radiation from the illumination system, the sensor being preferably an energy integrating photometer.

The sensor makes it possible to accurately measure the total light energy received by the treated area, and thus prevent the light energy measured from exceeding a threshold value.

According to a variant, the kit further comprises a foil for strand of keratin fibers including a first sheet and a second sheet movable in relation to the first sheet between a closed configuration for illumination of the strand and an open configuration, at least the first sheet being substantially transparent at least partially to UV-visible light, the measuring device being preferably integrated in the foil.

The keratin fiber strands are thus held between the sheets of the foil during the strand illumination treatment.

The keratin fibers disposed between the first and the second sheets of the foil thus receive a maximum illumination, with a reduced light loss. The body surfaces disposed near the foil are furthermore protected.

According to a variant of the invention, the measuring device is integrated in the foil.

The light energy received is then measured at the foil. Said energy is returned to the safety device either continuously after each pass of the measuring device under the illumination device, or after a predefined number of passes, or when the total light energy measured exceeds the threshold value.

According to a further variant of the invention, the measuring device is integrated in the illumination device.

The light energy received is then measured at the illumination device.

In an embodiment, the control device further comprises an area changing device configured to send a reset instruction to the measuring device when moving from one treated area to the next.

When moving from one treated area to another, for example from one strand to another, the measuring device is thus reset and the measured light energy is reset to zero.

Preferably, the area changing device comprises at least one of the following elements selected from:

- a manual activator, preferably a button, capable of being activated by a user when moving from one treated area to the next; - an optical system capable of measuring a movement of the illumination device in relation to the strand;

- a sensor of the opening of the illumination device configured to determine the switch of the illumination device from the closed position to the open position.

According to a variant of the invention, the kit further comprises at least one cosmetic composition for keratin fibers suitable for being applied on the strand of keratinic fibers.

The invention also relates to a method for treating at least one strand of keratinic fibers including the following steps:

- providing a kit of the type cited above, the illumination device being in the open position;

- inserting a strand into the illumination cavity of the illumination device, said cavity defining the treated area;

- closing the illumination device;

- activating the illumination system; and

- measuring the total light energy associated with the radiation from the illumination system received by the treated area.

According to a variant, the method comprises an emission step wherein the safety device emits a warning signal when the light energy measured during the measuring step exceeds the threshold value.

The user is thus warned that the light energy measured exceeds a threshold value and can either change treated area, or switch off the illumination, in order to prevent overexposure of the treated area.

According to a variant, the process comprises a step of shutting down the illumination system when the light energy measured during the measuring step exceeds the threshold value.

The automatic switching off of the illumination reduces or even prevents the risks of overexposure of the treated area.

According to a variant, wherein the kit comprises a foil of the type cited above, the step of inserting the strand into the illumination cavity comprising the following sub-steps:

- inserting the strand between the first sheet and the second sheet of the foil, the foil being in the open configuration;

- closing the foil, the strand being between the first and the second sheets;

- disposing the foil in the closed configuration in such a way that the first sheet is located facing the illumination system of the illumination device. According to a variant, the method further comprises a step of relative movement of the illumination device in relation to the strand when the strand is inserted into the illumination cavity.

The total treated area after the or any step(s) of relative movement of the illumination device in relation to the strand then corresponds advantageously to at least 30% of the length of the strand, preferably at least 50% of the length of the strand, even more preferably at least 70% of the length of the strand.

According to a variant, the method further comprises a step of changing treated area, carried out either by activation by a user of a manual activator, preferably a button, or automatically after a pre-defined number of passes over a strand, or by inserting a new strand into the illumination cavity, or by relative movement of the illumination device in relation to the strand.

The change of treated area may thus be carried out manually by the user, or automatically.

According to a variant, the method comprises prior to the insertion of the strand into the illumination cavity a step of applying at least one cosmetic composition on the strand.

In a variant of this process, the strand is pre-treated with at least one cosmetic composition.

According to a variant, the cosmetic composition comprises at least one chemical oxidizing agent.

Preferably, the chemical oxidizing agent is hydrogen peroxide alone or in combination with at least one persalt and in particular at least one persulfate.

Preferably, the composition comprises at least one chemical oxidizing agent comprises at least one alkaline agent. The alkaline agent(s) may be mineral or organic.

According to a further variant, the cosmetic composition comprises at least one photocrosslinkable compound, even more preferably a photodimerizable compound.

Preferably, the photocrosslinkable compound is a polymer. Even more preferably, the photocrosslinkable polymer is an optionally hydrophobized PVASBQ.

The cosmetic composition comprising the chemical oxidant(s) and/or the photocrosslinkable compound(s) may also comprise at least one compound selected from solvents, optionally silicone fats, optionally silicone anionic, cationic, non-ionic or amphoteric surfactants, non-photocrosslinkable polymers and in particular anionic, cationic, non-ionic or amphoteric treating, styling or thickening polymers, synthetic or natural soluble coloring agents, pigments, disulfide bond-breaking agents, oxidizing agents, anti-dandruff agents and anti-hair loss agents. The composition applied on the hair in the processes of the invention may result from mixing at least two compositions at the time of use. This is in particular the case for decolorizing where the cosmetic composition applied on the hair results preferably from mixing at the time of use two compositions, of which one contains hydrogen peroxide or a hydrogen peroxide precursor, the second composition containing at least one alkaline agent. Even more preferably, the first composition is aqueous and contains hydrogen peroxide and the second composition is anhydrous.

The keratin fibers are preferably human hair or extensions.

The invention will be easier to understand after reading the following description, provided solely as an example, and with reference to the appended drawings, wherein:

[Fig 1 ] Figure 1 is a schematic three-quarter front perspective view of a kit according to a first embodiment of the invention during the illumination of a keratin fiber strand, the kit comprising an illumination device and a foil into which the strand is inserted, and

[Fig 2] Figure 2 is a schematic view of a foil according to a second embodiment of the invention.

A kit 10 for keratin fiber strands according to the invention is represented in Figure 1.

The kit 10 is intended to illuminate at least one keratin fiber strand 12, for example pre-treated with a cosmetic composition. Preferably, the keratin fibers are hair.

In a variant, the cosmetic composition contains at least one photocrosslinkable polymer which crosslinks during the illumination treatment of the strand 12 by the kit 10.

In a further variant, the kit 10 is intended to illuminate the keratin fiber strand 12 to decolorize the strand 12 which may be pre-treated with a composition containing at least one oxidizing agent.

With reference to Figure 1 , the kit 10 includes a device 14 for illuminating at least one keratin fiber strand 12. According to a preferential embodiment, represented in Figure 1 , the kit 10 also includes a foil 16 for a keratin fiber strand 12.

The kit 10 also includes a device 18 for controlling the illumination received by a treated area 19, the treated area 19 being a strand 12 or a strand portion 12.

Advantageously, the kit 10 also includes a cosmetic product for keratin fibers capable of being applied on the keratin fiber strand 12.

The illumination device 14 according to the invention is illustrated in Figure 1. The illumination device 14 is here a grip and is intended to illuminate the strand 12 of hair to perform for example the illumination of a strand 12 optionally pre-treated with a cosmetic composition, for example to decolorize it. With reference to Figure 1 , the illumination device 14 includes a first arm 30 and a second arm 32, the arms 30, 32 being mounted movable in relation to each other between an open position for inserting the strand 12, optionally covered with the foil 16, into the illumination device 14 and a closed position for containing the strand 12 in an illumination cavity 34 between the first arm 30 and the second arm 32, see in Figure 1 . Advantageously, the illumination device 14 comprises an opening sensor (not shown) configured to determine the switch of the illumination device 14 from the closed position to the open position.

The device 14 further includes a joint assembly 36 of the first arm 30 with the second arm 32 and a system 38 for illuminating the strand 12 in the illumination cavity 34.

According to a particular embodiment, the illumination device 14 further includes an optical system 39 capable of measuring a movement of the illumination device 14 in relation to the strand 12 and/or the foil 16.

The first arm 30 extends along a longitudinal axis X-X’ and has a first inner surface delimiting a first side the illumination cavity 34. The second arm 32 extends along a longitudinal axis Y-Y’ and has a second inner surface delimiting a second side the illumination cavity 34.

In this example, the first arm 30 and the second arm 32 are mounted movable in relation to each other in rotation, via the joint assembly 36 between the open position and the closed position. The rotation is performed about an axis Z-Z’ perpendicular to the longitudinal axis X-X’, Y-Y’ of each arm 30, 32.

In the open position of the illumination device 14, the first arm 30 is moved partially away from the second arm 32. The volume of the intermediate space between the arms 30, 32, taken between the first inner surface and the second inner surface, is maximal to allow easy insertion of the strand 12, optionally covered with the foil 16, between the arms 30, 32.

In the closed position of the illumination device 14, seen in Figure 1 , the first arm 30 and the second arm 32 are moved closer together to place their longitudinal axes X-X’ and Y-Y’ substantially parallel with each other.

The first inner surface and the second inner surface are then located facing each other. The volume of the intermediate space between the arms 30, 32, taken between the first inner surface and the second inner surface, is then minimal.

The illumination system 38 includes at least one light source 40 and preferably at least one operation controller 42 of the or each light source 40. The light source 40 is mounted on at least one of the first and the second arm 30, 32, preferably on only one of the two arms 30, 32, on the inner surface. In Figure 1 , the light source 40 is mounted on the first arm 30.

The light source 40 is for example formed by at least one light-emitting diode, preferably by a group of light-emitting diodes emitting in the UV-Visible range.

The illumination produced by the light source 40 is preferably produced in the range of wavelengths ranging from 280 nanometers to 700 nanometers (nm) and preferably from 350 to 500 nm.

Advantageously, the light source 40 is capable of developing an irradiance greater than 0.3 W/cm², preferably between 0.5 W/cm² and 50 W/cm².

The light source 40 is powered by a power supply device (not shown). Said power supply device is for example integrated in the illumination device 14 or located nearby, in particular in the arm carrying this illumination device 14. Alternatively, the power supply device is offset onto an external device, the power supply of the light source 40 being for example carried out by connecting the illumination device 14 to said power supply device by wired means.

Preferably, the activation of the illumination system 38, and more specifically of the light source 40, is controlled on the closure of the illumination device 14. In other words, when the illumination device is in the open position, the illumination power developed by the light source 40 is zero.

The optional optical system 39 is capable of measuring the movement of the illumination device 14 in relation to the strand 12 and/or the foil 16.

Preferably, the optical system 39 includes an optical sensor (not shown) arranged on one of the first and the second arm 30, 32. The optical sensor is for example a CCD (charge-coupled device) sensor or CMOS (complementary metal-oxide-semiconductor) sensor type sensor.

With reference to Figure 1 , the foil 16 includes a first sheet 50 and a second sheet 52. Preferably, the first sheet 50 is connected to the second sheet 52 via an articulation 54, or assembly means 54.

The articulation 54 is for example a bond or a weld or an adhesive or a tacking or a Velcro device or a seam. The articulation 54 is performed along an assembly line. For example, the articulation is a hinge.

Advantageously, the foil 16 also comprises a sealing means 58 capable of sealing the foil 16 in the closed configuration. The first and second sheets 50, 52 are capable of having any shape and any dimensions suitable for the application of a cosmetic product on a strand of hair. In the example illustrated in Figure 1 , the first and second sheets 50, 52 are of rectangular shape.

The first sheet 50 is at least partially, preferably totally, substantially transparent to UV-visible light. "Substantially transparent to light" means that the first sheet 50 has a transmittance greater than 75% in the wavelength region ranging from 350 nm to 500 nm, preferably from 280 nm to 700 nm, the transmittance being measured via a polychromatic light source and a spectrometer, or via a monochromatic source and a photon counter. This transmittance value is determined at ambient temperature (23°C+/- 5°C) and at atmospheric pressure (approximately 1013 hPa).

The first sheet 50 is made of a plastic material. This plastic material is preferably heat-resistant and has a satisfactory resistance up to at least 150°C. This means that the mechanical and optical properties of the material are not degraded at temperatures of up to at least 150°C. Even more preferably, this material is a polyethylene terephthalate (referred to as PET).

Preferably, the second sheet 52 is at least partially, preferably totally, substantially opaque to UV-visible light. The second sheet 52 preferably has a transmittance less than 5% in the wavelength region ranging from 350 nm to 500 nm, preferably from 280 nm to 700 nm, the transmittance being measured via a polychromatic light source and a spectrometer, or via a monochromatic source and a photon counter. This transmittance value is determined at ambient temperature (23°C+/- 5°C) and at atmospheric pressure (approximately 1013 hPa).

The second sheet 52 is preferably made of a material selected in the group consisting of opaque plastics (opaque polycarbonates, opaque polyethylenes, opaque polypropylenes, etc.), metals such as aluminum, and paper. According to a specific embodiment, the second sheet 52 is a sheet of aluminum or paper covered with a plastic coating which ensures superior rigidity while maintaining flexibility.

Preferably, at least one, advantageously each, of the first sheet 50 and the second sheet 52 includes at least one liquid-tight layer and capable of retaining a cosmetic product applied on the sheet 50, 52 without the product impregnating or passing through the sheet 50, 52

It is hence possible to apply a product on a strand 12 placed on the exposed surface of the sheet 50, 52, without the product passing through the sheet 50, 52.

Preferably, each of the first sheet 50 and the second sheet 52 is capable of resisting high temperatures, typically greater than 150°C. "Capable of resisting" means that the mechanical and optical properties of the sheet 50, 52 are not degraded. Preferably, when the first 50 and/or the second sheet 52 is made of a plastic material, said first and/or second sheet 50, 52 has a vitreous transition temperature greater than 80°C.

Each of the first sheet 50 and the second sheet 52 is preferably capable of resisting the cosmetic products susceptible to be applied on the strand 12. For example, each of the first sheet 50 and the second sheet 52 is capable of resisting products comprising a decolorizing product, for example an oxidizing product such as hydrogen peroxide.

In Figures 1 and 2, the articulation 54 is rectilinear and extends along a longitudinal axis between the first sheet 50 and the second sheet 52, preferably along the entire length of the sheets 50, 52.

The first sheet 50 is movable in relation to the second sheet 52 about the articulation 54 between a closed configuration for illumination of the strand 12 and an open configuration.

In the open configuration, the sheets 50, 52 are only in contact with each other at the articulation 54. The sheets 50, 52 define between them a reception space intended to receive at least one keratin fiber strand 12. In the open configuration, the volume of the reception space is large enough to allow an easy insertion of the strand 12 between the sheets 50, 52.

In the closed configuration for illumination of the strand 12, the sheets 50, 52 surrounding the strand 12 find themselves in contact with each other and the volume of the reception space is minimal.

As indicated in Figure 2, optionally, the foil 16 comprises a sealing means 58 disposed along a free edge of the first and/or the second sheet 50, 52. For example, the sealing means 58 is an adhesive or a Velcro system disposed along said free edge.

The sealing means 58 prevents the keratin fibers of the strand 12 from coming out of the side of the foil 16 when the foil 16 is in the closed illumination configuration.

Advantageously, the sealing means 58 is not permanent and the foil 16 is capable of switching from the closed configuration to the open configuration by detaching the first sheet 50 and the second sheet 52.

The illumination control device 18 comprises a measuring device 60 configured to measure the total light energy received by the treated area 19 and a safety device 62 intended to prevent overexposure of the first treated area 19.

The total light energy measured corresponds to the received light power multiplied by the illumination time.

Preferably, the measuring device 60 comprises a sensor 64 capable of quantifying the energy received by the treated area associated with the radiation from the illumination system 38. The sensor 64 is preferably an energy integrating photometer.

According to a first embodiment shown in Figure 1 , the measuring device 60 is integrated in the illumination device 14, in particular at the first or second arm 30, 32.

In the example of Figure 1 , the sensor 64 is integrated in the second arm 32 and is configured to receive the radiation from the illumination system 38 directly.

Preferably, the measuring device 60 further comprises a microcontroller 66 configured to transmit an overshoot signal to the safety device 62 when the total light energy measured by the sensor 64 reaches and/or exceeds a threshold value.

The threshold value corresponds to the maximum authorized light energy for a treated area.

Advantageously, the threshold value is adjustable by the user, for example via a setting device (not shown) disposed on one of the arms 30, 32 of the illumination device 14. The threshold value is for example adjustable according to the hair type or treatment selected (sheathing or decolorizing).

Typically, the threshold value is less than 120 J/cm².

The safety device 62 is preferably integrated in the illumination device 14. The safety device 62 is configured to emit a safety instruction when the light energy measured exceeds a threshold value, in particular when it receives an overshoot signal transmitted by the measuring device 60.

For example, the safety instruction comprises emitting a warning signal. The safety device 62 is configured to emit a warning signal when the total light energy measured exceeds the threshold value. The warning signal comprises for example an audible signal and/or a luminous signal.

Alternatively or additionally, the safety instruction comprises automatic switching off the illumination of the treated area 19. The safety device 62 is configured to transmit an illumination switching off instruction to the illumination system 38, in particular to the operating controller 42 of the or each light source 40.

In the example of Figure 1 , the safety device includes a memory 70 and a processor 72 associated with said memory 70.

The control device 18 can implement a software program, or a software component, executable by the processor 72. The memory 70 of the control device 18 is then capable of storing a software program for establishing a safety instruction and a software program for transmitting at least one safety instruction, in particular an illumination interruption instruction to the illumination system 38, in particular to the controller 42. The processor 72 is then capable of executing each of the establishing and transmission software programs. Advantageously, the control device 18 further comprises an area changing device 76 configured to send a reset instruction, also referred to as reset to zero instruction, to the measuring device 60.

The measuring device 60 is configured to receive said reset instruction and, following the receipt of said instruction, reset the light energy measured to zero.

The area changing device 76 thus makes it possible to reset the measuring device 60 when moving from one treated area 19 to the next.

Said move may correspond for example to a change of strands.

Alternatively, when the treated area corresponds to a portion of a strand 12, said move corresponds to moving the illumination device 14 along said strand 12 so as to illuminate an area which was not previously illuminated by the illumination device 14.

For example, as shown in Figure 1 , the area changing device 76 comprises a manual activator 78, preferably a button, for example disposed on one of the arms 30, 32 of the illumination device 14.

The manual activator 78 is configured to be activated by a user when moving from one treated area 19 to the next, for example when changing strands.

In a variant not shown, the area changing device 76 is configured to send a reset instruction automatically to the measuring device 60.

For example, when the illumination device 14 comprises an opening sensor (not shown) configured to determine the illumination device 14 moving from the closed position to the open position, said opening sensor is advantageously configured to transmit a signal to the area changing device 76 during the opening of the illumination device 14, the area changing device 76 then being configured to transmit the reset instruction to the measuring device 60.

According to a further example, the area changing device 76 is configured to transmit the reset instruction to the measuring device 60 after a predetermined number of passes over a strand 12.

According to a further example, the area changing device 76 is configured to transmit the reset instruction to the measuring device 60 after a movement of the illumination device 14 along the strand 12 by a predetermined distance, said distance corresponding typically to the length of the treated area 19 when the latter corresponds to a portion of the strand 12. Said movement is preferably measured by the optical system 39.

The operation of the kit 10 for a keratin fiber strand 12 according to the first embodiment will now be described.

According to an optional step, the user initially places the foil 16 in the open position and inserts the strand 12 intended to undergo an illumination between the first sheet 50 and the second sheet 52 of the foil 16. Then, the user moves the foil 16 to its closed illumination position by moving the first sheet 50 and the second sheet 52 closer together.

When the foil 16 includes a sealing means 58, the latter is implemented in order to prevent keratin fibers of the strand 12 from coming out of the foil 16 during the passage of the illumination device 14.

In the case of a photocrosslinking treatment, the strand 12 has been prior to illumination been coated with a cosmetic composition containing at least one photocrosslinkable compound.

In the case of a decolorizing treatment, the strand 12 is for example prior to illumination coated with a cosmetic composition containing at least one oxidizing compound.

Then, the user places the illumination device 14 in the open position and inserts the strand 12, optionally inserted into the foil 16, between the first arm 30 and the second arm 32 into the illumination cavity 34.

When the strand 12 is inserted into a foil 16, the strand 12 is disposed in the illumination cavity 34 in such a way that the first sheet 50 is located facing the illumination system 38, in particular the light source(s) 40.

Then, the user moves the illumination device 14 to its closed position by moving the first arm 30 and the second arm 32 closer together. During this approach, the inner surface of the first arm 30 is placed facing the inner surface of the second arm 32 to close the illumination cavity 34.

The user activates the illumination system 38. The controller 42 controls the light source 40 to apply the desired illumination on a treated area 19.

The control device 18 controls the light energy received by said treated area 19.

The measuring device 60 measures the total light energy received by the treated area 19, preferably by means of the sensor 64.

When the measured total light energy reaches and/or exceeds the threshold value, the measuring device 60 sends, preferably via its microcontroller 66, an overshoot signal to the safety device 62.

Advantageously, said threshold value has been previously entered by the user by means of a setting device.

The safety device 62 then emits a safety instruction intended to prevent overexposure of the treated area 19.

For example, the safety device 62 emits an audible and/or visual warning signal. The user is thus informed that the total light energy received by the treated area 19 has reached and/or exceeded the threshold value. Alternatively or additionally, the safety device 62 transmits an illumination switching off instruction to the illumination system 38, in particular to the operating controller 42 of the or each light source 40. The illumination of the treated area 19 is then switched off.

According to a specific embodiment, the user then moves the illumination device 14 along the strand 12 during the illumination of a new area thereof.

The optical system 39, when it is present, measures via the optical sensor the movement of the illumination device 14 in relation to the strand 12.

Alternatively, the illumination device 14 is kept stationary in relation to the strand 12 during the illumination thereof.

Preferably, during the treatment of one or more strands 12, several treated areas are illuminated successively and the treatment process then comprises a step of changing treated area.

For example, the user indicates the move from one treated area to another, for example following the movement of the illumination device 14 or a change of strands 12, by activating the manual activator 78, in particular by pressing a button.

Alternatively, the area changing device 76 automatically sends the reset instruction to the measuring device 60, following one of the actions selected from opening the illumination device 14, a predetermined number of passes over a strand 12 and moving the illumination device 14 by a predetermined distance along the strand 12.

After moving from one treated area 19 to another, the area changing device 76 sends a reset instruction to the measuring device 60 which restarts from zero to quantify the light energy measured.

Then, the user opens the illumination device 14 again to extract the strand 12. Optionally, the user places another strand 12 between the arms 30, 32.

The kit 10 according to the invention is thus easy to use.

Even in the case of incorrect use, for example when the illumination device 14 is passed along the strand 12 too slowly, the illumination level viewed by the strand 12 is kept at a level below a threshold value, ensuring an optimal treatment of the keratin fibers and limiting the risks of overexposure.

The kit 10 and the treatment process according to the invention thus make it possible to obtain enhanced and safer illumination conditions, by controlling the light energy received by the keratin fibers.

The risks of degradation of the keratin fibers due to overexposure, as well as the risks of a degraded treatment, are reduced.

Furthermore, the control of the light energy received by the strand is more effective, making it possible to obtain reproducible results from one treated area to another. In a variant, the first sheet 50 and the second sheet 52 are separated and the foil 16 is devoid of an articulation 54.

According to a variant, the foil 16 consists of a single sheet, the articulation 54 corresponding to a folding line of said sheet. According to a variant, the foil 16 is made entirely of transparent or translucent plastic material, in particular of polypropylene.

According to a second embodiment represented in part in Figure 2, the measuring device 60 of the control device 18 is integrated in the foil 16.

For example, the measuring device 60 comprises a sensor 80 disposed on one of the sheets 50, 52 of the foil 16 so as to receive the radiation directly from the illumination system 38. Advantageously, the sensor 80 is capable of transmitting an overshoot signal to the safety device 62 when the total light energy measured by the sensor 80 reaches and/or exceeds the threshold value.

A person skilled in the art will understand that the invention is not limited to the embodiments described, or to the specific examples from the description, the embodiments and the variants mentioned above being capable of being combined together to generate novel embodiments of the invention.

Claims

1. Kit (10) for a strand (12) of keratin fibers comprising at least one device (14) for illuminating at least one strand (12) of keratin fibers, the illumination device (14) comprising:

- a first arm (30) and a second arm (32) that are movable in relation to each other between an open position for insertion of the strand (12) and a closed position for containment of the strand (12), wherein the arms (30, 32) define between them a cavity (34) for illumination of the strand (12),

- a system (38) for illuminating the strand (12) in the illumination cavity (34), capable of illuminating the strand (12), characterized in that the kit (10) further comprises a device (18) for controlling the illumination received by a treated area (19), the treated area (19) being a strand (12) or a portion of strand (12), the control device (18) comprising a measuring device (60) configured to measure the total light energy associated with the radiation from the illumination system (38) received by the treated area (19) and a safety device (62) configured to emit a warning signal and/or stop the illumination of the treated area (19) when the measured light energy exceeds a threshold value.

2. Kit (10) according to the preceding claim, wherein the measuring device (60) comprises a sensor (64; 80) capable of quantifying the energy received associated with the radiation from the illumination system (38), the sensor (64) being preferably an energy integrating photometer.

3. Kit (10) according to any of claims 1 or 2, further comprising a foil (16) for strand (12) of keratin fibers including a first sheet (50) and a second sheet (52) movable in relation to the first sheet (50) between a closed configuration for illumination of the strand (12) and an open configuration, at least the first sheet (50) being substantially transparent at least partially to UV-visible light, the measuring device (60) being preferably integrated in the foil(16).

4. Kit (10) according to any of claims 1 to 3, wherein the measuring device (60) is integrated in the illumination device (14).

5. Kit (10) according to any of the preceding claims, wherein the control device (18) further comprises an area changing device (76) configured to send a reset instruction to the measuring device (60) when moving from one treated area (19) to the next.

6. Kit (10) according to the preceding claim, wherein the area changing device (76) comprises at least one of the following elements selected from: a manual activator (78), preferably a button, capable of being activated by a user when moving from one treated area (19) to the next; an optical system (39) capable of measuring a movement of the illumination device (14) in relation to the strand (12); a sensor of the opening of the illumination device (14) configured to determine the switch of the illumination device (14) from the closed position to the open position.

7. Kit (10) according to any of the preceding claims, further comprising at least one cosmetic composition for keratin fibers suitable for being applied on the strand (12) of keratin fibers.

8. Method for treating at least one strand (12) of keratin fibers including the following steps:

- providing a kit (10) according to any of the preceding claims, the illumination device (14) being in the open configuration;

- inserting a strand (12) into the illumination cavity (34) of the illumination device (14), said cavity defining the treated area (19);

- closing the illumination device (14);

- activating the illumination system (38); and

- measuring the total light energy associated with the radiation from the illumination system (38) received by the treated area (19).

9. Method according to the preceding claim, comprising an emission step wherein the safety device (62) emits a warning signal when the light energy measured during the measuring step exceeds the threshold value.

10. Method according to any one of claims 8 or 9, comprising a step of shutting down the illumination system (38) when the light energy measured during the measuring step exceeds the threshold value.

11 . Method according to any one of claims 8 to 10, wherein the kit (10) comprises a foil (16) according to claim 3, the step of inserting the strand (12) into the illumination cavity (34) comprising the following sub-steps: - inserting the strand (12) between the first sheet (50) and the second sheet (52) of the foil (16), the foil (16) being in the open configuration;

- closing the foil (16), the strand (12) being between the first and the second sheets (50, 52);

- disposing the foil (16) in the closed configuration in such a way that the first sheet (50) is located facing the illumination system (38) of the illumination device (14).

12. Method according to any of claims 8 to 11 , further comprising a step of relative movement of the illumination device (14) in relation to the strand (12) when the strand (12) is inserted into the illumination cavity (34).

13. Method according to any one of claims 8 to 12, further comprising a step of changing treated area (19), carried out either by activation by a user of a manual activator (78), preferably a button, or automatically after a pre-defined number of passes over a strand (12), or by inserting a new strand (12) into the illumination cavity (34), or by relative movement of the illumination device (14) in relation to the strand (12).

14. Method according to any one of claims 8 to 13, comprising, prior to the insertion of the strand (12) into the illumination cavity (34), a step of applying at least one cosmetic composition on the strand (12).